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Sample records for abscess gas formation

  1. Abscess

    MedlinePlus

    ... liver abscess Anorectal abscess Bartholin abscess Brain abscess Epidural abscess Peritonsillar abscess Pyogenic liver abscess Skin abscess Spinal ... Anorectal abscess Bartholin cyst or abscess Brain abscess Epidural abscess Peritonsillar abscess Pyogenic liver abscess Skin abscess Spinal ...

  2. Hepatic mucormycosis with abscess formation.

    PubMed

    Su, Henry; Thompson, George R; Cohen, Stuart H

    2012-06-01

    We describe a case of hepatic mucormycosis with abscess, an uncommon presentation of mucormycetes infection. Our patient was initially treated with transcutaneous pigtail catheter placement, liposomal amphotericin B, and micafungin without improvement. The patient subsequently improved after hepatic segmentectomy and hemidiaphragm resection. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Serratia marcescens spinal epidural abscess formation following acupuncture.

    PubMed

    Yang, Chih-Wei; Hsu, Shun-Neng; Liu, Jhih-Syuan; Hueng, Dueng-Yuan

    2014-01-01

    The formation of spinal epidural abscess following acupuncture is very rare. We herein report the case of a 54-year-old woman who presented with progressive low back pain and fever with a root sign. She underwent surgical decompression, with an immediate improvement of the low back pain. A culture of the epidural abscess grew Serratia marcescens. One year postoperatively, magnetic resonance imaging revealed the almost complete eradication of the abscess. This case is the first case of Serratia marcescens-associated spinal epidural abscess formation secondary to acupuncture. The characteristics of spinal epidural abscess that develop after acupuncture and how to prevent such complications are also discussed.

  4. Abscess

    MedlinePlus

    An abscess is a pocket of pus. You can get an abscess almost anywhere in your body. When an area ... parasites and swallowed objects can all lead to abscesses. Skin abscesses are easy to detect. They are ...

  5. Abscess

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Abscess KidsHealth > For Teens > Abscess A A A What's ... and suddenly it's Pus City. What Is an Abscess? An abscess is an area of infected tissue ...

  6. Rapidly Progressive Gas-containing Lumbar Spinal Epidural Abscess

    PubMed Central

    Bang, Jin Hyuk

    2015-01-01

    Gas-containing (emphysematous) infections of the abdomen, pelvis, and extremities are well-known disease entities, which can potentially be life-threatening. They require aggressive medical and often surgical treatment. In the neurosurgical field, some cases of gas-containing brain abscess and subdural empyema have been reported. Sometimes they progress rapidly and even can cause fatal outcome. However, gas-containing spinal epidural abscess has been rarely reported and clinical course is unknown. We report on a case of rapidly progressive gas-containing lumbar spinal epidural abscess due to Enterococcus faecalis in a 72-year-old male patient with diabetes mellitus. PMID:26512268

  7. Rapidly Progressive Gas-containing Lumbar Spinal Epidural Abscess.

    PubMed

    Bang, Jin Hyuk; Cho, Keun-Tae

    2015-09-01

    Gas-containing (emphysematous) infections of the abdomen, pelvis, and extremities are well-known disease entities, which can potentially be life-threatening. They require aggressive medical and often surgical treatment. In the neurosurgical field, some cases of gas-containing brain abscess and subdural empyema have been reported. Sometimes they progress rapidly and even can cause fatal outcome. However, gas-containing spinal epidural abscess has been rarely reported and clinical course is unknown. We report on a case of rapidly progressive gas-containing lumbar spinal epidural abscess due to Enterococcus faecalis in a 72-year-old male patient with diabetes mellitus.

  8. Gas-containing brain abscess: etiology, clinical characteristics, and outcome.

    PubMed

    Su, Tsung-Ming; Lan, Chu-Mei; Lee, Tsung-Han; Hsu, Shih-Wei

    2014-12-01

    Gas-containing brain abscess remains a life-threatening disease that requires immediate diagnostic and therapeutic intervention. The aim of this study is to report on a series of gas-containing brain abscess and discuss its pathological mechanism and therapeutic consideration. This study included 11 patients with gas-containing brain abscess at Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan during a 27-year period. The predisposing factors to infection included hematogenous spread in five patients, contiguous infection in one patient, and abnormal fistulous communication due to head injury in four patients. In one patient, the predisposing factor might be contiguous infection from frontal sinusitis or abnormal fistulous communication due to previous sinus surgery. Klebsiella pneumoniae was the most common causative pathogen that was isolated from the gas-containing abscess not related to skull base defect. Among these 11 patients, six underwent excision and five accepted aspiration for the surgical treatment of abscess. In the five patients who underwent aspiration, two required repeated craniotomy to excise the recurrent abscess and repair the abnormal fistulous communication through the skull base. When encountered with a gas-containing abscess in patients with an impaired host defense mechanism, K. pneumoniae infection should be suspected, and further attention should be paid to discovering if other metastatic septic abscesses exist. For patients with a history of basilar skull fracture or surgery involving the skull base, craniotomy is indicated to excise the abscess and repair the potential fistulous communication through the cranium. Aspiration may be a reasonable alternative to treat deep-seated lesions, lesions in an eloquent area, patients with severe concomitant medical disease, or patients without a history of basilar skull fracture or surgery involving the skull base. Prompt diagnosis, appropriate antibiotic use, and meticulous surgical

  9. Liver Abscess Formation Following Transarterial Chemoembolization

    PubMed Central

    Lv, Wei-Fu; Lu, Dong; He, Yu-Sheng; Xiao, Jing-Kun; Zhou, Chun-Ze; Cheng, De-Lei

    2016-01-01

    Abstract To investigate the clinical features, risk factors, and bacterial spectrum of liver abscess following transarterial chemoembolization (TACE) and evaluate the therapeutic effect of percutaneous catheter drainage (PCD) on the abscesses. A retrospective review of patient charts was performed in 3613 patients who suffered from liver malignancies (2832 patients with hepatocellular carcinoma and 781 with metastatic hepatic tumor) and had undergone 11,054 TACE procedures from January 2005 to October 2013. Liver abscesses were found in 21 patients. PCD was performed in all abscess patients. The clinical features, risk factors, and bacterial spectrum of liver abscess following TACE were investigated and the therapeutic effect of PCD was evaluated. The incidence of liver abscess was 0.58% per patient and 0.19% per procedure. Approximately 57.1% of the patients had a medical history of bilioenteric anastomosis or biliary stent implantation. On computed tomography scans, the abscesses appeared as low-attenuation lesions and high-density iodinate oil scattered in the abscesses. The ultrasound showed the well defined, heterogeneously hypoechoic lesions. Positive microbiological isolates were obtained in all pus cultures and in 47.6% of blood cultures. The most common bacterium was Escherichia coli (52.4%). Twenty patients (95.2%) were cured from abscesses by using PCD, and 1 died of sepsis. Patients with predisposing factors are prone to an increased risk of liver abscess following TACE. Bacterial culture and antibiotic sensitivity tests on pus and blood help on the antibiotics selection. PCD combined with aggressive antibiotics can be recommended as the first-line therapeutic regimen. PMID:27124055

  10. Hepatic metastasis complicated by abscess formation.

    PubMed

    Yi, Liao; Lihua, Qiu; Xianming, Diao; Qiyong, Gong

    2015-01-01

    Hepatic abscesses and hepatic metastasis are common diseases. However, hepatic abscesses seldom occur in patients with hepatic metastases. We describe a case of a 67-year-old female patient with abdominal pain in the right upper quadrant. Magnetic resonance imaging revealed several lesions, with the largest lesion displaying features of both hepatic pyogenic abscess and liver metastasis. These features included iso- or hypointense signaling on T1WI and T2WI, hyperintense signaling on diffusion weighted imaging of the thick wall, and mixed hyperintense signal in the center on DWI, as well as dramatic and irregular peripheral enhancement was detected on LAVA dynamic contrast scanning. Aspiration and culture of the largest lesions revealed Klebsiella pneumoniae and a pathologic diagnosis of adenocarcinoma. At this point, the patient admitted a history of colon adenocarcinoma 9 years ago treated with hemicolectomy. Therefore, this patient was considered to have a hepatic pyogenic abscesses complicated by hepatic metastasis. The patient began treatment for the responsible pathogens and underwent chemoembolization of the liver lesions. In special cases, we could attempt to pursue a more detailed search for coexistence of microorganism infection and tumor.

  11. A case of hepatocolic fistula after percutaneous drainage for a gas-containing pyogenic liver abscess.

    PubMed

    Satoh, H; Matsuyama, S; Mashima, H; Imoto, A; Hidaka, K; Hisatsugu, T

    1994-12-01

    We describe a rare case of gas-containing pyogenic liver abscess which penetrated the adjacent colon, forming a hepatocolic fistula, after percutaneous transhepatic abscess drainage (PTAD) had been performed. To the best of our knowledge, this is the first report of hepatocolic fistula associated with a gas-forming liver abscess in a diabetic patient, with radiological and surgical confirmation of the fistula.

  12. Abscess

    MedlinePlus

    ... En Español Making a Change – Your Personal Plan Hot Topics Am I in a Healthy Relationship? Who ... compress by wetting a washcloth with warm — not hot — water and placing it over the abscess for ...

  13. Lumbar spine osteomyelitis and epidural abscess formation secondary to acupuncture

    PubMed Central

    Godhania, Vinesh

    2016-01-01

    A 39-year-old male with no previous medical history presented with abdominal and low back pain. Based on clinical and radiological findings he was diagnosed with L1/L2 osteomyelitis and epidural abscess. Further history taking revealed recent use of acupuncture for treatment of mechanical back pain. The patient was treated conservatively with an extended course of antibiotics, monitored with repeat MRI scans and had a full recovery with no neurological deficit. This is the first reported case of epidural abscess formation and osteomyelitis after acupuncture in the UK. As acupuncture becomes more commonly used in western countries, it is important to be aware of this rare but serious complication. PMID:26976275

  14. Bacterial Abscess Formation Is Controlled by the Stringent Stress Response and Can Be Targeted Therapeutically.

    PubMed

    Mansour, Sarah C; Pletzer, Daniel; de la Fuente-Núñez, César; Kim, Paul; Cheung, Gordon Y C; Joo, Hwang-Soo; Otto, Michael; Hancock, Robert E W

    2016-10-01

    Cutaneous abscess infections are difficult to treat with current therapies and alternatives to conventional antibiotics are needed. Understanding the regulatory mechanisms that govern abscess pathology should reveal therapeutic interventions for these recalcitrant infections. Here we demonstrated that the stringent stress response employed by bacteria to cope and adapt to environmental stressors was essential for the formation of lesions, but not bacterial growth, in a methicillin resistant Staphylococcus aureus (MRSA) cutaneous abscess mouse model. To pharmacologically confirm the role of the stringent response in abscess formation, a cationic peptide that causes rapid degradation of the stringent response mediator, guanosine tetraphosphate (ppGpp), was employed. The therapeutic application of this peptide strongly inhibited lesion formation in mice infected with Gram-positive MRSA and Gram-negative Pseudomonas aeruginosa. Overall, we provide insights into the mechanisms governing abscess formation and a paradigm for treating multidrug resistant cutaneous abscesses.

  15. Indium-111 leukocyte scintigraphic detection of myocardial abscess formation in patients with endocarditis

    SciTech Connect

    Cerqueira, M.D.; Jacobson, A.F.

    1989-05-01

    Myocardial abscess formation in patients with bacterial endocarditis in most clinical settings, especially in patients with prosthetic valves, is a primary indicator for surgical valve replacement. We report the detection of myocardial abscesses using /sup 111/In leukocyte scintigraphy in three patients with prosthetic or native valve endocarditis and nondiagnostic echocardiograms. Leukocyte scintigraphy may allow identification of myocardial abscess formation earlier than other imaging modalities.

  16. [Infracondylar abscess formation: a rare complication of local anesthesia].

    PubMed

    Dojcinovic, I; Hugentobler, M; Richter, M

    2006-11-01

    Ninety percent of oro-facial infections arise from a dental origin. The remaining 10% are the consequence of oro-pharyngeal, cutaneous or iatrogenic problems, such as in the present case. A 24-year-old patient consulted the emergency room because of a left mandibular swelling, accompagnied by trismus. Four days earlier, extraction of the 38 was performed under inferior alveolar nerve block anesthesia. A first drainage by vestibular approach was performed under general anesthesia. Because of the absence of improvement, a CT-scan was performed and an abscess localized at the base of the condyle, surrounding the posterior margin of the mandible, very high above the lingula. Outcome was favourable after a second surgery. Formation of an abscess very high above the lingula, around the condylar neck is rarely reported in the literature. In this patient it was certainly a complication resulting from the injection of local anesthesic with a vasoconstrictor. CT-scan should be performed to guide diagnosis in the event of an unusual course after the first surgical procedure and an adequate antibiotic regimen.

  17. Cellular bases of experimental amebic liver abscess formation.

    PubMed Central

    Tsutsumi, V.; Mena-Lopez, R.; Anaya-Velazquez, F.; Martinez-Palomo, A.

    1984-01-01

    The complete sequence of morphologic events during amebic liver abscess formation in the hamster has been studied, from the lodgement of amebas in the hepatic sinusoids to the development of extensive liver necrosis. Following intraportal inoculation of live amebas, the early stages of the lesion (from 1 to 12 hours) were characterized by acute cellular infiltration composed of an increasingly large number of polymorphonuclear leukocytes, which surrounded centrally located trophozoites. Histiocytes and lysed leukocytes were situated on the periphery of the lesions. Hepatocytes close to the early lesions showed degenerative changes which led to necrosis; however, direct contact of liver cells with amebas was very rarely observed. At later stages, the extent of necrosis increased, macrophages and epithelioid cells replaced most leukocytes, and well-organized granulomas developed. Extensive necrosis associated with fused granulomas was present by Day 7. The results suggest that Entamoeba histolytica trophozoites do not produce amebic liver abscesses in hamsters through direct lysis of hepatocytes. Rather, tissue destruction is the result of the accumulation and subsequent lysis of leukocytes and macrophages surrounding the amebas. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:6385728

  18. Venous sinus thrombosis after Proteus vulgaris meningitis and concomitant Clostridium abscess formation.

    PubMed

    Bodur, Hürrem; Colpan, Aylin; Gozukucuk, Ramazan; Akinci, Esragul; Cevik, Mustafa Aydin; Balaban, Neriman

    2002-01-01

    A 19-y-old woman presented with Proteus vulgaris meningitis as a complication of chronic otitis media. Despite treatment with ceftazidime and amikacin no clinical improvement was observed. Cranial MRI revealed right-sided mastoiditis/otitis media and venous sinus thrombosis. After mastoidectomy, repeat cranial MRI demonstrated abscess formation in the venous sinuses. The abscess was drained. Clostridium spp. was isolated from the abscess culture.

  19. Mycobacterium abscessus cording prevents phagocytosis and promotes abscess formation

    PubMed Central

    Bernut, Audrey; Herrmann, Jean-Louis; Kissa, Karima; Dubremetz, Jean-François; Gaillard, Jean-Louis; Lutfalla, Georges; Kremer, Laurent

    2014-01-01

    Mycobacterium abscessus is a rapidly growing Mycobacterium causing a wide spectrum of clinical syndromes. It now is recognized as a pulmonary pathogen to which cystic fibrosis patients have a particular susceptibility. The M. abscessus rough (R) variant, devoid of cell-surface glycopeptidolipids (GPLs), causes more severe clinical disease than the smooth (S) variant, but the underlying mechanisms of R-variant virulence remain obscure. Exploiting the optical transparency of zebrafish embryos, we observed that the increased virulence of the M. abscessus R variant compared with the S variant correlated with the loss of GPL production. The virulence of the R variant involved the massive production of serpentine cords, absent during S-variant infection, and the cords initiated abscess formation leading to rapid larval death. Cording occurred within the vasculature and was highly pronounced in the central nervous system (CNS). It appears that M. abscessus is transported to the CNS within macrophages. The release of M. abscessus from apoptotic macrophages initiated the formation of cords that grew too large to be phagocytized by macrophages or neutrophils. This study is a description of the crucial role of cording in the in vivo physiopathology of M. abscessus infection and emphasizes cording as a mechanism of immune evasion. PMID:24567393

  20. Brain abscess and granuloma formation as late complications of retained ventricular catheter.

    PubMed

    Khan, S A; Gretchel, A; Govender, H; Hartzenberg, B

    2009-01-01

    This report presents a rare complication of ventriculoperitoneal shunt, delayed development of brain abscess and foreign body granuloma formation adjacent to the intraventricular catheter. Both the complications occurring in the same patient is unusual.

  1. The role of Pseudomonas aeruginosa elastase in corneal ring abscess formation in pseudomonal keratitis.

    PubMed

    Ijiri, Y; Yamamoto, T; Kamata, R; Aoki, H; Matsumoto, K; Okamura, R; Kambara, T

    1993-09-01

    In order to identify the causative factors of ring abscess, which is the characteristic feature of pseudomonal keratitis, pseudomonal endotoxin, exotoxin A, and elastase were each separately injected into guinea pig cornea. There was no formation of ring abscess. Injection of living Pseudomonas aeruginosa strains IFO3455 and Takamatsu which produce all three molecules, clearly induced ring abscess. In contrast, when heat-killed bacteria strain IFO3455 or living bacteria of the non-elastase-producing strain PA103 were injected, ring abscess was not induced. Furthermore, when living bacteria strain IFO3455 were injected with anti-elastase antibody or a protease inhibitor, ovomacroglobulin, ring abscess formation was significantly inhibited. Histological examination demonstrated that the ring abscess was a dense accumulation and aggregation of polymorphonuclear leukocytes (PMN) with debris of cells and lamellae in the deep stroma at the corneal margins, suggesting prevention of PMN migration to the central lesion. The presence of anti-elastase antibody or a specific elastase inhibitor facilitated PMN migration towards living bacteria strain IFO3455 in an in vitro model. These results indicate that pseudomonal elastase is a necessary but not sufficient factor in the formation of ring abscess in pseudomonal keratitis.

  2. Two-step procedure for complicated appendicitis with perityphlitic abscess formation.

    PubMed

    Miftaroski, Almir; Kessler, Ulf; Monnard, Etienne; Egger, Bernhard

    2017-04-19

    Optimal management of perforated appendicitis with perityphlitic phlegmon or abscess formation is controversial. The aim of the study was to assess the outcome after a two-step procedure to treat patients with perityphlitic abscess formation. We retrospectively assessed prospectively collected data from a single-centre database that included adult patients who had appendicitis and perityphlitic abscess (>=3 cm) but no generalised peritonitis, and were treated in 2007-2015. Patients underwent a two-step procedure that comprised antibiotic treatment and drainage when technically feasible (step 1) followed by interval appendectomy (step 2). We evaluated treatment modalities, complications and outcomes. Out of a total of 1480 patients with appendicitis, 15 patients presented with perityphlitic abscess. In addition to antibiotic treatment, computed tomography-guided drainage was performed in 12 of these cases. Step 1 and 2 hospital stays were (median, range) 7 days (5–14 days) and 2 days (2–12 days), respectively. One patient’s abscess recurred after 2 months, associated with new onset appendicitis and perforation. Another patient underwent reoperation after interval appendectomy for suspected postoperative peritonitis. This two-step procedure for appendicitis with appendicular abscess was highly successful (100%) with a low rate of complications (13%). In the view of a potentially increased rate of appendicular neoplasm in combination with abscess formation, the role of interval appendectomy has to be evaluated in larger trials.

  3. Secondary abscess formation in pituitary adenoma after tooth extraction. Case report.

    PubMed

    Kroppenstedt, S N; Liebig, T; Mueller, W; Gräf, K J; Lanksch, W R; Unterberg, A W

    2001-02-01

    The presence of an abscess in a pituitary tumor is a very rare finding. The authors report the case of a 69-year-old man with a pituitary adenoma confirmed by neuroimaging results, in whom a high fever, meningismus, and left-sided ophthalmoplegia developed 4 days after tooth extraction. The results of serial cranial magnetic resonance imaging were highly indicative of an abscess formation within the pituitary adenoma. During surgery the tumor was approached transsphenoidally and removed. Histological examination confirmed the presence of an abscess formation within the pituitary adenoma. It is most likely that the tooth extraction caused a bacteremia, which led to an inflammation with abscess formation within the pituitary adenoma. The authors conclude that invasive dental procedures should be avoided before planned resection of a pituitary adenoma.

  4. Bacterial brain abscess formation in post-irradiated patients: What is the possible pathogenesis?

    PubMed

    Chuang, Jimmy Ming-Jung; Lin, Wei-Che; Fang, Fu-Min; Huang, Yu-Jie; Ho, Jih-Tsun; Lu, Cheng-Hsien

    2015-09-01

    Until recently, post-radiotherapy brain abscess was considered rare, but it has become an increasingly important aetiology. Discussions of the relationship between bacterial brain abscess and radiotherapy (RT) are rare in the literature. Our clinical study was conducted to analyse the role of RT in the pathogenesis of bacterial brain abscess. For our retrospective study, 146 patients with bacterial brain abscess were recruited. Ten patients with a history of RT before brain abscess formation were reviewed. Eight of these patients underwent RT treatment for nasopharyngeal carcinoma, one for olfactory neuroblastoma, and another for nasal plasmacytoma. Three showed presence of temporal lobe radiation necrosis neighbouring abscess. Eight patients were shown to have the evidence of tumour invasion. Seven had evidence of nasal infection or otitis media. Statistically significant differences between the RT and non-RT patients were observed for radionecrosis, bone defects between the middle fossa/sphenoid sinus, and the presence of nasal infection/otitis media. The mortality rate was 30%. This study shows possible pathogenesis of bacterial brain abscess formation in post-irradiated patients, which is complicated by both radiation effects and tumour effects. Skull base deficits (either from tumour erosion or osteonecrosis) and nasal/ear infection were significantly different in patients who received radiation vs. those who did not. Radiation-related temporal lobe necrosis was also a predisposing factor. Further study based on a proper patient cohort is warranted. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Role of T Lymphocytes in Liver Abscess Formation by Bacteroides fragilis in Mice ▿

    PubMed Central

    Chung, Doo Ryeon; Park, Hye-Rim; Park, Chung-Gyu; Hwang, Eung-Soo; Cha, Chang-Yong

    2011-01-01

    The underlying mechanisms of liver abscess formation have not been fully elucidated with regard to the interaction between bacterial virulence factors and the immune response. The objective of this study was to determine the role of the host T cells in liver abscess formation caused by Bacteroides fragilis. We developed a liver abscess mouse model with inoculation of B. fragilis through the hepatic portal vein and examined the role of T cells by studying T cell-deficient mice, as well as conducting adoptive T cell transfer experiments. No microabscess was formed in the αβ T cell receptor-positive (αβTCR+) T cell-depleted mice, in contrast to the results for the control mice. In addition, the αβTCR knockout (KO) mice showed significantly lower numbers of microabscesses, and the abscesses were smaller in size than those in the wild-type mice. Adoptive transfer of T cells purified from the wild-type mice into the αβTCR KO mice resulted in liver abscess formation in those mice. These findings suggest that T cells play an essential role in liver abscess formation caused by B. fragilis in mice. PMID:21444668

  6. An Intracranial Petri Dish? Formation of Abscess in Prior Large Stroke After Decompressive Hemicraniectomy.

    PubMed

    Wang, Jieqi; Fraser, Justin F

    2015-11-01

    Development of brain abscess after an infarction is a rare clinical condition. There have been 11 cases in the literature. Many patients were treated with potent antibiotics only and did not survive. We present 2 cases in which patients received aggressive surgical resection of brain abscess and survived. The analysis of the literature confirmed our finding that surgical intervention of brain abscess in patients after stroke is advisable. A 58-year-old man was transferred to our institution with left hemiparesis, hemisensory loss, neglect, and hemianopsia. The computed tomography angiography demonstrated large volume right hemispheric infarct. He underwent decompressive hemicraniectomy but developed fevers and swollen fontanelle 6 weeks later, which did not improve with antibiotics. The magnetic resonance imaging demonstrated progression of ring-enhancement of the old infarct and abscess formation was suspected. In another case, a 42-year-old woman was admitted to our institution with aphasia and weakness on the right side. The computed tomography angiography showed left middle cerebral artery territory infarction and decompressive hemicraniectomy was performed. Patient recovered well but a brain abscess was suspected during a routine preoperative computed tomography before cranioplasty. In the first case, patient was then taken to the operating room for resection of the infarcted brain tissue involved. The patient's consciousness improved, and he was discharged with antibiotic treatment. The patient subsequently underwent cranioplasty with synthetic graft with no complications. In the second case, the suspected abscess was resected surgically and culture of abscess grew Pantoea agglomerans and Bacillus macerans. The patient underwent synthetic cranioplasty 1 month later and remained in good condition. Secondary abscess formation after significant ischemic stroke is a rare condition that carries potential for high morbidity/mortality. The limited body of literature

  7. Gas-forming liver abscess associated with rapid hemolysis in a diabetic patient

    PubMed Central

    Kurasawa, Miwa; Nishikido, Takashi; Koike, Junko; Tominaga, Shin-ichi; Tamemoto, Hiroyuki

    2014-01-01

    We experienced a case of liver abscess due to Clostridium perfringens (CP) complicated with massive hemolysis and rapid death in an adequately controlled type 2 diabetic patient. The patient died 6 h after his first visit to the hospital. CP was later detected in a blood culture. We searched for case reports of CP septicemia and found 124 cases. Fifty patients survived, and 74 died. Of the 30 patients with liver abscess, only 3 cases survived following treatment with emergency surgical drainage. For the early detection of CP infection, detection of Gram-positive rods in the blood or drainage fluid is important. Spherocytes and ghost cells indicate intravascular hemolysis. The prognosis is very poor once massive hemolysis occurs. The major causative organisms of gas-forming liver abscess in diabetic patients are Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli). Although CP is relatively rare, the survival rate is very poor compared with those of K. pneumoniae and E. coli. Therefore, for every case that presents with a gas-forming liver abscess, the possibility of CP should be considered, and immediate aspiration of the abscess and Gram staining are important. PMID:24748935

  8. Vaginocutaneous fistula and buttock abscess formation 7 years after polypropylene transobturator tape insertion.

    PubMed

    Abdallah, A; Nisolle, M; de Landsheere, L

    2017-01-01

    Surgical treatment for stress urinary incontinence (SUI) using transobturator tape insertion is widely accepted. However, several postoperative complications were reported in the literature including infections, abscess and fistula formation. Here, we report a case of 57-year-old female who presented with abscess and left vaginocutaneous buttock fistula 7 years after transobturator polypropylene tape insertion. Treatment included abscess drainage with dissection of the fistulous tract and removal of the left arm of the transobturator tape along with antibiotic coverage. Sinus drainage stopped after 3 days. Stress urinary incontinence did not recur. Suspicion of fistula formation should rise in patients presenting with bothersome vaginal or cutaneous discharge after transobturator tape insertion. This case is particular since it describes a fistula complication with polypropylene tape, which is unusual with this type of tapes. Treatment of such complication should always consist of surgical removal of the mesh to allow closure of the fistulous tract. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  9. Abscess formation after lip augmentation with silicone: case report.

    PubMed

    Schmidt-Westhausen, A M; Frege, J; Reichart, P A

    2004-03-01

    This paper describes the development of an abscess after injection of an alloplastic preparation (silicone) for enhancement of the lower lip. The 56-year-old woman presented with a painful swelling of her lower lip which was incised. Pus drained from the incision. A biopsy was taken. Histology revealed homogeneous foreign body inclusions (silicone) with fibrosis, chronic inflammation and multinuclear giant cells. Healing was uneventful with little deformation of the lower lip. Since the number of persons seeking aesthetic lip augmentation is increasing, oral surgeons and dentists should be familiar with adverse effects to filling agents.

  10. Pancreatic and Colonic Abscess Formation Secondary to HELLP Syndrome

    PubMed Central

    Fumia, Fred

    2015-01-01

    Preeclampsia and the variant HELLP syndrome are systemic conditions associated with vascular changes resulting in vasoconstriction. Most commonly, patients present with elevated blood pressure and proteinuria, with a background of complaints such as headache, scotoma, and right upper quadrant pain. The systemic vascular changes experienced can target any organ system, oftentimes with more than one organ system being involved. We present the case of a patient admitted with HELLP syndrome who subsequently developed multisystem organ dysfunction, including placental abruption, disseminated intravascular coagulopathy, acute renal failure, colitis, abdominal ascites, pancreatitis, and the development of pancreatic and colonic abscesses. PMID:26064725

  11. Multiple psoas abscess formation after pharmacopuncture -a case report-.

    PubMed

    Koo, Eun Hye; Choi, Sang Sik; Chung, Dong Hun; Lee, Il Ok; Kim, Nan Sook; Lim, Sang Ho

    2010-12-01

    Acupuncture has been widely used in alternative medicine for pain relief but may have many complications due to lack of appropriate cares. Pharmacopuncture is a sort of acupuncture that injects a herbal ingredient through a thin tube for the purpose of combining the effects of the herb and acupuncture and it has many pitfalls. The agents used in pharmacopuncture are not refined for a desired effect and not produced by sterile standard processes under strict medical surveillance. We report a case of a 44-yr-old male patient who had multiple abscesses in the psoas region with fever, right low back and hip pain that began after the pharmacopuncture treatment. This case shows that although pharmacopuncture has been practiced widely, it is important that the appropriate aseptic technique should be used to prevent severe infections and other complications.

  12. [A patient with sepsis and a gas-forming liver abscess caused by Clostridium perfringens treated with continuous perfusion drainage].

    PubMed

    Kusumoto, Kiyonori; Hamada, Akihiko; Kusaka, Toshihiro; Yamaguchi, Daisuke; Yoshioka, Takuto; Nakai, Yoshitaka; Matsubara, Susumu; Azechi, Hidemasa; Fujii, Shigehiko; Kokuryu, Hiroyuki

    2014-07-01

    A 64-year-old man presented with diarrhea, fever, and disturbance of consciousness; he was subsequently diagnosed with acute renal and hepatic disorder. Abdominal computed tomography identified a gas-forming liver abscess, and the patient underwent emergency drainage. However, his condition did not improve, and Clostridium perfringens was observed in his blood culture. Continuous perfusion drainage was performed by placing an additional drainage tube, which resulted in abscess shrinkage and improved the patient's general condition. Despite the low survival rate in patients with gas-forming liver abscesses caused by C. perfringens, therapy was successful in this patient.

  13. Hypoxia-Inducible Factor 1-Regulated Lysyl Oxidase Is Involved in Staphylococcus aureus Abscess Formation

    PubMed Central

    Beerlage, Christiane; Greb, Jessica; Kretschmer, Dorothee; Assaggaf, Mohammad; Trackman, Philip C.; Hansmann, Martin-Leo; Bonin, Michael; Eble, Johannes A.; Peschel, Andreas; Brüne, Bernhard

    2013-01-01

    Hypoxia-inducible factor 1 (HIF-1) is the key transcription factor involved in the adaptation of mammals to hypoxia and plays a crucial role in cancer angiogenesis. Recent evidence suggests a leading role for HIF-1 in various inflammatory and infectious diseases. Here we describe the role of HIF-1 in Staphylococcus aureus infections by investigating the HIF-1-dependent host cell response. For this purpose, transcriptional profiling of HIF-1α-deficient HepG2 and control cells, both infected with Staphylococcus aureus, was performed. Four hours after infection, the expression of 190 genes, 24 of which were regulated via HIF-1, was influenced. LOX (encoding lysyl oxidase) was one of the upregulated genes with a potential impact on the course of S. aureus infection. LOX is an amine oxidase required for biosynthetic cross-linking of extracellular matrix components. LOX was upregulated in vitro in different cell cultures infected with S. aureus and also in vivo, in kidney abscesses of mice intravenously infected with S. aureus and in clinical skin samples from patients with S. aureus infections. Inhibition of LOX by β-aminopropionitrile (BAPN) did not affect the bacterial load in kidneys or blood but significantly influenced abscess morphology and collagenization. Our data provide evidence for a crucial role of HIF-1-regulated LOX in abscess formation. PMID:23649089

  14. Use of Prophylactic Antibiotics to Prevent Abscess Formation Following Hepatic Ablation in Patients with Prior Enterobiliary Manipulation.

    PubMed

    Odisio, Bruno C; Richter, Michael; Aloia, Thomas A; Conrad, Claudius; Ahrar, Kamran; Gupta, Sanjay; Vauthey, Jean-Nicolas; Huang, Steven Y

    2016-08-01

    Prior enterobiliary manipulation confers a high risk for liver abscess formation after hepatic ablation. We aimed to determine if prophylactic antibiotics could prevent post-ablation abscess in patients with a history of hepaticojejunostomy. This single-institution retrospective study identified 262 patients who underwent 307 percutaneous liver ablation sessions between January 2010 and August 2014. Twelve (4.6 %) patients with prior hepaticojejunostomy were included in this analysis. Ten (83> %) had received an aggressive prophylactic antibiotic regimen consisting of levofloxacin, metronidazole, neomycin, and erythromycin base. Two (16.6 %) had received other antibiotic regimens. Clinical, laboratory, and imaging findings were used to identify abscess formation and antibiotic-related side effects. Twelve ablation sessions were performed during the period studied. During a mean follow-up period of 440 days (range, 77-1784 days), post-ablation abscesses had developed in 2 (16.6 %) patients, who both received the alternative antibiotic regimens. None of the 10 patients who received the aggressive prophylactic antibiotic regimen developed liver abscess. One of the 10 patients who received the aggressive prophylactic antibiotic regimen developed grade 2 antibiotic-related diarrhea and arthralgia. An aggressive regimen of prophylactic antibiotics may be effective in preventing liver abscess formation after liver ablation in patients with prior hepaticojejunostomy.

  15. Skin abscess

    MedlinePlus

    Abscess - skin; Cutaneous abscess; Subcutaneous abscess; MRSA - abscess; Staph infection - abscess ... have methicillin-resistant Staphylococcus aureus (MRSA) or another staph infection, follow instructions for self-care at home.

  16. Propionibacterium acnes prosthetic valve endocarditis with abscess formation: a case report

    PubMed Central

    2014-01-01

    Background Endocarditis due to Propionibacterium acnes is a rare disease. Scant data on treatment of these infections is available and is based on case reports only. If the disease is complicated by abscess formation, surgical intervention combined with an antibiotic therapy might improve clinical outcome. In some cases, cardiac surgeons are reluctant to perform surgery, since they consider the intervention as high risk. Therefore, a conservative therapy is required, with little, if any evidence to choose the optimal antibiotic. We report the first case of a successfully treated patient with P. acnes prosthetic valve endocarditis without surgery. Case presentation We report the case of a 29-year-old patient with a prosthetic valve endocarditis and composite graft infection with abscess formation of the left ventricular outflow tract due to P. acnes. Since cardiac surgery was considered as high risk, the patient was treated intravenously with ceftriaxone 2 g qd and rifampin 600 mg bid for 7 weeks and was switched to an oral therapy with levofloxacin 500 mg bid and rifampin 600 mg bid for an additional 6 months. Two sets of blood cultures collected six weeks after completion of treatment remained negative. The patient is considered to be cured based on absence of clinical signs and symptoms, normal laboratory parameters, negative radiology scans and negative blood cultures, determined at site visits over two years after completion of treatment. Conclusion To our knowledge, this is the first successfully managed patient with P. acnes prosthetic valve endocarditis with abscess formation of the left ventricular outflow tract who was treated with antibiotics alone without a surgical intervention. A six month treatment with a rifampin and levofloxacin combination was chosen, based on the excellent activity against stationary-phase and adherent bacteria. PMID:24568204

  17. Risk factors for liver abscess formation in patients with blunt hepatic injury after non-operative management.

    PubMed

    Hsu, C-P; Wang, S-Y; Hsu, Y-P; Chen, H-W; Lin, B-C; Kang, S-C; Yuan, K-C; Liu, E-H; Kuo, I-M; Liao, C-H; Ouyang, C-H; Yang, S-J

    2014-10-01

    To identify risk factors for liver abscess formation in patients with blunt hepatic injury who underwent non-operative management (NOM). From January 2004 to October 2008, retrospective data were collected from a single level I trauma center. Clinical data, hospital course, and outcome were all extracted from patient medical records for further analysis. A total of 358 patients were enrolled for analysis. There were 13 patients with liver abscess after blunt hepatic injury. Patients with abscess had a significant increase in glutamic oxaloacetic transaminase (GOT, p = 0.006) and glutamic pyruvic transaminase (GPT, p < 0.0001), and a decrease in arterial blood pH (p = 0.023) compared to patients without abscess in the univariate analyses. In addition, high-grade hepatic injury and transarterial embolization (TAE, p < 0.001) were also risk factors for liver abscess formation. Five factors (GOT, GPT, pH level in the arterial blood sample, TAE, and high-grade hepatic injury) were included in the multivariate analysis. TAE, high-grade hepatic injury, and GPT level were statistically significant. The odds ratios of TAE and high-grade hepatic injury were 15.41 and 16.08, respectively. A receiver operating characteristic (ROC) analysis was used for GPT, and it suggested cutoff values of 372.5 U/L. A prediction model based on the ROC analysis had 100 % sensitivity and 86.7 % specificity to predict liver abscess formation in patients with two of the three independent risk factors. TAE, high-grade hepatic injury, and a high GPT level are independent risk factors for liver abscess formation.

  18. Gliomas with intratumoral abscess formation: Description of new cases, review of the literature, and the role of (99m)TC-Leukoscan.

    PubMed

    Campennì, Alfredo; Caruso, Gerardo; Barresi, Valeria; Pino, Mariangela; Cucinotta, Mariapaola; Baldari, Sergio; Caffo, Maria

    2015-07-01

    Abscess formation within a brain tumor is uncommon. Intrasellar or parasellar tumors are the most common neoplasms that develop such complications. Cerebral gliomas with abscesses are extremely rare. In this paper three rare cases of glioma associated with abscess formation are described. The diagnosis of brain tumor associated with abscess is particularly difficult by conventional neuroradiological studies. (99m)Tc-labeled sulesomab can be useful in the diagnosis of brain tumors with intratumoral abscesses. There are no precise guidelines for the diagnosis and treatment of cerebral gliomas associated with abscesses formation for the low number of cases reported to date. Appropriate treatment, aimed at radical surgery, and a suitable antibiotic-protocol, deferring adjuvant postoperative therapy, is associated with a more favorable outcome. A review of the pertinent literature is also performed. Copyright © 2015. Published by Elsevier Taiwan.

  19. Rapid gas hydrate formation process

    DOEpatents

    Brown, Thomas D.; Taylor, Charles E.; Unione, Alfred J.

    2013-01-15

    The disclosure provides a method and apparatus for forming gas hydrates from a two-phase mixture of water and a hydrate forming gas. The two-phase mixture is created in a mixing zone which may be wholly included within the body of a spray nozzle. The two-phase mixture is subsequently sprayed into a reaction zone, where the reaction zone is under pressure and temperature conditions suitable for formation of the gas hydrate. The reaction zone pressure is less than the mixing zone pressure so that expansion of the hydrate-forming gas in the mixture provides a degree of cooling by the Joule-Thompson effect and provides more intimate mixing between the water and the hydrate-forming gas. The result of the process is the formation of gas hydrates continuously and with a greatly reduced induction time. An apparatus for conduct of the method is further provided.

  20. Hematoma and abscess formation caused by Mycoplasma hominis following cesarean section

    PubMed Central

    Koshiba, Hisato; Koshiba, Akemi; Daimon, Yasushi; Noguchi, Toshifumi; Iwasaku, Kazuhiro; Kitawaki, Jo

    2011-01-01

    Mycoplasma species cannot be identified by routine bacteriological culture methods and are resistant to common antimicrobial agents. Mycoplasma hominis usually colonizes the lower urogenital tract and causes pyelonephritis, pelvic inflammatory disease, chorioamnionitis, rupture of fetal membranes, preterm labor, postpartum fever, postabortal fever, and neonatal infection. This organism is highly prevalent in cervicovaginal cultures of sexually active women. M. hominis, M. genitalis, Ureaplasma urealyticum, and U. parvum may invade and infect placental and fetal tissues, leading to adverse pregnancy outcomes. M. hominis occasionally causes nongenitourinary infection of the blood, wounds, central nervous system, joints, or respiratory tract. We present a case of a 27-year-old woman who developed abdominal wound hematoma and abscess after cesarean section. The wound was drained, but her high fever persisted, in spite of antibiotic treatment using flomoxef sodium and imipenem·cilastatin sodium. Because the exudate exhibited M. hominis growth in an anaerobic environment, we administered the quinolone ciprofloxacin. This therapy resolved her fever, and her white blood cell count and C-reactive protein level diminished to the normal ranges. To our knowledge, there are four published articles regarding the isolation of M. hominis from postcesarean incisions. Based on the current study and the literature, infection by this pathogen may cause hematoma formation with or without abscess after cesarean section or in immunosuppressed postoperative patients. In such cases, physicians may need to suspect Mycoplasma infection and initiate appropriate antibacterial treatment as soon as possible in order to avoid persistent fever. PMID:21339933

  1. Brain abscess

    MedlinePlus

    ... with certain heart disorders, may receive antibiotics before dental or other procedures to help reduce the risk of infection. Alternative Names Abscess - brain; Cerebral abscess; CNS abscess Patient Instructions Brain surgery - discharge Images Amebic brain abscess ...

  2. Neutrophil-derived IL-1β Is Sufficient for Abscess Formation in Immunity against Staphylococcus aureus in Mice

    PubMed Central

    Cho, John S.; Guo, Yi; Ramos, Romela Irene; Hebroni, Frank; Plaisier, Seema B.; Xuan, Caiyun; Granick, Jennifer L.; Matsushima, Hironori; Takashima, Akira; Iwakura, Yoichiro; Cheung, Ambrose L.; Cheng, Genhong; Lee, Delphine J.; Simon, Scott I.; Miller, Lloyd S.

    2012-01-01

    Neutrophil abscess formation is critical in innate immunity against many pathogens. Here, the mechanism of neutrophil abscess formation was investigated using a mouse model of Staphylococcus aureus cutaneous infection. Gene expression analysis and in vivo multispectral noninvasive imaging during the S. aureus infection revealed a strong functional and temporal association between neutrophil recruitment and IL-1β/IL-1R activation. Unexpectedly, neutrophils but not monocytes/macrophages or other MHCII-expressing antigen presenting cells were the predominant source of IL-1β at the site of infection. Furthermore, neutrophil-derived IL-1β was essential for host defense since adoptive transfer of IL-1β-expressing neutrophils was sufficient to restore the impaired neutrophil abscess formation in S. aureus-infected IL-1β-deficient mice. S. aureus-induced IL-1β production by neutrophils required TLR2, NOD2, FPR1 and the ASC/NLRP3 inflammasome in an α-toxin-dependent mechanism. Taken together, IL-1β and neutrophil abscess formation during an infection are functionally, temporally and spatially linked as a consequence of direct IL-1β production by neutrophils. PMID:23209417

  3. Tuberculous spondylitis and paravertebral abscess formation after kyphoplasty: a case report.

    PubMed

    Ivo, Roland; Sobottke, Rolf; Seifert, Harald; Ortmann, Monika; Eysel, Peer

    2010-05-20

    Case report. To report a patient with spinal tuberculosis (TB) and paravertebral abscess formation after kyphoplasty of L1. The literature is reviewed, and diagnostic options are discussed. Kyphoplasty is a well-established procedure in the treatment of osteoporotic compression fractures and metastatic tumors of the vertebrae. Although complication rates are low, there is evidence for an increased risk of serious local infections after kyphoplasty in patients with any history of systemic infection. Spinal TB accounts for 2% of all TB cases with a trend toward an increased incidence in parallel with the growing number of immunocompromised patients. To our knowledge, only 1 article had reported a patient suffering from Pott disease after vertebroplasty. A 70-year-old patient with compression fracture of L1 underwent percutaneous kyphoplasty using polymethyl methacrylate. Two weeks after kyphoplasty, the patient was readmitted with backache and signs of acute infection. Magnetic resonance imaging confirmed the diagnosis of spondylitis with paravertebral abscess formation. A tissue specimen obtained by computed tomography-guided percutaneous biopsy did not yield any pathogen. As broad-spectrum antibiotic therapy failed, combined surgery consisting of posterior instrumentation of Th11-L3 and anterior debridement, corporectomy of L1, and interposition of a titanium mesh cage filled with autologous rib graft was performed. Histologic examination of resected tissue and PCR and culture results confirmed diagnosis of spinal TB. Despite adequate antibiotic treatment and local surgical interventions, the patient died from septic multiple organ failure. Indication for kyphoplasty in patients with any history of local or systemic infection should be scrutinized rigorously. Symptoms of spinal TB are often nonspecific, and the clinician should be aware of this entity. Active investigation including microbiological and histologic examination is of utmost importance to avoid any

  4. Enterobius vermicularis: Can it be a possible pathogen in Bartholin gland abscess formation?

    PubMed

    Dönmez, Melahat Emine; Özlü, Tülay; Yılmaz, Fahri; Ayaz, Erol

    2014-01-01

    The most frequent disorders of the Bartholin glands are cysts or abscesses. Bartholin gland abscesses occur generally as a result of polymicrobial infections or agents that cause sexually transmitted diseases. But as far as we know, no parasite has been previously reported among the infectious agents that are detected from the abscesses of the Bartholin gland. Here, we report a 45-year-old woman, in the Bartholin abscess aspirate of whom Enterobius vermicularis eggs were detected in between the inflammatory infiltrate by cytological examination. © 2013 The Authors. Journal of Obstetrics and Gynaecology Research © 2013 Japan Society of Obstetrics and Gynecology.

  5. A Case Series of Liver Abscess Formation after Transcatheter Arterial Chemoembolization for Hepatic Tumors

    PubMed Central

    Sun, Wei; Xu, Fei; Li, Xiao; Li, Chen-Rui

    2017-01-01

    Background: Liver abscess is a serious complication following transcatheter arterial chemoembolization (TACE). Much attention has been paid to this condition as it may interfere with the treatment process and result in a poor prognosis of the patient. This study aimed to analyze the causes of liver abscess, a complication, after TACE for hepatic tumors and to summarize management approaches. Methods: From June 2012 to June 2014, of 1480 consecutive patients who underwent TACE at our hospital, five patients developed liver abscess after TACE procedures for hepatic tumors. Of the five patients, each receiving conventional TACE, one underwent three sessions, two underwent two sessions, and the remaining two underwent one session of TACE. Demographic and clinical characteristics, together with management approaches and prognosis, were collected through a review of medical records. Results: These five patients were confirmed to have post-TACE liver abscess through clinical manifestations, laboratory, and imaging tests. After percutaneous drainage and anti-inflammatory treatments, the symptoms present in four patients with liver abscess significantly improved as evidenced by shrinkage or disappearance of the abscess cavity, and the patients recovered completely after sufficient drainage. The remaining patient experienced recurrent symptoms and abdominal abscess, achieved no significant improvement after treatment, and eventually died of severe infection and multiple organ failures. Conclusions: TACE must be implemented with extreme caution to avoid liver abscess. An effective management relies on an early diagnosis, prompt use of sufficient doses of appropriate antibiotics, and active implementation of abscess incision, drainage, and aspiration. PMID:28524831

  6. A Case Series of Liver Abscess Formation after Transcatheter Arterial Chemoembolization for Hepatic Tumors.

    PubMed

    Sun, Wei; Xu, Fei; Li, Xiao; Li, Chen-Rui

    2017-06-05

    Liver abscess is a serious complication following transcatheter arterial chemoembolization (TACE). Much attention has been paid to this condition as it may interfere with the treatment process and result in a poor prognosis of the patient. This study aimed to analyze the causes of liver abscess, a complication, after TACE for hepatic tumors and to summarize management approaches. From June 2012 to June 2014, of 1480 consecutive patients who underwent TACE at our hospital, five patients developed liver abscess after TACE procedures for hepatic tumors. Of the five patients, each receiving conventional TACE, one underwent three sessions, two underwent two sessions, and the remaining two underwent one session of TACE. Demographic and clinical characteristics, together with management approaches and prognosis, were collected through a review of medical records. These five patients were confirmed to have post-TACE liver abscess through clinical manifestations, laboratory, and imaging tests. After percutaneous drainage and anti-inflammatory treatments, the symptoms present in four patients with liver abscess significantly improved as evidenced by shrinkage or disappearance of the abscess cavity, and the patients recovered completely after sufficient drainage. The remaining patient experienced recurrent symptoms and abdominal abscess, achieved no significant improvement after treatment, and eventually died of severe infection and multiple organ failures. TACE must be implemented with extreme caution to avoid liver abscess. An effective management relies on an early diagnosis, prompt use of sufficient doses of appropriate antibiotics, and active implementation of abscess incision, drainage, and aspiration.

  7. Star formation and gas supply

    NASA Astrophysics Data System (ADS)

    Catinella, B.

    2016-06-01

    A detailed knowledge of how gas cycles in and around galaxies, and how it depends on galaxy properties such as stellar mass and star formation rate, is crucial to understand galaxy formation and evolution. We take advantage of the most sensitive surveys of cold gas in massive galaxies, GASS and COLD GASS, as well as of the state-of-the-art HI blind survey ALFALFA to investigate how molecular and atomic hydrogen reservoirs vary along and across the main sequence of star-forming galaxies.

  8. Synergistic Effect of Combined Hollow Viscus Injuries on Intra-Abdominal Abscess Formation.

    PubMed

    Paulus, Elena M; Croce, Martin A; Shahan, Charles P; Zarzaur, Ben L; Sharpe, John P; Dileepan, Amirtha; Boyd, Brandon S; Fabian, Timothy C

    2015-07-01

    The strong association between penetrating colon injuries and intra-abdominal abscess (IAA) formation is well established and attributed to high colon bacterial counts. Since trauma patients are rarely fasting at injury, stomach and small bowel colony counts are also elevated. We hypothesized that there is a synergistic effect of increased IAA formation with concomitant stomach and/or colon injuries when compared to small bowel injuries alone. Consecutive patients at a level one trauma center with penetrating small bowel (SB), stomach (S), and/or colon (C) injuries from 1996 to 2012 were reviewed. Logistic regression determined associations with IAA, adjusting for age, gender, Injury Severity Score (ISS), admission Glasgow Coma Score, transfusions, and concurrent pancreas or liver injury. A total of 1518 patients (91% male, ISS = 15.9 ± 8.4) were identified: 496 (33%) SB, 231 (15%) S, 288 (19%) C, 40 (3%) S + SB, 69 (5%) S + C, 338 (22%) C + SB, and 56 (4%) S + C + SB. 148 (10%) patients developed IAA: 4 per cent SB, 9 per cent S, 10 per cent C, 5 per cent S + SB, 22 per cent S + C, 13 per cent C + SB, and 25 per cent S + C + SB. Multiple logistic regression demonstrated that ISS, 24 hour blood transfusions, and concomitant pancreatic or liver injuries were associated with IAA. Compared with reference SB, S or S + SB injuries were no more likely to develop IAA. However, S + C, SB + C, and S + C + SB injuries were significantly more likely to have IAA. In conclusion, combined stomach + colon, small bowel + colon, and stomach, colon, + small bowel injuries have a synergistic effect leading to increased IAA formation after penetrating injuries. Heightened clinical suspicion for IAA formation is necessary in these combined hollow viscus injury patients.

  9. Biliopancreatic fistula and abscess formation in the bursa omentalis associated with intraductal papillary mucinous cancer of the pancreas.

    PubMed

    Nagano, Hideki; Koneri, Kenji; Honda, Kei; Murakami, Makoto; Hirono, Yasuo; Maeda, Hiroyuki; Goi, Takanori; Iida, Atsushi; Katayama, Kanji; Yamaguchi, Akio

    2009-10-01

    We describe an unusual case of biliopancreatic fistula, free perforation, and subsequent abscess formation within the lesser peritoneal sac associated with intraductal papillary mucinous carcinoma (IPMC). A 71-year-old man presented with general fatigue and loss of appetite that had persisted for 1 month. Abdominal computed tomography (CT) revealed findings consistent with an intraductal papillary mucinous neoplasm (IPMN) of the pancreas, accompanied by abscess formation in the bursa omentalis. Gastrointestinal fiberscopy revealed a swollen papilla of Vater expanded by sticky mucus, and a communication between the pancreatic duct and bile duct was demonstrated by the injection of indigo carmine solution into the pancreatic duct. Percutaneous transhepatic abscess drainage (PTAD) was performed on the day of admission. After this procedure, the patient was managed for 1 month and supported nutritionally with glycemic control for diabetes mellitus. After admission, the patient had an episode of obstructive jaundice that was treated by retrograde biliary drainage. Pancreaticoduodenectomy with lymph node dissection was then performed. Pathological examination revealed IPMN with patchy, scattered carcinoma of the pancreatic head and uncinate process with the formation of a biliopancreatic fistula. Bile duct epithelium in the area of the biliopancreatic fistula demonstrated atypical papillary epithelium suggestive of tumor invasion.

  10. Natural mutations in a Staphylococcus aureus virulence regulator attenuate cytotoxicity but permit bacteremia and abscess formation

    PubMed Central

    Das, Sudip; Lindemann, Claudia; Young, Bernadette C.; Muller, Julius; Österreich, Babett; Ternette, Nicola; Winkler, Ann-Cathrin; Paprotka, Kerstin; Reinhardt, Richard; Allen, Elizabeth; Flaxman, Amy; Yamaguchi, Yuko; Rollier, Christine S.; van Diemen, Pauline; Blättner, Sebastian; Remmele, Christian W.; Selle, Martina; Dittrich, Marcus; Müller, Tobias; Vogel, Jörg; Ohlsen, Knut; Crook, Derrick W.; Massey, Ruth; Wilson, Daniel J.; Rudel, Thomas; Wyllie, David H.; Fraunholz, Martin J.

    2016-01-01

    Staphylococcus aureus is a major bacterial pathogen, which causes severe blood and tissue infections that frequently emerge by autoinfection with asymptomatically carried nose and skin populations. However, recent studies report that bloodstream isolates differ systematically from those found in the nose and skin, exhibiting reduced toxicity toward leukocytes. In two patients, an attenuated toxicity bloodstream infection evolved from an asymptomatically carried high-toxicity nasal strain by loss-of-function mutations in the gene encoding the transcription factor repressor of surface proteins (rsp). Here, we report that rsp knockout mutants lead to global transcriptional and proteomic reprofiling, and they exhibit the greatest signal in a genome-wide screen for genes influencing S. aureus survival in human cells. This effect is likely to be mediated in part via SSR42, a long-noncoding RNA. We show that rsp controls SSR42 expression, is induced by hydrogen peroxide, and is required for normal cytotoxicity and hemolytic activity. Rsp inactivation in laboratory- and bacteremia-derived mutants attenuates toxin production, but up-regulates other immune subversion proteins and reduces lethality during experimental infection. Crucially, inactivation of rsp preserves bacterial dissemination, because it affects neither formation of deep abscesses in mice nor survival in human blood. Thus, we have identified a spontaneously evolving, attenuated-cytotoxicity, nonhemolytic S. aureus phenotype, controlled by a pleiotropic transcriptional regulator/noncoding RNA virulence regulatory system, capable of causing S. aureus bloodstream infections. Such a phenotype could promote deep infection with limited early clinical manifestations, raising concerns that bacterial evolution within the human body may contribute to severe infection. PMID:27185949

  11. Natural mutations in a Staphylococcus aureus virulence regulator attenuate cytotoxicity but permit bacteremia and abscess formation.

    PubMed

    Das, Sudip; Lindemann, Claudia; Young, Bernadette C; Muller, Julius; Österreich, Babett; Ternette, Nicola; Winkler, Ann-Cathrin; Paprotka, Kerstin; Reinhardt, Richard; Förstner, Konrad U; Allen, Elizabeth; Flaxman, Amy; Yamaguchi, Yuko; Rollier, Christine S; van Diemen, Pauline; Blättner, Sebastian; Remmele, Christian W; Selle, Martina; Dittrich, Marcus; Müller, Tobias; Vogel, Jörg; Ohlsen, Knut; Crook, Derrick W; Massey, Ruth; Wilson, Daniel J; Rudel, Thomas; Wyllie, David H; Fraunholz, Martin J

    2016-05-31

    Staphylococcus aureus is a major bacterial pathogen, which causes severe blood and tissue infections that frequently emerge by autoinfection with asymptomatically carried nose and skin populations. However, recent studies report that bloodstream isolates differ systematically from those found in the nose and skin, exhibiting reduced toxicity toward leukocytes. In two patients, an attenuated toxicity bloodstream infection evolved from an asymptomatically carried high-toxicity nasal strain by loss-of-function mutations in the gene encoding the transcription factor repressor of surface proteins (rsp). Here, we report that rsp knockout mutants lead to global transcriptional and proteomic reprofiling, and they exhibit the greatest signal in a genome-wide screen for genes influencing S. aureus survival in human cells. This effect is likely to be mediated in part via SSR42, a long-noncoding RNA. We show that rsp controls SSR42 expression, is induced by hydrogen peroxide, and is required for normal cytotoxicity and hemolytic activity. Rsp inactivation in laboratory- and bacteremia-derived mutants attenuates toxin production, but up-regulates other immune subversion proteins and reduces lethality during experimental infection. Crucially, inactivation of rsp preserves bacterial dissemination, because it affects neither formation of deep abscesses in mice nor survival in human blood. Thus, we have identified a spontaneously evolving, attenuated-cytotoxicity, nonhemolytic S. aureus phenotype, controlled by a pleiotropic transcriptional regulator/noncoding RNA virulence regulatory system, capable of causing S. aureus bloodstream infections. Such a phenotype could promote deep infection with limited early clinical manifestations, raising concerns that bacterial evolution within the human body may contribute to severe infection.

  12. fliP influences Citrobacter koseri macrophage uptake, cytokine expression and brain abscess formation in the neonatal rat.

    PubMed

    Townsend, Stacy M; Gonzalez-Gomez, Ignacio; Badger, Julie L

    2006-12-01

    Citrobacter koseri causes neonatal meningitis frequently complicated with multiple brain abscesses. During C. koseri central nervous system infection in the neonatal rat model, previous studies have documented many bacteria-filled macrophages within the neonatal rat brain and abscesses. Previous studies have also shown that C. koseri is taken up by, survives phagolysosomal fusion and replicates in macrophages in vitro and in vivo. In this study, in order to elucidate genetic and cellular factors contributing to C. koseri persistence, a combinatory technique of differential fluorescence induction and transposon mutagenesis was employed to isolate C. koseri genes induced while inside macrophages. Several banks of mutants were subjected to a series of enrichments to select for gfp : : transposon fusion into genes that are turned off in vitro but expressed when intracellular within macrophages. Further screening identified several mutants attenuated in their recovery from macrophages compared with the wild-type. A mutation within an Escherichia coli fliP homologue caused significant attenuation in uptake and hypervirulence in vivo, resulting in death within 24 h. Furthermore, analysis of the immunoregulatory interleukin (IL)-10/IL-12 cytokine response during infection suggested that C. koseri fliP expression may alter this response. A better understanding of the bacteria-macrophage interaction at the molecular level and its contribution to brain abscess formation will assist in developing preventative and therapeutic strategies.

  13. Thoracic osteomyelitis and epidural abscess formation due to cat scratch disease: case report.

    PubMed

    Dornbos, David; Morin, Jocelyn; Watson, Joshua R; Pindrik, Jonathan

    2016-12-01

    Osteomyelitis of the spine with associated spinal epidural abscess represents an uncommon entity in the pediatric population, requiring prompt evaluation and diagnosis to prevent neurological compromise. Cat scratch disease, caused by the pathogen Bartonella henselae, encompasses a wide spectrum of clinical presentations; however, an association with osteomyelitis and epidural abscess has been reported in only 4 other instances in the literature. The authors report a rare case of multifocal thoracic osteomyelitis with an epidural abscess in a patient with a biopsy-proven pathogen of cat scratch disease. A 5-year-old girl, who initially presented with vague constitutional symptoms, was diagnosed with cat scratch disease following biopsy of an inguinal lymph node. Despite appropriate antibiotics, she presented several weeks later with recurrent symptoms and back pain. Magnetic resonance imaging revealed 2 foci of osteomyelitis at T-8 and T-11 with an associated anterior epidural abscess from T-9 to T-12. Percutaneous image-guided vertebral biopsy revealed B. henselae by polymerase chain reaction analysis, and she was treated conservatively with doxycycline and rifampin with favorable clinical outcome.

  14. Risk of Liver Abscess Formation in Patients with Prior Biliary Intervention Following Yttrium-90 Radioembolization

    SciTech Connect

    Cholapranee, Aurada; Houten, Diana van; Deitrick, Ginna; Dagli, Mandeep; Sudheendra, Deepak; Mondschein, Jeffrey I.; Soulen, Michael C.

    2015-04-15

    PurposePatients without a competent sphincter of Oddi due to prior surgical or endoscopic therapy are at high risk for liver abscess following chemoembolization despite aggressive antimicrobial prophylaxis. We examined a cohort of such patients undergoing Y-90 resin radioembolization and compared them to a cohort of chemoembolized patients.MethodsReview of our quality-assurance database identified 24 radioembolizations performed in 16 patients with prior biliary intervention. An aggressive prophylactic regimen of oral levofloxacin and metronidazole 2 days pre-procedure continuing for 14 days after, oral neomycin/erythromycin bowel prep the day before, and IV levofloxacin/metronidazole the day of treatment was prescribed. Patients underwent resin microsphere radioembolization dosed according to the BSA method. Patients had clinical, imaging, and laboratory assessment 1 month after each treatment, and then every 3 months. The chemoembolization cohort consisted of 13 patients with prior biliary intervention who had undergone 24 chemoembolization procedures.ResultsNo radioembolization patient developed an abscess. In the cohort of chemoembolized patients who received the same prophylaxis, liver abscess occurred following 3 of 24 (12.5 %) procedures in 3 of 13 (23 %) patients, one fatal.ConclusionsThis preliminary experience suggests that the risk of liver abscess among patients with prior biliary intervention may be lower following radioembolization than chemoembolization, which could potentially expand treatment options in this high-risk population.

  15. Use of gas liquid chromatography as an adjunct to conventional bacteriological methods in the diagnosis of anaerobic cerebral abscess.

    PubMed

    Pit, S; Jamal, F; Cheah, F K; Abbas, M A

    1991-07-01

    Forty cases of cerebral abscesses were studied prospectively to establish the microbial agents implicated in these cases. Chronic otitis media (14 patients, 35%), congenital heart disease (five patients, 12.5%),a and meningitis (five patients, 12.5%) were among the important predisposing factors. Streptococcus (14 patients, 35%) was the most common causative pre-isolated, the predominant species being Streptococcus milleri (11 patients, 27.5%). Other organisms isolated included Proteus mirabilis in six patients (15%) and Staphylococcus aureus in five patients (12.5%). Anaerobes (12 patients, 30%), predominantly Bacteroides sp. (eight patients, 20%), played an important role in these cases, the majority of which were isolated in mixed cultures. Gas-liquid chromatographic analysis of pus detected the presence of anaerobes in another 11 cases of cerebral abscess, in which cultures of anaerobes were negative. Therefore, gas-liquid chromotography is useful as an adjunct to conventional bacteriological methods in providing a rapid and sensitive means of detecting anaerobes in pus obtained especially from patients who had received antibiotic therapy prior to hospitalization.

  16. Star formation sustained by gas accretion

    NASA Astrophysics Data System (ADS)

    Sánchez Almeida, Jorge; Elmegreen, Bruce G.; Muñoz-Tuñón, Casiana; Elmegreen, Debra Meloy

    2014-07-01

    Numerical simulations predict that metal-poor gas accretion from the cosmic web fuels the formation of disk galaxies. This paper discusses how cosmic gas accretion controls star formation, and summarizes the physical properties expected for the cosmic gas accreted by galaxies. The paper also collects observational evidence for gas accretion sustaining star formation. It reviews evidence inferred from neutral and ionized hydrogen, as well as from stars. A number of properties characterizing large samples of star-forming galaxies can be explained by metal-poor gas accretion, in particular, the relationship among stellar mass, metallicity, and star-formation rate (the so-called fundamental metallicity relationship). They are put forward and analyzed. Theory predicts gas accretion to be particularly important at high redshift, so indications based on distant objects are reviewed, including the global star-formation history of the universe, and the gas around galaxies as inferred from absorption features in the spectra of background sources.

  17. Fulminating gas-forming psoas muscle abscess due to Klebsiella pneumoniae following a deep neck infection.

    PubMed

    Jang, T N; Juang, G D; Fung, C P

    1997-02-01

    Psoas muscle abscess due to Klebsiella pneumoniae infection is rare. We report a 55-year-old diabetic man who presented with progressive back pain of 1 month's duration. The patient had undergone surgical drainage for a deep neck infection with K. pneumoniae 43 days previously. On the present admission, physical examination revealed tenderness over the anterior upper aspect of both thighs, and computed tomography showed pneumoretroperitoneum dissecting the bilateral iliopsoas muscles. Parenteral administration of antibiotics was started immediately. Due to the patient's poor health status, we opted for repeated computed tomographic and sonographic-guided percutaneous drainage rather than surgical drainage. Blood and pus cultures revealed only K. pneumoniae. The patient recovered without significant sequelae. This report stresses the risk of metastatic infections caused by K. pneumoniae, especially in diabetic patients. Our experience suggests that repeated percutaneous drainage is feasible in cases of severe iliopsoas abscess, especially when risks associated with surgery are high.

  18. The pathology of experimentally induced cecal amebiasis in gerbils (Meriones unguiculatus). Liver changes and amebic liver abscess formation.

    PubMed Central

    Chadee, K.; Meerovitch, E.

    1985-01-01

    The pathogenesis of experimentally induced cecal amebiasis in gerbils (Meriones unguiculatus) was studied from 5 to 60 days after inoculation. Ulcerative lesions were noted 10 to 60 days after inoculation. The sequential development of lesions was asynchronous and progressed from destruction of the interglandular epithelium and of glandular crypt elements to loss of mucosa and formation of granulomatous lesions in the submucosa involving the muscularis mucosae. Pathologic changes in the liver correlated with the formation of ulcerative cecal lesions. Subacute hepatic changes showed lymphocytic portal infiltrate, Kupffer cell hyperplasia, multinucleated giant cells, granuloma formation, and sinusoidal mononuclear and granulocytic infiltrates. Metastatic amebic liver abscesses occurred as early as 10 days after inoculation, and small abscesses were found in the portal areas of the right liver lobe. The sequential development and pathologic manifestation of the infection and the usefulness of the gerbil for the study of human intestinal amebiasis are discussed. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15 Figure 16 Figure 17 Figure 18 PMID:4014436

  19. Epidural abscess

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/001416.htm Epidural abscess To use the sharing features on this page, please enable JavaScript. An epidural abscess is a collection of pus (infected material) between ...

  20. Pancreatic abscess

    MedlinePlus

    ... high. Possible Complications Complications may include: Multiple abscesses Sepsis When to Contact a Medical Professional Call your ... 2016:chap 144. Read More Abscess Pancreatic pseudocyst Sepsis Review Date 10/27/2015 Updated by: Subodh ...

  1. Natural gas: Formation of hydrates -- Transportation

    SciTech Connect

    Bhaskara Rao, B.K.

    1998-07-01

    The significant growth of Natural gas based industries in India and elsewhere obviously forced the industry to hunt for new fields and sources. This has naturally led to the phenomenal growth of gas networks. The transportation of gas over thousands of kilometers through caprious ambient conditions requires a great effort. Many difficulties such as condensation of light liquids (NGLS), choking of lines due to formation of hydrates, improper distribution of gas into branches are experienced during pipe line transportation of Natural gas. The thermodynamic conditions suitable for formation of solid hydrates have been derived depending upon the constituents of natural gas. Further effects of branching in pipe line transportation have been discussed.

  2. A Late-onset Psoas Abscess Formation Associated with Previous Appendectomy: A Case Report.

    PubMed

    Moslemi, Sam; Tahamtan, Maryam; Hosseini, Seyed Vahid

    2014-01-01

    Psoas abscesses could originate from an adjacent source of infection in the abdominopelvic cavity known as a secondary complication of acute appendicitis. However, it is considered as a very rare event when occurring late after the presentation of appendicitis. Whether it is the source or complication of acute appendicitis following appendectomy remains unclear. A 25-year-old man was admitted to our center with fever and abdominal pain. His past medical history was unremarkable except for having an acute appendicitis and complicated appendectomy 4 years before presenting illness. On admission, the patient was febrile with right lower quadrant abdominal tenderness and moderate leukocytosis. The Abdominopelvic CT- scan revealed a large right psoas muscle than the opposite site, that contained a hypodense mass measuring 6 cm in diameter with extension into right iliacus and internal oblique muscles..The patient underwent subsequent percutaneous abscess drainage under image guide and concurrent broad-spectrum antibiotic therapy.

  3. Gas formation. Formation temperatures of thermogenic and biogenic methane.

    PubMed

    Stolper, D A; Lawson, M; Davis, C L; Ferreira, A A; Santos Neto, E V; Ellis, G S; Lewan, M D; Martini, A M; Tang, Y; Schoell, M; Sessions, A L; Eiler, J M

    2014-06-27

    Methane is an important greenhouse gas and energy resource generated dominantly by methanogens at low temperatures and through the breakdown of organic molecules at high temperatures. However, methane-formation temperatures in nature are often poorly constrained. We measured formation temperatures of thermogenic and biogenic methane using a "clumped isotope" technique. Thermogenic gases yield formation temperatures between 157° and 221°C, within the nominal gas window, and biogenic gases yield formation temperatures consistent with their comparatively lower-temperature formational environments (<50°C). In systems where gases have migrated and other proxies for gas-generation temperature yield ambiguous results, methane clumped-isotope temperatures distinguish among and allow for independent tests of possible gas-formation models.

  4. Study of Formation Mechanisms of Gas Hydrate

    NASA Astrophysics Data System (ADS)

    Yang, Jia-Sheng; Wu, Cheng-Yueh; Hsieh, Bieng-Zih

    2015-04-01

    Gas hydrates, which had been found in subsurface geological environments of deep-sea sediments and permafrost regions, are solid crystalline compounds of gas molecules and water. The estimated energy resources of hydrates are at least twice of that of the conventional fossil fuel in the world. Gas hydrates have a great opportunity to become a dominating future energy. In the past years, many laboratory experiments had been conducted to study chemical and thermodynamic characteristics of gas hydrates in order to investigate the formation and dissociation mechanisms of hydrates. However, it is difficult to observe the formation and dissociation of hydrates in a porous media from a physical experiment directly. The purpose of this study was to model the dynamic formation mechanisms of gas hydrate in porous media by reservoir simulation. Two models were designed for this study: 1) a closed-system static model with separated gas and water zones; this model was a hydrate equilibrium model to investigate the behavior of the formation of hydrates near the initial gas-water contact; and 2) an open-system dynamic model with a continuous bottom-up gas flow; this model simulated the behavior of gas migration and studied the formation of hydrates from flowed gas and static formation water in porous media. A phase behavior module was developed in this study for reservoir simulator to model the pressure-volume-temperature (PVT) behavior of hydrates. The thermodynamic equilibriums and chemical reactions were coupled with the phase behavior module to have functions modelling the formation and dissociation of hydrates from/to water and gas. The simulation models used in this study were validated from the code-comparison project proposed by the NETL. According to the modelling results of the closed-system static model, we found that predominated location for the formation of hydrates was below the gas-water contact (or at the top of water zone). The maximum hydrate saturation

  5. An emboligenic pulmonary abscess leading to ischemic stroke and secondary brain abscess.

    PubMed

    Albrecht, Philipp; Stettner, Mark; Husseini, Leila; Macht, Stephan; Jander, Sebastian; Mackenzie, Colin; Oesterlee, Ulrike; Slotty, Philipp; Methner, Axel; Hartung, Hans-Peter; Aktas, Orhan

    2012-11-05

    Ischemic stroke by septic embolism occurs primarily in the context of infective endocarditis or in patients with a right-to-left shunt and formation of a secondary cerebral abscess is a rare event. Erosion of pulmonary veins by a pulmonary abscess can lead to transcardiac septic embolism but to our knowledge no case of septic embolic ischemic stroke from a pulmonary abscess with secondary transformation into a brain abscess has been reported to date. We report the case of a patient with a pulmonary abscess causing a septic embolic cerebral infarction which then transformed into a cerebral abscess. After antibiotic therapy and drainage of the abscess the patient could be rehabilitated and presented an impressive improvement of symptoms. Septic embolism should be considered as cause of ischemic stroke in patients with pulmonary abscess and can be followed by formation of a secondary cerebral abscess. Early antibiotic treatment and repeated cranial CT-scans for detection of a secondary abscess should be performed.

  6. Gas Accretion and Star Formation Rates

    NASA Astrophysics Data System (ADS)

    Sánchez Almeida, Jorge

    Cosmological numerical simulations of galaxy evolution show that accretion of metal-poor gas from the cosmic web drives the star formation in galaxy disks. Unfortunately, the observational support for this theoretical prediction is still indirect, and modeling and analysis are required to identify hints as actual signs of star formation feeding from metal-poor gas accretion. Thus, a meticulous interpretation of the observations is crucial, and this observational review begins with a simple theoretical description of the physical process and the key ingredients it involves, including the properties of the accreted gas and of the star formation that it induces. A number of observations pointing out the connection between metal-poor gas accretion and star formation are analyzed, specifically, the short gas-consumption time-scale compared to the age of the stellar populations, the fundamental metallicity relationship, the relationship between disk morphology and gas metallicity, the existence of metallicity drops in starbursts of star-forming galaxies, the so-called G dwarf problem, the existence of a minimum metallicity for the star-forming gas in the local universe, the origin of the α-enhanced gas forming stars in the local universe, the metallicity of the quiescent BCDs, and the direct measurements of gas accretion onto galaxies. A final section discusses intrinsic difficulties to obtain direct observational evidence, and points out alternative observational pathways to further consolidate the current ideas.

  7. Pancreatic abscesses.

    PubMed

    Shi, E C; Yeo, B W; Ham, J M

    1984-09-01

    This paper presents the clinical features and problems in the management of 34 patients with pancreatic abscesses. In the majority of patients the abscesses developed following an attack of pancreatitis due to alcohol or gallstones. The abscesses were usually multilocular, and often had spread widely in the retroperitoneal space. Invasion into surrounding viscera or the peritoneal cavity occurred in 12 instances, and eight patients developed major bleeding into the abscess cavity. Obstructive complications (affecting bowel, common bile duct and large veins) occurred in eight patients. Twelve of the 34 patients (35 per cent) died, most deaths being due to failure to control sepsis (seven patients) or to massive bleeding from the abscess cavity (three patients). The mortality of this condition is likely to remain high, but may be reduced by better drainage techniques at the initial exploration. The importance of the infra-mesocolic approach for drainage is emphasized.

  8. Gas-Phase Infrared; JCAMP Format

    National Institute of Standards and Technology Data Gateway

    SRD 35 NIST/EPA Gas-Phase Infrared; JCAMP Format (PC database for purchase)   This data collection contains 5,228 infrared spectra in the JCAMP-DX (Joint Committee for Atomic and Molecular Physical Data "Data Exchange") format.

  9. Intracranial abscess in Ectopia Cordis.

    PubMed

    Merola, Joseph; Tipper, Geoffrey Adrian; Hussain, Zakier; Balakrishnan, Venkataraman; Gan, Peter

    2014-08-25

    We present a case of intracranial abscess in a young female with Ectopia Cordis, an exceptionally rare cardiac condition. The neurosurgical implication is the predisposition to intracranial abscess formation. A heightened awareness of this association will aid diagnosis in similar clinical scenarios.

  10. Visualization of Abscess Formation in a Murine Thigh Infection Model of Staphylococcus aureus by 19F-Magnetic Resonance Imaging (MRI)

    PubMed Central

    Kircher, Stefan; Basse-Lüsebrink, Thomas; Haddad, Daniel; Ohlsen, Knut; Jakob, Peter

    2011-01-01

    Background During the last years, 19F-MRI and perfluorocarbon nanoemulsion (PFC) emerged as a powerful contrast agent based MRI methodology to track cells and to visualize inflammation. We applied this new modality to visualize deep tissue abscesses during acute and chronic phase of inflammation caused by Staphylococcus aureus infection. Methodology and Principal Findings In this study, a murine thigh infection model was used to induce abscess formation and PFC or CLIO (cross linked ironoxides) was administered during acute or chronic phase of inflammation. 24 h after inoculation, the contrast agent accumulation was imaged at the site of infection by MRI. Measurements revealed a strong accumulation of PFC at the abscess rim at acute and chronic phase of infection. The pattern was similar to CLIO accumulation at chronic phase and formed a hollow sphere around the edema area. Histology revealed strong influx of neutrophils at the site of infection and to a smaller extend macrophages during acute phase and strong influx of macrophages at chronic phase of inflammation. Conclusion and Significance We introduce 19F-MRI in combination with PFC nanoemulsions as a new platform to visualize abscess formation in a murine thigh infection model of S. aureus. The possibility to track immune cells in vivo by this modality offers new opportunities to investigate host immune response, the efficacy of antibacterial therapies and the influence of virulence factors for pathogenesis. PMID:21455319

  11. Primary psoas muscle abscess in pregnancy.

    PubMed

    Swanson, Amy; Lau, Kenneth K; Korman, Tony M; Kornman, Tony; Wallace, Euan M; Polyakov, Alex

    2008-12-01

    Primary iliacus-psoas muscle abscess formation is very uncommon during pregnancy. We present a case of a primary iliacus-psoas muscle abscess in pregnancy causing back pain with delayed diagnosis and treatment. Understanding the clinical presentation of iliacus-psoas muscle abscess helps with considering it in the differential diagnosis of back pain during pregnancy.

  12. Presacral abscess as a rare complication of sacral nerve stimulator implantation.

    PubMed

    Gumber, A; Ayyar, S; Varia, H; Pettit, S

    2017-03-01

    A 50-year-old man with intractable anal pain attributed to proctalgia fugax underwent insertion of a sacral nerve stimulator via the right S3 vertebral foramen for pain control with good symptomatic relief. Thirteen months later, he presented with signs of sepsis. Computed tomography (CT) and magnetic resonance imaging (MRI) showed a large presacral abscess. MRI demonstrated increased enhancement along the pathway of the stimulator electrode, indicating that the abscess was caused by infection introduced at the time of sacral nerve stimulator placement. The patient was treated with broad spectrum antibiotics, and the sacral nerve stimulator and electrode were removed. Attempts were made to drain the abscess transrectally using minimally invasive techniques but these were unsuccessful and CT guided transperineal drainage was then performed. Despite this, the presacral abscess progressed, developing enlarging gas locules and extending to the pelvic brim to involve the aortic bifurcation, causing hydronephrosis and radiological signs of impending sacral osteomyelitis. MRI showed communication between the rectum and abscess resulting from transrectal drainage. In view of the progressive presacral sepsis, a laparotomy was performed with drainage of the abscess, closure of the upper rectum and formation of a defunctioning end sigmoid colostomy. Following this, the presacral infection resolved. Presacral abscess formation secondary to an infected sacral nerve stimulator electrode has not been reported previously. Our experience suggests that in a similar situation, the optimal management is to perform laparotomy with drainage of the presacral abscess together with simultaneous removal of the sacral nerve stimulator and electrode.

  13. Brain abscess.

    PubMed

    Slazinski, Tess

    2013-09-01

    A brain abscess is defined as a localized collection of pus within the parenchyma of the brain or meninges. Brain abscesses are a complication of ear, sinus, and/or dental infections. Although they may occur in many brain locations, the most common sites are frontal and temporal lobes. Modern neuroimaging and laboratory analysis have led to prompt diagnosis and have decreased the mortality rates from brain abscess. Critical care nurses have a vital role in performing accurate neurologic assessments, timely administration of antibiotics, and management of fever. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Gas hydrate formation in reversed micelles

    SciTech Connect

    Nguyen, H.; Rao, A.M.; Phillips, J.B.; John, V.T.; Reed, W.F.

    1991-12-31

    We describe a technique to modify protein solubility and optimize enzyme activity in reversed micellar solutions. The technique is based on the ability of hydrates of natural gas to form in the microaqueous phase. Clathrate hydrates are crystalline inclusions of water and gas, and their formation in bulk water has traditionally been studied with relevance to natural gas recovery. We have found that hydrates can form in the environment of the microaqueous pools of reversed micelles, and that their extent of formation can be well controlled through the thermodynamic variables of temperature and pressure. Additionally, formation of hydrates affects the size and aggregation number of the micelles, and thus influences the solubility and conformation of encapsulated proteins. We demonstrate how the concept can be used in two applications: (1) protein extraction into reversed micelles and subsequent recovery, and (2) optimization of enzyme activity in reversed micelles.

  15. Anorectal abscess

    MedlinePlus

    ... an anal fissure Sexually transmitted infection (STD) Trauma Deep rectal abscesses may be caused by intestinal disorders ... drains the pus. If the pus collection is deep, you may need to stay in the hospital ...

  16. Subareolar abscess

    MedlinePlus

    Your health care provider will perform a breast exam. Sometimes an ultrasound or other imaging test of the breast is recommended. A blood count and a culture of the abscess, if drained, may be ordered.

  17. Splenic abscesses.

    PubMed

    Al-Hajjar, Nadim; Graur, Florin; Hassan, Aboul B; Molnár, Geza

    2002-03-01

    Splenic abscesses are rare entities (autopsy incidence between 0.14-0.7%). The most frequent etiology is the septic emboli seeding from bacterial endocarditis (about 20% of cases) or other septic foci (typhoid fever, malaria, urinary tract infections, osteomielitis, otitis). The treatment of splenic abscesses was until recently splenectomy with antibiotherapy. The actual trends are more conservative (mini invasive or non-invasive) because the immunologic role of the spleen has been better understood over the last year

  18. Catheter colonization and abscess formation due to Staphylococcus epidermidis with normal and small-colony-variant phenotype is mouse strain dependent.

    PubMed

    Sander, Gunnar; Börner, Tina; Kriegeskorte, André; von Eiff, Christof; Becker, Karsten; Mahabir, Esther

    2012-01-01

    Coagulase-negative staphylococci (CoNS) form a thick, multilayered biofilm on foreign bodies and are a major cause of nosocomial implant-associated infections. Although foreign body infection models are well-established, limited in vivo data are available for CoNS with small-colony-variant (SCV) phenotype described as causative agents in implant-associated infections. Therefore, we investigated the impact of the Staphylococcus epidermidis phenotype on colonization of implanted PVC catheters and abscess formation in three different mouse strains. Following introduction of a catheter subcutaneously in each flank of 8- to 12-week-old inbred C57BL/6JCrl (B6J), outbred Crl:CD1(ICR) (CD-1), and inbred BALB/cAnNCrl (BALB/c) male mice, doses of S. epidermidis O-47 wild type, its hemB mutant with stable SCV phenotype, or its complemented mutant at concentrations of 10(6) to 10(9) colony forming units (CFUs) were gently spread onto each catheter. On day 7, mice were sacrificed and the size of the abscesses as well as bacterial colonization was determined. A total of 11,500 CFUs of the complemented mutant adhered to the catheter in BALB/c followed by 9,960 CFUs and 9,900 CFUs from S. epidermidis wild type in BALB/c and CD-1, respectively. SCV colonization was highest in CD-1 with 9,500 CFUs, whereas SCVs were not detected in B6J. The minimum dose that led to colonization or abscess formation in all mouse strains was 10(7) or 10(8) CFUs of the normal phenotype, respectively. A minimum dose of 10(8) or 10(9) CFU of the hemB mutant with stable SCV phenotype led to colonization only or abscess formation, respectively. The largest abscesses were detected in BALB/c inoculated with wild type bacteria or SCV (64 mm(2) vs. 28 mm(2)). Our results indicate that colonization and abscess formation by different phenotypes of S. epidermidis in a foreign body infection model is most effective in inbred BALB/c followed by outbred CD-1 and inbred B6J mice.

  19. Ice-gas interactions during planet formation

    NASA Astrophysics Data System (ADS)

    Oberg, Karin I.

    2015-08-01

    The interplay between ice and gas in protoplanetary disks is believed to have played a critical role in the formation of the Solar System, and should be affecting the ongoing formation of exoplanets in the disks (Solar Nebula analogs) observed around young stars. “Snowlines”, i.e. the midplane condensation fronts of major volatiles such as water and CO in protoplanetary disks, should enhance particle growth and thus planet formation efficiencies. More importantly for this session, snowline locations affect the relative ice and gas molecular and elemental composition throughout the disk, which in its turn affects elemental composition of planetesimals as well as their water and organic content.Snowline locations are set by a combination of chemistry, ice sublimation energy barriers, and protoplanetary disk temperature and density structures. Together these properties regulate the abundances of the most common volatiles, in which temperature regimes these volatiles are predominantly present as ice, and where in the disk such temperatures are realized. Ice chemistry also regulates the organic trace composition of icy bodies, i.e. the abundances of cyanides and other prebiotically interesting molecules. The past couple of years have given us the first observations of snowlines in protoplanetary disks. There is also evidence of an active ice chemistry in disks and feedback of this chemistry into the gas-phase through thermal and non-thermal desorption. I will review the protoplanetary disk, protostellar and Solar System observations and models that can help us constrain what the most common volatiles are during planet formation, how the volatiles are distributed between ice and gas in the disk at different distances from the star (Sun), and how ice-gas interactions may enable us to trace the underlying ice reservoir during planet formation using gas-phase observations of protoplanetary disks.

  20. Spinal cord abscess

    MedlinePlus

    ... abscess usually occurs as a complication of an epidural abscess . Pus forms as a collection of: Destroyed tissue ... bone ( osteomyelitis ). The bone infection may cause an epidural abscess to form. This abscess gets larger and presses ...

  1. Core Accretion - Gas Capture Model for Gas Giant Planet Formation

    NASA Astrophysics Data System (ADS)

    Hubickyj, O.; Bodenheimer, P.; Lissauer, J. J.

    2005-12-01

    The core accretion - gas capture model is generally accepted as the standard formation model for gas giant planets. This model proposes that a solid core grows via the accretion of planetesimals and then captures a massive envelope from the solar nebula gas. Simulations based on this model (Pollack et al. 1996, Bodenheimer et al. 2000) have been successful in explaining many features of giant planets. We have computed simulations (Hubickyj et al. 2005) of the growth of Jupiter using various values for the opacity produced by grains in the protoplanet's atmosphere and for the initial planetesimal surface density in the protoplanetary disk. We also explore the implications of halting the solid accretion at selected core mass values during the protoplanet's growth. Halting planetesimal accretion at low core mass simulates the presence of a competing embryo, and decreasing the atmospheric opacity due to grains emulates the settling and coagulation of grains within the protoplanet's atmosphere. We examine the effects of adjusting these parameters to determine whether or not gas runaway can occur for small mass cores on a reasonable timescale. Our results demonstrate that reducing grain opacities results in formation times less than half of those for models computed with full interstellar grain opacity values. The reduction of opacity due to grains in the upper portion of the envelope with T ≤ 500 K has the largest effect on the lowering of the formation time. If the accretion of planetesimals is not cut off prior to the accretion of gas, then decreasing the surface density of planetesimals lowers the final core mass of the protoplanet, but increases the formation timescale considerably. Finally, a core mass cutoff results in a reduction of the time needed for a protoplanet to evolve to the stage of runaway gas accretion, provided the cutoff mass is sufficiently large. The overall results indicate that, with reasonable parameters, it is possible that Jupiter formed at

  2. Haloarchaea and the Formation of Gas Vesicles

    PubMed Central

    Pfeifer, Felicitas

    2015-01-01

    Halophilic Archaea (Haloarchaea) thrive in salterns containing sodium chloride concentrations up to saturation. Many Haloarchaea possess genes encoding gas vesicles, but only a few species, such as Halobacterium salinarum and Haloferax mediterranei, produce these gas-filled, proteinaceous nanocompartments. Gas vesicles increase the buoyancy of cells and enable them to migrate vertically in the water body to regions with optimal conditions. Their synthesis depends on environmental factors, such as light, oxygen supply, temperature and salt concentration. Fourteen gas vesicle protein (gvp) genes are involved in their formation, and regulation of gvp gene expression occurs at the level of transcription, including the two regulatory proteins, GvpD and GvpE, but also at the level of translation. The gas vesicle wall is solely formed of proteins with the two major components, GvpA and GvpC, and seven additional accessory proteins are also involved. Except for GvpI and GvpH, all of these are required to form the gas permeable wall. The applications of gas vesicles include their use as an antigen presenter for viral or pathogen proteins, but also as a stable ultrasonic reporter for biomedical purposes. PMID:25648404

  3. 18 CFR 270.304 - Tight formation gas.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Tight formation gas... Requirements for Filings With Jurisdictional Agencies § 270.304 Tight formation gas. A person seeking a determination that natural gas is tight formation gas must file with the jurisdictional agency an application...

  4. Controls on Gas Hydrate Formation and Dissociation

    SciTech Connect

    Miriam Kastner; Ian MacDonald

    2006-03-03

    The main objectives of the project were to monitor, characterize, and quantify in situ the rates of formation and dissociation of methane hydrates at and near the seafloor in the northern Gulf of Mexico, with a focus on the Bush Hill seafloor hydrate mound; to record the linkages between physical and chemical parameters of the deposits over the course of one year, by emphasizing the response of the hydrate mound to temperature and chemical perturbations; and to document the seafloor and water column environmental impacts of hydrate formation and dissociation. For these, monitoring the dynamics of gas hydrate formation and dissociation was required. The objectives were achieved by an integrated field and laboratory scientific study, particularly by monitoring in situ formation and dissociation of the outcropping gas hydrate mound and of the associated gas-rich sediments. In addition to monitoring with the MOSQUITOs, fluid flow rates and temperature, continuously sampling in situ pore fluids for the chemistry, and imaging the hydrate mound, pore fluids from cores, peepers and gas hydrate samples from the mound were as well sampled and analyzed for chemical and isotopic compositions. In order to determine the impact of gas hydrate dissociation and/or methane venting across the seafloor on the ocean and atmosphere, the overlying seawater was sampled and thoroughly analyzed chemically and for methane C isotope ratios. At Bush hill the pore fluid chemistry varies significantly over short distances as well as within some of the specific sites monitored for 440 days, and gas venting is primarily focused. The pore fluid chemistry in the tub-warm and mussel shell fields clearly documented active gas hydrate and authigenic carbonate formation during the monitoring period. The advecting fluid is depleted in sulfate, Ca Mg, and Sr and is rich in methane; at the main vent sites the fluid is methane supersaturated, thus bubble plumes form. The subsurface hydrology exhibits both

  5. [Splenic abscess].

    PubMed

    Troncoso, P; Geni, R; Llanos, O

    1989-06-01

    Splenic abscess is an uncommon condition associated with a high mortality. In most cases an hematogenous focus can be identified. Early diagnosis is essential for recovery. CT scan and ultrasound tomography are the best diagnostic tools. The latter was used to establish the diagnosis in 2 patients who were successfully treated by surgery.

  6. Brain abscess.

    PubMed

    Sáez-Llorens, Xavier; Nieto-Guevara, Javier

    2013-01-01

    Brain abscess is a serious and life-threatening disease among children despite advances in diagnosis and management. Changes in the epidemiology of predisposing conditions for brain abscess are associated with changes in the patient population and causative organisms. Though still a potentially fatal infection, there have been recent improvements in diagnosis, treatment, and outcome. Although mortality appears to be decreasing, a significant percentage of children continue to have residual neurological deficits, including epilepsy, permanent motor or sensory dysfunction, visual field defects, and personality change. Some children also require placement of a ventriculoperitoneal shunt. The most common origin of microbial infection in children remains direct or indirect cranial infection arising from the middle ear, paranasal sinuses, or teeth. No prospective clinical trials have compared the various surgical and medical treatment strategies available to guide the management of cerebral abscesses in children. Most surgical and medical treatment guidelines are based on populations consisting primarily of adult patients. The use of corticosteroids for treatment of brain abscess is controversial. Anticonvulsants are recommended in children who have developed seizures potentially to prevent further episodes. Duration of anticonvulsant therapy should be individualized and guided by electroencephalographic (EEG) study in the follow-up phase of disease. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Pathogenesis of Staphylococcus aureus abscesses.

    PubMed

    Kobayashi, Scott D; Malachowa, Natalia; DeLeo, Frank R

    2015-06-01

    Staphylococcus aureus causes many types of human infections and syndromes-most notably skin and soft tissue infections. Abscesses are a frequent manifestation of S. aureus skin and soft tissue infections and are formed, in part, to contain the nidus of infection. Polymorphonuclear leukocytes (neutrophils) are the primary cellular host defense against S. aureus infections and a major component of S. aureus abscesses. These host cells contain and produce many antimicrobial agents that are effective at killing bacteria, but can also cause non-specific damage to host tissues and contribute to the formation of abscesses. By comparison, S. aureus produces several molecules that also contribute to the formation of abscesses. Such molecules include those that recruit neutrophils, cause host cell lysis, and are involved in the formation of the fibrin capsule surrounding the abscess. Herein, we review our current knowledge of the mechanisms and processes underlying the formation of S. aureus abscesses, including the involvement of polymorphonuclear leukocytes, and provide a brief overview of therapeutic approaches.

  8. Ice Formation in Gas-Diffusion Layers

    SciTech Connect

    Dursch, Thomas; Radke, Clayton J.; Weber, Adam Z.

    2010-07-10

    Under sub-freezing conditions, ice forms in the gas-diffusion layer (GDL) of a proton exchange membrane fuel cell (PEMFC) drastically reducing cell performance. Although a number of strategies exist to prevent ice formation, there is little fundamental understanding of the mechanisms of freezing within PEMFC components. Differential scanning calorimetry (DSC) is used to elucidate the effects of hydrophobicity (Teflon® loading) and water saturation on the rate of ice formation within three commercial GDLs. We find that as the Teflon® loading increases, the crystallization temperature decreases due to a change in internal ice/substrate contact angle, as well as the attainable level of water saturation. Classical nucleation theory predicts the correct trend in freezing temperature with Teflon® loading.

  9. Pituitary abscess.

    PubMed

    Al Salman, Jameela Mohammed; Al Agha, Rawan Al Muataz Billa; Helmy, Mohamed

    2017-06-08

    Pituitary abscess is an uncommon pituitary lesion. Its clinical diagnosis can be difficult to distinguish from other pituitary lesions. This pathology is characterised by vague symptoms of headaches, generalised tiredness and hypopituitarism manifestations. A history of recent meningitis, paranasal sinusitis or head surgery can be a suggestive of the source of infection.A 20-year-old man was admitted to neurosurgery department with complain of headache, fatigue, polyuria, polydipsia, blurred vision and sexual dysfunction. MRI of the head revealed a suprasellar mass that was centrally hyperintense lesion on T2-weighted images with peripheral hypointensity and isointense centrally on T1 images with peripheral hyperintensity images. Treatment of this lesion pituitary abscess was surgical drainage of the pituitary area through a trans-sphenoidal approach and broad spectrum antibiotic therapy with ceftriaxone, metronidazole and vancomycin for 6 weeks. The patient continues to have pituitary insufficiency and treated with oral hydrocortisone.Although pituitary abscess is a rare condition, it should always be kept in mind when evaluating a patient with hypopituitarism. After the diagnosis, the surgery and antibiotics should be commenced rapidly. The outcome is usually good with proper treatment. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  10. Pyogenic liver abscess

    MedlinePlus

    Liver abscess; Bacterial liver abscess ... There are many possible causes of liver abscesses, including: Abdominal infection, such as appendicitis , diverticulitis , or a perforated bowel Infection in the blood Infection of the bile draining tubes ...

  11. Amebic liver abscess

    MedlinePlus

    Hepatic amebiasis; Extraintestinal amebiasis; Abscess - amebic liver ... Amebic liver abscess is caused by Entamoeba histolytica. This parasite causes amebiasis , an intestinal infection that is also called ...

  12. Late-onset posttraumatic septal hematoma and abscess formation in a six-year-old Tamil girl--case report and literature review.

    PubMed

    Dubach, Patrick; Aebi, Christoph; Caversaccio, Marco

    2008-12-01

    Nasal septal hematoma with abscess (NSHA) is an uncommon complication of trauma and studies on children are especially rare. We discuss the case of a 6-year-old girl, who was initially evaluated independently by three doctors for minor nasal trauma but had to be re-hospitalized 6 days later with NSHA. Although septal hematoma had initially been excluded (5, 7 and 24 hours after trauma), a secondary accumulation of blood seems to have occured. Delayed hematoma formation has been described in the orbit as a result of possible venous injuries after endoscopic sinus surgery. However, such an observation is new for septal hematoma in children. Thus, we recommend re-evaluation for septal hematoma 48h to 72h after paediatric nasal trauma. Such a scheduled re-examination offers a chance to treat delayed subperichondral hematoma on time before almost inevitable superinfection leads to abscess formation and destruction of the nasal infrastructure. We suggest that parents should be vigilant for delayed nasal obstruction as possible herald of hematoma accumulation within the first week.

  13. 18 CFR 270.304 - Tight formation gas.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., where such gas could not have been produced from any completion location in existence in the well bore... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Tight formation gas... Requirements for Filings With Jurisdictional Agencies § 270.304 Tight formation gas. A person seeking...

  14. 18 CFR 270.304 - Tight formation gas.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., where such gas could not have been produced from any completion location in existence in the well bore... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Tight formation gas... Requirements for Filings With Jurisdictional Agencies § 270.304 Tight formation gas. A person seeking...

  15. Retropharyngeal abscess.

    PubMed Central

    Coulthard, M; Isaacs, D

    1991-01-01

    Of 31 children with retropharyngeal abscess treated at this hospital between 1954 and 1990, 17 (55%) were 12 months old or less and 10 (32%) less than 6 months. Three of these 10 children were neonates, only one of whom had a predisposing congenital lesion. Fourteen children (45%) had a preceding upper respiratory illness and four (13%) had a prior history of pharyngeal trauma or ingestion of a foreign body. In children less than 1 year old the clinical presentation was usually classical with fever, neck swelling, stridor, and pharyngeal swelling. Significantly fewer children over 1 year had neck swelling and no child over 3 years old had stridor. A lateral radiograph of the neck, when performed, had a sensitivity of 88% in diagnosis. Bacteria isolated included pure growths of Staphylococcus aureus (25%), klebsiella species (13%), group A streptococcus (8%), and a mixture of Gram negative and anaerobic organisms (38%). There were two deaths. In six cases (24%) the abscess recurred necessitating further surgical drainage. Images Figure 2 PMID:1953008

  16. A lingual abscess caused by Streptococcus intermedius.

    PubMed

    Harrington, Amanda T; Hsia, Jennifer C; Mendez, Eduardo; Clarridge, Jill E

    2012-04-01

    Lingual abscesses are rare. We describe a case in a healthy female with no recent history of trauma. The organism recovered by culture of drainage material collected prior to antibiotic treatment was Streptococcus intermedius, an organism recognized as flora of the oropharynx and associated with abscess formation. The isolate was resistant to clindamycin, which was the antibiotic therapy that the patient received.

  17. An emboligenic pulmonary abscess leading to ischemic stroke and secondary brain abscess

    PubMed Central

    2012-01-01

    Background Ischemic stroke by septic embolism occurs primarily in the context of infective endocarditis or in patients with a right-to-left shunt and formation of a secondary cerebral abscess is a rare event. Erosion of pulmonary veins by a pulmonary abscess can lead to transcardiac septic embolism but to our knowledge no case of septic embolic ischemic stroke from a pulmonary abscess with secondary transformation into a brain abscess has been reported to date. Case presentation We report the case of a patient with a pulmonary abscess causing a septic embolic cerebral infarction which then transformed into a cerebral abscess. After antibiotic therapy and drainage of the abscess the patient could be rehabilitated and presented an impressive improvement of symptoms. Conclusion Septic embolism should be considered as cause of ischemic stroke in patients with pulmonary abscess and can be followed by formation of a secondary cerebral abscess. Early antibiotic treatment and repeated cranial CT-scans for detection of a secondary abscess should be performed. PMID:23121862

  18. CT of pituitary abscess

    SciTech Connect

    Fong, T.C.; Johns, R.D.; Long, M.; Myles, S.T.

    1985-06-01

    Pituitary abscess is a rare condition, with only 50 cases reported in the literature. Of those, 29 cases were well documented for analysis. Preoperative diagnosis of pituitary abscess is difficult. The computed tomographic (CT) appearance of pituitary abscess was first described in 1983; the abscess was depicted by axial images with coronal reconstruction. The authors recently encountered a case of pituitary abscess documented by direct coronal CT of the sella turcica.

  19. Gas dynamic simulations of galaxy formation

    NASA Technical Reports Server (NTRS)

    Evrard, August E.

    1993-01-01

    Results are presented from a simulation modeling the formation of a group of galaxies in a 'standard' cold, dark matter universe with delta = 1, h sub 0 = 50 km/(s(Mpc)), baryon fraction omega sub b = 0.1 and spectrum normalization sigma sub 8 = 0.6 (bias parameter b = 1.7). Initial conditions are generated within a periodic box with comoving length 16 Mpc in a manner constrained to produce a small cluster of total mass approximately 10 exp 14 solar mass. Two sets of 643 particles are used to model the dark matter and baryon fluids. Each gas particle represents 1.08 x 10 exp -8 solar mass, implying an L* galaxy is resolved by approximately 1000 particles. The system is evolved self-consistently in three dimensions using the combined N-body/hydrodynamic scheme P3MSPH up to a final redshift z = 1. Evolving to the present is prohibited by the fact that the mean density in the simulated volume is above critical and the entire volume would be going nonlinear beyond this point, We are currently analyzing another run with somewhat poorer mass resolution which was evolved to the present.

  20. Creating and maintaining a gas cap in tar sands formations

    DOEpatents

    Vinegar, Harold J.; Karanikas, John Michael; Dinkoruk, Deniz Sumnu; Wellington, Scott Lee

    2010-03-16

    Methods for treating a tar sands formation are disclosed herein. Methods for treating a tar sands formation may include providing heat to at least part of a hydrocarbon layer in the formation from one or more heaters located in the formation. Pressure may be allowed to increase in an upper portion of the formation to provide a gas cap in the upper portion. At least some hydrocarbons are produced from a lower portion of the formation.

  1. Overexpression of Differentially Expressed Genes Identified in Non-pathogenic and Pathogenic Entamoeba histolytica Clones Allow Identification of New Pathogenicity Factors Involved in Amoebic Liver Abscess Formation.

    PubMed

    Meyer, Martin; Fehling, Helena; Matthiesen, Jenny; Lorenzen, Stephan; Schuldt, Kathrin; Bernin, Hannah; Zaruba, Mareen; Lender, Corinna; Ernst, Thomas; Ittrich, Harald; Roeder, Thomas; Tannich, Egbert; Lotter, Hannelore; Bruchhaus, Iris

    2016-08-01

    We here compared pathogenic (p) and non-pathogenic (np) isolates of Entamoeba histolytica to identify molecules involved in the ability of this parasite to induce amoebic liver abscess (ALA)-like lesions in two rodent models for the disease. We performed a comprehensive analysis of 12 clones (A1-A12) derived from a non-pathogenic isolate HM-1:IMSS-A and 12 clones (B1-B12) derived from a pathogenic isolate HM-1:IMSS-B. "Non-pathogenicity" included the induction of small and quickly resolved lesions while "pathogenicity" comprised larger abscess development that overstayed day 7 post infection. All A-clones were designated as non-pathogenic, whereas 4 out of 12 B-clones lost their ability to induce ALAs in gerbils. No correlation between ALA formation and cysteine peptidase (CP) activity, haemolytic activity, erythrophagocytosis, motility or cytopathic activity was found. To identify the molecular framework underlying different pathogenic phenotypes, three clones were selected for in-depth transcriptome analyses. Comparison of a non-pathogenic clone A1np with pathogenic clone B2p revealed 76 differentially expressed genes, whereas comparison of a non-pathogenic clone B8np with B2p revealed only 19 differentially expressed genes. Only six genes were found to be similarly regulated in the two non-pathogenic clones A1np and B8np in comparison with the pathogenic clone B2p. Based on these analyses, we chose 20 candidate genes and evaluated their roles in ALA formation using the respective gene-overexpressing transfectants. We conclude that different mechanisms lead to loss of pathogenicity. In total, we identified eight proteins, comprising a metallopeptidase, C2 domain proteins, alcohol dehydrogenases and hypothetical proteins, that affect the pathogenicity of E. histolytica.

  2. Overexpression of Differentially Expressed Genes Identified in Non-pathogenic and Pathogenic Entamoeba histolytica Clones Allow Identification of New Pathogenicity Factors Involved in Amoebic Liver Abscess Formation

    PubMed Central

    Lorenzen, Stephan; Schuldt, Kathrin; Bernin, Hannah; Zaruba, Mareen; Lender, Corinna; Ittrich, Harald; Roeder, Thomas; Tannich, Egbert; Lotter, Hannelore; Bruchhaus, Iris

    2016-01-01

    We here compared pathogenic (p) and non-pathogenic (np) isolates of Entamoeba histolytica to identify molecules involved in the ability of this parasite to induce amoebic liver abscess (ALA)-like lesions in two rodent models for the disease. We performed a comprehensive analysis of 12 clones (A1–A12) derived from a non-pathogenic isolate HM-1:IMSS-A and 12 clones (B1–B12) derived from a pathogenic isolate HM-1:IMSS-B. “Non-pathogenicity” included the induction of small and quickly resolved lesions while “pathogenicity” comprised larger abscess development that overstayed day 7 post infection. All A-clones were designated as non-pathogenic, whereas 4 out of 12 B-clones lost their ability to induce ALAs in gerbils. No correlation between ALA formation and cysteine peptidase (CP) activity, haemolytic activity, erythrophagocytosis, motility or cytopathic activity was found. To identify the molecular framework underlying different pathogenic phenotypes, three clones were selected for in-depth transcriptome analyses. Comparison of a non-pathogenic clone A1np with pathogenic clone B2p revealed 76 differentially expressed genes, whereas comparison of a non-pathogenic clone B8np with B2p revealed only 19 differentially expressed genes. Only six genes were found to be similarly regulated in the two non-pathogenic clones A1np and B8np in comparison with the pathogenic clone B2p. Based on these analyses, we chose 20 candidate genes and evaluated their roles in ALA formation using the respective gene-overexpressing transfectants. We conclude that different mechanisms lead to loss of pathogenicity. In total, we identified eight proteins, comprising a metallopeptidase, C2 domain proteins, alcohol dehydrogenases and hypothetical proteins, that affect the pathogenicity of E. histolytica. PMID:27575775

  3. Spinal epidural abscess in brucellosis.

    PubMed

    Boyaci, Ahmet; Boyaci, Nurefsan; Tutoglu, Ahmet; Dokumaci, Dilek Sen

    2013-09-26

    Involvement of the skeletal system is a common complication of brucellosis. However, muscle involvement or paraspinal abscess formation are rare complications. Paraspinal abscess usually develops secondary to spondylitis. A case is reported here of a 33-year-old woman with symptoms of night sweats, fever and low back pain. Rose-Bengal test for brucellosis was positive and Brucella standard tube agglutination test was positive at a titre of 1/160. The diagnosis was made on MRI. The patient was treated with doxycycline and rifampin daily for 16 weeks. On day 14 of treatment, decline was observed in the patient's symptoms. In the presence of inflammatory lower back pain and fever, brucellosis should be considered particularly in the endemic areas. Furthermore, tuberculosis should be remembered in the differential diagnosis when a spinal epidural abscess is determined.

  4. Abscess - abdomen or pelvis

    MedlinePlus

    ... infected fluid and pus located inside the belly (abdominal cavity). This type of abscess can be located near ... abdominal abscesses: Abdominal x-ray Ultrasound of the abdomen and pelvis CT scan of the abdomen and ...

  5. Renal and perirenal abscesses

    SciTech Connect

    Patterson, J.E.; Andriole, V.T.

    1987-12-01

    Our knowledge of the spectrum of renal abscesses has increased as a result of more sensitive radiologic techniques. The classification of intrarenal abscess now includes acute focal bacterial nephritis and acute multifocal bacterial nephritis, as well as the previously recognized renal cortical abscess, renal corticomedullary abscess, and xanthogranulomatous pyelonephritis. In general, the clinical presentation of these entities does not differentiate them; various radiographic studies can distinguish them, however. The intrarenal abscess is usually treated successfully with antibiotic therapy alone. Antistaphylococcal therapy is indicated for the renal cortical abscess, whereas therapy directed against the common gram-negative uropathogens is indicated for most of the other entities. The perinephric abscess is often an elusive diagnosis, has a more serious prognosis, and is more difficult to treat. Drainage of the abscess and sometimes partial or complete nephrectomy are required for resolution. 73 references.

  6. Peritonsillar Abscess (For Teens)

    MedlinePlus

    ... mouth clean. But sometimes a peritonsillar abscess is beyond your control. If you think you have an abscess, call your doctor right away. ... ON THIS TOPIC Tonsils and Tonsillectomies Tonsillitis ...

  7. Paediatric Iliopsoas abscess: A case report.

    PubMed

    Elliott, Carla

    2013-11-01

    Introduction: Iliopsoas abscess is an uncommon condition in the paediatric population. The clinical presentation is variable and may be confused with other conditions such as septic arthritis, osteomyelitis and appendicular abscess. A suspicion of iliopsoas abscess requires a prompt diagnosis so that rapid management and treatment can be undertaken. Discussion: This case describes the presence of an iliopsoas abscess in a paediatric patient presenting to the emergency department within a rural community. Due to the variability in clinical presentation imaging studies are necessary to distinguish an iliopsoas abscess from other inflammatory processes. Ultrasound is often the modality of choice. Imaging guided percutaneous drainage and/or aspiration and the administration of intravenous antibiotics are minimally invasive modern techniques providing a safe treatment options in the presence of an iliopsoas abscess. Conclusion: Iliopsoas abscess is an uncommon condition in the paediatric population. Due to the variability in clinical presentation, imaging, and in particular, ultrasound play a vital role in the diagnosis of cases with a high suspicion of abscess formation. Accurate diagnosis leads to a rapid treatment plan, avoiding further insult.

  8. Recurrent sterile abscesses following aluminium adjuvant-containing vaccines.

    PubMed

    Klein, Nicola P; Edwards, Kathryn M; Sparks, Robert C; Dekker, Cornelia L

    2009-01-01

    Abscess formation following immunisation is a previously reported complication, generally associated with microbial contamination of the vaccine. Less commonly, such abscesses have been sterile. Here we describe two children evaluated in the Center for Disease Control and Prevention (CDC)-funded Clinical Immunization Safety Assessment (CISA) network who developed recurrent sterile abscesses after administration of vaccines containing aluminium adjuvant, either individually or in combination. Although the abscesses healed without sequelae, these occurrences support an association between receipt of aluminium adjuvant and sterile abscesses in susceptible patients. For patients with similar symptoms, clinicians may wish to choose a vaccine formulation containing the least amount of aluminium adjuvant.

  9. Non-traumatic nasal septal abscess in an immunocompetent patient.

    PubMed

    Salam, Badar; Camilleri, Andrew

    2009-12-01

    Nasal septal abscess is an uncommon condition. Most commonly it is secondary to nasal trauma, which leads to haematoma, and subsequent abscess formation. There are other less common causes like sinusitis, dental infections and furunculosis. Non-traumatic nasal septal abscess has also been reported in immunocompromised individuals. We report a case of non-traumatic, spontaneous nasal septal abscess, in a healthy immunocompetent patient with no evidence of sinusitis or other localized infections. Using Medline and Google.co.uk search applications, there has been one previous report of such a condition. We stress the importance of excluding nasal septal abscess in patients presenting with nasal obstruction especially with signs of toxaemia.

  10. Intravital two-photon microscopy of host-pathogen interactions in a mouse model of Staphylococcus aureus skin abscess formation.

    PubMed

    Liese, Jan; Rooijakkers, Suzan H M; van Strijp, Jos A G; Novick, Richard P; Dustin, Michael L

    2013-06-01

    Staphylococcus (S.) aureus is a frequent cause of severe skin infections. The ability to control the infection is largely dependent on the rapid recruitment of neutrophils (PMN). To gain more insight into the dynamics of PMN migration and host-pathogen interactions in vivo, we used intravital two-photon (2-P) microscopy to visualize S. aureus skin infections in the mouse. Reporter S. aureus strains expressing fluorescent proteins were developed, which allowed for detection of the bacteria in vivo. By employing LysM-EGFP mice to visualize PMN, we observed the rapid appearance of PMN in the extravascular space of the dermis and their directed movement towards the focus of infection, which led to the delineation of an abscess within 1 day. Moreover, tracking of transferred labelled bone-marrow neutrophils showed that PMN localization to the site of infection is dependent on the presence of G-protein-coupled receptors on the PMN, whereas Interleukin-1 receptor was required on host cells other than PMN. Furthermore, the S. aureus complement inhibitor Ecb could block PMN accumulation at thesite of infection. Our results establish that 2-P microscopy is a powerful tool to investigate the orchestration of the immune cells, S. aureus location and gene expression in vivo on a single cell level.

  11. [Prostatic abscesses. A review].

    PubMed

    Rabii, R; Rais, H; Joual, A; el Mrini, M; Benjelloun, S

    1999-01-01

    We review the literature to the diagnosis and therapeutic aspect of prostatic abscess. The prostatic abscess having become an uncommon disease. The diagnosis of prostatic abscess has been nearly made by transrectal ultrasound and computed tomography scan. The best diagnostic method is considered to be the transrectal ultrasound. The choice therapy was intravenous antibiotic, and drainage by ultrasound guided transperineal percutaneous puncture.

  12. The formation of gas-rich planets

    NASA Astrophysics Data System (ADS)

    Venturini, Julia; Helled, Ravit; Alibert, Yann; Benz, Willy

    2017-04-01

    The results of the Kepler mission show that planets smaller than Neptune ("mini-Neptunes"), presumably composed of non-negligible amounts of hydrogen and helium, are very frequent. The formation of this type of objects is challenging for the classical core-accretion paradigm for giant planet formation. I will show that mini-Neptunes are a natural outcome of the core accretion model when including the effect of envelope enrichment by icy planetesimals/pebbles in formation models. I will discuss as well how envelope enrichment affects the formation timescale, the planetary composition/structure, and the implications for the interpretation of exoplanet observations.

  13. Temperature gradient formation while axial gas compression

    NASA Astrophysics Data System (ADS)

    Geyko, V. I.; Fisch, N. J.

    2015-11-01

    A spinning gas in equilibrium has a rotation-dependent heat capacity. However, as equilibrium is approached, such as after sudden heating, significant variations in temperature appear. Surprisingly, when fast axial compression or instantaneous gas heating occurs, the temperature does not grow homogeneously in radial direction, but instead has a gradient towards to the maximum of potential energy of external or self potential. The gradient monotonically grows with compression rate and the amplitude of the potential. The gradient builds up due to change of equilibrium density distribution, yet, not due to acoustic waves created by the compression. This result was checked in numerical simulations for particles in an external constant gravitational potential and also for rotating gas in the cylinder with perfect slip boundary conditions on the walls. This work was supported by the U.S. Defense Threat Reduction Agency, and by the NNSA SSAA Program through DOE Research Grant No. DE-FG52-08NA28553.

  14. Method and apparatus for producing natural gas from tight formations

    SciTech Connect

    Bresie, D. A.; Burns, J. M.; Fowler, D. W.

    1984-10-30

    Natural gas wells in a tight formation area are drilled and completed with piping, the piping being capped with a Christmas tree. The piping is then utilized as a reservoir to collect natural gas from the tight formation over a prolonged time period. Mobile pressure vessel units are employed periodically to recover the collected natural gas, on a schedule designed for maximum economic efficiency. In the preferred embodiment, the reservoir is formed between the inner production tubing and the outer casing tubing, and conduits are connected to direct the natural gas from the production tubing into the reservoir. Liquid/gas separators and dehydrator units are employed on wells as necessary, so that the natural gas stored in the reservoir is ready for transport.

  15. Endogenous gas formation--an in vitro study with relevance to gas microemboli during cardiopulmonary bypass.

    PubMed

    Lindholm, Lena; Engström, Karl Gunnar

    2012-09-01

    Gas embolism is an identified problem during cardiopulmonary bypass (CPB). Our aim was to analyze the potential influence from gas solubility based on simple physical laws, here called endogenous gas embolism. Gas solubility decreases at higher temperature and gas bubbles are presumably formed at CPB warming. An experimental model to measure gas release was designed. Medium (water or blood retrieved from mediastinal drains, 14.6 mL) was incubated and equilibrated with gas (air, 100% oxygen, or 5% carbon dioxide in air) at low temperature (10 degrees C or 23 degrees C). At warming to 37 degrees C, gas release was digitally measured. Also, the effect of fluid motion was evaluated. At warming, the medium became oversaturated with dissolved gas. When fluid motion was applied, gas was released to form bubbles. This was exemplified by a gas release of .45% (.31/.54, medians and quartile range, volume percent, p = .007) and 1.26% (1.14/ 1.33, p = .003) when blood was warmed from 23 degrees C or 10 degrees C to 37 degrees C, respectively (carbon dioxide 5% in air). Consistent findings were seen for water and with the other types of gas exposure. The theory of endogenous gas embolization was confirmed with gas being released at warming. The endogenous gas formation demonstrated a dynamic pattern with oversaturation and with rapid gas released at fluid motion. The gas release at warming was substantial, in particular when the results were extrapolated to full-scale CPB conditions. The interference from endogenous gas formation should be considered in parallel to external sources of gas microemboli. cardiopulmonary bypass, gas embolization, microemboli, gas solubility, temperature.

  16. Modeling biogenic gas bubbles formation and migration in coarse sand

    NASA Astrophysics Data System (ADS)

    Ye, S.

    2011-12-01

    Shujun Ye Department of Hydrosciences, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210093, China; sjye@nju.edu.cn Brent E. Sleep Department of Civil Engineering, University of Toronto, Toronto, ON, M5S 1A4 CANADA; sleep@ecf.utoronto.ca Methane gas generation in porous media was investigated in an anaerobic two-dimensional sand-filled cell. Inoculation of the lower portion of the cell with a methanogenic culture and addition of methanol to the bottom of the cell led to biomass growth and formation of a gas phase. The formation, migration, distribution and saturation of gases in the cell were visualized by the charge-coupled device (CCD) camera. Gas generated at the bottom of the cell in the biologically active zone moved upwards in discrete fingers, so that gas phase saturations (gas-filled fraction of void space) in the biologically active zone at the bottom of the cell did not exceed 40-50%, while gas accumulation at the top of the cell produced gas phase saturations as high as 80%. Macroscopic invasion percolation (MIP) at near pore scale[Glass, et al., 2001; Kueper and McWhorter, 1992]was used to model gas bubbles growth in porous media. The nonwetting phase migration pathway can be yielded directly by MIP. MIP was adopted to simulate the expansion, fragmentation, and mobilization of gas clusters in the cell. The production of gas, and gas phash saturations were simulated by a continuum model - compositional simulator (COMPSIM) [Sleep and Sykes, 1993]. So a combination of a continuum model and a MIP model was used to simulate the formation, fragmentation and migration of biogenic gas bubbles. Key words: biogenic gas; two dimensional; porous media; MIP; COMPSIM

  17. Cryogenic target formation using cold gas jets

    DOEpatents

    Hendricks, C.D.

    1980-02-26

    A method and apparatus using cold gas jets for producing a substantially uniform layer of cryogenic materials on the inner surface of hollow spherical members having one or more layers, such as inertially imploded targets are disclosed. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on an inner surface of the spherical member. Basically the method involves directing cold gas jets onto a spherical member having one or more layers or shells and containing the cryogenic material, such as a deuterium-tritium (DT) mixture, to freeze the contained material, momentarily heating the spherical member so as to vaporize the contained material, and quickly refreezing the thus vaporized material forming a uniform layer of cryogenic material on an inner surface of the spherical member. 4 figs.

  18. Cryogenic target formation using cold gas jets

    DOEpatents

    Hendricks, Charles D. [Livermore, CA

    1980-02-26

    A method and apparatus using cold gas jets for producing a substantially uniform layer of cryogenic materials on the inner surface of hollow spherical members having one or more layers, such as inertially imploded targets. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on an inner surface of the spherical member. Basically the method involves directing cold gas jets onto a spherical member having one or more layers or shells and containing the cryogenic material, such as a deuterium-tritium (DT) mixture, to freeze the contained material, momentarily heating the spherical member so as to vaporize the contained material, and quickly refreezing the thus vaporized material forming a uniform layer of cryogenic material on an inner surface of the spherical member.

  19. Cryogenic target formation using cold gas jets

    DOEpatents

    Hendricks, Charles D.

    1981-01-01

    A method and apparatus using cold gas jets for producing a substantially uniform layer of cryogenic materials on the inner surface of hollow spherical members having one or more layers, such as inertially imploded targets. By vaporizing and quickly refreezing cryogenic materials contained within a hollow spherical member, a uniform layer of the materials is formed on an inner surface of the spherical member. Basically the method involves directing cold gas jets onto a spherical member having one or more layers or shells and containing the cryogenic material, such as a deuterium-tritium (DT) mixture, to freeze the contained material, momentarily heating the spherical member so as to vaporize the contained material, and quickly refreezing the thus vaporized material forming a uniform layer of cryogenic material on an inner surface of the spherical member.

  20. Ice-gas interactions during planet formation

    NASA Astrophysics Data System (ADS)

    Öberg, Karin I.

    2016-10-01

    Planets form in disks around young stars. In these disks, condensation fronts or snowlines of water, CO2, CO and other abundant molecules regulate the outcome of planet formation. Snowline locations determine how the elemental and molecular compositions of the gaseous and solid building blocks of planets evolve with distance from the central star. Snowlines may also locally increase the planet formation efficiency. Observations of snowlines have only become possible in the past couple of years. This proceeding reviews these observations as well as the theory on the physical and chemical processes in disks that affect snowline locations.

  1. Extended-Spectrum Cephalosporin Compared to Cefazolin for Treatment of Klebsiella pneumoniae-Caused Liver Abscess

    PubMed Central

    Cheng, Hsiao-Pei; Siu, L. K.; Chang, Feng-Yee

    2003-01-01

    From January 1995 to May 2000, a total of 107 adults with liver abscess due to Klebsiella pneumoniae admitted at a large medical center in northern Taiwan were reviewed. Patients were considered to have received cefazolin or an extended-spectrum cephalosporin if they received at least 3 days of that antibiotic within the first 5 days of hospitalization. Fifty-nine (55.1%) patients received cefazolin, and 48 (44.9%) patients received an extended-spectrum cephalosporin. The demographic data, clinical features, severities of illness, and rates of early drainage for the two groups were comparable. However, the rates of developing complications for the two groups were significantly different (37.3 versus 6.3%, respectively; P < 0.001). Furthermore, six independent factors preventing severe complications following liver abscess due to K. pneumoniae were identified: normal platelet count, alkaline phosphatase less than 300 U/liter, no gas formation in the abscess, APACHE III score less than 40, use of an extended-spectrum cephalosporin, and early drainage. In conclusion, cefazolin therapy may be suboptimal for patients with liver abscess due to K. pneumoniae despite active in vitro susceptibility. Use of an extended-spectrum cephalosporin and early drainage for patients with liver abscess due to K. pneumoniae are suggested. PMID:12821451

  2. [Morphological substantiation for the surgical treatment of chronic hepatic abscess].

    PubMed

    Kotenko, O G; Gomoliako, I V; Gusev, A V; Klochkova, N E; Petrishche, I I; Minich, A A

    2011-03-01

    The results of histological investigation, conducted in 27 patients, operated on for chronic hepatic abscess, are presented. Macroscopic and microscopic characteristic of all zones of hepatic affection is adduced, the mechanisms of formation of pyogenic membrane, zones of infiltration and fibrosis in chronic hepatic abscess formation are delineated.

  3. Formation of gas and ice giant planets

    NASA Astrophysics Data System (ADS)

    Boss, Alan P.

    2003-10-01

    The only presently known example of a planetary system containing a terrestrial planet in the habitable zone of a main sequence star is the Solar System. If the Solar System's giant planets formed by the generally assumed mechanism of core accretion, the Solar System probably formed in a relatively long-lived protoplanetary disk in a quiescent region of star formation, such as in the Taurus molecular cloud. However, if the giant planets formed by the more radical disk instability mechanism, then the Solar System would have formed in a region of high mass star formation, similar to the Orion Nebula Cluster or the Carina Nebula. In the latter case, the number of extrasolar planetary systems strongly resembling our own is likely to be significantly larger than in the former case, with important implications for the design of Darwin/TPF.

  4. Evolution of star formation and gas

    NASA Astrophysics Data System (ADS)

    Scoville, Nick Z.

    2013-10-01

    In these lectures I review observations of star-forming molecular clouds in our Galaxy and nearby galaxies to develop a physical intuition for understanding star formation in the local and high-redshift Universe. A lot of this material is drawn from early work in the field since much of the work was done two decades ago and this background is not generally available in the present literature. I also attempt to synthesise our well-developed understanding of star formation in low-redshift galaxies with constraints from theory and observations at high redshift to develop an intuitive model for the evolution of galaxy mass and luminosity functions in the early Universe. The overall goal of this contribution is to provide students with background helpful for analysis of far-infrared (FIR) observations from Herschel and millimetre/submillimetre (mm/submm) imaging with ALMA (the Atacama Large Millimetre/submillimetre Array). These two instruments will revolutionise our understanding of the interstellar medium (ISM) and associated star formation and galaxy evolution, both locally and in the distant Universe. To facilitate interpreting the FIR spectra of Galactic star-forming regions and high-redshift sources, I develop a model for the dust heating and radiative transfer in order to elucidate the observed infrared (IR) emissions. I do this because I am not aware of a similar coherent discussion in the literature.

  5. [Streptococcus intermedius: a rare cause of brain abscess in children].

    PubMed

    Jouhadi, Z; Sadiki, H; Hafid, I; Najib, J

    2013-03-01

    Streptococcus intermedius is a member of the Streptococcus anginosus group, also known as the Streptococcus milleri group. Although this is a commensal agent of the mouth and upper airways, it has been recognized as an important pathogen in the formation of abscesses. However, it has rarely been involved in the formation of brain abscess in children. We report 4 pediatric cases of brain abscess caused by S. intermedius. Three boys and 1 girl, all aged over 2 years, were admitted for a febrile meningeal syndrome and seizures, caused by a S. intermedius brain abscess. Diagnosis was obtained by brain imaging combined with culture of cerebrospinal fluid. The outcome was favorable after antibiotic therapy and abscess puncture. S. intermedius should be considered a potential pathogen involved in the development of brain abscess in children.

  6. Evolution of Dense Gas with Starburst Age: When Star Formation Versus Dense Gas Relations Break Down

    NASA Astrophysics Data System (ADS)

    Meier, David S.; Turner, J. L.; Schinnerer, E.

    2011-05-01

    Dense gas correlates well with star formation on kpc scales. On smaller scales, motions of individual clouds become comparable to the 100 Myr ages of starbursts. One then expects the star formation rate vs. dense gas relations to break down on giant molecular cloud scales. We exploit this to study the evolutionary history of nuclear starburst in the nearby spiral, IC 342. Maps of the J=5-4 and 16-15 transitions of dense gas tracer HC3N at 20 pc resolution made with the VLA and the Plateau de Bure interferometer are presented. The 5-4 line of HC3N traces very dense gas in the cold phase, while the 16-15 transition traces warm, dense gas. These reveal changes in dense cloud structure on scales of 30 pc among clouds with star formation histories differing by only a few Myrs. HC3N emission does not correlate well with young star formation at these high spatial resolutions, but gas excitation does. The cold, dense gas extends well beyond the starburst region implying large amounts of dense quiescent gas not yet actively forming stars. Close to the starburst the high excitation combined with faint emission indicates that the immediate (30 pc) vicinity of the starburst lacks large masses of very dense gas and has high dense gas star formation efficiencies. The dense gas appears to be in pressure equilibrium with the starburst. We propose a scenario where the starburst is being caught in the act of dispersing or destroying the dense gas in the presence of the expanding HII region. This work is supported by the NSF through NRAO and grant AST-1009620.

  7. Undiagnosed amebic brain abscess.

    PubMed

    Viriyavejakul, Parnpen; Riganti, Mario

    2009-11-01

    We report a case of amebic brain abscess due to Entamoeba histolytica. The patient was a 31-year-old man who presented with amebic liver abscess. His clinical course deteriorated in spite of proper drainage and treatment. He developed delirium, lethargy and then expired. With a history of heroin addiction, withdrawal syndrome from heroin was suspected. At autopsy, amebic abscesses were detected in the liver, large intestine, meninges and brain. A 19 cm amebic liver abscess was found in the right lobe of the liver. A 4 cm amebic brain abscess was found in the right occipital lobe. Microscopically, the tissue sections from the affected organs were confirmed to have degenerated E. histolytica trophozoites. Involvement of the brain in amebic liver abscess should be suspected in patients with neurological signs and symptoms.

  8. Hepatic hydatid cyst presenting as cutaneous abscess.

    PubMed

    Islam, M N; Khan, N A; Haque, S S; Hossain, M; Ahad, M A

    2012-01-01

    Hydatidosis is a parasitic zoonotic echinococcal infection that affects both humans and other mammals. These diseases are common worldwide but particularly common in sheep and cattle farming regions. Anaphylaxis mediated by IgE is a serious complication of surgery or trauma which necessitates more aware of its clinical features, diagnosis and management. It is important to make a preoperative diagnosis based on the typical image findings, so that particular precaution can be taken not to rupture the lesion. A woman presented with a right upper quadrant cutaneous abscess. USG reveals multiple cystic lesions in the liver arranged in cartwheel appearance, CT disclosed a cystic lesions having daughter cysts, marginal calcifications, marginal enhancement and contiguous abdominal wall abscess, which led to a diagnosis of complicated hepatic hydatid cysts with abdominal wall abscess formation. FNAC showed scolices surrounded by chronic inflammatory cells. Abdominal wall abscess may be a presentation of hydatid liver disease.

  9. Cold subcutaneous abscesses.

    PubMed Central

    Jackson, R.; Stephens, L.; Kelly, A. P.

    1990-01-01

    Cold abscesses are defined as having no associated erythema, heat, or tenderness. They may be present in immunodeficiency disorders, deep mycoses, and other infectious diseases. As there is a dearth information on this subject in the dermatology, surgery, and infectious disease literature, we present a case of cold abscesses secondary to coccidioidomycosis and discuss the possible role of humoral immunity, cell-mediated immunity, prostaglandins, T cells, and other mediators in cold abscess pathogenesis. In addition, therapeutic guidelines for abscesses are reviewed. Images Figure 1 Figure 2 PMID:2280425

  10. Porosity formation and gas bubble retention in laser metal deposition

    NASA Astrophysics Data System (ADS)

    Ng, G. K. L.; Jarfors, A. E. W.; Bi, G.; Zheng, H. Y.

    2009-11-01

    One of the inherent problems associated with laser metal deposition using gas-assisted powder transfer is the formation of porosity, which can be detrimental to the mechanical properties of the bulk material. In this work, a comprehensive investigation of porosity is carried out using gas atomised Inconel 718 powder. In the analysis, a clear distinction is made between two types of porosity; namely lack of fusion and gas porosity. The results show that the two types of porosity are attributed by different factors. The gas porosity, which is more difficult to eliminate than the lack of fusion, can be as high as 0.7%. The study shows that the gas porosity is dependent on the process parameters and the melt pool dynamics. The flotation of entrapped gas bubbles was analysed, showing that in a stationary melt pool the gas would be retained by Marangoni-driven flow. The overall Marangoni-driven flow of the melt pool is in the order of five times higher than the flotation effect, and this is the reason why the melt pool geometry would tend to dominate the flow direction of the gas bubbles. Through optimisation, the gas porosity can be reduced to 0.037%.

  11. Resonance Line Formation in Moving Gas Flows with High Porosity

    NASA Astrophysics Data System (ADS)

    Shulman, S. G.

    2017-06-01

    The formation of resonance lines in gas flows generated by interactions of circumstellar gas with a star's magnetosphere is examined. An effective method is proposed for calculating these lines when the magnetospheric wind is highly porous. The resonance sodium lines observed in the spectrum of UX Ori type star RZ Psc are modelled as an example. It is shown that the narrow absorptions observed in the short wavelength wings of these lines can be formed by scattering of the star's radiation in two gas jets that are semitransparent at the line frequencies when they cross the line of sight.

  12. THE DEPENDENCE OF STAR FORMATION EFFICIENCY ON GAS SURFACE DENSITY

    SciTech Connect

    Burkert, Andreas; Hartmann, Lee E-mail: lhartm@umich.edu

    2013-08-10

    Studies by Lada et al. and Heiderman et al. have suggested that star formation mostly occurs above a threshold in gas surface density {Sigma} of {Sigma}{sub c} {approx} 120 M{sub Sun} pc{sup -2} (A{sub K} {approx} 0.8). Heiderman et al. infer a threshold by combining low-mass star-forming regions, which show a steep increase in the star formation rate per unit area {Sigma}{sub SFR} with increasing {Sigma}, and massive cores forming luminous stars which show a linear relation. We argue that these observations do not require a particular density threshold. The steep dependence of {Sigma}{sub SFR}, approaching unity at protostellar core densities, is a natural result of the increasing importance of self-gravity at high densities along with the corresponding decrease in evolutionary timescales. The linear behavior of {Sigma}{sub SFR} versus {Sigma} in massive cores is consistent with probing dense gas in gravitational collapse, forming stars at a characteristic free-fall timescale given by the use of a particular molecular tracer. The low-mass and high-mass regions show different correlations between gas surface density and the area A spanned at that density, with A {approx} {Sigma}{sup -3} for low-mass regions and A {approx} {Sigma}{sup -1} for the massive cores; this difference, along with the use of differing techniques to measure gas surface density and star formation, suggests that connecting the low-mass regions with massive cores is problematic. We show that the approximately linear relationship between dense gas mass and stellar mass used by Lada et al. similarly does not demand a particular threshold for star formation and requires continuing formation of dense gas. Our results are consistent with molecular clouds forming by galactic hydrodynamic flows with subsequent gravitational collapse.

  13. Formation of Structured Water and Gas Hydrate by the Use of Xenon Gas in Vegetable Tissue

    NASA Astrophysics Data System (ADS)

    Ando, Hiroko; Suzuki, Toru; Kawagoe, Yoshinori; Makino, Yoshio; Oshita, Seiichi

    Freezing is a valuable technique for food preservation. However, vegetables are known to be softening remarkably after freezing and thawing process. It is expected to find alternative technique instead of freezing. Recently, the application of structured water and/or gas hydrate had been attempted to prolong the preservation of vegetable. In this study, the formation process of structure water and/or gas hydrate in pure water and carrot tissue was investigated by using NMR relaxation times, T1 and T2, of which applying condition was up to 0.4MPa and 0.8MPa at 5oC. Under the pressure of 0.4MPa, no gas hydrate was appeared, however, at 0.8MPa, formation of gas hydrate was recognized in both water and carrot tissue. Once the gas hydrate formation process in carrot tissue started, T1 and T2 increased remarkably. After that, as the gas hydrate developed, then T1 and T2 turned to decrease. Since this phenomenon was not observed in pure water, it is suggested that behavior of NMR relaxation time just after the formation of gas hydrate in carrot tissue may be peculiar to compartment system such as inter and intracellular spaces.

  14. Spinal epidural abscess.

    PubMed

    Miftode, E; Luca, V; Mihalache, D; Leca, D; Stefanidis, E; Anuţa, C; Sabadis, L

    2001-01-01

    In a retrospective study, 68 patients with Spinal Epidural Abscess (SEA) were reviewed. Of these, 66% had different predisposing factors such as staphylococcal skin infections, surgical procedures, rachicentesis, trauma, spondilodiscitis. Abscess had a lumbar region location in 53% of cases. Staphylococcus aureus was the most frequent etiological agent (81%). The overall rate of mortality in SEA patients was 13.2%.

  15. Anal abscess and fistula.

    PubMed

    Sneider, Erica B; Maykel, Justin A

    2013-12-01

    Benign anorectal diseases, such as anal abscesses and fistula, are commonly seen by primary care physicians, gastroenterologists, emergency physicians, general surgeons, and colorectal surgeons. It is important to have a thorough understanding of the complexity of these 2 disease processes so as to provide appropriate and timely treatment. We review the pathophysiology, presentation, diagnosis, and treatment options for both anal abscesses and fistulas.

  16. Citrobocter kasori spinal epidural abscess: a rare occurrence.

    PubMed

    Kumar, Ashok; Jain, Pramod; Singh, Pritish; Divthane, Rupam; Badole, C M

    2013-01-01

    Pyogenic spinal epidural abscess Is an uncommon Infectious occurrence. Clinical prospects of pyogenic spinal epidural abscess are graver if not promptly diagnosed and treated appropriately. A case of spinal epidural abscess has been presented with sinus tract formation at L4-L5 level, of pyogenic aetiology that progressed to paraplegia over the course of the disease. MRI pointed towards an epidural abscess extending from T12 vertebral level to S1 vertebral level. Surgical decompression in the form of laminectomy and evacuation of pus was done and antibiotics were given according to culture and sensitivity. Histopathological analysis revealed the acute suppurative nature of the abscess. Citrobacter kasori was isolated on pus culture. Pyogenic epidural abscess with causative organism being Citrobacter kasori has least been documented.

  17. Entamoeba histolytica brain abscess.

    PubMed

    Petri, William A; Haque, Rashidul

    2013-01-01

    Brain abscess due to Entamoeba histolytica is most commonly seen in a small percentage of patients who also have an amebic liver abscess. The typical patient is a young man who after treatment for liver abscess with apparent improvement develops symptoms and signs of central nervous system involvement. The average age of the patient is 30 years, and common presentations include headache, vomiting, and altered mental status. Signs of amebic brain abscess include most commonly meningeal signs, facial nerve (VII) palsy, motor paralysis, and seizure. Most patients have abnormal cerebrospinal fluid although there is no special or characteristic abnormality. Diagnosis is by serology and PCR of brain abscess aspirate or CSF and treatment is with metronidazole. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. New hydrate formation methods in a liquid-gas medium

    PubMed Central

    Chernov, A. A.; Pil’nik, A. A.; Elistratov, D. S.; Mezentsev, I. V.; Meleshkin, A. V.; Bartashevich, M. V.; Vlasenko, M. G.

    2017-01-01

    Conceptually new methods of hydrate formation are proposed. The first one is based on the shock wave impact on a water-bubble medium. It is shown that the hydrate formation rate in this process is typically very high. A gas hydrate of carbon dioxide was produced. The process was experimentally studied using various initial conditions, as well as different external action magnitudes. The obtained experimental data are in good agreement with the proposed model. Other methods are based on the process of boiling liquefied gas in an enclosed volume of water (explosive boiling of a hydrating agent and the organization of cyclic boiling-condensation process). The key features of the methods are the high hydrate formation rate combined with a comparatively low power consumption leading to a great expected efficiency of the technologies based on them. The set of experiments was carried out. Gas hydrates of refrigerant R134a, carbon dioxide and propane were produced. The investigation of decomposition of a generated gas hydrate sample was made. The criteria of intensification of the hydrate formation process are formulated. PMID:28098194

  19. New hydrate formation methods in a liquid-gas medium

    NASA Astrophysics Data System (ADS)

    Chernov, A. A.; Pil'Nik, A. A.; Elistratov, D. S.; Mezentsev, I. V.; Meleshkin, A. V.; Bartashevich, M. V.; Vlasenko, M. G.

    2017-01-01

    Conceptually new methods of hydrate formation are proposed. The first one is based on the shock wave impact on a water-bubble medium. It is shown that the hydrate formation rate in this process is typically very high. A gas hydrate of carbon dioxide was produced. The process was experimentally studied using various initial conditions, as well as different external action magnitudes. The obtained experimental data are in good agreement with the proposed model. Other methods are based on the process of boiling liquefied gas in an enclosed volume of water (explosive boiling of a hydrating agent and the organization of cyclic boiling-condensation process). The key features of the methods are the high hydrate formation rate combined with a comparatively low power consumption leading to a great expected efficiency of the technologies based on them. The set of experiments was carried out. Gas hydrates of refrigerant R134a, carbon dioxide and propane were produced. The investigation of decomposition of a generated gas hydrate sample was made. The criteria of intensification of the hydrate formation process are formulated.

  20. New hydrate formation methods in a liquid-gas medium.

    PubMed

    Chernov, A A; Pil'nik, A A; Elistratov, D S; Mezentsev, I V; Meleshkin, A V; Bartashevich, M V; Vlasenko, M G

    2017-01-18

    Conceptually new methods of hydrate formation are proposed. The first one is based on the shock wave impact on a water-bubble medium. It is shown that the hydrate formation rate in this process is typically very high. A gas hydrate of carbon dioxide was produced. The process was experimentally studied using various initial conditions, as well as different external action magnitudes. The obtained experimental data are in good agreement with the proposed model. Other methods are based on the process of boiling liquefied gas in an enclosed volume of water (explosive boiling of a hydrating agent and the organization of cyclic boiling-condensation process). The key features of the methods are the high hydrate formation rate combined with a comparatively low power consumption leading to a great expected efficiency of the technologies based on them. The set of experiments was carried out. Gas hydrates of refrigerant R134a, carbon dioxide and propane were produced. The investigation of decomposition of a generated gas hydrate sample was made. The criteria of intensification of the hydrate formation process are formulated.

  1. Neck abscess: 79 cases

    PubMed Central

    Bulgurcu, Suphi; Arslan, Ilker Burak; Demirhan, Erhan; Kozcu, Sureyya Hikmet; Cukurova, Ibrahim

    2015-01-01

    OBJECTIVE: Neck abscess is a disease that might cause mortality and severe morbidity, if it is not treated urgently. In our study, patients with diagnosis of neck abscess in our clinic were analyzed retrospectively and presented in the light of the literature. METHODS: In our clinic, age distribution, source of infection, systemic disease, imaging methods that were used in diagnosis, preferred anaesthesia during drainage, abscess sites, culture results of abscess material, complications during treatment procedure, any antibiotherapy before admission and duration of hospitalization of 79 cases with neck abscess who were treated in the hospital between January 2008 and January 2015 were assessed. RESULTS: Cases in our study were aged between 1–79 (mean 28.3) years and 43 of them were female and 36 were male patients. Systemic diseases were determined in 19 of the cases. The most common systemic disease was diabetes mellitus. Abscesses were localized mostly at peritonsillar region and 13 of the cases were operated when abscess were in multipl localizations. In 74 of the cases, drainage was performed under local anaesthesia and in 5 cases under general anaesthesia. Four of these 5 cases, abscesses were localized within retropharyngeal region and 1 of them had multiple abscesses at various regions. Staphylococcus aereus was the most detected microorganism based on culture results. Three adult cases were followed up in the intensive care unit because of development of mediastinitis. One of these 3 cases exited because of sepsis. Hospitalization periods of 79 cases ranged between 2–21 days (mean 7.64 days). Hospitalization period of 19 cases with systemic diseases were 9.47 days (p<0.05) and statistically which were statistically significantly longer when compared with those without any systemic disease. CONCLUSION: Neck abscess must be diagnosed early and treated with surgical drainage and parenteral therapy because it might cause severe complications. PMID:28058371

  2. Star formation and gas phase history of the cosmic web

    NASA Astrophysics Data System (ADS)

    Snedden, Ali; Coughlin, Jared; Phillips, Lara Arielle; Mathews, Grant; Suh, In-Saeng

    2016-01-01

    We present a new method of tracking and characterizing the environment in which galaxies and their associated circumgalactic medium evolve. We have developed a structure finding algorithm that uses the rate of change of the density gradient to self-consistently parse and follow the evolution of groups/clusters, filaments and voids in large-scale structure simulations. We use this to trace the complete evolution of the baryons in the gas phase and the star formation history within each structure in our simulated volume. We vary the structure measure threshold to probe the complex inner structure of star-forming regions in poor clusters, filaments and voids. We find that the majority of star formation occurs in cold, condensed gas in filaments at intermediate redshifts (z ˜ 3). We also show that much of the star formation above a redshift z = 3 occurs in low-contrast regions of filaments, but as the density contrast increases at lower redshift, star formation switches to the high-contrast regions, or inner parts, of filaments. Since filaments bridge the void and cluster regions, it suggests that the majority of star formation occurs in galaxies in intermediate density regions prior to the accretion on to groups/clusters. We find that both filaments and poor clusters are multiphase environments distinguishing themselves by different distributions of gas phases.

  3. Separation of SF6 from gas mixtures using gas hydrate formation.

    PubMed

    Cha, Inuk; Lee, Seungmin; Lee, Ju Dong; Lee, Gang-woo; Seo, Yongwon

    2010-08-15

    This study aims to examine the thermodynamic feasibility of separating sulfur hexafluoride (SF(6)), which is widely used in various industrial fields and is one of the most potent greenhouse gases, from gas mixtures using gas hydrate formation. The key process variables of hydrate phase equilibria, pressure-composition diagram, formation kinetics, and structure identification of the mixed gas hydrates, were closely investigated to verify the overall concept of this hydrate-based SF(6) separation process. The three-phase equilibria of hydrate (H), liquid water (L(W)), and vapor (V) for the binary SF(6) + water mixture and for the ternary N(2) + SF(6) + water mixtures with various SF(6) vapor compositions (10, 30, 50, and 70%) were experimentally measured to determine the stability regions and formation conditions of pure and mixed hydrates. The pressure-composition diagram at two different temperatures of 276.15 and 281.15 K was obtained to investigate the actual SF(6) separation efficiency. The vapor phase composition change was monitored during gas hydrate formation to confirm the formation pattern and time needed to reach a state of equilibrium. Furthermore, the structure of the mixed N(2) + SF(6) hydrate was confirmed to be structure II via Raman spectroscopy. Through close examination of the overall experimental results, it was clearly verified that highly concentrated SF(6) can be separated from gas mixtures at mild temperatures and low pressure conditions.

  4. Bacterial Brain Abscess

    PubMed Central

    Patel, Kevin

    2014-01-01

    Significant advances in the diagnosis and management of bacterial brain abscess over the past several decades have improved the expected outcome of a disease once regarded as invariably fatal. Despite this, intraparenchymal abscess continues to present a serious and potentially life-threatening condition. Brain abscess may result from traumatic brain injury, prior neurosurgical procedure, contiguous spread from a local source, or hematogenous spread of a systemic infection. In a significant proportion of cases, an etiology cannot be identified. Clinical presentation is highly variable and routine laboratory testing lacks sensitivity. As such, a high degree of clinical suspicion is necessary for prompt diagnosis and intervention. Computed tomography and magnetic resonance imaging offer a timely and sensitive method of assessing for abscess. Appearance of abscess on routine imaging lacks specificity and will not spare biopsy in cases where the clinical context does not unequivocally indicate infectious etiology. Current work with advanced imaging modalities may yield more accurate methods of differentiation of mass lesions in the brain. Management of abscess demands a multimodal approach. Surgical intervention and medical therapy are necessary in most cases. Prognosis of brain abscess has improved significantly in the recent decades although close follow-up is required, given the potential for long-term sequelae and a risk of recurrence. PMID:25360205

  5. Galaxy chemical evolution models: the role of molecular gas formation

    NASA Astrophysics Data System (ADS)

    Mollá, Mercedes; Díaz, Ángeles I.; Ascasibar, Yago; Gibson, Brad K.

    2017-06-01

    In our classical grid of multiphase chemical evolution models, star formation in the disc occurs in two steps: first, molecular gas forms, and then stars are created by cloud-cloud collisions or interactions of massive stars with the surrounding molecular clouds. The formation of both molecular clouds and stars are treated through the use of free parameters we refer to as efficiencies. In this work, we modify the formation of molecular clouds based on several new prescriptions existing in the literature, and we compare the results obtained for a chemical evolution model of the Milky Way Galaxy regarding the evolution of the Solar region, the radial structure of the Galactic disc and the ratio between the diffuse and molecular components, H i/H2. Our results show that the six prescriptions we have tested reproduce fairly consistent most of the observed trends, differing mostly in their predictions for the (poorly constrained) outskirts of the Milky Way and the evolution in time of its radial structure. Among them, the model proposed by Ascasibar et al. (in preparation), where the conversion of diffuse gas into molecular clouds depends on the local stellar and gas densities as well as on the gas metallicity, seems to provide the best overall match to the observed data.

  6. A Gas-phase Formation Route to Interstellar Trans-methyl Formate

    NASA Astrophysics Data System (ADS)

    Cole, Callie A.; Wehres, Nadine; Yang, Zhibo; Thomsen, Ditte L.; Snow, Theodore P.; Bierbaum, Veronica M.

    2012-07-01

    The abundance of methyl formate in the interstellar medium has previously been underpredicted by chemical models. Additionally, grain surface chemistry cannot account for the relative abundance of the cis- and trans-conformers of methyl formate, and the trans-conformer is not even formed at detectable abundance on these surfaces. This highlights the importance of studying formation pathways to methyl formate in the gas phase. The rate constant and branching fractions are reported for the gas-phase reaction between protonated methanol and formic acid to form protonated trans-methyl formate and water as well as adduct ion: Rate constants were experimentally determined using a flowing afterglow-selected ion flow tube apparatus at 300 K and a pressure of 530 mTorr helium. The results indicate a moderate overall rate constant of (3.19 ± 0.39) × 10-10 cm3 s-1 (± 1σ) and an average branching fraction of 0.05 ± 0.04 for protonated trans-methyl formate and 0.95 ± 0.04 for the adduct ion. These experimental results are reinforced by ab initio calculations at the MP2(full)/aug-cc-pVTZ level of theory to examine the reaction coordinate and complement previous density functional theory calculations. This study underscores the need for continued observational studies of trans-methyl formate and for the exploration of other gas-phase formation routes to complex organic molecules.

  7. Cloud-particle galactic gas dynamics and star formation

    NASA Technical Reports Server (NTRS)

    Roberts, W. W., Jr.

    1983-01-01

    Galactic gas dynamics, spiral structure, and star formation are discussed in relation to N-body computational studies based on a cloud-particle model of the interstellar medium. On the small scale, the interstellar medium is seen as cloud-dominated and supernova-perturbed. It is noted that the cloud-particle model simulates cloud-cloud collisions, the formation of stellar associations, and supernova explosions as dominant local processes. On the large scale, in response to a spiral galactic gravitational field, global density waves and galactic shocks develop having large-scale characteristics similar to those found in continuum gas dynamical studies. Both the system of gas clouds and the system of young stellar associations forming from the clouds figure in the global spiral structure. However, with the attributes of neither assuming a continuum of gas (as in continuum gas dynamical studies) or requiring a prescribed equation of state (such as the isothermal condition), the cloud-particle picture retains much of the detail lost in earlier work. By detail is meant the small-scale features and structures so important in understanding the local, turbulent state of the interstellar medium as well as the degree of raggedness often seen to be superposed on the global spiral structure.

  8. Rapid formation of molecular clouds from turbulent atomic gas

    NASA Astrophysics Data System (ADS)

    Glover, S. C. O.; Mac Low, M.-M.

    The characteristic lifetimes of molecular clouds remain uncertain and a topic of frequent debate, with arguments having recently been advanced both in support of short-lived clouds, with lifetimes of a few Myr or less (see e.g. Elmegreen 2000; Hartmann et al. 2001) and in support of much longer-lived clouds, with lifetimes of the order of 10 Myr or more (see e.g. Tassis & Mouschovias, 2004; Goldsmith & Li, 2005). An argument that has previously been advanced in favour of longer lived clouds is the apparent difficulty involved in converting sufficient atomic hydrogen to molecular hydrogen within the short timescale required by the rapid cloud formation scenario. However, previous estimates of the time required for this conversion to occur have not taken into account the effects of the supersonic turbulence which is inferred to be present in the atomic gas. In this contribution, we present results from a set of high resolution three-dimensional simulations of turbulence in gravitationally unstable atomic gas. These simulations were performed using a modified version of the ZEUS-MP hydrodynamical code (Norman 2000), and include a detailed treatment of the thermal balance of the gas and of the formation of molecular hydrogen. The effects of photodissociation of H2 by the Galactic UV field are also included, with a simple local approximation used to compute the effects of H2 self-shielding. The results of our simulations demonstrate that H2 formation occurs rapidly in turbulent atomic gas. Starting from purely atomic gas, large quantities of molecular gas can be produced on timescales of less than a Myr, given turbulent velocity dispersions and magnetic field strengths consistent with observations. Moreover, as our simulations underestimate the effectiveness of H2 self-shielding and dust absorption, we can be confident that the molecular fractions which we compute are strong lower limits on the true values. The formation of large quantities of molecular gas on the

  9. Computed tomographic evaluation of an experimental model for pyogenic liver abscesses.

    PubMed

    Thompson, W M; Stude, R A; McDonald, M I; Halvorsen, R A; Dunnick, N R; Silverman, P M; Korobkin, M; Durack, D T; Shelbourne, J

    1985-01-01

    Computed tomography (CT) was used to evaluate 15 rabbits with experimentally induced liver abscesses. The animals were examined both before and after intravenous contrast injection. After sacrificing the animals, postfreeze CT scans were made to mark the abdomen for 1-cm thick whole body sections for correlating the gross pathology with the results of the CT scans. CT detected 15 abscesses in 13 of the 14 rabbits with true positive lesions. Ten abscesses less than 1.4 cm in diameter were not detected by CT. Contrast agent enhancement was helpful in 70% of the studies. These abscesses have characteristics similar to human liver abscesses, but there was more gas and calcium in the experimentally induced abscesses than is encountered in humans with hepatic abscesses. The model and its CT characteristics appear well suited for future studies in the diagnosis and treatment of liver abscesses.

  10. [Surgical treatment of a solitary hepatic abscess].

    PubMed

    Boĭko, V V; Tishchenko, A M; Gusak, I V; Maloshtan, A A; Skoryĭ, D I; Smachilo, R M

    2013-06-01

    Retrospective analysis of the treatment results of 120 patients, suffering solitary hepatic abscess (SHA), was conducted. The sanation methods, in accordance to technology, the treatment impact intensity and aggressiveness, may be divided on three lines: aspirational, draining and resectional. The method of sanation is selected on the background of morphological peculiarities of abscess--its sizes, by presence of sequesters, divisioning septs, dense rigid capsule, grade of periprocess. Surgical access is determined by the abscess localization, the patient's state severity, instrumental equipment of the clinic. Differentiated approach, taking into account genesis, sizes, localization and stage of its formation, constitutes a background of successful treatment of SHA. In totally formatted acute SHA, as a rule, the methods of choice are aspirational and aspiration-draining methods of sanation under ultrasonographic control or laparoscopy. In the presence of chronic SHA or suppurated parasitic hepatic cyst it is mandatory to select the resectional methods.

  11. Gravitational star formation thresholds and gas density in three galaxies

    NASA Technical Reports Server (NTRS)

    Oey, M. S.; Kennicutt, R. C., Jr.

    1990-01-01

    It has long been held that the star formation rate (SFR) may be described as a power law of the gas density, p(exp n), as given by Schmidt (1959). However, this relation has as yet remained poorly defined and is likewise poorly understood. In particular, most studies have been investigations of global gas and star formation properties of galaxies, due to lack of adequate high-resolution data for detailed studies of individual galaxies. The three spiral galaxies in this study have published maps of both H2 (as traced by CO), and HI, thereby enabling the authors to investigate the relationship between total gas surface density and SFR. The purpose of the present investigation is the comparison of spatially-resolved total surface gas density in three galaxies (NGC 6946, M51, and M83) to sigma sub c as given by the above model. CO, HI and H alpha data for NGC 6946 were taken from Tacconi-Garman (1988), and for M51 and M83 from Lord (1987). The authors used a CO-H2 conversion of N(H2)/I sub CO(exp cos i = 2.8 x 10(exp 20) atoms cm(-2)/(K kms(-1), and summed the H2 and HI data for each galaxy to obtain the total hydrogen gas density. This total was then multiplied by a factor of 1.36 to include the contribution of helium to the total surface gas density. The authors assumed distances to NGC 6946, M51, and M83 to be 6.0, 9.6, and 8.9 Mpc respectively, with inclination angles of 30, 20, and 26 degrees. H alpha flux was used as the measure of SFR for NGC 6946, and SFR for the remaining two galaxies was taken directly from Lord as computed from H alpha measurements. The results of these full-disk studies thus show a remarkable correlation between the total gas density and the threshold densities given by the gravitational stability criterion. In particular, the threshold density appears to mark a lower boundary to the range of gas densities in these galaxies, which may have consequence in determining appropriate models for star formation and gas dynamics. More evidence is

  12. Molecular Gas and Star Formation in Atomic Gas Dominated Regions - Results from the HERACLES Survey

    NASA Astrophysics Data System (ADS)

    Schruba, Andreas; Leroy, A. K.; Walter, F.; HERACLES Team

    2012-01-01

    We perform a sensitive search for faint CO emission and study how it is related to star formation in HI-dominated regions of 45 nearby spiral and dwarf galaxies using observations of CO (HERACLES), HI (THINGS), IR & Halpha (SINGS/LVL), and UV (GALEX NGS). Constraining the molecular gas content in HI-dominated regions is a crucial measurement to distinguish the role of atomic and molecular gas in the star formation process. We apply a novel technique, leveraging HI velocity fields from THINGS and wide area coverage of HERACLES to stack CO spectra and significantly increase the sensitivity. For spiral galaxies, CO (and thus H2) is linearly related to tracers of star formation (IR, Halpha, FUV) and does not depend on gas density. Meanwhile, the H2-to-HI ratio varies by several orders of magnitude with radius and total gas surface density and thus sensitively regulates the supply of star-forming molecular gas. For dwarf galaxies, we determine sensitive upper limits on the CO luminosity both near star-forming peaks and the entire galaxy and find CO emission to be faint both in an absolute sense and normalized by B-band luminosity and star formation rate (SFR). The ratio SFR/CO increases by more than an order of magnitude toward low metallicities which likely indicates a dramatic increase in the CO-to-H2 conversion factor.

  13. Rapid gas hydrate formation processes: Will they work?

    SciTech Connect

    Brown, Thomas D.; Taylor, Charles E.; Bernardo, Mark P.

    2010-06-07

    Researchers at DOE’s National Energy Technology Laboratory (NETL) have been investigating the formation of synthetic gas hydrates, with an emphasis on rapid and continuous hydrate formation techniques. The investigations focused on unconventional methods to reduce dissolution, induction, nucleation and crystallization times associated with natural and synthetic hydrates studies conducted in the laboratory. Numerous experiments were conducted with various high-pressure cells equipped with instrumentation to study rapid and continuous hydrate formation. The cells ranged in size from 100 mL for screening studies to proof-of-concept studies with NETL’s 15-Liter Hydrate Cell. The results from this work demonstrate that the rapid and continuous formation of methane hydrate is possible at predetermined temperatures and pressures within the stability zone of a Methane Hydrate Stability Curve.

  14. Rapid gas hydrate formation processes: Will they work?

    DOE PAGES

    Brown, Thomas D.; Taylor, Charles E.; Bernardo, Mark P.

    2010-06-07

    Researchers at DOE’s National Energy Technology Laboratory (NETL) have been investigating the formation of synthetic gas hydrates, with an emphasis on rapid and continuous hydrate formation techniques. The investigations focused on unconventional methods to reduce dissolution, induction, nucleation and crystallization times associated with natural and synthetic hydrates studies conducted in the laboratory. Numerous experiments were conducted with various high-pressure cells equipped with instrumentation to study rapid and continuous hydrate formation. The cells ranged in size from 100 mL for screening studies to proof-of-concept studies with NETL’s 15-Liter Hydrate Cell. The results from this work demonstrate that the rapid and continuousmore » formation of methane hydrate is possible at predetermined temperatures and pressures within the stability zone of a Methane Hydrate Stability Curve.« less

  15. [Cerebellar abscesses secondary to infection of an occipital dermal sinus].

    PubMed

    García Galera, A; Martínez León, M I; Pérez da Rosa, S; Ros López, B

    2013-09-01

    A dermal sinus is a congenital defect arising from a closure failure of the neural tube that results in different degrees of communication between the skin and the central nervous system. A dermal sinus can occur anywhere from the root of the nose to the conus medullaris, and the occipital location is the second most common. Dermal sinuses are often found in association with dermoid or epidermoid cysts and less frequently with teratomas. Patients with an occipital dermoid cyst associated with a dermal sinus can develop meningitis and/or abscesses as the first clinical manifestation of the disease due to the dermoid cyst itself becoming abscessed or to the formation of secondary abscesses; few cases of the formation of secondary abscesses have been reported. We present a case of a dermoid cyst associated with an infected dermal sinus and posterior development of cerebellar abscesses and hydrocephalus.

  16. Gas phase dynamics of triplet formation in benzophenone.

    PubMed

    Spighi, Gloria; Gaveau, Marc-André; Mestdagh, Jean-Michel; Poisson, Lionel; Soep, Benoît

    2014-05-28

    Benzophenone is a prototype molecule for photochemistry in the triplet state through its high triplet yield and reactivity. We have investigated its dynamics of triplet formation under the isolated gas phase conditions via femtosecond and nanosecond time resolved photoelectron spectroscopy. This represents the complete evolution from the excitation in S2 to the final decay of T1 to the ground state S0. We have found that the triplet formation can be described almost as a direct process in preparing T1, the lowest reacting triplet state, from the S1 state after S2 → S1 internal conversion. The molecule was also deposited by a pick-up technique on cold argon clusters providing a soft relaxation medium without evaporation of the molecule and the mechanism was identical. This cluster technique is a model for medium influenced electronic relaxation and provides a continuous transition from the isolated gas phase to the relaxation dynamics in solution.

  17. Chondrule Formation: Nebular Gas Confinement of Impact Splashes

    NASA Astrophysics Data System (ADS)

    Dullemond, Cornelis Petrus; Johansen, Anders

    2013-07-01

    We show that the impact debris from a high-speed collision between two planetesimals during the first few million years would sweep up the nebular gas as a snow plow, leading to deceleration and compression of the debris into a thin shell. This shell breaks up into dense bullets through the Rayleigh-Taylor instability. As a result of the compression by the gas, these bullets will have super-Roche densities and thus will gravitationally collapse to form new planetesimals. Chondrules that may have formed from impact melting would thus rapidly be reaccreted into planetesimals. These dense environments are ideal for forming compound chondrules. The hydrodynamic interaction with the nebular gas could lead to mixing between the newly formed chondrules and surviving pre-impact material. Volatiles can be exchanged between these components in the dense bullets, allowing for chemical complementarity. We believe that this scenario may have some advantages over earlier impact scenarios for chondrule formation.

  18. Anorectal abscess during pregnancy.

    PubMed

    Koyama, Shinsuke; Hirota, Masaki; Kobayashi, Masaki; Tanaka, Yusuke; Kubota, Satoshi; Nakamura, Ryo; Isobe, Masanori; Shiki, Yasuhiko

    2014-02-01

    Anorectal symptoms and complaints caused by hemorrhoids or anal fissures are common during pregnancy. It is known that one-third of pregnant women complain of anal pain in the third trimester. Anal pain may be caused by a wide spectrum of conditions, but if it begins gradually and becomes excruciating within a few days it may indicate anorectal abscess. We experienced a case of anorectal abscess during pregnancy which was diagnosed by magnetic resonance imaging and treated by incision and seton drainage at 36 weeks of gestation, followed by a normal spontaneous delivery at 38 weeks of gestation. To our knowledge, this is the first case report of anorectal abscess during pregnancy in the English-language published work. The clinical course of our case and clinical considerations of anorectal abscesses are discussed.

  19. Peritonsillar Abscess (For Teens)

    MedlinePlus

    ... doctors use antibiotics to treat tonsillitis. Tooth and gum disease can increase the chances of a peritonsillar abscess ... Tonsillitis Strep Throat How Can I Quit Smoking? Gum Disease Stop Smoking: Your Personal Plan Mouth and Teeth ...

  20. Abscess in the Lungs

    MedlinePlus

    ... a sample of sputum and try to grow (culture) the organism causing the abscess, but this test ... obtain samples of lung secretions or tissue for culture if, for example, Antibiotics seem ineffective Obstruction of ...

  1. Legionella micdadei Brain Abscess

    PubMed Central

    Johnson, Edward; Macyk-Davey, Andrea; Henry, Monica; Nilsson, Jan-Erik; Miedzinski, Lil

    2013-01-01

    We describe an immunocompromised patient who developed a large frontal brain abscess caused by Legionella micdadei. This is, to our knowledge, a rare case of culture-proven Legionella central nervous system infection. PMID:23224082

  2. Tonsillar Cellulitis and Abscess

    MedlinePlus

    ... to Pneumococcal Vaccine Additional Content Medical News Tonsillar Cellulitis and Tonsillar Abscess By Clarence T. Sasaki, MD, ... Vocal Cord Contact Ulcers Vocal Cord Paralysis Tonsillar cellulitis is a bacterial infection of the tissues around ...

  3. Percutaneous hepatic abscess drainage: do multiple abscesses or multiloculated abscesses preclude drainage or affect outcome?

    PubMed

    Liu, Chang-Hsien; Gervais, Debra A; Hahn, Peter F; Arellano, Ronald S; Uppot, Raul N; Mueller, Peter R

    2009-08-01

    To compare the effectiveness of percutaneous abscess drainage in patients with pyogenic liver abscesses of the following types: single, single multiloculated, multiple, and multiple multiloculated. One hundred nine patients with 149 liver abscesses who underwent percutaneous drainage during an 11-year period were divided into a single abscess group and a multiple abscess group. Of the 109 patients, 54 had multiloculated abscesses and were divided into single and multiple multiloculated abscess groups. Technical success was defined as the ability to place the catheter within the abscess cavity and clinical success was defined as improvement in the patient's symptoms. Clinical findings, management strategy, complication rate, and success rate were analyzed. Technical success rates were 96% (82 of 85) for a single abscess and 96% (23 of 24) for multiple abscesses (P = 1.0). Clinical success was achieved in 74 of 85 patients (87%) with a single abscess and 22 of 24 patients (92%) with multiple abscesses (P = .729). Technical success rates were 94% (32 of 34) for a single multiloculated abscess and 95% (19 of 20) for multiple multiloculated abscesses (P = 1.0). Clinical success was achieved in 30 of 34 patients (88%) with a single multiloculated abscess and 18 of 20 patients (90%) with multiple multiloculated abscesses (P = 1). No significant difference in hospital stay was seen between single and multiple abscess groups (P = .373) or between single multiloculated and multiple multiloculated abscess groups (P = .180). There were no major complications or mortality related to the procedure. Percutaneous drainage is a safe and effective procedure in the treatment of pyogenic liver abscess, regardless of abscess complexity and/or multiplicity.

  4. Formation of Long-Lived Gas Species in Hydrogen Thyratrons

    DTIC Science & Technology

    1981-06-01

    16.6 FOm1ATION OF LONG- LIVED GAS SPECIES IN HYDROGEN THYRATRONS Martin Gundersen and Shekhar Guha Departments of Electrical Engineering and...area is inadequate. 2) Further study should make it possible to determine precisely the role of long- lived electronic states in thyratron recovery...3 sec. The 2s state of the hydrogen atom is also long- lived (Table I). Its formation is indicated by a strong Balmer emission. DISCUSSION The

  5. The elastic wave velocity response of methane gas hydrate formation in vertical gas migration systems

    NASA Astrophysics Data System (ADS)

    Bu, Q. T.; Hu, G. W.; Ye, Y. G.; Liu, C. L.; Li, C. F.; Best, A. I.; Wang, J. S.

    2017-06-01

    Knowledge of the elastic wave velocities of hydrate-bearing sediments is important for geophysical exploration and resource evaluation. Methane gas migration processes play an important role in geological hydrate accumulation systems, whether on the seafloor or in terrestrial permafrost regions, and their impact on elastic wave velocities in sediments needs further study. Hence, a high-pressure laboratory apparatus was developed to simulate natural continuous vertical migration of methane gas through sediments. Hydrate saturation (S h) and ultrasonic P- and S-wave velocities (V p and V s) were measured synchronously by time domain reflectometry (TDR) and by ultrasonic transmission methods respectively during gas hydrate formation in sediments. The results were compared to previously published laboratory data obtained in a static closed system. This indicated that the velocities of hydrate-bearing sediments in vertical gas migration systems are slightly lower than those in closed systems during hydrate formation. While velocities increase at a constant rate with hydrate saturation in the closed system, P-wave velocities show a fast-slow-fast variation with increasing hydrate saturation in the vertical gas migration system. The observed velocities are well described by an effective-medium velocity model, from which changing hydrate morphology was inferred to cause the fast-slow-fast velocity response in the gas migration system. Hydrate forms firstly at the grain contacts as cement, then grows within the pore space (floating), then finally grows into contact with the pore walls again. We conclude that hydrate morphology is the key factor that influences the elastic wave velocity response of methane gas hydrate formation in vertical gas migration systems.

  6. Low nanopore connectivity limits gas production in Barnett formation

    NASA Astrophysics Data System (ADS)

    Hu, Qinhong; Ewing, Robert P.; Rowe, Harold D.

    2015-12-01

    Gas-producing wells in the Barnett Formation show a steep decline from initial production rates, even within the first year, and only 12-30% of the estimated gas in place is recovered. The underlying causes of these production constraints are not well understood. The rate-limiting step in gas production is likely diffusive transport from matrix storage to the stimulated fracture network. Transport through a porous material such as shale is controlled by both geometry (e.g., pore size distribution) and topology (e.g., pore connectivity). Through an integrated experimental and theoretical approach, this work finds that the Barnett Formation has sparsely connected pores. Evidence of low pore connectivity includes the sparse and heterogeneous presence of trace levels of diffusing solutes beyond a few millimeters from a sample edge, the anomalous behavior of spontaneous water imbibition, the steep decline in edge-accessible porosity observed in tracer concentrations following vacuum saturation, the low (about 0.2-0.4% by volume) level presence of Wood's metal alloy when injected at 600 MPa pressure, and high tortuosity from mercury injection capillary pressure. Results are consistent with an interpretation of pore connectivity based on percolation theory. Low pore connectivity of shale matrix limits its mass transfer interaction with the stimulated fracture network from hydraulic fracturing and serves as an important underlying cause for steep declines in gas production rates and a low overall recovery rate.

  7. Spontaneous spinal epidural abscess.

    PubMed

    Ellanti, P; Morris, S

    2011-10-01

    Spinal epidural abscess is an uncommon entity, the frequency of which is increasing. They occur spontaneously or as a complication of intervention. The classical triad of fever, back pain and neurological symptoms are not always present. High index of suspicion is key to diagnosis. Any delay in diagnosis and treatment can have significant neurological consequences. We present the case of a previously well man with a one month history of back pain resulting from an epidural abscess.

  8. Central corneal abscess.

    PubMed

    van Bijsterveld, O P

    1976-05-01

    Central corneal abscess developed in the experimental animal after inoculation of biologically active staphylococcal strains in a paracentral epithelial lesion of the cornea. These abscesses did not ulcerate, developed only with high inocula, occurred more frequently in immunized rabbits. A serpiginous type of ulceration did not develop at the site of the initial epithelial lesion nor at any other place in the cornea. Histologically, the lesions consisted of densely packed polymorphonuclear leukocytes between the corneal lamellae.

  9. Aspergillus spinal epidural abscess

    SciTech Connect

    Byrd, B.F. III; Weiner, M.H.; McGee, Z.A.

    1982-12-17

    A spinal epidural abscess developed in a renal transplant recipient; results of a serum radioimmunoassay for Aspergillus antigen were positive. Laminectomy disclosed an abscess of the L4-5 interspace and L-5 vertebral body that contained hyphal forms and from which Aspergillus species was cultured. Serum Aspergillus antigen radioimmunoassay may be a valuable, specific early diagnostic test when systemic aspergillosis is a consideration in an immunosuppressed host.

  10. [Acute periproctal abscesses].

    PubMed

    Slauf, P; Antoš, F; Marx, J

    2014-04-01

    Periproctal inflammations related to the anus are characterized by the rapid spread of the infection to the surrounding tissue, which is determined by the anatomical characteristics and infectious agents. Inflammation, which starts as a phlegmon, quickly forms boundaries and an abscess develops in most cases. Up to 80-90% of anorectal abscesses develop according to the crypto-glandular theory on the basis of infection of the anal glands, spilling into the Morgagni crypts in the anal canal. Up to two-thirds of such abscesses are associated with the emergence of anorectal fistulas. Anorectal abscesses can be divided into marginal and subcutaneous perianal abscesses, submucosal, intersphincteric, ischiorectal and supralevator abscesses. Their diagnosis is based on thorough physical examination, sometimes also with the help of imaging methods such as computed tomography, magnetic resonance imaging and endoanal ultrasound. What is decisive for the successful treatment of anorectal abscessess is their early and adequate surgical drainage. Adjuvant antibiotic therapy is necessary only when the overall signs of sepsis are present and for patients with a comorbidity such as diabetes, valvular heart disease, or immunodeficiency.

  11. Relevance of trapping mechanisms in certain Michigan formation stray sandstone gas reservoirs to gas storage operations

    SciTech Connect

    Nowaczewski, S.F. )

    1994-08-01

    The Stray sandstones of the Michigan Formation were early exploration targets in the Michigan basin. Subsequent to primary production, some of these reservoirs were converted to gas storage. Many of the Stray fields were discovered in an underpressured state, whereas peak storage pressures often exceed native brine gradients. It can be demonstrated that the Stray sandstones exist in sheets and lenses throughout the central basin area, and that gas/water contacts exist in the gas reservoirs but behave volumetrically. Various indirect and direct evidence indicates that gas is trapped structurally by the antiformal geometry of the sandstone bodies, by probable fracture-controlled porosity, stratigraphically by the isolation of parts of the sand bodies due to depositional and diagenetic influences, and by structurally controlled stratigraphic relationships. The understanding of the trapping mechanisms allows successful high pressure-gradient gas storage and leads to understanding reservoir behavior, which should result in efficient storage development and operation. Additional direct and secondary benefits of understanding Stray sandstone structure and stratigraphy are demonstrated for gas storage operation nuisances such as water production, and for use of the Stray as a window to or a type for deeper formations.

  12. STAR FORMATION IN PARTIALLY GAS-DEPLETED SPIRAL GALAXIES

    SciTech Connect

    Rose, James A.; Miner, Jesse; Levy, Lorenza; Robertson, Paul E-mail: paul@astr.as.utexas.edu E-mail: lorenza.levy@yahoo.com

    2010-02-15

    Broadband B and R and H{alpha} images have been obtained with the 4.1 m SOAR telescope atop Cerro Pachon, Chile, for 29 spiral galaxies in the Pegasus I galaxy cluster and for 18 spirals in non-cluster environments. Pegasus I is a spiral-rich cluster with a low-density intracluster medium and a low galaxy velocity dispersion. When combined with neutral hydrogen (H I) data obtained with the Arecibo 305 m radio telescope, acquired by Levy et al. (2007) and by Springob et al. (2005b), we study the star formation rates in disk galaxies as a function of their H I deficiency. To quantify H I deficiency, we use the usual logarithmic deficiency parameter, DEF. The specific star formation rate (SSFR) is quantified by the logarithmic flux ratio of H{alpha} flux to R-band flux, and thus roughly characterizes the logarithmic SFR per unit stellar mass. We find a clear correlation between the global SFR per unit stellar mass and DEF, such that the SFR is lower in more H I-deficient galaxies. This correlation appears to extend from the most gas-rich to the most gas-poor galaxies. We also find a correlation between the central SFR per unit mass relative to the global values, in the sense that the more H I-deficient galaxies have a higher central SFR per unit mass relative to their global SFR values than do gas-rich galaxies. In fact, approximately half of the H I-depleted galaxies have highly elevated SSFRs in their central regions, indicative of a transient evolutionary state. In addition, we find a correlation between gas depletion and the size of the H{alpha} disk (relative to the R-band disk); H I-poor galaxies have truncated disks. Moreover, aside from the elevated central SSFR in many gas-poor spirals, the SSFR is otherwise lower in the H{alpha} disks of gas-poor galaxies than in gas-rich spirals. Thus, both disk truncation and lowered SSFR levels within the star-forming part of the disks (aside from the enhanced nuclear SSFR) correlate with H I deficiency, and both

  13. Formation of buffer-gas-trap based positron beams

    SciTech Connect

    Natisin, M. R. Danielson, J. R. Surko, C. M.

    2015-03-15

    Presented here are experimental measurements, analytic expressions, and simulation results for pulsed, magnetically guided positron beams formed using a Penning-Malmberg style buffer gas trap. In the relevant limit, particle motion can be separated into motion along the magnetic field and gyro-motion in the plane perpendicular to the field. Analytic expressions are developed which describe the evolution of the beam energy distributions, both parallel and perpendicular to the magnetic field, as the beam propagates through regions of varying magnetic field. Simulations of the beam formation process are presented, with the parameters chosen to accurately replicate experimental conditions. The initial conditions and ejection parameters are varied systematically in both experiment and simulation, allowing the relevant processes involved in beam formation to be explored. These studies provide new insights into the underlying physics, including significant adiabatic cooling, due to the time-dependent beam-formation potential. Methods to improve the beam energy and temporal resolution are discussed.

  14. Rectus sheath abscess after laparoscopic appendicectomy

    PubMed Central

    Golash, Vishwanath

    2007-01-01

    Port site wound infection, abdominal wall hematoma and intraabdominal abscess formation has been reported after laparoscopic appendicectomy. We describe here a rectus sheath abscess which occurred three weeks after the laparoscopic appendicectomy. It was most likely the result of secondary infection of the rectus sheath hematoma due to bleeding into the rectus sheath from damage to the inferior epigastric arteries or a direct tear of the rectus muscle. As far as we are aware this complication has not been reported after laparoscopic appendicectomy. PMID:21124654

  15. Star formation in semi-analytic galaxy formation models with multiphase gas

    NASA Astrophysics Data System (ADS)

    Somerville, Rachel S.; Popping, Gergö; Trager, Scott C.

    2015-11-01

    We implement physically motivated recipes for partitioning cold gas into different phases (atomic, molecular, and ionized) in galaxies within semi-analytic models of galaxy formation based on cosmological merger trees. We then model the conversion of molecular gas into stars using empirical recipes motivated by recent observations. We explore the impact of these new recipes on the evolution of fundamental galaxy properties such as stellar mass, star formation rate (SFR), and gas and stellar phase metallicity. We present predictions for stellar mass functions, stellar mass versus SFR relations, and cold gas phase and stellar mass-metallicity relations for our fiducial models, from redshift z ˜ 6 to the present day. In addition we present predictions for the global SFR, mass assembly history, and cosmic enrichment history. We find that the predicted stellar properties of galaxies (stellar mass, SFR, metallicity) are remarkably insensitive to the details of the recipes used for partitioning gas into H I and H2. We see significant sensitivity to the recipes for H2 formation only in very low mass haloes (M_h ≲ 10^{10.5} M_{⊙}), which host galaxies with stellar masses m_* ≲ 10^8 M_{⊙}. The properties of low-mass galaxies are also quite insensitive to the details of the recipe used for converting H2 into stars, while the formation epoch of massive galaxies does depend on this significantly. We argue that this behaviour can be interpreted within the framework of a simple equilibrium model for galaxy evolution, in which the conversion of cold gas into stars is balanced on average by inflows and outflows.

  16. Tongue abscess induced by embedded remnant fishbone.

    PubMed

    Chen, Pai-L; Chiang, C-W; Shiao, C-C

    2015-12-01

    The authors reported a 56-year-old man with progressive pain over left bottom of oral cavity involving tongue for 3 days. He had a puncture history of tongue by fishbone, which was immediately removed 3 weeks ago. The subsequent contrast-enhanced computed tomography scan of neck disclosed an abscess formation with a faint linear radiopaque material inside, consisting with remnant fishbone retention. The patient was treated conservatively with intravenous antibiotics, followed by an uneventful course during subsequent follow-up for more than 9 months until now. Tongue abscess is a rare but potentially life threatening clinical entity. Foreign body puncture-related tongue abscess should be listed as a differential diagnosis in cases with acute tongue swelling.

  17. Tongue abscess induced by embedded remnant fishbone.

    PubMed

    Chen, Pai-Lien; Chiang, Ching-Wen; Shiao, Chih-Chung

    2015-07-22

    The authors reported a 56-year-old man with progressive pain over left bottom of oral cavity involving tongue for 3 days. He had a puncture history of tongue by fishbone, which was immediately removed 3 weeks ago. The subsequent contrast-enhanced computed tomography scan of neck disclosed an abscess formation with a faint linear radiopaque material inside, consisting with remnant fishbone retention. The patient was treated conservatively with intravenous antibiotics, followed by an uneventful course during subsequent follow-up for more than 9 months until now. Tongue abscess is a rare but potentially life threatening clinical entity. Foreign body puncture-related tongue abscess should be listed as a differential diagnosis in cases with acute tongue swelling.

  18. Surfactant process for promoting gas hydrate formation and application of the same

    DOEpatents

    Rogers, Rudy E.; Zhong, Yu

    2002-01-01

    This invention relates to a method of storing gas using gas hydrates comprising forming gas hydrates in the presence of a water-surfactant solution that comprises water and surfactant. The addition of minor amounts of surfactant increases the gas hydrate formation rate, increases packing density of the solid hydrate mass and simplifies the formation-storage-decomposition process of gas hydrates. The minor amounts of surfactant also enhance the potential of gas hydrates for industrial storage applications.

  19. Efficiency of Natural Gas Flares Associated with Shale Formation Wells

    NASA Astrophysics Data System (ADS)

    Stirm, B.; Caulton, D.; Shepson, P.; Cambaliza, M. L.; Mccabe, D. C.; Baum, E.

    2012-12-01

    Hydraulic fracturing has increased access and economic viability of shale oil reserves. Currently the Bakken Oil field in North Dakota is experiencing a rapid increase in the drilling of shale oil wells. However, this process typically results in the simultaneous release of natural gas. Low natural gas prices and the lack of local gas pipeline infrastructure have decreased the incentive for companies to capture this natural gas, with many opting to vent or flare the natural gas instead. The impact of these operations on greenhouse gas emissions has not been well characterized. An undocumented variable of interest is the destruction efficiency of methane in active oil field flares. In situ measurements of flare efficiency are difficult to obtain because of the inaccessibility of the flares. In June of 2012 we conducted flights over shale oil wells and flares in the Bakken Formation near Williston, ND using Purdue University's Airborne Laboratory for Atmospheric Research (ALAR) which is equipped with a 0.5 Hz Picarro CO2/CH4/H2O analyzer and a Best Air Turbulence (BAT) probe that measures the wind vectors. In addition, one flare in the Marcellus Formation near Washington, PA was also sampled. Flare signals were identified based on the enhancements of CO2 above the ambient background signal and the corresponding colocated CH4 concentration. Enhancements were isolated by subtracting the background concentrations of CO2 and CH4 to obtain delta CO2 and delta CH4 values. Emission factors to be reported are obtained as the ratio delta CH4 divided by delta CO2. We will report first in situ measurements of natural gas flare efficiency. We observed a variety of meteorological conditions with winds ranging from 4 to 15 m/s and will report on the relationship between wind speed and flare efficiency. We observed very high flare efficiency even under strong winds (at least 99.8% CO2 for all flares). During flare sampling, we observed a number of CH4 enhancements that were

  20. Brain abscess potentially secondary to odontogenic infection: case report.

    PubMed

    Yang, Joseph; Liu, Stanley Y; Hossaini-Zadeh, Mehran; Pogrel, M Anthony

    2014-02-01

    Odontogenic infections are rarely implicated in the causes of brain abscess formation. As such, there are very few reports of brain abscesses secondary to odontogenic infections in the literature. This is due partly to the relative rarity of brain abscesses but also to the difficulty in matching the causative organisms of a brain abscess to an odontogenic source. The authors report a case of a 50-year-old woman whose brain abscess may potentially have been secondary to an odontogenic infection. The patient's early diagnosis, supported by imaging and microbiologic assessment, along with early minicraniotomy and extraction of infected dentition followed by a course of cephalosporins and metronidazole, contributed to a successful outcome. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Gaseous sodium sulfate formation in flames and flowing gas environments

    NASA Technical Reports Server (NTRS)

    Stearns, C. A.; Miller, R. A.; Kohl, F. J.; Fryburg, G. C.

    1977-01-01

    Formation of Na2SO4(g) in flames and hot flowing gas systems was studied by high pressure, free-jet expansion, modulated molecular beam mass spectrometric sampling. Fuel-lean CH4-O2 flames doped with SO2, H2O and NaCl yielded the gaseous Na2SO4 molecule in residence times of less than one millisecond. Intermediate species NaSO2(g) and NaSO3(g) were also observed and measured. Composition profiles were obtained for all reaction products. Nonflame flowing gas experiments showed that Na2SO4 and NaSO3 gaseous molecules were formed at 1140 C in mixtures of O2, H2O(g), SO2 and NaCl(g). Experimental results are compared with calculated equilibrium thermodynamic predictions.

  2. Extradural frontal abscess complicating nasal septal abscess in a child.

    PubMed

    Thomson, C J; Berkowitz, R G

    1998-10-02

    Nasal septal abscess (NSA) is an uncommon sequel to minor nasal trauma. Abscess extension beyond the nasal cavity is rarely documented. A case of a 10-year-old boy who presented with a NSA associated with a large extradural frontal abscess is presented and indications for CT scanning in the workup of pediatric patients with NSA is discussed.

  3. Formation of Prestellar Cores via Non-Isothermal Gas Fragmentation

    NASA Astrophysics Data System (ADS)

    Anathpindika, S.

    2015-02-01

    Sheet-like clouds are common in turbulent gas and perhaps form via collisions between turbulent gas flows. Having examined the evolution of an isothermal shocked slab in an earlier contribution, in this work we follow the evolution of a sheet-like cloud confined by (thermal) pressure and gas in it is allowed to cool. The extant purpose of this endeavour is to study the early phases of core-formation. The observed evolution of this cloud supports the conjecture that molecular clouds themselves are three-phase media (comprising viz. a stable cold and warm medium, and a third thermally unstable medium), though it appears, clouds may evolve in this manner irrespective of whether they are gravitationally bound. We report, this sheet fragments initially due to the growth of the thermal instability (TI) and some fragments are elongated, filament-like. Subsequently, relatively large fragments become gravitationally unstable and sub-fragment into smaller cores. The formation of cores appears to be a three stage process: first, growth of the TI leads to rapid fragmentation of the slab; second, relatively small fragments acquire mass via gas-accretion and/or merger and third, sufficiently massive fragments become susceptible to the gravitational instability and sub-fragment to form smaller cores. We investigate typical properties of clumps (and smaller cores) resulting from this fragmentation process. Findings of this work support the suggestion that the weak velocity field usually observed in dense clumps and smaller cores is likely seeded by the growth of dynamic instabilities. Simulations were performed using the smooth particle hydrodynamics algorithm.

  4. GAS, STARS, AND STAR FORMATION IN ALFALFA DWARF GALAXIES

    SciTech Connect

    Huang Shan; Haynes, Martha P.; Giovanelli, Riccardo; Brinchmann, Jarle; Stierwalt, Sabrina; Neff, Susan G. E-mail: haynes@astro.cornell.edu E-mail: jarle@strw.leidenuniv.nl E-mail: susan.g.neff@nasa.gov

    2012-06-15

    We examine the global properties of the stellar and H I components of 229 low H I mass dwarf galaxies extracted from the ALFALFA survey, including a complete sample of 176 galaxies with H I masses <10{sup 7.7} M{sub Sun} and H I line widths <80 km s{sup -1}. Sloan Digital Sky Survey (SDSS) data are combined with photometric properties derived from Galaxy Evolution Explorer to derive stellar masses (M{sub *}) and star formation rates (SFRs) by fitting their UV-optical spectral energy distributions (SEDs). In optical images, many of the ALFALFA dwarfs are faint and of low surface brightness; only 56% of those within the SDSS footprint have a counterpart in the SDSS spectroscopic survey. A large fraction of the dwarfs have high specific star formation rates (SSFRs), and estimates of their SFRs and M{sub *} obtained by SED fitting are systematically smaller than ones derived via standard formulae assuming a constant SFR. The increased dispersion of the SSFR distribution at M{sub *} {approx}< 10{sup 8} M{sub Sun} is driven by a set of dwarf galaxies that have low gas fractions and SSFRs; some of these are dE/dSphs in the Virgo Cluster. The imposition of an upper H I mass limit yields the selection of a sample with lower gas fractions for their M{sub *} than found for the overall ALFALFA population. Many of the ALFALFA dwarfs, particularly the Virgo members, have H I depletion timescales shorter than a Hubble time. An examination of the dwarf galaxies within the full ALFALFA population in the context of global star formation (SF) laws is consistent with the general assumptions that gas-rich galaxies have lower SF efficiencies than do optically selected populations and that H I disks are more extended than stellar ones.

  5. Gas, Stars, and Star Formation in Alfalfa Dwarf Galaxies

    NASA Technical Reports Server (NTRS)

    Huang, Shan; Haynes, Martha P.; Giovanelli, Riccardo; Brinchmann, Jarle; Stierwalt, Sabrina; Neff, Susan G.

    2012-01-01

    We examine the global properties of the stellar and Hi components of 229 low H i mass dwarf galaxies extracted from the ALFALFA survey, including a complete sample of 176 galaxies with H i masses <10(sup 7.7) solar mass and Hi line widths <80 kilometers per second. Sloan Digital Sky Survey (SDSS) data are combined with photometric properties derived from Galaxy Evolution Explorer to derive stellar masses (M*) and star formation rates (SFRs) by fitting their UV-optical spectral energy distributions (SEDs). In optical images, many of the ALFALFA dwarfs are faint and of low surface brightness; only 56% of those within the SDSS footprint have a counterpart in the SDSS spectroscopic survey. A large fraction of the dwarfs have high specific star formation rates (SSFRs), and estimates of their SFRs and M* obtained by SED fitting are systematically smaller than ones derived via standard formulae assuming a constant SFR. The increased dispersion of the SSFR distribution at M* approximately less than10(exp 8)M(sub 0) is driven by a set of dwarf galaxies that have low gas fractions and SSFRs; some of these are dE/dSphs in the Virgo Cluster. The imposition of an upper Hi mass limit yields the selection of a sample with lower gas fractions for their M* than found for the overall ALFALFA population. Many of the ALFALFA dwarfs, particularly the Virgo members, have H i depletion timescales shorter than a Hubble time. An examination of the dwarf galaxies within the full ALFALFA population in the context of global star formation (SF) laws is consistent with the general assumptions that gas-rich galaxies have lower SF efficiencies than do optically selected populations and that Hi disks are more extended than stellar ones.

  6. Development of Glioblastoma after Treatment of Brain Abscess.

    PubMed

    Matsumoto, Hiroaki; Minami, Hiroaki; Tominaga, Shogo; Yoshida, Yasuhisa

    2016-04-01

    Abscess formation within a glioblastoma has been reported rarely. In the few reported cases, after aspiration to treat a presumed abscess, lesions recurred over a short period and, consequently, glioblastoma was recognized. We present a case of a glioblastoma that developed 1.5 years after successful treatment of a brain abscess. A latency of 1.5 years before symptom development seems overly long, even if the glioblastoma was present at the time of the initial brain abscess. Hence, we consider this a possible de novo glioblastoma arising from glial scar tissue. We also discuss possible mechanisms underlying malignant transformation. A 78-year-old man was admitted to our hospital with progressive gait disturbance caused by a brain abscess. Aspiration of the cyst and systematic antibiotic therapy cured the abscess. However, 1.5 years later, the patient presented to our hospital with generalized convulsions due to recurrence of the cystic lesion. He underwent craniotomy for removal of the cystic lesion, which was found to be a glioblastoma rather than a recurrent brain abscess. Glial scar tissue was detected in the cyst wall. Development of glioblastoma after treatment of a brain abscess is rare; the pathogenesis is open to speculation. Based on the clinical course, the pathologic findings, and comparison with previous reports, de novo glioblastoma arising from glial scar tissue may be the most likely explanation of the current case. If so, to our knowledge, this is the first report of this condition. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Group A streptococcal brain abscess: a case report and a review of the literature since 1988.

    PubMed

    Hayashi, Anri; Takano, Tomoyuki; Suzuki, Atsushi; Narumiya, Seiro

    2011-07-01

    Brain abscesses caused by group A Streptococcus (GAS) are rare infectious diseases. In this report we present a case of brain abscess due to GAS infection occurring after milk tooth extraction in a healthy child. A literature review of previously reported cases is presented.

  8. Acoustic Investigations of Gas and Gas Hydrate Formations, Offshore Southwestern Black Sea*

    NASA Astrophysics Data System (ADS)

    Kucuk, H. M.; Dondurur, D.; Ozel, O.; Atgin, O.; Sinayuc, C.; Merey, S.; Parlaktuna, M.; Cifci, G.

    2015-12-01

    The Black Sea is a large intercontinental back-arc basin with relatively high sedimentation rate. The basin was formed as two different sub-basins divided by Mid-Black Sea Ridge. The ridge is completely buried today and the Black Sea became a single basin in the early Miocene that is currently anoxic. Recent acoustic investigations in the Black Sea indicate potential for gas hydrate formation and gas venting. A total of 2500 km multichannel seismic, Chirp sub-bottom profiler and multibeam bathymetry data were collected during three different expeditions in 2010 and 2012 along the southwestern margin of the Black Sea. Box core sediment samples were collected for gas cromatography analysis. Wide spread BSRs and multiple BSRs are observed in the seismic profiles and may be categorized into two different types: cross-cutting BSRs (transecting sedimentary strata) and amplitude BSRs (enhanced reflections). Both types mimic the seabed reflection with polarity reversal. Some undulations of the BSR are observed along seismic profiles probably caused by local pressure and/or temperature changes. Shallow gas sources and chimney vents are clearly indicated by bright reflection anomalies in the seismic data. Gas cromatography results indicate the presence of methane and various components of heavy hydrocarbons, including Hexane. These observations suggest that the gas forming hydrate in the southwestern Black Sea may originate from deeper thermogenic hydrocarbon sources. * This study is supported by 2214-A programme of The Scientific and Technological Research Council of Turkey (TÜBITAK).

  9. Anatomy of a Spiral Arm: Gas, Dust and Star Formation

    NASA Astrophysics Data System (ADS)

    Schinnerer, Eva; Meidt, Sharon; Pety, Jerome; Leroy, Adam; Hughes, Annie; Colombo, Dario

    2015-08-01

    Spiral arms can be easily depicted in disk galaxies from the numerous young stars associated with them. However, it is on a fundamental level not clear where, how and when star formation starts relative to the spiral arm. We address these questions by utilizing high 1-3'' resolution observation of the total and dense molecular gas in a spiral arm segment of the nearby grand-design spiral galaxy M51 from PAWS (PdBI Arcsecond Whirlpool Survey) in combination with observations of young stars, HII regions and dust emission. We build a complete picture of the onset, progression and impact of star formation for this segment and discuss this picture in light of theoretical expectations.

  10. Anaerobic brain abscess

    PubMed Central

    Sudhaharan, Sukanya; Chavali, Padmasri

    2016-01-01

    Background and Objectives: Brain abscess remains a potentially fatal central nervous system (CNS) disease, especially in developing countries. Anaerobic abscess is difficult to diagnose because of cumbersome procedures associated with the isolation of anaerobes. Materials and Methods: This is a hospital-based retrospective microbiological analysis of 430 brain abscess materials (purulent aspirates and/or tissue), for anaerobic organisms, that were received between 1987–2014, by the Microbiology Laboratory in our Institute. Results: Culture showed growth of bacteria 116/430 (27%) of the cases of which anaerobes were isolated in 48/116 (41.1%) of the cases. Peptostreptococcus (51.4 %), was the predominant organism isolated in four cases followed by Bacteroides and Peptococcus species. Conclusion: Early diagnosis and detection of these organisms would help in the appropriate management of these patients. PMID:27307977

  11. Gas geochemistry characteristic of shale gas in Longmaxi Formation, SE Sichuan Basin, China

    NASA Astrophysics Data System (ADS)

    Cao, Chunhui; Du, Li; Li, Liwu; He, Jian; Li, Zhongping

    2017-01-01

    Shale gas samples collected from Lower Silurian Longmaxi Formation of Southern Sichuan Basin in Weiyuan were analysed for stable isotope composition of noble gases and molecular composition, stable carbon isotope composition of hydrocarbons. Results show these shale gases are of organic origin gas, and produced at high-over maturity stage. All the analysed hydrocarbon gases reveal complete inversed isotopic trends from methane to propane, and δ13C1, δ13C2 have obviously different between Weiyuan and Changning areas. CO2 was mainly generated during thermogenic processes of transformation of organic matter, although some gases can contain components from endogenic processes and from thermal destruction of carbonates. He and Ar are mainly product of α-decay of U and Th enriched in crustal materials. A small contribution of mantle origin He was found in the gas reservoirs. Continuous monitoring data indicate 3He/4He ratio didn’t change with the mining time.

  12. Cervical abscess and pharyngeal fistula in a horse.

    PubMed

    Scott, E A

    1975-04-15

    A weanling Quarter Horse filly developed ventral swelling of the lower cervical area after difficult passage of a stomach tube for deworming. Intermittent bilateral nasal discharge developed. Radiography revealed fluid and gas density dorsal to the trachea and esophagus. Surgical incision with drainage and debridement of the abscess and fistulous tract, facilitated by use of drains, led to complete recovery. Contrast medium injected after surgery demonstrated a communication between the abscess and the pharyngeal region.

  13. Splenic abscess with Clostridium novyi bacteraemia and sepsis.

    PubMed

    Vleminckx, W G; Diltoer, M W; Spapen, H D; Pierard, D; De Mey, J; Delvaux, G R; Huyghens, L P

    1997-03-01

    Splenic abscess is an uncommon entity and usually results in the death of the patient when left undiagnosed. A case is presented where bacteraemia with an anaerobic Gram-positive bacillus was associated with splenic abscess. Despite treatment with splenectomy and antibiotics the patient developed a multiple organ dysfunction syndrome (MODS) and died. Of particular interest was the isolation of Clostridium novyi type A from the blood in a patient without gas gangrene but with splenic suppuration.

  14. Spinal epidural abscess.

    PubMed

    Johnson, Katherine G

    2013-09-01

    Spinal epidural abscess is a rare bacterial infection located within the spinal canal. Early diagnosis and rapid treatment are important because of its potential to cause rapidly progressive spinal cord compression and irreversible paralysis. A staphylococcus bacterial infection is the cause in most cases. Treatment includes antibiotics and possible surgical drainage of the abscess. A favorable neurologic outcome correlates with the severity and duration of neurologic deficits before surgery and the timeliness of the chosen intervention. It is important for the critical care nurse to monitor the patient's neurologic status and provide appropriate interventions.

  15. Intracerebral abscess with dissecting pneumocephalus caused by a gas-producing gram-positive rod following craniotomy for glioblastoma multiforme resection.

    PubMed

    Sarkiss, Christopher A; Soleymani, Teo; Caplan, Justin M; Dorsi, Michael J; Huang, Judy

    2013-11-01

    Propionibacterium acnes (P. acnes), an indolent and slow-growing anaerobic gram-positive bacterium, has largely been known as a commensal organism of the normal skin flora. However, P. acnes is increasingly being recognized as the causative infectious organism complicating craniotomies and shunt insertions. To our knowledge, we present the first reported patient with an intracerebral abscess with dissecting pneumocephalus caused by P. acnes. A 58-year-old woman who was immunocompetent presented 3 weeks after a craniotomy for resection of a glioblastoma multiforme with worsening mental status, lethargy and left hemiparesis. Head CT scans and MRI demonstrated significant vasogenic edema and dissecting pneumocephalus in the resection cavity. A craniotomy was performed and purulent material was found in the subdural space and resection cavity. Cultures were positive for P. acnes. She completed a full course of intravenous antibiotics appropriate for the organism. The infection was eradicated and the patient survived albeit with persistent deficits. This case illustrates the importance of considering an underlying intracerebral abscess in patients with worsening neurological function and pneumocephalus on imaging several weeks after surgery. Our review of the literature underscores the great importance in early recognition and treatment with both surgical debridement and antibiotic therapy in achieving optimal patient recovery.

  16. Plasma formation inside deformed gas bubbles submerged in water

    NASA Astrophysics Data System (ADS)

    Sommers, Bradley; Foster, John

    2012-10-01

    Plasma formation in liquids produces highly reactive products that may be desirable for a variety of applications, including water purification and waste processing. The direct ignition of plasma in these environments, however, is limited by the large breakdown strength of liquids, which imposes severe voltage and energy requirements on the design of practical devices. One way to address this issue is by first igniting plasma in gas bubbles injected into the water. These bubbles provide an environment with higher reduced electric field (E/N) that is more suitable for plasma formation. If the same bubbles can be excited into strong distortions of their shape and volume, then it is possible to further alter E/N, both by field enhancement at the bubble's highly distorted dielectric interface (via E) and by fluctuations in its internal gas pressure (via N). This principle is investigated by trapping a single bubble at the node of a 26.4 kHz underwater acoustic field and driving it into violent oscillations using an A.C electric field. A third high voltage needle is placed nearby and used to ignite plasma in the bubble at various points during its oscillation. The bubble response is captured using a high speed camera capable of up to 30,000 frames per second.

  17. Project ARGO: Gas phase formation in simulated microgravity

    NASA Technical Reports Server (NTRS)

    Powell, Michael R.; Waligora, James M.; Norfleet, William T.; Kumar, K. Vasantha

    1993-01-01

    The ARGO study investigated the reduced incidence of joint pain decompression sickness (DCS) encountered in microgravity as compared with an expected incidence of joint pain DCS experienced by test subjects in Earth-based laboratories (unit gravity) with similar protocols. Individuals who are decompressed from saturated conditions usually acquire joint pain DCS in the lower extremities. Our hypothesis is that the incidence of joint pain DCS can be limited by a significant reduction in the tissue gas micronuclei formed by stress-assisted nucleation. Reductions in dynamic and kinetic stresses in vivo are linked to hypokinetic and adynamic conditions of individuals in zero g. We employed the Doppler ultrasound bubble detection technique in simulated microgravity studies to determine quantitatively the degree of gas phase formation in the upper and lower extremities of test subjects during decompression. We found no evidence of right-to-left shunting through pulmonary vasculature. The volume of gas bubble following decompression was examined and compared with the number following saline contrast injection. From this, we predict a reduced incidence of DCS on orbit, although the incidence of predicted mild DCS still remains larger than that encountered on orbit.

  18. THE FORMATION MECHANISM OF GAS GIANTS ON WIDE ORBITS

    SciTech Connect

    Dodson-Robinson, Sarah E.; Veras, Dimitri; Ford, Eric B.; Beichman, C. A.

    2009-12-10

    The recent discoveries of massive planets on ultra-wide orbits of HR 8799 and Fomalhaut present a new challenge for planet formation theorists. Our goal is to figure out which of three giant planet formation mechanisms-core accretion (with or without migration), scattering from the inner disk, or gravitational instability-could be responsible for Fomalhaut b, HR 8799 b, c and d, and similar planets discovered in the future. This paper presents the results of numerical experiments comparing the long-period planet formation efficiency of each possible mechanism in model A star, G star, and M star disks. First, a simple core accretion simulation shows that planet cores forming beyond 35 AU cannot reach critical mass, even under the most favorable conditions one can construct. Second, a set of N-body simulations demonstrates that planet-planet scattering does not create stable, wide-orbit systems such as HR 8799. Finally, a linear stability analysis verifies previous work showing that global spiral instabilities naturally arise in high-mass disks. We conclude that massive gas giants on stable orbits with semimajor axes a approx> 35 AU form by gravitational instability in the disk. We recommend that observers examine the planet detection rate as a function of stellar age, controlling for the planets' dimming with time. Any age trend would indicate that planets on wide orbits are transient relics of scattering from the inner disk. If planet detection rate is found to be independent of stellar age, it would confirm our prediction that gravitational instability is the dominant mode of producing detectable planets on wide orbits. We also predict that the occurrence ratio of long-period to short-period gas giants should be highest for M dwarfs due to the inefficiency of core accretion and the expected small fragment mass (approx10 M {sub Jup}) in their disks.

  19. Rapid Development of Brain Abscess Caused by Streptococcus Pyogenes Following Penetrating Skull Injury via the Ethmoidal Sinus and Lamina Cribrosa

    PubMed Central

    Aydin, Gerilmez; Cömert, Serhat; Altinors, Nur

    2010-01-01

    Objective Streptococcus pyogenes is a beta-hemolytic bacterium that belongs to Lancefield serogroup A, also known as group A streptococci (GAS). There have been five reported case in terms of PubMed-based search but no reported case of brain abscess caused by Streptococcus pyogenes as a result of penetrating skull injury. We present a patient who suffered from penetrating skull injury that resulted in a brain abscess caused by Streptococcus pyogenes. Methods The patient was a 12-year-old boy who fell down from his bicycle while cycling and ran into a tree. A wooden stick penetrated his skin below the right lower eyelid and advanced to the cranium. He lost consciousness on the fifth day of the incident and his body temperature was measured as 40℃. While being admitted to our hospital, a cranial computed tomography revealed a frontal cystic mass with a perilesional hypodense zone of edema. There was no capsule formation around the lesion after intravenous contrast injection. Paranasal CT showed a bone defect located between the ethmoidal sinus and lamina cribrosa. Results Bifrontal craniotomy was performed. The abscess located at the left frontal lobe was drained and the bone defect was repaired. Conclusion Any penetrating lesion showing a connection between the lamina cribrosa and ethmoidal sinus may result in brain abscess caused by Streptococcus pyogenes. These patients should be treated urgently to repair the defect and drain the abscess with appropriate antibiotic therapy started due to the fulminant course of the brain abscess caused by this microorganism. PMID:20717517

  20. Percutaneous Abscess Drainage

    MedlinePlus

    ... the local anesthetic is injected. Most of the sensation is at the skin incision site which is numbed using local anesthetic. ... open surgical drainage. Risks Any procedure where the skin is penetrated ... organ may be damaged by percutaneous abscess drainage. Occasionally ...

  1. Pyogenic liver abscess

    PubMed Central

    Webb, Gwilym James; Chapman, Thomas Patrick; Cadman, Philip John; Gorard, David Angelo

    2014-01-01

    Pyogenic liver abscess has a variable clinical presentation. Its management requires input from several disciplines and is often coordinated by a gastroenterologist. This review examines demographics, clinical presentation, aetiology, diagnosis and prognosis; a suggested management approach, including antibiotic selection, radiological intervention and indications for surgery, is offered from a physician's perspective. PMID:28839753

  2. MOLECULAR GAS AND STAR FORMATION IN NEARBY DISK GALAXIES

    SciTech Connect

    Leroy, Adam K.; Munoz-Mateos, Juan-Carlos; Walter, Fabian; Sandstrom, Karin; Meidt, Sharon; Rix, Hans-Walter; Schinnerer, Eva; Schruba, Andreas; Bigiel, Frank; Bolatto, Alberto; Brinks, Elias; De Blok, W. J. G.; Rosolowsky, Erik; Schuster, Karl-Friedrich; Usero, Antonio

    2013-08-01

    We compare molecular gas traced by {sup 12}CO (2-1) maps from the HERACLES survey, with tracers of the recent star formation rate (SFR) across 30 nearby disk galaxies. We demonstrate a first-order linear correspondence between {Sigma}{sub mol} and {Sigma}{sub SFR} but also find important second-order systematic variations in the apparent molecular gas depletion time, {tau}{sub dep}{sup mol}={Sigma}{sub mol}/{Sigma}{sub SFR}. At the 1 kpc common resolution of HERACLES, CO emission correlates closely with many tracers of the recent SFR. Weighting each line of sight equally, using a fixed {alpha}{sub CO} equivalent to the Milky Way value, our data yield a molecular gas depletion time, {tau}{sub dep}{sup mol}={Sigma}{sub mol}/{Sigma}{sub SFR}{approx}2.2 Gyr with 0.3 dex 1{sigma} scatter, in very good agreement with recent literature data. We apply a forward-modeling approach to constrain the power-law index, N, that relates the SFR surface density and the molecular gas surface density, {Sigma}{sub SFR}{proportional_to}{Sigma}{sub mol}{sup N}. We find N = 1 {+-} 0.15 for our full data set with some scatter from galaxy to galaxy. This also agrees with recent work, but we caution that a power-law treatment oversimplifies the topic given that we observe correlations between {tau}{sub dep}{sup mol} and other local and global quantities. The strongest of these are a decreased {tau}{sub dep}{sup mol} in low-mass, low-metallicity galaxies and a correlation of the kpc-scale {tau}{sub dep}{sup mol} with dust-to-gas ratio, D/G. These correlations can be explained by a CO-to-H{sub 2} conversion factor ({alpha}{sub CO}) that depends on dust shielding, and thus D/G, in the theoretically expected way. This is not a unique interpretation, but external evidence of conversion factor variations makes this the most conservative explanation of the strongest observed {tau}{sub dep}{sup mol} trends. After applying a D/G-dependent {alpha}{sub CO}, some weak correlations between {tau}{sub dep

  3. Gas, Stars, and Star Formation in ALFALFA Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Huang, Shan; Haynes, Martha P.; Giovanelli, Riccardo; Brinchmann, Jarle; Stierwalt, Sabrina; Neff, Susan G.

    2012-06-01

    We examine the global properties of the stellar and H I components of 229 low H I mass dwarf galaxies extracted from the ALFALFA survey, including a complete sample of 176 galaxies with H I masses <107.7 M ⊙ and H I line widths <80 km s-1. Sloan Digital Sky Survey (SDSS) data are combined with photometric properties derived from Galaxy Evolution Explorer to derive stellar masses (M *) and star formation rates (SFRs) by fitting their UV-optical spectral energy distributions (SEDs). In optical images, many of the ALFALFA dwarfs are faint and of low surface brightness; only 56% of those within the SDSS footprint have a counterpart in the SDSS spectroscopic survey. A large fraction of the dwarfs have high specific star formation rates (SSFRs), and estimates of their SFRs and M * obtained by SED fitting are systematically smaller than ones derived via standard formulae assuming a constant SFR. The increased dispersion of the SSFR distribution at M * <~ 108 M ⊙ is driven by a set of dwarf galaxies that have low gas fractions and SSFRs; some of these are dE/dSphs in the Virgo Cluster. The imposition of an upper H I mass limit yields the selection of a sample with lower gas fractions for their M * than found for the overall ALFALFA population. Many of the ALFALFA dwarfs, particularly the Virgo members, have H I depletion timescales shorter than a Hubble time. An examination of the dwarf galaxies within the full ALFALFA population in the context of global star formation (SF) laws is consistent with the general assumptions that gas-rich galaxies have lower SF efficiencies than do optically selected populations and that H I disks are more extended than stellar ones. Based on observations made with the Arecibo Observatory and the NASA Galaxy Evolution Explorer (GALEX). The Arecibo Observatory is operated by SRI International under a cooperative agreement with the National Science Foundation (AST-1100968), and in alliance with Ana G. Méndez-Universidad Metropolitana and

  4. Subperiosteal abscess in a child. Trueta's osteomyelitis hypothesis undermined?

    PubMed

    Weenders, S G M; Janssen, N E; Landman, G W D; van den Berg, F P

    2015-10-01

    Subperiosteal abscess formation is almost exclusively seen secondary to underlying hematogenous infected osteomyelitis or secondary as a result of a contagious focus. We present an unusual case of a 9-year-old girl with progressive ankle pain due to an isolated subperiosteal abscess of the distal fibula without concomitant osteomyelitis. The subperiosteal abscess was most likely caused by hematogenous spread to the periosteal region of the distal fibula located above the highly vascularized metaphysis. Remarkably, there were no signs of osteomyelitis on either MRI or during surgical inspection. She was successfully treated with debridement and antibiotic therapy. We hypothesize that subperiosteal abscess formation near the metaphysis originates in the periosteal region and not from outward extension from the sinusoidal veins in the intrametaphyseal area to the cortex and subperiosteal region.

  5. Molecule formation in quasar broad-line cloud gas

    NASA Technical Reports Server (NTRS)

    Kallman, T.; Lepp, S.; Giovannoni, P.

    1987-01-01

    Models for the broad-line emitting clouds of quasars typically assume that the clouds have column densities of at most 10 to the 23rd/sq cm. The consequences of relaxing this assumption are examined, and it is shown that: (1) at slightly larger column densities the gas may cool to about 1000 K as a result of molecule formation; (2) in much of the molecule-forming region the temperature may have either of two values, about 1000 K or 6000-8000 K; (3) the strengths of most observable optical lines, including C II semiforbidden 2326-A lines and Fe II lines, are unaffected by such large column densities; and (4) lines from low-ionization species such as Na I are readily formed at large column densities. Observations of such lines provide evidence for large cloud column densities.

  6. Human Exoproteome in Acute Apical Abscesses.

    PubMed

    Alfenas, Cristiane F; Mendes, Tiago A O; Ramos, Humberto J O; Bruckner, Fernanda P; Antunes, Henrique S; Rôças, Isabela N; Siqueira, José F; Provenzano, José C

    2017-09-01

    An acute apical abscess is a severe response of the host to massive invasion of the periapical tissues by bacteria from infected root canals. Although many studies have investigated the microbiota involved in the process, information on the host factors released during abscess formation is scarce. The purpose of this study was to describe the human exoproteome in samples from acute apical abscesses. Fourteen pus samples were obtained by aspiration from patients with an acute apical abscess. Samples were subjected to protein digestion, and the tryptic peptides were analyzed using a mass spectrometer and ion trap instrument. The human proteins identified in this analysis were classified into different functional categories. A total of 303 proteins were identified. Most of these proteins were involved in cellular and metabolic processes. Immune system proteins were also very frequent and included immunoglobulins, S100 proteins, complement proteins, and heat shock proteins. Polymorphonuclear neutrophil proteins were also commonly detected, including myeloperoxidases, defensins, elastases, and gelatinases. Iron-sequestering proteins including transferrin and lactoferrin/lactotransferrin were found in many samples. The human exoproteome included a wide variety of proteins related to cellular processes, metabolism, and immune response. Proteins involved in different mechanisms against infection, tissue damage, and protection against tissue damage were identified. Knowledge of the presence and function of these proteins using proteomics provides an insight into the complex host-pathogen relationship, the host antimicrobial strategies to fight infections, and the disease pathogenesis. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  7. Liver abscesses with venous extension - rare complication of a common problem.

    PubMed

    Lal, Hira; Thakral, Anuj; Sharma, Manohar Lal; Kumar, Tarun

    2014-12-01

    Considering the high incidence of amoebic and pyogenic liver abscess in the developing world, occurrence of inferior vena cava thrombosis secondary to liver abscess is a rare but life threatening complication. We report 4 such complicated cases of liver abscess(s). The first case involved a large caudate lobe abscess extending across middle hepatic vein into suprahepatic inferior vena cava (IVC). Development of a left hepatic artery pseudoaneurysm following attempted percutaneous aspiration highlights the difficulties encountered in percutaneous interventional management of caudate lobe abscesses. The second case involved multiple liver abscesses with large thrombus in the right ventricular cavity & right ventricular outflow tract. The patient developed cardiorespiratory arrest limiting any aggressive management options for the complex nature of illness. The third case had a large caudate lobe abscess with direct extension into Intrahepatic IVC while the fourth showed a segment 4 abscess with thrombosis of adjacent left hepatic vein. These cases highlight the fact that diagnosis of such life threatening complications of liver abscesses as hepatic vein & IVC thrombosis requires high clinical suspicion followed by targeted imaging. Image guided interventional therapy is a useful tool for management in cases of liver abscess. But, abscesses in precarious locations like caudate lobe are associated with higher risk of complications including pseudoaneurysm formation asking for a cautious approach to interventional therapy in such circumstances.

  8. Ruptured splenic abscess: a cause of pneumoperitoneum in a patient with AIDS.

    PubMed

    Ishigami, Kousei; Decker, Gerald T; Bolton-Smith, Jody A; Samuel, Isaac; Wilson, Scott R; Brown, Bruce P

    2003-12-01

    We encountered a case of pneumoperitoneum caused by a gas-forming splenic abscess in a patient with acquired immunodeficiency syndrome (AIDS). Plain abdominal films and computed tomography demonstrated a large amount of free air. Pneumoperitoneum was eventually shown to represent gas liberated from fermentation by gas-forming organisms within the splenic abscess. Gas-containing necrotic tissue from the ruptured spleen mimicked the spillage of feces from colon perforation. The authors emphasize that a ruptured abscess should be included in the differential diagnosis of acute abdomen in an immunocompromised patient.

  9. Planet Formation Signposts: Observability of Circumplanetary Disks via Gas Kinematics

    NASA Astrophysics Data System (ADS)

    Perez, Sebastian; Dunhill, A.; Casassus, S.; Roman, P.; Szulágyi, J.; Flores, C.; Marino, S.; Montesinos, M.

    2015-09-01

    The identification of ongoing planet formation requires the finest angular resolutions and deepest sensitivities in observations inspired by state-of-the-art numerical simulations. Hydrodynamic simulations of planet-disk interactions predict the formation of circumplanetary disks (CPDs) around accreting planetary cores. These CPDs have eluded unequivocal detection—their identification requires predictions in CPD tracers. In this work, we aim to assess the observability of embedded CPDs with the Atacama Large Millimeter/submillimeter Array (ALMA) as features imprinted in the gas kinematics. We use 3D smooth particle hydrodynamic simulations of CPDs around 1 and 5 {M}{Jup} planets at large stellocentric radii in locally isothermal and adiabatic disks. The simulations are then connected with 3D radiative transfer for predictions in CO isotopologues. Observability is assessed by corrupting with realistic long baseline phase noise extracted from the recent HL Tau ALMA data. We find that the presence of a CPD produces distinct signposts: (1) a compact emission separated in velocity from the overall circumstellar disk’s Keplerian pattern, (2) a strong impact on the velocity pattern when the Doppler-shifted line emission sweeps across the CPD location, and (3) a local increase in the velocity dispersion. We test our predictions with a simulation tailored for HD 100546—which has a reported protoplanet candidate. We find that the CPDs are detectable in all three signposts with ALMA Cycle 3 capabilities for both 1 and 5 {M}{Jup} protoplanets, when embedded in an isothermal disk.

  10. CT differentiation between tubo-ovarian and appendiceal origin of right lower quadrant abscess: CT, clinical, and laboratory correlation.

    PubMed

    Hiller, Nurith; Fux, Tal; Finkelstein, Anna; Mezeh, Haggi; Simanovsky, Natalia

    2016-04-01

    To investigate which clinical, laboratory, and CT findings potentially facilitate the differential diagnosis between tubo-ovarian abscess (TOA) and periappendicular abscess (PAA), we retrospectively reviewed abdominal CT examinations and medical records for all women who presented to our medical center with unilateral right pelvic abscess formation who underwent CT evaluation from 2004-2014. A wide spectrum of clinical data and imaging findings were recorded. CT diagnoses were made in consensus by two experienced body radiologists blinded to the final diagnosis. Findings associated with the infections were compared using the chi-square (χ(2)) or the Fisher exact test. Ninety-one patients were included; 58 with PAA (mean age 46 years) and 33 with TOA (mean age 37 years). Pain on cervical motion (67 %) and vaginal discharge (21 %) were significantly more common in TOA; other clinical signs were similar. The presence of right ovarian vein entering the mass on CT had 100 % specificity and 94 % sensitivity to TOA. Distended right fallopian tube (79 %), mass posterior to mesovarium (76 %), contralateral pelvic fat stranding (55 %), and thickening of sacrouterine ligaments (55 %) were significantly more common in TOA. Positive "arrowhead sign" (91 %), mesenteric lymphadenopathy (85 %), small bowel wall thickening (55 %), fluid in the right paracolic gutter (50 %), and cecal wall thickening (48 %) were significantly more common in PAA;internal gas was revealed only in PAA (33 %). Distinct CT features can increase diagnostic certainty regarding the origin of right lower quadrant abscess in women.

  11. The roles of atomic and molecular gas on the redshift evolution of star formation and metallicity in galaxy formation models

    NASA Astrophysics Data System (ADS)

    Fu, Jian; Kauffmann, Guinevere

    2013-03-01

    We study the redshift evolution of neutral and molecular gas in the interstellar medium with the results from semi-analytic models of galaxy formation and evolution, which track the cold gas related physical processes in radially resolved galaxy disks. Two kinds of prescriptions are adopted to describe the conversion between molecular and neutral gas in the ISM: one is related to the gas surface density and gas metallicity based on the model results by Krumholz, Mckee & Tumlinson; the other is related the pressure of ISM. We try four types of star formation laws in the models to study the effect of the molecular gas component and the star formation time scale on the model results, and find that the H2 dependent star formation rate with constant star formation efficiency is the preferred star formation law. We run the models based on both Millennium and Millennium II Simulation haloes, and the model parameters are adjusted to fit the observations at z = 0 from THINGS/HERACLES and ALFALFA/COLD GASS. We give predictions for the redshift evolution of cosmic star formation density, H2 to HI cosmic ratios, gas to star mass ratios and gas metallicity vs stellar mass relation. Based on the model results, we find that: (i) the difference in the H2 to HI ratio at z > 3 between the two H2 fraction prescriptions can help future observations to test which prescription is better; (ii) a constant redshift independent star formation time scale will postpone the star formation processes at high redshift and cause obvious redshift evolution for the relation between gas metallicity and stellar mass in galaxies at z < 3.

  12. The role of percutaneous transhepatic abscess drainage for liver abscess.

    PubMed

    Ogawa, T; Shimizu, S; Morisaki, T; Sugitani, A; Nakatsuka, A; Mizumoto, K; Yamaguchi, K; Chijiiwa, K; Tanaka, M

    1999-01-01

    To evaluate the efficacy of percutaneous transhepatic abscess drainage (PTAD) as an initial choice of treatment for liver abscess, the medical records of 28 patients with liver abscess were retrospectively analyzed. The patients were predominantly men (23 of 28) with a mean age of 59 years (range, 19-86 years). Their chief complaints were fever (86%), right hypochondralgia (32%), and jaundice (11%). Fifteen of the 28 patients (54%) had hepatobiliary and pancreatic carcinoma, and 31% had postoperative liver abscess. PTAD was performed in 23 patients and surgical drainage in 5. The overall success rate for PTAD was 83%. The success rate for PTAD for patients with multiple abscesses was 83% (5 of 6), compared with a success rate of 82% (14 of 17) for patients with solitary abscess. The prognostic factors for survival were cancer and sepsis and the mortality rate for patients with cancer was 40% (6 of 15) while the mortality rate for patients with sepsis was 56% (5 of 9). As a complication of drainage, 1 patient (4%) in the PTAD group had pleural abscess due to the transpleural puncture. Our findings support the use of PTAD as the primary treatment for liver abscess, as it is safe and effective irrespective of the number of abscesses and the patient's condition.

  13. Brain abscess: Current management

    PubMed Central

    Alvis Miranda, Hernando; Castellar-Leones, Sandra Milena; Elzain, Mohammed Awad; Moscote-Salazar, Luis Rafael

    2013-01-01

    Brain abscess (BA) is defined as a focal infection within the brain parenchyma, which starts as a localized area of cerebritis, which is subsequently converted into a collection of pus within a well-vascularized capsule. BA must be differentiated from parameningeal infections, including epidural abscess and subdural empyema. The BA is a challenge for the neurosurgeon because it is needed good clinical, pharmacological, and surgical skills for providing good clinical outcomes and prognosis to BA patients. Considered an infrequent brain infection, BA could be a devastator entity that easily left the patient into dead. The aim of this work is to review the current concepts regarding epidemiology, pathophysiology, etiology, clinical presentation, diagnosis, and management of BA. PMID:24174804

  14. Toxic levels of ammonia in human brain abscess.

    PubMed

    Dahlberg, Daniel; Ivanovic, Jugoslav; Hassel, Bjørnar

    2016-03-01

    Brain abscesses could lead to cerebral symptoms through tissue destruction, edema, changes in brain architecture, and increased intracranial pressure. However, the possibility that the pus itself could contribute to symptoms has received little attention. Brain abscesses are areas of tissue destruction, proteolysis, and formation of free amino acids, which are energy substrates for bacteria and possible sources of ammonia. Ammonia is neurotoxic, may cause brain edema, and could contribute to the symptoms of brain abscesses. The authors analyzed the extracellular phase of pus from 14 patients with brain abscesses with respect to ammonia and amino acids. For comparison, CSF from 10 patients undergoing external ventricular drainage was included. The ammonia-forming ability of Streptococcus intermedius and Staphylococcus aureus, two common microbial isolates in brain abscesses, was studied in vitro. In brain abscesses ammonia was 15.5 mmol/L (median value; range 1.7-69.2 mmol/L). In CSF ammonia was 29 μmol/L (range 17-55 μmol/L; difference from value in pus: p < 0.001). The total concentration of amino acids in brain abscesses was 1.12-16 times higher than the ammonia concentration (p = 0.011). The median glucose value in pus was 0 mmol/L (range 0-2.1 mmol/L), lactate was 21 mmol/L (range 3.3-26.5 mmol/L), and pH was 6.8 (range 6.2-7.3). In vitro, S. intermedius and S. aureus formed ammonia at 6-7 mmol/L in 24 hours when incubated with 20 proteinogenic amino acids plus g-aminobutyric acid (GABA), taurine, and glutathione at 1 mmol/L. Intracerebral abscesses contain toxic levels of ammonia. At the concentrations found in pus, ammonia could contribute to the brain edema and the symptoms of brain abscesses.

  15. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics

    PubMed Central

    Liu, Jianqiao; Gao, Yinglin; Wu, Xu; Jin, Guohua; Zhai, Zhaoxia; Liu, Huan

    2017-01-01

    The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width. PMID:28796167

  16. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics.

    PubMed

    Liu, Jianqiao; Gao, Yinglin; Wu, Xu; Jin, Guohua; Zhai, Zhaoxia; Liu, Huan

    2017-08-10

    The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.

  17. Hematogenous Pasteurella multocida brain abscess

    SciTech Connect

    Wallace, M.; Lipsky, B.A.

    1985-10-01

    A case of hematogenously acquired brain abscess caused by Pasteurella multocida is described. CT scans of the head revealed the lesions in a 67 year old man with mild alcoholic liver disease and severe chronic obstructive pulmonary disease. Ultrasound examinations of the abdomen and chest and an echocardiogram failed to reveal a source for the abscess. On autopsy examination three encapsulated brain abscesses were found. 34 references, 2 figures, 1 table.

  18. Retroperitoneal abscess: an extra-abdominal manifestation

    PubMed Central

    Mallia, Alvin James; Ashwood, Neil; Arealis, George; Galanopoulos, Ilias

    2015-01-01

    Retroperitoneal abscesses are unusual occurrences with occult and insidious presentations. There is often a lack of abdominal signs, leading to delays in drainage and high mortality rates. We report a case of thigh emphysema in an 88-year-old patient with diabetes. Prior to admission the patient reported a vague 4-week history of left thigh pain and an inability to fully weight bear. She presented to our emergency department with sepsis and acute kidney impairment. An X-ray of her left femur revealed widespread gas between muscular planes. A retroperitoneal abscess involving the left renal fossa, psoas, iliacus and upper thigh muscles was revealed on an urgent CT scan. The patient was transferred to intensive care unit (ICU) and underwent an emergency drainage. Despite ICU the patient died 2 days after admission. PMID:25576509

  19. Retroperitoneal abscess: an extra-abdominal manifestation.

    PubMed

    Mallia, Alvin James; Ashwood, Neil; Arealis, George; Galanopoulos, Ilias

    2015-01-09

    Retroperitoneal abscesses are unusual occurrences with occult and insidious presentations. There is often a lack of abdominal signs, leading to delays in drainage and high mortality rates. We report a case of thigh emphysema in an 88-year-old patient with diabetes. Prior to admission the patient reported a vague 4-week history of left thigh pain and an inability to fully weight bear. She presented to our emergency department with sepsis and acute kidney impairment. An X-ray of her left femur revealed widespread gas between muscular planes. A retroperitoneal abscess involving the left renal fossa, psoas, iliacus and upper thigh muscles was revealed on an urgent CT scan. The patient was transferred to intensive care unit (ICU) and underwent an emergency drainage. Despite ICU the patient died 2 days after admission.

  20. [Sublumbar abscesses in the dog. Retrospective evaluation of 13 patients].

    PubMed

    Kaiser, S; Thiel, C; Michalik, J; Kramer, M

    2013-01-01

    Presentation of sublumbar abscesses in the dog with regard to diagnostic and therapeutic options as well as prognosis. Retrospective evaluation of the data of 13 dogs, which were presented with sublumbar abscesses between 2002 and 2012. Young to middle-aged and middle to large breed dogs were mainly affected. The time until presentation varied from 1 day to 2 years. Symptoms were generally nonspecific. Computed tomography and sonography were normally applied for diagnosis. All dogs underwent surgery and several wound examinations; only in two cases was a single surgical intervention sufficient. In addition, after being discharged, ambulant post-operative care was usually necessary for a considerable time. In two cases, plant foreign bodies could be identified as a cause of abscess formation, and in one case a prostatic abscess and a putative prostate carcinoma were present. After surgery, 12 of 13 dogs could be discharged. Nine of them showed an unremarkable healing process, one dog had a relapse followed by an unremarkable healing process, and one dog was euthanized at the request of the owners because of a putative relapse. One animal was lost to follow-up. One dog was euthanized after two surgical procedures. Sublumbar abscesses are a rare, but a serious disease in veterinary medicine. Sectional imaging techniques and sonography are suitable for diagnosis. Treatment is often sophisticated and long-standing. However, with adequate treatment, the prognosis with regard to a complete convalescence is favorable. In most cases, the cause of abscess formation remains unclear.

  1. Peptide bond formation via glycine condensation in the gas phase.

    PubMed

    Van Dornshuld, Eric; Vergenz, Robert A; Tschumper, Gregory S

    2014-07-24

    Four unique gas phase mechanisms for peptide bond formation between two glycine molecules have been mapped out with quantum mechanical electronic structure methods. Both concerted and stepwise mechanisms, each leading to a cis and trans glycylglycine product (four mechanisms total), were examined with the B3LYP and MP2 methods and Gaussian atomic orbital basis sets as large as aug-cc-pVTZ. Electronic energies of the stationary points along the reaction pathways were also computed with explicitly correlated MP2-F12 and CCSD(T)-F12 methods. The CCSD(T)-F12 computations indicate that the electronic barriers to peptide bond formation are similar for all four mechanisms (ca. 32-39 kcal mol(-1) relative to two isolated glycine fragments). The smallest barrier (32 kcal mol(-1)) is associated with the lone transition state for the concerted mechanism leading to the formation of a trans peptide bond, whereas the largest barrier (39 kcal mol(-1)) was encountered along the concerted pathway leading to the cis configuration of the glycylglycine dipeptide. Two significant barriers are encountered for the stepwise mechanisms. For both the cis and trans pathways, the early electronic barrier is 36 kcal mol(-1) and the subsequent barrier is approximately 1 kcal mol(-1) lower. A host of intermediates and transition states lie between these two barriers, but they all have very small relative electronic energies (ca. ± 4 kcal mol(-1)). The isolated cis products (glycylglycine + H2O) are virtually isoenergetic with the isolated reactants (within -1 kcal mol(-1)), whereas the trans products are about 5 kcal mol(-1) lower in energy. In both products, however, the water can hydrogen bond to the dipeptide and lower the energy by roughly 5-9 kcal mol(-1). This study indicates that the concerted process leading to a trans configuration about the peptide bond is marginally favored both thermodynamically (exothermic by ca. 5 kcal mol(-1)) and kinetically (barrier height ≈ 32 kcal mol(-1

  2. Multi-scale gas flow in Bazhen formation shales

    NASA Astrophysics Data System (ADS)

    Vasilyev, R.; Gerke, K.; Korost, D. V.; Karsanina, M.; Balushkina, N. S.; Kalmikov, G. A.; Mallants, D.

    2013-12-01

    To perform geological surveys, estimate gas/oil productivity and create large-scale reservoir models, detailed information on reservoir rock properties is needed. Such information typically includes main reservoir properties such as absolute and relative permeability, formation factor, residual oil/water content, etc. The only available method to study all these properties directly is based on laboratory analysis of core material. Usually, only porosity measurements using such techniques as NMR and mercury porosimetry are applicable to study the structure of porous spaces filled with kerogen and bitumen. To measure porosity these organic materials should be extracted (usually by dissolution), a process which can result in sample destruction as some part of the organics is the part of the matrix (and also non-extractable during production). Thus, a pore-scale modelling approach in many cases is not only a valuable alternative, but also the only way to assess physical properties. Unlike core material, drilling cuts are almost always available for analysis and can be used for processing in the laboratory. The main aim of this work is to develop a framework for accessing unconventional reservoir rock properties using pore-scale modeling on 3D models of porous structure of cores or drilling cuts. To do so we combine detailed laboratory measurements on more than 20 samples of shales with X-ray micro-tomography and SEM to study micro and nano-porosity (including kerogen porosity). First, we show that in many cases it is not possible to measure petrophysical properties (e.g., gas permeability) in the laboratory, as dissolution procedures usually result in non-realistic values. Next samples with measurable properties were chosen and micro-tomography 3D structure data combined with SEM images was used to create representative network models. Macroporosity and distribution of different non-porosity domains (kerogen, pyrite, quartz, etc.) is extracted from X-ray tomography

  3. Treatment of anal fistula and abscess.

    PubMed

    Pigot, F

    2015-04-01

    The glands of Hermann and Desfosses, located in the thickness of the anal canal, drain into the canal at the dentate line. Infection of these anal glands is responsible for the formation of abscesses and/or fistulas. When this presents as an abscess, emergency drainage of the infected cavity is required. At the stage of fistula, treatment has two sometimes conflicting objectives: effective drainage and preservation of continence. These two opposing constraints explain the existence of two therapeutic concepts. On one hand the laying-open of the fistulous tract (fistulotomy) in one or several operative sessions remains the treatment of choice because of its high cure rates. On the other hand surgical closure with tract ligation or obturation with biological components preserves sphincter function but suffers from a higher failure rate. Copyright © 2014. Published by Elsevier Masson SAS.

  4. Distinguishing the Source of Natural Gas Accumulations with a Combined Gas and Co-produced Formation Water Geochemical Approach: a Case Study from the Appalachian Basin

    EPA Pesticide Factsheets

    The purpose of this study is to discuss the use of gas and co-produced formation water geochemistry for identifying the source of natural gas and present gas geochemistry for the northern Appalachian Basin.

  5. Amebic abscess of urachal remnants.

    PubMed

    Catanzaro, D; Mirk, P; Carbone, A; Macis, G; Danza, F M

    2001-06-01

    We report a rare case of amebic abscess of the urachus, mimicking an urachal neoplasm: no previous reports of amebic infection of the urachus were found in the literature. The challenges of the differential diagnosis between urachal abscess and carcinomas based both on clinical and radiological data are discussed.

  6. The carbon dioxide-water interface at conditions of gas hydrate formation.

    PubMed

    Lehmkühler, Felix; Paulus, Michael; Sternemann, Christian; Lietz, Daniela; Venturini, Federica; Gutt, Christian; Tolan, Metin

    2009-01-21

    The structure of the carbon dioxide-water interface was analyzed by X-ray diffraction and reflectivity at temperature and pressure conditions which allow the formation of gas hydrate. The water-gaseous CO2 and the water-liquid CO2 interface were examined. The two interfaces show a very different behavior with respect to the formation of gas hydrate. While the liquid-gas interface exhibits the formation of thin liquid CO2 layers on the water surface, the formation of small clusters of gas hydrate was observed at the liquid-liquid interface. The data obtained from both interfaces points to a gas hydrate formation process which may be explained by the so-called local structuring hypothesis.

  7. [Putaminal abscess occurring at the site of hemorrhage: a case report].

    PubMed

    Sumioka, S; Kajikawa, H; Yamamura, K; Furuse, M; Kajikawa, M; Pant, B

    1996-09-01

    Brain abscesses following stroke have been reported only rarely. We presented a case of putaminal abscess following putaminal hemorrhage. The patient was admitted to our hospital because of acute onset of left hemiplegia. The size of the hematoma was medium and the patient was conservatively treated. In about two months after the ictus, he became intermittently febrile and laboratory examinations suggested the presence of general infections including meningitis. Meanwhile, CT and MRI revealed clearly abscess formation at the site of the hematoma with remarkable brain edema. Cerebrospinal fluid analysis showed the findings of meningitis. On diagnosis of brain abscess, stereotactic exploration was performed and pus mixed with old blood was aspirated. Bacteriological study of the specimen demonstrated Morganella morganii. Postoperative course was uneventful and the abscess cavity gradually subsided following drainage and irrigation of the abscess cavity.

  8. The role of cold and hot gas flows in feeding early-type galaxy formation

    NASA Astrophysics Data System (ADS)

    Johansson, Peter H.

    2016-10-01

    We study the evolution of the gaseous components in massive simulated galaxies and show that their early formation is fuelled by cold, low entropy gas streams. At lower redshifts of z <~ 3 the simulated galaxies are massive enough to support stable virial shocks resulting in a transition from cold to hot gas accretion. The gas accretion history of early-type galaxies is directly linked to the formation of their stellar component in the two phased formation scenario, in which the central parts of the galaxy assemble rapidly through in situ star formation and the later assembly is dominated primarily by minor stellar mergers.

  9. Dental abscess: A microbiological review

    PubMed Central

    Shweta; Prakash, S Krishna

    2013-01-01

    Dental abscess is a frequently occurring infectious process known to the health practice. The fate of the infection depends on the virulence of the bacteria, host resistance factors, and regional anatomy. Serious consequences arising from the spread of a dental abscess lead to significant morbidity and mortality. Acute dental abscess is polymicrobial, comprising of strict anaerobes, such as anaerobic cocci, Prevotella, Fusobacterium species, and facultative anaerobes, such as viridans group streptococci and the Streptococcus anginosus group. Numerous novel, uncultivable and fastidious organisms have been identified as potential pathogens with the use of non-culture techniques. The majority of localized dental abscesses respond to surgical treatment while the use of antimicrobials is limited to severe spreading infections. There is a need for good-quality clinical trials of sufficient size to identify the ideal treatment. The microbiology of the acute dentoalveolar abscess and its treatment in the light of improved culture and diagnostic methods are reviewed. PMID:24348613

  10. Brucellar spondylodiscitis: comparison of patients with and without abscesses.

    PubMed

    Kaptan, Figen; Gulduren, Hakki Mustafa; Sarsilmaz, Aysegul; Sucu, Hasan Kamil; Ural, Serap; Vardar, Ilknur; Coskun, Nejat Ali

    2013-04-01

    Brucellosis is an important cause of spondylodiscitis in endemic areas. Brucellar spondylodiscitis is a serious complication because of its association with abscess formation. Prospective studies comparing patients with and without abscesses are lacking. The objective of this study was to determine the frequency and demographic, clinical, laboratory, and radiological features of brucellar spondylodiscitis and to compare patients with and without abscesses regarding treatment and outcome. Out of 135 consecutive patients with brucellosis, 31 patients with spondylodiscitis were recruited for the study. Patients were grouped according to magnetic resonance imaging findings. The frequency of spondylodiscitis was 23.0 %. Sites of involvement were lumbar (58.1 %), lumbosacral (22.6 %), cervical (9.7 %), thoracolumbar (6.5 %), and thoracic (3.2 %). Abscesses occurred in 19 (61.3 %) patients and were associated with low hemoglobin levels. Medical treatment included a combination of streptomycin (for the first 3 weeks), doxycycline, and rifampin. The total duration of treatment was 12-39 (mean 17.0 ± 8.5 SD) weeks. By 12 weeks of treatment, evidence of clinical improvement (67 vs. 28 %) and radiological regression (92 vs. 50 %) was significantly greater in patients without abscesses. The duration of treatment was longer if an abscess was present. Two female patients with abscesses required surgical intervention. Both patients presented with high fever, neurologic deficit, and high Brucella standard tube agglutination test titers. Each patient should be evaluated individually, based on clinical findings, laboratory data, and radiological results, when undergoing treatment for brucellar spondylodiscitis. If abscesses are found, a longer course of treatment and even surgical intervention may be needed.

  11. Genome Sequence of the Human Abscess Isolate Streptococcus intermedius BA1.

    PubMed

    Planet, Paul J; Rampersaud, Ryan; Hymes, Saul R; Whittier, Susan; Della-Latta, Phyllis A; Narechania, Apurva; Daugherty, Sean C; Santana-Cruz, Ivette; Desalle, Robert; Ravel, Jacques; Ratner, Adam J

    2013-01-01

    Streptococcus intermedius is a human pathogen with a propensity for abscess formation. We report a high-quality draft genome sequence of S. intermedius strain BA1, an isolate from a human epidural abscess. This sequence provides insight into the biology of S. intermedius and will aid investigations of pathogenicity.

  12. Genome Sequence of the Human Abscess Isolate Streptococcus intermedius BA1

    PubMed Central

    Planet, Paul J.; Rampersaud, Ryan; Hymes, Saul R.; Whittier, Susan; Della-Latta, Phyllis A.; Narechania, Apurva; Daugherty, Sean C.; Santana-Cruz, Ivette; DeSalle, Robert; Ravel, Jacques

    2013-01-01

    Streptococcus intermedius is a human pathogen with a propensity for abscess formation. We report a high-quality draft genome sequence of S. intermedius strain BA1, an isolate from a human epidural abscess. This sequence provides insight into the biology of S. intermedius and will aid investigations of pathogenicity. PMID:23405291

  13. THE STATE OF THE GAS AND THE RELATION BETWEEN GAS AND STAR FORMATION AT LOW METALLICITY: THE SMALL MAGELLANIC CLOUD

    SciTech Connect

    Bolatto, Alberto D.; Jameson, Katherine; Ostriker, Eve; Leroy, Adam K.; Indebetouw, Remy; Gordon, Karl; Lawton, Brandon; Roman-Duval, Julia; Stanimirovic, Snezana; Israel, Frank P.; Madden, Suzanne C.; Hony, Sacha; Bot, Caroline; Rubio, Monica; Winkler, P. Frank; Van Loon, Jacco Th.; Oliveira, Joana M.

    2011-11-01

    We compare atomic gas, molecular gas, and the recent star formation rate (SFR) inferred from H{alpha} in the Small Magellanic Cloud (SMC). By using infrared dust emission and local dust-to-gas ratios, we construct a map of molecular gas that is independent of CO emission. This allows us to disentangle conversion factor effects from the impact of metallicity on the formation and star formation efficiency of molecular gas. On scales of 200 pc to 1 kpc (where the distributions of H{sub 2} and star formation match well) we find a characteristic molecular gas depletion time of {tau}{sup mol} d{sub ep} {approx} 1.6 Gyr, similar to that observed in the molecule-rich parts of large spiral galaxies on similar spatial scales. This depletion time shortens on much larger scales to {approx}0.6 Gyr because of the presence of a diffuse H{alpha} component, and lengthens on much smaller scales to {approx}7.5 Gyr because the H{alpha} and H{sub 2} distributions differ in detail. We estimate the systematic uncertainties in our dust-based {tau}{sup mol}{sub dep} measurement to be a factor of {approx}2-3. We suggest that the impact of metallicity on the physics of star formation in molecular gas has at most this magnitude, rather than the factor of {approx}40 suggested by the ratio of SFR to CO emission. The relation between SFR and neutral (H{sub 2} + H{sub i}) gas surface density is steep, with a power-law index {approx}2.2 {+-} 0.1, similar to that observed in the outer disks of large spiral galaxies. At a fixed total gas surface density the SMC has a 5-10 times lower molecular gas fraction (and star formation rate) than large spiral galaxies. We explore the ability of the recent models by Krumholz et al. and Ostriker et al. to reproduce our observations. We find that to explain our data at all spatial scales requires a low fraction of cold, gravitationally bound gas in the SMC. We explore a combined model that incorporates both large-scale thermal and dynamical equilibrium and cloud

  14. [Clinical analysis of nasogenic brain abscess].

    PubMed

    Yu, Huanxin; Liu, Gang

    2014-03-01

    To investigate the clinical features of nasogenic brain abscess. Four patients with nasogenic brain abscess diagnosed in Tianjin huanhu hospital between June 2007 and January 2013 were reported and the relevant literatures reviewed. All four patients were frontal abscess, however, the pathogeny of frontal abscess were different. These four patients were treated by different methods and followed up from 12-28 months, no recurrence was found. All four patients were cured. The clinical manifestation of nasogenic brain abscess was hiding and was easy to misdiagnosis. Enhanced MRI is the key of the diagnosis. According to the pathogeny of brain abscess, it was important to cure nasogenic brain abscess with different ways.

  15. Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

    NASA Astrophysics Data System (ADS)

    Hu, Shenyang; Burkes, Douglas E.; Lavender, Curt A.; Senor, David J.; Setyawan, Wahyu; Xu, Zhijie

    2016-10-01

    Nano-gas bubble superlattices are often observed in irradiated UMo nuclear fuels. However, the formation mechanism of gas bubble superlattices is not well understood. A number of physical processes may affect the gas bubble nucleation and growth; hence, the morphology of gas bubble microstructures including size and spatial distributions. In this work, a phase-field model integrating a first-passage Monte Carlo method to investigate the formation mechanism of gas bubble superlattices was developed. Six physical processes are taken into account in the model: 1) heterogeneous generation of gas atoms, vacancies, and interstitials informed from atomistic simulations; 2) one-dimensional (1-D) migration of interstitials; 3) irradiation-induced dissolution of gas atoms; 4) recombination between vacancies and interstitials; 5) elastic interaction; and 6) heterogeneous nucleation of gas bubbles. We found that the elastic interaction doesn't cause the gas bubble alignment, and fast 1-D migration of interstitials along <110> directions in the body-centered cubic U matrix causes the gas bubble alignment along <110> directions. It implies that 1-D interstitial migration along [110] direction should be the primary mechanism of a fcc gas bubble superlattice which is observed in bcc UMo alloys. Simulations also show that fission rates, saturated gas concentration, and elastic interaction all affect the morphology of gas bubble microstructures.

  16. The Dense-gas Mass versus Star Formation Rate Relation: A Misleading Linearity?

    NASA Astrophysics Data System (ADS)

    Parmentier, G.

    2017-07-01

    We model the star formation relation of molecular clumps in dependence of their dense-gas mass when their volume density profile is that of an isothermal sphere (i.e., {ρ }{clump}(r)\\propto {r}-2). Dense gas is defined as gas whose volume density is higher than a threshold {ρ }{th}=700 {M}⊙ {{pc}}-3 (i.e., HCN(1-0)-mapped gas). We divide the clump into two regions: a dense inner region (where {ρ }{clump}(r)≥slant {ρ }{th}), and low-density outskirts (where {ρ }{clump}(r)< {ρ }{th}). We find that the total star formation rate of clumps scales linearly with the mass of their dense inner region, even when more than half of the clump star formation activity takes place in the low-density outskirts. We therefore emphasize that a linear star formation relation does not necessarily imply that star formation takes place exclusively in the gas whose mass is given by the star formation relation. The linearity of the star formation relation is strengthened when we account for the mass of dense fragments (e.g., cores, fibers) seeding star formation in the low-density outskirts, and which our adopted clump density profile {ρ }{clump}(r) does not resolve. We also find that the star formation relation is significantly tighter when considering the dense gas than when considering all the clump gas, as observed for molecular clouds of the Galactic plane. When the clumps have no low-density outskirts (i.e., they consist of dense gas only), the star formation relation becomes superlinear and progressively wider.

  17. Pyogenic Brain Abscess in Thailand

    PubMed Central

    Wiwanitkit, Somsri; Wiwanitkit, Viroj

    2012-01-01

    Pyogenic brain abscess is important in neurology. This infectious disease is fatal and the management is usually complicated. Here, the authors review and discuss the clinical aspects of pyogenic brain abscess found in the earlier reports from a tropical setting in Thailand. The literature review was compiled through standard reference database searching and the derived publications were further extracted to obtain clinical data. The main clinical characteristics of pyogenic brain abscess in this setting were similar to others. However, there are some specific characteristics on the nature of tropical setting. PMID:22754873

  18. Formation of chlorinated lipids post-chlorine gas exposure.

    PubMed

    Ford, David A; Honavar, Jaideep; Albert, Carolyn J; Duerr, Mark A; Oh, Joo Yeun; Doran, Stephen; Matalon, Sadis; Patel, Rakesh P

    2016-08-01

    Exposure to chlorine (Cl2) gas can occur during accidents and intentional release scenarios. However, biomarkers that specifically indicate Cl2 exposure and Cl2-derived products that mediate postexposure toxicity remain unclear. We hypothesized that chlorinated lipids (Cl-lipids) formed by direct reactions between Cl2 gas and plasmalogens serve as both biomarkers and mediators of post-Cl2 gas exposure toxicities. The 2-chloropalmitaldehyde (2-Cl-Pald), 2-chlorostearaldehyde (2-Cl-Sald), and their oxidized products, free- and esterified 2-chloropalmitic acid (2-Cl-PA) and 2-chlorostearic acid were detected in the lungs and plasma of mouse and rat models of Cl2 gas exposure. Levels of Cl-lipids were highest immediately post-Cl2 gas exposure, and then declined over 72 h with levels remaining 20- to 30-fold higher at 24 h compared with baseline. Glutathione adducts of 2-Cl-Pald and 2-Cl-Sald also increased with levels peaking at 4 h in plasma. Notably, 3-chlorotyrosine also increased after Cl2 gas exposure, but returned to baseline within 24 h. Intranasal administration of 2-Cl-PA or 2-Cl-Pald at doses similar to those formed in the lung after Cl2 gas exposure led to increased distal lung permeability and inflammation and systemic endothelial dysfunction characterized by loss of eNOS-dependent vasodilation. These data suggest that Cl-lipids could serve as biomarkers and mediators for Cl2 gas exposure and toxicity. Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc.

  19. Gas Bubble Formation in Stagnant and Flowing Mercury

    SciTech Connect

    Wendel, Mark W; Abdou, Ashraf A; Riemer, Bernie; Felde, David K

    2007-01-01

    Investigations in the area of two-phase flow at the Oak Ridge National Laboratory's (ORNL) Spallation Neutron Source (SNS) facility are progressing. It is expected that the target vessel lifetime could be extended by introducing gas into the liquid mercury target. As part of an effort to validate the two-phase computational fluid dynamics (CFD) model, simulations and experiments of gas injection in stagnant and flowing mercury have been completed. The volume of fluid (VOF) method as implemented in ANSYS-CFX, was used to simulate the unsteady two-phase flow of gas injection into stagnant mercury. Bubbles produced at the upwards-oriented vertical gas injector were measured with proton radiography at the Los Alamos Neutron Science Center. The comparison of the CFD results to the radiographic images shows good agreement for bubble sizes and shapes at various stages of the bubble growth, detachment, and gravitational rise. Although several gas flows were measured, this paper focuses on the case with a gas flow rate of 8 cc/min through the 100-micron-diameter injector needle. The acoustic waves emitted due to the detachment of the bubble and during subsequent bubble oscillations were recorded with a microphone, providing a precise measurement of the bubble sizes. As the mercury flow rate increases, the drag force causes earlier bubble detachment and therefore smaller bubbles.

  20. Spinal epidural abscess.

    PubMed

    Krishnamohan, Prashanth; Berger, Joseph R

    2014-11-01

    Spinal epidural abscess (SEA) remains a relatively infrequent diagnosis. Staphylococcus aureus is the most common organism identified, and the infectious source in SEA emanates from skin and soft tissue infections in about 20 % of instances. The thoracic spine is most often involved followed by the lumbar spine. The classic triad of fever, spinal pain, and neurological deficit is present in but a minority of patients. The appearance of neurological deficits with SEA has a significant impact on the prognosis; therefore, early diagnosis is imperative. Magnetic resonance imaging has permitted earlier diagnosis, although significant delays in diagnosis are common due to the nonspecific symptoms that frequently attend the disorder. Due to the rarity of this condition, there have been few randomized controlled trials to evaluate new treatment strategies, and most recommendations regarding treatment are based on case series studies often derived from the experiences at a single center.

  1. Gas hydrate formation in the deep sea: In situ experiments with controlled release of methane, natural gas, and carbon dioxide

    USGS Publications Warehouse

    Brewer, P.G.; Orr, F.M.; Friederich, G.; Kvenvolden, K.A.; Orange, D.L.

    1998-01-01

    We have utilized a remotely operated vehicle (ROV) to initiate a program of research into gas hydrate formation in the deep sea by controlled release of hydrocarbon gases and liquid CO2 into natural sea water and marine sediments. Our objectives were to investigate the formation rates and growth patterns of gas hydrates in natural systems and to assess the geochemical stability of the reaction products over time. The novel experimental procedures used the carrying capacity, imaging capability, and control mechanisms of the ROV to transport gas cylinders to depth and to open valves selectively under desired P-T conditions to release the gas either into contained natural sea water or into sediments. In experiments in Monterey Bay, California, at 910 m depth and 3.9??C water temperature we find hydrate formation to be nearly instantaneous for a variety of gases. In sediments the pattern of hydrate formation is dependent on the pore size, with flooding of the pore spaces in a coarse sand yielding a hydrate cemented mass, and gas channeling in a fine-grained mud creating a veined hydrate structure. In experiments with liquid CO2 the released globules appeared to form a hydrate skin as they slowly rose in the apparatus. An initial attempt to leave the experimental material on the sea floor for an extended period was partially successful; we observed an apparent complete dissolution of the liquid CO2 mass, and an apparent consolidation of the CH4 hydrate, over a period of about 85 days.

  2. Suppression of formation of dioxins in combustion gas of municipal waste incinerators by spray water injection.

    PubMed

    Kubota, Eiji; Shigechi, Toru; Takemasa, Takehiro; Momoki, Satoru; Arizono, Koji

    2007-01-01

    Dioxins in the combustion gas of municipal solid waste incinerators (MSWIs) are resynthesized when the combustion gas passes from the outlet exaust gas boiler to the outlet gas duct. The objective of the study was to estimate if the suppression of the formation of dioxins depends on the inlet gas temperature and diameter and/or temperature of droplet spray water using an actual incinerator operation data. The dioxin formation and/or the quenching temperature is revealed using the Altwicker theory equation with the information of inlet gas temperature and droplet spray water. The evaporation rate of a spray water droplet also can be estimated using the Mizutani theory. The highest dioxin formation was found at 350 degrees C; thereafter, it decreased quickly. When an area of 500 microm for droplet-formed dioxins is defined as 100%, the values of formed dioxins for 400, 300, 200 and 100 microm droplet areas are estimated as 71, 41, 25 and 18%, respectively. It is revealed that the smaller size of droplet spray water and lower inlet gas temperature enable the decrease in dioxin formation. The decreased dioxin formation and/or the lower quenching temperature is revealed using the Altwicker theory equation with the information of inlet gas temperature and droplet spray water size.

  3. Measurements of gas hydrate formation probability distributions on a quasi-free water droplet

    NASA Astrophysics Data System (ADS)

    Maeda, Nobuo

    2014-06-01

    A High Pressure Automated Lag Time Apparatus (HP-ALTA) can measure gas hydrate formation probability distributions from water in a glass sample cell. In an HP-ALTA gas hydrate formation originates near the edges of the sample cell and gas hydrate films subsequently grow across the water-guest gas interface. It would ideally be desirable to be able to measure gas hydrate formation probability distributions of a single water droplet or mist that is freely levitating in a guest gas, but this is technically challenging. The next best option is to let a water droplet sit on top of a denser, immiscible, inert, and wall-wetting hydrophobic liquid to avoid contact of a water droplet with the solid walls. Here we report the development of a second generation HP-ALTA which can measure gas hydrate formation probability distributions of a water droplet which sits on a perfluorocarbon oil in a container that is coated with 1H,1H,2H,2H-Perfluorodecyltriethoxysilane. It was found that the gas hydrate formation probability distributions of such a quasi-free water droplet were significantly lower than those of water in a glass sample cell.

  4. Impact of gas formation kinetics on dough development and bread quality.

    PubMed

    Verheyen, C; Albrecht, A; Elgeti, D; Jekle, M; Becker, T

    2015-10-01

    The baking performance and gas retention capacity of wheat dough depends on production rate and total volume of CO2 during fermentation. This study aims to examine the effect of the CO2 formation kinetics and the gas volume fraction on the structural integrity of wheat dough and the resulting bread quality. The gas release characteristics were evaluated using a rheofermentometer with varied concentrations of compressed yeast and instant dry yeast (CY and IDY respectively). For this purpose, the maximum CO2 formation rate was calculated through the derivation of hydrostatic pressure curves measured in the rheofermentometer. For CY, the time when gas escapes the dough matrix (Tx, time of porosity) as well as the corresponding gas volume depended on the gas formation rate, whereas the gas retention capacity of wheat dough leavened with IDY was not affected by the CO2 formation rate. Although the dough leavened with IDY showed improved extensibility during fermentation, the specific bread volume was 21% below that of the samples leavened with CY. These results indicate that an increase in the maximum gas formation rate considerably affects the structural integrity of the dough matrix. Because of the reduction of the loaf volume, the effect is reinforced by the application of IDY. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Measurements of gas hydrate formation probability distributions on a quasi-free water droplet.

    PubMed

    Maeda, Nobuo

    2014-06-01

    A High Pressure Automated Lag Time Apparatus (HP-ALTA) can measure gas hydrate formation probability distributions from water in a glass sample cell. In an HP-ALTA gas hydrate formation originates near the edges of the sample cell and gas hydrate films subsequently grow across the water-guest gas interface. It would ideally be desirable to be able to measure gas hydrate formation probability distributions of a single water droplet or mist that is freely levitating in a guest gas, but this is technically challenging. The next best option is to let a water droplet sit on top of a denser, immiscible, inert, and wall-wetting hydrophobic liquid to avoid contact of a water droplet with the solid walls. Here we report the development of a second generation HP-ALTA which can measure gas hydrate formation probability distributions of a water droplet which sits on a perfluorocarbon oil in a container that is coated with 1H,1H,2H,2H-Perfluorodecyltriethoxysilane. It was found that the gas hydrate formation probability distributions of such a quasi-free water droplet were significantly lower than those of water in a glass sample cell.

  6. Reducing Mechanical Formation Damage by Minimizing Interfacial Tension and Capillary Pressure in Tight Gas

    NASA Astrophysics Data System (ADS)

    Ahmed, Arshad; Talib Shuker, Muhannad; Rehman, Khalil; Bahrami, Hassan; Memon, Muhammad Khan

    2013-12-01

    Tight gas reservoirs incur problems and significant damage caused by low permeability during drilling, completion, stimulation and production. They require advanced improvement techniques to achieve flow gas at optimum rates. Water blocking damage (phase Trapping/retention of fluids) is a form of mechanical formation damage mechanism, which is caused by filtrate invasion in drilling operations mostly in fracturing. Water blocking has a noticeable impact on formation damage in gas reservoirs which tends to decrease relative permeability near the wellbore. Proper evaluation of damage and the factors which influence its severity is essential to optimize well productivity. Reliable data regarding interfacial tension between gas and water is required in order to minimize mechanical formation damage potential and to optimize gas production. This study was based on the laboratory experiments of interfacial tension by rising drop method between gas-brine, gas-condensate and gas-brine. The results showed gas condensate has low interfacial tension value 6 - 11 dynes/cm when compared to gas-brine and gas- diesel which were 44 - 58 dynes/cm and 14 - 19 dynes/cm respectively. In this way, the capillary pressure of brine-gas system was estimated as 0.488 psi, therefore diesel-gas system was noticed about 0.164 psi and 0.098 psi for condensate-gas system. A forecast model was used by using IFT values to predict the phase trapping which shows less severe phase trapping damage in case of condensate than diesel and brine. A reservoir simulation study was also carried out in order to better understand the effect of hysteresis on well productivity and flow efficiency affected due to water blocking damage in tight gas reservoirs.

  7. Multiple Liver Abscesses Associated with Ventriculoperitoneal Shunt Infection: Case Report and Review of the Literature

    PubMed Central

    Yang, Tae Ki

    2013-01-01

    Liver abscess following ventriculoperitoneal (VP) shunting occurs very rarely. We report an unusual case of multiple liver abscesses caused by Staphylococcus capitis in a 50-year-old compromised woman due to a complicating VP shunt infection. We reviewed the nine cases of VP shunt complications reported in the English literature, and speculated that the most likely pathogenetic mechanism in our case is an infected peritoneal tip that migrated to and penetrated the liver, which subsequently caused the formation of multiple liver abscesses. The patient was successfully treated with percutaneous aspiration, drainage of the abscesses, intravenous antibiotics, and shunt revision. Awareness and vigilance of the possibility of liver abscess formation caused by VP shunt infection will help establish an early accurate diagnosis and therapeutic strategy. PMID:24379956

  8. A fundamental study of gas formation and migration during leakage of stored carbon dioxide in subsurface formations

    NASA Astrophysics Data System (ADS)

    Sakaki, T.; Plampin, M. R.; Lassen, R. N.; Pawar, R. J.; Komatsu, M.; Jensen, K. H.; Illangasekare, T. H.

    2011-12-01

    Geologic sequestration of CO2 has received significant attention as a potential method for reducing the release of greenhouse gases into the atmosphere. Potential risk of leakage of the stored CO2 to the shallow zones of the subsurface is one of the critical issues that is needed to be addressed to design effective field storage systems. If a leak occurs, gaseous CO2 reaching shallow zones of the subsurface can potentially impact the surface and groundwater sources and vegetation. With a goal of developing models that can predict these impacts, a research study is underway to improve our understanding of the fundamental processes of gas-phase formation and multi-phase flow dynamics during CO2 migration in shallow porous media. The approach involves conducting a series of highly controlled experiments in soil columns and tanks to study the effects of soil properties, temperature, pressure gradients and heterogeneities on gas formation and migration. This paper presents the results from a set of column studies. A 3.6m long column was instrumented with 16 soil moisture sensors, 15 of which were capable of measuring electrical conductivity (EC) and temperature, eight water pressure, and two gas pressure sensors. The column was filled with test sands with known hydraulic and retention characteristics with predetermined packing configurations. Deionized water saturated with CO2 under ~0.3 kPa (roughly the same as the hydrostatic pressure at the bottom of the column) was injected at the bottom of the column using a peristaltic pump. Water and gas outflow at the top of the column were monitored continuously. The results, in general, showed that 1) gas phase formation can be triggered by multiple factors such as water pressure drop, temperature rise, and heterogeneity, 2) transition to gas phase tends to occur rather within a short period of time, 3) gas phase fraction was as high as ~40% so that gas flow was not via individual bubble movement but two-phase flow, 4) water

  9. Tight gas sand production from the Almond Formation, Washakie Basin, Wyoming

    SciTech Connect

    Iverson, W.P.; Surdam, R.C.

    1995-12-31

    Gas production from the Almond Formation in the Standard Draw trend can only be accounted for by draining numerous layers of tight gas sands via the permeable upper bar sand. Discovery of this field originally focused upon production from this bar sand. But continued development cannot be explained simply by considering depletion of a 30 foot sand. Gas volumetrics verify the need to include lower sands in reservoir analysis. Core obtained from the Almond bar sand confirm petrophysical constants used in the authors` models. Their results imply that economic levels of gas production should be possible wherever a similar horizontal conduit can be tied into gas saturated layers through massive hydraulic fracturing.

  10. Peritonsillar abscess: clinical aspects of microbiology, risk factors, and the association with parapharyngeal abscess.

    PubMed

    Klug, Tejs Ehlers

    2017-03-01

    transportation of appropriate specimens, choice of methodology for detection and quantification of microorganisms, current or recent antibiotic treatment of patients, potential shift in significant pathogens during the course of infection, and factors associated with increased risk of PTA development.  The trend towards de-escalated surgical intervention and increasing reliance on antibiotic treatment, require studies defining the significant pathogens in PTA in order to determine optimal antibiotic regimens. Complications secondary to PTA may be avoided or better controlled with improved knowledge concerning the significant pathogens in PTA. Furthermore, identification of pathogens other than GAS, may lead the way for earlier bacterial diagnosis and timely intervention before abscess formation in sore throat patients. The identification and quantification of risk factors for PTA development constitutes another approach to reduce the incidence of PTA. As clinicians, we noticed that FN was recovered from PTA patients with increasing frequency and that patients infected with Fusobacterium necrophorum (FN) seemed to be more severely affected than patients infected with other bacteria. Furthermore, we occationally observed concomitant PPA in addition to a PTA, which made us hypothesize that PPA and PTA is often closely related and may share significant pathogens. Hence, our aims were: 1. To explore the microbiology of PTA with a special attention to Fusobacterium necrophorum (FN). 2. To elucidate whether smoking, age, gender, and seasons are risk factors for the development of PTA. 3. To characterize patients with PPA, explore the relationship between PPA and PTA, identify the pathogens associated with PPA, and review our management of PPA. In a retrospective study on all 847 PTA patients admitted to the ENT department at Aarhus University Hospital (AUH) from 2001 to 2006, we found that FN was the most prevalent (23%) bacterial strain in pus specimens. FN-positive patients

  11. [Prostatic abscess: diagnosis and treatment].

    PubMed

    Franco, A; Menéndez, V; Luque, M P; Ribal, M J; Mallafre, J M; Alcover, J; Vilana, R; Carretero, P

    1996-02-01

    Prostatic abscesses are an infrequent pathology, probably due to a better and early management of prostatic infections. Predisposing factors in this pathology are diabetes mellitus, urethral catheterism or manipulation, and immunodepressed states like AIDS. Nowadays, ultrasonography is an excellent diagnostic method of this pathology, and serves as a guidance of directed drainage. We present five cases in which the size of the abscess was determining in relation to the therapeutic attitude. Abscesses of less than 2 cm, measured by transrectal ultrasonography, can be evacuated by directed puncture, followed by antibiotic treatment. When the diameter of the abscess is greater than 2 cm, we realize a perineal drainage with a catheter placed with transrectal ultrasonography. Currently, TUR and other methods seems to be overcome.

  12. Intramedullary Cervical Spinal Cord Abscess.

    PubMed

    Bakhsheshian, Joshua; Kim, Paul E; Attenello, Frank J

    2017-10-01

    Intramedullary spinal cord abscesses are rarely encountered in modern neurosurgical practice. Select patients are at high risk for developing an intramedullary spinal cord abscess, which can result in acute neurologic deficits. Patients with failed conservative management may benefit from early surgical intervention; however, the evidence is limited by level 3 studies. In this case presentation, the patient failed conservative management for a cervical intramedullary spinal cord abscess and developed acute neurologic deficits. The decision was made to perform an urgent cervical laminectomy and drainage to avoid any further decline that may have occurred with continued conservative management. Increased awareness of intramedullary spinal cord abscess is warranted for its clinical suspicion and emergent treatment in select circumstances. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Cerebral abscess of odontogenic origin.

    PubMed

    Mylonas, Anastassios I; Tzerbos, Fotios H; Mihalaki, Maria; Rologis, Dimitrios; Boutsikakis, Iossif

    2007-01-01

    Cerebral abscess is a rare but serious and life-threatening infection. Dental infections have occasionally been reported as the source of bacteria for such an abcess. A 54-year-old man was admitted with a right hemiparesis and epileptic fits. After clinical, laboratory and imaging examination, the diagnosis of a cerebral abscess of the left parietal lobe was made. The intraoral clinical examination as well as a panoramic radiograph confirmed the presence of generalized periodontal disease, multiple dental caries, and periapical pathology. The treatment included: (i) Immediate administration of high-dose intravenous antibiotics and (ii) surgical procedures consisting of craniotomy and resection of the abscess cavity first, and secondly removal of the periodontal, decayed and periapically involved teeth of the patient, in an effort to eradicate all the possible septic foci, presuming the cerebral abscess to be of odontogenic infection. The patient made an uneventful recovery, and 29 months postoperatively he had completely recovered from the hemiparesis.

  14. Novel Peritonsillar Abscess Task Simulator.

    PubMed

    Taylor, Steven R; Chang, C W David

    2014-07-01

    The management of peritonsillar abscesses is a skill developed early in residency training. Although drainage is not technically complicated, the procedure is intimidating to the neophyte. Task simulators have become increasingly common to provide training opportunities in a controlled environment. The authors designed a peritonsillar abscess simulator using a latex moulage of the oral cavity and other common materials. Twelve medical professionals of various levels of experience were instructed to expose, anesthetize, aspirate, and drain the simulated abscess. After completion, a questionnaire was completed by each volunteer. Initial impressions were positive that the model adequately replicated the tasks requisite for abscess drainage and was suitable as an instructional device. The initial construct cost was approximately 10 dollars, with disposables costing roughly 25 cents. Further research is under way to formally assess the simulator for face, content, and construct validity. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2014.

  15. Gas in Debris Disks: Clues to the Late Stages of Planet Formation

    NASA Technical Reports Server (NTRS)

    Roberg, A.

    2008-01-01

    The basic character of debris disks was established soon after their discovery in the mid-80's. These disks around nearby main sequence stars are composed of material produced by collisions and/or evaporation of extrasolar asteroids and comets. Debris disks appear to be largely composed of dust, though little is known about its typical composition. Nonetheless, at least some debris disks have detectable gas, which has very different characteristics from the gas in younger protoplanetary disks. The gas component has resisted observation, but appears to hold important clues to the composition of extrasolar planetesimals during the late-stages of planetary system formation and the formation of terrestrial planet atmospheres. In this talk, I will explain our current understanding of the place of debris disks in the planet formation process and describe what is known about the gas component. Finally, I will outline upcoming opportunities for sensitive new studies of gas in debris disks.

  16. Gas in Debris Disks: Clues to the Late Stages of Planet Formation

    NASA Technical Reports Server (NTRS)

    Roberg, A.

    2008-01-01

    The basic character of debris disks was established soon after their discovery in the mid-80's. These disks around nearby main sequence stars are composed of material produced by collisions and/or evaporation of extrasolar asteroids and comets. Debris disks appear to be largely composed of dust, though little is known about its typical composition. Nonetheless, at least some debris disks have detectable gas, which has very different characteristics from the gas in younger protoplanetary disks. The gas component has resisted observation, but appears to hold important clues to the composition of extrasolar planetesimals during the late-stages of planetary system formation and the formation of terrestrial planet atmospheres. In this talk, I will explain our current understanding of the place of debris disks in the planet formation process and describe what is known about the gas component. Finally, I will outline upcoming opportunities for sensitive new studies of gas in debris disks.

  17. Supersonic gas streams enhance the formation of massive black holes in the early universe

    NASA Astrophysics Data System (ADS)

    Hirano, Shingo; Hosokawa, Takashi; Yoshida, Naoki; Kuiper, Rolf

    2017-09-01

    The origin of super-massive black holes in the early universe remains poorly understood. Gravitational collapse of a massive primordial gas cloud is a promising initial process, but theoretical studies have difficulty growing the black hole fast enough. We report numerical simulations of early black hole formation starting from realistic cosmological conditions. Supersonic gas motions left over from the Big Bang prevent early gas cloud formation until rapid gas condensation is triggered in a protogalactic halo. A protostar is formed in the dense, turbulent gas cloud, and it grows by sporadic mass accretion until it acquires 34,000 solar masses. The massive star ends its life with a catastrophic collapse to leave a black hole—a promising seed for the formation of a monstrous black hole.

  18. Supersonic gas streams enhance the formation of massive black holes in the early universe.

    PubMed

    Hirano, Shingo; Hosokawa, Takashi; Yoshida, Naoki; Kuiper, Rolf

    2017-09-29

    The origin of super-massive black holes in the early universe remains poorly understood. Gravitational collapse of a massive primordial gas cloud is a promising initial process, but theoretical studies have difficulty growing the black hole fast enough. We report numerical simulations of early black hole formation starting from realistic cosmological conditions. Supersonic gas motions left over from the Big Bang prevent early gas cloud formation until rapid gas condensation is triggered in a protogalactic halo. A protostar is formed in the dense, turbulent gas cloud, and it grows by sporadic mass accretion until it acquires 34,000 solar masses. The massive star ends its life with a catastrophic collapse to leave a black hole-a promising seed for the formation of a monstrous black hole. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  19. CO2 + N2O mixture gas hydrate formation kinetics and effect of soil minerals on mixture-gas hydrate formation process

    NASA Astrophysics Data System (ADS)

    Enkh-Amgalan, T.; Kyung, D.; Lee, W.

    2012-12-01

    CO2 mitigation is one of the most pressing global scientific topics in last 30 years. Nitrous oxide (N2O) is one of the main greenhouse gases (GHGs) defined by the Kyoto Protocol and its global warming potential (GWP) of one metric ton is equivalent to 310 metric tons of CO2. They have similar physical and chemical properties and therefore, mixture-gas (50% CO2 + 50% N2O) hydrate formation process was studied experimentally and computationally. There were no significant research to reduce N20 gas and we tried to make hydrate to mitigate N20 and CO2 in same time. Mixture gas hydrate formation periods were approximately two times faster than pure N2O hydrate formation kinetic in general. The fastest induction time of mixture-gas hydrate formation observed in Illite and Quartz among various soil mineral suspensions. It was also observed that hydrate formation kinetic was faster with clay mineral suspensions such as Nontronite, Sphalerite and Montmorillonite. Temperature and pressure change were not significant on hydrate formation kinetic; however, induction time can be significantly affected by various chemical species forming under the different suspension pHs. The distribution of chemical species in each mineral suspension was estimated by a chemical equilibrium model, PHREEQC, and used for the identification of hydrate formation characteristics in the suspensions. With the experimental limitations, a study on the molecular scale modeling has a great importance for the prediction of phase behavior of the gas hydrates. We have also performed molecular dynamics computer simulations on N2O and CO2 hydrate structures to estimate the residual free energy of two-phase (hydrate cage and guest molecule) at three different temperature ranges of 260K, 273K, and 280K. The calculation result implies that N2O hydrates are thermodynamically stable at real-world gas hydrate existing condition within given temperature and pressure. This phenomenon proves that mixture-gas could be

  20. How Does Dense Molecular Gas Contribute to Star Formation in the Starburst Galaxy NGC 2146?

    NASA Astrophysics Data System (ADS)

    Wofford, Alia

    2017-01-01

    The starburst galaxy NGC 2146 is believed to have been formed approximately 800 Myr ago, when two galaxies collided with each other possibly leading to a burst of star formation. NGC 2146 is known as a starburst galaxy for the high frequency of star formation going on in its molecular clouds. These clouds serve as nurseries for star formation to occur. Hydrogen Cyanide (HCN) and Carbon monoxide (CO) are molecules found in molecular gas clouds. HCN molecules are tracers for high density star forming gas. Whereas, CO molecules are tracers for low density star forming gas. In this project, we are observing these two molecules and their proximity to where the stars are forming in the galaxy to determine if the star formation is occurring in the same area as the high and low density molecular gas areas in starburst galaxy NGC 2146.

  1. Pizza or Pancake? Formation Models of Gas Escape Biosignatures in Terrestrial and Martian Sediments

    NASA Astrophysics Data System (ADS)

    Bonaccorsi, R.; Fairen, A. G.; Baker, L.; McKay, C. P.; Willson, D.

    2016-05-01

    Fine-grained sedimentary hollowed structures were imaged in Gale Crater, but no biomarkers identified to support biology. Our observation-based (gas escape) terrestrial model could inform on possible martian paleoenvironments at time of formation.

  2. Systemic infection and splenic abscess

    PubMed Central

    Guileyardo, Joseph

    2017-01-01

    Splenic abscess is a rare complication of systemic infection, sometimes associated with infective endocarditis. Due to its rarity and nonspecific symptoms, diagnosis is difficult. Antibiotic therapy alone is usually unsuccessful, and definitive treatment requires splenectomy, although percutaneous ultrasound-guided drainage has been successful in some patients. Abdominal computed tomography scans and ultrasound evaluation are usually diagnostic. We present two patients with treatment-resistant sepsis who were found at autopsy to have splenic abscess.

  3. [Nocardia brain abscess: features, therapeutic strategies and outcome].

    PubMed

    Marnet, D; Brasme, L; Peruzzi, P; Bazin, A; Diallo, R; Servettaz, A; Bernard, M-H; Rousseaux, P; de Champs, C; Jaussaud, R; Scherpereel, B

    2009-01-01

    Nocardia species is an aerobic soil-saprophyte bacterium, responsible for rare opportunistic infections, mainly reported in immunocompromised patients. Nocardia brain abscess accounts for 1 to 2% of cerebral abscesses. Prognosis is poor. We describe clinical, radiological and bacteriological findings along with therapeutic aspects for five patients and review the literature on Nocardia cerebral abscess. The clinical features of Nocardia brain abscess are insidious and nonspecific, occurring frequently with a medical background of obvious or latent immunodeficiency; fever, if any, is observed subordinate to extracerebral nocardiosis. Computerized tomography scan and conventional magnetic resonance (MR) scan show lesions with a necrotic core and multilobed thick walls enhancing after injection of gadolinium or iodine. Abscesses are mainly located in the brain stem, basal ganglia and cerebral cortex of the frontal, parietal and occipital lobes; cerebellar and spinal locations are uncommon. MR diffusion-weighted imaging with calculation of apparent diffusion coefficient and proton MR spectroscopy can provide additional data for accurate differential diagnosis between abscess and other necrotic lesions, such as tumor and cyst formations. Bacteriological identification has progressed with advances in molecular microbiology: 16S rRNA sequencing, allowing a more rapid routine identification of Nocardia strains from clinical samples. Clinical management of patients with a Nocardia brain abscess relies upon early use of intravenous antibiotics adapted to the strains identified and their susceptibility. Most Nocardia strains display susceptibility to cotrimoxazol, amikacin and linezolid, but develop beta-lactamase activity. Early pus samples, obtained by biopsy or surgical resection, are needed to establish a certain bacteriological diagnosis and initiate appropriate intravenous antibiotics.

  4. The Effect of Metallicity on Molecular Gas and Star Formation in the Large Magellanic Cloud

    NASA Astrophysics Data System (ADS)

    Jameson, Katherine; Bolatto, A. D.; Leroy, A. K.; Wolfire, M. G.; Meixner, M.; Roman-Duval, J.; Gordon, K. D.; HERITAGE Collaboration

    2014-01-01

    The Magellanic Clouds provide the only laboratory to study the effect of metallicity on molecular gas and star formation at high resolution. We use the dust emission (Herschel 100, 160, 250, and 350 micron) to trace the total column of gas distribution and remove the HI gas leaving the molecular gas component distribution; we avoid the known biases of CO and reveal molecular gas with no bright CO emission. Relating the molecular gas to the star formation rate, traced by H-alpha and 24 micron, reveals an average molecular gas depletion time of ˜ 1 Gyr in the LMC. This is consistent with normal disk galaxies (˜ 2 Gyr; Bigiel et al. 2008, 2012) and the SMC (Bolatto et al. 2011), suggesting that metallicity does not strongly affect the galaxy-wide molecular gas star formation efficiency. We also contrast the metallicity-dependent predictions of the Ostriker, McKee, & Leroy (2011) and Krumholz, McKee, & Tumlinson (2009) models of star formation with the data.

  5. An apparent permeability model of shale gas under formation conditions

    NASA Astrophysics Data System (ADS)

    Chen, Peng; Jiang, Shan; Chen, Yan; Wang, Shanshan

    2017-08-01

    There are various types of pores in shale, mainly consisting of nanopores and micropores, causing flow regime variations and apparent permeability changes during the development of the reservoir. In this paper, a Knudsen number calculation model is proposed with the actual conditions of gas in a shale reservoir. Then, based on the distribution of pores in shale, an apparent permeability model is established using hydrodynamics, and a calculation method is put forward for the actual permeability of a reservoir. Finally, the Knudsen number model and the permeability correction coefficient model are used to analyze the flow regime and permeability correction coefficients in pores during the development of the shale gas reservoir. Results show that with a decreasing of pressure, the Knudsen number increases, the flow regime changes from continuous flow and slip flow to transition flow or free molecular flow. When the Knudsen number is Kn > 0.1, and with a further increasing of Kn, gas molecule slippage greatly intensifies and the permeability correction coefficient K app/Kd significantly increases. While the Knudsen number increases, the permeability correction coefficient significantly increases in the micropores and the small pores, but this does not appear in the macropores and the mesopores. These results can be used to guide flow regime analysis and production forecasting in shale gas reservoirs.

  6. An Introverted Starburst: Gas and SSC Formation in NGC 5253

    NASA Astrophysics Data System (ADS)

    Turner, J. L.; Beck, S. C.

    2004-06-01

    High resolution Brackett line spectroscopy with the Keck Telescope reveals relatively narrow recombination lines toward the embedded young super star cluster nebula in NGC 5253. The gas within this nebula is almost certainly gravitationally bound by the massive and compact young star cluster.

  7. Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

    SciTech Connect

    Hu, Shenyang; Burkes, Douglas E.; Lavender, Curt A.; Senor, David J.; Setyawan, Wahyu; Xu, Zhijie

    2016-07-08

    Nano-gas bubble superlattices are often observed in irradiated UMo nuclear fuels. However, the for- mation mechanism of gas bubble superlattices is not well understood. A number of physical processes may affect the gas bubble nucleation and growth; hence, the morphology of gas bubble microstructures including size and spatial distributions. In this work, a phase-field model integrating a first-passage Monte Carlo method to investigate the formation mechanism of gas bubble superlattices was devel- oped. Six physical processes are taken into account in the model: 1) heterogeneous generation of gas atoms, vacancies, and interstitials informed from atomistic simulations; 2) one-dimensional (1-D) migration of interstitials; 3) irradiation-induced dissolution of gas atoms; 4) recombination between vacancies and interstitials; 5) elastic interaction; and 6) heterogeneous nucleation of gas bubbles. We found that the elastic interaction doesn’t cause the gas bubble alignment, and fast 1-D migration of interstitials along $\\langle$110$\\rangle$ directions in the body-centered cubic U matrix causes the gas bubble alignment along $\\langle$110$\\rangle$ directions. It implies that 1-D interstitial migration along [110] direction should be the primary mechanism of a fcc gas bubble superlattice which is observed in bcc UMo alloys. Simulations also show that fission rates, saturated gas concentration, and elastic interaction all affect the morphology of gas bubble microstructures.

  8. Coral reef formation theory may apply to oil, gas exploration

    SciTech Connect

    Not Available

    1990-12-10

    This paper reports a coral reef formation theory that has implications for hydrocarbon exploration. The theory states that many coral reefs and carbonate buildups from at and are dependent upon nutrient rich fluids seeping through the seabed.

  9. Gas Dynamics and the Formation of Galaxies and Quasars

    NASA Technical Reports Server (NTRS)

    Loeb, Abraham (Principal Investigator)

    1997-01-01

    Below we enclose a list of papers that were written during 1995/96. These papers focus on structure formation in the universe at high redshifts, and accomplish various aspects of the research goals of this grant.

  10. Direct formation of supermassive black holes via multi-scale gas inflows in galaxy mergers.

    PubMed

    Mayer, L; Kazantzidis, S; Escala, A; Callegari, S

    2010-08-26

    Observations of distant quasars indicate that supermassive black holes of billions of solar masses already existed less than a billion years after the Big Bang. Models in which the 'seeds' of such black holes form by the collapse of primordial metal-free stars cannot explain the rapid appearance of these supermassive black holes because gas accretion is not sufficiently efficient. Alternatively, these black holes may form by direct collapse of gas within isolated protogalaxies, but current models require idealized conditions, such as metal-free gas, to prevent cooling and star formation from consuming the gas reservoir. Here we report simulations showing that mergers between massive protogalaxies naturally produce the conditions for direct collapse into a supermassive black hole with no need to suppress cooling and star formation. Merger-driven gas inflows give rise to an unstable, massive nuclear gas disk of a few billion solar masses, which funnels more than 10(8) solar masses of gas to a sub-parsec-scale gas cloud in only 100,000 years. The cloud undergoes gravitational collapse, which eventually leads to the formation of a massive black hole. The black hole can subsequently grow to a billion solar masses on timescales of about 10(8) years by accreting gas from the surrounding disk.

  11. [Immunological status of patients with amebic hepatic abscess].

    PubMed

    Canto Solís, A; Miranda Feria, A J; Medina Martinez, J; Teran Ortíz, L A; Suárez Sánchez, F

    1975-01-01

    The authors studied 10 cases of amoebic hepatic abscess documented by clinical evidence and confirmed by laboratory tests, liver scan and a good response to treatment. The immunological state of the patients was determined by protein electrophoresis, immunoelectrophoresis, counter-immunoelectrophoresis, radial immunodiffusion and roset formation for T and B lymphocytes. It is concluded that the alterations of cellular and humoral immunity is evident in cases of amoebic hepatic abscess; this alterations are more clear in the acute form of the illness and the immunological deficiency is more significant in the celular immunity.

  12. Bubble formation during horizontal gas injection into downward-flowing liquid

    NASA Astrophysics Data System (ADS)

    Bai, Hua; Thomas, Brian G.

    2001-12-01

    Bubble formation during gas injection into turbulent downward-flowing water is studied using high-speed videos and mathematical models. The bubble size is determined during the initial stages of injection and is very important to turbulent multiphase flow in molten-metal processes. The effects of liquid velocity, gas-injection flow rate, injection hole diameter, and gas composition on the initial bubble-formation behavior have been investigated. Specifically, the bubble-shape evolution, contact angles, size, size range, and formation mode are measured. The bubble size is found to increase with increasing gas-injection flow rate and decreasing liquid velocity and is relatively independent of the gas injection hole size and gas composition. Bubble formation occurs in one of four different modes, depending on the liquid velocity and gas flow rate. Uniform-sized spherical bubbles form and detach from the gas injection hole in mode I for a low liquid speed and small gas flow rate. Modes III and IV occur for high-velocity liquid flows, where the injected gas elongates down along the wall and breaks up into uneven-sized bubbles. An analytical two-stage model is developed to predict the average bubble size, based on realistic force balances, and shows good agreement with measurements. Preliminary results of numerical simulations of bubble formation using a volume-of-fluid (VOF) model qualitatively match experimental observations, but more work is needed to reach a quantitative match. The analytical model is then used to estimate the size of the argon bubbles expected in liquid steel in tundish nozzles for conditions typical of continuous casting with a slide gate. The average argon bubble sizes generated in liquid steel are predicted to be larger than air bubbles in water for the same flow conditions. However, the differences lessen with increasing liquid velocity.

  13. Potential for deep basin-centered gas accumulation in Travis Peak (Hosston) Formation, Gulf Coastal Basin

    USGS Publications Warehouse

    Bartberger, Charles E.; Dyman, Thaddeus S.; Condon, Steven M.

    2003-01-01

    The potential of Lower Cretaceous sandstones of the Travis Peak Formation in the northern Gulf Coast Basin to harbor a basin-centered gas accumulation was evaluated by examining (1) the depositional and diagenetic history and reservoir properties of Travis Peak sandstones, (2) the presence and quality of source rocks for generating gas, (3) the burial and thermal history of source rocks and time of gas generation and migration relative to tectonic development of Travis Peak traps, (4) gas and water recoveries from drill-stem and formation tests, (5) the distribution of abnormal pressures based on shut-in-pressure data, and (6) the presence or absence of gas-water contacts associated with gas accumulations in Travis Peak sandstones. The Travis Peak Formation (and correlative Hosston Formation) is a basinward-thickening wedge of terrigenous clastic sedimentary rocks that underlies the northern Gulf Coast Basin from eastern Texas across northern Louisiana to southern Mississippi. Clastic infl ux was focused in two main fl uvial-deltaic depocenters?one located in northeastern Texas and the other in southeastern Mississippi and northeastern Louisiana. Across the main hydrocarbon-productive trend in eastern Texas and northern Louisiana, the Travis Peak Formation is about 2,000 ft thick. Most Travis Peak hydrocarbon production in eastern Texas comes from drilling depths between 6,000 and 10,000 ft. Signifi cant decrease in porosity and permeability occurs through that depth interval. Above 8,000-ft drilling depth in eastern Texas, Travis Peak sandstone matrix permeabilities often are signifi cantly higher than the 0.1-millidarcy (mD) cutoff that characterizes tight-gas reservoirs. Below 8,000 ft, matrix permeability of Travis Peak sandstones is low because of pervasive quartz cementation, but abundant natural fractures impart signifi cant fracture permeability. Although pressure data within the middle and lower Travis Peak Formation are limited in eastern Texas

  14. Formation of induced surface heterogeneity in a rarefied gas medium

    SciTech Connect

    Borisov, S.F.; Kochnev, A.A.; Kulev, A.N.; Shestakov, A.M.; Shveikin, G.P.

    1987-11-01

    Induced surface heterogeneity caused by gas adsorption exerts a substantial effect on the surface properties of a solid. In this work, in order to study the dynamics of metal surface coverage in vacuum caused by adsorption of components of the residual gas medium, an experimental approach has been realized that is based on a combination of the spark method with Auger electron spectroscopy of the surface. The choice of thin tungsten filament as the object of investigation was due to the wide use of similar samples in thermal experiments, particularly in measuring the accomodation coefficient of the energy of gaseous molecules. Preliminary thermal desorption experiments at approx. 300/sup 0/K established that mainly H/sub 2/ and N/sub 2/ were adsorbed on the surface. Adsorption of H/sub 2/O, CH/sub 4/, CO/sub 2/, and D/sub 2/ constituted a substantially smaller fraction.

  15. Splenic abscess owing to cancer at the splenic flexure

    PubMed Central

    Awotar, Gavish K.; Luo, Fuwen; Zhao, Zhengdong; Guan, Guoxin; Ning, Shili; Ren, Jinshuai; Liu, Yaqing; Wang, Guangzhi; Liu, Pixu

    2016-01-01

    Abstract Background: The cancer of the splenic flexure of the colon is a rare medical entity with severe morbidity because of its insidious onset. Methods: We present the case of a 59-year-old male patient with dull left upper quadrant pain, leukocytosis, and anemia. A splenic abscess described as an air-fluid level with splenocolic fistula was found on CT scan imaging. Surgery was done for splenic pus drainage. He was again admitted 2 months later for intestinal obstruction. Results: An exploratory laparotomy showed multiple hard, gray liver nodules as well as a hard mass in the small bowel. Owing to extensive adhesions and a late stage of cancer involvement, the splenic flexure tumor was not resected. A loop transverse colostomy was done and a ColoplastTM Colostomy bag placed. We also reviewed the literature-linking colon cancer and splenic abscess with specific attention to the carcinoma of the splenic flexure. As the latter invades through the spleen matter, there is the creation of a splenocolic fistula, which allows the migration of normal gut flora into the spleen. This leads to the formation of the splenic abscess. Conclusion: This is the 13th case report pertaining to invading colonic cancer causing a splenic abscess. Although the treatment for splenic abscesses is shifting from splenectomy to image-guided percutaneous pus drainage, the few reported cases make the proper management of such complication still unclear. PMID:27661050

  16. Brain abscess in hepatopulmonary syndrome associated with biliary atresia.

    PubMed

    Morita, Keiichi; Fukuzawa, Hiroaki; Maeda, Kosaku

    2015-12-01

    The first-choice therapy for biliary atresia (BA) is Kasai hepatoportoenterostomy, which has been shown to greatly improve outcome. Various long-term complications, however, such as portal hypertension and hepatopulmonary syndrome (HPS), can occur in patients with native liver. A rare case of brain abscess in an 11-year-old girl with HPS associated with BA is reported. The patient underwent hepatoportoenterostomy for BA at 53 days of age, with resolution of hyperbilirubinemia. At 10 years of age, she was diagnosed with severe HPS with right-to-left shunting, and preparations for liver transplantation proceeded. Three months after the diagnosis, she had a right parietal brain abscess. Given that the brain abscess enlarged in size, surgical drainage of the brain abscess was performed. The postoperative course was uneventful, but a slight left hemiplegia remained at discharge. The presumed mechanism of abscess formation in HPS may be right-to-left bacterial transit through intrapulmonary vascular dilatations and/or arteriovenous fistulae. © 2015 Japan Pediatric Society.

  17. Gas-oil fluids in the formation of travertines in the Baikal rift zone

    NASA Astrophysics Data System (ADS)

    Tatarinov, A. A.; Yalovik, L. I.; Shumilova, T. G.; Kanakin, S. V.

    2016-07-01

    Active participation of gas-oil fluids in the processes of mineral formation and petrogenesis in travertines of the Arshan and Garga hot springs is substantiated. The parageneses of the products of pyrolytic decomposition and oxidation of the gas-oil components of hydrothermal fluids (amorphous bitumen, graphite-like CM, and graphite) with different genetic groups of minerals crystallized in a wide range of P-T conditions were established. Travertines of the Baikal rift zone were formed from multicomponent hydrous-gas-oil fluids by the following basic mechanisms of mineral formation: chemogenic, biogenic, cavitation, fluid pyrometamorphism, and pyrolysis.

  18. Preliminary formation analysis for compressed air energy storage in depleted natural gas reservoirs :

    SciTech Connect

    Gardner, William Payton

    2013-06-01

    The purpose of this study is to develop an engineering and operational understanding of CAES performance for a depleted natural gas reservoir by evaluation of relative permeability effects of air, water and natural gas in depleted natural gas reservoirs as a reservoir is initially depleted, an air bubble is created, and as air is initially cycled. The composition of produced gases will be evaluated as the three phase flow of methane, nitrogen and brine are modeled. The effects of a methane gas phase on the relative permeability of air in a formation are investigated and the composition of the produced fluid, which consists primarily of the amount of natural gas in the produced air are determined. Simulations of compressed air energy storage (CAES) in depleted natural gas reservoirs were carried out to assess the effect of formation permeability on the design of a simple CAES system. The injection of N2 (as a proxy to air), and the extraction of the resulting gas mixture in a depleted natural gas reservoir were modeled using the TOUGH2 reservoir simulator with the EOS7c equation of state. The optimal borehole spacing was determined as a function of the formation scale intrinsic permeability. Natural gas reservoir results are similar to those for an aquifer. Borehole spacing is dependent upon the intrinsic permeability of the formation. Higher permeability allows increased injection and extraction rates which is equivalent to more power per borehole for a given screen length. The number of boreholes per 100 MW for a given intrinsic permeability in a depleted natural gas reservoir is essentially identical to that determined for a simple aquifer of identical properties. During bubble formation methane is displaced and a sharp N2methane boundary is formed with an almost pure N2 gas phase in the bubble near the borehole. During cycling mixing of methane and air occurs along the boundary as the air bubble boundary moves. The extracted gas mixture changes as a

  19. Aseptic lung and liver abscesses: a diagnostic challenge.

    PubMed

    Yildiz, Halil; Munting, Aline; Komuta, Mina; Danse, Etienne; Lefebvre, Chantal

    2017-08-01

    A 67-year-old man known with systemic sarcoidosis was admitted to the department of internal medicine because of cough and chest pain for several weeks. Thoracic tomodensitometry demonstrated multiple pulmonary nodules. Biopsies revealed features compatible with abscesses. Cultures and serologic tests were negative and the patient was successfully treated with prednisone. Three years later, a thoraco-abdominal tomodensitometry showed a relapse in the lung and also the apparition of similar lesions in the liver. Blood test revealed elevated CRP level at 40 mg/L and mild cholestasis. Biopsies of the liver excluded neoplastic or infectious diseases and showed inflammatory granulation tissue with abscess formation. A diagnosis of sarcoidosis-associated aseptic abscesses syndrome was then made, which was successfully treated with corticosteroids.

  20. A Case of Orbital Abscess following Porous Orbital Implant Infection

    PubMed Central

    Hong, Seung Woo; Paik, Ji-Sun; Kim, So-Youl

    2006-01-01

    Purpose We present a case of orbital abscess following porous orbital implant infection in a 73-year-old woman with rheumatoid arthritis. Methods Just one month after a seemingly uncomplicated enucleation and porous polyethylene (Medpor®) orbital implant surgery, implant exposure developed with profuse pus discharge. The patient was unresponsive to implant removal and MRI confirmed the presence of an orbital pus pocket. Despite extirpation of the four rectus muscles, inflammatory granulation debridement and abscess drainage, another new pus pocket developed. Results After partial orbital exenteration, the wound finally healed well without any additional abscess formation. Conclusions A patient who has risk factors for delayed wound healing must be examined thoroughly and extreme care such as exenteration must be taken if there is persistent infection. PMID:17302210

  1. Mutations in the major gas vesicle protein GvpA and impacts on gas vesicle formation in Haloferax volcanii.

    PubMed

    Knitsch, Regine; Schneefeld, Marie; Weitzel, Kerstin; Pfeifer, Felicitas

    2017-09-12

    Gas vesicles are proteinaceous, gas-filled nanostructures produced by some bacteria and archaea. The hydrophobic major structural protein GvpA forms the ribbed gas vesicle wall. An in-silico 3D-model of GvpA of the predicted coil-α1-β1-β2-α2-coil structure is available and implies that the two β-chains constitute the hydrophobic interior surface of the gas vesicle wall. To test the importance of individual amino acids in GvpA we performed 85 single substitutions and analyzed these variants in Haloferax volcanii ΔA + Amut transformants for their ability to form gas vesicles (Vac(+) phenotype). In most cases, an alanine substitution of a non-polar residue did not abolish gas vesicle formation, but the replacement of single non-polar by charged residues in β1 or β2 resulted in Vac(-) transformants. A replacement of residues near the β-turn altered the spindle-shape to a cylindrical morphology of the gas vesicles. Vac(-) transformants were also obtained with alanine substitutions of charged residues of helix α1 suggesting that these amino acids form salt-bridges with another GvpA monomer. In helix α2, only the alanine substitution of His53 or Tyr54, led to Vac(-) transformants, whereas most other substitutions had no effect. We discuss our results in respect to the GvpA structure and data available from solid-state NMR. © 2017 John Wiley & Sons Ltd.

  2. Evaluation of the geological relationships to gas hydrate formation and stability

    SciTech Connect

    Krason, J.; Finley, P.

    1988-01-01

    The summaries of regional basin analyses document that potentially economic accumulations of gas hydrates can be formed in both active and passive margin settings. The principal requirement for gas hydrate formation in either setting is abundant methane. Passive margin sediments with high sedimentation rates and sufficient sedimentary organic carbon can generate large quantities of biogenic methane for hydrate formation. Similarly, active margin locations near a terrigenous sediment source can also have high methane generation potential due to rapid burial of adequate amounts of sedimentary organic matter. Many active margins with evidence of gas hydrate presence correspond to areas subject to upwelling. Upwelling currents can enhance methane generation by increasing primary productivity and thus sedimentary organic carbon. Structural deformation of the marginal sediments at both active and passive sites can enhance gas hydrate formation by providing pathways for migration of both biogenic and thermogenic gas to the shallow gas hydrate stability zone. Additionally, conventional hydrocarbon traps may initially concentrate sufficient amounts of hydrocarbons for subsequent gas hydrate formation.

  3. Recoverable natural gas reserves from Jurassic Norphlet Formation, Alabama coastal waters

    SciTech Connect

    Mancini, E.A.; Mink, R.M.; Bearden, B.L.; Hamilton, R.P.

    1987-09-01

    To date, 11 Norphlet gas fields have been established in offshore Alabama. These fields are part of a deep Jurassic gas trend that extends across southern Mississippi and Alabama into the Gulf of Mexico. Recoverable gas reserves of 4.9-8.1 tcf are estimated for the Norphlet Formation in Alabama's coastal waters. Proven gas reserves are estimated to be 3.7-4.6 tcf and potential reserves are estimated to be 1.2-3.5 tcf. The natural gas is trapped in a series of generally east-west-trending salt anticlines. The mechanism of structure formation appears to be salt flowage that has formed broad, low-relief anticlines, most of which are faulted, and many of which are related to small-scale growth faults. Salt movement is the critical factor in the formation of these petroleum traps. The primary Norphlet reservoir lithofacies are eolian dune and interdune sandstones that range in thickness from 140 to over 600 ft in Alabama's coastal waters. Gas pay can exceed 280 ft in thickness. Porosity is principally secondary, developed as a result of decementation and grain dissolution. Jurassic Smackover algal carbonate mudstones were the main source for the Norphlet hydrocarbons. The seal for the gas is the nonpermeable upper portion of the Norphlet Formation. The overlying lower Smackover carbonates are also nonpermeable and may serve as part of the seal.

  4. [Amoebic liver abscess: echographic aspects].

    PubMed

    Niang, H E; Ka, M M; Badiane, M; Ba, A; Konde, L; Lamouche, P

    1994-01-01

    Amoebic liver abscess is the most frequent location of the extra-intestine amibiasis with an epidemio-endemic repartition in our areas. We are reporting in this study the main echographic patterns that can be found. 117 documents were collected and studied between 1982 and 1988 in the main hospitals of Dakar (SENEGAL). Most of the patients were young, the range of age being between 25 and 55 years old and 83% of them, were male. The diagnosis of the amoebic liver abscess was evocated on the basis of the following clinical and biological symptoms: 54.38% of painful haetomegaly, 42.10% of pleuro-pulmonary and digestive signs, 3.50% of long lasting isolated fever, non specific biological sign of inflammation, 74.57% of positive hemaglutination test. An echographic test was performed before the anti-parasitic treatment with an echotomograph PHILIPS SDR 1500 in real time using a probe of 3 MHZ. The amoebic abscess of liver was detected by the echography in all cases. The unique abscess (83.10%) was the most frequent form. It was localized in the right liver (64%) and had an heterogeneous echostructure (55.70%). The hypo-echogeneous form (36.50%) was the earlier stage of the collecting abscess. The liquid form (07.80%) was observed in the latter stages of the disease. Some difficulties to determine the amoebic abscess may appear when primitive liver cancer or pyogensus abscess are present. In these cases it is necessary to analyse the liquid of ponction to be affirmative.

  5. Formation of pyrimidine dimer radical anions in the gas phase.

    PubMed

    Edtbauer, Achim; Russell, Katherine; Feketeová, Linda; Taubitz, Jörg; Mitterdorfer, Christian; Denifl, Stephan; O'Hair, Richard A J; Märk, Tilmann D; Scheier, Paul; Wille, Uta

    2009-12-21

    Crossed-beam experiments revealed that attachment of a free electron to the cyclobutane pyrimidine dimers c,s-DMT<>DMT and c,a-DMT<>DMT leads to the formation of dimer radical anions with the lifetime of at least 80 micros, thus showing that the latter are much more stable than previously believed.

  6. Production of hydrogen sulphide containing gas from underground formations

    SciTech Connect

    Delude, S.G.; Luinstra, E.A.

    1988-12-06

    This patent describes a process for the production of at least a gaseous product containing a substantial amount of hydrogen sulphide via a bore-hole from an underground formation containing besides the hydrogen sulphide at least elemental sulphur, comprising (a) injection of a liquid substantially consisting of hydrocarbons into the bore-hole or into the underground formation near to the end of the bore-hole; (b) producing a gaseous and a liquid fraction from the underground formation; (c) separating the gaseous fraction from the liquid fraction (d) if necessary, separating an aqueous fraction of the produced liquid fraction from the hydrocarbons-containing fraction; (e) heating the hydrocarbons-containing fraction in order to remove elemental sulphur by conversion to hydrogen sulphide in the presence of a catalyst comprising sulphides of one of more metals from Group VIB and/or Group VIII of the Periodic Table of Elements deposited on a support of alumina, silica or silica alumina; and (f) reinjection of at least a part of the thus treated hydrocarbons-containing fraction into the bore-hole or into the underground formation near to the end of the bore-hole as described hereinbefore.

  7. Gas in Debris Disks and the Volatiles of Terrestrial Planet Formation

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc

    2010-01-01

    Debris disks are a kind of protoplanetary disk that likely corresponds to the epoch of terrestrial planet and outer planet formation. Previously pictured to be gas-free, some debris disks are now revealing gas components, sometimes with strikingly non-solar abundance patterns. Understanding the nature and distribution of this gas may eventually help us understand the origin of volatiles on the Earth, the carbon depletion of the asteroids, and even the origin of life. I'll describe what we know about these systems observationally, some of the leading hypotheses about the sources and sinks of the gas, and how these new astronomical discoveries may bear on solar-system science.

  8. Gas in Debris Disks and the Volatiles of Terrestrial Planet Formation

    NASA Technical Reports Server (NTRS)

    Kuchner, Marc

    2010-01-01

    Debris disks are a kind of protoplanetary disk that likely corresponds to the epoch of terrestrial planet and outer planet formation. Previously pictured to be gas-free, some debris disks are now revealing gas components, sometimes with strikingly non-solar abundance patterns. Understanding the nature and distribution of this gas may eventually help us understand the origin of volatiles on the Earth, the carbon depletion of the asteroids, and even the origin of life. I'll describe what we know about these systems observationally, some of the leading hypotheses about the sources and sinks of the gas, and how these new astronomical discoveries may bear on solar-system science.

  9. A study of the gas-star formation relation over cosmic time

    NASA Astrophysics Data System (ADS)

    Genzel, R.; Tacconi, L. J.; Gracia-Carpio, J.; Sternberg, A.; Cooper, M. C.; Shapiro, K.; Bolatto, A.; Bouché, N.; Bournaud, F.; Burkert, A.; Combes, F.; Comerford, J.; Cox, P.; Davis, M.; Schreiber, N. M. Förster; Garcia-Burillo, S.; Lutz, D.; Naab, T.; Neri, R.; Omont, A.; Shapley, A.; Weiner, B.

    2010-10-01

    We use the first systematic data sets of CO molecular line emission in z ~ 1-3 normal star-forming galaxies (SFGs) for a comparison of the dependence of galaxy-averaged star formation rates on molecular gas masses at low and high redshifts, and in different galactic environments. Although the current high-z samples are still small and biased towards the luminous and massive tail of the actively star-forming `main-sequence', a fairly clear picture is emerging. Independent of whether galaxy-integrated quantities or surface densities are considered, low- and high-z SFG populations appear to follow similar molecular gas-star formation relations with slopes 1.1 to 1.2, over three orders of magnitude in gas mass or surface density. The gas-depletion time-scale in these SFGs grows from 0.5 Gyr at z ~ 2 to 1.5 Gyr at z ~ 0. The average corresponds to a fairly low star formation efficiency of 2 per cent per dynamical time. Because star formation depletion times are significantly smaller than the Hubble time at all redshifts sampled, star formation rates and gas fractions are set by the balance between gas accretion from the halo and stellar feedback. In contrast, very luminous and ultraluminous, gas-rich major mergers at both low and high z produce on average four to 10 times more far-infrared luminosity per unit gas mass. We show that only some fraction of this difference can be explained by uncertainties in gas mass or luminosity estimators; much of it must be intrinsic. A possible explanation is a top-heavy stellar mass function in the merging systems but the most likely interpretation is that the star formation relation is driven by global dynamical effects. For a given mass, the more compact merger systems produce stars more rapidly because their gas clouds are more compressed with shorter dynamical times, so that they churn more quickly through the available gas reservoir than the typical normal disc galaxies. When the dependence on galactic dynamical time-scale is

  10. [Meningitis and brain abscess caused by Streptococcus intermedius in a patient infected with HIV-1].

    PubMed

    Vallalta Morales, M; Solaz Moreno, E; Lacruz Rodrigo, J; Salavert Lletí, M; Silla Burdalo, G; Pérez-Bellés, C

    2005-06-01

    Streptococcus milleri group have been recognized as an important pathogens for abscess formation in various organs. Streptococci other than Streptococcus pneumoniae are a rare cause of bacterial meningitis in adults and can be associated with the presence of an undiagnosed brain abscess. Brain abscess is a focal collection within the brain parenchyma which can arise as a complication of a variety of infections. The most common etiologic organisms in clinical series have been microaerophilic streptococci and anaerobic bacteria. Although intracranial mass lesions that occur as a result of infection have commonly been reported in patients infected with the human immunodeficiency virus, brain abscess due to the common bacterial pathogens are rarely described in HIV infected patients and Toxoplasma gondii is the organism most frequently isolated from stereotactic brain biopsy in these patients. We report a patient with both HIV-1 infection and streptococcal meningitis secondary to brain abscess caused by S. intermedius.

  11. Surfactants from the gas phase may promote cloud droplet formation.

    PubMed

    Sareen, Neha; Schwier, Allison N; Lathem, Terry L; Nenes, Athanasios; McNeill, V Faye

    2013-02-19

    Clouds, a key component of the climate system, form when water vapor condenses upon atmospheric particulates termed cloud condensation nuclei (CCN). Variations in CCN concentrations can profoundly impact cloud properties, with important effects on local and global climate. Organic matter constitutes a significant fraction of tropospheric aerosol mass, and can influence CCN activity by depressing surface tension, contributing solute, and influencing droplet activation kinetics by forming a barrier to water uptake. We present direct evidence that two ubiquitous atmospheric trace gases, methylglyoxal (MG) and acetaldehyde, known to be surface-active, can enhance aerosol CCN activity upon uptake. This effect is demonstrated by exposing acidified ammonium sulfate particles to 250 parts per billion (ppb) or 8 ppb gas-phase MG and/or acetaldehyde in an aerosol reaction chamber for up to 5 h. For the more atmospherically relevant experiments, i.e., the 8-ppb organic precursor concentrations, significant enhancements in CCN activity, up to 7.5% reduction in critical dry diameter for activation, are observed over a timescale of hours, without any detectable limitation in activation kinetics. This reduction in critical diameter enhances the apparent particle hygroscopicity up to 26%, which for ambient aerosol would lead to cloud droplet number concentration increases of 8-10% on average. The observed enhancements exceed what would be expected based on Köhler theory and bulk properties. Therefore, the effect may be attributed to the adsorption of MG and acetaldehyde to the gas-aerosol interface, leading to surface tension depression of the aerosol. We conclude that gas-phase surfactants may enhance CCN activity in the atmosphere.

  12. Shale gas reservoir characteristics of Ordovician-Silurian formations in the central Yangtze area, China

    NASA Astrophysics Data System (ADS)

    Shan, Chang'an; Zhang, Tingshan; Wei, Yong; Zhang, Zhao

    2017-03-01

    The characteristics of a shale gas reservoir and the potential of a shale gas resource of Ordovician-Silurian age in the north of the central Yangtze area were determined. Core samples from three wells in the study area were subjected to thin-section examination, scanning electron microscopy, nuclear magnetic resonance testing, X-ray diffraction mineral analysis, total organic carbon (TOC) testing, maturity testing, gas-bearing analysis, and gas component and isothermal adsorption experiments. A favorable segment of the gas shale reservoir was found in both the Wufeng Formation and the lower part of the Longmaxi Formation; these formations were formed from the late Katian to early Rhuddanian. The high-quality shale layers in wells J1, J2, and J3 featured thicknesses of 54.88 m, 48.49 m, and 52.00 m, respectively, and mainly comprised carbonaceous and siliceous shales. Clay and brittle minerals showed average contents of 37.5% and 62.5% (48.9% quartz), respectively. The shale exhibited type II1 kerogens with a vitrinite reflectance ranging from 1.94% to 3.51%. TOC contents of 0.22%-6.05% (average, 2.39%) were also observed. The reservoir spaces mainly included micropores and microfractures and were characterized by low porosity and permeability. Well J3 showed generally high gas contents, i.e., 1.12-3.16 m3/t (average 2.15 m3/t), and its gas was primarily methane. The relatively thick black shale reservoir featured high TOC content, high organic material maturity, high brittle mineral content, high gas content, low porosity, and low permeability. Shale gas adsorption was positively correlated with TOC content and organic maturity, weakly positive correlated with quartz content, and weakly negatively correlated with clay content. Therefore, the Wufeng and Longmaxi formations in the north of the central Yangtze area have a good potential for shale gas exploration.

  13. Star Formation and Gas Densities in the Dwarf Irregular Galaxy Sextans A

    NASA Astrophysics Data System (ADS)

    Plummer, Julia D.; Hunter, Deidre A.

    1995-12-01

    As a step in understanding the process of star formation in irregular galaxies, we have analysed the irregular galaxy Sextans A. Irregular galaxies provide star-forming systems that are unperturbed by spiral density waves. Sextans A is a tiny galaxy, 1.3 Mpc distant, just beyond the dynamic boundary of the Local Group. We studied the star formation properties of this galaxy using UBV and Hα images. Stars are not currently forming in the center of this galaxy, though they have in the past. The current star formation is in clumps in the outer parts of the galaxy and is not evenly distributed. The total Hα luminosity found for Sextans A is 9 x 10(38) erg/s, which corresponds to a star formation rate of 6 x 10(-3) Mmathordsun /yr for standard assumptions. The rate per unit area, within the Holmberg radius, is 6 x 10(-10) Mmathordsun /yr/pc(2) . Skillman et al. (1988) derived a total HI mass of 6 x 10(7) Mmathordsun . At its present rate, Sextans A will use up all of its gas in 12 x 10(9) yr, including the He contribution. We have also compared the star formation and gas density in Sextans A to critical gas surface density models (Toomre 1964, Quirk 1972, Kennicutt 1988). We used a published rotation curve to calculate the critical gas density necessary for the instabilities that produce star-forming clouds (Skillman et al. 1988). The ratio of observed to critical gas density is low in Sextans A, at the low end of values found by Kennicutt (1988) for spiral galaxies. The current star formation is located in the region of the galaxy with higher radially averaged observed gas densities relative to the critical density. This suggests that Sextans A has a difficult time forming gas clouds, resulting in an observed low star formation rate. This research was funded by the REU program at Northern Arizona University.

  14. On the temperature and gas composition in the region of comet formation

    NASA Astrophysics Data System (ADS)

    Bar-Nun, A.; Kleinfeld, I.

    1989-08-01

    The gas composition and temperature in the region of Comet Halley's formation are estimated on the basis of Giotto and Vega spacecraft results, in conjunction with an experimental study of gas-mixture trapping in amorphous water ice. A CO/CH4 ratio of the order of 100, and temperature about 48 K, are inferred for the case of Halley formation in the solar nebula through water vapor condensation in the presence of gas. This formation temperature, which implies that the ice was in amorphous form, is noted to be close to the temperatures observed in circumstellar dust shells by IRAS; it also lends support to the suggestion that short-period comets were formed outside the planet-formation region.

  15. Molecular Gas and Star-formation in Low Surface Brightness Galaxies

    NASA Astrophysics Data System (ADS)

    Cao, Tian-Wen; Wu, Hong; Du, Wei; Lei, Feng-Jie; Zhu, Ming; Wouterloot, Jan; Parsons, Harriet; Zhu, Yi-Nan; Wu, Chao-Jian; Yang, Fan; Cao, Chen; Zhou, Zhi-Min; He, Min; Jin, Jun-Jie; Wicker, James E.

    2017-09-01

    We have obtained CO(J = 2‑1) spectra of nine face-on low surface brightness galaxies using the JCMT 15 m telescope and observed Hα images using the 2.16 m telescope of NAOC. As no CO has been detected, only upper limits on the H2 masses are given. The upper limits of total molecular hydrogen masses are about (1.2{--}82.4)× {10}7 {M}ȯ . Their star-formation rates are mainly lower than 0.4 {M}ȯ yr‑1 and star-formation efficiencies are lower than 1.364× {10}-10 yr‑1. Our results show that the absence of molecular gas content is the direct reason for the low star-formation rate. The low star-formation efficiency probably resulted from the low efficiency of H i gas transforming to H2 gas.

  16. Inhibition of giant-planet formation by rapid gas depletion around young stars.

    PubMed

    Zuckerman, B; Forveille, T; Kastner, J H

    1995-02-09

    Although stars form from clouds of gas and dust, there are insignificant amounts of gas around ordinary (Sun-like) stars. This suggests that hydrogen and helium, the primary constituents of planets such as Jupiter and Saturn, are not easily retained in orbit as a star matures. The gas-giant planets in the Solar System must therefore have formed rapidly. Models of their formation generally suggest that a solid core formed in < or = 10(6) yr, followed by the accretion of the massive gaseous envelope in approximately 10(7) yr (refs 1-5). But how and when the gas of the solar nebula dissipated, and how this compares with the predicted timescale of gas-giant formation, remains unclear, in part because direct observations of circumstellar gas have been made only for stars either younger or older than the critical range of 10(6)-10(7) yr (refs 8-15). Here we report observations of the molecular gas surrounding 20 stars whose ages are likely to be in this range. The gas dissipates rapidly; after a few million years the mass remaining is typically much less than the mass of Jupiter. Thus, if gas-giant planets are common in the Galaxy, they must form even more quickly than present models suggest.

  17. Tidal Tales II: Molecular Gas and Star Formation in the Tidal Tails of Minor Mergers

    NASA Astrophysics Data System (ADS)

    Knierman, Karen A.; Scowen, Paul A.; Groppi, Christopher E.

    2017-01-01

    While major mergers and their tidal debris are well studied, equal mass galaxy mergers are relatively rare compared to minor mergers (mass ratio <0.3).Minor mergers are less energetic than major mergers, but more common in the observable universe, and thus likely played a pivotal role in the formation of most large galaxies. Tidal debris regions have large amounts of neutral gas but a lower gas density and may have higher turbulence. We use star formation tracers such as young star cluster populations and H-alpha and CII emission to determine the different factors that may influence star formation in tidal debris. These tracers were compared to the reservoirs of molecular and neutral gas available for star formation to estimate the star formation efficiency (SFE). The SFR in tidal debris can reach up to 50% of the total star formation in the system. The SFE of tidal tails in minor mergers can range over orders of magnitude on both local and global scales. From the tidal debris environments in our study, this variance appears to stem from the formation conditions of the debris. Current surveys of the 2.12 micron line of molecular hydrogen, CO(1-0), and HI for 15 minor mergers, are providing a larger sample of environments to study the threshold for star formation that can inform star formation models, particularly at low densities.

  18. Numerical modeling of experimental observations on gas formation and multi-phase flow of carbon dioxide in subsurface formations

    NASA Astrophysics Data System (ADS)

    Pawar, R.; Dash, Z.; Sakaki, T.; Plampin, M. R.; Lassen, R. N.; Illangasekare, T. H.; Zyvoloski, G.

    2011-12-01

    One of the concerns related to geologic CO2 sequestration is potential leakage of CO2 and its subsequent migration to shallow groundwater resources leading to geochemical impacts. Developing approaches to monitor CO2 migration in shallow aquifer and mitigate leakage impacts will require improving our understanding of gas phase formation and multi-phase flow subsequent to CO2 leakage in shallow aquifers. We are utilizing an integrated approach combining laboratory experiments and numerical simulations to characterize the multi-phase flow of CO2 in shallow aquifers. The laboratory experiments involve a series of highly controlled experiments in which CO2 dissolved water is injected in homogeneous and heterogeneous soil columns and tanks. The experimental results are used to study the effects of soil properties, temperature, pressure gradients and heterogeneities on gas formation and migration. We utilize the Finite Element Heat and Mass (FEHM) simulator (Zyvoloski et al, 2010) to numerically model the experimental results. The numerical models capture the physics of CO2 exsolution, multi-phase fluid flow as well as sand heterogeneity. Experimental observations of pressure, temperature and gas saturations are used to develop and constrain conceptual models for CO2 gas-phase formation and multi-phase CO2 flow in porous media. This talk will provide details of development of conceptual models based on experimental observation, development of numerical models for laboratory experiments and modelling results.

  19. Galaxy Zoo and ALFALFA: atomic gas and the regulation of star formation in barred disc galaxies

    NASA Astrophysics Data System (ADS)

    Masters, Karen L.; Nichol, Robert C.; Haynes, Martha P.; Keel, William C.; Lintott, Chris; Simmons, Brooke; Skibba, Ramin; Bamford, Steven; Giovanelli, Riccardo; Schawinski, Kevin

    2012-08-01

    We study the observed correlation between atomic gas content and the likelihood of hosting a large-scale bar in a sample of 2090 disc galaxies. Such a test has never been done before on this scale. We use data on morphologies from the Galaxy Zoo project and information on the galaxies' H I content from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) blind H I survey. Our main result is that the bar fraction is significantly lower among gas-rich disc galaxies than gas-poor ones. This is not explained by known trends for more massive (stellar) and redder disc galaxies to host more bars and have lower gas fractions: we still see at fixed stellar mass a residual correlation between gas content and bar fraction. We discuss three possible causal explanations: (1) bars in disc galaxies cause atomic gas to be used up more quickly, (2) increasing the atomic gas content in a disc galaxy inhibits bar formation and (3) bar fraction and gas content are both driven by correlation with environmental effects (e.g. tidal triggering of bars, combined with strangulation removing gas). All three explanations are consistent with the observed correlations. In addition our observations suggest bars may reduce or halt star formation in the outer parts of discs by holding back the infall of external gas beyond bar co-rotation, reddening the global colours of barred disc galaxies. This suggests that secular evolution driven by the exchange of angular momentum between stars in the bar, and gas in the disc, acts as a feedback mechanism to regulate star formation in intermediate-mass disc galaxies. This publication has been made possible by the participation of more than 200 000 volunteers in the Galaxy Zoo project. Their contributions are individually acknowledged at South East Physics Network, E-mail: karen.masters@port.ac.ukEinstein fellow.

  20. Gas Dynamics and the Formation of Galaxies and Quasars

    NASA Technical Reports Server (NTRS)

    Loeb, Abraham

    1998-01-01

    This performance report lists papers that were written during 19978/98. These papers focus on structure formation in the universe at high redshifts, and accomplish various aspects of the research goals of this grant. Some of the papers included in this report are: 1) The First Stars and Quasars; 2) Direct Measurement of Cosmological Parameters from the Cosmic Deceleration of Extragalactic Objects; and 3) The Expected Rate of Gamma-Ray Burst Afterglows In Supernova Searches.

  1. Secondary brain abscess following simple renal cyst infection: a case report.

    PubMed

    Akuzawa, Nobuhiro; Osawa, Tenshi; Totsuka, Masayuki; Hatori, Takashi; Imai, Kunihiko; Kitahara, Yonosuke; Kurabayashi, Masahiko

    2014-06-16

    Escherichia coli (E. coli) is the most common causative bacteria of neonatal meningitis, but hematogenous intracranial E. coli infection is rare in adults. Moreover, intracranial abscess formation owing to E. coli, including brain abscesses and subdural empyema formation, is extremely rare. We herein present a case involving a patient with a brain abscess owing to E. coli following a simple renal cyst infection. A review of the literature is also presented. A 77-year-old Japanese woman with a history of polymyalgia rheumatica was admitted to our hospital because of persistent fever, right flank pain, and pyuria. Intravenous antibiotics were administered; however, her level of consciousness deteriorated 6 days after admission. Contrast-enhanced magnetic resonance imaging showed a brain abscess in the left occipital lobe and pyogenic ventriculitis. Enhanced abdominal computed tomography revealed a right renal cyst with heterogeneous content. Culture of urine, blood, and aspirated pus from the infected cyst revealed E. coli with identical antibiotic sensitivity in all sites, suggesting that the cyst infection and subsequent bacteremia might have caused the brain abscess. The patient recovered after a 6-week course of meropenem. The prognosis of patients with E. coli-associated intracranial abscess is usually poor. Advanced age and immunosuppression may be potent risk factors for intracranial abscess formation owing to the hematogenous spread of E. coli.

  2. Secondary brain abscess following simple renal cyst infection: a case report

    PubMed Central

    2014-01-01

    Background Escherichia coli (E. coli) is the most common causative bacteria of neonatal meningitis, but hematogenous intracranial E. coli infection is rare in adults. Moreover, intracranial abscess formation owing to E. coli, including brain abscesses and subdural empyema formation, is extremely rare. We herein present a case involving a patient with a brain abscess owing to E. coli following a simple renal cyst infection. A review of the literature is also presented. Case presentation A 77-year-old Japanese woman with a history of polymyalgia rheumatica was admitted to our hospital because of persistent fever, right flank pain, and pyuria. Intravenous antibiotics were administered; however, her level of consciousness deteriorated 6 days after admission. Contrast-enhanced magnetic resonance imaging showed a brain abscess in the left occipital lobe and pyogenic ventriculitis. Enhanced abdominal computed tomography revealed a right renal cyst with heterogeneous content. Culture of urine, blood, and aspirated pus from the infected cyst revealed E. coli with identical antibiotic sensitivity in all sites, suggesting that the cyst infection and subsequent bacteremia might have caused the brain abscess. The patient recovered after a 6-week course of meropenem. Conclusion The prognosis of patients with E. coli-associated intracranial abscess is usually poor. Advanced age and immunosuppression may be potent risk factors for intracranial abscess formation owing to the hematogenous spread of E. coli. PMID:24934996

  3. COLD MOLECULAR GAS IN MERGER REMNANTS. I. FORMATION OF MOLECULAR GAS DISKS

    SciTech Connect

    Ueda, Junko; Iono, Daisuke; Komugi, Shinya; Espada, Daniel; Hatsukade, Bunyo; Matsuda, Yuichi; Kawabe, Ryohei; Yun, Min S.; Crocker, Alison F.; Narayanan, Desika; Kaneko, Hiroyuki; Tamura, Yoichi; Wilner, David J.; Pan, Hsi-An

    2014-09-01

    We present the ≲1 kpc resolution {sup 12}CO imaging study of 37 optically selected local merger remnants using new and archival interferometric maps obtained with ALMA, CARMA, the Submillimeter Array, and the Plateau de Bure Interferometer. We supplement a sub-sample with single-dish measurements obtained at the Nobeyama Radio Observatory 45 m telescope for estimating the molecular gas mass (10{sup 7} {sup –} {sup 11} M {sub ☉}) and evaluating the missing flux of the interferometric measurements. Among the sources with robust CO detections, we find that 80% (24/30) of the sample show kinematical signatures of rotating molecular gas disks (including nuclear rings) in their velocity fields, and the sizes of these disks vary significantly from 1.1 kpc to 9.3 kpc. The size of the molecular gas disks in 54% of the sources is more compact than the K-band effective radius. These small gas disks may have formed from a past gas inflow that was triggered by a dynamical instability during a potential merging event. On the other hand, the rest (46%) of the sources have gas disks that are extended relative to the stellar component, possibly forming a late-type galaxy with a central stellar bulge. Our new compilation of observational data suggests that nuclear and extended molecular gas disks are common in the final stages of mergers. This finding is consistent with recent major-merger simulations of gas-rich progenitor disks. Finally, we suggest that some of the rotation-supported turbulent disks observed at high redshifts may result from galaxies that have experienced a recent major merger.

  4. Isotope Geochemistry of Natural Gas in Xujiahe Formation of the Upper Triassic in Sichuan Basin, China

    NASA Astrophysics Data System (ADS)

    Tao, Shizhen; Mi, Jingkui; Yang, Chun; Gao, Xiaohui; Wu, Songtao; Pang, Zhenglian; Fan, Jianwei

    2017-04-01

    Terrestrial tight sandstone gas is abundant Xujiahe(XJH) Formation in Sichuan Basin, China. Its reserve is over 0.6×1012m3. Though has such a huge reserve, origin and evolution of this tight sandstone gas haven't been studied thoroughly. This study is to clarify geochemical characteristics of gas formation and evolution in XJH Formation based on the comparative geochemical analysis of gas samples from fluid inclusions and gas fields. Experiments showed the great differences between gas in inclusions and from fields. There are low-medium maturity coal-derived tight sandstone gases in XJH Formation. Source rocks are mainly kerogen type-II2 and III, but coal series are type-III. The Ro is 0.8-1.4%. They are presently at post-mature to early high-mature stage, but the gas/oil ratio in present gas reservoirs is high. XJH reservoir rocks have large amount of gaseous hydrocarbon inclusions, few liquid hydrocarbon inclusions, indicating coal series type generates mainly gas (Dai et al., 1997; 2012). XJH natural gas is dominated by methane, with higher concentration of heavier C2+ hydrocarbons, belonging to kerogen-degraded gas. The gas dryness ratios are normally less than 0.95, mainly wet gas. The content of methane in the inclusions is low, rather lower for those of C2+ hydrocarbons, while that of non-hydrocarbons (CO2) is higher. Isotopic features show that tight sandstone gas of XJH Formation is typical coal-derived gas. The gas δ13C1 ranges from -45.5‰ to -36.5‰ and δ13C2 from -30‰ to -25‰.The δ13C1 and δ13C2 in fluid inclusions are similar, but mostly slightly heavier, with a δ13C1 of -36‰ -45‰ and δ13C2 of -24.8‰ -28.1‰, characterized as coal-type gas. The δ13CCO2 of gas from fields ranges from -15.6‰ to -5.6‰, and that of inclusions is lighter, ranging from -16.6‰ to -9‰, which is organic origin. The CO2 captured in the inclusions in a relatively closed system, characterizing as heavier carbon isotopic composition for alkane gas and

  5. Molecular Gas and Star Formation in Local Early-type Galaxies

    NASA Astrophysics Data System (ADS)

    Bureau, M.; Davis, T. A.; Alatalo, K.; Crocker, A. F.; Blitz, L.; Young, L. M.; Combes, F.; Bois, M.; Bournaud, F.; Cappellari, M.; Davies, R. L.; de Zeeuw, P. T.; Duc, P.-A.; Emsellem, E.; Khochfar, S.; Krajnović, D.; Kuntschner, H.; Lablanche, P.-Y.; McDermid, R. M.; Morganti, R.; Naab, T.; Oosterloo, T.; Sarzi, M.; Scott, N.; Serra, P.; Weijmans, A.

    2011-12-01

    The molecular gas content of local early-type galaxies is constrained and discussed in relation to their evolution. First, as part of the ATLAS3D survey, we present the first complete, large (260 objects), volume-limited single-dish survey of CO in normal local early-type galaxies. We find a surprisingly high detection rate of 22%, independent of luminosity and at best weakly dependent on environment. Second, the extent of the molecular gas is constrained with CO synthesis imaging, and a variety of morphologies is revealed. The kinematics of the molecular gas and stars are often misaligned, implying an external gas origin in over a third of the systems, although this behaviour is drastically diffferent between field and cluster environments. Third, many objects appear to be in the process of forming regular kpc-size decoupled disks, and a star formation sequence can be sketched by piecing together multi-wavelength information on the molecular gas, current star formation, and young stars. Last, early-type galaxies do not seem to systematically obey all our usual prejudices regarding star formation, following the standard Schmidt-Kennicutt law but not the far infrared-radio correlation. This may suggest a greater diversity in star formation processes than observed in disk galaxies. Using multiple molecular tracers, we are thus starting to probe the physical conditions of the cold gas in early-types.

  6. Gas Stripping, Turbulence, and Wake Formation in Cluster Mergers

    NASA Astrophysics Data System (ADS)

    Ricker, P. M.; Sarazin, C. L.; Kempner, J. C.; Calder, A. C.; Dursi, L. J.; Fryxell, B.; Lamb, D. Q.; Olson, K.; Rosner, R.; Timmes, F. X.; Truran, J. W.; Tufo, H.; Zingale, M.

    2001-12-01

    We present results from high-resolution (sub-kpc) hydro + dark matter simulations of the interaction of subclusters with the intracluster medium during the initial stages of a galaxy cluster merger. Using the adaptive-mesh code FLASH, we study the development of fluid instabilities along the contact surface and in the wake produced by this interaction. We examine the role of shock waves and instability-induced turbulence in the stripping of gas from the dense subcluster core. We discuss the observability of merger-induced turbulence, and we compare our results to the observed clusters Abell 85 and Abell 3667. This research has been supported by the U.S. Department of Energy under grant no. B341495 to the ASCI Flash Center at the University of Chicago.

  7. Fast Simulations of Gas Sloshing and Cold Front Formation

    NASA Technical Reports Server (NTRS)

    Roediger, E.; ZuHone, J. A.

    2012-01-01

    We present a simplified and fast method for simulating minor mergers between galaxy clusters. Instead of following the evolution of the dark matter halos directly by the N-body method, we employ a rigid potential approximation for both clusters. The simulations are run in the rest frame of the more massive cluster and account for the resulting inertial accelerations in an optimised way. We test the reliability of this method for studies of minor merger induced gas sloshing by performing a one-to-one comparison between our simulations and hydro+N-body ones. We find that the rigid potential approximation reproduces the sloshing-related features well except for two artifacts: the temperature just outside the cold fronts is slightly over-predicted, and the outward motion of the cold fronts is delayed by typically 200 Myr. We discuss reasons for both artifacts.

  8. Fast Simulations of Gas Sloshing and Cold Front Formation

    NASA Technical Reports Server (NTRS)

    Roediger, E.; ZuHone, J. A.

    2011-01-01

    We present a simplified and fast method for simulating minor mergers between galaxy clusters. Instead of following the evolution of the dark matter halos directly by the N-body method, we employ a rigid potential approximation for both clusters. The simulations are run in the rest frame of the more massive cluster and account for the resulting inertial accelerations in an optimised way. We test the reliability of this method for studies of minor merger induced gas sloshing by performing a one-to-one comparison between our simulations and hydro+N-body ones. We find that the rigid potential approximation reproduces the sloshing-related features well except for two artefacts: the temperature just outside the cold fronts is slightly over-predicted, and the outward motion of the cold fronts is delayed by typically 200 Myr. We discuss reasons for both artefacts.

  9. Droplet and bubble formation of combined oil and gas releases in subsea blowouts.

    PubMed

    Zhao, Lin; Boufadel, Michel C; King, Thomas; Robinson, Brian; Gao, Feng; Socolofsky, Scott A; Lee, Kenneth

    2017-07-15

    Underwater blowouts from gas and oil operations often involve the simultaneous release of oil and gas. Presence of gas bubbles in jets/plumes could greatly influence oil droplet formation. With the aim of understanding and quantifying the droplet formation from Deepwater Horizon blowout (DWH) we developed a new formulation for gas-oil interaction with jets/plumes. We used the jet-droplet formation model VDROP-J with the new module and the updated model was validated against laboratory and field experimental data. Application to DWH revealed that, in the absence of dispersant, gas input resulted in a reduction of d50 by up to 1.5mm, and maximum impact occurred at intermediate gas fractions (30-50%). In the presence of dispersant, reduction in d50 due to bubbles was small because of the promoted small sizes of both bubbles and droplets by surfactants. The new development could largely enhance the prediction and response to oil and gas blowouts. Copyright © 2017. Published by Elsevier Ltd.

  10. Formation of complex organic molecules in cold objects: the role of gas-phase reactions

    NASA Astrophysics Data System (ADS)

    Balucani, Nadia; Ceccarelli, Cecilia; Taquet, Vianney

    2015-04-01

    While astrochemical models are successful in reproducing many of the observed interstellar species, they have been struggling to explain the observed abundances of complex organic molecules. Current models tend to privilege grain surface over gas-phase chemistry in their formation. One key assumption of those models is that radicals trapped in the grain mantles gain mobility and react on lukewarm ( ≳ 30 K) dust grains. Thus, the recent detections of methyl formate (MF) and dimethyl ether (DME) in cold objects represent a challenge and may clarify the respective role of grain-surface and gas-phase chemistry. We propose here a new model to form DME and MF with gas-phase reactions in cold environments, where DME is the precursor of MF via an efficient reaction overlooked by previous models. Furthermore, methoxy, a precursor of DME, is also synthesized in the gas phase from methanol, which is desorbed by a non-thermal process from the ices. Our new model reproduces fairly well the observations towards L1544. It also explains, in a natural way, the observed correlation between DME and MF. We conclude that gas-phase reactions are major actors in the formation of MF, DME and methoxy in cold gas. This challenges the exclusive role of grain-surface chemistry and favours a combined grain-gas chemistry.

  11. Surfactants from the gas phase may promote cloud droplet formation

    PubMed Central

    Sareen, Neha; Schwier, Allison N.; Lathem, Terry L.; Nenes, Athanasios; McNeill, V. Faye

    2013-01-01

    Clouds, a key component of the climate system, form when water vapor condenses upon atmospheric particulates termed cloud condensation nuclei (CCN). Variations in CCN concentrations can profoundly impact cloud properties, with important effects on local and global climate. Organic matter constitutes a significant fraction of tropospheric aerosol mass, and can influence CCN activity by depressing surface tension, contributing solute, and influencing droplet activation kinetics by forming a barrier to water uptake. We present direct evidence that two ubiquitous atmospheric trace gases, methylglyoxal (MG) and acetaldehyde, known to be surface-active, can enhance aerosol CCN activity upon uptake. This effect is demonstrated by exposing acidified ammonium sulfate particles to 250 parts per billion (ppb) or 8 ppb gas-phase MG and/or acetaldehyde in an aerosol reaction chamber for up to 5 h. For the more atmospherically relevant experiments, i.e., the 8-ppb organic precursor concentrations, significant enhancements in CCN activity, up to 7.5% reduction in critical dry diameter for activation, are observed over a timescale of hours, without any detectable limitation in activation kinetics. This reduction in critical diameter enhances the apparent particle hygroscopicity up to 26%, which for ambient aerosol would lead to cloud droplet number concentration increases of 8–10% on average. The observed enhancements exceed what would be expected based on Köhler theory and bulk properties. Therefore, the effect may be attributed to the adsorption of MG and acetaldehyde to the gas–aerosol interface, leading to surface tension depression of the aerosol. We conclude that gas-phase surfactants may enhance CCN activity in the atmosphere. PMID:23382211

  12. Formation characteristics of synthesized natural gas hydrates in meso- and macroporous silica gels.

    PubMed

    Kang, Seong-Pil; Lee, Jong-Won

    2010-05-27

    Phase equilibria and formation kinetics of the natural gas hydrate in porous silica gels were investigated using the natural gas composition in the Korean domestic natural gas grid. The hydrate-phase equilibria in the porous media are found to shift to the inhibition area than that in the bulk phase. The measured phase equilibrium data, combined with the Gibbs-Thomson equation, were used to calculate the hydrate-water interfacial tension. The value was estimated to be 59.74 +/- 2 mJ/m(2) for the natural gas hydrate. In addition, the inhibition effect is observed to be more significant in the meso-sized pore than the macro-sized one. In the formation kinetics, it was found that the hydrate formation reached the steady-state in a short period of time without mechanical stirring. Furthermore, the formation rate was found to be faster at 275.2 K than 273.2 K even though the driving force at 273.2 K is larger than that of 275.2 K. Even though the porous silica gels have smaller volume than other methods for gas storage, the gas consumption was found to be significantly enhanced in this study (for example, 120 vol/vol for the silica gels and 97 vol/vol for wet activated carbon). In this regard, using porous silica gels can be a potential alternative for gas storage and transportation as a nonmechanical stirring method. Although this investigation was performed with the natural gas composition in the Korean domestic grid, the results can also be expanded for designing or operating any hydrate-based process using various gas compositions.

  13. [Brucellar spinal abscess. Case report

    PubMed

    Cecchini, L.; Coari, G.; Iagnocco, A.; Valesini, G.

    2001-01-01

    Brucellosis is a zoonosis commonly present in many areas of the world; in some Mediterranean countries it is endemic. The disease is usually transmitted to humans by ingestion of contaminated food; rarely it may be transmitted either by direct penetration through skin lesions or conjunctival mucosa or even by inhalation of aerosols. The disease may be asymptomatic, but in some occasions acute or chronic symptoms are present. Among localised forms of the disease spinal involvement is rare but it should be suspected in many Mediterranean areas where brucellosis is endemic. In particular, the extension of the brucellar abscess within the epidural space with contemporaneous muscular involvement is unusual. The authors report a case of a patient with multiple spinal brucellar abscesses of exceptional dimensions, extending in the epidural space and within paravertebral and psoas muscles and causing compression of the lumbar nerve roots. The exact localisation and extension of the abscess have been accurately defined by MRI.

  14. Brain abscess following intra-arterial thrombolytic treatment for acute brain ischemia.

    PubMed

    Yamanaka, Kazunori; Ishihara, Masahiro; Nakajima, Shin; Yamasaki, Mami; Yoshimine, Toshiki

    2011-07-01

    Brain abscess formation is a rare complication of intracranial endovascular treatment. To our knowledge, all previous reports of brain abscess formation have been associated with treatments involving the introduction of foreign materials. A 75-year-old man was admitted to hospital for acute stroke. Cerebral angiography revealed occlusion of the left middle cerebral artery (MCA) at the origin of the M2 segment. Intra-arterial thrombolytic therapy was administered but a hemorrhagic event occurred during this process. A brain CT scan revealed a hematoma extending from the left basal ganglia to the left frontal lobe and expansion of the infarct in the left MCA territory. A brain abscess at the hemorrhagic site developed 3 months after symptom onset. This is the first report of a patient with brain abscess formation following intra-arterial thrombolytic treatment. It is important to ensure aseptic technique during endovascular procedures irrespective of the involvement of foreign materials. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Formation of natural gas hydrates in marine sediments 1. Conceptual model of gas hydrate growth conditioned by host sediment properties

    USGS Publications Warehouse

    Clennell, M.B.; Hovland, M.; Booth, J.S.; Henry, P.; Winters, W.J.

    1999-01-01

    The stability of submarine gas hydrates is largely dictated by pressure and temperature, gas composition, and pore water salinity. However, the physical properties and surface chemistry of deep marine sediments may also affect the thermodynamic state, growth kinetics, spatial distributions, and growth forms of clathrates. Our conceptual model presumes that gas hydrate behaves in a way analogous to ice in a freezing soil. Hydrate growth is inhibited within fine-grained sediments by a combination of reduced pore water activity in the vicinity of hydrophilic mineral surfaces, and the excess internal energy of small crystals confined in pores. The excess energy can be thought of as a "capillary pressure" in the hydrate crystal, related to the pore size distribution and the state of stress in the sediment framework. The base of gas hydrate stability in a sequence of fine sediments is predicted by our model to occur at a lower temperature (nearer to the seabed) than would be calculated from bulk thermodynamic equilibrium. Capillary effects or a build up of salt in the system can expand the phase boundary between hydrate and free gas into a divariant field extending over a finite depth range dictated by total methane content and pore-size distribution. Hysteresis between the temperatures of crystallization and dissociation of the clathrate is also predicted. Growth forms commonly observed in hydrate samples recovered from marine sediments (nodules, and lenses in muds; cements in sands) can largely be explained by capillary effects, but kinetics of nucleation and growth are also important. The formation of concentrated gas hydrates in a partially closed system with respect to material transport, or where gas can flush through the system, may lead to water depletion in the host sediment. This "freeze-drying" may be detectable through physical changes to the sediment (low water content and overconsolidation) and/or chemical anomalies in the pore waters and metastable

  16. Formation resistivity measurements from within a cased well used to quantitatively determine the amount of oil and gas present

    DOEpatents

    Vail, III, William B.

    1997-01-01

    Methods to quantitatively determine the separate amounts of oil and gas in a geological formation adjacent to a cased well using measurements of formation resistivity are disclosed. The steps include obtaining resistivity measurements from within a cased well of a given formation, obtaining the porosity, obtaining the resistivity of formation water present, computing the combined amounts of oil and gas present using Archie's Equations, determining the relative amounts of oil and gas present from measurements within a cased well, and then quantitatively determining the separate amounts of oil and gas present in the formation.

  17. Formation resistivity measurements from within a cased well used to quantitatively determine the amount of oil and gas present

    DOEpatents

    Vail, W.B. III

    1997-05-27

    Methods to quantitatively determine the separate amounts of oil and gas in a geological formation adjacent to a cased well using measurements of formation resistivity are disclosed. The steps include obtaining resistivity measurements from within a cased well of a given formation, obtaining the porosity, obtaining the resistivity of formation water present, computing the combined amounts of oil and gas present using Archie`s Equations, determining the relative amounts of oil and gas present from measurements within a cased well, and then quantitatively determining the separate amounts of oil and gas present in the formation. 7 figs.

  18. Gas, Water, and Oil Production from the Wasatch Formation, Greater Natural Buttes Field, Uinta Basin, Utah

    USGS Publications Warehouse

    Nelson, Philip H.; Hoffman, Eric L.

    2009-01-01

    Gas, oil, and water production data were compiled from 38 wells with production commencing during the 1980s from the Wasatch Formation in the Greater Natural Buttes field, Uinta Basin, Utah. This study is one of a series of reports examining fluid production from tight gas reservoirs, which are characterized by low permeability, low porosity, and the presence of clay minerals in pore space. The general ranges of production rates after 2 years are 100-1,000 mscf/day for gas, 0.35-3.4 barrel per day for oil, and less than 1 barrel per day for water. The water:gas ratio ranges from 0.1 to10 barrel per million standard cubic feet, indicating that free water is produced along with water dissolved in gas in the reservoir. The oil:gas ratios are typical of a wet gas system. Neither gas nor water rates show dependence upon the number of perforations, although for low gas-flow rates there is some dependence upon the number of sandstone intervals that were perforated. Over a 5-year time span, gas and water may either increase or decrease in a given well, but the changes in production rate do not exhibit any dependence upon well proximity or well location.

  19. Simulation of production and injection performance of gas storage caverns in salt formations

    SciTech Connect

    Hagoort, J. )

    1994-11-01

    This paper presents a simple yet comprehensive mathematical model for simulation of injection and production performance of gas storage caverns in salt formations. The model predicts the pressure and temperature of the gas in the cavern and at the wellhead for an arbitrary sequence of production and injection cycles. The model incorporates nonideal gas properties, thermodynamic heat effects associated with gas expansion and compression in the cavern and tubing, heat exchange with the surrounding salt formation, and non-uniform initial temperatures but does not include rock-mechanical effects. The model is based on a mass and energy balance for the gas-filled cavern and on the Bernoulli equation and energy balance for flow in the wellbore. Cavern equations are solved iteratively at successive timesteps, and wellbore equations are solved within an iteration cycle of the cavern equations. Gas properties are calculated internally with generally accepted correlations and basic thermodynamic relations. Example calculations show that the initial temperature distribution has a strong effect on production performance of a typical gas storage cavern. The primary application of the model is in the design, planning, and operation of gas storage projects.

  20. Gas Content and Star Formation Efficiency of Massive Main Sequence Galaxies at z~3-4

    NASA Astrophysics Data System (ADS)

    Schinnerer, Eva; Groves, Brent; Karim, Alexander; Sargent, Mark T.; Oesch, Pascal; Le Fevre, Olivier; Tasca, Lidia; Magnelli, Benjamin; Cassata, Paolo; Smolcic, Vernesa

    2016-01-01

    Recent observations have shown that the neutral gas content and star formation efficiency of massive (with log(stellar masses) > 10), normal star forming galaxies, i.e. they reside on the main sequence of star forming galaxies, are steadily decreasing from the peak of star formation activity (at redshifts of z~2) till today. This decrease is coincident with the observed decline in the cosmic star formation rate density over this time range. However, only few observations have probed the evolution of the gas content and star formation efficiency beyond this peak epoch when the cosmic star formation rate density has been increasing, i.e. at redshifts of z~3-4.We will present new ALMA rest-frame 250um continuum detections of 45 massive, normal star forming galaxies in this critical redshift interval selected in the COSMOS deep field. Using the sub-mm continnum as proxy for the cold neutral gas content, we find gas mass fractions and depletions similar to those reported during the peak epoch of star formation. We will discuss our findings in the context of results from lower redshift observations and model expectations.

  1. Computed tomographic differences of pyogenic liver abscesses caused by Klebsiella pneumoniae and non-Klebsiella pneumoniae.

    PubMed

    Kim, Sung-Bum; Je, Bo-Kyung; Lee, Kee Yeol; Lee, Seung Hwa; Chung, Hwan-Hoon; Cha, Sang Hoon

    2007-01-01

    To investigate the distinctive computed tomographic(CT) features of pyogenic liver abscess (PLA) caused by Klebsiella pneumoniae (KLA). 114 PLA patients (62 men, 52 women, age range 25-89 years, mean age 60.9 years) with positive yield of blood or pus cultures were divided into 2 groups; KLA group (n = 58) and non-KLA group (n = 56). We retrospectively reviewed the CT images. The independent-sample t-test, X2 test, or Fisher's exact test were used with SPSS for windows version 11.0. Gas formation showed no significant difference between two groups (P = 0.284), but air-fluid pattern was found only in KLA group (P = 0.027). The rim on dynamic CT was showed less frequently in KLA group than non-KLA group (P < 0.001), and smooth and regular rim was more common in non-KLA group (P < 0.001). The septation and septal breakage were more common in KLA group (P < 0.001). The turquoise sign was found significantly more in KLA group (P < 0.001). The hairball sign was detected only in KLA group (P < 0.001). The cluster sign was less frequent in KLA group (P < 0.001). KLA had a series of characteristic intra-abscess features; septal breakage, turquoise-like structure, hairball-like content, air-fluid level, and no enhanced rim. When turquoise/hairball sign or air-fluid level is present in abscess, KLA would be a probable diagnosis in the clinical field.

  2. Star Formation and Dense Gas in Galaxy Mergers from the VIXENS Survey

    NASA Astrophysics Data System (ADS)

    Heiderman, Amanda L.; VIXENS Team

    2016-01-01

    We present our λ= 3 mm IRAM and NRO single dish line survey for a sample of 15 interacting galaxies in the VIRUS-P Investigation of the eXtreme ENvironments of Starbursts (VIXENS) survey. Our sample of merging galaxies range from early to late interaction stages (close pairs to merger remnants, respectively). A variety of molecular lines are detected including dense gas tracers HCN, HCO+, HNC, CS, CN (and others) as well as 12CO and 13CO. We compare the dense gas fractions with 12CO and 13CO as well as star formation efficiencies defined by infrared-to-dense gas tracer luminosity ratio and discuss trends with interaction stage. We also investigate relations between star formation and dense gas content in our merger sample and compare them to non-interacting star forming galaxies and Galactic star forming regions in the Milky Way.

  3. Risk factors and clinical outcomes for spontaneous rupture of pyogenic liver abscess.

    PubMed

    Jun, Chung Hwan; Yoon, Jae Hyun; Wi, Jin Woo; Park, Seon Young; Lee, Wan Sik; Jung, Sook In; Park, Chang Hwan; Joo, Young Eun; Kim, Hyun Soo; Choi, Sung Kyu; Rew, Jong Sun

    2015-01-01

    To evaluate the risk factors and clinical outcomes in patients with spontaneous rupture of pyogenic liver abscess (PLA). A total of 602 patients diagnosed with PLA between January 2004 and July 2013 were retrospectively analyzed. Among them, 23 patients experienced a spontaneous rupture of liver abscess (SRLA). The prevalence of SRLA was 3.8%. Using multivariate analysis, liver cirrhosis (OR 4.651, P = 0.009), gas-forming abscesses (OR 3.649, P = 0.026), abscess ≥6 cm in diameter (OR 10.989, P = 0.002) and other septic metastases (OR 1.710, P = 0.047) were risk factors for SRLA. Regarding the site of rupture, 20 (87.0%) patients had a localized rupture, specifically, subphrenic abscess in 3 (13.0%), peri-hepatic abscess in 10 (43.5%), localized peritoneal abscess in 3 (13.0%) and empyema in 4 (17.5%); and the other 3 (13%) had peritonitis. Ruptures resulting in peritonitis require urgent surgery, whereas localized ruptures were managed with surgical or percutaneous drainage in addition to appropriate antibiotics. The in-hospital mortality rate of SRLA was 4.3%. Patients with cirrhosis, having abscess ≥6 cm in diameter, gas-forming abscesses and other septic metastases in those with PLA should be monitored closely and may need early intervention for SRLA. © 2014 Chinese Medical Association Shanghai Branch, Chinese Society of Gastroenterology, Renji Hospital Affiliated to Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd.

  4. [Iliopsoas abscess accompanied by epidural abscess--a case report].

    PubMed

    Fukushige, Tetsushi; Sano, Tomomi; Yamada, Sinichi; Ueda, Sawako; Kano, Tatsuhiko

    2003-09-01

    A 55-year-old man was admitted to a hospital with pain of the low back as well as the left leg, and fever. He was suspected of suffering from the lumbar disc herniation because of the presence of Lasegue's sign on the first physical examination. Abdominal computed tomography, however, revealed the swelling of the left iliopsoas muscle. Iliopsoas abscess accompanied epidural abscess was confirmed by subsequent magnetic resonance imaging (MRI). Antibiotic therapy was started for the successive 8 days. The fever resolved, but the pain persisted. The abscess extending from the iliopsoas muscle to the epidural space was still seen on the MRI 20 days after the completion of the antibiotic therapy, and he still complained of the pain of his low back and left leg. Therefore, we conducted epidural puncture under fluoroscopic guidance. Approximately 3 ml of pus was aspirated from the epidural space. Then, his complains decreased remarkably. Iliopsoas abscess should be taken into account in case of a patient with pain on the low back and leg and also inflammatory signs such as fever and leucocytosis.

  5. The clinical spectrum of chronic appendiceal abscess in cystic fibrosis.

    PubMed

    Allen, E D; Pfaff, J K; Taussig, L M; McCoy, K S

    1992-10-01

    To describe the varied characteristics seen in patients with cystic fibrosis who develop chronic abscess formation secondary to unrecognized appendicitis. Patient series. Cystic Fibrosis Care Centers in Columbus, Ohio, and Tucson, Ariz. Five patients with cystic fibrosis who developed chronic abdominal abscesses secondary to occult appendicitis are described. Two patients developed fistula formation with purulent fluid drainage before diagnosis. One patient developed an extensive psoas abscess. Another presented with prolonged fever of unknown origin. These patients were identified by retrospective review of the past 20-year experience at two Cystic Fibrosis Care Centers. Development of chronic abdominal abscess related to unrecognized appendicitis is a rare but important complication in patients with cystic fibrosis. Prompt diagnosis depends on physician familiarity with the varied presentations of this entity. Diagnostic abdominal computed tomography and/or ultrasonography should particularly be considered when patients with cystic fibrosis present with pain, mass, or drainage from the right flank; prolonged fever; a limp; or failure of suspected meconium ileus equivalent syndrome to respond promptly to cathartic measures.

  6. Bar formation as driver of gas inflows in isolated disc galaxies

    NASA Astrophysics Data System (ADS)

    Fanali, R.; Dotti, M.; Fiacconi, D.; Haardt, F.

    2015-12-01

    Stellar bars are a common feature in massive disc galaxies. On a theoretical ground, the response of gas to a bar is generally thought to cause nuclear starbursts and, possibly, AGN activity once the perturbed gas reaches the central supermassive black hole. By means of high-resolution numerical simulations, we detail the purely dynamical effects that a forming bar exerts on the gas of an isolated disc galaxy. The galaxy is initially unstable to the formation of non-axisymmetric structures, and within ˜1 Gyr it develops spiral arms that eventually evolve into a central stellar bar on kpc scale. A first major episode of gas inflow occurs during the formation of the spiral arms while at later times, when the stellar bar is establishing, a low-density region is carved between the bar corotational and inner Lindblad resonance radii. The development of such `dead zone' inhibits further massive gas inflows. Indeed, the gas inflow reaches its maximum during the relatively fast bar-formation phase and not, as often assumed, when the bar is fully formed. We conclude that the low efficiency of long-lived, evolved bars in driving gas towards galactic nuclei is the reason why observational studies have failed to establish an indisputable link between bars and AGNs. On the other hand, the high efficiency in driving strong gas inflows of the intrinsically transient process of bar formation suggests that the importance of bars as drivers of AGN activity in disc galaxies has been overlooked so far. We finally prove that our conclusions are robust against different numerical implementations of the hydrodynamics routinely used in galaxy evolution studies.

  7. Gas heating effects on the formation and propagation of a microwave streamer in air

    NASA Astrophysics Data System (ADS)

    Kourtzanidis, Konstantinos; Rogier, François; Boeuf, Jean-Pierre

    2015-09-01

    The development of microwave plasma streamers at 110 GHz in atmospheric pressure air is numerically investigated taking into account the intense gas heating and its effects on the plasma formation and dynamics. The simulations are based on an implicit finite difference time domain formulation of Maxwell's equations coupled with a simple plasma fluid model and a real gas Euler equation solver. The numerical results show how the formation of a shock wave due to the large microwave power absorbed by the plasma and converted into gas heating strongly modifies the streamer elongation and dynamics. A microwave streamer filament stretches along its axis because of ionization-diffusion mechanisms in the enhanced electric field at the streamer tips. The change in the gas density distribution associated with the formation of shock wave due to gas heating strongly modifies the ionization and diffusion mechanisms and tends to limit the on-axis microwave streamer elongation by enhancing resonance effects. The simulations suggest that gas heating effects also play an important role in the observed bending or branching of microwave streamers after they have reached a critical length.

  8. Theoretical models of gas dynamics and star formation in interacting ring galaxies

    NASA Technical Reports Server (NTRS)

    Struck-Marcell, Curtis

    1990-01-01

    A series of one and two dimensional hydrodynamic simulations of a ring wave in interstellar gas disks was completed. These calculations included nonlinear source terms to model the effects of interstellar interactions and star formation, as well as the spatial-temporal gas flow. Toomre's kinematical model was merged with the Arnold, Shandarin, and Zeldovich 'pancake' theory of caustics in galaxy formation. The resulting theory can describe almost all the structure in restricted three-body simulations of single-pass collisions, even with multi-component potentials. Off-center galactic collisions were studied to understand the dynamics involved. Multi-color optical and near-infrared observations of faint tidal features were performed in about two dozen interacting galaxies selected from the Arp atlas. This sample provided evidence for ongoing star formation in tidal structures, and even enhancements of star formation in some cases. The task of assembling the data for gas-rich, late-type galaxies, was undertaken to see if a more coherent picture of the gas distribution would emerge from the more complete data. Analytic solutions of the equations with subsonic flows to balance gas consumption for expulsion form a galactic fountain were also derived.

  9. Formation of molecular gas in the tidal debris of violent galaxy-galaxy interactions.

    PubMed

    Braine, J; Lisenfeld, U; Duc, P A; Leon, S; Due, P A

    2000-02-24

    In many gravitational interactions between galaxies, gas and stars that have been torn from the precursor galaxies can collect in tidal 'tails'. Star formation begins anew in some of these regions, producing tidal dwarf galaxies. Observations of these new galaxies provides insight into processes relevant to galaxy formation more generally, because the timescale of the interaction is well defined. But tracking the star formation process has hitherto been difficult because the tidal dwarf galaxies with young stars showed no evidence of the molecular gas out of which those young stars formed. Here we report the discovery of molecular hydrogen (traced by carbon monoxide emission) in two tidal dwarf galaxies. In both cases, the concentration of molecular gas peaks at the same location as the maximum in atomic-hydrogen density, unlike the situation in most gas-rich galaxies. We infer from this that the molecular gas formed from the atomic hydrogen, rather than being torn in molecular form from the interacting galaxies. Star formation in the tidal dwarf galaxies therefore appears to mimic the process in normal spiral galaxies like our own.

  10. Star Formation Rate and Gas Relations in the Arp 299 Merger from the VIXENS Survey

    NASA Astrophysics Data System (ADS)

    Heiderman, Amanda L.; Evans, N. J.; Gebhardt, K.; Blanc, G. A.; Davis, T.; Papovich, C. J.; van den Bosch, R.; Iono, D.; Yun, M.; VIXENS Team

    2014-01-01

    We investigate the relationship between star formation and gas content in late interaction phase merger Arp 299 from the VIRUS-P Investigation of the eXtreme ENvironments of Starbursts (VIXENS) integral field unit survey. By comparing H-alpha, Pa-alpha and 24um data to CO(1-0), CO(2-1), HCN(1-0), HCO+(1-0), and HI maps, we explore the relation between the star formation rate and gas surface densities on spatially resolved ~kpc scales. We find discrepancies from known extragalactic spatially resolved relations in nearby spiral galaxies and disk-averaged relations in high-z mergers.

  11. Interdisciplinary Investigation of CO2 Sequestration in Depleted Shale Gas Formations

    SciTech Connect

    Zoback, Mark D.; Kovscek, Anthony R.; Wilcox, Jennifer

    2013-09-30

    This project investigates the feasibility of geologic sequestration of CO2 in depleted shale gas reservoirs from an interdisciplinary viewpoint. It is anticipated that over the next two decades, tens of thousands of wells will be drilled in the 23 states in which organic-rich shale gas deposits are found. This research investigates the feasibility of using these formations for sequestration. If feasible, the number of sites where CO2 can be sequestered increases dramatically. The research embraces a broad array of length scales ranging from the ~10 nanometer scale of the pores in the shale formations to reservoir scale through a series of integrated laboratory and theoretical studies.

  12. Gas cluster ion beam assisted NiPt germano-silicide formation on SiGe

    SciTech Connect

    Ozcan, Ahmet S.; Lavoie, Christian; Jordan-Sweet, Jean; Alptekin, Emre; Zhu, Frank; Leith, Allen; Pfeifer, Brian D.; LaRose, J. D.; Russell, N. M.

    2016-04-21

    We report the formation of very uniform and smooth Ni(Pt)Si on epitaxially grown SiGe using Si gas cluster ion beam treatment after metal-rich silicide formation. The gas cluster ion implantation process was optimized to infuse Si into the metal-rich silicide layer and lowered the NiSi nucleation temperature significantly according to in situ X-ray diffraction measurements. This novel method which leads to more uniform films can also be used to control silicide depth in ultra-shallow junctions, especially for high Ge containing devices, where silicidation is problematic as it leads to much rougher interfaces.

  13. Formation of a Multi-Charged Plasma in the Directed Gas Flow

    NASA Astrophysics Data System (ADS)

    Abramov, I. S.; Gospodchikov, E. D.; Shalashov, A. G.

    2016-05-01

    We consider a gas-dynamic model describing the formation of a plasma with multiply ionized ions under the conditions of resonant heating of the electron component. Based on the isothermal approximation, possible regimes of the plasma flow are classified, the influence of the geometric divergence of the flow on the formation of the ion charge distribution is studied, and optimal regimes for the achievement of the maximum ion charge are identified. The model can be used for optimization and interpretation of modern experiments on generation of the extreme ultraviolet radiation due to the excitation of lines of multiply ionized atoms in a gas flow heated by strong millimeter or submillimeter waves.

  14. Low-mass spiral galaxies with little molecular gas and prodigious star formation

    NASA Technical Reports Server (NTRS)

    Kenney, Jeffrey D.; Young, Judith S.

    1988-01-01

    A comparison of CO and H I properties is used here to demonstrate that many CO-poor low-mass Virgo spiral galaxies are rich in atomic gas, which implies that the lack of CO emission from them is due, at least partly, to a lack of molecular gas. Despite the paucity of molecular gas, these H I-rich, CO-poor, low-mass spiral galaxies are undergoing extensive massive star formation. A column density of 10 to the 21st nuclei/sq cm is a necessary but insufficient condition for the creation of an H2-dominated interstellar medium.

  15. Cool gas accretion, thermal evaporation, and quenching of star formation in elliptical galaxies

    NASA Astrophysics Data System (ADS)

    Nipoti, C.

    2009-12-01

    The most evident features of colour-magnitude diagrams of galaxies are the red sequence of quiescent galaxies, extending up to the brightest elliptical galaxies, and the blue cloud of star-forming galaxies, which is truncated at a luminosity L˜ {L}*. The truncation of the blue cloud indicates that in the most massive systems star formation must be quenched. For this to happen the virial-temperature galactic gas must be kept hot and any accreted cold gas must be heated. The elimination of accreted cold gas can be due to thermal evaporation by the hot interstellar medium, which in turn is prevented from cooling by feedback from active galactic nuclei.

  16. Large Retropharyngeal Abscesses in an Immunocompetent Adult Patient with Disseminated Tuberculosis

    PubMed Central

    Amaya-Tapia, Gerardo; Rodríguez-Toledo, Arturo; Aguilar-Benavides, Sergio; Aguirre-Avalos, Guadalupe

    2016-01-01

    Patient: Male, 46 Final Diagnosis: Generalized tuberculous lymphadenitis with retropharyngeal abscesses and disseminated tuberculosis Symptoms: Lymphadenopathy • dysphagia • weight loss Medication: — Clinical Procedure: — Specialty: Infectious Diseases Objective: Unusual clinical course Background: The retropharyngeal abscess is a rare presentation of head and neck tuberculosis. The pathogenesis of the abscess formation in the retropharyngeal space in the adult is controversial. Case Report: We report a case of large retropharyngeal abscesses in a 46-year-old man with disseminated tuberculosis. The patient had severe progressive dysphagia, weight loss, and a slowly enlarging bilateral cervical mass during a period of three months. His posterior pharynx wall was bulging and red, and both tonsils were enlarged and congested. The neck had an abscess of 5 cm in diameter that was firm, tender, and warm along the left sternocleidomastoid muscle. Palpable bilateral lymphadenitis was detected in the submandibular, cervical, axillary, and inguinal regions. A computed tomographic (CT) scan of the neck revealed large bilobulated retropharyngeal abscesses. A liver ultrasound showed multiple hypoechoic lesions. A Ziehl-Neelsen smear for acid-fast bacilli was positive from different abscess samples, and mycobacterial cultures subsequently yielded Mycobacterium tuberculosis. Antituberculous therapy was begun and the retropharyngeal abscesses were aspirated by external incision with complete drainage and relief of symptoms. Conclusions: Large retropharyngeal abscess is a rare entity in which Mycobacterium tuberculosis etiology should be considered, especially in endemic countries, and the diagnosis may be difficult because symptoms and signs are influenced by abscess size and time of onset, or if the etiology is not suspected. PMID:27680292

  17. New method for prediction of shale gas content in continental shale formation using well logs

    NASA Astrophysics Data System (ADS)

    Li, Sheng-Jie; Cui, Zhe; Jiang, Zhen-Xue; Shao, Yu; Liao, Wei; Li, Li

    2016-06-01

    Shale needs to contain a sufficient amount of gas to make it viable for exploitation. The continental heterogeneous shale formation in the Yan-chang (YC) area is investigated by firstly measuring the shale gas content in a laboratory and then investigating use of a theoretical prediction model. Key factors controlling the shale gas content are determined, and a prediction model for free gas content is established according to the equation of gas state and a new petrophysical volume model. Application of the Langmuir volume constant and pressure constant obtained from results of adsorption isotherms is found to be limited because these constants are greatly affected by experimental temperature and pressures. Therefore, using measurements of adsorption isotherms and thermodynamic theory, the influence of temperature, total organic carbon (TOC), and mineralogy on Langmuir volume constants and pressure constants are investigated in detail. A prediction model for the Langmuir pressure constant with a correction of temperatures is then established, and a prediction model for the Langmuir volume constant with correction of temperature, TOC, and quartz contents is also proposed. Using these corrected Langmuir constants, application of the Langmuir model determined using experimental adsorption isotherms is extrapolated to reservoir temperature, pressure, and lithological conditions, and a method for the prediction of shale gas content using well logs is established. Finally, this method is successfully applied to predict the shale gas content of the continental shale formation in the YC area, and practical application is shown to deliver good results with high precision.

  18. Appendicitis and uterine abscess: presentation of an unusual fistula between the gynaecological and gastrointestinal tracts

    PubMed Central

    Parsons, Sian Ruth; Bennett, Joanne Elizabeth; Kaloo, Philip; Scott, Mike

    2012-01-01

    The authors present the case of a 65-year-old woman with clinical and radiological evidence of pelvic sepsis and a medical history of endometrial ablation 20 years previously. She underwent laparotomy after failing to settle with a course of intravenous antibiotics and her appendix was found to have perforated into the uterus with abscess formation which had not discharged vaginally presumably due to widespread intrauterine synechia following her endometrial ablation. She underwent appendectomy and hysterectomy and made a full recovery with no complications. Macroscopic and microscopic examination suggested the appearances are those of an abscess of the uterine fundus with part of the appendix incorporating into the abscess mass. PMID:22984000

  19. Spontaneous spinal epidural abscess in a 21-month-old child.

    PubMed

    Harris, Tyler J; Seamon, Jason P

    2014-12-01

    Spontaneous epidural abscess formation is a rare finding in all populations and even more so in the pediatric population. Its rarity and varied presentations often lead to misdiagnosis. We present a pediatric case in which the diagnosis of spontaneous spinal epidural abscess was missed upon initial presentation and subsequently identified at a later visit to the emergency department. Literature suggests utilizing three simple physical exam findings that may improve the first visit diagnosis of spontaneous epidural abscesses in children. Findings of any two of the following signs should guide the clinician to consider SEA as a possibility prior to discharge: fever, back or neck pain, extremity weakness or inability to walk.

  20. [Psoas abscess. Etiology and treatment].

    PubMed

    Tonus, C; Kasparek, S; Nier, H

    2002-10-01

    Psoas abscess is in general a syndrome with low incidence. In the following, two cases are presented which describe the etiology, diagnosis, and treatment of primary and secondary retroperitoneal manifestations. The article mainly focuses on the different respective surgical procedures. Because of its rareness, an overview of further cases discussed in the literature is provided.

  1. [Prognostic study of liver abscess].

    PubMed

    Nouira, Ramzi; Bedoui, Riadh; Miaadi, Naoufel; Guesmi, Fethi; Ben Achour, Jamel; Hani, Mohamed; Daghfous, Mounir; Ben Osman, Samia; Zoghlami, Ayoub; Najah, Nabil

    2003-04-01

    The objective of this work is to study factors of prognostic of mortality of abscesses of the liver. We have treated between 1990 and 2000 in our service, 38 patient for abscess of the liver. The symptoms are dominated by the pain of the right hypochondria (37 cases) and the fever (34 cases). An unique abscess has been recovered in 25 cases. Some multiple localizations have been observed in 12 cases. 21 patients have been operated. The bacteriological study at all patients revealed the presence of germ in 27 cases. In 6 cases, there were two germs. It was a bacillus negative gram in 26 cases and a cocci positive gram in 7 cases. Six complications have been observed at the operated patients. In 5 cases, it was a septic shock having leads to the death. After survey univariate and multivariate the only factor of bad prognostic recovered is the septic shock. The aetiology was identified in only 9 cases; it was abscess cholangiotis.

  2. AMEBIC ABSCESS OF THE LIVER

    PubMed Central

    Struve, Edgar E.

    1950-01-01

    In a review of the records in 50 cases of amebic abscess of the liver observed in the Canal Zone between 1920 and 1945 the following features were noted: Incidence was preponderantly in males and highest in persons between the ages of 20 and 40. None of the patients was under 21 years of age. There was a great variety of complaints at the time of admission to hospital. The most common was pain in the right upper quadrant of the abdomen. Demonstration of either elevated or fixed diaphragm by x-ray film and fluoroscopic examination was useful in diagnosis in a number of cases, but absence of such findings did not rule out abscess of the liver. In some cases there was history of previous dysentery with blood in the stools. One or another of three operative procedures was used for drainage of abscesses in 39 patients. Of the 39, six died; in five of the six, multiple abscesses were present. Emetine hydrochloride was given to all patients. PMID:15426995

  3. Good penetration of moxifloxacin into human abscesses.

    PubMed

    Sauermann, Robert; Karch, Rudolf; Kjellsson, Maria C; Feurstein, Thomas; Püspök, Andreas; Langenberger, Herbert; Böhmdorfer, Michaela; Jäger, Walter; Zeitlinger, Markus

    2012-01-01

    Abscesses are often treated with antibiotics in addition to incision or when incision is unfeasible, but accurate information about antibiotic abscess penetration in humans is missing. This study aimed at evaluating the penetration of moxifloxacin into human abscesses. After administration of a single dose of 400 mg moxifloxacin, drug concentrations were measured in 10 differently located abscesses at incision, and in plasma over 8 h. At incision performed 0.9-4.8 h after administration, moxifloxacin concentrations in abscesses ranged from ≤0.01 to 9.2 mg/l (1.9 ± 3.4 mg/l), indicating pronounced drug accumulation in some abscesses. The degree of abscess penetration could not be explained by covariates like the ratio of surface area to volume or pH of abscesses, or by moxifloxacin plasma concentrations. Concluding, moxifloxacin was detectable in most abscesses and may be a useful antibiotic for this indication. However, antibiotic abscess penetration was highly variable and unpredictable, suggesting surgical abscess incision whenever possible.

  4. High-resolution seafloor features related to potential gas-hydrate formation off SW Taiwan

    NASA Astrophysics Data System (ADS)

    Hsu, S.; Tsai, C.; Chen, S.; Shih, T.

    2010-12-01

    The area off SW Taiwan is considered as a high potential area for gas-hydrate formation. The gas-hydrate signature is indicated by the abundant presence of BSR (Bottom-Simulating-Reflector). High methane concentration is also shown in the bottom water near the seafloor. To have a better understanding, we have conducted deep-towed survey of side-scan sonar and sub-bottom profiler in several potential areas. Pockmarks are found in several places. Some are related to gas seeping. The gas seeps are especially obvious in high-resolution sub-bottom profilers. The high pore-pressure due to the charging of the gas has clearly uplifted a top layer of sediments. The pockmarks area usually accompany the presence of authigenic carbonate. In the image of side-scan sonar data, the irregular patterns of strong backscatter signal are associated with the gas seeping or pockmark sites. The presence of pockmarks or gas seeps could be related to structural faults. Because the NW convergence of the Philippine Sea plate relative to the Eurasian plate, the area off SW Taiwan in fact is under compression and has caused folds and faults. These structural faults provide efficient conduits for fluid to migrate upward. Thus, the pockmarks frequently appear near faults. In the water depth of about 450m, the upward gas even goes into water column and creates clear gas plume image in EK 500 data. The gas is inferred to be dissociated from gas-hydrate and can get into the atmosphere. The dissociation of gas-hydrate has probably also induced the instability of the seafloor off SW Taiwan and cuased submarine landslides.

  5. Investigating the Potential for Large-Scale Carbon Dioxide Sequestration in Shale Gas Formations

    NASA Astrophysics Data System (ADS)

    Edwards, R.; Celia, M. A.; Kanno, C.; Bandilla, K.; Doster, F.

    2014-12-01

    Recent studies [Godec et al., Int. J. Coal. Geol., 2013; Liu et al., IJGGC, 2013; Tao and Clarens, ES&T, 2013] have suggested the possibility of geological CO2 sequestration in depleted shale gas formations, motivated by large storage capacity estimates in these formations. The kinetics and practicality of injecting large amounts of CO2 into shale gas wells at the appropriate scale remain as open questions. To further investigate the feasibility of CO2 sequestration, models of gas flow and storage in a horizontal shale gas well were developed based on observed behavior of gas production data and the associated models that are consistent with those observations [Patzek et al., PNAS, 2013]. Both analytical and numerical models were used to investigate the well-scale kinetics of CO2 injection into a typical shale gas well. It was found that relatively low rates could be injected into individual wells compared with CO2 emissions from large industrial sources, and that injection rates would rapidly decline with time. Based on typical well parameters, 170 wells would be required to inject the emissions from one large coal-fired power plant over a 15 year period. Significant practical and logistical challenges to industrial-scale CO2 sequestration in depleted shale gas formations arise due to the relatively low injection rates, low storage capacity of individual wells and large numbers of wells required. These challenges include the difficulty of managing the required large, ever-changing networks of injection wells, potentially prohibitive energy requirements, and leakage concerns in hydraulically fractured wells. The combination of these factors, and the fact that they are all likely less of an issue for other potential geological sequestration targets such as deep saline aquifers, mean that targets in conventional formations are more likely to be suitable for industrial-scale CO2 sequestration.

  6. Molecular Gas and Star Formation in the Cartwheel

    NASA Astrophysics Data System (ADS)

    Higdon, James L.; Higdon, Sarah J. U.; Martín Ruiz, Sergio; Rand, Richard J.

    2015-11-01

    Atacama Large Millimeter/submillimeter Array 12CO(J = 1-0) observations are used to study the cold molecular ISM of the Cartwheel ring galaxy and its relation to H i and massive star formation (SF). CO moment maps find (2.69 ± 0.05) × 109 M⊙ of H2 associated with the inner ring (72%) and nucleus (28%) for a Galactic ICO-to-{N}{{{H}}2} conversion factor (αCO). The spokes and disk are not detected. Analysis of the inner ring's CO kinematics shows it to be expanding (Vexp = 68.9 ± 4.9 km s-1), implying an ≈70 Myr age. Stack averaging reveals CO emission in the starburst outer ring for the first time, but only where H i surface density (ΣH i) is high, representing {M}{{{H}}2}=(7.5+/- 0.8)× {10}8 M⊙ for a metallicity-appropriate αCO, giving small {{{Σ }}}{{{H}}2} (3.7 M⊙ pc-2), molecular fraction (fmol = 0.10), and H2 depletion timescales (τmol ≈ 50-600 Myr). Elsewhere in the outer ring {{{Σ }}}{{{H}}2}≲ 2 M⊙ pc-2, fmol ≲ 0.1 and τmol ≲ 140-540 Myr (all 3σ). The inner ring and nucleus are H2 dominated and are consistent with local spiral SF laws. ΣSFR in the outer ring appears independent of {{{Σ }}}{{{H}}2}, ΣH i, or {{{Σ }}}{{H} {{I}}+{{{H}}}2}. The ISM's long confinement in the robustly star-forming rings of the Cartwheel and AM0644-741 may result in either a large diffuse H2 component or an abundance of CO-faint low column density molecular clouds. The H2 content of evolved starburst rings may therefore be substantially larger. Due to its lower ΣSFR and age, the Cartwheel's inner ring has yet to reach this state. Alternately, the outer ring may trigger efficient SF in a H i-dominated ISM.

  7. MOLECULAR GAS AND STAR-FORMATION PROPERTIES IN THE CENTRAL AND BAR REGIONS OF NGC 6946

    SciTech Connect

    Pan, Hsi-An; Sorai, Kazuo; Kuno, Nario; Koda, Jin; Hirota, Akihiko; Kaneko, Hiroyuki

    2015-12-10

    In this work, we investigate the molecular gas and star-formation properties in the barred spiral galaxy NGC 6946 using multiple molecular lines and star-formation tracers. A high-resolution image (100 pc) of {sup 13}CO (1–0) is created for the inner 2 kpc disk by the single-dish Nobeyama Radio Observatory 45 m telescope and interferometer Combined Array for Research in Millimeter-wave Astronomy, including the central region (nuclear ring and bar) and the offset ridges of the primary bar. Single-dish HCN (1–0) observations were also made to constrain the amount of dense gas. The physical properties of molecular gas are inferred from (1) the large velocity gradient calculations using our observations and archival {sup 12}CO (1–0), {sup 12}CO(2–1) data, (2) the dense gas fraction suggested by the luminosity ratio of HCN to {sup 12}CO (1–0), and (3) the infrared color. The results show that the molecular gas in the central region is warmer and denser than that of the offset ridges. The dense gas fraction of the central region is similar to that of luminous infrared galaxies/ultraluminous infrared galaxies, whereas the offset ridges are close to the global average of normal galaxies. The coolest and least-dense region is found in a spiral-like structure, which was misunderstood to be part of the southern primary bar in previous low-resolution observations. The star-formation efficiency (SFE) changes by about five times in the inner disk. The variation of SFE agrees with the prediction in terms of star formation regulated by the galactic bar. We find a consistency between the star-forming region and the temperature inferred by the infrared color, suggesting that the distribution of subkiloparsec-scale temperature is driven by star formation.

  8. Evidence for Expulsion of the Star Formation Gas Reservoir by the AGN in Local Blue Ellipticals

    NASA Astrophysics Data System (ADS)

    Schwamb, Megan E.; Lintott, Chris; Smethurst, Rebecca; Kruk, Sandor; Matsushita, Satoki; Wong, Ivy; Wang, Shiang-Yu

    2016-01-01

    The formation and assembly of the local galaxy population remains a major open question. Recent works show that elliptical galaxies can rapidly transition from blue star forming to red quiescent systems. Such rapid reddening of stellar populations implies that gas reservoirs are being depleted on timescales which are much shorter than mere exhaustion thanks to ongoing star formation. Feedback, either from star formation itself or from nuclear activity associated with black hole growth is typically invoked. Yet observational confirmation has remained elusive.Using the 10.4-m CSO, we recently obtained 12CO(2-1) observations for a sample of blue star forming local elliptical galaxies to probe the state of the gas and look at the changes in excitation temperature across the star forming sequence. Previous IRAM 12CO(1-0) measurements indicate this population is undergoing a sudden decline in molecular gas fraction. This drop occurs ~200 Myr after a recent peak in star formation- a timescale suggesting AGN triggered feedback switches on rapidly and is immediately effective. The jets or outflows from the central supermassive black hole likely either heat or expel residual gas cutting off star formation, but the 12CO(1-0) measurements alone were insufficient to distinguish between these two scenarios. The 12CO(2-1) to 12CO(1-0) ratio has previously proved diagnostic of the conditions which exist in star forming galaxies. Combining the new 12CO(2-1) measurements with the previous 12CO(1-0) data, we find evidence for active quenching of star formation due to the expulsion of the gas reservoir by the central massive black holes residing in these galaxies. We will discuss our observations and analysis and compare our results to those from other early type populations.

  9. Angular Momentum Distribution of Hot Gas and Implications for Disk Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Chen, D. N.; Jing, Y. P.; Yoshikaw, Kohji

    2003-11-01

    We study the angular momentum profiles both for dark matter and for gas within virialized halos using a statistical sample of halos drawn from cosmological hydrodynamics simulations. Three simulations have been analyzed: one is the nonradiative simulation and the other two have radiative cooling. We find that the gas component, on average, has a larger spin and contains a smaller fraction of mass with negative angular momentum than its dark matter counterpart in the nonradiative model. As to the cooling models, the gas component shares approximately the same spin parameter as its dark matter counterpart, but the hot gas has a higher spin and is more aligned in angular momentum than dark matter, while the opposite holds for the cold gas. After the mass of negative angular momentum is excluded, the angular momentum profile of the hot gas component approximately follows the universal function originally proposed by Bullock et al. for dark matter, though the shape parameter μ is much larger for hot gas and is comfortably in the range required by observations of disk galaxies. Since disk formation is related to the distribution of hot gas that will cool, our study may explain the fact that the disk component of observed galaxies contains a smaller fraction of low angular momentum material than dark matter in halos.

  10. The Relationship Between Gas and Star Formation in the Magellanic Clouds

    NASA Astrophysics Data System (ADS)

    Jameson, Katherine; Bolatto, Alberto D.; Leroy, Adam K.; Meixner, Margaret; Roman-Duval, Julia; Gordon, Karl D.; Heritage Collaboration

    2015-01-01

    The low-mass, low-metallicity Magellanic Clouds provide ideal laboratories to study the physics of star formation at high resolution. We map the molecular gas distribution in the Large and Small Magellanic Clouds (LMC and SMC, respectively) by using the dust emission from HERITAGE Herschel data, which avoids the known biases of CO. Given the high resolution of the data (r˜20"˜5 pc for the LMC HERITAGE maps), we show the effect of convolving to resolutions up to r˜1 kpc and how the resolution differences compare to other studies of nearby galaxies. We find that the relationship between the molecular gas and star formation rate is consistent with studies of higher mass disk galaxies (i.e., Bigiel et al. 2011, Leroy et al. 2013), although the average molecular gas depletion time in the Magellanic Clouds may be shorter (~0.5 Gyr) than more massive, higher metallicity galaxies (typically ~2 Gyr). In the SMC, we find warm molecular gas fractions of ~10% using S4MC Spitzer IRS data of the rotational H2 lines, which is also consistent with higher mass, higher metallicity galaxies. Finally, we compare the total gas (atomic and molecular) and the star formation rate in the Magellanic Clouds to the model predictions from Krumholz (2013) and Ostriker, McKee, & Leroy (2010) and find that both models are consistent with the data.

  11. Grand Design and Flocculent Spiral Structure in Computer Simulations with Star Formation and Gas Heating

    NASA Astrophysics Data System (ADS)

    Elmegreen, B. G.; Thomasson, M.

    1993-05-01

    An algorithm for star formation and gas heating is included in numerical simulations of galaxy disks. With a high disk mass and an inner Q-barrier, the simulations spontaneously generate and then maintain for several revolutions a long-lived two-arm spiral wave mode that resembles a grand design galaxy. Eventually a multiple arm pattern appears because of a growing m = 3 component; multiple arm patterns also form right away if there is no Q barrier. When the stellar Q-value exceeds ~2.5 because of a low disk mass or a large velocity dispersion, stellar spirals do not form at all; if the relative gas mass is also small in this case (about 10 % of the total galaxy mass or less), then the spiral structure is purely flocculent, i.e., composed of numerous short arms in only the gas and star formation component. The star formation algorithm is made as realistic as possible, with young stars forming in virialized cloud complexes, moving kinematically as tracer particles, and heating their environments at the observed average rate. The results illustrate the importance for spiral structure of the stellar Q and the star formation thermostat in the interstellar gas.

  12. Hereditary hemorrhagic telangiectasia patient presenting with brain abscess due to silent pulmonary arteriovenous malformation.

    PubMed

    Themistocleous, Marios; Giakoumettis, Dimitrios; Mitsios, Andreas; Anagnostopoulos, Christos; Kalyvas, Aristoteles; Koutsarnakis, Christos

    2016-01-01

    Hereditary hemorrhagic telangiectasia is a rare autosomal dominant inherited disease that is usually complicated by visceral vascular malformations. Patients harboring such malformations are at increased risk of brain abscess formation, which despite advances in diagnostic and surgical methods remains a life threatening medical emergency with high mortality and morbidity rates. In the present report we describe a case of cerebral abscess due to silent pulmonary arteriovenous malformation (AVM) in a young patient previously undiagnosed for hereditary hemorrhagic telangiectasia syndrome (HHT).

  13. TOWARD A DETERMINISTIC MODEL OF PLANETARY FORMATION. VII. ECCENTRICITY DISTRIBUTION OF GAS GIANTS

    SciTech Connect

    Ida, S.; Lin, D. N. C.

    2013-09-20

    The ubiquity of planets and diversity of planetary systems reveal that planet formation encompasses many complex and competing processes. In this series of papers, we develop and upgrade a population synthesis model as a tool to identify the dominant physical effects and to calibrate the range of physical conditions. Recent planet searches have led to the discovery of many multiple-planet systems. Any theoretical models of their origins must take into account dynamical interactions between emerging protoplanets. Here, we introduce a prescription to approximate the close encounters between multiple planets. We apply this method to simulate the growth, migration, and dynamical interaction of planetary systems. Our models show that in relatively massive disks, several gas giants and rocky/icy planets emerge, migrate, and undergo dynamical instability. Secular perturbation between planets leads to orbital crossings, eccentricity excitation, and planetary ejection. In disks with modest masses, two or less gas giants form with multiple super-Earths. Orbital stability in these systems is generally maintained and they retain the kinematic structure after gas in their natal disks is depleted. These results reproduce the observed planetary mass-eccentricity and semimajor axis-eccentricity correlations. They also suggest that emerging gas giants can scatter residual cores to the outer disk regions. Subsequent in situ gas accretion onto these cores can lead to the formation of distant (∼> 30 AU) gas giants with nearly circular orbits.

  14. Fast laser-induced aerosol formation for visualization of gas flows

    NASA Technical Reports Server (NTRS)

    Hassa, C.; Hanson, R. K.

    1985-01-01

    A technique for aerosol seeding of gas flows by laser-induced particle formation is demonstrated using a pulsed Nd:YAG laser (1.06 microns) for optical breakdown of a mixture of SF6 and H2 in an inert carrier gas. It is noted that, contrary to the smoke-wire approach, the laser-induced particles form first in zones of high turbulence, since mixing enhances coagulation. The method also allows seeding to be performed in locations hardly accessible otherwise and is mechanically nonintrusive. Finally, a study of the mixture and the breakdown effects indicates that for H2:SF6 ratios between 3:1 and 15:1 the particle formation is only limited by the physics of the gas/particle conversion.

  15. Star Formation Rate and Gas Relations in the Arp 299 Merger from the VIXENS Survey

    NASA Astrophysics Data System (ADS)

    Heiderman, Amanda; Evans, Neal J.; Gebhardt, Karl; Blanc, Guillermo; Davis, Timothy; Papovich, Casey; van den Bosch, Remco; Iono, Daisuke; Yun, Min S.

    2015-08-01

    We highlight first results from the VIRUS-P Investigation of the eXtreme ENvironments of Starbursts (VIXENS) integral field unit survey. We investigate the relationship between star formation and gas content in late interaction phase merger Arp 299 from VIXENS. By comparing Hα, Paα, and 24μm images to CO(2→1), CO(3→2), HCN(1→0), HCO+(1→0), and HI maps, we explore the relation between the star formation rate and gas surface densities on spatially resolved ~kpc scales. We find that the SFR-gas relations for Arp 299 are discrepant from known extragalactic spatially resolved relations in nearby spiral galaxies and disk-averaged relations in high-z mergers.

  16. Residue formations of phosphorus hydride polymers and phosphorus oxyacids during phosphine gas fumigations of stored products.

    PubMed

    Flora, Jason W; Byers, Loran E; Plunkett, Susan E; Faustini, Daryl L

    2006-01-11

    With the extent of international usage and the critical role phosphine gas (PH3) plays in commercial pest control, identification of the residual components deposited during fumigation is mandatory. It has been postulated that these infrequent residues are primarily composed of phosphoric acid or reduced forms of phosphoric acid [hypophosphorous acid (H3PO2) and phosphorous acid (H3PO3)], due to the oxidative degradation of phosphine. Using environmental scanning electron microscopy, gas phase Fourier transform infrared spectroscopy, and X-ray fluorescence spectroscopy, the structural elucidation and formation mechanism of the yellow amorphous polyhydric phosphorus polymers (P(x)H(y)) that occur in addition to the lower oxyacids of phosphorus in residues deposited during PH3 fumigations of select tobacco commodities are explored. This research determined that nitric oxide gas (or nitrogen dioxide) initiates residue formation of phosphorus hydride polymers and phosphorus oxyacids during PH3 fumigations of stored products.

  17. Evaluation of the geological relationships to gas hydrate formation and stability

    SciTech Connect

    Not Available

    1986-01-01

    Although there are many publications pertaining to gas hydrates, their formation and stability in various geological conditions are poorly known. Therefore, for the same reasons and because of the very broad scope of our research, limited amount and extremely dispersed information, the study regions are very large. Moreover, almost without exception the geological environments controlling gas hydrates formation and stability of the studied regions are very complex. The regions studied (completed and partially completed - total 17 locations) during the reporting period, particularly the Gulf of Mexico and the Middle America Trench, are the most important in this entire research project. In the past, both of these regions have been extensively studied, the presence of gas hydrates confirmed and samples recovered. In our investigation it was necessary not only to review all previous data and interpretations, but to do a thorough analysis of the basins, and a critical evaluation of an previously reported and publicly available but not published information.

  18. Lung abscess-etiology, diagnostic and treatment options

    PubMed Central

    Kuhajda, Ivan; Zarogoulidis, Konstantinos; Tsirgogianni, Katerina; Tsavlis, Drosos; Kioumis, Ioannis; Kosmidis, Christoforos; Tsakiridis, Kosmas; Mpakas, Andrew; Zissimopoulos, Athanasios; Baloukas, Dimitris; Kuhajda, Danijela

    2015-01-01

    Lung abscess is a type of liquefactive necrosis of the lung tissue and formation of cavities (more than 2 cm) containing necrotic debris or fluid caused by microbial infection. It can be caused by aspiration, which may occur during altered consciousness and it usually causes a pus-filled cavity. Moreover, alcoholism is the most common condition predisposing to lung abscesses. Lung abscess is considered primary (60%) when it results from existing lung parenchymal process and is termed secondary when it complicates another process, e.g., vascular emboli or follows rupture of extrapulmonary abscess into lung. There are several imaging techniques which can identify the material inside the thorax such as computerized tomography (CT) scan of the thorax and ultrasound of the thorax. Broad spectrum antibiotic to cover mixed flora is the mainstay of treatment. Pulmonary physiotherapy and postural drainage are also important. Surgical procedures are required in selective patients for drainage or pulmonary resection. In the current review we will present all current information from diagnosis to treatment. PMID:26366400

  19. Clinical characteristics and progression of liver abscess caused by toxocara

    PubMed Central

    Ha, Kyung Ho; Song, Jung Eun; Kim, Byung Seok; Lee, Chang Hyeong

    2016-01-01

    AIM: To evaluate the clinical characteristics and progression of liver abscess caused by toxocara. METHODS: We retrospectively reviewed the medical records of patients with serum IgG antibody to Toxocara canis and liver abscess diagnosed using abdominal computed tomography between February 2010 and February 2015. Among 84 patients exhibiting serum IgG antibody to Toxocara canis, 34 patients were diagnosed with liver asbscess and treated with albendazole. A follow-up period of 1 year was conducted. RESULTS: Mean patient age was 53 (34-79) years, with 26 (76.5%) patients being male. Twenty-one (61.7%) patients were moderate or heavy drinkers, 23 (67.6%) patients had a history of eating raw meat or liver and 6 (17.6%) patients owned pet dogs or cats. Main patient symptoms consisted of right upper quadrant pain, fever, and fatigue; 18 (52.9%) patients, however, presented with no symptoms. Lung involvement was detected in 444 (11.7%) patients. The eosinophil count increased in 29 (85.3%) patients at initial diagnosis, and decreased in most patients after albendazole treatment. The initial serum IgE level increased in 25 (73.5%) patients, but exhibited various response levels after albendazole treatment. Liver abscess formation improved in all patients. CONCLUSION: The liver abscess was improved with albendazole treatment. PMID:27366302

  20. DETECTION OF MOLECULAR GAS IN VOID GALAXIES: IMPLICATIONS FOR STAR FORMATION IN ISOLATED ENVIRONMENTS

    SciTech Connect

    Das, M.; Honey, M.; Saito, T.; Iono, D.; Ramya, S.

    2015-12-10

    We present the detection of molecular gas from galaxies located in nearby voids using the CO(1–0) line emission as a tracer. The observations were performed using the 45 m single dish radio telescope of the Nobeyama Radio Observatory. Void galaxies lie in the most underdense parts of our universe and a significant fraction of them are gas rich, late-type spiral galaxies. Although isolated, they have ongoing star formation but appear to be slowly evolving compared to galaxies in denser environments. Not much is known about their star formation properties or cold gas content. In this study, we searched for molecular gas in five void galaxies. The galaxies were selected based on their relatively high IRAS fluxes or Hα line luminosities, both of which signify ongoing star formation. All five galaxies appear to be isolated and two lie within the Bootes void. We detected CO(1–0) emission from four of the five galaxies in our sample and their molecular gas masses lie between 10{sup 8} and 10{sup 9} M{sub ⊙}. We conducted follow-up Hα imaging observations of three detected galaxies using the Himalayan Chandra Telescope and determined their star formation rates (SFRs) from their Hα fluxes. The SFR varies from 0.2 to 1 M{sub ⊙} yr{sup −1}; which is similar to that observed in local galaxies. Our study indicates that although void galaxies reside in underdense regions, their disks contain molecular gas and have SFRs similar to galaxies in denser environments. We discuss the implications of our results.

  1. Formation of the Giant Planets by Concurrent Accretion of Solids and Gas

    NASA Technical Reports Server (NTRS)

    Hubickyj, Olenka

    1997-01-01

    Models were developed to simulate planet formation. Three major phases are characterized in the simulations: (1) planetesimal accretion rate, which dominates that of gas, rapidly increases owing to runaway accretion, then decreases as the planet's feeding zone is depleted; (2) occurs when both solid and gas accretion rates are small and nearly independent of time; and (3) starts when the solid and gas masses are about equal and is marked by runaway gas accretion. The models applicability to planets in our Solar System are judged using two basic "yardsticks". The results suggest that the solar nebula dissipated while Uranus and Neptune were in the second phase, during which, for a relatively long time, the masses of their gaseous envelopes were small but not negligible compared to the total masses. Background information, results and a published article are included in the report.

  2. Formation of an out-of-electrode plasma in a high-voltage gas discharge

    NASA Astrophysics Data System (ADS)

    Kolpakov, V. A.; Kolpakov, A. I.; Podlipnov, V. V.

    2013-04-01

    The formation of an out-of-electrode plasma in a high-voltage gas discharge is studied. The occurrence and self-maintenance of a gas discharge and its associated plasma fluxes on the straight portions of electrical field lines are predicted theoretically and confirmed experimentally. It is shown that the focusing of the gas discharge and plasma fluxes is provided by increasing the length of the field line straight portions toward the symmetry axis of a hole in the anode. It is found that, when the discharge power (more specifically, an accelerating voltage applied to the electrodes of the gas-discharge tube) rises, the straight portions of the field lines elongate and concentrate near the symmetry axis of the hole in the anode. Recommendations are given on using the out-of-electrode plasma in surface micro- and nanostructuring.

  3. Multifunctional acid formation from the gas-phase ozonolysis of beta-pinene.

    PubMed

    Ma, Yan; Marston, George

    2008-10-28

    The gas-phase ozonolysis of beta-pinene was studied in static chamber experiments, using gas chromatography coupled to mass spectrometric and flame ionisation detection to separate and detect products. A range of multifunctional organic acids-including pinic acid, norpinic acid, pinalic-3-acid, pinalic-4-acid, norpinalic acid and OH-pinalic acid-were identified in the condensed phase after derivatisation. Formation yields for these products under systematically varying reaction conditions (by adding different OH radical scavengers and Criegee intermediate scavengers) were investigated and compared with those observed from alpha-pinene ozonolysis, allowing detailed information on product formation mechanisms to be elucidated. In addition, branching ratios for the initial steps of the reaction were inferred from quantitative measurements of primary carbonyl formation. Atmospheric implications of this work are discussed.

  4. Stripping out pus in lactational mastitis: a means of preventing breast abscess.

    PubMed Central

    Bertrand, H; Rosenblood, L K

    1991-01-01

    OBJECTIVE: To determine whether manual stripping of pus from the breasts of women with lactational mastitis is effective in preventing the formation of breast abscesses. DESIGN: Case series (chart review). SETTING: Family practice in Montreal. PATIENTS: All (475) charts of patients with lactational mastitis were reviewed; 61 women were excluded because they already had a breast abscess. Most of the patients had been referred. OUTCOME MEASURES: Abscess formation, length of illness after treatment, rate of recurrence of mastitis, illness in the mother or infant within the 6 weeks after the mastitis and continuance of breast-feeding. MAIN RESULTS: The duration of symptoms before treatment was 1 to 56 (mean 5.3) days. In 9% of the cases both breasts were affected, and in 23% at least one episode of mastitis had previously occurred. The stripping technique was applied to all the patients. Pus was removed in 210 women; the remaining women were considered to have cellulitis. Only four patients (less than 1%) had breast abscesses. The mean length of illness after treatment was 7.2 days. The rate of recurrence was 14%. In all, 6% of the mothers and 9% of the infants became ill in the 6 weeks after the mastitis. Most (92%) of the patients continued to breast-feed. CONCLUSIONS: The rate of abscess formation was considerably lower than the rates reported in the literature. Therefore, manual stripping of pus from the infected breasts of lactating women appears to be effective in preventing breast abscesses. PMID:1873763

  5. The rising star formation histories of distant galaxies and implications for gas accretion with time

    NASA Astrophysics Data System (ADS)

    Papovich, Casey; Finkelstein, Steven L.; Ferguson, Henry C.; Lotz, Jennifer M.; Giavalisco, Mauro

    2011-04-01

    Distant galaxies show correlations between their current star formation rates (SFRs) and stellar masses, implying that their star formation histories (SFHs) are highly similar. Moreover, observations show that the ultraviolet luminosities and stellar masses grow from z= 8 to 3, implying that the SFRs increase with time. We compare the cosmologically averaged evolution in galaxies at 3 < z < 8 at constant comoving number density, n= 2 × 10-4 Mpc-3. This allows us to study the evolution of stellar mass and star formation in the galaxy predecessors and descendants in ways not possible using galaxies selected at constant stellar mass or SFR, quantities that themselves evolve strongly in time. We show that the cosmologically averaged SFRs of these galaxies increase smoothly from z= 8 to 3 as Ψ(t) ˜tα with α= 1.7 ± 0.2. This conflicts with assumptions that the SFR is either constant or declines exponentially in time. Furthermore, we show that the stellar mass growth in these galaxies is consistent with this derived SFH. This provides evidence that the slope of the high-mass end of the initial mass function is approximately Salpeter unless the duty cycle of star formation is much less than unity. We argue that these relations follow from gas accretion (either through accretion or delivered by mergers) coupled with galaxy disc growth under the assumption that the SFR depends on the local gas surface density. This predicts that gas fractions decrease from z= 8 to 3 on average as fgas˜ (1 +z)0.9 for galaxies with this number density. The implied galaxy gas accretion rates at z > 4 are as fast and may even exceed the SFR: this is the ‘gas accretion epoch’. At z < 4 the SFR overtakes the implied gas accretion rate, indicating a period where galaxies consume gas faster than it is acquired. At z≲ 3, galaxies with this number density depart from these relations implying that star formation and gas accretion are slowed at later times.

  6. Wintertime Air Quality Impacts from Oil and Natural Gas Drilling Operations in the Bakken Formation Region

    NASA Astrophysics Data System (ADS)

    Evanoski-Cole, Ashley; Sive, Barkley; Zhou, Yong; Prenni, Anthony; Schurman, Misha; Day, Derek; Sullivan, Amy; Li, Yi; Hand, Jenny; Gebhart, Kristi; Schichtel, Bret; Collett, Jeffrey

    2016-04-01

    Oil and natural gas extraction has dramatically increased in the last decade in the United States due to the increased use of unconventional drilling techniques which include horizontal drilling and hydraulic fracturing. The impact of these drilling activities on local and regional air quality in oil and gas basins across the country are still relatively unknown, especially in recently developed basins such as the Bakken shale formation. This study is the first to conduct a comprehensive characterization of the regional air quality in the Bakken region. The Bakken shale formation, part of the Williston basin, is located in North Dakota and Montana in the United States and Saskatchewan and Manitoba in Canada. Oil and gas drilling operations can impact air quality in a variety of ways, including the generation of atmospheric particulate matter (PM), hazardous air pollutants, ozone, and greenhouse gas emissions. During the winter especially, PM formation can be enhanced and meteorological conditions can favor increased concentrations of PM and other pollutants. In this study, ground-based measurements throughout the Bakken region in North Dakota and Montana were collected over two consecutive winters to gain regional trends of air quality impacts from the oil and gas drilling activities. Additionally, one field site had a comprehensive suite of instrumentation operating at high time resolution to gain detailed characterization of the atmospheric composition. Measurements included organic carbon and black carbon concentrations in PM, the characterization of inorganic PM, inorganic gases, volatile organic compounds (VOCs), precipitation and meteorology. These elevated PM episodes were further investigated using the local meteorological conditions and regional transport patterns. Episodes of elevated concentrations of nitrogen oxides and sulfur dioxide were also detected. The VOC concentrations were analyzed and specific VOCs that are known oil and gas tracers were used

  7. Effect of peripheral temperature on the formation of venous gas bubbles.

    PubMed

    Mekjavić, I B; Kakitsuba, N

    1989-09-01

    Temperature of the tissue affects the many components involved in the formation of tissue gas phase formation: diffusion, perfusion, and inert gas solubility. Since the effects of perfusion and inert gas solubility may be counteracting in terms of enhancing growth of gas bubbles, the optimal thermal status of divers throughout a dive remains unresolved. To elucidate the role of peripheral body temperature on gas phase formation, four subjects were exposed to a 10 degree and 40 degree C environment for 3 h on two separate occasions, after a no-stop decompression from a 12-h dive to 9.14 m (30 fsw) on air. The 3-hour exposures to either a cold or warm air environment resulted in a significant difference in mean skin temperature (P less than or equal to 0.01) with no alteration in rectal temperature. Total peripheral resistance during the 10 degree C exposure was 13.8 +/- 1.9 mmHg.liter-1.min-1 and significantly higher than that observed during the 40 degree C exposure (10.4 +/- 3.5 mmHg.liter-1.min-1). Gas bubbles in the venous return were monitored with a Doppler ultrasonic transducer placed in the precordial region, both at rest and after a deep knee bend. Venous bubbles were only detected in 1 subject following the warm air exposure, whereas 3 of the 4 subjects developed Doppler-detectable bubbles during the cold air exposure. Although both the cold and warm air exposures (3 h postdecompression) were uneventful, a hot shower taken by the subjects on completion of the cold air exposure (6 h postdecompression) precipitated mild type I symptoms of decompression sickness. These symptoms were not present after a hot shower following the warm air exposure. The present results indicate that despite the assumed greater inert gas solubility of tissues expected during cold air exposure, the decrease in the perfusion may have played a more significant role in the observed levels of detectable venous gas bubbles. Development of type I symptoms following a 12-h saturation, a 3

  8. Quantifying Hydrate Formation in Gas-rich Environments Using the Method of Characteristics

    NASA Astrophysics Data System (ADS)

    You, K.; Flemings, P. B.; DiCarlo, D. A.

    2015-12-01

    Methane hydrates hold a vast amount of methane globally, and have huge energy potential. Methane hydrates in gas-rich environments are the most promising production targets. We develop a one-dimensional analytical solution based on the method of characteristics to explore hydrate formation in such environments (Figure 1). Our solution shows that hydrate saturation is constant with time and space in a homogeneous system. Hydrate saturation is controlled by the initial thermodynamic condition of the system, and changed by the gas fractional flow. Hydrate saturation increases with the initial distance from the hydrate phase boundary. Different gas fractional flows behind the hydrate solidification front lead to different gas saturations at the hydrate solidification front. The higher the gas saturation at the front, the less the volume available to be filled by hydrate, and hence the lower the hydrate saturation. The gas fractional flow depends on the relative permeability curves, and the forces that drive the flow. Viscous forces (the drive for flow induced from liquid pressure gradient) dominate the flow, and hydrate saturation is independent on the gas supply rates and the flow directions at high gas supply rates. Hydrate saturation can be estimated as one minus the ratio of the initial to equilibrium salinity. Gravity forces (the drive for flow induced from the gravity) dominate the flow, and hydrate saturation depends on the flow rates and the flow directions at low gas supply rates. Hydrate saturation is highest for upward flow, and lowest for downward flow. Hydrate saturation decreases with the flow rate for upward flow, and increases with the flow rate for downward flow. This analytical solution illuminates how hydrate is formed by gas (methane, CO2, ethane, propane) flowing into brine-saturated sediments at both the laboratory and geological scales (Figure 1). It provides an approach to generalize the understanding of hydrate solidification in gas

  9. Facies, faults and potential sweet spots in a tight gas reservoir: Almond Formation, Wyoming

    SciTech Connect

    Martinsen, R.; Iverson, W.; Surdam, R.

    1996-12-31

    The Almond Formation is a major producer of gas in southwestern Wyoming. Although exploration generally is aimed at finding conventional reservoirs in upper Almond marine sandstones, the majority of Almond gas is contained in the underlying main Almond, a succession of dominantly non-marine, interbedded tight sandstones, siltstones, carbonaceous shales and coals. Production data indicate that some of the best gas wells completed in upper Almond sands show little production decline and have already produced more gas than calculations indicate they contain. This implies that these wells have somehow successfully tapped into the vast supply of gas contained in the main Almond. We believe that the more permeable reservoirs, in addition to providing {open_quotes}sweet spots{close_quotes} for exploration, also serve as lateral conduits capable of draining gas over a broad area from the main Almond. The {open_quotes}sweet spots{close_quotes} themselves do not need to be volumetrically large, only permeable and laterally continuous. Previously unrecognized marine sands, similar to those in the upper Almond, are favorably located in the middle of the main Almond succession and may provide additional lateral conduits. Studies also show that syndepositional faults significantly influenced deposition and may also be important in terms of fluid flow. At least some syndepositional faults are associated with anomalously high gas and/or water production within fields, and may be vertical conduits for fluid flow.

  10. Facies, faults and potential sweet spots in a tight gas reservoir: Almond Formation, Wyoming

    SciTech Connect

    Martinsen, R.; Iverson, W.; Surdam, R. )

    1996-01-01

    The Almond Formation is a major producer of gas in southwestern Wyoming. Although exploration generally is aimed at finding conventional reservoirs in upper Almond marine sandstones, the majority of Almond gas is contained in the underlying main Almond, a succession of dominantly non-marine, interbedded tight sandstones, siltstones, carbonaceous shales and coals. Production data indicate that some of the best gas wells completed in upper Almond sands show little production decline and have already produced more gas than calculations indicate they contain. This implies that these wells have somehow successfully tapped into the vast supply of gas contained in the main Almond. We believe that the more permeable reservoirs, in addition to providing [open quotes]sweet spots[close quotes] for exploration, also serve as lateral conduits capable of draining gas over a broad area from the main Almond. The [open quotes]sweet spots[close quotes] themselves do not need to be volumetrically large, only permeable and laterally continuous. Previously unrecognized marine sands, similar to those in the upper Almond, are favorably located in the middle of the main Almond succession and may provide additional lateral conduits. Studies also show that syndepositional faults significantly influenced deposition and may also be important in terms of fluid flow. At least some syndepositional faults are associated with anomalously high gas and/or water production within fields, and may be vertical conduits for fluid flow.

  11. New Natural Gas Storage and Transportation Capabilities Utilizing Rapid Methane Hydrate Formation Techniques

    SciTech Connect

    Brown, T.D.; Taylor, C.E.; Bernardo, M.

    2010-01-01

    Natural gas (methane as the major component) is a vital fossil fuel for the United States and around the world. One of the problems with some of this natural gas is that it is in remote areas where there is little or no local use for the gas. Nearly 50 percent worldwide natural gas reserves of ~6,254.4 trillion ft3 (tcf) is considered as stranded gas, with 36 percent or ~86 tcf of the U.S natural gas reserves totaling ~239 tcf, as stranded gas [1] [2]. The worldwide total does not include the new estimates by U.S. Geological Survey of 1,669 tcf of natural gas north of the Arctic Circle, [3] and the U.S. ~200,000 tcf of natural gas or methane hydrates, most of which are stranded gas reserves. Domestically and globally there is a need for newer and more economic storage, transportation and processing capabilities to deliver the natural gas to markets. In order to bring this resource to market, one of several expensive methods must be used: 1. Construction and operation of a natural gas pipeline 2. Construction of a storage and compression facility to compress the natural gas (CNG) at 3,000 to 3,600 psi, increasing its energy density to a point where it is more economical to ship, or 3. Construction of a cryogenic liquefaction facility to produce LNG, (requiring cryogenic temperatures at <-161 °C) and construction of a cryogenic receiving port. Each of these options for the transport requires large capital investment along with elaborate safety systems. The Department of Energy's Office of Research and Development Laboratories at the National Energy Technology Laboratory (NETL) is investigating new and novel approaches for rapid and continuous formation and production of synthetic NGHs. These synthetic hydrates can store up to 164 times their volume in gas while being maintained at 1 atmosphere and between -10 to -20°C for several weeks. Owing to these properties, new process for the economic storage and transportation of these synthetic hydrates could be envisioned

  12. Iliopsoas abscess masquerading as 'sciatica'.

    PubMed

    Shields, D W; Robinson, Patrick G

    2012-12-20

    A 35-year-old woman of Indian origin presented with a 5-month history of lower back pain, radiating down the back of her right leg in distribution of the sciatic nerve. Referral was made to the spinal clinic querying sciatica, but a deterioration in her symptoms developed, and the patient presented to the Accident and Emergency department. She was significantly tender at right sacroiliac joint and had positive psoas sign. The MRI scan showed a large iliopsoas abscess causing bony destruction, and extended culture was positive for mycobacterium tuberculosis. The patient was initially diagnosed with sciatica yet had a positive psoas sign and a painful sacrum. It is important that primary physicians are aware of the relations the iliopsoas muscle and the potential effect an abscess can have here. A sinister underlying cause of a patient's sciatic distribution of pain should be excluded before accepting a diagnosis of mechanical back pain.

  13. Brain abscess of odontogenic origin.

    PubMed

    Antunes, Antonio Azoubel; de Santana Santos, Thiago; de Carvalho, Ricardo Wathson Feitosa; Avelar, Rafael Linard; Pereira, Carlos Umberto; Pereira, José Carlos

    2011-11-01

    Brain abscess is a rare and threatening infection, which is in a suppuration area, caused either by trauma, neurosurgical complication, or by a secondary infection of dental origin complication. The infectious process spread from the start focus can occur in 2 ways: hematogenous or by contiguity. The treatment should ideally be based on the etiological factor excision, combined with drainage and antibiotics as adjuvant; this philosophy is not observed in the reports described in the 1960s, 1970s, and 1980s. This study's goal was to report a case of brain abscess consequent of an odontogenic outbreak, where an adequate treatment was set up, but it was already in advanced stages and had as a result the lethal outcome. Complications from the odontogenic infections have a low incidence, but should never be disregarded, because they can lead to death, as described in this manuscript.

  14. Retroperitoneal abscesses in seven dogs.

    PubMed

    Marvel, Sarah J; MacPhail, Catriona M

    2013-01-01

    Retroperitoneal abscesses, although uncommon, are clinically important. Medical records of seven dogs with naturally occurring retroperitoneal infections from 1999 to 2011 were reviewed to document historical, examination, clinicopathologic, imaging, and surgical findings; etiologic agents; and outcome. Middle-aged sporting dogs were most commonly affected. Dogs were febrile with evidence of either abdominal or lumbar pain. Although traditional radiography can aid in diagnosis, ultrasound appeared to be a more sensitive indicator of disease within the retroperitoneal space. Numerous bacteria were isolated from the abscesses, with anaerobic and facultative anaerobic bacteria being the most commonly isolated. Etiology was largely unknown, but migrating plant material was often suspected. Resolution of the infection required surgical intervention as well as prolonged antibiotic therapy. Although recurrence is possible, outcome can be favorable with no long-term sequela.

  15. Experimental evidence of nitrous acid formation in the electron beam treatment of flue gas

    NASA Astrophysics Data System (ADS)

    Mätzing, H.; Namba, H.; Tokunaga, O.

    1994-03-01

    In the Electron Beam Dry Scrubbing (EBDS) process, flue gas from fossil fuel burning power plants is irradiated with accelerated (300-800 keV) electrons. Thereby, nitrogen oxide (NO x) and sulfur dioxide (SO 2) traces are transformed into nitric and sulfuric acids, respectively, which are converted into particulate ammonium nitrate and sulfate upon the addition of ammonia. The powdery can be filtered from the main gas stream and can be sold as agricultural fertilizer. A lot of experimental investigations have been performed on the EBDS process and computer models have been developed to interpret the experimental results and to predict economic improvements. According to the model calculations, substantial amounts of intermediate nitrous acid (HNO 2) are formed in the electron beam treatment of flue gas. However, no corresponding experimental information is available so far. Therefore, we have undertaken the first experimental investigation about the formation of nitrous acid in an irradiated mixture of NO in synthetic air. Under these conditions, aerosol formation is avoided. UV spectra of the irradiated gas were recorded in the wavelength range λ = 345-375 nm. Both NO 2 and HNO 2 have characteristic absorption bands in this wavelength range. Calibration spectra of NO 2 were subtracted from the sample spectra. The remaining absorption bands can clearly be assigned to nitrous acid. The concentration of nitrous acid was determined by differential optical absorption. It was found lower than the model prediction. The importance of nitrous acid formation in the EBDS process needs to be clarified.

  16. A Universal Correlation between Star Formation Activity and Molecular Gas Properties Across Environments

    NASA Astrophysics Data System (ADS)

    Koyama, Shuhei; Koyama, Yusei; Yamashita, Takuji; Morokuma-Matsui, Kana; Matsuhara, Hideo; Nakagawa, Takao; Hayashi, Masao; Kodama, Tadayuki; Shimakawa, Rhythm; Suzuki, Tomoko L.; Tadaki, Ken-ichi; Tanaka, Ichi; Yamamoto, Moegi

    2017-10-01

    We present the molecular gas mass fraction ({f}{{{H}}2}) and star formation efficiency (SFE) of local galaxies on the basis of our new CO(J=1-0) observations with the Nobeyama 45 m radio telescope, combined with the COLDGASS galaxy catalog, as a function of galaxy environment defined as the local number density of galaxies measured with SDSS DR7 spectroscopic data. Our sample covers a wide range in the stellar mass and star formation rate (SFR), and also covers a wide environmental range over two orders of magnitude. This allows us to conduct the first systematic study of environmental dependence of molecular gas properties in galaxies from the lowest- to the highest-density environments in the local universe. We confirm that both {f}{{{H}}2} and SFE have strong positive correlations with the SFR offset from the star-forming main sequence (ΔMS) and, most importantly, we find that these correlations are universal across all environments. Our result demonstrates that star formation activity within individual galaxies is primarily controlled by their molecular gas content, regardless of their global environment. Therefore, we claim that one always needs to be careful about the ΔMS distribution of the sample when investigating the environmental effects on the H2 gas content in galaxies.

  17. Orbital Stability of Protoplanetary Systems in Nebular Gas and Implications for Terrestrial Planet Formation

    NASA Astrophysics Data System (ADS)

    Iwasaki, Kazunori; Ohtsuki, Keiji

    2006-06-01

    The oligarchic growth model of planetary accretion predicts the formation of protoplanets of similar sizes, and the final stage of terrestrial planet formation involves long-term orbital instability and mutual collision of protoplanets through their gravitational interaction. However, the mass of the protoplanets formed by oligarchic growth depends on the initial surface density of the protoplanetary disk, as well as the distance from the central star. In order to better understand the final stage of terrestrial planet formation in disks with various profiles, we perform orbital integration for systems of five protoplanets and examine the dependence of the orbital instability timescale of the systems on the mass of the protoplanets, Mp, both with and without nebular gas. Previous studies have shown that the timescale for orbital instability in the absence of nebular gas increases exponentially with the initial semimajor axis difference between the protoplanets. We find that the exponential constant is independent of the mass of the protoplanets, as long as the initial separation is measured in units of ~M0.29p, which is very close to the previously derived mass dependence of the critical separation for the onset of chaotic behavior in the restricted circular three-body problem. In the presence of nebular gas, on the other hand, protoplanetary systems are stabilized by gas drag and experience no orbital instability when the initial semimajor axis difference is larger than a certain critical value. Using these results, we discuss the orbital stability of protoplanetary systems in disks with various surface densities.

  18. Effects of flue gas compositions on nitrosamine and nitramine formation in postcombustion CO2 capture systems.

    PubMed

    Dai, Ning; Mitch, William A

    2014-07-01

    Amine-based technologies are emerging as the prime contender for postcombustion CO2 capture. However, concerns have arisen over the health impacts of amine-based CO2 capture associated with the release of nitrosamines and nitramines, which are byproducts from the reactions between flue gas NOx and solvent amines. In this study, flue gas compositions were systematically varied to evaluate their effects on the formation of nitrosamines and nitramines in a lab-scale CO2 capture reactor with morpholine as a model solvent amine. The accumulation of N-nitrosomorpholine in both the absorber and washwater increased linearly with both NO and NO2 for concentrations up to ∼20 ppmv. These correlations could be extrapolated to estimate N-nitrosomorpholine accumulation at extremely low NOx levels (0.3 ppmv NO2 and 1.5 ppmv NO). NO played a particularly important role in driving N-nitrosomorpholine formation in the washwater, likely following partial oxidation to NO2 by O2. The accumulation of N-nitromorpholine in both the absorber and washwater positively correlated with flue gas NO2 concentration, but not with NO concentration. Both N-nitrosomorpholine and N-nitromorpholine accumulated fastest in the absence of CO2. Flue gas humidity did not affect nitrosamine accumulation in either the absorber or the washwater unit. These results provide a basis for estimating the effects of flue gas composition on nitrosamine and nitramine accumulation in postcombustion CO2 capture systems.

  19. Computational Approach for Gas Hydrate Formation and Corresponding Physical Property Changes

    NASA Astrophysics Data System (ADS)

    Hu, D.; Keehm, Y.

    2008-12-01

    Gas hydrate is a solid substance composed of water and hydrocarbon (mainly methane). It occurs worldwide in the oceanic and polar sediments where temperature is low enough and pressure is sufficiently high to crystallize the methane into gas hydrate. Gas hydrate has drawn great attention because it can be future energy resource, a global warming factor and a hazard in ocean structures such as oil platforms. However, the formation of gas hydrate and corresponding physical property changes are not well known, since the detailed hydrates formation mechanism at the pore scale are poorly understood. In this paper, we try various phenomenological formation models on pore microstructure of beach sands obtained by the X-ray microtomographic technique, and calculate physical properties of hydrate-bearing sediments as functions of gas hydrate saturation. Then we compare the results to lab experiments by KIGAM (Korea Institute of Geoscience and Mineral Resources) and AIST (Advanced Industrial Science and Technology of Japan), which were obtained from a similar experiment setup, but the permeability trends along hydrate saturation were quite different. As a preliminary result, among the various nucleation and growth models, the KIGAM's results agree well with G-2 model, where the nucleation and growth of hydrate occur at the pore throats; while AIST's results seem to match the G-3 model, which is growth-dominant one. Although more complete conclusion will be possible by more results from ongoing pore-scale modeling, this computational approach show that it can be a robust tool for analyzing the hydrate formation mechanism for a given sediment and estimating quantitative relations between hydrate saturation and physical properties of hydrate-bearing sediments.

  20. Comparison of different gas-phase mechanisms and aerosol modules for simulating particulate matter formation.

    PubMed

    Kim, Youngseob; Couvidat, Florian; Sartelet, Karine; Seigneur, Christian

    2011-11-01

    The effects of two gas-phase chemical kinetic mechanisms, Regional Atmospheric Chemistry Mechanism version 2 (RACM2) and Carbon-Bond 05 (CB05), and two secondary organic aerosol (SOA) modules, the Secondary Organic Aerosoi Model (SORGAM) and AER/EPRI/Caltech model (AEC), on fine (aerodynamic diameter < or =2.5 microm) particulate matter (PM2.5) formation is studied. The major sources of uncertainty in the chemistry of SOA formation are investigated. The use of all major SOA precursors and the treatment of SOA oligomerization are found to be the most important factors for SOA formation, leading to 66% and 60% more SOA, respectively. The explicit representation of high-NO, and low-NOx gas-phase chemical regimes is also important with increases in SOA of 30-120% depending on the approach used to implement the distinct SOA yields within the gas-phase chemical kinetic mechanism; further work is needed to develop gas-phase mechanisms that are fully compatible with SOA formation algorithms. The treatment of isoprene SOA as hydrophobic or hydrophilic leads to a significant difference, with more SOA being formed in the latter case. The activity coefficients may also be a major source of uncertainty, as they may differ significantly between atmospheric particles, which contain a myriad of SOA, primary organic aerosol (POA), and inorganic aerosol species, and particles formed in a smog chamber from a single precursor under dry conditions. Significant interactions exist between the uncertainties of the gas-phase chemistry and those of the SOA module.

  1. Changing etiology of iliopsoas abscess.

    PubMed

    Walsh, T R; Reilly, J R; Hanley, E; Webster, M; Peitzman, A; Steed, D L

    1992-04-01

    Over a 5-year period, iliopsoas abscesses were found in 11 patients. Although the most common underlying condition was Crohn's disease (3 of 11 patients), 5 abscesses resulted from hematogenous spread from a distant site. Each of these five patients was elderly, severely malnourished, or had an underlying chronic disease. Fever was a presenting sign in 8 of 11 patients, whereas all 4 patients who presented with back pain had nontuberculous lumbar osteomyelitis or disk space infections. No patient presented with the classic triad of fever, back pain, and anterior thigh or groin pain. Computed tomographic (CT) scans accurately established the clinical diagnosis in 10 of 11 patients. Two of the patients died. One patient was an intravenous drug abuser, whereas the other patient was being treated with steroids for systemic lupus erythematosus. Elderly patients, diabetics, and patients with chronic disease are susceptible to this kind of occult infection and may present with minimal clinical findings. Aggressive diagnosis using CT scanning and treatment with resection of involved bowel, complete drainage of the abscess, and prolonged antibiotics are required to salvage these patients.

  2. On the formation of hydrogen gas on copper in anoxic water.

    PubMed

    Johansson, Adam Johannes; Lilja, Christina; Brinck, Tore

    2011-08-28

    Hydrogen gas has been detected in a closed system containing copper and pure anoxic water [P. Szakalos, G. Hultquist, and G. Wikmark, Electrochem. Solid-State Lett. 10, C63 (2007) and G. Hultquist, P. Szakalos, M. Graham, A. Belonoshko, G. Sproule, L. Grasjo, P. Dorogokupets, B. Danilov, T. Aastrup, G. Wikmark, G. Chuah, J. Eriksson, and A. Rosengren, Catal. Lett. 132, 311 (2009)]. Although bulk corrosion into any of the known phases of copper is thermodynamically forbidden, the present paper shows how surface reactions lead to the formation of hydrogen gas in limited amounts. While water cleavage on copper has been reported and investigated before, formation of molecular hydrogen at a single-crystal Cu[100] surface is here explored using density functional theory and transition state theory. It is found that although solvent catalysis seems possible, the fastest route to the formation of molecular hydrogen is the direct combination of hydrogen atoms on the copper surface. The activation free energy (ΔG(s)(‡)(f)) of hydrogen formation in condensed phase is 0.70 eV, which corresponds to a rate constant of 10 s(-1) at 298.15 K, i.e., a relatively rapid process. It is estimated that at least 2.4 ng hydrogen gas could form per cm(2) on a perfect copper surface.

  3. Gas hydrate formation rates from dissolved-phase methane in porous laboratory specimens

    USGS Publications Warehouse

    Waite, William F.; Spangenberg, E.K.

    2013-01-01

    Marine sands highly saturated with gas hydrates are potential energy resources, likely forming from methane dissolved in pore water. Laboratory fabrication of gas hydrate-bearing sands formed from dissolved-phase methane usually requires 1–2 months to attain the high hydrate saturations characteristic of naturally occurring energy resource targets. A series of gas hydrate formation tests, in which methane-supersaturated water circulates through 100, 240, and 200,000 cm3 vessels containing glass beads or unconsolidated sand, show that the rate-limiting step is dissolving gaseous-phase methane into the circulating water to form methane-supersaturated fluid. This implies that laboratory and natural hydrate formation rates are primarily limited by methane availability. Developing effective techniques for dissolving gaseous methane into water will increase formation rates above our observed (1 ± 0.5) × 10−7 mol of methane consumed for hydrate formation per minute per cubic centimeter of pore space, which corresponds to a hydrate saturation increase of 2 ± 1% per day, regardless of specimen size.

  4. Systematic Search for Chemical Reactions in Gas Phase Contributing to Methanol Formation in Interstellar Space.

    PubMed

    Gamez-Garcia, Victoria G; Galano, Annia

    2017-10-05

    A massive search for chemical routes leading to methanol formation in gas phase has been conducted using computational chemistry, at the CBS-QB3 level of theory. The calculations were performed at five different temperatures (100, 80, 50, 20, and 10 K) and at three pressures (0.1, 0.01, and 0.001 atm) for each temperature. The search was focused on identifying reactions with the necessary features to be viable in the interstellar medium (ISM). A searching strategy was applied to that purpose, which allowed to reduce an initial set of 678 possible reactions to a subset of 11 chemical routes that are recommended, for the first time, as potential candidates for contributing to methanol formation in the gas phase of the ISM. They are all barrier-less, and thus they are expected to take place at collision rates. Hopefully, including these reactions in the currently available models, for the gas-phase methanol formation in the ISM, would help improving the predicted fractional abundance of this molecule in dark clouds. Further investigations, especially those dealing with grain chemistry and electronic excited states, would be crucial to get a complete picture of the methanol formation in the ISM.

  5. The extended law of star formation: the combined role of gas and stars

    NASA Astrophysics Data System (ADS)

    Dib, Sami; Hony, Sacha; Blanc, Guillermo

    2017-08-01

    We present a model for the origin of the extended law of star formation in which the surface density of star formation (ΣSFR) depends not only on the local surface density of the gas (Σg) but also on the stellar surface density (Σ*), the velocity dispersion of the stars and on the scaling laws of turbulence in the gas. We compare our model with the spiral, face-on galaxy NGC 628 and show that the dependence of the star formation rate on the entire set of physical quantities for both gas and stars can help explain both the observed general trends in the Σg - ΣSFR and Σ* - ΣSFR relations, but also, and equally important, the scatter in these relations at any value of Σg and Σ*. Our results point out to the crucial role played by existing stars along with the gaseous component in setting the conditions for large scale gravitational instabilities and star formation in galactic discs.

  6. Three stages of bubble formation on submerged orifice under constant gas flow rate

    NASA Astrophysics Data System (ADS)

    Yu, Xianxian; Wang, Yiwei; Huang, Chenguang; Du, Tezhuan

    2015-12-01

    Bubble formation is involved in many engineering applications. It is important to understand the dynamics of bubble formation. This work reports experimental and numerical results of bubble formation on submerged orifice under constant gas flow rate. Compressible large eddy simulation combined volume of fluid (VOF) was adopted in simulation and results was validated by experiment. Bubble formation is divided into three stages in this paper, expansion stage, elongation stage and pinch-off stage. In expansion stage, The bubble grows radially due to the incoming gas flux, but the bubble base remains attached to the orifice. But as gas injected, the spherical bubble will go into the elongation stage when the downward resultant force is lager than upward resultant force. And when bubble neck's length is bigger than √2Ro the bubble will go into pinch-off stage. Cylindrical Rayleigh-Plesset equation can be used to describe the pinch-off stage. Uncertain parameter r in it is given reference value in this paper.

  7. Structure and Morphology of RESOLVE Galaxies in Relation to Environment, Gas, and Star Formation

    NASA Astrophysics Data System (ADS)

    Kannappan, Sheila; Hood, Callie; Snyder, Elaine M.; Eckert, Kathleen D.; Stark, David; RESOLVE Team

    2017-01-01

    We examine the structure and morphology of galaxies in the RESOLVE (REsolved Spectroscopy Of a Local VolumE) survey, a census of >1500 galaxies with baryonic mass >~10^9 Msun spanning multiple environments across >50,000 cubic Mpc of the nearby cosmic web. We investigate the statistical distribution of basic structural parameters as well as tidal streams and compact cores identified by image decomposition. Our results offer clues to the drivers of diversity in star formation and gas properties, particularly the unexpected phenomenon of red, gas depleted dwarf galaxies that are not satellites. RESOLVE was supported by NSF award AST-0955368.

  8. Study of Hind Limb Tissue Gas Phase Formation in Response to Suspended Adynamia and Hypokinesia

    NASA Technical Reports Server (NTRS)

    Butler, Bruce D.

    1996-01-01

    The purpose of this study was to investigate the hypothesis that reduced joint/muscle activity (hypo kinesia) as well as reduced or null loading of limbs (adynamia) in gravity would result in reduced decompression-induced gas phase and symptoms of decompression sickness (DCS). Finding a correlation between the two phenomena would correspond to the proposed reduction in tissue gas phase formation in astronauts undergoing decompression during extravehicular activity (EVA) in microgravity. The observation may further explain the reported low incidence of DCS in space.

  9. Gas-phase formation of silicon carbides, oxides, and sulphides from atomic silicon ions

    NASA Technical Reports Server (NTRS)

    Bohme, Diethard K.; Wlodek, Stanislaw; Fox, Arnold

    1989-01-01

    A systematic experimental study of the kinetics and mechanisms of the chemical reactions in the gas phase between ground-state Si(+)2p and a variety of astrophysical molecules. The aim of this study is to identify the reactions which trigger the formation of chemical bonds between silicon and carbon, oxygen and sulphur, and the chemical pathways which lead to further molecular growth. Such knowledge is valuable in the identification of new extraterrestrial silicon-bearing molecules and for an assessment of the gas-phase transition from atomic silicon to silicon carbide and silicate grain particles in carbon-rich and oxygen-rich astrophysical environments.

  10. The SAMI Galaxy Survey: extraplanar gas, galactic winds and their association with star formation history

    NASA Astrophysics Data System (ADS)

    Ho, I.-Ting; Medling, Anne M.; Bland-Hawthorn, Joss; Groves, Brent; Kewley, Lisa J.; Kobayashi, Chiaki; Dopita, Michael A.; Leslie, Sarah K.; Sharp, Rob; Allen, James T.; Bourne, Nathan; Bryant, Julia J.; Cortese, Luca; Croom, Scott M.; Dunne, Loretta; Fogarty, L. M. R.; Goodwin, Michael; Green, Andy W.; Konstantopoulos, Iraklis S.; Lawrence, Jon S.; Lorente, Nuria P. F.; Owers, Matt S.; Richards, Samuel; Sweet, Sarah M.; Tescari, Edoardo; Valiante, Elisabetta

    2016-04-01

    We investigate a sample of 40 local, main-sequence, edge-on disc galaxies using integral field spectroscopy with the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey to understand the link between properties of the extraplanar gas and their host galaxies. The kinematics properties of the extraplanar gas, including velocity asymmetries and increased dispersion, are used to differentiate galaxies hosting large-scale galactic winds from those dominated by the extended diffuse ionized gas. We find rather that a spectrum of diffuse gas-dominated to wind-dominated galaxies exist. The wind-dominated galaxies span a wide range of star formation rates (SFRs; -1 ≲ log (SFR/M⊙ yr-1) ≲ 0.5) across the whole stellar mass range of the sample (8.5 ≲ log (M*/M⊙) ≲ 11). The wind galaxies also span a wide range in SFR surface densities (10- 3-10- 1.5 M⊙ yr- 1 kpc- 2) that is much lower than the canonical threshold of 0.1 M⊙ yr- 1 kpc- 2. The wind galaxies on average have higher SFR surface densities and higher HδA values than those without strong wind signatures. The enhanced HδA indicates that bursts of star formation in the recent past are necessary for driving large-scale galactic winds. We demonstrate with Sloan Digital Sky Survey data that galaxies with high SFR surface density have experienced bursts of star formation in the recent past. Our results imply that the galactic winds revealed in our study are indeed driven by bursts of star formation, and thus probing star formation in the time domain is crucial for finding and understanding galactic winds.

  11. Hydrate Formation in Gas-Rich Marine Sediments: A Grain-Scale Model

    NASA Astrophysics Data System (ADS)

    Holtzman, R.; Juanes, R.

    2009-12-01

    We present a grain-scale model of marine sediment, which couples solid- and multiphase fluid-mechanics together with hydrate kinetics. The model is applied to investigate the spatial distribution of the different methane phases - gas and hydrate - within the hydrate stability zone. Sediment samples are generated from three-dimensional packs of spherical grains, mapping the void space into a pore network by tessellation. Gas invasion into the water-saturated sample is simulated by invasion-percolation, coupled with a discrete element method that resolves the grain mechanics. The coupled model accounts for forces exerted by the fluids, including cohesion associated with gas-brine surface tension. Hydrate growth is represented by a hydrate film along the gas-brine interface, which increases sediment cohesion by cementing the grain contacts. Our model of hydrate growth includes the possible rupture of the hydrate layer, which leads to the creation of new gas-water interface. In previous work, we have shown that fine-grained sediments (FGS) exhibit greater tendency to fracture, whereas capillary invasion is the preferred mode of methane gas transport in coarse-grained sediments (CGS). The gas invasion pattern has profound consequences on the hydrate distribution: a larger area-to-volume ratio of the gas cluster leads to a larger drop in gas pressure inside the growing hydrate shell, causing it to rupture. Repeated cycles of imbibition and hydrate growth accompanied by trapping of gas allow us to determine the distribution of hydrate and gas within the sediment as a function of time. Our pore-scale model suggests that, even when film rupture takes place, the conversion of gas to hydrate is slow. This explains two common field observations: the coexistence of gas and hydrate within the hydrate stability zone in CGS, and the high methane fluxes through fracture conduits in FGS. These results demonstrate the importance of accounting for the strong coupling among multiphase

  12. Evaluation of shale gas potential based on organic matter characteristics and gas concentration in the Devonian Horn River Formation, Canada

    NASA Astrophysics Data System (ADS)

    Choi, Jiyoung; Hong, Sung Kyung; Lee, Hyun Suk

    2017-04-01

    In this study, we investigate organic matter characteristics from the analysis of Rock-Eval6 and biomarker, and estimate methane concentration from headspace method in the Devonian Horn River Formation, which is one of the largest shale reservoir in western Canada. The Horn River Formation consists of the Evie, Otterpark and Muskwa members in ascending stratigraphic order. Total Organic Carbon (TOC) ranges from 0.34 to 7.57 wt%, with an average of 2.78 wt%. The Evie, middle Otterpark and Muskwa members have an average TOC of more than 3%, whereas those of the lower and upper Otterpark Member are less than 2%. Based on Pristane/n-C17 (0.2 0.6) and Phytane/n-C18 (0.3 0.9) ratios, the organic matter in the Evie, middle Otterpark and Muskwa members mainly consists of type II kerogen which are formed in reducing marine environment. Thermal maturity were examined through the use of the distributions of Phenanthrene (P) and Methylphenantrenes (MP) based on m/z 178 and 192 mass chromatograms, respectively (Radke et al., 1982). The methylphenanthrene index (MPI-1) are calculated as follows : MPI-1 = 1.5 × (2MP+3MP)/(P+1MP+9MP), and Ro are calculated as follows : Ro = -0.6 × MPI-1 + 2.3. Estimated Ro ranges between 1.88 and 1.93%, which indicates the last stage of wet gas generation. The methane concentrations in headspace range from 15 to 914 ppmv, with an average of 73.5 ppmv. The methane concentrations in the Evie, middle Otterpark and Muskwa members (up to 914 ppmv) are higher than those of the lower and upper Otterpark Member (up to 75 ppmv). Considering the organic geochemical characteristics and gas concentrations, the shale gas potentials of the Evie, middle Otterpark and Muskwa members are higher than those of other members.

  13. In-situ Micro-structural Studies of Gas Hydrate Formation in Sedimentary Matrices

    NASA Astrophysics Data System (ADS)

    Kuhs, Werner F.; Chaouachi, Marwen; Falenty, Andrzej; Sell, Kathleen; Schwarz, Jens-Oliver; Wolf, Martin; Enzmann, Frieder; Kersten, Michael; Haberthür, David

    2015-04-01

    The formation process of gas hydrates in sedimentary matrices is of crucial importance for the physical and transport properties of the resulting aggregates. This process has never been observed in-situ with sub-micron resolution. Here, we report on synchrotron-based micro-tomographic studies by which the nucleation and growth processes of gas hydrate were observed in different sedimentary matrices (natural quartz, glass beds with different surface properties, with and without admixtures of kaolinite and montmorillonite) at varying water saturation. The nucleation sites can be easily identified and the growth pattern is clearly established. In under-saturated sediments the nucleation starts at the water-gas interface and proceeds from there to form predominantly isometric single crystals of 10-20μm size. Using a newly developed synchrotron-based method we have determined the crystallite size distributions (CSD) of the gas hydrate in the sedimentary matrix confirming in a quantitative and statistically relevant manner the impressions from the tomographic reconstructions. It is noteworthy that the CSDs from synthetic hydrates are distinctly smaller than those of natural gas hydrates [1], which suggest that coarsening processes take place in the sedimentary matrix after the initial hydrate formation. Understanding the processes of formation and coarsening may eventually permit the determination of the age of gas hydrates in sedimentary matrices [2], which are largely unknown at present. Furthermore, the full micro-structural picture and its evolution will enable quantitative digital rock physics modeling to reveal poroelastic properties and in this way to support the exploration and exploitation of gas hydrate resources in the future. [1] Klapp S.A., Hemes S., Klein H., Bohrmann G., McDonald I., Kuhs W.F. Grain size measurements of natural gas hydrates. Marine Geology 2010; 274(1-4):85-94. [2] Klapp S.A., Klein H, Kuhs W.F. First determination of gas hydrate

  14. Is Submarine Groundwater Discharge a Gas Hydrate Formation Mechanism on the Circum-Arctic Shelf?

    NASA Astrophysics Data System (ADS)

    Frederick, J. M.; Buffett, B. A.

    2015-12-01

    Methane hydrate is an ice-like solid that can sequester large quantities of methane gas in marine sediments along most continental margins where thermodynamic conditions permit its formation. Along the circum-Arctic shelf, relict permafrost-associated methane hydrate deposits formed when non-glaciated portions of the shelf experienced subaerial exposure during ocean transgressions. Gas hydrate stability and the permeability of circum-Arctic shelf sediments to gas migration is closely linked with relict submarine permafrost. Heat flow observations on the Alaskan North Slope and Canadian Beaufort Shelf suggest the movement of groundwater offshore, but direct observations of groundwater flow do not exist. Submarine discharge, an offshore flow of fresh, terrestrial groundwater, can affect the temperature and salinity field in shelf sediments, and may be an important factor in submarine permafrost and gas hydrate evolution on the Arctic continental shelf. Submarine groundwater discharge may also enhance the transport of organic matter for methanogenesis within marine sediments. Because it is buoyancy-driven, the velocity field contains regions with a vertical (upward) component as groundwater flows offshore. This combination of factors makes submarine groundwater discharge a potential mechanism controlling permafrost-associated gas hydrate evolution on the Arctic continental shelf. In this study, we quantitatively investigate the feasibility of submarine groundwater discharge as a control on permafrost-associated gas hydrate formation on the Arctic continental shelf, using the Canadian Beaufort Shelf as an example. We have developed a shelf-scale, two-dimensional numerical model based on the finite volume method for two-phase flow of pore fluid and methane gas within Arctic shelf sediments. The model tracks the evolution of the pressure, temperature, salinity, methane gas, methane hydrate, and permafrost fields given imposed boundary conditions, with latent heat of

  15. Case of a cerebral abscess caused by Porphyromonas gingivalis in a subject with periodontitis

    PubMed Central

    Grisar, Koenraad; Maes, Honorine; Politis, Constantinus

    2017-01-01

    We report the case of a 65-year-old man presenting with generalised seizures after developing a right frontal brain abscess. Stereotactic aspiration and subsequent matrix assisted laser desorption/ionisation time-of-flight analyzer (MALDI-TOF) spectrometry revealed Porphyromonas gingivalis as the only causative anaerobe microorganism. Secondary incision and drainage was required due to neurological deterioration with increased dimensions of the abscess, intracranial pressure and formation of a subdural occipitoparietal empyema. Oral imaging was positive for apical periodontitis of multiple elements; therefore, the remaining dentition was removed. Targeted antibiotic treatment included intravenous ceftriaxone and ornidazole. The patient was discharged to our revalidation unit 59 days after admission to make a full recovery. To the best of our knowledge, this is the sixth reported case of P. gingivalis causing an intracranial abscess and the third case of a true intracerebral parenchymal abscess caused by this bacterium. PMID:28228396

  16. Recurrent obturator abscess with spontaneous expulsion of the mesh after transobturator tape operation.

    PubMed

    Ugurlucan, Funda Gungor; Ozsurmeli, Mehmet; Bakir, Baris; Saygili, Halil; Yalcin, Onay

    2013-12-01

    The transobturator tape operation has been the most popular method of SUI surgery worldwide owing to its low complication rate and high success rate. However, erosions and abscesses secondary to transobturator tape have been observed. Here we report a 36-year-old woman referred to our unit with fever, persistent swelling in the left groin, difficulty in walking, and a tape that came through the vagina, 4 years after the transobturator tape operation. She had a history of ischiorectal abscess and rectovaginal fistula. A recurrent obturator abscess with fistula formation and spontaneous expulsion of the mesh was diagnosed. The patient underwent antibiotic therapy, incision through the fistula tract, drainage of the abscess, and removal of the necrotic material. Patients should be informed about risks of erosion and infection and that pain and foul smelling vaginal discharge might be the first signs of severe infectious morbidities after transobturator tape operation.

  17. Multiple Pyogenic Liver Abscesses Caused by Microperforation of an Idiopathic Cecal Ulcer.

    PubMed

    Yeom, Dong Han; Sohn, Ki Chang; Chu, Min Su; Jo, Dong Ho; Cho, Eun Young; Kim, Haak Cheoul

    2016-01-25

    Idiopathic cecal ulcer is a rare disease entity of unknown cause diagnosed by ruling out other known causes of cecal ulceration. The most common complication of an idiopathic cecal ulcer is bleeding; perforation, peritonitis, abscess, and stricture formation have been noted. The authors treated a 53-year-old woman who presented with fever and intermittent right upper quadrant abdominal pain. Multiple pyogenic liver abscess and a solitary cecal ulcer were diagnosed by radiologic, endoscopic, and pathologic examination, followed by laparoscopic cecectomy. After extensive study, we concluded that this patient's liver abscesses were a complication of the idiopathic cecal ulcer. Herein, we report a case of multiple pyogenic liver abscess caused by microperforation of idiopathic cecal ulcer.

  18. Reversal of tetraplegia in a patient with haematogenous cervical epidural abscess.

    PubMed

    Katonis, Pavlos; Souvatzis, Xenia; Tsavalas, Nikolaos; Alpantaki, Kalliopi

    2011-08-01

    Pyogenic haematogenous cervical epidural abscess complicated by tetraplegia is an uncommon entity, but its clinical importance overshadows its rarity. Predisposing risk factors for spinal epidural abscess include diabetes, intravenous drug abuse, liver disease, renal failure, malignancy, HIV, infection elsewhere, rheumatoid conditions, trauma and a number of spinal interventions. Lack of recovery and death are much more frequent when complete paralysis exists since more than 24 to 48 hours. Most authors combine decompressive laminectomy and antibiotics. Anterior decompression and needle aspiration are rarely used, the former more specifically in case of anterior abscess formation. A high index of suspicion along with reliance on gadolinium-enhanced MRI is essential to diagnose the pathology and institute appropriate treatment on an individual basis. The authors report on a diabetic male patient who developed a cervical epidural abscess with tetraplegia after dental extraction. He was treated within six hours by one stage anterior/posterior decompression and fusion, with complete recovery.

  19. Laparoscopic Treatment of a Pyogenic Hepatic Abscess Caused by Transmural Duodenal Perforation of a Toothpick.

    PubMed

    Turaihi, Hassan; Assam, Jed; Zanfes, Justin; Thambi-Pillai, Thavam

    2017-08-01

    The development of pyogenic hepatic abscess resulting from perforation of the gastrointestinal tract is a rare pathologic finding. It is a condition that can be fatal making early detection and subsequent removal of the inciting foreign body critical to avoid more deleterious sequela. Yet, its initial presentation tends to be nonspecific and typically is only discovered once surgical investigation into the cause of persisting abscess formation is performed. In this study, laparoscopic treatment of a 52-year-old male with a non-resolving hepatic abscess due to transmural gastrointestinal perforation of a toothpick is presented. Although a rare finding, reports of foreign body induced hepatic abscess have recently increased in the world literature, allowing some preliminary efforts in proposing diagnostic characterization. Yet, more case studies will be required to permit validation of these findings making continued reporting of this pathologic process critical. Copyright© South Dakota State Medical Association.

  20. Case of a cerebral abscess caused by Porphyromonas gingivalis in a subject with periodontitis.

    PubMed

    Van der Cruyssen, Frederic; Grisar, Koenraad; Maes, Honorine; Politis, Constantinus

    2017-02-22

    We report the case of a 65-year-old man presenting with generalised seizures after developing a right frontal brain abscess. Stereotactic aspiration and subsequent matrix assisted laser desorption/ionisation time-of-flight analyzer (MALDI-TOF) spectrometry revealed Porphyromonas gingivalis as the only causative anaerobe microorganism. Secondary incision and drainage was required due to neurological deterioration with increased dimensions of the abscess, intracranial pressure and formation of a subdural occipitoparietal empyema. Oral imaging was positive for apical periodontitis of multiple elements; therefore, the remaining dentition was removed. Targeted antibiotic treatment included intravenous ceftriaxone and ornidazole. The patient was discharged to our revalidation unit 59 days after admission to make a full recovery. To the best of our knowledge, this is the sixth reported case of P. gingivalis causing an intracranial abscess and the third case of a true intracerebral parenchymal abscess caused by this bacterium. 2017 BMJ Publishing Group Ltd.

  1. Pituitary abscess after autologous bone marrow transplantation.

    PubMed

    Leff, R S; Martino, R L; Pollock, W J; Knight, W A

    1989-05-01

    The first case of pituitary abscess arising in a patient during recovery from autologous bone marrow transplantation is reported. A 31-year-old man with a 9 month history of T-cell lymphoma died suddenly more than 60 days after successful treatment with high-dose cyclophosphamide, total body irradiation, and autologous bone marrow infusion. Autopsy revealed a pituitary abscess associated with clinically silent sphenoid sinusitis. Unique aspects of this case are presented and clinical and pathologic features of pituitary abscess are reviewed. Although rare, pituitary abscess may complicate recovery from bone marrow transplantation.

  2. Pyogenic brain abscess, a 15 year survey.

    PubMed

    Helweg-Larsen, Jannik; Astradsson, Arnar; Richhall, Humeira; Erdal, Jesper; Laursen, Alex; Brennum, Jannick

    2012-11-30

    Brain abscess is a potentially fatal disease. This study assesses clinical aspects of brain abscess in a large hospital cohort. Retrospective review of adult patients with pyogenic brain abscess at Rigshospitalet University Hospital, Denmark between 1994 and 2009. Prognostic factors associated with Glasgow Outcome Score (GOS) (death, severe disability or vegetative state) were assessed by logistic regression. 102 patients were included. On admission, only 20% of patients had a triad of fever, headache and nausea, 39% had no fever, 26% had normal CRP and 49% had no leucocytosis. Median delay from symptom onset to antibiotic treatment was 7 days (range 0-97 days). Source of infection was contiguous in 36%, haematogenous in 28%, surgical or traumatic in 9% and unknown in 27% of cases. Abscess location did not accurately predict the portal of entry. 67% were treated by burr hole aspiration, 20% by craniotomy and 13% by antibiotics alone. Median duration of antibiotic treatment was 62 days. No cases of recurrent abscess were observed. At discharge 23% had GOS ≤3. The 1-, 3- and 12-month mortality was 11%, 17% and 19%. Adverse outcome was associated with a low GCS at admission, presence of comorbidities and intraventricular rupture of abscess. The clinical signs of brain abscess are unspecific, many patients presented without clear signs of infection and diagnosis and treatment were often delayed. Decreased GCS, presence of comorbidities and intraventricular rupture of brain abscess were associated with poor outcome. Brain abscess remains associated with considerable morbidity and mortality.

  3. Vesicoovarian Fistula on an Endometriosis Abscessed Cyst

    PubMed Central

    Tran, C.; Even, M.; Carbonnel, M.; Preaux, F.; Isnard, F.; Rault, A.; Rouanne, M.; Ayoubi, J. M.

    2014-01-01

    We report the case of a patient who developed a vesicoovarian fistula on an endometriosis abscessed cyst. The patient presented with an advanced endometriosis stage IV complicated with a right ovarian abscessed cyst of 10 cm. A first coelioscopy with cystectomy was realized. After surgery, a voiding cystography highlighted a fistula between the ovarian abscess and the bladder. A second surgery by median laparotomy was realized with the resection of the right ovarian abscess and the resection of vesical fistula. PMID:25152819

  4. Laparoscopic Drainage of Pyogenic Liver Abscess

    PubMed Central

    Aydin, Cemalettin; Piskin, Turgut; Sumer, Fatih; Barut, Bora

    2010-01-01

    Background and Objectives: Pyogenic liver abscesses are mainly treated by percutaneous aspiration or drainage under antibiotic cover. If interventional radiology fails, surgical drainage becomes necessary. Recently, we performed laparoscopic liver abscess drainage successfully, and we aimed to focus on the topic in light of a systematic review of the literature. Methods: A 22-year-old man was admitted with a 4.5-cm multiloculated abscess in the left lobe of the liver. The abscess did not resolve with antibiotic-alone therapy. Percutaneous aspiration was unsuccessful due to viscous and multiloculated contents. Percutaneous catheter placement was not amenable. Laparoscopic abscess drainage was preferred over open abscess drainage. We used 3 trocars, operation time was 40 minutes, and blood loss was minimal. In the mean time, we searched PubMed using the key words [(liver OR hepatic) abscess*] AND [laparoscop* OR (minimal* AND invasiv*)]. Results: Postoperative recovery of the patient was uneventful, and the patient was asymptomatic after 3 months of follow-up. In the literature search, we found 53 liver abscesses (51 pyogenic and 2 amebic) that were treated by laparoscopy. Mean success rate was 90.5% (range, 85% to 100%) and conversion rate was zero. Conclusion: Treatment of liver abscess is mainly percutaneous drainage. Laparoscopic drainage should be selected as an alternative before open drainage when other modalities have failed. PMID:21333200

  5. Pyogenic brain abscess, a 15 year survey

    PubMed Central

    2012-01-01

    Background Brain abscess is a potentially fatal disease. This study assesses clinical aspects of brain abscess in a large hospital cohort. Methods Retrospective review of adult patients with pyogenic brain abscess at Rigshospitalet University Hospital, Denmark between 1994 and 2009. Prognostic factors associated with Glasgow Outcome Score (GOS) (death, severe disability or vegetative state) were assessed by logistic regression. Results 102 patients were included. On admission, only 20% of patients had a triad of fever, headache and nausea, 39% had no fever, 26% had normal CRP and 49% had no leucocytosis. Median delay from symptom onset to antibiotic treatment was 7 days (range 0–97 days). Source of infection was contiguous in 36%, haematogenous in 28%, surgical or traumatic in 9% and unknown in 27% of cases. Abscess location did not accurately predict the portal of entry. 67% were treated by burr hole aspiration, 20% by craniotomy and 13% by antibiotics alone. Median duration of antibiotic treatment was 62 days. No cases of recurrent abscess were observed. At discharge 23% had GOS ≤3. The 1-, 3- and 12-month mortality was 11%, 17% and 19%. Adverse outcome was associated with a low GCS at admission, presence of comorbidities and intraventricular rupture of abscess. Conclusions The clinical signs of brain abscess are unspecific, many patients presented without clear signs of infection and diagnosis and treatment were often delayed. Decreased GCS, presence of comorbidities and intraventricular rupture of brain abscess were associated with poor outcome. Brain abscess remains associated with considerable morbidity and mortality. PMID:23193986

  6. Evolution in management of otogenic brain abscess.

    PubMed

    Szyfter, Witold; Kruk-Zagajewska, Aleksandra; Borucki, Lukasz; Bartochowska, Anna

    2012-04-01

    To present the therapeutic results related with treating 103 patients with cerebral abscesses of otogenic origin during 3 various time frames (1953-1977, 1978-1989, and 1990-2011). A total of 103 patients with cerebral abscess of otogenic origin. Diagnostics and treatment. Analysis of mortality rates, abscess location and its basis, coexisting complications, neurological condition at admittance, bacteriological tests, and presentation of the results of abscess treatment with the use of neuronavigation. Mortality rates dropped systematically from the initial value of 35% observed between 1953 and 1977, to 14% between 1978 and 1989, and finally reached 3% between 1990 and 2011. Abscesses were mainly located within the temporal lobe. They predominantly resulted from chronic inflammation of the middle ear. A wide panel of complications was associated with them. Strong concurrence between results of cultures taken from the ear and the abscess was noted. Cerebral abscesses remain one of the most severe complications related with inflammation of the middle ear. Both the operative methods and the postoperative care evolved (introduction of surgical microscope, new generation of antibiotics), the preoperative diagnostics facilitating the diagnosis and localization of the abscess progressed; nonetheless, the principles underlying the operative treatment remained unchanged. Neuronavigation constitutes a very important and supportive element in the management of otogenic brain abscesses.

  7. Kinetic study of model reactions in the gas phase at the early stage of coke formation

    SciTech Connect

    Nohara, D.; Sakai, T. )

    1992-01-01

    This paper reports that the most probable gas-phase reactions at the early stage of coke formation were elucidated by kinetic study on the model reactions adopted for formation of cyclic compounds and growth of ring. It was revealed that the formation and growth of ring proceeded mainly through cycloaddition of butadiene or allyl radicals to unsaturated hydrocarbons at relatively low temperatures ({approximately}600{degrees}C), i.e., through a Diels-Alder type reaction. On the other hand, such growth of ring as formation of biphenyl accompanying dehydrogenation from benzene can proceed only at the higher temperatures. It was also revealed that in the growth of the ring, cycloaddition of butadiene favors a cyclic olefin molecule that possesses a nonconjugated double bond and a nearly planar structure.

  8. Anaerobic and aerobic hydrogen gas formation by the blue-green alga Anabaena cylindrica.

    PubMed

    Daday, A; Platz, R A; Smith, G D

    1977-11-01

    An investigation was made of certain factors involved in the formation of hydrogen gas, both in an anaerobic environment (argon) and in air, by the blue-green alga Anabaena cylindrica. The alga had not been previously adapted under hydrogen gas and hence the hydrogen evolution occurred entirely within the nitrogen-fixing heterocyst cells; organisms grown in a fixed nitrogen source, and which were therefore devoid of heterocysts, did not produce hydrogen under these conditions. Use of the inhibitor dichlorophenyl-dimethyl urea showed that hydrogen formation was directly dependent on photosystem I and only indirectly dependent on photosystem II, consistent with heterocysts being the site of hydrogen formation. The uncouplers carbonyl cyanide chlorophenyl hydrazone and dinitrophenol almost completely inhibited hydrogen formation, indicating that the process occurs almost entirely via the adenosine 5'-triphosphate-dependent nitrogenase. Salicylaldoxime also inhibited hydrogen formation, again illustrating the necessity of photophosphorylation. Whereas hydrogen formation could usually only be observed in anaerobic, dinitrogen-free environments, incubation in the presence of the dinitrogen-fixing inhibitor carbon monoxide plus the hydrogenase inhibitor acetylene resulted in significant formation of hydrogen even in air. Hydrogen formation was studied in batch cultures as a function of age of the cultures and also as a function of culture concentration, in both cases the cultures being harvested in logarithmic growth. Hydrogen evolution (and acetylene-reducing activity) exhibited a distinct maximum with respect to the age of the cultures. Finally, the levels of the protective enzyme, superoxide dismutase, were measured in heterocyst and vegetative cell fractions of the organism; the level was twice as high in heterocyst cells (2.3 units/mg of protein) as in vegetative cells (1.1 units/mg of protein). A simple procedure for isolating heterocyst cells is described.

  9. Formation of new stellar populations from gas accreted by massive young star clusters.

    PubMed

    Li, Chengyuan; de Grijs, Richard; Deng, Licai; Geller, Aaron M; Xin, Yu; Hu, Yi; Faucher-Giguère, Claude-André

    2016-01-28

    Stars in clusters are thought to form in a single burst from a common progenitor cloud of molecular gas. However, massive, old 'globular' clusters--those with ages greater than ten billion years and masses several hundred thousand times that of the Sun--often harbour multiple stellar populations, indicating that more than one star-forming event occurred during their lifetimes. Colliding stellar winds from late-stage, asymptotic-giant-branch stars are often suggested to be triggers of second-generation star formation. For this to occur, the initial cluster masses need to be greater than a few million solar masses. Here we report observations of three massive relatively young star clusters (1-2 billion years old) in the Magellanic Clouds that show clear evidence of burst-like star formation that occurred a few hundred million years after their initial formation era. We show that such clusters could have accreted sufficient gas to form new stars if they had orbited in their host galaxies' gaseous disks throughout the period between their initial formation and the more recent bursts of star formation. This process may eventually give rise to the ubiquitous multiple stellar populations in globular clusters.

  10. Secondary Organic Aerosol formation from the gas-phase ozonolysis of 3-methylcatechol and 4-methylcatechol

    NASA Astrophysics Data System (ADS)

    Coeur-Tourneur, Cécile; Foulon, Valentine; Laréal, Michel; Cassez, Andy; Zhao, Weixiong

    2010-05-01

    Secondary Organic Aerosol (SOA) formation during the ozonolysis of 3-methylcatechol (3-methyl-1,2-dihydroxybenzene) and 4-methylcatechol (3-methyl-1,2-dihydroxybenzene) was investigated using a simulation chamber (8 m3) at atmospheric pressure, room temperature (294 ± 2 K) and low relative humidity (5-10%). The initial mixing ratios were as follows (in ppb): 3-methylcatechol (194-1059), 4-methylcatechol (204-1188) and ozone (93-531). The ozone and methylcatechol concentrations were followed by UV photometry and GC-FID (Gas Chromatography - Flame ionization detector), respectively and the aerosol production was monitored using a SMPS (Scanning Mobility Particle Sizer). The SOA yields (Y) were determined as the ratio of the suspended aerosol mass corrected for wall losses (Mo) to the total reacted methylcatechol concentrations assuming a particle density of 1.4 g cm-3. The aerosol formation yield increases as the initial methylcatechol concentration increases, and leads to aerosol yields ranging from 32% to 67% and from 30% to 64% for 3-methylcatechol and 4-methylcatechol, respectively. Y is a strong function of Mo and the organic aerosol formation can be expressed by a one-product gas/particle partitioning absorption model. These data are comparable to those published in a recent study on secondary organic aerosol formation from catechol ozonolysis. To our knowledge, this work represents the first investigation of SOA formation from the ozone reaction with methylcatechols.

  11. Carbon nanomaterial Formation on Fresh-Reduced Iron by Converted Natural Gas

    NASA Astrophysics Data System (ADS)

    Nebesnyi, A.; Kotov, V.; Sviatenko, A.; Filonenko, D.; Khovavko, A.; Bondarenko, B.

    2017-02-01

    The mechanism of carbon nanomaterial formation at moderate temperatures while processing fresh-reduced iron by products of air conversion of natural gas is considered. It is shown that under given conditions, the size and the shape of the resulting carbon are dependent on the temperature and the size of microscopic iron grains formed during reduction. These iron grains are the catalyzer of the reaction of carbon monoxide disproportionation. It is concluded that the formation of a nucleus of the new carbon phase occurs at the contact boundaries of neighboring grains of newly reduced iron with the subsequent formation in these places of ring-shaped carbon cuffs. Nanotubes are forming as a result of further carbon crystallization, and separation of iron particles from the main mass is occurring, i.e., there is a fragmentation of the substance of the catalyst. According to the results of laboratory studies, the optimum temperature of carbon nanotube formation in the environment of converted gas is 600-650 °C. The evidence of the hypothesis that the mechanism of the reaction of carbon monoxide disproportionation flows through the intermediate stage of iron oxides formation is given.

  12. The formation of chondrules at high gas pressures in the solar nebula.

    PubMed

    Galy, A; Young, E D; Ash, R D; O'Nions, R K

    2000-12-01

    High-precision magnesium isotope measurements of whole chondrules from the Allende carbonaceous chondrite meteorite show that some aluminum-rich Allende chondrules formed at or near the time of formation of calcium-aluminum-rich inclusions and that some others formed later and incorporated precursors previously enriched in magnesium-26. Chondrule magnesium-25/magnesium-24 correlates with [magnesium]/[aluminum] and size, the aluminum-rich, smaller chondrules being the most enriched in the heavy isotopes of magnesium. These relations imply that high gas pressures prevailed during chondrule formation in the solar nebula.

  13. Numerical Model of Hydrate Formation and Dissociation With Free Gas Flow for a Global Inventory

    NASA Astrophysics Data System (ADS)

    Scandella, B.; Juanes, R.

    2009-12-01

    Methane hydrates hold great potential as an energy resource but also pose the threat, if they dissociate, of contributing to the greenhouse effect. In order to evaluate the risks and opportunities they present, we have developed a numerical model of hydrate formation and dissociation. This one-dimensional, continuum model is simple enough to be applied globally to estimate the total inventory of hydrate and trapped gas, yet captures multiphase flow effects not accounted for in previous inventory estimates. Preliminary results compare behavior regimes in typical active and passive continental margins, including fracture-dominated gas invasion, slow capillary invasion, and dynamic steady states. These results identify the key parameters that need to be estimated at a global scale in order to model the formation of current hydrate accumulations and their response to production and climate change.

  14. Selective covalent bond formation in polypeptide ions via gas-phase ion/ion reaction chemistry.

    PubMed

    Han, Hongling; McLuckey, Scott A

    2009-09-16

    Primary amines present in protonated polypeptides can be covalently modified via gas-phase ion/ion reactions using bifunctional reagent ions. The use of reagent anions with a charge-bearing site that leads to strong interactions with the polypeptide, such as sulfonic acid, gives rise to the formation of a long-lived adduct. A distinct reactive functional group, an aldehyde in the present case, can then undergo reaction with the peptide. Collisional activation of the adduct ion formed from a reagent with an aldehyde group and a peptide ion with a primary amine gives rise to water loss in conjunction with imine (Schiff base) formation. The covalently bound modification is retained upon subsequent collisional activation. This work demonstrates the ability to selectively modify polypeptide ions in the gas phase within the context of a multistage mass spectrometry experiment.

  15. Dense Gas Fraction and Star-formation Efficiency Variations in the Antennae Galaxies

    NASA Astrophysics Data System (ADS)

    Bigiel, F.; Leroy, A. K.; Blitz, L.; Bolatto, A. D.; da Cunha, E.; Rosolowsky, E.; Sandstrom, K.; Usero, A.

    2015-12-01

    We use the Combined Array for Research in Millimeter-wave Astronomy (CARMA) millimeter interferometer to map the Antennae Galaxies (NGC 4038/39), tracing the bulk of the molecular gas via the 12CO(1-0) line and denser molecular gas via the high density transitions HCN(1-0), HCO+(1-0), CS(2-1), and HNC(1-0). We detect bright emission from all tracers in both the two nuclei and three locales in the overlap region between the two nuclei. These three overlap region peaks correspond to previously identified “supergiant molecular clouds.” We combine the CARMA data with Herschel infrared (IR) data to compare observational indicators of the star formation efficiency (star formation rate/H2 ∝ IR/CO), dense gas fraction (HCN/CO), and dense gas star formation efficiency (IR/HCN). Regions within the Antennae show ratios consistent with those seen for entire galaxies, but these ratios vary by up to a factor of six within the galaxy. The five detected regions vary strongly in both their integrated intensities and these ratios. The northern nucleus is the brightest region in millimeter-wave line emission, while the overlap region is the brightest part of the system in the IR. We combine the CARMA and Herschel data with ALMA CO data to report line ratio patterns for each bright point. CO shows a declining spectral line energy distribution, consistent with previous studies. HCO+ (1-0) emission is stronger than HCN (1-0) emission, perhaps indicating either more gas at moderate densities or higher optical depth than is commonly seen in more advanced mergers.

  16. DENSE GAS FRACTION AND STAR FORMATION EFFICIENCY VARIATIONS IN THE ANTENNAE GALAXIES

    SciTech Connect

    Bigiel, F.; Leroy, A. K.; Blitz, L.; Bolatto, A. D.; Da Cunha, E.; Rosolowsky, E.; Sandstrom, K.; Usero, A.

    2015-12-20

    We use the Combined Array for Research in Millimeter-wave Astronomy (CARMA) millimeter interferometer to map the Antennae Galaxies (NGC 4038/39), tracing the bulk of the molecular gas via the {sup 12}CO(1–0) line and denser molecular gas via the high density transitions HCN(1–0), HCO{sup +}(1–0), CS(2–1), and HNC(1–0). We detect bright emission from all tracers in both the two nuclei and three locales in the overlap region between the two nuclei. These three overlap region peaks correspond to previously identified “supergiant molecular clouds.” We combine the CARMA data with Herschel infrared (IR) data to compare observational indicators of the star formation efficiency (star formation rate/H{sub 2} ∝ IR/CO), dense gas fraction (HCN/CO), and dense gas star formation efficiency (IR/HCN). Regions within the Antennae show ratios consistent with those seen for entire galaxies, but these ratios vary by up to a factor of six within the galaxy. The five detected regions vary strongly in both their integrated intensities and these ratios. The northern nucleus is the brightest region in millimeter-wave line emission, while the overlap region is the brightest part of the system in the IR. We combine the CARMA and Herschel data with ALMA CO data to report line ratio patterns for each bright point. CO shows a declining spectral line energy distribution, consistent with previous studies. HCO{sup +} (1–0) emission is stronger than HCN (1–0) emission, perhaps indicating either more gas at moderate densities or higher optical depth than is commonly seen in more advanced mergers.

  17. Rapid Formation of Supermassive Black Hole Binaries in Galaxy Mergers with Gas

    SciTech Connect

    Mayer, L.; Kazantzidis, S.; Madau, P.; Colpi, M.; Quinn, T.; Wadsley, J.; /McMaster U.

    2008-03-24

    Supermassive black holes (SMBHs) are a ubiquitous component of the nuclei of galaxies. It is normally assumed that, following the merger of two massive galaxies, a SMBH binary will form, shrink due to stellar or gas dynamical processes and ultimately coalesce by emitting a burst of gravitational waves. However, so far it has not been possible to show how two SMBHs bind during a galaxy merger with gas due to the difficulty of modeling a wide range of spatial scales. Here we report hydrodynamical simulations that track the formation of a SMBH binary down to scales of a few light years following the collision between two spiral galaxies. A massive, turbulent nuclear gaseous disk arises as a result of the galaxy merger. The black holes form an eccentric binary in the disk in less than a million years as a result of the gravitational drag from the gas rather than from the stars.

  18. Hydrophobic amino acids as a new class of kinetic inhibitors for gas hydrate formation

    PubMed Central

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Lee, Bo Ram; Park, Da-Hye; Han, Kunwoo; Lee, Kun-Hong

    2013-01-01

    As the foundation of energy industry moves towards gas, flow assurance technology preventing pipelines from hydrate blockages becomes increasingly significant. However, the principle of hydrate inhibition is still poorly understood. Here, we examined natural hydrophobic amino acids as novel kinetic hydrate inhibitors (KHIs), and investigated hydrate inhibition phenomena by using them as a model system. Amino acids with lower hydrophobicity were found to be better KHIs to delay nucleation and retard growth, working by disrupting the water hydrogen bond network, while those with higher hydrophobicity strengthened the local water structure. It was found that perturbation of the water structure around KHIs plays a critical role in hydrate inhibition. This suggestion of a new class of KHIs will aid development of KHIs with enhanced biodegradability, and the present findings will accelerate the improved control of hydrate formation for natural gas exploitation and the utilization of hydrates as next-generation gas capture media. PMID:23938301

  19. Rapid formation of supermassive black hole binaries in galaxy mergers with gas.

    PubMed

    Mayer, L; Kazantzidis, S; Madau, P; Colpi, M; Quinn, T; Wadsley, J

    2007-06-29

    Supermassive black holes (SMBHs) are a ubiquitous component of the nuclei of galaxies. It is normally assumed that after the merger of two massive galaxies, a SMBH binary will form, shrink because of stellar or gas dynamical processes, and ultimately coalesce by emitting a burst of gravitational waves. However, so far it has not been possible to show how two SMBHs bind during a galaxy merger with gas because of the difficulty of modeling a wide range of spatial scales. Here we report hydrodynamical simulations that track the formation of a SMBH binary down to scales of a few light years after the collision between two spiral galaxies. A massive, turbulent, nuclear gaseous disk arises as a result of the galaxy merger. The black holes form an eccentric binary in the disk in less than 1 million years as a result of the gravitational drag from the gas rather than from the stars.

  20. Sub-shock formation in Grad 10-moment equations for a binary gas mixture

    NASA Astrophysics Data System (ADS)

    Bisi, Marzia; Conforto, Fiammetta; Martalò, Giorgio

    2016-09-01

    The shock structure problem for Grad 10-moment equations for an inert binary mixture is investigated: necessary conditions for the formation of sub-shocks in fields of only one gas or of both components are rigorously obtained, and a detailed comparison with the shock-wave structure of its principal sub-system (deduced assuming vanishing viscous stress tensors) and of the equilibrium Euler sub-system is performed. Some numerical simulations for a mixture of argon and helium are presented.

  1. Microbial consortia controlling biogenic gas formation in the Qaidam Basin of western China

    NASA Astrophysics Data System (ADS)

    Shuai, Yanhua; Zhang, Shuichang; Grasby, Stephen E.; Hou, Weiguo; Chen, Zhuoheng; Huang, Ling; Kui, Mingqing; Xu, Yirui; Wang, Yang

    2016-08-01

    Knowledge of what controls the activity of subsurface microbial communities is critical for assessing and managing biogenic methane resources. In this study, 19 formation waters and five gas samples were collected at depths of 800 to 1900 m from Quaternary biogenic gas fields of the Qaidam Basin, China. The formation waters were brines with chloride (Cl) concentrations from 1200 to 2700 mM. Bacterial 16S rRNA gene copies ranged from 3.75 × 104 to 2.23 × 106 copies mL-1 of water, and those of archaea ranged from 2.44 × 103 to 4.66 × 107 copies mL-1 of water. Both bacterial and archaea 16 s rRNA gene copies were negatively correlated with Cl concentration. The microbial community structure differed significantly depending on Cl concentrations. At high Cl waters (>1800 mM), the microbial community showed a halophilic signature made up of several abundant taxonomic groups within Firmicules, γ-Proteobacteria, and methylotrophic Methanosarcinales. At low Cl, Firmicules and hydrogenotrophic methanogens were dominant members. The proportion of inferred hydrogenotrophic methanogens decreased from 89% to 14% of total archaeal reads with increasing Cl concentration; in contrast, methylotrophic species increased from 11% to 85%. Given that the proportion of hydrogenotrophic species was positively correlated with the archaeal gene abundances, we suggest that Cl concentrations primarily constrain the activity of archaea catalyzing H2 reduction of CO2. Our results show that dilution of formation waters is critical in the process of biogenic gas formation, suggesting that an engineered decrease in Cl concentrations may induce methanogenesis as a potential method to increase gas reserves in such areas in the future.

  2. Progressive gas formation in a deceased person during mortuary storage demonstrated on computed tomography.

    PubMed

    Singh, Mansharan Kaur Chainchel; O'Donnell, Christopher; Woodford, Noel William

    2009-01-01

    We report the case of an 82-year-old woman with a past history of diabetes mellitus who died following blunt head injury sustained in a fall resulting in an acute subdural hematoma. Serial postmortem CT scans of the chest and abdomen performed over a 3-day period demonstrated progressive intra-hepatic and intra-cardiac gas formation whilst the deceased was stored in a standard mortuary refrigerator at a nominated temperature of 4 degrees C. Measured mortuary refrigerator temperatures over a 7 day period showed statistically significant day to day variability in temperatures above 4 degrees C as well as variations in temperature depending on location within the refrigerator space. In the absence of other known factors associated with such gas formation, putrefaction seems the likely cause despite a lack of obvious external features. This phenomenon must therefore be taken into account when interpreting the presence of visceral gas on postmortem CT and relating such gas to the cause of death.

  3. Model of two-dimensional electron gas formation at ferroelectric interfaces

    SciTech Connect

    Aguado-Puente, P.; Bristowe, N. C.; Yin, B.; Shirasawa, R.; Ghosez, Philippe; Littlewood, P. B.; Artacho, Emilio

    2015-07-01

    The formation of a two-dimensional electron gas at oxide interfaces as a consequence of polar discontinuities has generated an enormous amount of activity due to the variety of interesting effects it gives rise to. Here, we study under what circumstances similar processes can also take place underneath ferroelectric thin films. We use a simple Landau model to demonstrate that in the absence of extrinsic screening mechanisms, a monodomain phase can be stabilized in ferroelectric films by means of an electronic reconstruction. Unlike in the LaAlO3/SrTiO3 heterostructure, the emergence with thickness of the free charge at the interface is discontinuous. This prediction is confirmed by performing first-principles simulations of free-standing slabs of PbTiO3. The model is also used to predict the response of the system to an applied electric field, demonstrating that the two-dimensional electron gas can be switched on and off discontinuously and in a nonvolatile fashion. Furthermore, the reversal of the polarization can be used to switch between a two-dimensional electron gas and a two-dimensional hole gas, which should, in principle, have very different transport properties. We discuss the possible formation of polarization domains and how such configuration competes with the spontaneous accumulation of free charge at the interfaces.

  4. Collapse of primordial gas clouds and the formation of quasar black holes

    NASA Technical Reports Server (NTRS)

    Loeb, Abraham; Rasio, Frederic A.

    1994-01-01

    The formation of quasar black holes during the hydrodynamic collapse of protogalactic gas clouds is discussed. The dissipational collapse and long-term dynamical evolution of these systems is analyzed using three-dimensional numerical simulations. The calculations focus on the final collapse stages of the inner baryonic component and therefore ignore the presence of dark matter. Two types of initial conditions are considered: uniformly rotating spherical clouds, and iirotational ellipsoidal clouds. In both cases the clouds are initially cold, homogeneous, and not far from rotational support (T/(absolute value of W) approximately equals 0.1). Although the details of the dynamical evolution depend sensitively on the initial conditions, the qualitative features of the final configurations do not. Most of the gas is found to fragment into small dense clumps, that eventually make up a spheroidal component resembling a galactic bulge. About 5% of the initial mass remains in the form of a smooth disk of gas supported by rotation in the gravitational potential potential well of the outer spheroid. If a central seed black hole of mass approximately greater than 10(exp 6) solar mass forms, it can grow by steady accretion from the disk and reach a typical quasar black hole mass approximately 10(exp 8) solar mass in less than 5 x 10(exp 8) yr. In the absence of a sufficiently massive seed, dynamical instabilities in a strongly self-gravitating inner region of the disk will inhibit steady accretion of gas and may prevent the immediate formation of quasar.

  5. Collapse of primordial gas clouds and the formation of quasar black holes

    NASA Technical Reports Server (NTRS)

    Loeb, Abraham; Rasio, Frederic A.

    1994-01-01

    The formation of quasar black holes during the hydrodynamic collapse of protogalactic gas clouds is discussed. The dissipational collapse and long-term dynamical evolution of these systems is analyzed using three-dimensional numerical simulations. The calculations focus on the final collapse stages of the inner baryonic component and therefore ignore the presence of dark matter. Two types of initial conditions are considered: uniformly rotating spherical clouds, and iirotational ellipsoidal clouds. In both cases the clouds are initially cold, homogeneous, and not far from rotational support (T/(absolute value of W) approximately equals 0.1). Although the details of the dynamical evolution depend sensitively on the initial conditions, the qualitative features of the final configurations do not. Most of the gas is found to fragment into small dense clumps, that eventually make up a spheroidal component resembling a galactic bulge. About 5% of the initial mass remains in the form of a smooth disk of gas supported by rotation in the gravitational potential potential well of the outer spheroid. If a central seed black hole of mass approximately greater than 10(exp 6) solar mass forms, it can grow by steady accretion from the disk and reach a typical quasar black hole mass approximately 10(exp 8) solar mass in less than 5 x 10(exp 8) yr. In the absence of a sufficiently massive seed, dynamical instabilities in a strongly self-gravitating inner region of the disk will inhibit steady accretion of gas and may prevent the immediate formation of quasar.

  6. Fiber optic sensing technology for detecting gas hydrate formation and decomposition.

    PubMed

    Rawn, C J; Leeman, J R; Ulrich, S M; Alford, J E; Phelps, T J; Madden, M E

    2011-02-01

    A fiber optic-based distributed sensing system (DSS) has been integrated with a large volume (72 l) pressure vessel providing high spatial resolution, time-resolved, 3D measurement of hybrid temperature-strain (TS) values within experimental sediment-gas hydrate systems. Areas of gas hydrate formation (exothermic) and decomposition (endothermic) can be characterized through this proxy by time series analysis of discrete data points collected along the length of optical fibers placed within a sediment system. Data are visualized as an animation of TS values along the length of each fiber over time. Experiments conducted in the Seafloor Process Simulator at Oak Ridge National Laboratory clearly indicate hydrate formation and dissociation events at expected pressure-temperature conditions given the thermodynamics of the CH(4)-H(2)O system. The high spatial resolution achieved with fiber optic technology makes the DSS a useful tool for visualizing time-resolved formation and dissociation of gas hydrates in large-scale sediment experiments.

  7. Fiber Optic Sensing Technology for Detecting Gas Hydrate Formation and Decomposition

    SciTech Connect

    Rawn, Claudia J; Leeman, John R; Ulrich, Shannon M; Alford, Jonathan E; Phelps, Tommy Joe; Madden, Megan Elwood

    2011-01-01

    A fiber optic-based distributed sensing system (DSS) has been integrated with a large volume (72 L) pressure vessel providing high spatial resolution, time resolved, 3-D measurement of hybrid temperature-strain (TS) values within experimental sediment gas hydrate systems. Areas of gas hydrate formation (exothermic) and decomposition (endothermic) can be characterized through this proxy by time series analysis of discrete data points collected along the length of optical fibers placed within a sediment system. Data is visualized as a 'movie' of TS values along the length of each fiber over time. Experiments conducted in the Seafloor Processing Simulator (SPS) at Oak Ridge National Laboratory show clear indications of hydrate formation and dissociation events at expected P-T conditions given the thermodynamics of the CH4-H2O system. The high spatial resolution achieved with fiber optic technology makes the DSS a useful tool for visualizing time resolved formation and dissociation of gas hydrates in large-scale sediment experiments.

  8. New quantum chemical computations of formamide deuteration support gas-phase formation of this prebiotic molecule

    NASA Astrophysics Data System (ADS)

    Skouteris, D.; Vazart, F.; Ceccarelli, C.; Balucani, N.; Puzzarini, C.; Barone, V.

    2017-06-01

    Based on recent work, formamide might be a potentially very important molecule in the emergence of terrestrial life. Although detected in the interstellar medium for decades, its formation route is still debated, whether in the gas phase or on the dust grain surfaces. Molecular deuteration has proven to be, in other cases, an efficient way to identify how a molecule is synthesized. For formamide, new published observations towards the IRAS16293-2422 B hot corino show that its three deuterated forms have all the same deuteration ratio, 2-5 per cent and that this is a factor of 3-8 smaller than that measured for H2CO towards the IRAS16293-2422 protostar. Following a previous work on the gas-phase formamide formation via the reaction NH2 + H2CO → HCONH2 + H, we present here new calculations of the rate coefficients for the production of monodeuterated formamide through the same reaction, starting from monodeuterated NH2 or H2CO. Some misconceptions regarding our previous treatment of the reaction are also cleared up. The results of the new computations show that, at the 100 K temperature of the hot corino, the rate of deuteration of the three forms is the same, within 20 per cent. On the contrary, the reaction between non-deuterated species proceeds three times faster than that with deuterated ones. These results confirm that a gas-phase route for the formation of formamide is perfectly in agreement with the available observations.

  9. Towards a multi-scale understanding of the gas-star formation cycle in the Central Molecular Zone

    NASA Astrophysics Data System (ADS)

    Kruijssen, J. M. Diederik

    2017-01-01

    The Central Molecular Zone (CMZ, the central 500 pc of the Milky Way) contains the largest reservoir of high-density molecular gas in the Galaxy, but forms stars at a rate 10-100 times below commonly-used star formation relations. We discuss recent efforts in understanding how the nearest galactic nucleus forms its stars. The latest models of the gas inflow, star formation, and feedback duty cycle reproduce the main observable features of the CMZ, showing that star formation is episodic and that the CMZ currently resides at a star formation minimum. Using orbital modelling, we derive the three-dimensional geometry of the CMZ and show how the orbital dynamics and the star formation potential of the gas are closely coupled. We discuss how this coupling reveals the physics of star formation and feedback under the conditions seen in high-redshift galaxies, and promotes the formation of the densest stellar clusters in the Galaxy.

  10. Testing the universality of the star-formation efficiency in dense molecular gas

    NASA Astrophysics Data System (ADS)

    Shimajiri, Y.; André, Ph.; Braine, J.; Könyves, V.; Schneider, N.; Bontemps, S.; Ladjelate, B.; Roy, A.; Gao, Y.; Chen, H.

    2017-08-01

    Context. Recent studies with, for example, Spitzer and Herschel have suggested that star formation in dense molecular gas may be governed by essentially the same "law" in Galactic clouds and external galaxies. This conclusion remains controversial, however, in large part because different tracers have been used to probe the mass of dense molecular gas in Galactic and extragalactic studies. Aims: We aimed to calibrate the HCN and HCO+ lines commonly used as dense gas tracers in extragalactic studies and to test the possible universality of the star-formation efficiency in dense gas (≳104 cm-3), SFEdense. Methods: We conducted wide-field mapping of the Aquila, Ophiuchus, and Orion B clouds at 0.04 pc resolution in the J = 1 - 0 transition of HCN, HCO+, and their isotopomers. For each cloud, we derived a reference estimate of the dense gas mass MHerschelAV > 8, as well as the strength of the local far-ultraviolet (FUV) radiation field, using Herschel Gould Belt survey data products, and estimated the star-formation rate from direct counting of the number of Spitzer young stellar objects. Results: The H13CO+(1-0) and H13CN(1-0) lines were observed to be good tracers of the dense star-forming filaments detected with Herschel. Comparing the luminosities LHCN and LHCO+ measured in the HCN and HCO+ lines with the reference masses MHerschelAV > 8, the empirical conversion factors αHerschel - HCN (=MHerschelAV > 8/LHCN) and αHerschel - HCO+ (=MHerschelAV > 8/LHCO+) were found to be significantly anti-correlated with the local FUV strength. In agreement with a recent independent study of Orion B by Pety et al., the HCN and HCO+ lines were found to trace gas down to AV ≳ 2. As a result, published extragalactic HCN studies must be tracing all of the moderate density gas down to nH2 ≲ 103 cm-3. Estimating the contribution of this moderate density gas from the typical column density probability distribution functions in nearby clouds, we obtained the following G0

  11. Brain Abscess in Solid Organ Transplant Recipients Receiving Cyclosporine-Based Immunosuppression

    PubMed Central

    Selby, Rick; Ramirez, Carlo B.; Singh, Reyka; Kleopoulos, Irene; Kusne, Shimon; Starzl, Thomas E.; Fung, John

    2010-01-01

    Objective To determine the incidence, clinical presentation, and outcome and confounding factors associated with the development of a brain abscess in solid organ transplant recipients. Design A 14-year retrospective survey. Setting A single, multiorgan, academic transplantation center. Patients A total of 2380 liver transplant recipients, 1650 kidney transplant recipients, and 598 heart, heart-lung, or lung transplant recipients of all ages (pediatric and adult) were included. All patients were given cyclosporine-based immunosuppression during this period. Main Outcome Measure A brain abscess was determined to be present if there was histological and/or microbiological confirmation of a brain lesion seen by a computed tomographic scan. A brain abscess was considered suspicious if radiographic findings were seen in the clinical setting of neurologic symptoms and fever without histological or microbiological confirmation. Results A brain abscess developed in a total of 28 patients (0.61%) of the total study population. The frequency of brain abscess according to organ type was as follows: 0.63%, liver; 0.36%, kidney; and 1.17%, heart and heart-lung. The overall mortality was 86%. Complicating factors associated with fungal (Candida and Aspergillus sp) abscess formation included major subsequent operations, retransplantations, antirejection therapy, associated bacteremia or viremia, and multiorgan failure. The lung was the primary site of dissemination in 18 patients. Low-dose prophylactic amphotericin was ineffective in preventing a fungal brain abscess in 10 high-risk patients. Because of the ineffective therapy and the deadly nature of established fungal abscesses, full-dose antifungal therapy and reduced immunosuppression were warranted on identification of a high-risk clinical setting. Nonfungal abscesses (Nocardia and Toxoplasma sp) occurred in healthy graft recipients long after transplantation. The existing medical therapy is usually effective in these

  12. In Situ Formation and Evolution of Gas Hydrates in Water-in-Oil Emulsions Using Pressure Rheometry

    NASA Astrophysics Data System (ADS)

    Rensing, P. J.; Liberatore, M. W.; Tonmukayakul, N.; Koh, C. A.; Sloan, E. D.

    2008-07-01

    In oil and gas production and transportation a major concern is the formation of gas hydrates (crystalline gas-water inclusion compounds that are stable at high pressures and low temperatures). Gas hydrates have a tenacious ability to plug pipelines, and may lead to unscheduled shut downs. The successful operation of pipeline transport with gas hydrates particles will depend on the ability to control gas hydrate agglomerations and depositions. Gas hydrates can be thermodynamically inhibited but this is proving cost ineffective and environmentally unfriendly. For this reason the oil/gas industry is moving to hydrate management rather than traditional methods of thermodynamic inhibition. One intriguing possibility would be to convert the water in the pipelines to non-agglomerating gas hydrates and then flow the slurry. However, this cannot be reliably achieved until basic understanding of hydrate slurry rheology is gained. To develop this fundamental understanding, in situ pressurized gas hydrate formation and rheological measurements from a water-in-oil emulsion have been conducted. In this work, small amplitude oscillatory and steady shear techniques have been used to characterize the rheological properties of these systems. The results demonstrate that hydrate formation can be detected in steady shear and oscillatory measurements, where a large viscosity (and elastic modulus) increase coincides with hydrate formation. Since temperature and pressure affect the thermodynamic stability of hydrates these are particular key variables that need to be tuned for this system.

  13. [Peri-hepatitis abscess secondary to pelvic peritonitis].

    PubMed

    Chevalier, N; De Tayrac, R; Dagher, I; Mockly, J F; Franco, D; Fernandez, H

    2002-11-01

    To report the case of a 42-year-old patient referred for exploration of a tumor of the right flank and evidence of inflammation. and methods. Ultrasonography and computed tomography showed a liver mass associated with a heterogeneous adnexal mass. Serum CA-125 was elevated and ovarian cancer with liver metastasis was suspected. An alternative diagnosis was salpingitis complicated by Fitz-Hugh-Curtis syndrome in this patient wearing an intra-uterine contraceptive device. Exploratory laparoscopy was performed and confirmed the diagnosis of salpingitis complicated by an ovarian abscess and Fitz-Hugh-Curtis syndrome with rare abscess formation. Outcome was favorable after adapted antibiotic treatment. Fitz-Hugh-Curtis syndrome can take on an atypical aspect and should be entertained as a possible diagnosis in young women presenting pain of the right flank and fever.

  14. Surgical treatment of a cerebral brain abscess in a cat.

    PubMed

    Wouters, E G H; Beukers, M; Theyse, L F H

    2011-01-01

    A nine-year-old male castrated European Shorthair cat was presented with a six-day history of progressive depression and ataxic gait. Neurological examination revealed depression, absent menace in the left eye, absent pupillary light reflex in the right eye, anisocoria, circling to the right, and delayed proprioception in all limbs. Magnetic resonance imaging showed a space-occupying right temporal lobe lesion adjacent to a small defect in the temporal bone suggestive of a meningo-encephalitis with concurrent abscess formation. The site was surgically approached by a rostrotentorial craniectomy. A cerebral abscess was found and debrided. Histopathological examination of the removed tissue demonstrated a subacute to chronic purulent encephalitis with extensive necrosis of brain tissue. Neurological symptoms resolved completely within two weeks and full recovery was observed four weeks after surgery.

  15. Brain abscess associated with cerebral amyloid angiopathy and hemorrhage.

    PubMed

    Wee, Hsiao-Yue; Wang, Che-Chuan; Li, Chien-Feng; Kuo, Jinn-Rung

    2011-06-01

    We want to report an extremely rare condition, brain abscess associated with cerebral amylid angiopathy and hemorrhage. We report on a 64-year-old woman who presented initially with moderate fever and headache. She was initially misdiagnosed with a bleeding tumor or arteriovenous malformation rupture and treated without antibiotic therapy. The mass was surgically drained due to neurological deterioration on day 14 after admission. Streptococcus virdians was isolated from the pus culture. The pathology evaluation showed cerebral amyloid angiopathy. She received intravenous antibiotic therapy for 4 weeks. She was eventually discharged home with left quadrantanopia. This case reminds us early recognition of brain abscess formation at the site of intracerebral hemorrhage is very important for prompt and appropriate treatment to improve the overall prognosis.

  16. Regulation of ice stream flow through subglacial formation of gas hydrates

    NASA Astrophysics Data System (ADS)

    Winsborrow, Monica; Andreassen, Karin; Hubbard, Alun; Plaza-Faverola, Andreia; Gudlaugsson, Eythor; Patton, Henry

    2016-05-01

    Variations in the flow of ice streams and outlet glaciers are a primary control on ice sheet stability, yet comprehensive understanding of the key processes operating at the ice-bed interface remains elusive. Basal resistance is critical, especially sticky spots--localized zones of high basal traction--for maintaining force balance in an otherwise well-lubricated/high-slip subglacial environment. Here we consider the influence of subglacial gas-hydrate formation on ice stream dynamics, and its potential to initiate and maintain sticky spots. Geophysical data document the geologic footprint of a major palaeo-ice-stream that drained the Barents Sea-Fennoscandian ice sheet approximately 20,000 years ago. Our results reveal a ~250 km2 sticky spot that coincided with subsurface shallow gas accumulations, seafloor fluid expulsion and a fault complex associated with deep hydrocarbon reservoirs. We propose that gas migrating from these reservoirs formed hydrates under high-pressure, low-temperature subglacial conditions. The gas hydrate desiccated, stiffened and thereby strengthened the subglacial sediments, promoting high traction--a sticky spot--that regulated ice stream flow. Deep hydrocarbon reservoirs are common beneath past and contemporary glaciated areas, implying that gas-hydrate regulation of subglacial dynamics could be a widespread phenomenon.

  17. Efficient and directed peptide bond formation in the gas phase via ion/ion reactions.

    PubMed

    McGee, William M; McLuckey, Scott A

    2014-01-28

    Amide linkages are among the most important chemical bonds in living systems, constituting the connections between amino acids in peptides and proteins. We demonstrate the controlled formation of amide bonds between amino acids or peptides in the gas phase using ion/ion reactions in a mass spectrometer. Individual amino acids or peptides can be prepared as reagents by (i) incorporating gas phase-labile protecting groups to silence otherwise reactive functional groups, such as the N terminus; (ii) converting the carboxyl groups to the active ester of N-hydroxysuccinimide; and (iii) incorporating a charge site. Protonation renders basic sites (nucleophiles) unreactive toward the N-hydroxysuccinimide ester reagents, resulting in sites with the greatest gas phase basicities being, in large part, unreactive. The N-terminal amines of most naturally occurring amino acids have lower gas phase basicities than the side chains of the basic amino acids (i.e., those of histidine, lysine, or arginine). Therefore, reagents may be directed to the N terminus of an existing "anchor" peptide to form an amide bond by protonating the anchor peptide's basic residues, while leaving the N-terminal amine unprotonated and therefore reactive. Reaction efficiencies of greater than 30% have been observed. We propose this method as a step toward the controlled synthesis of peptides in the gas phase.

  18. Natural gas production from Ordovician Queenston Formation in West Auburn field, Cayuga County, New York

    SciTech Connect

    Ward, T.L.

    1988-08-01

    Gas has been produced from the Upper Ordovician Queenston Formation at West Auburn field, Cayuga County, New York, for over 20 years. This field indicates Queenston production to be long lived, with substantially economic reserves found at depths shallower than 2,000 ft. Locally, The Queenston is comprised of sand and silty shale with the primary reservoirs found in quartzose sandstones. The overall thickness of the Queenston clastic interval is over 700 ft with gas found in the upper 300 ft. Three primary gas sands are continuous across the field area and have high average porosities of as much as 13.0% and average permeabilities of 0.20 md. Extreme examples show peak porosities approaching 20% and permeabilities of over 5.0 md. The reservoir is composed of very fine to medium-grained, moderately sorted, red sandstone. Sand grains are predominantly quartz with minor amounts of feldspar. The main pore-filling constituent is abundant authigenic clay with iron oxides, thus contributing to reduced permeabilities. These sands vary in reservoir quality through the field and, hence, allow for stratigraphic trapping of the gas. Other factors involved include the updip accumulation of gas against the Silurian-Ordovician unconformity at the top of the Queenston. Some of the pay sands are absent due to this unconformity in the area farthest updip and, therefore, decrease the overall reserve potential of the individual well in that part of the field.

  19. Formation resistivity measurements from within a cased well used to quantitatively determine the amount of oil and gas present

    DOEpatents

    Vail, III, William Banning

    2000-01-01

    Methods to quantitatively determine the separate amounts of oil and gas in a geological formation adjacent to a cased well using measurements of formation resistivity. The steps include obtaining resistivity measurements from within a cased well of a given formation, obtaining the porosity, obtaining the resistivity of formation water present, computing the combined amounts of oil and gas present using Archie's Equations, determining the relative amounts of oil and gas present from measurements within a cased well, and then quantitatively determining the separate amounts of oil and gas present in the formation. Resistivity measurements are obtained from within the cased well by conducting A.C. current from within the cased well to a remote electrode at a frequency that is within the frequency range of 0.1 Hz to 20 Hz.

  20. Investigating the role of gas bubble formation and entrapment in contaminated aquifers: Reactive transport modelling

    USGS Publications Warehouse

    Amos, Richard T.; Mayer, K. Ulrich

    2006-01-01

    In many natural and contaminated aquifers, geochemical processes result in the production or consumption of dissolved gases. In cases where methanogenesis or denitrification occurs, the production of gases may result in the formation and growth of gas bubbles below the water table. Near the water table, entrapment of atmospheric gases during water table rise may provide a significant source of O2 to waters otherwise depleted in O2. Furthermore, the presence of bubbles will affect the hydraulic conductivity of an aquifer, resulting in changes to the groundwater flow regime. The interactions between physical transport, biogeochemical processes, and gas bubble formation, entrapment and release is complex and requires suitable analysis tools. The objective of the present work is the development of a numerical model capable of quantitatively assessing these processes. The multicomponent reactive transport code MIN3P has been enhanced to simulate bubble growth and contraction due to in-situ gas production or consumption, bubble entrapment due to water table rise and subsequent re-equilibration of the bubble with ambient groundwater, and permeability changes due to trapped gas phase saturation. The resulting formulation allows for the investigation of complex geochemical systems where microbially mediated redox reactions both produce and consume gases as well as affect solution chemistry, alkalinity, and pH. The enhanced model has been used to simulate processes in a petroleum hydrocarbon contaminated aquifer where methanogenesis is an important redox process. The simulations are constrained by data from a crude oil spill site near Bemidji, MN. Our results suggest that permeability reduction in the methanogenic zone due to in-situ formation of gas bubbles, and dissolution of entrapped atmospheric bubbles near the water table, both work to attenuate the dissolved gas plume emanating from the source zone. Furthermore, the simulations demonstrate that under the given

  1. Investigating the role of gas bubble formation and entrapment in contaminated aquifers: Reactive transport modelling

    NASA Astrophysics Data System (ADS)

    Amos, Richard T.; Ulrich Mayer, K.

    2006-09-01

    In many natural and contaminated aquifers, geochemical processes result in the production or consumption of dissolved gases. In cases where methanogenesis or denitrification occurs, the production of gases may result in the formation and growth of gas bubbles below the water table. Near the water table, entrapment of atmospheric gases during water table rise may provide a significant source of O 2 to waters otherwise depleted in O 2. Furthermore, the presence of bubbles will affect the hydraulic conductivity of an aquifer, resulting in changes to the groundwater flow regime. The interactions between physical transport, biogeochemical processes, and gas bubble formation, entrapment and release is complex and requires suitable analysis tools. The objective of the present work is the development of a numerical model capable of quantitatively assessing these processes. The multicomponent reactive transport code MIN3P has been enhanced to simulate bubble growth and contraction due to in-situ gas production or consumption, bubble entrapment due to water table rise and subsequent re-equilibration of the bubble with ambient groundwater, and permeability changes due to trapped gas phase saturation. The resulting formulation allows for the investigation of complex geochemical systems where microbially mediated redox reactions both produce and consume gases as well as affect solution chemistry, alkalinity, and pH. The enhanced model has been used to simulate processes in a petroleum hydrocarbon contaminated aquifer where methanogenesis is an important redox process. The simulations are constrained by data from a crude oil spill site near Bemidji, MN. Our results suggest that permeability reduction in the methanogenic zone due to in-situ formation of gas bubbles, and dissolution of entrapped atmospheric bubbles near the water table, both work to attenuate the dissolved gas plume emanating from the source zone. Furthermore, the simulations demonstrate that under the given

  2. How Sodium Chloride Salt Inhibits the Formation of CO2 Gas Hydrates.

    PubMed

    Holzammer, Christine; Finckenstein, Agnes; Will, Stefan; Braeuer, Andreas S

    2016-03-10

    We present an experimental Raman study on how the addition of sodium chloride to CO2-hydrate-forming systems inhibits the hydrate formation thermodynamically. For this purpose, the molar enthalpy of reaction and the molar entropy of reaction for the reaction of weakly hydrogen-bonded water molecules to strongly hydrogen bonded water molecules are determined for different salinities from the Raman spectrum of the water-stretching vibration. Simultaneously, the influence of the salinity on the solubility of CO2 in the liquid water-rich phase right before the start of hydrate formation is analyzed. The results demonstrate that various mechanisms contribute to the inhibition of gas hydrate formation. For the highest salt concentration of 20 wt % investigated, the temperature of gas hydrate formation is lowered by 12 K. For this concentration the molar enthalpy and entropy of reaction become smaller by 50 and 20%, respectively. Concurrently, the solubility of carbon dioxide is reduced by 70%. These results are compared with data in literature for systems of sodium chloride in water (without carbon dioxide).

  3. Complex Organic Molecules Formation in Space Through Gas Phase Reactions: A Theoretical Approach

    NASA Astrophysics Data System (ADS)

    Redondo, Pilar; Barrientos, Carmen; Largo, Antonio

    2017-02-01

    Chemistry in the interstellar medium (ISM) is capable of producing complex organic molecules (COMs) of great importance to astrobiology. Gas phase and grain surface chemistry almost certainly both contribute to COM formation. Amino acids as building blocks of proteins are some of the most interesting COMs. The simplest one, glycine, has been characterized in meteorites and comets and, its conclusive detection in the ISM seems to be highly plausible. In this work, we analyze the gas phase reaction of glycine and {{{CH}}5}+ to establish the role of this process in the formation of alanine or other COMs in the ISM. Formation of protonated α- and β-alanine in spite of being exothermic processes is not viable under interstellar conditions because the different paths leading to these isomers present net activation energies. Nevertheless, glycine can evolve to protonated 1-imide-2, 2-propanediol, protonated amino acetone, protonated hydroxyacetone, and protonated propionic acid. However, formation of acetic acid and protonated methylamine is also a favorable process and therefore will be a competitive channel with the evolution of glycine to COMs.

  4. Estimating Depth and Producing Formations of Abandoned Oil and Gas Wells Using Geospatial Analysis

    NASA Astrophysics Data System (ADS)

    Christian, S.; Kang, M.; Celia, M. A.; Maloof, A. C.; Mauzerall, D. L.

    2015-12-01

    More than three million abandoned oil and gas wells exist in the U.S., and information on many of these wells are lost. Recent measurements of 93 abandoned wells in Pennsylvania show that they may be a significant source of methane emissions to the atmosphere. Data such as depth and producing formation of 98% of these measured wells are unavailable. Information on the likely depth of the well and the formation, from which the well likely produced from, is important when evaluating the wells' potential to emit methane and/or to contaminate overlying aquifers, and when developing mitigation strategies. We use geospatial analysis that combines available public databases from the Pennsylvania Department of Environmental Protection and historic documents to determine the likely depth and formation from which the measured abandoned wells produced. We develop a framework to systematically evaluate the nearest well, pool, and field attributes and assign depth and producing formation to the measured wells based on how well these attributes match. We then use this information to perform a cost analysis for plugging based on well depth for Pennsylvania. The geospatial analysis framework presented here for determining abandoned well properties can be valuable for future field measurement designs, upscaling methane emissions, and mitigating abandoned wells in Pennsylvania but also the many other states with a long history of oil and gas production.

  5. Psoas abscess in an immunocompetent host.

    PubMed

    Mannino, Courtney M; Salhab, Mohammed; Schmidhofer, Sarah; Pop-Vicas, Aurora

    2014-08-01

    We present a case of iliopsoas abscess in an immunocompetent patient. She experienced three weeks of worsening right hip pain, which was initially misdiagnosed as degenerative joint disease. This led to admission to the Intensive Care Unit for severe sepsis. The patient improved with intravenous antibiotics and percutaneous abscess drainage.

  6. Microbiology and treatment of acute apical abscesses.

    PubMed

    Siqueira, José F; Rôças, Isabela N

    2013-04-01

    Acute apical abscess is the most common form of dental abscess and is caused by infection of the root canal of the tooth. It is usually localized intraorally, but in some cases the apical abscess may spread and result in severe complications or even mortality. The reasons why dental root canal infections can become symptomatic and evolve to severe spreading and sometimes life-threatening abscesses remain elusive. Studies using culture and advanced molecular microbiology methods for microbial identification in apical abscesses have demonstrated a multispecies community conspicuously dominated by anaerobic bacteria. Species/phylotypes commonly found in these infections belong to the genera Fusobacterium, Parvimonas, Prevotella, Porphyromonas, Dialister, Streptococcus, and Treponema. Advances in DNA sequencing technologies and computational biology have substantially enhanced the knowledge of the microbiota associated with acute apical abscesses and shed some light on the etiopathogeny of this disease. Species richness and abundance and the resulting network of interactions among community members may affect the collective pathogenicity and contribute to the development of acute infections. Disease modifiers, including transient or permanent host-related factors, may also influence the development and severity of acute abscesses. This review focuses on the current evidence about the etiology and treatment of acute apical abscesses and how the process is influenced by host-related factors and proposes future directions in research, diagnosis, and therapeutic approaches to deal with this disease.

  7. Unusual complication of dental extraction: lingual abscess.

    PubMed

    Varghese, Lalee; Agarwal, Pratibha; Rupa, Vedantam

    2013-01-01

    Acute lingual swelling is a potentially life threatening clinical condition which is encountered very rarely, the differential diagnosis of which includes hemorrhage, infarction, abscess, tumor and edema. Herein we report a case of lingual abscess that presented with acute tongue swelling and respiratory distress after extraction of lower two incisor teeth.

  8. Liver Abscess: Increasing Occurrence in Premature Newborns

    PubMed Central

    Bosnalı, Oktav; Moralıoğlu, Serdar; Pektaş, Osman

    2013-01-01

    Neonatal liver abscess is a very rare condition associated with high morbidity and mortality rates. There seems to be an increasing trend of this rare condition amongst the newborns admitted to neonatal intensive care units. We report a case of liver abscess in a premature newborn and briefly review the literature and discuss its management. PMID:26023443

  9. Video-assisted hepatic abscess debridement

    PubMed Central

    Klink, Christian D; Binnebösel, Marcel; Schmeding, Maximilian; van Dam, Ronald M; Dejong, Cornelis H; Junge, Karsten; Neumann, Ulf P

    2015-01-01

    Background Pyogenic liver abscesses are currently treated by either percutaneous computer tomography (CT)-guided drainage or by laparoscopic and a conventional liver resection when conservative treatment fails but may be associated with substantial morbidity and mortality. Methods A minimally invasive technique involving debridement of right liver abscesses was employed using a minimally invasive video-assisted hepatic abscess debridement (VAHD) after unsuccessful percutaneous CT-guided drainage. Clinical data, complication rates and outcomes of patients were recorded retrospectively. Results Between 2011 and 2014, VAHD was performed on 10 patients at two centres with no observed recurrence of a liver abscess. The median age of the patients was 57 years (range 42–78) with a median pre-operative size of a liver abscess of 78 mm (range 40–115). The median operation time was 47 min (range 23–75), and the median postoperative hospital stay was 9 days (range 7–69). One patient developed a subcutaneous abscess that required further surgery. No patient died, and there were no major complications related to the VAHD. Conclusions Video-assisted hepatic abscess debridement is a feasible technique that shows promising results for the treatment of a recurrent right liver abscess. PMID:26096195

  10. Video-assisted hepatic abscess debridement.

    PubMed

    Klink, Christian D; Binnebösel, Marcel; Schmeding, Maximilian; van Dam, Ronald M; Dejong, Cornelis H; Junge, Karsten; Neumann, Ulf P

    2015-08-01

    Pyogenic liver abscesses are currently treated by either percutaneous computer tomography (CT)-guided drainage or by laparoscopic and a conventional liver resection when conservative treatment fails but may be associated with substantial morbidity and mortality. A minimally invasive technique involving debridement of right liver abscesses was employed using a minimally invasive video-assisted hepatic abscess debridement (VAHD) after unsuccessful percutaneous CT-guided drainage. Clinical data, complication rates and outcomes of patients were recorded retrospectively. Between 2011 and 2014, VAHD was performed on 10 patients at two centres with no observed recurrence of a liver abscess. The median age of the patients was 57 years (range 42-78) with a median pre-operative size of a liver abscess of 78 mm (range 40-115). The median operation time was 47 min (range 23-75), and the median postoperative hospital stay was 9 days (range 7-69). One patient developed a subcutaneous abscess that required further surgery. No patient died, and there were no major complications related to the VAHD. Video-assisted hepatic abscess debridement is a feasible technique that shows promising results for the treatment of a recurrent right liver abscess. © 2015 International Hepato-Pancreato-Biliary Association.

  11. Microbiology and Treatment of Acute Apical Abscesses

    PubMed Central

    Rôças, Isabela N.

    2013-01-01

    SUMMARY Acute apical abscess is the most common form of dental abscess and is caused by infection of the root canal of the tooth. It is usually localized intraorally, but in some cases the apical abscess may spread and result in severe complications or even mortality. The reasons why dental root canal infections can become symptomatic and evolve to severe spreading and sometimes life-threatening abscesses remain elusive. Studies using culture and advanced molecular microbiology methods for microbial identification in apical abscesses have demonstrated a multispecies community conspicuously dominated by anaerobic bacteria. Species/phylotypes commonly found in these infections belong to the genera Fusobacterium, Parvimonas, Prevotella, Porphyromonas, Dialister, Streptococcus, and Treponema. Advances in DNA sequencing technologies and computational biology have substantially enhanced the knowledge of the microbiota associated with acute apical abscesses and shed some light on the etiopathogeny of this disease. Species richness and abundance and the resulting network of interactions among community members may affect the collective pathogenicity and contribute to the development of acute infections. Disease modifiers, including transient or permanent host-related factors, may also influence the development and severity of acute abscesses. This review focuses on the current evidence about the etiology and treatment of acute apical abscesses and how the process is influenced by host-related factors and proposes future directions in research, diagnosis, and therapeutic approaches to deal with this disease. PMID:23554416

  12. Tundish Open Eye Formation in Inert Gas-Shrouded Tundishes: A Macroscopic Model from First Principles

    NASA Astrophysics Data System (ADS)

    Chatterjee, Saikat; Chattopadhyay, Kinnor

    2016-10-01

    Open eye formation in tundishes can result in reoxidation of liquid steel leading to the formation of harmful inclusions. Moreover, it is also a site for heat loss, gas absorption, and slag emulsification. All these factors make it necessary to understand the fundamentals of open eye formation, which in turn will allow us to prevent or control its harmful effects. In the present study, the bubble plume regions in a ladle and tundish were compared, and it was observed that there are significant differences between the two. Moreover, a simplistic model for predicting the open eye area in tundishes for `thin slag' practices was derived using the principles of conservation of mass and momentum. The proposed model was able to predict open eye areas in tundish reasonably well and was compared with other models, and experimental results.

  13. Galaxy Mergers with Adaptive Mesh Refinement: Star Formation and Hot Gas Outflow

    SciTech Connect

    Kim, Ji-hoon; Wise, John H.; Abel, Tom; /KIPAC, Menlo Park /Stanford U., Phys. Dept.

    2011-06-22

    In hierarchical structure formation, merging of galaxies is frequent and known to dramatically affect their properties. To comprehend these interactions high-resolution simulations are indispensable because of the nonlinear coupling between pc and Mpc scales. To this end, we present the first adaptive mesh refinement (AMR) simulation of two merging, low mass, initially gas-rich galaxies (1.8 x 10{sup 10} M{sub {circle_dot}} each), including star formation and feedback. With galaxies resolved by {approx} 2 x 10{sup 7} total computational elements, we achieve unprecedented resolution of the multiphase interstellar medium, finding a widespread starburst in the merging galaxies via shock-induced star formation. The high dynamic range of AMR also allows us to follow the interplay between the galaxies and their embedding medium depicting how galactic outflows and a hot metal-rich halo form. These results demonstrate that AMR provides a powerful tool in understanding interacting galaxies.

  14. Method for reducing sulfate formation during regeneration of hot-gas desulfurization sorbents

    DOEpatents

    Bissett, Larry A.; Strickland, Larry D.; Rockey, John M.

    1994-01-01

    The regeneration of sulfur sorbents having sulfate forming tendencies and used for desulfurizing hot product gas streams such as provided by coal gasification is provided by employing a two-stage regeneration method. Air containing a sub-stoichiometric quantity of oxygen is used in the first stage for substantially fully regenerating the sorbent without sulfate formation and then regeneration of the resulting partially regenerated sorbent is completed in the second stage with air containing a quantity of oxygen slightly greater than the stoichiometric amount adequate to essentially fully regenerate the sorbent. Sulfate formation occurs in only the second stage with the extent of sulfate formation being limited only to the portion of the sulfur species contained by the sorbent after substantially all of the sulfur species have been removed therefrom in the first stage.

  15. Disseminated tuberculosis with prostatic abscesses in an immunocompromised patient-A case report and review of literature.

    PubMed

    Joneja, Upasana; Short, William R; Roberts, Amity L

    2016-01-01

    We describe a case of disseminated Mycobacterium tuberculosis (mTB) with prostatic abscess in a newly diagnosed HIV patient in the United States. The patient is a 34 year-old male who presented with respiratory symptoms and was diagnosed with HIV/AIDS complicated by disseminated mTB infection of the lungs, liver, and prostate. His prostate showed abscess formation on imaging that required drainage however he did not present with any genitourinary complaints. Our literature review revealed that prostatic involvement in mTB in the form of granulomatous prostatitis is uncommon; however, abscess formation is extremely rare and only few such cases have been published. Nearly 50% of the patients with prostatic abscess formation present without symptoms and therefore a high level of suspicion should be maintained; imaging should be performed early and prophylactic antibiotics for non-specific urinary symptoms should be avoided as this may lead to drug resistance of mTB to flouroquinolones.

  16. Mud volcano venting induced gas hydrate formation at the upper slope accretionary wedge, offshore SW Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Saulwood; Tseng, Yi-Ting; Cheng, Wan-Yen; Chou, Cheng-Tien; Chen, NeiChen; Hsieh, I.-Chih

    2016-04-01

    chloride indicated gas hydrate formation in sediments away from the mud volcano cone.

  17. Formation of Small Gas Phase Carbonyls from Heterogeneous Oxidation of Polyunsaturated Fatty Acids (PUFA)

    NASA Astrophysics Data System (ADS)

    Zhou, S.; Zhao, R.; Lee, A.; Gao, S.; Abbatt, J.

    2011-12-01

    Fatty acids (FAs) are emitted into the atmosphere from gas and diesel powered vehicles, cooking, plants, and marine biota. Field measurements have suggested that FAs, including polyunsaturated fatty acids (PUFA), could make up an important contribution to the organic fraction of atmospheric aerosols. Due to the existence of carbon-carbon double bonds in their molecules, PUFA are believed to be highly reactive towards atmospheric oxidants such as OH and NO3 radicals and ozone, which will contribute to aerosol hygroscopicity and cloud condensation nuclei activity. Previous work from our group has shown that small carbonyls formed from the heterogeneous reaction of linoleic acid (LA) thin films with gas-phase O3. It is known that the formation of small carbonyls in the atmosphere is not only relevant to the atmospheric budget of volatile organic compounds but also to secondary organic aerosol formation. In the present study, using an online proton transfer reaction mass spectrometry (PTR-MS) and off-line gas chromatography-mass spectrometry (GC-MS) we again investigated carbonyl formation from the same reaction system, i.e. the heterogeneous ozonolysis of LA film. In addition to the previously reported carbonyls, malondialdehyde (MDA), a source of reactive oxygen species that is mutagenic, has been identified as a product for the first time. Small dicarbonyls, e.g. glyoxal, are expected to be formed from the further oxidation of MDA. In this presentation, the gas-phase chemistry of MDA with OH radicals using a newly built Teflon chamber in our group will also be presented.

  18. Using direct imaging to investigate the formation and migration histories of gas giant exoplanets

    NASA Astrophysics Data System (ADS)

    Ngo, Henry

    2016-10-01

    Gas giant exoplanets are found around their host stars at orbital separations spanning more than four orders of magnitude (0.01 to 100 AU). However, it is not known whether the planets at the extreme ends of this range could have formed in situ or if they instead formed closer to ice lines between 1-10 AU and then migrated to their present day locations. In this study, we use two direct imaging surveys to explore the potential origins of hot Jupiters and to characterize the population of gas giant planets beyond the ice line. In our first survey, we focus on the role of stellar companions in hot Jupiter formation and migration. We determine that less than 20% of hot Jupiters have stellar companions capable of inducing migration via Kozai-Lidov oscillations. In addition, we find that hot Jupiter hosts are three times more likely to have a stellar companion between 50-2000 AU than field stars, suggesting that binary star systems may be favorable environments for gas giant planet formation. In our second study, we present the results from the first year of a two-year direct imaging planet survey of 200 young M-dwarf stars. By imaging in L-band (3.8 micron) and taking advantage of the new 80 milliarcsecond inner working angle "vortex" coronagraph on Keck NIRC2, we are sensitive to young planets with masses between 1-10 Jupiter masses with projected separations between 1-10 AU. We can compare the semi-major axis distribution of directly imaged planets beyond 10 AU to that of intermediate period gas giants from radial velocity surveys and determine whether or not these two populations form a continuous distribution. If so, this would imply these populations share common formation (core accretion) and migration channels.

  19. Using direct imaging to investigate the formation and migration histories of gas giant exoplanets

    NASA Astrophysics Data System (ADS)

    Ngo, Henry

    2017-01-01

    Gas giant exoplanets are found around their host stars at orbital separations spanning more than four orders of magnitude (0.01 to 100 AU). However, it is not known whether the planets at the extreme ends of this range could have formed in situ or if they instead formed closer to ice lines between 1-10 AU and then migrated to their present day locations. In this study, we use two direct imaging surveys to explore the potential origins of hot Jupiters and to characterize the population of gas giant planets beyond the ice line. In our first survey, we focus on the role of stellar companions in hot Jupiter formation and migration. We determine that less than 20% of hot Jupiters have stellar companions capable of inducing migration via Kozai-Lidov oscillations. In addition, we find that hot Jupiter hosts are three times more likely to have a stellar companion between 50-2000 AU than field stars, suggesting that binary star systems may be favorable environments for gas giant planet formation. In our second study, we present the results from the first year of a two-year direct imaging planet survey of 200 young M-dwarf stars. By imaging in L-band (3.8 micron) and taking advantage of the new 80 milliarcsecond inner working angle "vortex" coronagraph on Keck NIRC2, we are sensitive to young planets with masses between 1-10 Jupiter masses with projected separations between 1-10 AU. We can compare the semi-major axis distribution of directly imaged planets beyond 10 AU to that of intermediate period gas giants from radial velocity surveys and determine whether or not these two populations form a continuous distribution. If so, this would imply these populations share common formation (core accretion) and migration channels.

  20. Increasing Gas Hydrate Formation Temperature for Desalination of High Salinity Produced Water with Secondary Guests

    SciTech Connect

    Cha, Jong-Ho; Seol, Yongkoo

    2013-10-07

    We suggest a new gas hydrate-based desalination process using water-immiscible hydrate formers; cyclopentane (CP) and cyclohexane (CH) as secondary hydrate guests to alleviate temperature requirements for hydrate formation. The hydrate formation reactions were carried out in an isobaric condition of 3.1 MPa to find the upper temperature limit of CO2 hydrate formation. Simulated produced water (8.95 wt % salinity) mixed with the hydrate formers shows an increased upper temperature limit from -2 °C for simple CO2 hydrate to 16 and 7 °C for double (CO2 + CP) and (CO2 + CH) hydrates, respectively. The resulting conversion rate to double hydrate turned out to be similar to that with simple CO2 hydrate at the upper temperature limit. Hydrate formation rates (Rf) for the double hydrates with CP and CH are shown to be 22 and 16 times higher, respectively, than that of the simple CO2 hydrate at the upper temperature limit. Such mild hydrate formation temperature and fast formation kinetics indicate increased energy efficiency of the double hydrate system for the desalination process. Dissociated water from the hydrates shows greater than 90% salt removal efficiency for the hydrates with the secondary guests, which is also improved from about 70% salt removal efficiency for the simple hydrates.

  1. Crackling sound generation during the formation of liquid bridges: A lattice gas model

    NASA Astrophysics Data System (ADS)

    Almeida, Alexandre B.; Buldyrev, Sergey V.; Alencar, Adriano M.

    2013-08-01

    Due to abnormal mechanical instabilities, liquid bridges may form in the small airways blocking airflow. Liquid bridge ruptures during inhalation are the major cause of the crackling adventitious lung sound, which can be heard using a simple stethoscope. Recently, Vyshedskiy and colleagues (2009) [1] described and characterized a crackle sound originated during expiration. However, the mechanism and origin of the expiratory crackle are still controversial. Thus, in this paper, we propose a mechanism for expiratory crackles. We hypothesize that the expiratory crackle sound is a result of the energy released in the form of acoustic waves during the formation of the liquid bridge. The magnitude of the energy released is proportional to the difference in free energy prior and after the bridge formation. We use a lattice gas model to describe the liquid bridge formation between two parallel planes. Specifically, we determine the surface free energy and the conditions of the liquid bridge formation between two parallel planes separated by a distance 2h by a liquid droplet of volume Ω and contact angle Θ, using both Monte Carlo simulation of a lattice gas model and variational calculus based on minimization of the surface area with the volume and the contact angle constrained. We numerically and analytically determine the phase diagram of the system as a function of the dimensionless parameter hΩ and Θ. We can distinguish two different phases: one droplet and one liquid bridge. We observe a hysteresis curve for the energy changes between these two states, and a finite size effect in the bridge formation. We compute the release of free energy during the formation of the liquid bridge and discuss the results in terms of system size. We also calculate the force exerted from liquid bridge on the planes by studying the dependence of the free energy on the separation between the planes 2h. The simulation results are in agreement with the analytical solution.

  2. Understanding Passive Layer Formation for Further Corrosion Management in Gas Production Pipes

    NASA Astrophysics Data System (ADS)

    Santoso, R. K.; Rahmawati, S. D.; Gadesa, A.; Wahyuningrum, D.

    2017-07-01

    Corrosion is a critical issue during the development of a gas field, especially wet gas or retrograde gas field. Corrosion affects the management system of a field and further impacts the amount of investment. Therefore, accurate prediction of corrosion rate is needed to plan an effective preventive action before going further to the development phase. One of the important parameters that should be noticed to create an accurate prediction is the formation of the passive layer. In CO2-H2S environment, there will be three possibilities of passive layer: FeS, FeCO3 or no passive layer. In this study, we create mathematical models to determine the formed passive layer in each segment of the gas production tubing and pipeline. The model is built using Faraday’s Law and Thermodynamic approach to account the passive layer formation at different temperature, pH, corrosion rate and partial pressure of CO2 and H2S. From the simulation, it was found that there were three boundary conditions: no scale-FeS boundary, no scale-FeCO3 boundary and FeS-FeCO3 boundary. The first two boundaries evolved over a time as the concentration of Fe2+ ions was increasing. However, FeS-FeCO3 boundary remained steady as it was not affected by the addition of Fe2+ ions. Using sample case study, few variations were noticed at production pipeline and tubing. It was caused by the gas composition, which contained high CO2 and very low H2S. Boundary conditions only changed slightly over two days period.

  3. The microbiology of the acute dental abscess.

    PubMed

    Robertson, D; Smith, A J

    2009-02-01

    The acute dental abscess is frequently underestimated in terms of its morbidity and mortality. The risk of potential serious consequences arising from the spread of a dental abscess is still relevant today with many hospital admissions for dental sepsis. The acute dental abscess is usually polymicrobial comprising facultative anaerobes, such as viridans group streptococci and the Streptococcus anginosus group, with predominantly strict anaerobes, such as anaerobic cocci, Prevotella and Fusobacterium species. The use of non-culture techniques has expanded our insight into the microbial diversity of the causative agents, identifying such organisms as Treponema species and anaerobic Gram-positive rods such as Bulleidia extructa, Cryptobacterium curtum and Mogibacterium timidum. Despite some reports of increasing antimicrobial resistance in isolates from acute dental infection, the vast majority of localized dental abscesses respond to surgical treatment, with antimicrobials limited to spreading and severe infections. The microbiology and treatment of the acute localized abscess and severe spreading odontogenic infections are reviewed.

  4. Postlumbar puncture arachnoiditis mimicking epidural abscess

    PubMed Central

    Gürbüz, Mehmet Sabri; Erdoğan, Barıs; Yüksel, Mehmet Onur; Somay, Hakan

    2013-01-01

    Lumbar spinal arachnoiditis occurring after diagnostic lumbar puncture is a very rare condition. Arachnoiditis may also present with fever and elevated infection markers and may mimic epidural abscess, which is one of the well known infectious complications of lumbar puncture. We report the case of a 56-year-old man with lumbar spinal arachnoiditis occurring after diagnostic lumbar puncture who was operated on under a misdiagnosis of epidural abscess. In the intraoperative and postoperative microbiological and histopathological examination, no epidural abscess was detected. To our knowledge, this is the first case of a patient with postlumbar puncture arachnoiditis operated on under a misdiagnosis of epidural abscess reported in the literature. The authors suggest that arachnoiditis may mimic epidural abscess due to its clinical and radiological features and should be considered in the differential diagnosis of complications of lumbar puncture. PMID:24197809

  5. The formation of submillimetre-bright galaxies from gas infall over a billion years.

    PubMed

    Narayanan, Desika; Turk, Matthew; Feldmann, Robert; Robitaille, Thomas; Hopkins, Philip; Thompson, Robert; Hayward, Christopher; Ball, David; Faucher-Giguère, Claude-André; Kereš, Dušan

    2015-09-24

    Submillimetre-bright galaxies at high redshift are the most luminous, heavily star-forming galaxies in the Universe and are characterized by prodigious emission in the far-infrared, with a flux of at least five millijanskys at a wavelength of 850 micrometres. They reside in haloes with masses about 10(13) times that of the Sun, have low gas fractions compared to main-sequence disks at a comparable redshift, trace complex environments and are not easily observable at optical wavelengths. Their physical origin remains unclear. Simulations have been able to form galaxies with the requisite luminosities, but have otherwise been unable to simultaneously match the stellar masses, star formation rates, gas fractions and environments. Here we report a cosmological hydrodynamic galaxy formation simulation that is able to form a submillimetre galaxy that simultaneously satisfies the broad range of observed physical constraints. We find that groups of galaxies residing in massive dark matter haloes have increasing rates of star formation that peak at collective rates of about 500-1,000 solar masses per year at redshifts of two to three, by which time the interstellar medium is sufficiently enriched with metals that the region may be observed as a submillimetre-selected system. The intense star formation rates are fuelled in part by the infall of a reservoir gas supply enabled by stellar feedback at earlier times, not through major mergers. With a lifetime of nearly a billion years, our simulations show that the submillimetre-bright phase of high-redshift galaxies is prolonged and associated with significant mass buildup in early-Universe proto-clusters, and that many submillimetre-bright galaxies are composed of numerous unresolved components (for which there is some observational evidence).

  6. GAS RESERVOIRS AND STAR FORMATION IN A FORMING GALAXY CLUSTER AT zbsime0.2

    SciTech Connect

    Jaffe, Yara L.; Poggianti, Bianca M.; Verheijen, Marc A. W.; Deshev, Boris Z.; Van Gorkom, Jacqueline H.

    2012-09-10

    We present first results from the Blind Ultra-Deep H I Environmental Survey of the Westerbork Synthesis Radio Telescope. Our survey is the first direct imaging study of neutral atomic hydrogen gas in galaxies at a redshift where evolutionary processes begin to show. In this Letter we investigate star formation, H I content, and galaxy morphology, as a function of environment in Abell 2192 (at z = 0.1876). Using a three-dimensional visualization technique, we find that Abell 2192 is a cluster in the process of forming, with significant substructure in it. We distinguish four structures that are separated in redshift and/or space. The richest structure is the baby cluster itself, with a core of elliptical galaxies that coincides with (weak) X-ray emission, almost no H I detections, and suppressed star formation. Surrounding the cluster, we find a compact group where galaxies pre-process before falling into the cluster, and a scattered population of 'field-like' galaxies showing more star formation and H I detections. This cluster proves to be an excellent laboratory to understand the fate of the H I gas in the framework of galaxy evolution. We clearly see that the H I gas and the star formation correlate with morphology and environment at z {approx} 0.2. In particular, the fraction of H I detections is significantly affected by the environment. The effect starts to kick in in low-mass groups that pre-process the galaxies before they enter the cluster. Our results suggest that by the time the group galaxies fall into the cluster, they are already devoid of H I.

  7. A dynamical model for gas flows, star formation and nuclear winds in galactic centres

    NASA Astrophysics Data System (ADS)

    Krumholz, Mark R.; Kruijssen, J. M. Diederik; Crocker, Roland M.

    2017-04-01

    We present a dynamical model for gas transport, star formation and winds in the nuclear regions of galaxies, focusing on the Milky Way's Central Molecular Zone (CMZ). In our model angular momentum and mass are transported by a combination of gravitational and bar-driven acoustic instabilities. In gravitationally unstable regions the gas can form stars, and the resulting feedback drives both turbulence and a wind that ejects mass from the CMZ. We show that the CMZ is in a quasi-steady state where mass deposited at large radii by the bar is transported inwards to a star-forming, ring-shaped region at ∼100 pc from the Galactic Centre, where the shear reaches a minimum. This ring undergoes episodic starbursts, with bursts lasting ∼5-10 Myr occurring at ∼20-40 Myr intervals. During quiescence the gas in the ring is not fully cleared, but is driven out of a self-gravitating state by the momentum injected by expanding supernova remnants. Starbursts also drive a wind off the star-forming ring, with a time-averaged mass flux comparable to the star formation rate. We show that our model agrees well with the observed properties of the CMZ, and places it near a star formation minimum within the evolutionary cycle. We argue that such cycles of bursty star formation and winds should be ubiquitous in the nuclei of barred spiral galaxies, and show that the resulting distribution of galactic nuclei on the Kennicutt-Schmidt relation is in good agreement with that observed in nearby galaxies.

  8. High occurrence of perianal abscess among Bedouin compared to Jews in the southern region of Israel

    PubMed Central

    2013-01-01

    Background This study assessed the ethnic differences of perianal abscess between Bedouin and the general population in southern region of Israel. Israeli-born Arabs have much less colorectal cancer than Israeli-born Jews. It is not clear whether other colorectal diseases have the same ethnic occurrence. Method This is a retrospective case series of patients who had perianal abscess. Patients' demographics, managements and course of disease were analyzed. Results Bedouin male constituted 29.7% of all patients, while they constitute only 15.7% of the population relative risk of 2.27 (p< 0. 001). 16.4% of the patients experienced perianal abscess recurrence. 39% of the males with recurrent abscess formation were Bedouin, relative risk of 1.8 (p<0. 001). Conclusion Bedouin males have high relative risk to develop perianal abscess. Bedouin males as others with first recurrence have high relative risk for recurrence. Thus for both groups of patients, there is an indication to operate in order to treat the abscess and coexisting fistula. PMID:24028279

  9. High occurrence of perianal abscess among Bedouin compared to Jews in the southern region of Israel.

    PubMed

    Czeiger, David; Shaked, Gad; Igov, Igor; Pinsk, Ilia; Peiser, Jochanan; Sebbag, Gilbert

    2013-09-12

    This study assessed the ethnic differences of perianal abscess between Bedouin and the general population in southern region of Israel. Israeli-born Arabs have much less colorectal cancer than Israeli-born Jews. It is not clear whether other colorectal diseases have the same ethnic occurrence. This is a retrospective case series of patients who had perianal abscess. Patients' demographics, managements and course of disease were analyzed. Bedouin male constituted 29.7% of all patients, while they constitute only 15.7% of the population relative risk of 2.27 (p< 0. 001). 16.4% of the patients experienced perianal abscess recurrence. 39% of the males with recurrent abscess formation were Bedouin, relative risk of 1.8 (p<0. 001). Bedouin males have high relative risk to develop perianal abscess. Bedouin males as others with first recurrence have high relative risk for recurrence. Thus for both groups of patients, there is an indication to operate in order to treat the abscess and coexisting fistula.

  10. Bilateral prosthetic hip joint infections associated with a Psoas abscess. A Case Report

    PubMed Central

    Gunaratne, G D Rajitha; Khan, Riaz J K; Tan, Cynthia; Golledge, Clayton

    2016-01-01

    Introduction: Psoas abscess is a recognized but under-diagnosed complication of prosthetic hip joint infections. Case report: We report a case of a 68-year-old man with right and left hip arthroplasties performed 22 and 14 years ago, respectively, who presented with non-specific symptoms and was subsequently diagnosed with left psoas abscess on CT scan. Drainage of the psoas abscess was complicated by the formation of a discharging sinus connected to the left hip. He then developed an infected right thigh haematoma, which also formed a discharging sinus connecting to the right hip post-drainage. He was treated with bilateral two-stage revision total hip arthroplasties and multiple courses of prolonged antibacterial therapy. Both abscesses and hip joints cultured the same species of multi-sensitive Staphylococcus aureus. The causal link between the psoas abscess and the prosthetic hip infections is discussed, as well as the investigation and management. Conclusion: We recommend routine exploration of the iliopsoas bursa when revision of an infected total hip arthroplasty is performed to rule out intrapelvic spread of the infection [3]. There should be high index of suspicion of prosthetic hip infection in patients presenting with Psoas abscess and vice versa. A CT scan might be warranted to rule out concomitant infection in both these patients. PMID:28116254

  11. Cerebral abscess after neuro-vascular embolization: Own experience and review of the literature.

    PubMed

    Cossu, G; Daniel, R T; Messerer, M

    2017-03-01

    Cerebral abscesses are a rare complication after therapeutic neuro-endovascular procedures. The aim of this article is to report a case of cerebral abscess after the endovascular embolization of a cerebral aneurysm and to discuss and review all the cases of cerebral abscess secondary to neurovascular embolization described in the literature up to now. A 40-year-old female patient was treated using an endovascular embolization for a ruptured aneurysm of the basilar artery tip. After 2 months she presented with a cerebellar abscess. Antibiotic therapy was started, and a surgical drainage of the collection was performed, with a favorable postoperative outcome. Twelve other cases were reported in the literature, in five cases secondary to the treatment of a cerebral aneurysm, in six cases secondary to a cerebral arterio-venous malformation (AVM) and in one case secondary to a dural arterio-venous fistula (DAVF). The pathophysiology and risk factors of cerebral abscess formation are discussed in detail. The risk of cerebral abscesses after neuro-endovascular embolization is not negligible, and a growing number of patients affected by this complication may be expected in the near future because of the spreading of neuro-endovascular techniques. The role of prophylactic antibiotic therapy in specific subgroups of patients is still debated.

  12. Star formation in M 33: the radial and local relations with the gas

    NASA Astrophysics Data System (ADS)

    Verley, S.; Corbelli, E.; Giovanardi, C.; Hunt, L. K.

    2010-02-01

    Aims: In the Local Group spiral galaxy M 33, we investigate the correlation between the star formation rate (SFR) surface density, Σ_SFR, and the gas density Σ_gas (molecular, atomic, and total). We also explore whether there are other physical quantities, such as the hydrostatic pressure and dust optical depth, which establish a good correlation with Σ_SFR. Methods: We use the Hα, far-ultraviolet (FUV), and bolometric emission maps to infer the SFR locally at different spatial scales, and in radial bins using azimuthally averaged values. Most of the local analysis is done using the highest spatial resolution allowed by gas surveys, 180 pc. The Kennicutt-Schmidt (KS) law, Σ_SFR ∝ Σ_gas^n is analyzed by three statistical methods. Results: At all spatial scales, with Hα emission as a SFR tracer, the KS indices n are always steeper than those derived with the FUV and bolometric emissions. We attribute this to the lack of Hα emission in low luminosity regions where most stars form in small clusters with an incomplete initial mass function at their high mass end. For azimuthally averaged values the depletion timescale for the molecular gas is constant, and the KS index is n_H_2=1.1 ±0.1. Locally, at a spatial resolution of 180 pc, the correlation between Σ_SFR and Σ_gas is generally poor, even though it is tighter with the molecular and total gas than with the atomic gas alone. Considering only positions where the CO J=1-0 line is above the 2-σ detection threshold and taking into account uncertainties in Σ_H_2 and Σ_SFR, we obtain a steeper KS index than obtained with radial averages: n_H_2=2.22 ±0.07 (for FUV and bolometric SFR tracers), flatter than that relative to the total gas (n_Htot=2.59 ±0.05). The gas depletion timescale is therefore larger in regions of lower Σ_SFR. Lower KS indices (n_H_2=1.46 ±0.34 and n_H_2=1.12) are found using different fitting techniques, which do not account for individual position uncertainties. At coarser spatial

  13. Brittleness modelling of shale gas reservoir: Case study of Pematang formation, Central Sumatera basin

    NASA Astrophysics Data System (ADS)

    Haris, A.; Iskandarsyah, Riyanto, A.

    2017-07-01

    The Pematang formation, which is located at Central Sumatera basin become the prospective shale gas reservoir in the Kisaran area. It is shown by a large potential amount of gas and oil in place. However, there is still a lack of information about the shale properties in this field so it becomes a big challenge for developing the shale gas exploration. Based on the core and petrophysical analysis, it is shown that the formation is dominated by shale and some part is laminated by sand layers. There is a significantly large deposit of shale underneath sand layer. This paper aims to perform the brittleness modeling, which is based on the integration of geophysical and geomechanical data. In the application, the brittleness distribution map is used to delineate the brittle zone of the shale reservoir that has potential to be fractured by using an artificial hydraulic fracturing. The brittleness modeling is performed by using Statistic Linear Gaussian Simulation (SLGS) approach based on the 3D seismic data and the well log data. The brittleness map shows that the potential shale reservoir to be fractured, which is indicated by brittleness index greater than 0.5, is distributed in the eastern part and the north-eastern part of the study area at the depth range of 6308 feet to 7432 feet.

  14. The formation of a massive protostar through the disk accretion of gas.

    PubMed

    Chini, Rolf; Hoffmeister, Vera; Kimeswenger, Stefan; Nielbock, Markus; Nürnberger, Dieter; Schmidtobreick, Linda; Sterzik, Michael

    2004-05-13

    The formation of low-mass stars like our Sun can be explained by the gravitational collapse of a molecular cloud fragment into a protostellar core and the subsequent accretion of gas and dust from the surrounding interstellar medium. Theoretical considerations suggest that the radiation pressure from the protostar on the in-falling material may prevent the formation of stars above ten solar masses through this mechanism, although some calculations have claimed that stars up to 40 solar masses can in principle be formed via accretion through a disk. Given this uncertainty and the fact that most massive stars are born in dense clusters, it was suggested that high-mass stars are the result of the runaway merging of intermediate-mass stars. Here we report observations that clearly show a massive star being born from a large rotating accretion disk. The protostar has already assembled about 20 solar masses, and the accretion process is still going on. The gas reservoir of the circumstellar disk contains at least 100 solar masses of additional gas, providing sufficient fuel for substantial further growth of the forming star.

  15. Formation of Gas Pockets in a Boundary Layer Under Turbulent Forcing

    NASA Astrophysics Data System (ADS)

    Pereira, Francisco; Jeon, David; Gharib, Morteza

    2013-11-01

    Our experiments examine the formation of gas pockets in a flat plate boundary layer in water submitted to turbulent forcing. Air micro-bubbles are injected from wall orifices over surfaces with hydrophilic, hydrophobic and super-hydrophobic wetting properties. In this latter case, the surfaces are coated with paints with water repellent characteristics, or covered with vertically aligned carbon nanotubes (CNTs) that are chemically tuned to produce super-hydrophobicity. The turbulence level of the incoming flow is adjusted through meshes and grids. Bubble injection is operated at constant flow rate, and the mechanism of bubble growth and detachment is investigated through high speed recordings. Super-hydrophobicity is found to promote the attachment of discrete gas voids to the wall, with CNTs favoring the formation of a gas layer. Another finding is that the turbulence intensity affects the stability of microbubbles attached to the wall under super-hydrophobic conditions. This work is supported by ONR Grant N00014-11-1-0031.

  16. Feeding cosmic star formation: exploring high-redshift molecular gas with CO intensity mapping

    NASA Astrophysics Data System (ADS)

    Breysse, Patrick C.; Rahman, Mubdi

    2017-06-01

    The study of molecular gas is crucial for understanding star formation, feedback and the broader ecosystem of a galaxy as a whole. However, we have limited understanding of its physics and distribution in all but the nearest galaxies. We present a new technique for studying the composition and distribution of molecular gas in high-redshift galaxies inaccessible to existing methods. Our proposed approach is an extension of carbon monoxide intensity mapping methods, which have garnered significant experimental interest in recent years. These intensity mapping surveys target the 115 GHz 12CO (1-0) line, but also contain emission from the substantially fainter 110 GHz 13CO (1-0) transition. The method leverages the information contained in the 13CO line by cross-correlating pairs of frequency channels in an intensity mapping survey. Since 13CO is emitted from the same medium as the 12CO, but saturates at a much higher column density, this cross-correlation provides valuable information about both the gas density distribution and isotopologue ratio, inaccessible from the 12CO alone. Using a simple model of these molecular emission lines, we show that a future intensity mapping survey can constrain the abundance ratio of these two species and the fraction of emission from optically thick regions to order ˜30 per cent. These measurements cannot be made by traditional CO observations, and consequently the proposed method will provide unique insight into the physics of star formation, feedback and galactic ecology at high redshifts.

  17. Enhanced formation of disinfection byproducts in shale gas wastewater-impacted drinking water supplies.

    PubMed

    Parker, Kimberly M; Zeng, Teng; Harkness, Jennifer; Vengosh, Avner; Mitch, William A

    2014-10-07

    The disposal and leaks of hydraulic fracturing wastewater (HFW) to the environment pose human health risks. Since HFW is typically characterized by elevated salinity, concerns have been raised whether the high bromide and iodide in HFW may promote the formation of disinfection byproducts (DBPs) and alter their speciation to more toxic brominated and iodinated analogues. This study evaluated the minimum volume percentage of two Marcellus Shale and one Fayetteville Shale HFWs diluted by fresh water collected from the Ohio and Allegheny Rivers that would generate and/or alter the formation and speciation of DBPs following chlorination, chloramination, and ozonation treatments of the blended solutions. During chlorination, dilutions as low as 0.01% HFW altered the speciation toward formation of brominated and iodinated trihalomethanes (THMs) and brominated haloacetonitriles (HANs), and dilutions as low as 0.03% increased the overall formation of both compound classes. The increase in bromide concentration associated with 0.01-0.03% contribution of Marcellus HFW (a range of 70-200 μg/L for HFW with bromide = 600 mg/L) mimics the increased bromide levels observed in western Pennsylvanian surface waters following the Marcellus Shale gas production boom. Chloramination reduced HAN and regulated THM formation; however, iodinated trihalomethane formation was observed at lower pH. For municipal wastewater-impacted river water, the presence of 0.1% HFW increased the formation of N-nitrosodimethylamine (NDMA) during chloramination, particularly for the high iodide (54 ppm) Fayetteville Shale HFW. Finally, ozonation of 0.01-0.03% HFW-impacted river water resulted in significant increases in bromate formation. The results suggest that total elimination of HFW discharge and/or installation of halide-specific removal techniques in centralized brine treatment facilities may be a better strategy to mitigate impacts on downstream drinking water treatment plants than altering

  18. Syringe test screening of microbial gas production activity: Cases denitrification and biogas formation.

    PubMed

    Østgaard, Kjetill; Kowarz, Viktoria; Shuai, Wang; Henry, Ingrid A; Sposob, Michal; Haugen, Hildegunn Hegna; Bakke, Rune

    2017-01-01

    Mass produced plastic syringes may be applied as vessels for cheap, simple and large scale batch culture testing. As illustrated for the cases of denitrification and of biogas formation, metabolic activity was monitored by direct reading of the piston movement due to the gas volume formed. Pressure buildup due to friction was shown to be moderate. A piston pull and slide back routine can be applied before recording gas volume to minimize experimental errors due to friction. Inoculum handling and activity may be conveniently standardized as illustrated by applying biofilm carriers. A robust set of positive as well as negative controls ("blanks") should be included to ensure quality of the actual testing. The denitrification test showed saturation response at increasing amounts of inoculum in the form of adapted moving bed biofilm reactor (MBBR) carriers, with well correlated nitrate consumption vs. gas volume formed. As shown, the denitrification test efficiently screened different inocula at standardized substrates. Also, different substrates were successfully screened and compared at standardized inocula. The biogas potential test showed efficient screening of different substrates with effects of relative amounts of carbohydrate, protein, fat. A second case with CO2 capture reclaimer waste as substrate demonstrated successful use of co-feeding to support waste treatment and how temperature effects on kinetics and stoichiometry can be observed. In total, syringe test screening of microbial gas production seems highly efficient at a low cost when properly applied. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Formation of Wide-orbit Gas Giants Near the Stability Limit in Multi-stellar Systems

    NASA Astrophysics Data System (ADS)

    Higuchi, A.; Ida, S.

    2017-09-01

    We have investigated the formation of a circumstellar wide-orbit gas giant planet in a multiple stellar system. We consider a model of orbital circularization for the core of a giant planet after it is scattered from an inner disk region by a more massive planet, which was proposed by Kikuchi et al. We extend their model for single star systems to binary (multiple) star systems, by taking into account tidal truncation of the protoplanetary gas disk by a binary companion. As an example, we consider a wide-orbit gas giant in a hierarchical triple system, HD131399Ab. The best-fit orbit of the planet is that with semimajor axis ˜80 au and eccentricity ˜0.35. As the binary separation is ˜350 au, it is very close to the stability limit, which is puzzling. With the original core location ˜20-30 au, the core (planet) mass ˜50 M E and the disk truncation radius ˜150 au, our model reproduces the best-fit orbit of HD131399Ab. We find that the orbit after the circularization is usually close to the stability limit against the perturbations from the binary companion, because the scattered core accretes gas from the truncated disk. Our conclusion can also be applied to wider or more compact binary systems if the separation is not too large and another planet with ≳20-30 Earth masses that scattered the core existed in inner region of the system.

  20. Formation of Carbamate Anions by the Gas-phase Reaction of Anilide Ions with CO2.

    PubMed

    Liu, Chongming; Nishshanka, Upul; Attygalle, Athula B

    2016-05-01

    The anilide anion (m/z 92) generated directly from aniline, or indirectly as a fragmentation product of deprotonated acetanilide, captures CO2 readily to form the carbamate anion (m/z 136) in the collision cell, when CO2 is used as the collision gas in a tandem-quadrupole mass spectrometer. The gas-phase affinity of the anilide ion to CO2 is significantly higher than that of the phenoxide anion (m/z 93), which adds to CO2 only very sluggishly. Our results suggest that the efficacy of CO2 capture depends on the natural charge density on the nitrogen atom, and relative nucleophilicity of the anilide anion. Generally, conjugate bases generated from aniline derivatives with proton affinities (PA) less than 350 kcal/mol do not tend to add CO2 to form gaseous carbamate ions. For example, the anion generated from p-methoxyaniline (PA = 367 kcal/mol) reacts significantly faster than that obtained from p-nitroaniline (PA = 343 kcal/mol). Although deprotonated p-aminobenzoic acid adds very poorly because the negative charge is now located primarily on the carboxylate group, it reacts more efficiently with CO2 if the carboxyl group is esterified. Moreover, mixture of CO2 and He as the collision gas was found to afford more efficient adduct formation than CO2 alone, or as mixtures made with nitrogen or argon, because helium acts as an effective "cooling" gas and reduces the internal energy of reactant ions.

  1. Evaluation of the geological relationships to gas hydrate formation and stability

    SciTech Connect

    Not Available

    1985-01-01

    During the reported year we have enhanced our knowledge on and gained considerable experience in assessment of the gas hydrate resources in the offshore environments. Specifically, we have learned and gained experience in the following: Efficiently locating data sources, including published literature and unpublished information. We have established personal communication extremely critical in data accessability and acquisition. We have updated information pertinent to gas hydrate knowledge, also based on thorough study and evaluation of most Russian literature and additional publications in languages other than English. Besides critical evaluation of widely spread literature, in many cases our reports include previously unpublished information (e.g. BSRs from the Gulf of Mexico). The assessment of the gas resources potential associated with the gas hydrates, although in most cases at a low level of confidence, appears also very encouraging for further, more detailed, study. We are also confident that, because of the present reports' format, new data and a concept-oriented approach, the result of our study will be of strong interest to various industries, research institutions and numerous governmental agencies.

  2. Armature formation in a railgun using a two-stage light-gas gun injector

    SciTech Connect

    Hawke, R.S.; Susoeff, A.R.; Asay, J.R.; Hall, C.A.; Konrad, C.H.; Hickman, R.J.; Sauve, J.L.

    1989-06-01

    During the past decade several research groups have tried to achieve reliable acceleration of projectiles to velocities in excess of 8 km/s by using a railgun. All attempts have met with difficulties. However, in the past four years the researchers have come to agree on the nature and causes of the difficulties. The consensus is that the hot plasma armature - used to commutate across the rails and to accelerate the projectile - causes ablation of the barrel wall; this ablation ultimately results in parasitic secondary arc formation through armature separation and/or restrike. The subsequence deprivation of current to the propulsion armature results in a limit to the achievable projectile velocity. Methods of mitigating the process are under study. One method uses a two-stage light-gas gun as a preaccelerator/injector to the railgun. The gas gun serves a double purpose: It quickly accelerates the projectile to a high velocity, and it fills the barrel behind the propulsive armature with insulating gas. While this approach is expected to improve railgun performance, it also requires development of techniques to form the propulsive armature behind the projectile in the high-velocity, high-pressure gas stream. This paper briefly summarizes the problems encountered in attempts to achieve hypervelocities with a railgun. Included is a description of the phenomenology and details of joint Sandia National Laboratories, Albuquerque/Lawrence Livermore National Laboratory (SNLA/LNLL) work at SNLA on a method for forming the needed plasma armature.

  3. Formation of Carbamate Anions by the Gas-phase Reaction of Anilide Ions with CO2

    NASA Astrophysics Data System (ADS)

    Liu, Chongming; Nishshanka, Upul; Attygalle, Athula B.

    2016-05-01

    The anilide anion ( m/z 92) generated directly from aniline, or indirectly as a fragmentation product of deprotonated acetanilide, captures CO2 readily to form the carbamate anion ( m/z 136) in the collision cell, when CO2 is used as the collision gas in a tandem-quadrupole mass spectrometer. The gas-phase affinity of the anilide ion to CO2 is significantly higher than that of the phenoxide anion ( m/z 93), which adds to CO2 only very sluggishly. Our results suggest that the efficacy of CO2 capture depends on the natural charge density on the nitrogen atom, and relative nucleophilicity of the anilide anion. Generally, conjugate bases generated from aniline derivatives with proton affinities (PA) less than 350 kcal/mol do not tend to add CO2 to form gaseous carbamate ions. For example, the anion generated from p-methoxyaniline (PA = 367 kcal/mol) reacts significantly faster than that obtained from p-nitroaniline (PA = 343 kcal/mol). Although deprotonated p-aminobenzoic acid adds very poorly because the negative charge is now located primarily on the carboxylate group, it reacts more efficiently with CO2 if the carboxyl group is esterified. Moreover, mixture of CO2 and He as the collision gas was found to afford more efficient adduct formation than CO2 alone, or as mixtures made with nitrogen or argon, because helium acts as an effective "cooling" gas and reduces the internal energy of reactant ions.

  4. Ionized gas pressure correlates with star formation intensity in nearby starbursts

    NASA Astrophysics Data System (ADS)

    Jiang, Tianxing; Malhotra, Sangeeta; Yang, Huan

    2016-06-01

    We estimate the electron density of the ionized gas and thus the thermal pressure in HII regions; and compare that to the SFR (star formation rate) surface density for a combined sample of about 40 green peas and Lyman Break Analogs at z < 0.30. The electron density of the ionized gas is measured from sulfur line ratio ([SII] 6716 / 6731). We find that the SFR surface density is correlated with the electron density and the thermal pressure in HII regions for the star-forming galaxies with SFR surface density above a certain threshold. This work shows quantitatively the correlation between SFR surface density and electron density and that between SFR surface density and the thermal pressure in HII regions for the nearby starburst galaxies. This is consistent with theoretical models of disks (e.g. Kim et al. (2011) if we assume that the thermal pressure in HII regions is comparable to the total diffuse gas pressure at the midplane of the diffuse neutral gas. It is also in agreement with the results from star-forming galaxies at z ~ 2.5. We might infer that the starburst galaxies at low-redshift (z < 0.3) share similar physical properties to the galaxies at high redshift (z ~ 2.5).

  5. Doppler indices of gas phase formation in hypobaric environments: Time-intensity analysis

    NASA Technical Reports Server (NTRS)

    Powell, Michael R.

    1991-01-01

    A semi-quantitative method to analyze decompression data is described. It possesses the advantage that it allows a graded response to decompression rather than the dichotomous response generally employed. A generalized critical volume (C-V), or stoichiometric time-dependent equilibrium model is examined that relates the constant of the equation P sub i equals m P sub f plus b to variable tissue supersaturation and gas washout terms. The effects of the tissue ratio on gas phase formation indicate that a decreased ratio yields fewer individuals with Doppler detectable gas bubbles, but those individuals still present with Spencer Grade 3 or 4. This might indicate a local collapse of tissue saturation. The individuals with Grade 3 or 4 could be at risk for type 2 decompression sickness by transpulmonic arterialization. The primary regulator of the problems of decompression sickness is the reduction of local supersaturation, presumably governed by the presence and number of gas micronuclei. It is postulated that a reduction in these nuclei will favor a low incidence of decompression sickness in microgravity secondary to hypokinesia and adynamia.

  6. Connecting the Dense Gas and Young Stars in the CARMA Large Area Star Formation Survey

    NASA Astrophysics Data System (ADS)

    Mundy, Lee G.; Storm, Shaye; Looney, Leslie; Lee, Katherine I.; Fernandez Lopez, Manuel; Ostriker, Eve C.; Chen, Che-Yu; CLASSy Team

    2016-01-01

    The CARMA Large Area Star Formation Survey (CLASSy) imaged the dense gas structure and kinematics in five, roughly 1 pc scale regions in the Serpens and Perseus clouds with 7" angular resolution. The spatial distribution and Class of the young stellar population (YSOs) is available for these regions from the Spitzer c2d and Gould Belt surveys, with added sources from the Herschel 70 micron images. Together, these datasets allow us to compare, for the first time at similar spatial resolutions, the distributions of the dense gas and YSOs over regions containing up to 90 identified YSOs. This enables a detailed look at the separation between YSOs and the nearest dense gas peak and a measure of overall relationship between the YSO and dense gas distributions. We find that most Class 0 YSOs are forming in the highest column density regions: leaves in the dendrogram analysis utilized by CLASSy. In Serpens and Perseus, we find that 29% and 38%, respectively, of the leaves have identified embedded YSOs. Class 1 sources are less confined to leaf locations; Class II sources are distributed throughout regions, mostly away from hierarchical peaks. This trend could be due to a modest (0.1 km/sec) velocity difference between YSOs and their natal cores, or due to the YSOs consuming or dispersing their natal cores.

  7. Secondary Organic Aerosol formation from the gas-phase reaction of catechol with ozone

    NASA Astrophysics Data System (ADS)

    Coeur-Tourneur, C.; Tomas, A.; Guilloteau, A.; Henry, F.; Ledoux, F.; Visez, N.; Riffault, V.; Wenger, J. C.; Bedjanian, Y.; Foulon, V.

    2009-04-01

    The formation of secondary organic aerosol from the gas-phase reaction of catechol (1,2-dihydroxybenzene) with ozone has been studied in two smog chambers (at the LPCA in France and at the CRAC in Ireland). Aerosol production was monitored using a scanning mobility particle sizer. The overall organic aerosol yield (Y) was determined as the ratio of the suspended aerosol mass corrected for wall losses (Mo) to the total reacted catechol concentrations, assuming a particle density of 1.4 g cm-3. Analysis of the data clearly shows that Y is a strong function of Mo and that secondary organic aerosol formation can be expressed by a one-product gas/particle partitioning absorption model. The aerosol formation is affected by the initial catechol concentration, which leads to aerosol yields ranging from 17% to 86%. The aerosol yields determined in the LPCA and CRAC smog chambers were comparable and were also in accordance with those determined in a previous study performed in EUPHORE (EUropean PHOto REactor, Spain).

  8. Formation of TiC-core, Graphitic-mantle Grains from CO Gas

    NASA Technical Reports Server (NTRS)

    Kimura, Yuki; Nuth, Joseph A., III; Ferguson, Frank T.

    2005-01-01

    We demonstrate a new formation route for TiC-core, graphitic-mantle spherules that does not require c-atom addition and the very long timescales associated with such growth (Bernatowicz et al. 1996). Carbonaceous materials can also be formed from C2H2 and its derivatives, as well as from CO gas. In this paper, we will demonstrate that large cage structure carbon particles can be produced from CO gas by the Boudouard reaction. Since the sublimation temperature for such fullerenes is low, the large cages can be deposited onto previously-nucleated TiC and produce TiC-core, graphitic-mantle spherules. New constraints for the formation conditions and the timescale for the formation of TiC-core, graphitic-mantle spherules are suggested by the results of this study. In particular, TiC-core, graphitic-mantle grains found in primitive meteorites that have never experienced hydration could be mantled by fullerenes or carbon nanotubes rather than by graphite. In situ observations of these grains in primitive anhydrous meteoritic matrix could confirm or refute this prediction and would demonstrate that the graphitic mantle on such grains is a metamorphic feature due to interaction of the pre-solar fullerenes with water within the meteorite matrix.

  9. Pion-pair formation and the pion dispersion relation in a hot pion gas

    NASA Astrophysics Data System (ADS)

    Alm, T.; Chanfray, G.; Schuck, P.; Welke, G.

    1997-02-01

    The possibility of pion-pair formation in a hot pion gas, based on the bosonic gap equation, is pointed out and discussed in detail. The critical temperature for condensation of pion pairs (Evans-Rashid transition) is determined as a function of the pion density. As for fermions, this phase transition is signated by the appearance of a pole in the two-particle propagator. In Bose systems there exists a second, lower critical temperature, associated with the appearance of the single-particle condensate. Between the two critical temperatures the pion dispersion relation changes from the usual quasiparticle dispersion to a Bogoliubov-like dispersion relation at low momenta. This generalizes the non-relativistic result for an attractive Bose gas by Evans et al. Possible consequences for the inclusive pion spectra measured in heavy-ion collisions at ultra-relativistic energies are discussed.

  10. Probing Toluene and Ethylbenzene Stable Glass Formation using Inert Gas Permeation

    SciTech Connect

    Smith, R. Scott; May, Robert A.; Kay, Bruce D.

    2015-09-01

    Inert gas permeation is used to investigate the formation of stable glasses of toluene and ethylbenzene. The effect of deposition temperature (Tdep) on the kinetic stability of the vapor deposited glasses is determined using Kr desorption spectra from within sandwich layers of either toluene or ethylbenzene. The results for toluene show that the most stable glass is formed at Tdep = 0.92 Tg, although glasses with a kinetic stability within 50% of the most stable glass were found with deposition temperatures from 0.85 to 0.95 Tg. Similar results were found for ethylbenzene, which formed its most stable glass at 0.91 Tg and formed stable glasses from 0.81 to 0.96 Tg. These results are consistent with recent calorimetric studies and demonstrate that the inert gas permeation technique provides a direct method to observe the onset of molecular translation motion that accompanies the glass to supercooled liquid transition.

  11. Gas-phase products and secondary organic aerosol formation from the ozonolysis and photooxidation of myrcene

    NASA Astrophysics Data System (ADS)

    Böge, Olaf; Mutzel, Anke; Iinuma, Yoshiteru; Yli-Pirilä, Pasi; Kahnt, Ariane; Joutsensaari, Jorma; Herrmann, Hartmut

    2013-04-01

    Terrestrial vegetation releases a great variety of volatile organic compounds (VOC) into the atmosphere. Monoterpenes, like myrcene, contribute significantly to this global biogenic VOC emission. In the atmosphere, monoterpenes rapidly undergo oxidation reactions by OH radicals (mainly during the daytime), NO3 radicals (mainly during the nighttime) and O3 to form multifunctional oxidation products. The products of these reactions are likely to be of low volatility and hence might lead to secondary organic aerosol (SOA) formation. In the present study, we report results from a series of chamber experiments performed in the LEAK chamber at TROPOS in which the gas-phase products and SOA yields obtained from myrcene O3 reactions with and without an OH radical scavenger as well as from the myrcene OH radical reaction in the presence of NOx have been measured. During the experiments the consumption of myrcene as well as the formation of gas-phase products was monitored using a proton transfer reaction mass spectrometer (PTR-MS). Ozone concentration was measured by an O3 monitor and the mixing ratios of nitrogen oxides were measured by a NOx monitor. Particle size distributions between 3-900 nm were monitored every 11 min using a differential mobility particle sizer (DMPS) system. In addition to the products observed by means of the PTR-MS by their m/z values, an identification of carbonylic compounds by their DNPH derivatives was performed. Beside low molecular mass products the formation of 4-vinyl-4-pentenal with a yield of 55 % in myrcene ozonolysis has been observed. The further oxidation of this major first generation product lead to the formation of two dicarbonylic products with m/z 113 and to SOA formation. The influence of the continuing oxidation of 4-vinyl-4-pentenal on SOA formation will be discussed in detail. The emergence of the gas-phase product hydroxyacetone as direct result of the myrcene ozone reaction will be mooted, because hydroxyacetone seems to

  12. Association of gas hydrate formation in fluid discharges with anomalous hydrochemical profiles

    NASA Astrophysics Data System (ADS)

    Matveeva, T.

    2009-04-01

    Numerous investigations worldwide have shown that active underwater fluid discharge produces specific structures on the seafloor such as submarine seepages, vents, pockmarks, and collapse depressions. Intensive fluxes of fluids, especially of those containing hydrocarbon gases, result in specific geochemical and physical conditions favorable for gas hydrate (GH) formation. GH accumulations associated with fluid discharge are usually controlled by fluid conduits such as mud volcanoes, diapirs or faults. During last decade, subaqueous GHs become the subject of the fuel in the nearest future. However, the expediency of their commercial development can be proved solely by revealing conditions and mechanisms of GH formation. Kinetic of GH growth (although it is incompletely understood) is one of the important parameters controlling their formation among with gas solubility, pressure, temperature, gas quantity and others. Original large dataset on hydrate-related interstitial fluids obtained from different fluid discharge areas at the Sea of Okhotsk, Black Sea, Gulf of Cadiz, Lake Baikal (Eastern Siberia) allow to suggest close relation of the subaqueous GH formation process to anomalous hydrochemical profiles. We have studied the chemical and isotopic composition of interstitial fluids from GH-bearing and GH-free sediments obtained at different GH accumulations. Most attention was paid to possible influence of the interstitial fluid chemistry on the kinetic of GH formation in a porous media. The influence of salts on methane solubility within hydrate stability zones was considered by Handa (1990), Zatsepina & Buffet (1998), and later by Davie et al. (2004) from a theoretical point of view. Our idea is based on the experimentally proved fact that fugacity coefficient of methane dissolved in saline gas-saturated water which is in equilibrium with hydrates, is higher than that in more fresh water though the solubility is lower. Therefore, if a gradient of water salinity

  13. The Key Roles of the Gas Disk in the Formation and Evolution of Planetary Systems

    NASA Astrophysics Data System (ADS)

    Liu, H. G.

    2012-11-01

    The detection of exoplanets becomes hotter and hotter, especially the detection of Earth-like exoplanets. With the accumulation of observational data and the progress of Kepler mission of NASA, more exoplanets can be found or confirmed. The understanding of formation and evolution of exoplanets will be largely improved when much more samples are provided. According to the acknowledged theories of planet formation, the protoplanet is formed in the protoplanetary disc. Due to the interactions between the disc and protoplanets, the property of the disc plays a key role during the formation and evolution of planets. We investigate the later stage of planet formation, when the Mars-sized cores appear and the gas disc has not been depleted yet. Interactions among the planetary cores can excite their orbital eccentricities, accelerate their mergings, and thus sculpture their final orbital architecture. The interactions between the cores and gas discs lead to the type I and II migrations as well as the eccentricity damping. However, the rates of type I, II migrations are still uncertain in different disc models. In chapter 1, we introduce the main methods of exoplanet detection and the achievements of Kepler space telescope. We also list some examples of exoplanetary systems to show their diversity. The acknowledged theories of planet formation, including the gravitational instability and core accretion scenarios, are presented in detail in chapter 2. The studies in chapter 3 contribute to the final assembling of planetary systems with N-body simulations, including the type I and II migrations of planets, the eccentricity damping, and the gas accretion of massive cores in a viscous disk. In order to compare the observations in statistics, we use the Monte Carlo method to set a distribution of different discs. Our results of simulations interpret the distribution of exoplanets and may be a guidance for the further observations. In chapter 5, considering the uncertainty of

  14. Characterization of Gas Hydrates Formation and Dissociation Using Thermal Analysis and Calorimetry

    NASA Astrophysics Data System (ADS)

    Rudow, M.; Lilova, K.

    2015-12-01

    In general, the gas hydrates are formed at low temperature and high pressure which requires a special technique to mimic the natural conditions. The hydrate thermal properties: heat capacity, heat of dissociation, are crucial for evaluating the effects on climate change and for a prediction of the gas production rates from hydrate reservoirs. The effect of the porous materials on the dissociation of synthetic methane hydrates was investigated at 150 - 300 K and atmospheric pressure. Another experiment with methane hydrates, but at high pressure (20 MPa) was performed at near room temperature using a highly sensitive micro-differential scanning calorimeter with a specifically design high pressure vessel (the vessel can withstand a pressure up to 1000 bars). The thermal cycle for measuring the methane hydrate dissociation in water includes cooling down a water solution under a certain methane pressure (30 to 350 bars) to -30 C to allow water crystallization and hydrate formation, then heated up to room temperature. The endothermic peak, following the ice melting is associated to the hydrate dissociation process and gives the enthalpy of the hydrate decomposition. The kinetics of the hydrates formation could also be predicted by a rapid DSC cooling experiment followed by isothermal step and heating. Both dissociation and specific heats of synthetic methane and ethane hydrates were measured under high-pressure condition by using a heat-flow type calorimeter to understand thermodynamic properties of gas hydrates under submarine/sublacustrine environments. The large reserves of natural gas are present as clathrate hydrates in permafrost regions and beneath the oceans have generated interest in the study of their thermophysical properties such as heat capacity and thermal conductivity. The effect of isotopic substitution in both THF and water on the eutectic and hydrate melting temperatures in water-tetrahydrofuran systems studied by DSC will be shown as an example.

  15. CARMA Large Area Star Formation Survey: Dense Gas in the Young L1451 Region of Perseus

    NASA Astrophysics Data System (ADS)

    Storm, Shaye; Mundy, Lee G.; Lee, Katherine I.; Fernández-López, Manuel; Looney, Leslie W.; Teuben, Peter; Arce, Héctor G.; Rosolowsky, Erik W.; Meisner, Aaron M.; Isella, Andrea; Kauffmann, Jens; Shirley, Yancy L.; Kwon, Woojin; Plunkett, Adele L.; Pound, Marc W.; Segura-Cox, Dominique M.; Tassis, Konstantinos; Tobin, John J.; Volgenau, Nikolaus H.; Crutcher, Richard M.; Testi, Leonardo

    2016-10-01

    We present a 3 mm spectral line and continuum survey of L1451 in the Perseus Molecular Cloud. These observations are from the CARMA Large Area Star Formation Survey (CLASSy), which also imaged Barnard 1, NGC 1333, Serpens Main, and Serpens South. L1451 is the survey region with the lowest level of star formation activity—it contains no confirmed protostars. HCO+, HCN, and N2H+ (J=1\\to 0) are all detected throughout the region, with HCO+ being the most spatially widespread, and molecular emission seen toward 90% of the area above N(H2) column densities of 1.9 × 1021 cm-2. HCO+ has the broadest velocity dispersion, near 0.3 km s-1 on average, compared with ˜0.15 km s-1 for the other molecules, thus representing a range of subsonic to supersonic gas motions. Our non-binary dendrogram analysis reveals that the dense gas traced by each molecule has a similar hierarchical structure, and that gas surrounding the candidate first hydrostatic core (FHSC), L1451-mm, and other previously detected single-dish continuum clumps has similar hierarchical structure; this suggests that different subregions of L1451 are fragmenting on the pathway to forming young stars. We determined that the three-dimensional morphology of the largest detectable dense-gas structures was relatively ellipsoidal compared with other CLASSy regions, which appeared more flattened at the largest scales. A virial analysis shows that the most centrally condensed dust structures are likely unstable against collapse. Additionally, we identify a new spherical, centrally condensed N2H+ feature that could be a new FHSC candidate. The overall results suggest that L1451 is a young region starting to form its generation of stars within turbulent, hierarchical structures.

  16. The Gas Phase Mass Metallicity Relation for Dwarf Galaxies: Dependence on Star Formation Rate and H I Gas Mass

    NASA Astrophysics Data System (ADS)

    Jimmy; Tran, Kim-Vy; Saintonge, Amélie; Accurso, Gioacchino; Brough, Sarah; Oliva-Altamirano, Paola

    2015-10-01

    Using a sample of dwarf galaxies observed using the VIMOS IFU on the Very Large Telescope, we investigate the mass-metallicity relation (MZR) as a function of star formation rate (FMRSFR) as well as HI-gas mass (FMRHI). We combine our IFU data with a subsample of galaxies from the ALFALFA HI survey crossmatched to the Sloan Digital Sky Survey (SDSS) to study the FMRSFR and FMRHI across the stellar mass range 106.6-108.8 M⊙, with metallicities as low as 12 + log(O/H) = 7.67. We find the 1σ mean scatter in the MZR to be 0.05 dex. The 1σ mean scatter in the FMRSFR (0.02 dex) is significantly lower than that of the MZR. The FMRSFR is not consistent between the IFU observed galaxies and the ALFALFA/SDSS galaxies for SFRs lower than 10-2.4 M⊙ yr-1, however, this could be the result of limitations of our measurements in that regime. The lowest mean scatter (0.01 dex) is found in the FMRHI. We also find that the FMRHI is consistent between the IFU observed dwarf galaxies and the ALFALFA/SDSS crossmatched sample. We introduce the fundamental metallicity luminosity counterpart to the FMR, again characterized in terms of SFR (FMLSFR) and HI-gas mass (FMLHI). We find that the FMLHI relation is consistent between the IFU observed dwarf galaxy sample and the larger ALFALFA/SDSS sample. However, the 1σ scatter for the FMLHI relation is not improved over the FMRHI scenario. This leads us to conclude that the FMRHI is the best candidate for a physically motivated fundamental metallicity relation. Based on VLT service mode observations (Programs 081.B-0649 and 083.B-0662) gathered at the European Southern Observatory, Chile.

  17. Giant Thyroid Abscess Related to Postpartum Brucella Infection

    PubMed Central

    Akdemir, Zülküf; Karaman, Erbil; Akdeniz, Hüseyin; Alptekin, Cem

    2015-01-01

    Thyroid gland infection, although rare, may be a life threatening disease. Thyroid abscess, arising from acute suppurative thyroiditis (AST), is a rare clinic condition depending on widespread use of antibiotics. Infection may involve one or both lobes and abscess formation may not be apparent until late stage of the progress of illness. Thyroid left lobe is more often affected than the right one. Brucellosis, especially obvious in endemic areas, is a widely seen zoonosis around the world. Although brucella infection can affect many organs through various complications, thyroid gland infection is rare. We aimed to present ultrasonography (USG) and magnetic resonance images (MRI) of a case with an acute thyroiditis which rapidly developed and grew fast on the left half of the neck during the first postpartum month. As far as we know from literature reviewing, our case is the first case report of a thyroid abscess arising from brucella infection which is developed in first postpartum period with images of ultrasonography and MRI. PMID:25861492

  18. Intensification of hydrate formation by means of explosive boiling incipience of rarefied gas in a bulk of water

    NASA Astrophysics Data System (ADS)

    Mezentsev, I. V.; Meleshkin, A. V.; Elistratov, D. S.; Elistratov, S. L.; Mutali, M. N.

    2016-10-01

    The experiments on obtaining gas hydrate of refrigerant 134a were carried out by the method, based on explosive boiling-up of a layer of liquefied gas in a bulk of water at decompression. It is shown that this method combines several factors, leading to intensification of hydrate formation process, resulting in the fast gas hydrate growth. The effect of the decompression rate on the volume of produced hydrate was studied experimentally.

  19. Assessment of undiscovered continuous oil and gas resources in the Monterey Formation, Los Angeles Basin Province, California, 2015

    USGS Publications Warehouse

    Tennyson, Marilyn E.; Charpentier, Ronald R.; Klett, Timothy R.; Brownfield, Michael E.; Pitman, Janet K.; Gaswirth, Stephanie B.; Hawkins, Sarah J.; Le, Phuong A.; Lillis, Paul G.; Marra, Kristen R.; Mercier, Tracey J.; Leathers-Miller, Heidi M.; Schenk, Christopher J.

    2016-07-08

    Using a geology-based assessment methodology, the U.S. Geological Survey assessed technically recoverable mean resources of 13 million barrels of oil, 22 billion cubic feet of gas, and 1 million barrels of natural gas liquids in the Monterey Formation of the Los Angeles Basin Province, California.

  20. Ruptured hepatic abscess mimicking perforated viscus.

    PubMed

    Lai, Yen-Chun; Su, Yu-Jang; Chang, Wen-Han

    2008-11-01

    In the majority of pneumoperitoneum cases we diagnose perforated viscus. We present herein a case of ruptured hepatic abscess mimicking perforated viscus. A 40-year-old man presented to the emergency room with fever and right upper quadrant abdominal pain. The fever had been on/off for a period of 1 month. On physical examination, diffuse abdominal pain with rebounding tenderness was noted. Blood tests showed leukocytosis with left shift, hyperglycemia, and elevated liver function tests. A chest X-ray showed a subdiaphragmatic region air-fluid level, indicating a hepatic abscess. Pneumoperitoneum was also seen. Owing to the status of peritonitis, computed tomography (CT) of the abdomen was performed and revealed an air-containing liver abscess in the right lobe of the liver. Perforation of a hollow organ was also suspected because of the pneumoperitoneum. An emergent laparotomy was immediately performed for the suspicion of a hollow organ perforation. No perforation of the hollow viscus was found. The ruptured hepatic abscess was attributed to the pneumoperitoneum. A blood culture grew Klebsiella pneumoniae four days later, and the same organism was also found in a surgical specimen culture of the abscess. For a ruptured hepatic abscess, surgical intervention with draining of the abscess and cleaning of the abdominal cavity are essential to save patient lives.