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Sample records for laser enucleation vapoenucleation

  1. Are Histological Findings of Thulium Laser Vapo-Enucleation Versus Transurethral Resection of the Prostate Comparable?

    PubMed

    Carmignani, Luca; Macchi, Alberto; Ratti, Dario; Finkelberg, Elisabetta; Casellato, Stefano; Bozzini, Giorgio; Maruccia, Serena; Marenghi, Carlo; Picozzi, Stefano

    2015-09-01

    We investigated if an adequate histological diagnosis can be made from tissue after Thulium laser vapo-enucleation of the prostate (ThuVEP) and whether it is comparable to transurethral prostate resection (TURP) tissue findings in patients with symptomatic benign prostatic hyperplasia. We analyzed 350 ThuLEP and 100 matched TURP tissue specimens from patients who underwent one of the two procedures between January 2009 and June 2014. Thulium Laser Enucleation of Prostate (ThuVEP) was combined with mechanical morcellation of the resected lobe. Each histological specimen was reviewed by two pathologists. Preoperative prostate ultrasound volume, total serum prostatic specific antigen and postoperative tissue weight were evaluated. Microscopic histological diagnosis was assessed by standard histological techniques and immunohistochemical evaluation. Patients were comparable in terms of age and preoperative total serum prostate specific antigen. Incidental adenocarcinoma and high grade PIN of the prostate were diagnosed in a comparable percent of specimens in the 2 groups (2.5 % in the ThuVEP group versus 3 % in the TURP group). Tissue thermal artifacts induced by the Thulium laser are mostly due to coagulation as that of the conventional monopolar diathermy in TURP. Tissue quality was maintained in the ThuVEP histological specimens. Tissue maintain histological characteristics and proprieties without modification for successive immunoistochemical analysis. The pathologist ability to detect incidental prostate cancer and PIN was maintained even if there is a quoted of vaporized tissue.

  2. Efficacy and Safety of 120-W Thulium:Yttrium-Aluminum-Garnet Vapoenucleation of Prostates Compared with Holmium Laser Enucleation of Prostates for Benign Prostatic Hyperplasia

    PubMed Central

    Hong, Kai; Liu, Yu-Qing; Lu, Jian; Xiao, Chun-Lei; Huang, Yi; Ma, Lu-Lin

    2015-01-01

    Background: This study compared the efficacy and safety between 120-W thulium:yttrium-aluminum-garnet (Tm:YAG) vapoenucleation of prostates (ThuVEP) and holmium laser enucleation of prostates (HoLEP) for patients with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). Methods: A retrospective analysis of 88 consecutive patients with symptomatic BPH was carried out, who underwent either 120-W ThuVEP or HoLEP nonrandomly. Patient demographics and peri-operative and 12-month follow-up data were analyzed with the International Prostate Symptom Score (IPSS), quality of life (QoL) score, maximum flow rate (Qmax), postvoid residual urine volume (PVR), and rates of peri-operative and late complications. Results: The patients in each group showed no significant difference in preoperative parameters. Compared with the HoLEP group, patients in the 120-W ThuVEP group required significantly shorter time for laser enucleation (58.3 ± 12.8 min vs. 70.5 ± 22.3 min, P = 0.003), and resulted in a significant superiority in laser efficiency (resected prostate weight/laser enucleation time) for 120-W Tm:YAG laser compared to holmium:YAG laser (0.69 ± 0.18 vs. 0.61 ± 0.19, P = 0.048). During 1, 6, and 12 months of follow-ups, the procedures did not demonstrate a significant difference in IPSS, QoL score, Qmax, or PVR (P > 0.05). Mean peri-operative decrease of hemoglobin in the HoLEP group was similar to the ThuVEP group (17.1 ± 12.0 g/L vs. 15.2 ± 10.1 g/L, P = 0.415). Early and late incidences of complications were low and did not differ significantly between the two groups of 120-W ThuVEP and HoLEP patients (P > 0.05). Conclusions: 120-W ThuVEP and HoLEP are potent, safe and efficient modalities of minimally invasive surgeries for patients with LUTS due to BPH. Compared with HoLEP, 120-W ThuVEP offers advantages of reduction of laser enucleation time and improvement of laser efficiency. PMID:25836607

  3. Thulium:YAG VapoEnucleation of the prostate in large glands: a prospective comparison using 70- and 120-W 2-µm lasers.

    PubMed

    Netsch, Christopher; Bach, Thorsten; Herrmann, Thomas R W; Gross, Andreas J

    2012-03-01

    This study compared the efficacy of 70- and 120-w 2-µm thulium:YAG VapoEnucleation of the prostate (ThuVEP) for patients with benign prostatic obstruction (BPO). A prospective analysis of 84 patients with symptomatic BPO and prostatic enlargement (≥60 ml) who underwent either 70-w (n=44) or 120-w ThuVEP (n=40) non-randomly was carried out. Patient demographics and perioperative and 12-month follow-up data were analysed. The mean prostate volume was 79.90±27.49 ml in patients who had received 70-w ThuVEP, which was less than in those who had received 120-w ThuVEP (88.53±25.10; P=0.033). The mean enucleation (resected weight/laser time, 2.16±1.21 g min(-1) vs. 1.23±0.60 g min(-1); P=0.013), operation efficiency (resected weight/total operation time, 0.76±0.35 g min(-1) vs. 0.42±0.27 g min(-1); P=0.000) and percentage of resected tissue (66.93%±22.79% vs. 45.41%±23.33%; P=0.000) were higher with 120-w treatment compared to 70-w ThuVEP. One patient (1.2% of total patients) (in the 120-w group) required a blood transfusion postoperatively. Sixty-one patients (73%) were available for review at the 12-month follow-up time point. The quality of life (QoL), International Prostate Symptom Score (IPSS), maximum urinary flow rate (Q(max)), postvoiding residual urine (PVR) and prostate volume improved significantly after treatment (P≤0.035) and were not significantly different between those treated with the different devices (70- and 120-w). The median prostate volume reduction was 81.70% and 82.19% with 70- and 120-w ThuVEP, respectively. The incidence of complications was low and did not differ between groups treated with the different devices. Two patients (2.4%) (one per group) had a bladder neck contracture at the follow-up. ThuVEP is a safe and efficacious procedure for the treatment of symptomatic BPO. The incidence of complications was low with both devices. The 120-w thulium:YAG device enhances the effectiveness of ThuVEP with regard to the percentage of

  4. Outcomes following Thulium vapoenucleation of large prostates

    PubMed Central

    Pearce, Shane M.; Pariser, Joseph J.; Malik, Rena D.; Famakinwa, Olufenwa J.; Chung, Doreen E.

    2016-01-01

    ABSTRACT Introduction: Thulium laser VapoEnucleation of the prostate (ThuVEP) is an evolving surgical technique for BPH. Most studies have focused on outcomes in small to medium sized prostates and have originated from Europe and Asia. We sought to describe our experience with ThuVEP for very large prostates in a North American cohort. Materials and Methods: From December 2010 to October 2014, 25 men underwent ThuVEP using the CyberTM® (Quantastem, Italy) thulium laser, all with prostate volume >75mL. Data collected included patient demographics, comorbidities, intraoperative parameters, complications, and post-operative outcomes including maximum flow rate (Qmax), post-void residual (PVR), International Prostate Symptom Score (IPSS), and quality of life score (QoL) in one year of follow-up. Statistical analysis was done using Wilcoxon signed-rank test. Results: At baseline, mean age was 70±9 years and prostate size was 163±62g. Most patients (84%) were in retention and 10 (40%) patients were on anticoagulation. Seven (28%) patients went home the day of surgery (mean hospital stay: 1.2±1.2d). There were 2 intraoperative complications (8%), both cystotomies related to morcellation. Nine patients (36%) experienced a complication, all within 30 days. There were no Clavien ≥III complications. Significant improvements were seen in Qmax, PVR, IPSS, and QoL score at each time interval to 12-months following surgery (all p<0.05). Of 21 patients initially in retention, all were voiding at last follow-up. Conclusions: Our findings suggest that ThuVEP is an effective treatment for BPH in patients with large prostates with sustained results for one year. PMID:27564287

  5. Enucleation is enucleation is enucleation is enucleation.

    PubMed

    Herrmann, Thomas R W

    2016-10-01

    The latest update of the EAU Guidelines on Management of Non-Neurogenic Male Lower Urinary Tract Symptoms, incl. Benign Prostatic Obstruction in 2016 announced a novel acronym for transurethral Endoscopic Enucleation of the Prostate (EEP). This was inspired by a meta-analysis on randomized controlled trials on Holmium Laser Enucleation of the Prostate (HolEP) and bipolar enucleation versus open simple prostatectomy. EEP codes for the common ground of both techniques: "anatomical enucleation." Although study quality with regard to the availability of long-term randomized controlled trials is at the moment mostly available for HoLEP, and bipolar enucleation, the existing data of all other enucleating techniques that have been demonstrated to perform anatomical enucleation as well should also been summarized under the same term. This editorial is a call for embracing this acronym of EEP for all anatomical enucleating techniques in order to serve for the transition from the age of TURP and open prostatectomy toward the age of EEP.

  6. Carbon dioxide laser enucleation of polypoid vocal cords.

    PubMed

    Yates, A; Dedo, H H

    1984-06-01

    Polypoid vocal cords have routinely been treated by endoscopic vocal cord stripping, often-times resulting in prolonged hoarseness postoperatively. Submucosal CO2 laser enucleation of the polypoid tissue, with preservation of a mucosal flap on the medial edge of the cord, has proved to be a valuable improvement. The surgical procedure is described and results are presented which suggest that voice quality is better earlier than is the case after vocal cord stripping.

  7. Holmium laser enucleation of the prostate: patient selection and perspectives

    PubMed Central

    Marien, Tracy; Kadihasanoglu, Mustafa; Miller, Nicole L

    2016-01-01

    Background Multiple endoscopic surgical options exist to treat benign prostatic hyperplasia (BPH), including holmium laser enucleation of the prostate (HoLEP). HoLEP alleviates obstructive prostatic tissue via enucleation, both bluntly with a resectoscope and by cutting tissue with the holmium laser, and removal of adenoma via morcellation. This article reviews patient selection for HoLEP in order to optimize outcomes, costs, and patient satisfaction. Methods A literature review of all studies on HoLEP was conducted. Studies that focused on outcomes in regard to patient and procedural factors were closely reviewed and discussed. Results Various studies found that men with large or small prostates, on antithrombotic therapy, in urinary retention, with bladder hypocontractility, with prostate cancer, undergoing retreatment for BPH, or in need of concomitant surgery for bladder stones and other pathologies do well with HoLEP, as demonstrated by excellent functional and symptomatic outcomes as well as low complication rates. There is a 74–78% rate of retrograde ejaculation following HoLEP. Techniques to preserve ejaculatory function following enucleative techniques have not been able to demonstrate a significant improvement. Conclusion Patient selection for HoLEP can include most men with bothersome BPH who have evidence of bladder outlet obstruction and are healthy enough to undergo surgery. The ability to safely perform concomitant surgery with HoLEP benefits the patient by sparing them an additional anesthetic and also decreases costs. Patients should be made aware of the risk of retrograde ejaculation following HoLEP and counseled on treatment alternatives if maintaining ejaculatory function is desired. PMID:27800470

  8. Femtosecond laser based enucleation of porcine oocytes for somatic cell nuclear transfer

    NASA Astrophysics Data System (ADS)

    Kütemeyer, K.; Lucas-Hahn, A.; Petersen, B.; Hassel, P.; Lemme, E.; Niemann, H.; Heisterkamp, A.

    2009-07-01

    Cloning of several mammalian species has been achieved by somatic cell nuclear transfer (SCNT) in recent years. However, this method still results in very low efficiencies around 1% which originate from suboptimal culture conditions and highly invasive techniques for oocyte enucleation and injection of the donor cell using micromanipulators. In this paper, we present a new minimal invasive method for oocyte imaging and enucleation based on the application of femtosecond (fs) laser pulses. After imaging of the oocyte with multiphoton microscopy, ultrashort pulses are focused onto the metaphase plate of MII-oocytes in order to ablate the DNA molecules. We show that fs laser based enucleation of porcine oocytes completely inhibits the first mitotic cleavage after parthenogenetic activation while maintaining intact oocyte morphology in most cases. In contrast, control groups without previous irradiation of the metaphase plate are able to develop to the blastocyst stage. Further experiments have to clarify the suitability of fs laser based enucleated oocytes for SCNT.

  9. Combined multiphoton imaging and automated functional enucleation of porcine oocytes using femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Kuetemeyer, Kai; Lucas-Hahn, Andrea; Petersen, Bjoern; Lemme, Erika; Hassel, Petra; Niemann, Heiner; Heisterkamp, Alexander

    2010-07-01

    Since the birth of ``Dolly'' as the first mammal cloned from a differentiated cell, somatic cell cloning has been successful in several mammalian species, albeit at low success rates. The highly invasive mechanical enucleation step of a cloning protocol requires sophisticated, expensive equipment and considerable micromanipulation skill. We present a novel noninvasive method for combined oocyte imaging and automated functional enucleation using femtosecond (fs) laser pulses. After three-dimensional imaging of Hoechst-labeled porcine oocytes by multiphoton microscopy, our self-developed software automatically identified the metaphase plate. Subsequent irradiation of the metaphase chromosomes with the very same laser at higher pulse energies in the low-density-plasma regime was used for metaphase plate ablation (functional enucleation). We show that fs laser-based functional enucleation of porcine oocytes completely inhibited the parthenogenetic development without affecting the oocyte morphology. In contrast, nonirradiated oocytes were able to develop parthenogenetically to the blastocyst stage without significant differences to controls. Our results indicate that fs laser systems have great potential for oocyte imaging and functional enucleation and may improve the efficiency of somatic cell cloning.

  10. Holmium laser enucleation of the prostate: a paradigm shift in benign prostatic hyperplasia surgery

    PubMed Central

    2013-01-01

    Holmium laser enucleation (HoLEP) was developed in the 1990s as a more efficient and cost effective method of benign prostatic hyperplasia surgery than laser vaporization and resection techniques. As a true anatomical enucleation it mimics open prostatectomy and is as durable. There is a significant body of level 1 evidence in support of HoLEP, including 2 meta-analyses and 14 randomized trials which compare HoLEP with a number of other procedures. This review describes the development of and summarizes the evidence for HoLEP. PMID:24082919

  11. Office Hysteroscopic Laser Enucleation of Submucous Myomas without Mass Extraction: A Case Series Study

    PubMed Central

    Haimovich, Sergio; López-Yarto, Maite; Urresta Ávila, Julio; Saavedra Tascón, Alejandro; Hernández, José L.; Carreras Collado, Ramón

    2015-01-01

    Background and Objectives. A new two-step hysteroscopic myomectomy carried out in the office setting and without anesthesia was feasible for the excision of submucous myomas. The objective of this study was to assess whether removal of submucous myomas from the uterine cavity after hysteroscopic laser enucleation is necessary. Methods. Between June 2009 and April 2013, all outpatients with symptomatic myomatosis (bleeding, pelvic pain, and infertility) assessed ultrasonographically were eligible to participate in a prospective study. All patients underwent office hysteroscopic enucleation of submucous myomas. Enucleated myomas were left in the uterine cavity. Neither anesthesia nor antibiotic prophylaxis was used. Results. Sixty-one women (mean age: 47.3 years) were included. Regardless of hysteroscopic localization and grading, all myomas were enucleated. The mean (standard deviation, SD) diameter of the myoma as measured by the ultrasound scan was 22.6 (8.5) mm. In 29 cases (47.5%), the diameter of the resected myoma was >20 mm and in 10 cases (16.4%) >30 mm. After a mean follow-up of 68.2 (16.5) days, none of the patients showed a residual myoma inside the uterine cavity. Conclusions. The present results indicate that leaving laser-enucleated submucous myoma in the uterine cavity is a feasible and safe therapeutic option. PMID:26090457

  12. Functional enucleation of porcine oocytes for somatic cell nuclear transfer using femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Kuetemeyer, K.; Lucas-Hahn, A.; Petersen, B.; Hassel, P.; Lemme, E.; Niemann, H.; Heisterkamp, A.

    2010-02-01

    Cloning of several mammalian species has been achieved by somatic cell nuclear transfer over the last decade. However, this method still results in very low efficiencies originating from biological and technical aspects. The highly-invasive mechanical enucleation belongs to the technical aspects and requires considerable micromanipulation skill. In this paper, we present a novel non-invasive method for combined oocyte imaging and automated functional enucleation using femtosecond (fs) laser pulses. After three-dimensional imaging of Hoechst-labeled porcine oocytes by multiphoton microscopy, our self-developed software automatically determined the metaphase plate position and shape. Subsequent irradiation of this volume with the very same laser at higher pulse energies in the low-density-plasma regime was used for metaphase plate ablation. We show that functional fs laser-based enucleation of porcine oocytes completely inhibited further embryonic development while maintaining intact oocyte morphology. In contrast, non-irradiated oocytes were able to develop to the blastocyst stage without significant differences to control oocytes. Our results indicate that fs laser systems offer great potential for oocyte imaging and enucleation as a fast, easy to use and reliable tool which may improve the efficiency of somatic cell clone production.

  13. Holmium laser enucleation of the prostate: a review of the clinical trial evidence

    PubMed Central

    2014-01-01

    Transurethral resection of the prostate (TURP) has remained the procedure of choice for the surgical treatment of bladder outflow obstruction for almost five decades, but holmium laser enucleation of the prostate (HoLEP) is now emerging as a challenger as the gold standard procedure. This review summarizes the evidence base for HoLEP, with particular reference to randomized, controlled (level 1) evidence. PMID:24688602

  14. Holmium laser enucleation of the prostate: a size-independent new "gold standard".

    PubMed

    Elzayat, Ehab A; Habib, Enmar I; Elhilali, Mostafa M

    2005-11-01

    We report our experience with holmium laser enucleation of the prostate (HoLEP) for treatment of 552 patients with symptomatic benign prostatic hyperplasia (BPH) and their long-term outcome. Between March 1998 and January 2005, a retrospective review was conducted at our institution of 552 cases in which patients underwent HoLEP. Patient characteristics, indications for surgery, preoperative and postoperative International Prostate Symptom Score (I-PSS), peak flow rate (Qmax), postvoid residual urine, operative data, catheterization time, hospital stay, and immediate and long-term complications were recorded. The mean age of patients was 73.7 +/- 7.9 years, and the mean follow-up time was 36 months. The mean preoperative prostate size was 83.7 +/- 49.7 cm3 (range, 20 to 351 cm3), the mean enucleation time was 86 minutes (range, 15 to 255 minutes), and the mean enucleated tissue weight was 52.1 +/- 43.7 g (range, 5 to 340 g). The voiding parameters were significantly improved, with a 200% increase in Qmax, as well as a 75% improvement in I-PSS at 1 year postoperatively, which continued to improve during subsequent follow-up. A total of 11 patients required blood transfusion; 8 of them were on anticoagulant therapy. Irritative symptoms were noted in 9.4% and transient stress incontinence in 4.2% of patients. Bladder neck contracture and urethral stricture each developed in 1.3% of patients. We conclude that HoLEP is a safe and effective procedure for treatment of symptomatic BPH, regardless of prostate size, with low morbidity and short hospital stay. HoLEP appears to be the modern alternative to transurethral resection of the prostate and open prostatectomy, and it may be considered a size-independent new "gold standard."

  15. Evidence of the efficacy and safety of the thulium laser in the treatment of men with benign prostatic obstruction

    PubMed Central

    Barbalat, Yana; Velez, Marissa C.; Sayegh, Christopher I.; Chung, Doreen E.

    2016-01-01

    In 2005, the high power thulium laser was introduced for the surgical treatment of benign prostatic obstruction. It has several properties that confer theoretical advantages over other lasers used for the same indication, such as technical versatility and a relatively small zone of thermal damage. Studies using the 70–150 W thulium laser systems demonstrate good efficacy of these procedures with low morbidity and few complications even in higher risk patients. Different techniques have been employed to treat the prostate with this technology, including enucleation, vapoenucleation, vaporization and resection. Comparative studies have been published comparing thulium laser prostatectomy to monopolar transurethral resection of prostate (TURP), bipolar TURP and holmium laser enucleation of prostate (HoLEP). In this review we discuss the current literature on the safety and efficacy of various thulium techniques for the treatment of benign prostatic hyperplasia and examine comparative studies. PMID:27247628

  16. Holmium Laser Enucleation of the Prostate is Safe for Patients Above 80 Years: A Prospective Study

    PubMed Central

    2016-01-01

    Purpose: To evaluate the effect of age on the efficacy and safety of holmium laser enucleation of the prostate (HoLEP) for the treatment of symptomatic benign prostatic hyperplasia (BPH). Methods: A total of 579 patients underwent HoLEP procedure performed by a single surgeon (SJO) between December 2009 and May 2013. The perioperative and functional outcomes of patients in the age groups of 50–59 (group A, n=44), 60–69 (group B, n=253), 70–79 (group C, n=244), and ≥80 years (group D, n=38) were compared. The Clavien-Dindo system was used to evaluate clinical outcomes. The International Prostate Symptom Score (IPSS), maximum urinary flow rate (Qmax), postvoid residual (PVR) urine volume, and urinary continence were used to assess functional outcomes. Results: In this study, the patients ≥80 years had significantly higher presence of hypertension (P=0.007), total prostate volumes (P=0.024), transitional zone volume (P=0.002), American Society of Anesthesiologists scores (P=0.006), urinary retention (P=0.032), and anticoagulation use (P=0.008) at preoperative period. Moreover, the mean values of operation time, enucleation time, morcellation time, and enucleation weight were higher in group D compared with other group patients (P=0.002, P=0.010, P<0.01, and P=0.009, respectively). Patients aged ≥80 years had a longer hospital stay time (2.9±1.8 days) than other groups (group A, 2.3±0.7 days; group B, 2.3±0.7 days vs. group C, 2.4±0.7 days; P=0.001). All groups were similar in regard to the incidence of complications (Clavien-Dindo grade) post operatively (P>0.05). All the patients in the present study showed improvement in functional outcomes after HoLEP. By the sixth month, there were no significant differences in IPSS, quality of life, Qmax, and PVR among the groups (P>0.05). Conclusions: Compared with younger patients, the patients aged ≥80 years had a similar overall morbidity and 6-month functional outcomes of HoLEP. HoLEP is a safe and

  17. Sexual outcome of patients undergoing thulium laser enucleation of the prostate for benign prostatic hyperplasia.

    PubMed

    Carmignani, Luca; Bozzini, Giorgio; Macchi, Alberto; Maruccia, Serena; Picozzi, Stefano; Casellato, Stefano

    2015-01-01

    Treatment of patients with lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH) may affect the quality of sexual function and ejaculation. The effect of new surgical procedures, which are currently available to treat BPH, on erection and ejaculation, has been poorly studied. This study aimed to assess the effect of thulium laser enucleation of the prostate (ThuLEP) on sexual function and retrograde ejaculation in patients with LUTS secondary to BPH. We performed a prospective study in 110 consecutive patients who had undergone ThuLEP to analyze changes in sexual function and urinary symptoms. To evaluate changes in erection and ejaculation, and the effect of urinary symptoms on the quality of life (QoL), five validated questionnaires were used: the ICIQ-MLUTSsex, MSHQ-EjD, International Index of Erectile Function 5, International Prognostic Scoring System (IPSS) questionnaire, and QoL index of the intraclass correlation coefficients. Patients also underwent IPSS and flowmetry to assess the outcome of flow. Patients were evaluated before surgery and 3-6 months after ThuLEP, whereas those with previous abdominal surgery were excluded. The patients' mean age was 67.83 years. Postoperative urinary symptoms improved after surgery. No significant differences in erectile function before and after surgery were observed. As compared with other techniques described in the literature, the percentage of patients with conserved ejaculation increased by 52.7% after ThuLEP. ThuLEP positively affects urinary symptoms and their effect on the QoL of patients as assessed by questionnaire scores. While endoscopic management of BPH (e.g. transurethral resection of the prostate) causes retrograde ejaculation in most patients, those who undergo ThuLEP have conserved ejaculation and erectile function.

  18. The Impact of Increased Bladder Blood Flow on Storage Symptoms after Holmium Laser Enucleation of the Prostate

    PubMed Central

    Ide, Hisamitsu; Aoki, Hiroaki; Muto, Satoru; Yamaguchi, Raizo; Tsujimura, Akira; Horie, Shigeo

    2015-01-01

    In order to investigate how holmium laser enucleation of the prostate (HoLEP) improves urinary storage symptoms, we assessed blood flow in the urinary bladder mucosa of patients with benign prostatic hyperplasia (BPH) before and after laser surgery. Seventy-four consecutive patients with BPH (median age 69 years, range; 53–88) underwent HoLEP at our institution and are included in this study. We prospectively assessed the International Prostate Symptom Score (IPSS), IPSS-QOL Score, the Overactive Bladder Symptom Score (OABSS), uroflowmetry, and blood flow in the urinary bladder, before and after surgery. Blood flow in the bladder mucosa was measured using the OMEGA FLOW (OMEGAWAVE, Tokyo, Japan) laser Doppler flowmeter. The median volume of the enucleated adenomas was 45.0 g (range: 25.0 to 83.2). The median IPSS improved significantly from 20 (range: 6–35) to 3 (0–22) (p<0.001; Wilcoxon signed-rank test), as did the storage symptoms score, which decreased from 13 (2–20) to 3 (1–8) (p<0.001). Median bladder blood flow increased at the trigone from 9.57±0.83 ml/sec to 17.60±1.08 ml/sec. Multiple regression analysis for the improved storage symptom score eliminated all explanatory variables except increased bladder perfusion. The data suggest that HoLEP improves blood flow in the bladder mucosa, which independently leads to the improvement of storage symptoms. PMID:26090819

  19. The Impact of Increased Bladder Blood Flow on Storage Symptoms after Holmium Laser Enucleation of the Prostate.

    PubMed

    Saito, Keisuke; Hisasue, Shin-ichi; Ide, Hisamitsu; Aoki, Hiroaki; Muto, Satoru; Yamaguchi, Raizo; Tsujimura, Akira; Horie, Shigeo

    2015-01-01

    In order to investigate how holmium laser enucleation of the prostate (HoLEP) improves urinary storage symptoms, we assessed blood flow in the urinary bladder mucosa of patients with benign prostatic hyperplasia (BPH) before and after laser surgery. Seventy-four consecutive patients with BPH (median age 69 years, range; 53-88) underwent HoLEP at our institution and are included in this study. We prospectively assessed the International Prostate Symptom Score (IPSS), IPSS-QOL Score, the Overactive Bladder Symptom Score (OABSS), uroflowmetry, and blood flow in the urinary bladder, before and after surgery. Blood flow in the bladder mucosa was measured using the OMEGA FLOW (OMEGAWAVE, Tokyo, Japan) laser Doppler flowmeter. The median volume of the enucleated adenomas was 45.0 g (range: 25.0 to 83.2). The median IPSS improved significantly from 20 (range: 6-35) to 3 (0-22) (p < 0.001; Wilcoxon signed-rank test), as did the storage symptoms score, which decreased from 13 (2-20) to 3 (1-8) (p < 0.001). Median bladder blood flow increased at the trigone from 9.57 ± 0.83 ml/sec to 17.60 ± 1.08 ml/sec. Multiple regression analysis for the improved storage symptom score eliminated all explanatory variables except increased bladder perfusion. The data suggest that HoLEP improves blood flow in the bladder mucosa, which independently leads to the improvement of storage symptoms.

  20. Outcomes of transurethral resection and holmium laser enucleation in more than 60 g of prostate: A prospective randomized study

    PubMed Central

    Jhanwar, Ankur; Sinha, Rahul J.; Bansal, Ankur; Prakash, Gaurav; Singh, Kawaljit; Singh, Vishwajeet

    2017-01-01

    Aim: Transurethral resection of prostate (TURP) is considered a gold standard surgical procedure. The management of benign prostatic hyperplasia (BPH) has undergone tremendous change in recent years and shifted from open to minimal invasive procedure. With the advancement in technology and skills of surgeons, lasers have been used more liberally, particularly holmium laser. Holmium laser enucleation of prostate (HoLEP) is seen as close rival of TURP. The objective if this study is to observe long- and short-term outcomes of transurethral resection and holmium laser enucleation in the prostate of more than 60 g. Materials and Methods: This prospective randomized study includes 164 patients. Inclusion criteria were age <75 years after failed or poor response to medical therapy, prostatic size >60 g, gross hematuria secondary to BPH, recurrent urinary tract infection, acute urinary retention, postvoid residual >150 ml, and Schafer Grade II or more. BPH associated with neurogenic bladder, stricture urethra, and carcinoma prostate were excluded from the study. Group 1 comprises patients who underwent TURP and Group 2 comprises who underwent HoLEP. Follow-up was done at 1, 3, 6, 12, and 24 months after the surgery. Results: Data of 144 patients were analyzed. The mean age of patients in TURP and HoLEP group was 66.78 ± 7.81 and 67.70 ± 7.44 years, respectively (P = 0.47), mean prostatic volume was 74.5 ± 12.56 and 75.6 ± 12.84 g, respectively (P = 0.60), operative time was 73.10 ± 10.49 and 89.56 ± 13.81 min, respectively (P = 0.0001). Mean resected tissue was 44.80 ± 9.87 and 48.49 ± 10.87, respectively (P = 0.03). The sexual function did not changed significantly in postoperative follow-up. Conclusion: HoLEP is associated with less blood loss, lower transfusion rates, and a shorter hospital stay. The disadvantage of HoLEP is longer operative time and postoperative dysuria. PMID:28216929

  1. In 2013, holmium laser enucleation of the prostate (HoLEP) may be the new 'gold standard'.

    PubMed

    van Rij, Simon; Gilling, Peter J

    2012-12-01

    In this review article, we assess why holmium laser enucleation of the prostate (HoLEP) has become an important treatment modality for benign prostatic hypertrophy (BPH). Meta-analysis comparing HoLEP with both open prostatectomy (OP) and transurethral resection of prostate (TURP) shows TURP to be as effective with less morbidity. More recently, HoLEP has long-term durability data confirming a very low reoperation rate. This article investigates how previous hurdles to the widespread uptake of HoLEP have been overcome. Recent literature shows that the learning curve is actually similar to many other current urological procedures, and that the efficiency of HoLEP is equal to that of other surgical procedures. HoLEP is also beneficial in the growing population of men on anticoagulation who require treatment for BPH. Finally, HoLEP is the only laser treatment for BPH with level 1 evidence and endorsement in both the American Urological Association (AUA) and European Association of Urology (EAU) guidelines.

  2. Comparison of Photoselective Vaporization versus Holmium Laser Enucleation for Treatment of Benign Prostate Hyperplasia in a Small Prostate Volume

    PubMed Central

    Kim, Kang Sup; Choi, Jin Bong; Bae, Woong Jin; Kim, Su Jin; Cho, Hyuk Jin; Hong, Sung-Hoo; Lee, Ji Youl; Kim, Sang Hoon; Kim, Hyun Woo; Cho, Su Yeon; Kim, Sae Woong

    2016-01-01

    Objective Photoselective vaporization of the prostate (PVP) using GreenLight and Holmium laser enucleation of the prostate (HoLEP) is an important surgical technique for management of benign prostate hyperplasia (BPH). We aimed to compare the effectiveness and safety of PVP using a 120 W GreenLight laser with HoLEP in a small prostate volume. Methods Patients who underwent PVP or HoLEP surgery for BPH at our institutions were reviewed from May 2009 to December 2014 in this retrospective study. Among them, patients with prostate volumes < 40 mL based on preoperative trans-rectal ultrasonography were included in this study. Peri-operative and post-operative parameters—such as International Prostate Symptom Score (IPSS), quality of life (QoL), maximum urinary flow rate (Qmax), post-void residual urine volume (PVR), and complications—were compared between the groups. Results PVP was performed in 176 patients and HoLEP in162 patients. Preoperative demographic data were similar in both groups, with the exception of PVR. Operative time and catheter duration did not show significant difference. Significant improvements compared to preoperative values were verified at the postoperative evaluation in both groups in terms of IPSS, QoL, Qmax, and PVR. Comparison of the postoperative parameters between the PVP and HoLEP groups demonstrated no significant difference, with the exception of IPSS voiding subscore at 1 month postoperatively (5.9 vs. 3.8, P< 0.001). There was no significant difference in postoperative complications between the two groups. Conclusion Our data suggest that PVP and HoLEP are efficient and safe surgical treatment options for patients with small prostate volume. PMID:27227564

  3. Holmium Laser Enucleation of the Prostate: Comparison of Immediate Postoperative Outcomes in Patients with and without Antithrombotic Therapy

    PubMed Central

    Bishop, Conrad V.; Liddell, Heath; Ischia, Joseph; Paul, Eldho; Appu, Sree; Frydenberg, Mark; Pham, Trung

    2013-01-01

    Objective To compare the immediate postoperative outcomes of patients with benign prostatic hyperplasia undergoing Holmium laser enucleation of the prostate (HOLEP) with and without full anticoagulation or antiplatelet therapy at the time of surgery. Materials and Methods A retrospective review was performed on a series of consecutive patients undergoing HOLEP at our institution by a single surgeon from February 2004 to September 2010. Demographic, surgical, pathological and outcome data were collected. Two cohorts were identified on the basis of antithrombotic therapy at the time of surgery. Patients who continued on aspirin, aspirin/dipyridamole, clopidogrel and warfarin throughout the surgery were included in the antithrombotic cohort. Univariate analysis was performed to determine differences in outcomes between the 2 cohorts. Results Total 125 consecutive patients underwent HOLEP with 52 patients on antithrombotic therapy at the time of surgery and 73 patients were not on antithrombotic therapy during surgery. Patients in the antithrombotic group were older (75.1 ±7.5 vs. 71.7 ± 8.3 years; p = 0.02) and had a higher median ASA physical status (3 (3-3) vs. 2 (2-3), p < 0.0001). The mean operating time and median specimen volume were not significantly different between the 2 cohorts. The median length of stay (2 (1-3) vs. 1 (1-2) d, p = 0.014) was longer in the antithrombotic cohort. The transfusion rate (7.7 vs. 0%, p = 0.028) was predictably higher in the antithrombotic cohort. No patients required re-operation for bleeding. Conclusions The use of HOLEP in patients on antithrombotic therapy is safe despite the higher surgical risk profile of that particular patient population and the potential increased risk for significant bleeding. PMID:24917753

  4. Holmium laser enucleation of the prostate: surgical, functional, and quality-of-life outcomes upon extended follow-up

    PubMed Central

    Alkan, Ilter; Ozveri, Hakan; Akin, Yigit; Ipekci, Tumay; Alican, Yusuf

    2016-01-01

    ABSTRACT Objectives: To evaluate the long-term surgical, functional, and quality-of-life (QoL) outcomes after Holmium laser enucleation of the prostate (HoLEP) in patients with symptomatic benign prostatic hyperplasia (BPH). Materials and Methods: We retrospectively reviewed recorded data on patients who underwent HoLEP between June 2002 and February 2005. Ninety-six patients were enrolled. Demographic, perioperative, and postoperative data were recorded. On follow-up, International Prostate Symptom Scores (IPSSs), prostate-specific antigen (PSA) levels, QoL scores, peak uroflowmetric data (Qmax values), and post-voiding residual urine volumes (PVR volumes), were recorded. Complications were scored using the Clavien system. Statistical significance was set at p<0.05. Results: The mean follow-up time was 41.8±34.6 months and the mean patient age 73.2±8.7 years. The mean prostate volume was 74.6±34.3mL. Significant improvements in Qmax values, QoL, and IPSSs and decreases in PSA levels and PVR volumes were noted during follow-up (all p values=0.001). The most common complication was a requirement for re-catheterisation because of urinary retention. Two patients had concomitant bladder tumours that did not invade the muscles. Eight patients (8.3%) required re-operations; three had residual adenoma, three urethral strictures, and two residual prostate tissue in the bladder. Stress incontinence occurred in one patient (1%). All complications were of Clavien Grade 3a. We noted no Clavien 3b, 4, or 5 complications during follow-up. Conclusions: HoLEP improved IPSSs, Qmax values, PVR volumes, and QoL and was associated with a low complication rate, during extended follow-up. Thus, HoLEP can be a viable option to transurethral resection of the prostate. PMID:27256184

  5. Comparison of Surgical Outcomes Between Holmium Laser Enucleation and Transurethral Resection of the Prostate in Patients With Detrusor Underactivity

    PubMed Central

    2017-01-01

    Purpose Currently, holmium laser enucleation of the prostate (HoLEP) and transurethral resection of the prostate (TURP) are the standard surgical procedures used to treat benign prostatic hyperplasia (BPH). Several recent studies have demonstrated that the surgical management of BPH in patients with detrusor underactivity (DU) can effectively improve voiding symptoms, but comparative data on the efficacy of HoLEP and TURP are insufficient. Therefore, we compared the short-term surgical outcomes of HoLEP and TURP in patients with DU. Methods From January 2010 to May 2015, 352 patients underwent HoLEP or TURP in procedures performed by a single surgeon. Of these patients, 56 patients with both BPH and DU were enrolled in this study (HoLEP, n=24; TURP, n=32). Surgical outcomes were retrospectively compared between the 2 groups. DU was defined as a detrusor pressure at maximal flow rate of <40 cm H2O as measured by a pressure flow study. Results The preoperative characteristics of patients and the presence of comorbidities were comparable between the 2 groups. The TURP group showed a significantly shorter operative time than the HoLEP group (P=0.033). The weight of the resected prostate was greater in the HoLEP group, and postoperative voiding parameters, including peak flow rate and postvoid residual urine volume were significantly better in the HoLEP group than in the TURP group. Conclusions HoLEP can be effectively and safely performed in patients with DU and can be expected to have better surgical outcomes than TURP in terms of the improvement in lower urinary tract symptoms. PMID:28361512

  6. Predictors of urgency improvement after Holmium laser enucleation of the prostate in men with benign prostatic hyperplasia

    PubMed Central

    Hur, Won Sok; Kim, Joon Chul; Kim, Hyo Sin; Koh, Jun Sung; Kim, Sang Hoon; Kim, Hyun Woo; Cho, Su Yeon

    2016-01-01

    Purpose To investigate the change in urinary urgency and predictors of urgency improvement after holmium laser enucleation of the prostate (HoLEP) in men with benign prostatic hyperplasia (BPH). Materials and Methods We retrospectively analyzed the medical records of patients who were treated with HoLEP for BPH and had preoperative urgency measuring ≥3 on a 5-point urinary sensation scale. Those with prostate cancer diagnosed prior to or after HoLEP, a history of other prostatic and/or urethral surgery, moderate to severe postoperative complications, and neurogenic causes were excluded. Patients who had improved urgency with antimuscarinic medication after HoLEP were excluded. We divided the patients into 2 groups based on urgency symptoms 3 months after HoLEP: improved and unimproved urgency. Improved urgency was defined as a reduction of 2 or more points on the 5-point urinary sensation scale. Preoperative clinical and urodynamic factors as well as perioperative factors were compared between groups. Results In total, 139 patients were included in this study. Voiding parameters in all patients improved significantly after HoLEP. Seventy-one patients (51.1%) had improved urgency, while 68 (48.9%) did not show any improvement. A history of acute urinary retention (AUR) and postvoid residual were associated with postoperative urgency improvement in univariate analysis. In multivariate analysis, a history of AUR was an independent factor affecting urgency improvement. Conclusions A preoperative history of AUR could influence the change in urgency after HoLEP surgery in patients with BPH. PMID:27847917

  7. Holmium laser enucleation versus simple prostatectomy for treating large prostates: Results of a systematic review and meta-analysis

    PubMed Central

    Jones, Patrick; Alzweri, Laith; Rai, Bhavan Prasad; Somani, Bhaskar K.; Bates, Chris; Aboumarzouk, Omar M.

    2015-01-01

    Objective To compare and evaluate the safety and efficacy of holmium laser enucleation of the prostate (HoLEP) and simple prostatectomy for large prostate burdens, as discussion and debate continue about the optimal surgical intervention for this common pathology. Materials and methods A systematic search was conducted for studies comparing HoLEP with simple prostatectomy [open (OP), robot-assisted, laparoscopic] using a sensitive strategy and in accordance with Cochrane collaboration guidelines. Primary parameters of interest were objective measurements including maximum urinary flow rate (Qmax) and post-void residual urine volume (PVR), and subjective outcomes including International Prostate Symptom Score (IPSS) and quality of life (QoL). Secondary outcomes of interest included volume of tissue retrieved, catheterisation time, hospital stay, blood loss and serum sodium decrease. Data on baseline characteristics and complications were also collected. Where possible, comparable data were combined and meta-analysis was conducted. Results In all, 310 articles were identified and after screening abstracts (114) and full manuscripts (14), three randomised studies (263 patients) were included, which met our pre-defined inclusion criteria. All these compared HoLEP with OP. The mean transrectal ultrasonography (TRUS) volume was 113.9 mL in the HoLEP group and 119.4 mL in the OP group. There was no statistically significant difference in Qmax, PVR, IPSS and QoL at 12 and 24 months between the two interventions. OP was associated with a significantly shorter operative time (P = 0.01) and greater tissue retrieved (P < 0.001). However, with HoLEP there was significantly less blood loss (P < 0.001), patients had a shorter hospital stay (P = 0.03), and were catheterised for significantly fewer hours (P = 0.01). There were no significant differences in the total number of complications recorded amongst HoLEP and OP (P = 0.80). Conclusion The results of the meta

  8. Plasmakinetic enucleation of prostate versus 160-W laser photoselective vaporization for the treatment of benign prostatic hyperplasia

    PubMed Central

    Wang, Si-Jun; Mu, Xiao-Nan; Chen, Ji; Jin, Xun-Bo; Zhang, Shi-Bao; Zhang, Long-Yang

    2017-01-01

    To evaluate the safety and efficacy of plasmakinetic enucleation of the prostate (PKEP) for the treatment of symptomatic benign prostatic hyperplasia (BPH) compared with 160-W lithium triboride laser photoselective vaporization of the prostate (PVP). From February 2011 to July 2012, a prospective nonrandomized study was performed. One-hundred one patients underwent PKEP, and 110 underwent PVP. No severe intraoperative complications were recorded, and none of the patients in either group required a blood transfusion. Shorter catheterization time (38.14 ± 23.64 h vs 72.54 ± 28.38 h, P < 0.001) and hospitalization (2.32 ± 1.25 days vs 4.07 ± 1.23 days, P < 0.001) were recorded in the PVP group. At 12-month postoperatively, the PKEP group had a maintained and statistically improvement in International Prostate Symptom Score (IPSS) (4.07 ± 2.07 vs 5.00 ± 2.10; P < 0.001), quality of life (QoL) (1.08 ± 0.72 vs 1.35 ± 0.72; P = 0.007), maximal urinary flow rate (Qmax) (24.75 ± 5.87 ml s−1 vs 22.03 ± 5.04 ml s−1; P < 0.001), postvoid residual urine volume (PVR) (14.29 ± 6.97 ml vs 17.00 ± 6.11 ml; P = 0.001), and prostate-specific antigen (PSA) value (0.78 ± 0.57 ng ml−1 vs 1.27 ± 1.07 ng ml−1; P < 0.001). Both PKEP and PVP relieve low urinary tract symptoms (LUTS) due to BPH with low complication rates. PKEP can completely remove prostatic adenoma while the total amount of tissue removed by PVP is less than that can be removed by PKEP. Based on our study of the follow-up, PKEP provides better postoperative outcomes than PVP. PMID:26732101

  9. Enucleation Procedure Manual.

    ERIC Educational Resources Information Center

    Davis, Kevin; Poston, George

    This manual provides information on the enucleation procedure (removal of the eyes for organ banks). An introductory section focuses on the anatomy of the eye and defines each of the parts. Diagrams of the eye are provided. A list of enucleation materials follows. Other sections present outlines of (1) a sterile procedure; (2) preparation for eye…

  10. Comparison of thulium laser enucleation and plasmakinetic resection of the prostate in a randomized prospective trial with 5-year follow-up.

    PubMed

    Yang, Zhonghua; Liu, Tongzu; Wang, Xinghuan

    2016-12-01

    The aim of this study was to compare the clinical outcomes between thulium laser enucleation of the prostate (ThuLEP) and plasmakinetic bipolar resection of the prostate (PKRP) for treating benign prostatic hyperplasia (BPH) in a prospective randomized trial with 5 years of follow-up. One hundred fifty-eight consecutive patients with BPH were randomized to receive operation of either ThuLEP (n = 79) or PKRP (n = 79). All cases were evaluated preoperatively, and a part of them were evaluated at 3-5 years postoperatively by the International Prostate Symptom Score (IPSS), quality of life score (QoLS), maximum flow rate (Q max), and postvoid residual (PVR) urine volume. Eighty patients completed the 5-year follow-up. Each study arm showed no significant difference in preoperative parameters. Compared with PKRP, ThuLEP required longer operation time (65.4 vs 47.4 min, p = 0.022) but resulted in less hemoglobin decrease (1.5 vs 3.0 g/L, p = 0.045), catheterization time (2.1 vs 3.5 days, p = 0.031), irrigated volume (12.4 vs 27.2 L, p = 0.022), and hospital stay (2.5 vs 4.6 days, p = 0.026). During the 60-month follow-up, both procedures demonstrated no significant difference in terms of Q max, IPSS, PVR urine volume, and QoLS. ThuLEP was statistically superior to PKRP in blood loss, catheterization time, irrigated volume, and hospital stay but inferior to PKRP in operation time. However, both procedures showed no significant difference in terms of Q max, IPSS, PVR urine volume, and QoLS through the 60-month follow-up.

  11. A comparative study of diode laser and plasmakinetic in transurethral enucleation of the prostate for treating large volume benign prostatic hyperplasia: a randomized clinical trial with 12-month follow-up.

    PubMed

    Wu, Gang; Hong, Zhe; Li, Chao; Bian, Cuidong; Huang, Shengsong; Wu, Denglong

    2016-05-01

    The objective of this study is to compare the efficacy and safety of diode laser enucleation of the prostate (DiLEP) with plasmakinetic enucleation of the prostate (PKEP) for symptomatic benign prostatic hyperplasia (BPH) patients with large prostate (volume > 80 ml). From January 2013 to June 2014, 80 consecutive patients were randomized treated with DiLEP (n = 40) or PKEP (n = 40). Perioperative and postoperative outcome data were assessed during a 1-year follow-up. There were no significant preoperative differences between the two surgical groups. The mean prostate volumes in the DiLEP and PKEP groups were 98.6 and 93.3 ml, respectively. DiLEP was equivalent to PKEP in improvement in International Prostate Symptom Score (IPSS), quality of life scores, and maximum flow rate. Compared with PKEP, patients treated with DiLEP showed a lower risk of blood loss (P < 0.01), shorter bladder irrigation and catheterization times (P < 0.01), as well as shorter hospital stays (P < 0.01). Moreover, the DiLEP group was significantly superior to bipolar plasmakinetic group in the irritative symptoms. However, the operation time of the DiLEP group was longer than that of PKEP group (P = 0.02). Both DiLEP and PKEP are safe and effective methods for the treatment of BPH in large prostates (volume > 80 ml). Compared with PKEP, DiLEP provides a decreased risk of hemorrhage, reduced bladder irrigation, and catheterization times, as well as shorter hospital stays.

  12. Calcium Signaling Is Required for Erythroid Enucleation

    PubMed Central

    Russell, Sarah M.; Humbert, Patrick O.

    2016-01-01

    Although erythroid enucleation, the property of erythroblasts to expel their nucleus, has been known for 7ore than a century, surprisingly little is known regarding the molecular mechanisms governing this unique developmental process. Here we show that similar to cytokinesis, nuclear extrusion requires intracellular calcium signaling and signal transduction through the calmodulin (CaM) pathway. However, in contrast to cytokinesis we found that orthochromatic erythroblasts require uptake of extracellular calcium to enucleate. Together these functional studies highlight a critical role for calcium signaling in the regulation of erythroid enucleation. PMID:26731108

  13. Enucleation in psychosis associated with aqueductal stenosis.

    PubMed

    Mancinelli, Iginia; Pompili, Maurizio; Scapati, Francesco; Lazanio, Simone; Kotzalidis, Giorgio D; Tatarelli, Roberto

    2004-03-01

    Reports of self-enucleation are frequent in medical literature, but cases of enucleation towards another are rare. We report the case of a man, 20 years of age, who suffered from psychosis with hydrocephalus and aqueductal stenosis that required a forensic psychiatric investigation to ascertain whether he was of unsound mind when he assaulted and enucleated the right eye of an officer and led to the surgical enucleation of the victim's left eye. Based on his clinical interviews and hospitalization record, we conclude that at the time of the assault, he was suffering from a delusional disorder with religious and demonic content, visual and auditory hallucinations, illusion phenomena, delusional interpretations, imaginative elements, a feeling of terror, and command hallucinations that compelled him to perform the act of aggression.

  14. Enucleation versus plaque irradiation for choroidal melanoma

    SciTech Connect

    Straatsma, B.R.; Fine, S.L.; Earle, J.D.; Hawkins, B.S.; Diener-West, M.; McLaughlin, J.A.

    1988-07-01

    The Collaborative Ocular Melanoma Study (COMS) is an international, multicenter-controlled study. The organization includes an Executive Committee, Steering Committee, 6 Central Units, 32 Clinical Centers, and a Data and Safety Monitoring Committee. Scientifically, the COMS consists of (1) a randomized trial of patients with medium choroidal melanoma treated with enucleation versus iodine-125 plaque irradiation, (2) a randomized trial of patients with large choroidal melanoma treated with enucleation versus preenucleation external beam irradiation and enucleation, and (3) a prospective observational study of patients with small choroidal melanoma to determine whether a randomized trial of treatment is appropriate. In design and conduct of the COMS, special consideration is given to biostatistics and sample size considerations, iodine-125 plaque irradiation of choroidal melanoma, and coordinated ocular melanoma research. Recruitment is in progress. However, the pool of eligible patients is limited and the COMS needs the continued support and cooperation of ophthalmologists throughout the United States and Canada.

  15. THE EFFECT OF ENUCLEATION ON THE DPN LEVEL OF AMEBA

    PubMed Central

    Cohen, Adolph I.

    1956-01-01

    1. Amebae contain DPN at levels of from 1 to 4 x 10–13 moles per cell. 2. Following enucleation, nucleate and enucleate halves continue to have equal DPN contents over the six day period studied. Similarly, starving whole amebae maintain their DPN level over this period. 3. No reduced DPN could be detected in these aerobic animals. This remained true for whole amebae and for nucleate and enucleate halves over 5 days of starvation. 4. A method is described for the preparation and rapid separation of nucleate and enucleate ameba halves, based on a response of amebae to light. PMID:13295307

  16. The sorting of blood group active proteins during enucleation.

    PubMed

    Satchwell, Timothy J; Bell, Amanda J; Toye, Ashley M

    2015-04-01

    Enucleation represents the critical stage during red blood cell development when the nucleus is extruded from an orthochromatic erythroblast in order to generate a nascent immature reticulocyte. Extrusion of the nucleus results in loss of a proportion of the erythroblast plasma membrane, which surrounds the nucleus, the bulk of the endoplasmic reticulum and a small region of cytoplasm. For this reason enucleation provides an important point in erythroblast differentiation at which proteins not required for the function of the erythrocyte can be lost, whilst those that are important for the structure-function properties of the mature erythrocyte must be efficiently retained in the reticulocyte plasma membrane. Disturbances in protein distribution during enucleation are envisaged to occur during human diseases such as Hereditary Spherocytosis. This article will discuss the current knowledge of erythroblast enucleation in the context of retention and loss of proteins that display antigenic blood group sites and that exist within multiprotein complexes within the erythrocyte membrane.

  17. Formation of mammalian erythrocytes: chromatin condensation and enucleation.

    PubMed

    Ji, Peng; Murata-Hori, Maki; Lodish, Harvey F

    2011-07-01

    In all vertebrates, the cell nucleus becomes highly condensed and transcriptionally inactive during the final stages of red cell biogenesis. Enucleation, the process by which the nucleus is extruded by budding off from the erythroblast, is unique to mammals. Enucleation has critical physiological and evolutionary significance in that it allows an elevation of hemoglobin levels in the blood and also gives red cells their flexible biconcave shape. Recent experiments reveal that enucleation involves multiple molecular and cellular pathways that include histone deacetylation, actin polymerization, cytokinesis, cell-matrix interactions, specific microRNAs and vesicle trafficking; many evolutionarily conserved proteins and genes have been recruited to participate in this uniquely mammalian process. In this review, we discuss recent advances in mammalian erythroblast chromatin condensation and enucleation, and conclude with our perspectives on future studies.

  18. Unsuccessful Self-Enucleation in a Schizophrenic Patient

    PubMed Central

    Noy Achiron, Romi; Paul, Michael; Achiron, Asaf

    2014-01-01

    Self-enucleation is a very unusual form of self-mutilation directly linked to mental illness. In this case we present a 26-year-old schizophrenic patient who attempted to enucleate his eye with a rollerball pen. Antipsychotic therapy and emergency surgery saved the patient eye and emphasize the importance of quick response and good collaboration between psychiatric and ophthalmic teams. PMID:25328735

  19. Tumor Enucleation for Renal Cell Carcinoma

    PubMed Central

    Malkowicz, S. Bruce

    2015-01-01

    The increased number of small renal masses (SRMs) detected annually has led to a rise in the use of nephron-sparing surgery (NSS). These techniques aim to preserve the largest amount of healthy renal tissue possible while maintaining the same oncologic outcomes as radical nephrectomy (RN). Additionally, partial nephrectomy (PN) has been linked to a lower risk of chronic kidney disease, cardiovascular morbidity, and mortality when compared to RN. There has been continual progress toward resecting less renal parenchyma. While the predominant surgical method of performing NSS is through traditional PN, simple enucleation (SE) of the tumor has increased in popularity over recent years. SE is a technique that aims to preserve the maximal amount of renal parenchyma possible by utilizing the renal tumor pseudocapsule to bluntly separate the lesion from its underlying parenchyma, offering the smallest possible margin of excised healthy renal tissue. Several studies have demonstrated the oncological safety of SE compared with PN in the treatment of SRMs, with lower overall incidence of positive surgical margins. Additionally, SE has been shown to have similar 5- and 10-year progression-free and cancer-specific survival as PN. We present a review of the literature and an argument for SE to be a routine consideration in the treatment of all renal tumors amenable to NSS.

  20. On-chip enucleation of an oocyte by untethered microrobots

    NASA Astrophysics Data System (ADS)

    Ichikawa, Akihiko; Sakuma, Shinya; Sugita, Masakuni; Shoda, Tatsuro; Tamakoshi, Takahiro; Akagi, Satoshi; Arai, Fumihito

    2014-09-01

    We propose a novel on-chip enucleation of an oocyte with zona pellucida by using a combination of untethered microrobots. To achieve enucleation within the closed space of a microfluidic chip, two microrobots, a microknife and a microgripper were integrated into the microfluidic chip. These microrobots were actuated by an external magnetic force produced by permanent magnets placed on the robotic stage. The tip of the microknife was designed by considering the biological geometric feature of an oocyte, i.e. the oocyte has a polar body in maturation stage II. Moreover, the microknife was fabricated by using grayscale lithography, which allows fabrication of three-dimensional microstructures. The microgripper has a gripping function that is independent of the driving mechanism. On-chip enucleation was demonstrated, and the enucleated oocytes are spherical, indicating that the cell membrane of the oocytes remained intact. To confirm successful enucleation using this method, we investigated the viability of oocytes after enucleation. The results show that the production rate, i.e. the ratio between the number of oocytes that reach the blastocyst stage and the number of bovine oocytes after nucleus transfer, is 100%. The technique will contribute to complex cell manipulation such as cell surgery in lab-on-a-chip devices.

  1. Molecular signature of erythroblast enucleation in human embryonic stem cells.

    PubMed

    Rouzbeh, Shaghayegh; Kobari, Ladan; Cambot, Marie; Mazurier, Christelle; Hebert, Nicolas; Faussat, Anne-Marie; Durand, Charles; Douay, Luc; Lapillonne, Hélène

    2015-08-01

    While enucleation is a critical step in the terminal differentiation of human red blood cells, the molecular mechanisms underlying this unique process remain unclear. To investigate erythroblast enucleation, we studied the erythroid differentiation of human embryonic stem cells (hESCs), which provide a unique model for deeper understanding of the development and differentiation of multiple cell types. First, using a two-step protocol, we demonstrated that terminal erythroid differentiation from hESCs is directly dependent on the age of the embryoid bodies. Second, by choosing hESCs in two extreme conditions of erythroid culture, we obtained an original differentiation model which allows one to study the mechanisms underlying the enucleation of erythroid cells by analyzing the gene and miRNA (miR) expression profiles of cells from these two culture conditions. Third, using an integrated analysis of mRNA and miR expression profiles, we identified five miRs potentially involved in erythroblast enucleation. Finally, by selective knockdown of these five miRs we found miR-30a to be a regulator of erythroblast enucleation in hESCs.

  2. Enucleation and evisceration: indications, complications and clinicopathological correlations

    PubMed Central

    Kord Valeshabad, Ali; Naseripour, Masood; Asghari, Rajab; Parhizgar, Seyed Hamid; Parhizgar, Seyed Ehsan; Taghvaei, Mohammad; Miri, Shahin

    2014-01-01

    AIM To assess main indications, postoperative complications and clinicopathological correlation of ocular enucleation-evisceration. METHODS A total of 107 subjects who underwent enucleation and/or evisceration and received hydroxyapatite implants (Scleral wrap or mesh) were assessed. For each patient clinicopathological data was collected which included demographic information, clinical history, primary clinical diagnosis, main cause of ophthalmic surgery (traumatic, non-traumatic), type of surgical procedure (enucleation, evisceration) and pathological report. Patients' postoperative clinical visits were checked for procedure-related complications during first year after surgery. RESULTS One hundred and seven patients (male: 65.4%; mean age: 26y) underwent enucleation (n=100) or evisceration (n=7) due to traumatic (n=41) and non-traumatic (n=66) causes. Disfiguring painful blind eye was the most common indication of surgery (66.4%), followed by leukocoria (19.6%) and endophthalmitis (4.7%). The main types of injury included firecracker, traffic and work accidents, and sharp object perforating injury. In 53 (80.3%) subjects in non-traumatic group the initial clinical diagnosis matched the histopathological results. Malignant tumors (retinoblastoma: 47.5%, malignant melanoma: 27.3%) were the most common pathological diagnoses followed by phthisis bulbi (25.8%). The most common procedure-related complications were major eye discharge (39.6%), and implant exposure and discharge (20.8%). CONCLUSION Trauma and malignant tumors are the leading causes of enucleation-evisceration. Despite developing new techniques and materials, enucleation is still associated with considerable postoperative complications. PMID:25161942

  3. Risk factors for endophthalmitis requiring evisceration or enucleation

    PubMed Central

    Lu, Xuehui; Ng, Danny Siu-Chun; Zheng, Kangkeng; Peng, Kun; Jin, Chuang; Xia, Honghe; Chen, Weiqi; Chen, Haoyu

    2016-01-01

    Endophthalmitis has devastating sequelae resulting in blindness and even loss of eyeball. Although the prognosis of endophthalmitis has much improved with the advances of antibiotics and vitreoretinal surgery, of the number of patients that required evisceration or enucleation is still significant. We retrospectively reviewed the charts of 210 eyes of 210 patients with endophthalmitis andcompared the group that required evisceration or enucleation with those that received salvaging therapies. Regression analysis was used to identify the risk factors for evisceration or enucleation. Thirty eyes (14.3%) underwent enucleation or evisceration. The group of eviscerated or enucleated eyes were older (58.7 vs. 42.2 years, p < 0.001), had more women (56.7% vs. 22.2%, p = 0.003), had poorer initial visual acuity (2.79 vs. 2.10 LogMAR, p < 0.001), and had longer duration before intervention (18.03 vs. 5.74 days, p = 0.031). The most common primary indications for endophthalmitis were infections from corneal ulcer (50.0% vs. 4.4%, p < 0.001) andfrom endogenous source (23.3% vs. 5.6%, p < 0.001). Less common indications were trauma (26.7% vs. 67.8%, p < 0.001) and postoperative (6.7% vs. 22.2%, p = 0.049) endophthalmitis. After adjusting for confounding factors, corneal ulcer-related endophthalmitis, endogenous endophthalmitis and initial visual acuity were the independent risk factors for evisceration or enucleation. PMID:27302573

  4. SELF- ENUCLEATION OF EYES IN SCHIZOPHRENIA- AN UNUSUAL MODE OF DELIBERATE SELF HARM

    PubMed Central

    Kumar, P.N. Suresh; Subramanian, N.; Koyamu, A.M. Kunchi; Kumar, Ranja

    2001-01-01

    Self inflicted injury to the eyes including self-enucleation is a rare phenomenon. The authors describe a case of bilateral self-enucleation in a patient with paranoid schizophrenia. A review of literature shows that self-enucleation is correlated with moral, religious and psychodynamic paradigms and various unconscious mechanisms have been proposed to explain this unusual behaviour. PMID:21407887

  5. Undergoing enucleation of the eye. Part 2: postoperative care.

    PubMed

    Cooper, John

    In this, the second of a 2-part article, the author discusses the postoperative care of patients who undergo enucleation of the eye. Part one explored aspects of preoperative care of enucleated patients. In the immediate period following surgery, patients require support and advice regarding pain, nausea and simple care of the eye socket. Apart from the intrinsic postoperative demands of the surgery, there are also the difficulties and challenges associated with providing psychological support and helping patients cope with the loss of an eye. Ultimately, the patient can overcome any initial problems and eventually be able to wear a custom-made prosthesis, which will hopefully allow the patient to move on with their lives. As in the first part, the author will use both referenced material and anecdotal references (upon personal reflection) to analyze the ongoing postoperative care and support of these patients.

  6. Radical resection and enucleation in Chinese adolescents with pancreatic tumors

    PubMed Central

    Yao, Lie; Xie, Zhi-Bo; Jin, Chen; Jiang, Yong-Jian; Li, Ji; Yang, Feng; Lin, Quan-Jun; Fu, De-Liang

    2017-01-01

    Abstract Pancreatic tumors rarely occur in adolescents, and the appropriateness of radical resection for these patients remains controversial. Medical records were retrospectively reviewed for patients younger than 19 years who underwent radical resection or limited resection (enucleation) between 2000 and 2015. Patient demographics, clinical characteristics, operative details, growth, and survival were analyzed. During the study period, 11 adolescents (mean age, 16.18 years; standard deviation, 1.99; interquartile range, 15.0–18.0) underwent radical resection (n = 7) or enucleation (n = 4) to treat solid pseudopapillary tumors (n = 5), pancreatic neuroendocrine tumors (n = 5), or pancreatic ductal adenocarcinoma (n = 1). None of the 7 patients who underwent radical resection experienced recurrence or serious complications, while 3 of 4 patients who underwent enucleation experienced recurrence (P = 0.02). Recurrence-free survival was slightly longer in patients who underwent radical resection, and this procedure did not appear to affect adolescent growth and development. Radical resection might be safe and effective for adolescents with pancreatic tumors. PMID:28328854

  7. The risk of enucleation after proton beam irradiation of uveal melanoma

    SciTech Connect

    Egan, K.M.; Gragoudas, E.S.; Seddon, J.M.; Glynn, R.J.; Munzenreider, J.E.; Goitein, M.; Verhey, L.; Urie, M.; Koehler, A. )

    1989-09-01

    Enucleation after proton beam irradiation of uveal melanomas occurred in 64 (6.4%) of 994 eyes with a median follow-up time of 2.7 years. The median time between irradiation and enucleation in the 64 enucleated eyes was 13 months. The probability of retaining the eye was 95 and 90%, 2 and 5 years postirradiation, respectively. Three percent of eyes were enucleated during posttreatment year 1, and the yearly rate was 1% by the fourth year. No patient had enucleation later than 5 1/2 years posttreatment. The complication most likely to result in enucleation was neovascular glaucoma although this was frequently managed without enucleation. Other common reasons for enucleation were documented or suspected tumor growth and complete retinal detachment with associated loss of vision. The leading risk factors for enucleation were anterior tumor margin involving the ciliary body, tumor height greater than 8 mm, and proximity of the tumor to the fovea. Based on the presence or absence of these factors, 5-year eye retention rates were 99, 92, and 76% for low-, moderate-, and high-risk groups, respectively. Thus, the probability of eye retention after proton beam irradiation is high even among those at greatest risk of enucleation.

  8. New insights into the mechanisms of mammalian erythroid chromatin condensation and enucleation.

    PubMed

    Ji, Peng

    2015-01-01

    A unique feature in mammalian erythropoiesis is the dramatic chromatin condensation followed by enucleation. This step-by-step process starts at the beginning of terminal erythropoiesis after the hematopoietic stem cells are committed to erythroid lineage. Although this phenomenon is known for decades, the mechanisms of chromatin condensation and enucleation remain elusive. Recent advances in cell and molecular biology have started to reveal the molecular pathways in the regulation of chromatin condensation, the establishment of nuclear polarity prior enucleation, and the rearrangement of actin cytoskeleton in enucleation. However, many challenging questions, especially whether and how the apoptotic mechanisms are involved in chromatin condensation and how to dissect the functions of many actin cytoskeleton proteins in cytokinesis and enucleation, remain to be answered. Here I review our current understanding of mammalian erythroid chromatin condensation and enucleation during terminal differentiation with a focus on more recent studies. I conclude with my perspective of future works in this rising topic in developmental and cell biology.

  9. Self-enucleation: forget Freud and Oedipus, it's all about untreated psychosis.

    PubMed

    Large, Matthew Michael; Nielssen, Olav B

    2012-08-01

    Self-enucleation is a rare but serious ophthalmological and psychiatric emergency. It has traditionally been considered to be the result of psycho-sexual conflicts, including those arising from Freud's Oedipal complex and Christian religious teaching. However, an analysis of published case reports suggests that self-enucleation is a result of psychotic illnesses such as schizophrenia. Early treatment with antipsychotic medication in the case of unilateral or threatened self-enucleation might prevent some cases of blindness.

  10. [Enucleation: causes of extrusion of orbital implants (author's transl)].

    PubMed

    Hanselmayer, H; Ritzinger, I

    1978-02-01

    The frequency and the causes of extrusion of orbital implants have been investigated. Of the 294 patients in which enucleation was done, in 17 cases (5.8%) extrusion of the first implant developed; in 9 cases with second or third implantations another 5 implants have been extruded. The extrusion of implants is caused mainly by the operative technique and only rarely by intolerance reactions. For a reliable healing exact sutures of the muscles and also exact closure of the implant with plenty of covering tissue is important.

  11. Video-assisted thoracoscopic enucleation after congenital cardiac surgery

    PubMed Central

    Maeda, Hideyuki; Kanzaki, Masato; Isaka, Tamami; Onuki, Takamasa

    2015-01-01

    A 26-year-old man underwent arterial switch surgery for transposition of the great arteries in infancy. During a routine evaluation, a nodule was detected in the left lower lobe on chest computed tomography. The tumor had enlarged at follow-up and he underwent surgical resection. Because of past cardiac surgery, the pericardium was defective; therefore, the heart was exposed to the pleural cavity and severe adhesions surrounding the left lung. We had to encircle the left main pulmonary artery to perform enucleation safely. The tumor was diagnosed as a pulmonary sclerosing hemangioma using permanent pathology results. PMID:26385193

  12. Enucleation of cultured mouse fetal erythroblasts requires Rac GTPases and mDia2.

    PubMed

    Ji, Peng; Jayapal, Senthil Raja; Lodish, Harvey F

    2008-03-01

    Mammalian erythroid cells undergo enucleation, an asymmetric cell division involving extrusion of a pycnotic nucleus enveloped by the plasma membrane. The mechanisms that power and regulate the enucleation process have remained obscure. Here, we show that deregulation of Rac GTPase during a late stage of erythropoiesis completely blocks enucleation of cultured mouse fetal erythroblasts without affecting their proliferation or differentiation. Formation of the contractile actin ring (CAR) on the plasma membrane of enucleating erythroblasts was disrupted by inhibition of Rac GTPases. Furthermore, we demonstrate that mDia2, a downstream effector of Rho GTPases and a formin protein required for nucleation of unbranched actin filaments, is also required for enucleation of mouse fetal erythroblasts. We show that Rac1 and Rac2 bind to mDia2 in a GTP-dependent manner and that downregulation of mDia2, but not mDia1, by small interfering RNA (siRNA) during the late stages of erythropoiesis blocked both CAR formation and erythroblast enucleation. Additionally, overexpression of a constitutively active mutant of mDia2 rescued the enucleation defects induced by the inhibition of Rac GTPases. These results reveal important roles for Rac GTPases and their effector mDia2 in enucleation of mammalian erythroblasts.

  13. Late onset muscle plasticity in the whisker pad of enucleated rats.

    PubMed

    Toscano-Márquez, Brenda; Martínez-Martínez, Eduardo; Manjarrez, Elías; Martínez, Lourdes; Mendoza-Torreblanca, Julieta; Gutiérrez-Ospina, Gabriel

    2008-10-14

    Blindness leads to a major reorganization of neural pathways associated with touch. Because incoming somatosensory information influences motor output, it is plausible that motor plasticity occurs in the blind. In this work, we evaluated this issue at the peripheral level in enucleated rats. Whisker muscles in enucleated rats 160 days of age or older showed increased cytochrome oxidase activity, capillary density, motor plate size, and amplitude of evoked field potentials as compared with their control counterparts. Such differences were not observed at ages 10 and 60 days, the capillary density was the exception being greater in the enucleated rat at the latter age. Interestingly, there was a trend to increased neurotrophin-3 concentrations in the whisker pads of enucleated rats throughout postnatal development. Our results show that neonatal enucleation leads to late onset plasticity of the whisker's motor system.

  14. Symptomatic subserosal gastric lipoma successfully treated with enucleation.

    PubMed

    Krasniqi, Avdyl-Selmon; Hoxha, Faton-Tatil; Bicaj, Besnik-Xhafer; Hashani, Shemsedin-Isuf; Hasimja, Shpresa-Mehmet; Kelmendi, Sadik-Mal; Gashi-Luci, Lumturije-Hasan

    2008-10-14

    Gastric lipomas are rare tumors, accounting for 2%-3% of all benign gastric tumors. They are of submucosal or extremely rare subserosal origin. Although most gastric lipomas are usually detected incidentally, they can cause abdominal pain, dyspeptic disorders, obstruction, invagination, and hemorrhages. Subserosal gastric lipomas are rarely symptomatic. There is no report on treatment of subserosal gastric lipomas in the English literature. We present a case of a 50-year-old male with symptomatic subserosal gastric lipoma which was successfully managed with removal, enucleation of lipoma, explorative gastrotomy and edge resection for histology check of gastric wall. The incidence of gastric lipoma, advanced diagnostic possibilities and their role in treatment modalities are discussed.

  15. The eyeball killer: serial killings with postmortem globe enucleation.

    PubMed

    Coyle, Julie; Ross, Karen F; Barnard, Jeffrey J; Peacock, Elizabeth; Linch, Charles A; Prahlow, Joseph A

    2015-05-01

    Although serial killings are relatively rare, they can be the cause of a great deal of anxiety while the killer remains at-large. Despite the fact that the motivations for serial killings are typically quite complex, the psychological analysis of a serial killer can provide valuable insight into how and why certain individuals become serial killers. Such knowledge may be instrumental in preventing future serial killings or in solving ongoing cases. In certain serial killings, the various incidents have a variety of similar features. Identification of similarities between separate homicidal incidents is necessary to recognize that a serial killer may be actively killing. In this report, the authors present a group of serial killings involving three prostitutes who were shot to death over a 3-month period. Scene and autopsy findings, including the unusual finding of postmortem enucleation of the eyes, led investigators to recognize the serial nature of the homicides.

  16. Enucleation and development of cluster headache: a retrospective study

    PubMed Central

    Sörös, Peter; Vo, Oanh; Gerding, Heinrich; Husstedt, Ingo W; Evers, Stefan

    2005-01-01

    Background Cluster headache (CH) is a neurovascular, primary headache disorder. There are, however, several case reports about patients whose CH started shortly after a structural brain disease or trauma. Motivated by a patient who developed CH 3 weeks after the removal of an eye and by similar case reports, we tested the hypothesis that the removal of an eye is a risk factor for CH. Methods A detailed headache questionnaire was filled out by 112 patients on average 8 years after enucleation or evisceration of an eye. Results While 21 % of these patients experienced previously unknown headaches after the removal of an eye, no patient fulfilled the diagnostic criteria for CH. Conclusion Our data does not suggest that the removal of an eye is a major risk factor for the development of CH. PMID:15784136

  17. Discharge and infection in retinoblastoma post-enucleation sockets

    PubMed Central

    Mourits, Daphne L; Hartong, Dyonne T; Budding, Andries E; Bosscha, Machteld I; Tan, H Stevie; Moll, Annette C

    2017-01-01

    Purpose To investigate the causes and treatment options for socket discharge and infection in patients enucleated for retinoblastoma (Rb). Methods A questionnaire was filled out by (parents of) ocular prosthesis-wearing patients with a history of enucleation as treatment for Rb. We collected data on patients’ characteristics, cleaning habits of the prosthesis, frequency of socket irritation, discharge, and infection, and use of antibiotics. With ordinal logistic regression analysis, factors related to the outcome parameters (frequency of irritation, mucoid and purulent discharge) were identified. In a subset of young asymptomatic and symptomatic patients, a swab culture of the socket was performed to determine the presence of microorganisms. Results A total of 186 patients or their parents (mean age of the patients: 17.3 years, ranging from 0.8 to 88.3 years) filled out the questionnaire. Irritation, mucoid discharge, and purulent discharge were frequently (once a month or more often) experienced in 75 (39.5%), 127 (66.8%), and 15 (13.2%) sockets, respectively. Younger age was associated with a higher frequency of mucoid and purulent discharge. Radiation therapy, chemotherapy, gender, age at surgery, cleaning frequency, and nocturnal wear were not associated with the outcome parameters. In a subgroup of 26 patients, the sockets were swabbed and cultured. All symptomatic patients had a positive bacterial culture versus 15% (2/13) of the asymptomatic patients (P<0.001). Common cold was correlated with both symptoms and presence of bacteria. Haemophilus influenzae and Staphylococcus aureus were the species most frequently cultured. Conclusion Ocular prosthesis-wearing patients often experienced mucoid discharge, and less often irritation and socket infection. These complaints were found to decrease with increasing age, but did not seem to be influenced by cleaning or wearing habits. Symptomatic sockets, with and without discharge, were correlated with the presence

  18. Demecolcine effects on microtubule kinetics and on chemically assisted enucleation of bovine oocytes.

    PubMed

    Saraiva, Naiara Zoccal; Perecin, Felipe; Méo, Simone Cristina; Ferreira, Christina Ramires; Tetzner, Tatiane Almeida Drummond; Garcia, Joaquim Mansano

    2009-03-01

    This study aimed to evaluate the effect of demecolcine, a microtubule-depolymerizing agent, on microtubule kinetics; to determine the best concentration of demecolcine as a chemically assisted enucleation agent in metaphase I (MI) and metaphase II (MII) bovine oocytes, and to evaluate the embryonic development after nuclear transfer (NT) using chemically assisted enucleation of recipient oocytes. Oocytes in vitro matured for 12 h (MI) and 21 h (MII) were exposed to several concentrations of demecolcine and evaluated for enucleation or membrane protrusion formation. Demecolcine concentration of 0.05 microg/mL produced the highest rates of enucleation in group MI (15.2%) and protrusion formation in group MII (55.1%), and was employed in the following experiments. Demecolcine effect was seen as early as 0.5 h after treatment, with a significant increase in the frequency of oocytes with complete microtubule depletion in MI (58.9%) and MII (21.8%) compared to initial averages at 0 h (27.4% and 1.9%, respectively). Microtubule repolymerization was observed when MII-treated oocytes were cultured in demecolcine-free medium for 6 h (42.4% oocytes with two evident sets of microtubules). Chemically assisted enucleated oocytes were used as recipient cytoplasts in NT procedures to assess embryonic development. For NT, 219 of 515 oocytes (42.5%) formed protrusions and were enucleated, and reconstructed, resulting in 58 nuclear-transferred one-cell embryos. Cleavage (84.5%) and blastocyst development (27.6%) rates were assessed. In conclusion, demecolcine can be used at lower concentrations than routinely employed, and the chemically assisted enucleation technique was proven to be highly efficient allowing embryonic development in bovine.

  19. Increased cortical surface area and gyrification following long-term survival from early monocular enucleation

    PubMed Central

    Kelly, Krista R.; DeSimone, Kevin D.; Gallie, Brenda L.; Steeves, Jennifer K.E.

    2014-01-01

    Purpose Retinoblastoma is typically diagnosed before 5 years of age and is often treated by enucleation (surgical removal) of the cancerous eye. Here, we sought to characterize morphological changes of the cortex following long-term survival from early monocular enucleation. Methods Nine adults with early right-eye enucleation (≤48 months of age) due to retinoblastoma were compared to 18 binocularly intact controls. Surface area, cortical thickness, and gyrification estimates were obtained from T1 weighted images and group differences were examined. Results Early monocular enucleation was associated with increased surface area and/or gyrification in visual (i.e., V1, inferior temporal), auditory (i.e., supramarginal), and multisensory (i.e., superior temporal, inferior parietal, superior parietal) cortices compared with controls. Visual cortex increases were restricted to the right hemisphere contralateral to the remaining eye, consistent with previous subcortical data showing asymmetrical lateral geniculate nucleus volume following early monocular enucleation. Conclusions Altered morphological development of visual, auditory, and multisensory regions occurs subsequent to long-time survival from early eye loss. PMID:25610793

  20. Plant development. Arabidopsis NAC45/86 direct sieve element morphogenesis culminating in enucleation.

    PubMed

    Furuta, Kaori Miyashima; Yadav, Shri Ram; Lehesranta, Satu; Belevich, Ilya; Miyashima, Shunsuke; Heo, Jung-ok; Vatén, Anne; Lindgren, Ove; De Rybel, Bert; Van Isterdael, Gert; Somervuo, Panu; Lichtenberger, Raffael; Rocha, Raquel; Thitamadee, Siripong; Tähtiharju, Sari; Auvinen, Petri; Beeckman, Tom; Jokitalo, Eija; Helariutta, Ykä

    2014-08-22

    Photoassimilates such as sugars are transported through phloem sieve element cells in plants. Adapted for effective transport, sieve elements develop as enucleated living cells. We used electron microscope imaging and three-dimensional reconstruction to follow sieve element morphogenesis in Arabidopsis. We show that sieve element differentiation involves enucleation, in which the nuclear contents are released and degraded in the cytoplasm at the same time as other organelles are rearranged and the cytosol is degraded. These cellular reorganizations are orchestrated by the genetically redundant NAC domain-containing transcription factors, NAC45 and NAC86 (NAC45/86). Among the NAC45/86 targets, we identified a family of genes required for enucleation that encode proteins with nuclease domains. Thus, sieve elements differentiate through a specialized autolysis mechanism.

  1. Rapid Changes in Cortical and Subcortical Brain Regions after Early Bilateral Enucleation in the Mouse

    PubMed Central

    Huffman, Kelly J.

    2015-01-01

    Functional sensory and motor areas in the developing mammalian neocortex are formed through a complex interaction of cortically intrinsic mechanisms, such as gene expression, and cortically extrinsic mechanisms such as those mediated by thalamic input from the senses. Both intrinsic and extrinsic mechanisms are believed to be involved in cortical patterning and the establishment of areal boundaries in early development; however, the nature of the interaction between intrinsic and extrinsic processes is not well understood. In a previous study, we used a perinatal bilateral enucleation mouse model to test some aspects of this interaction by reweighting sensory input to the developing cortex. Visual deprivation at birth resulted in a shift of intraneocortical connections (INCs) that aligned with ectopic ephrin A5 expression in the same location ten days later at postnatal day (P) 10. A prevailing question remained: Does visual deprivation first induce a change in gene expression, followed by a shift in INCs, or vice versa? In the present study, we address this question by investigating the neuroanatomy and patterns of gene expression in post-natal day (P) 1 and 4 mice following bilateral enucleation at birth. Our results demonstrate a rapid reduction in dorsal lateral geniculate nucleus (dLGN) size and ephrin A5 gene expression 24-hours post-enucleation, with more profound effects apparent at P4. The reduced nuclear size and diminished gene expression mirrors subtle changes in ephrin A5 expression evident in P1 and P4 enucleated neocortex, 11 and 8 days prior to natural eye opening, respectively. Somatosensory and visual INCs were indistinguishable between P1 and P4 mice bilaterally enucleated at birth, indicating that perinatal bilateral enucleation initiates a rapid change in gene expression (within one day) followed by an alteration of sensory INCs later on (second postnatal week). With these results, we gain a deeper understanding of how gene expression and

  2. Study of the efficiency of chemically assisted enucleation method for handmade cloning in goat (Capra hircus).

    PubMed

    Akshey, Y S; Malakar, D; De, A K; Jena, M K; Sahu, S; Dutta, R

    2011-08-01

    The present investigation was carried out to find an efficient chemically assisted procedure for enucleation of goat oocytes related to handmade cloning (HMC) technique. After 22-h in vitro maturation, oocytes were incubated with 0.5 μg/ml demecolcine for 2 h. Cumulus cells were removed by pipetting and vortexing in 0.5 mg/ml hyaluronidase, and zona pellucida were digested with pronase. Oocytes with extrusion cones were subjected to oriented bisection. One-third of the cytoplasm with the extrusion cone was removed with a micro blade. The remaining cytoplasts were used as recipients in HMC. Goat foetal fibroblasts were used as nuclear donors. The overall efficiency measured as the number of cytoplasts obtained per total number of oocytes used was significantly (p < 0.05) higher in chemically assisted handmade enucleation (CAHE) than oriented handmade enucleation without demecolcine (OHE) (80.02 ± 1.292% vs. 72.9 ± 1.00%, respectively, mean ± SEM). The reconstructed and activated embryos were cultured in embryo development medium (EDM) for 7 days. Fusion, cleavage and blastocyst development rate were 71.63 ± 1.95%, 92.94 ± 0.91% and 23.78 ± 3.33% (mean ± SEM), respectively which did not differ significantly from those achieved with random handmade enucleation and OHE. In conclusion, chemically assisted enucleation is a highly efficient and reliable enucleation method for goat HMC which eliminates the need of expensive equipment (inverted fluorescence microscope) and potentially harmful chromatin staining and ultraviolet (UV) irradiation for cytoplast selection.

  3. Uveal Melanoma Recurrence After Fractionated Proton Beam Therapy: Comparison of Survival in Patients Treated With Reirradiation or With Enucleation

    SciTech Connect

    Marucci, Laura; Ancukiewicz, Marek; Lane, Anne Marie; Collier, John M.; Gragoudas, Evangelos S.; Munzenrider, John E.

    2011-03-01

    Purpose: To retrospectively compare survival in recurrent uveal melanoma, between patients treated by enucleation or by a second course of fractionated proton beam therapy (PBT). Methods and Materials: Tumor recurrence was documented in 73 patients treated with PBT for uveal melanoma. Of the patients, 31 received a second course of PBT and 42 underwent enucleation. The mean patient age was 56 and 61 years for those undergoing enucleation and those undergoing reirradiation, respectively. Both primary and recurrent tumors were larger in patients undergoing enucleation. Tumor location and the presence or absence of ciliary body involvement did not differ significantly between the groups. The median follow-up after enucleation and after re-treatment was 79 and 59 months, respectively. Cumulative rates of outcomes and differences in rates between the reirradiated and enucleation groups were calculated by the Cox proportional hazards model and the log-rank test, respectively. Results: The median survival duration in the enucleated and reirradiated groups was 42 and 90 months, respectively. The median time free of metastases was 38 months in enucleated patients and 97 months in reirradiated patients. At 5 years after enucleation and after reirradiation, the probability of overall survival was 36% and 63%, respectively (p = 0.040, log-rank test); the probability of freedom from metastases was 31% and 66%, respectively (p = 0.028, log-rank test). These differences persisted after adjustment for recurrent tumor largest diameter and volume at the time of reirradiation or enucleation. Conclusions: This retrospective analysis suggests that survival in reirradiated patients is not compromised by administration of a second course of PBT for recurrent uveal melanoma.

  4. Prevention of Evisceration or Enucleation in Endogenous Bacterial Panophthalmitis with No Light Perception and Scleral Abscess

    PubMed Central

    Chen, Kuan-Jen; Chen, Yen-Po; Chao, An-Ning; Wang, Nan-Kai; Wu, Wei-Chi; Lai, Chi-Chun; Chen, Tun-Lu

    2017-01-01

    Panophthalmitis is the most extensive ocular involvement in endophthalmitis with inflammation in periocular tissues. Severe inflammation of the anterior and posterior segments is frequently accompanied by corneal opacity, scleral abscess, and perforation or rupture. Enucleation or evisceration was the only remaining viable treatment option when all options to salvage the eye had been exhausted. The purpose of this retrospective study is to examine the outcomes of patients with endogenous bacterial panophthalmitis, no light perception and scleral abscess who were treated with multiple intravitreal and periocular injections of antibiotics and dexamethasone. Evaluation included spreading of infection to contiguous or remote sites, following evisceration or enucleation, and sympathetic ophthalmia. Eighteen patients were diagnosed with EBP, with liver abscesses in eight patients, retroperitoneal infection in four, pneumonia in two, infective endocarditis in one, cellulitis in one, drug abuse in one, and mycotic pseudoaneurysm in one. Culture results were positive for Klebsiella pneumoniae in 12 patients, Streptococcus spp. in three, Pseudomonas aeruginosa in one, Escherichia coli in one, and Staphylococcus aureus in one. The average number of periocular injections was 2.2, and the average number of intravitreal injections was 5.8. No eye required evisceration or enucleation and developed the spreading of infection to contiguous or remote sites during the follow-up. No sympathetic ophthalmia was observed in the fellow eye of all patients. Prevention of evisceration or enucleation in patients with EBP, NLP and scleral abscess can be achieved by multiple intravitreal and periocular injections of antibiotics and dexamethasone. PMID:28056067

  5. Establishment of Immortalized Human Erythroid Progenitor Cell Lines Able to Produce Enucleated Red Blood Cells

    PubMed Central

    Kurita, Ryo; Suda, Noriko; Sudo, Kazuhiro; Miharada, Kenichi; Hiroyama, Takashi; Miyoshi, Hiroyuki; Tani, Kenzaburo; Nakamura, Yukio

    2013-01-01

    Transfusion of red blood cells (RBCs) is a standard and indispensable therapy in current clinical practice. In vitro production of RBCs offers a potential means to overcome a shortage of transfusable RBCs in some clinical situations and also to provide a source of cells free from possible infection or contamination by microorganisms. Thus, in vitro production of RBCs may become a standard procedure in the future. We previously reported the successful establishment of immortalized mouse erythroid progenitor cell lines that were able to produce mature RBCs very efficiently. Here, we have developed a reliable protocol for establishing immortalized human erythroid progenitor cell lines that are able to produce enucleated RBCs. These immortalized cell lines produce functional hemoglobin and express erythroid-specific markers, and these markers are upregulated following induction of differentiation in vitro. Most importantly, these immortalized cell lines all produce enucleated RBCs after induction of differentiation in vitro, although the efficiency of producing enucleated RBCs remains to be improved further. To the best of our knowledge, this is the first demonstration of the feasibility of using immortalized human erythroid progenitor cell lines as an ex vivo source for production of enucleated RBCs. PMID:23533656

  6. Lasers.

    ERIC Educational Resources Information Center

    Schewe, Phillip F.

    1981-01-01

    Examines the nature of laser light. Topics include: (1) production and characteristics of laser light; (2) nine types of lasers; (3) five laser techniques including holography; (4) laser spectroscopy; and (5) laser fusion and other applications. (SK)

  7. Novel methylene blue staining technique for localizing small esophageal leiomyomas during thoracoscopic enucleation.

    PubMed

    Zhang, Z; Ai, B; Liao, Y; Liu, L; Liu, M

    2016-11-01

    The treatment of choice for leiomyoma, the most common benign esophageal tumor, is thoracoscopic enucleation. One of the most difficult aspects of thoracoscopic enucleation is the precise localization of small tumors (≤1.5 cm) and tumors without external protrusion. No simple, feasible solutions to this problem are available. We developed a novel methylene blue staining technique to localize small esophageal leiomyomas and evaluated the feasibility of our technique. Between January 2013 and July 2014, eight patients with small esophageal leiomyomas (≤1.5 cm) underwent thoracoscopic enucleation in Tongji Hospital. Preoperative endoscopic ultrasonography was performed in all patients. The leiomyomas were located in the middle (n = 5) and lower (n = 3) thirds of the esophagus. We preoperatively injected 0.5-1.0 mL methylene blue in the submucosa adjacent to the tumors under standard gastroscope guidance. The entire staining process took about 10 minutes. Staining was successful in all patients. The unstained tumor was exposed after the blue-stained mediastinal pleura, and overlying muscle were incised longitudinally. All procedures were successfully completed without conversion to open surgery. No abnormalities were detected in the esophageal mucosa. The median operating time was 60 minutes (range, 40-90 minutes). Postoperative histopathology confirmed leiomyoma in all patients. The median postoperative hospital stay was 6 days (range, 5-7 days). No major complications, such as esophageal leakage or esophageal diverticulum, occurred. Endoscopic methylene blue staining is safe and feasible for localizing small esophageal leiomyomas during thoracoscopic enucleation. This method will enable precise and easy enucleation.

  8. Ophthalmomyiasis caused by a Phormia sp. (Diptera: Calliphoridae) larva in an enucleated patient.

    PubMed

    Kim, Jae-Soo; Kim, Jong-Wan; Lee, Hye-Jung; Lee, In-Yong; Oh, Sang-Ah; Seo, Min

    2011-06-01

    Ophthalmomyiasis rarely occurs worldwide, and has not been reported in Korea. We present here a case of ophthalmomyiasis caused by Phormia sp. fly larva in an enucleated eye of a patient. In June 2010, a 50-year-old man was admitted to Dankook University Hospital for surgical excision of a malignant melanoma located in the right auricular area. He had a clinical history of enucleation of his right eye due to squamous cell carcinoma 5 years ago. During hospitalization, foreign body sensation developed in his right eye, and close examination revealed a fly larva inside the eye, which was evacuated. The larva was proved to be Phormia sp. based on the morphology of the posterior spiracle. Subsequently, no larva was found, and the postoperative course was uneventful without any complaints of further myiasis. This is the first case of ophthalmomyiasis among the literature in Korea, and also the first myiasis case caused by Phormia sp. in Korea.

  9. Nuclear transfer of embryonic cell nuclei to non-enucleated eggs in zebrafish, Danio rerio.

    PubMed

    Hattori, Manabu; Hashimoto, Hisashi; Bubenshchikova, Ekaterina; Wakamatsu, Yuko

    2011-04-15

    We previously established a novel method for nuclear transfer in medaka (Oryzias latipes) using non-enucleated, diploidized eggs as recipients for adult somatic cell nuclei. Here we report the first attempt to apply this method to another fish species. To examine suitability of using non-enucleated eggs as recipients for nuclear transfer in the zebrafish (Danio rerio), we transferred blastula cell nuclei from a wild-type donor strain to non-enucleated, unfertilized eggs from a golden recipient strain. As a result, 31 of 184 (16.8%) operated eggs developed normally and reached the adult stage. Twenty-eight (15.2%) of these transplants showed wild-type phenotype and the remaining three (1.6%) were golden. Except for one individual that exhibited diploid/tetraploid mosaicism, all of the wild-type nuclear transplants were either triploid or diploid. While all of 19 triploid transplants were infertile, a total of six transplants (21.4%) were fertile (five of the eight diploid transplants and one transplant exhibiting ploidy mosaicism). Except for one diploid individual, all of the fertile transplants transferred both the wild-type golden gene allele (slc24a5) as well as the phenotype, the wild-type body color, to their F(1) and F(2) progeny in a typical Mendelian fashion. PCR analysis of slc24a5 suggested that triploidy originated from a fused nucleus in the diploid donor and haploid recipient nuclei, and that the sole origin of diploidy was the diploid donor nucleus. The results of the present study demonstrated the suitability of using non-enucleated eggs as recipients for nuclear transfer experiments in zebrafish.

  10. Impediments to eye transplantation: ocular viability following optic-nerve transection or enucleation.

    PubMed

    Ellenberg, D; Shi, J; Jain, S; Chang, J-H; Ripps, H; Brady, S; Melhem, E R; Lakkis, F; Adamis, A; Chen, D-F; Ellis-Behnke, R; Langer, R S; Strittmatter, S M; Azar, D T

    2009-09-01

    Maintenance of ocular viability is one of the major impediments to successful whole-eye transplantation. This review provides a comprehensive understanding of the current literature to help guide future studies in order to overcome this hurdle. A systematic multistage review of published literature was performed. Three specific questions were addressed: (1) Is recovery of visual function following eye transplantation greater in cold-blooded vertebrates when compared with mammals? (2) Is outer retina function following enucleation and reperfusion improved compared with enucleation alone? (3) Following optic-nerve transection, is there a correlation between retinal ganglion cell (RGC) survival and either time after transection or proximity of the transection to the globe? In a majority of the studies performed in the literature, recovery of visual function can occur after whole-eye transplantation in cold-blooded vertebrates. Following enucleation (and reperfusion), outer retinal function is maintained from 4 to 9 h. RGC survival following optic-nerve transection is inversely related to both the time since transection and the proximity of transection to the globe. Lastly, neurotrophins can increase RGC survival following optic-nerve transection. This review of the literature suggests that the use of a donor eye is feasible for whole-eye transplantation.

  11. Le Fort I osteotomy to enucleation of grand proportions fissural cyst-presentation of case report.

    PubMed

    Cavalcante, Rafael Correia; Durski, Fernanda; Deliberador, Tatiana Miranda; Giovanini, Allan Fernando; Rebellato, Nelson Luís Barbosa; da Costa, Delson João; Klüppel, Leandro Eduardo; Scariot, Rafaela

    2016-01-01

    Fissural cysts (FC) are caused by entraped epithelium between nasal and maxilar processes. They are commonly treated with surgical enucleation precedded or not by marsupialization depending on the cyst size. Biopsy of lesion is recommended due to confirm radiographic evaluation. It is rare to observe Le Fort I surgical approach to this type of injury. This study reports the case of an uncommon grand proportions fissural cyst in a female patient, 53, that was referred to the Oral and Maxillofacial Surgery Departament of Hospital XV presenting volume increase in maxilla associated with numbness of palate. Radiograph examination showed an intimate relationship between incisors apexes and FC. Expansion of both buccal and palate cortical was then confirmed as well as its unusual size, approximately 25 millimeters. Due to the abnormal size of lesion and possible impairment of upper incisors, LeFort I osteotomy associated with downfracture to cystic enucleation was the chosen treatment. After enucleation, the remaining space was filled with BIOSs and bioguide (lyophilized bone and collagen membrane). Patients' twelve months follow-up demonstrate no relapses and maintenance of teeth involved.

  12. Three histopathological types of retinoblastoma and their relation to heredity and age of enucleation.

    PubMed

    Moll, A C; Koten, J W; Lindenmayer, D A; Everse, L A; Tan, K E; Hamburg, A; Faber, J A; Den Otter, W

    1996-11-01

    The histopathology of 61 eyes was studied with special attention to the morphology of the retina adjacent to the main tumour. Three retinal types were distinguished. Retina type 1 (RT-1, 28 specimens) contained a single tumour that was sharply demarcated from surrounding normal retina. In retina type 2 (RT-2, 29 specimens) large parts of the retina were affected and the main tumour mass gradually blended with the adjacent pathological retina. Retina type 3 (RT-3, four specimens) was characterised by a retina almost entirely affected by diffuse tumour growth. RT-1 correlated significantly with early enucleation (0-3 years) both in hereditary and non-hereditary cases. RT-2 was seen in eyes enucleated later (2-5 years). The progressing tumour may release growth factors in the intraocular space that stimulate the cells of the adjacent retina and lead to multiple new primary tumours in the adjacent retinal area. RT-3 was only present in non-hereditary cases with late enucleation (at 2-5 years). Hereditary retinoblastoma cases are usually detected early. Therefore in hereditary cases RT-1 is significantly more common than RT-2. In 25 eyes of the 44 patients with unilateral sporadic retinoblastoma, multifocal tumours of the retina were observed. Such cases should not mistakenly be classified as hereditary cases on the basis of the histological pattern of multifocality of the tumour process.

  13. Transurethral enucleation of prostate with button electrode plasmakinetic vaporization for the treatment of Benign Prostatic Hyperplasia

    PubMed Central

    Peng, Bo; Huang, Jianhua; Wang, Guangchun; Zhang, Haimin; Liu, Min

    2016-01-01

    Benign prostatic hyperplasia (BPH) is a common disease in aged men. In this study, we investigated the efficacy and safety of transurethral enucleation of prostate with button electrode plasmakinetic vaporization for the treatment of BPH. 60 patients diagnosed with BPH who were treated in our hospital from August to December, 2014 by enucleation with button electrode were retrospectively reviewed, and operation time, urinary catheter indwelling time, continuous bladder irrigation time, operation related complications, maximum urinary flow rate (Qmax), post-void residual urine volume (PVR), International Prostate Symptom Score (IPSS), quality of life assessment (QOL), perioperative hemoglobin and electrolytes were recorded. All the operations were completed successfully. The operation time and urinary catheter indwelling time were 45.3 ± 16.2 min and 1.72 ± 0.32 d, respectively. During the follow-up, urethral stricture (n = 1), and urinary incontinence (n = 2) were found with recovery after 1-month training. Postoperative PVR at 1, 3 and 6 months significantly decreased compared with preoperative ones (P < 0.05). IPSS, Qmax, QOL at 1, 3 and 6 months improved significantly (P < 0.05). There was no significant difference in serum hemoglobin, sodium and potassium before and after the operation. Thus, the study proved that enucleation of prostate with button electrode was efficient and safe, which was worth being recommended. PMID:28008957

  14. Wilbrand's knee of the primate optic chiasm is an artefact of monocular enucleation.

    PubMed Central

    Horton, J C

    1997-01-01

    PURPOSE: The anterior chiasmal syndrome consists of a temporal hemianopia or complete visual field loss in one eye, plus a superior temporal hemianopia in the other eye. The superior temporal hemianopia in the other eye is thought to result from injury to Wilbrand's Knee of the optic chiasm. Wilbrand's Knee is a loop of decussating fibers which detours into the contralateral optic nerve before entering the optic tract. I studied the organization of fibers in the optic chiasm of monkeys and humans to verify the existence of Wilbrand's Knee and to elucidate further the pattern of visual field loss seen from lesions of the sellar region. METHODS: The primary optic pathway was labelled in monkeys by injection of [3H] proline into one eye, followed by autoradiography. There were 8 intact Rhesus monkeys and 3 intact squirrel monkeys. In addition, the optic pathway was studied in the Rhesus monkey 6 months and 4 years after monocular enucleation. The optic chiasm was also examined using myelin stains in specimens obtained post-mortem from 3 patients. The patients had lost 1 eye 5 months, 2 years, and 28 years prior to their deaths. Finally, clinical observations were recorded in 3 patients with the anterior chiasmal syndrome. RESULTS: In normal Rhesus and squirrel monkeys, optic nerve fibers crossed the optic chiasm without entering the contralateral optic nerve. After short-term monocular enucleation, fibers from the normal optic nerve were drawn closer to the entry zone of the degenerating optic nerve, but Wilbrand's Knee was still absent. After long-term enucleation, a typical Wilbrand's Knee was induced to form. In the human, Wilbrand's Knee was absent 5 months after monocular enucleation, but emerged in the two cases involving long-term enucleation, in a fashion analogous to the monkey. The case reports describe 3 patients with variants of the anterior chiasmal syndrome from parasellar tumors. CONCLUSIONS: Wilbrand's Knee does not exist in the normal primate optic

  15. Holmium laser applications of the prostate.

    PubMed

    Lerner, Lori B; Tyson, Mark D

    2009-11-01

    The high-powered holmium laser is an excellent tool for the surgical treatment of benign prostatic hyperplasia. This article discusses the background of holmium use in the prostate and describes the surgical techniques of holmium laser ablation of the prostate and holmium laser enucleation of the prostate. Operative challenges are reviewed with suggestions as to how to avoid these problems or deal with them when they arise. Surgical outcomes and a thorough literature review are both presented.

  16. The combined effects of unilateral enucleation and rearing in a 'dim' red light on synapse-to-neuron ratios in the rat visual cortex.

    PubMed Central

    Bedi, K S

    1989-01-01

    One day old rats had their right eyes removed and together with non-enucleated controls were raised in either 'light' or 'dark' (red light) conditions from birth until 39 days of age. This resulted in four groups of animals: light-reared enucleated, light-reared non-enucleated, dark-reared enucleated and dark-reared non-enucleated. All animals were killed by intracardiac perfusion with 2.5% sodium cacodylate-buffered glutaraldehyde at 39 days of age. Pieces of visual cortex (Area 17) from both right and left cerebral hemispheres of each animal were dissected out and processed for electron microscopy. Stereological procedures were used to estimate the synapse-to-neuron ratios in Layers II-III of these cortices. Light-reared non-enucleated rats had about 16,000 synapses per neuron in both right and left visual cortices. Rearing non-enucleated rats in the dark reduced this value to about 11,500. The synapse-to-neuron ratio of unilaterally enucleated rats raised in the light was not significantly different from that observed in light-reared non-enucleated rats. Combined dark-rearing and unilateral enucleation did reduce the synapse-to-neuron ratio but not to any greater extent than did dark-rearing alone. However, there was a suggestion of a differential effect between the right and left cortices in these enucleated, dark-reared animals. These results demonstrate the importance of light stimulation for the normal development of interneuronal connectivity of the visual cortex. They also show that the effects of unilateral enucleation for the visual cortex are not as great as those previously observed for the superior colliculi in the same animals, at least as far as synapse-to-neuron ratios are concerned. Images Fig. 1 Fig. 2 PMID:2630542

  17. Chemically induced enucleation of activated bovine oocytes: chromatin and microtubule organization and production of viable cytoplasts.

    PubMed

    Saraiva, Naiara Zoccal; Oliveira, Clara Slade; Leal, Cláudia Lima Verde; de Lima, Marina Ragagnin; Del Collado, Maite; Vantini, Roberta; Monteiro, Fabio Morato; Niciura, Simone Cristina Méo; Garcia, Joaquim Mansano

    2015-12-01

    As the standard enucleation method in mammalian nuclear transfer is invasive and damaging to cytoplast spatial organization, alternative procedures have been developed over recent years. Among these techniques, chemically induced enucleation (IE) is especially interesting because it does not employ ultraviolet light and reduces the amount of cytoplasm eliminated during the procedure. The objective of this study was to optimize the culture conditions with demecolcine of pre-activated bovine oocytes for chemically IE, and to evaluate nuclear and microtubule organization in cytoplasts obtained by this technique and their viability. In the first experiment, a negative effect on oocyte activation was verified when demecolcine was added at the beginning of the process, reducing activation rates by approximately 30%. This effect was not observed when demecolcine was added to the medium after 1.5 h of activation. In the second experiment, although a reduction in the number of microtubules was observed in most oocytes, these structures did not disappear completely during assessment. Approximately 50% of treated oocytes presented microtubule reduction at the end of the evaluation period, while 23% of oocytes were observed to exhibit the complete disappearance of these structures and 28% exhibited visible microtubules. These findings indicated the lack of immediate microtubule repolymerization after culture in demecolcine-free medium, a fact that may negatively influence embryonic development. However, cleavage rates of 63.6-70.0% and blastocyst yield of 15.5-24.2% were obtained in the final experiment, without significant differences between techniques, indicating that chemically induced enucleation produces normal embryos.

  18. Lasers for median lobe hyperplasia.

    PubMed

    Muschter, R; Gilling, A P

    2001-08-01

    Laser treatment encompases a variety of techniques using different laser wavelengths, application systems, and surgical techniques to achieve contrasting tissue effects such as incision, resection, vaporization, or coagulation. Many studies have proven the clinical efficacy of the various laser techniques for the treatment of benign prostatiuc hyperplasia, including randomized studies versus transurethral prostatectomy (TURP). Recently, long-term follow-up of up to 5 years has demonstrated the durability of the results, although in some of the studies, retreatment rates were higher than after TURP. Median lobes were never seen as a contraindication for treatment in the laser based procedures. Technically, laser treatment techniques such as side-firing transurethral coagulation, contact- and free-beam laser vaporization, interstitial laser coagulation, and the holmium laser-based resection and enucleation are fully suitable for treatment of median lobes. Surprisingly, no studies focussing specifically on laser treatment of median lobes have been published.

  19. miR-191 regulates mouse erythroblast enucleation by down-regulating Riok3 and Mxi1.

    PubMed

    Zhang, Lingbo; Flygare, Johan; Wong, Piu; Lim, Bing; Lodish, Harvey F

    2011-01-15

    Using RNA-seq technology, we found that the majority of microRNAs (miRNAs) present in CFU-E erythroid progenitors are down-regulated during terminal erythroid differentiation. Of the developmentally down-regulated miRNAs, ectopic overexpression of miR-191 blocks erythroid enucleation but has minor effects on proliferation and differentiation. We identified two erythroid-enriched and developmentally up-regulated genes, Riok3 and Mxi1, as direct targets of miR-191. Knockdown of either Riok3 or Mxi1 blocks enucleation, and either physiological overexpression of miR-191 or knockdown of Riok3 or Mxi1 blocks chromatin condensation. Thus, down-regulation of miR-191 is essential for erythroid chromatin condensation and enucleation by allowing up-regulation of Riok3 and Mxi1.

  20. Hereditary Spherocytosis and Hereditary Elliptocytosis: Aberrant Protein Sorting during Erythroblast Enucleation

    SciTech Connect

    Salomao, Marcela; Chen, Ke; Villalobos, Jonathan; Mohandas, Narla; An, Xiuli; Chasis, Joel Anne

    2010-02-08

    During erythroblast enucleation, membrane proteins distribute between extruded nuclei and reticulocytes. In hereditary spherocytosis (HS) and hereditary elliptocytosis (HE), deficiencies of membrane proteins, in addition to those encoded by the mutant gene, occur. Elliptocytes, resulting from protein 4.1R gene mutations, lack not only 4.1R but also glycophorin C, which links the cytoskeleton and bilayer. In HS resulting from ankyrin-1 mutations, band 3, Rh-associated antigen, and glycophorin A are deficient. The current study was undertaken to explore whether aberrant protein sorting, during enucleation, creates these membrane-spanning protein deficiencies. We found that although glycophorin C sorts to reticulocytes normally, it distributes to nuclei in 4.1R-deficient HE cells. Further, glycophorin A and Rh-associated antigen, which normally partition predominantly to reticulocytes, distribute to both nuclei and reticulocytes in an ankyrin-1-deficient murine model of HS. We conclude that aberrant protein sorting is one mechanistic basis for protein deficiencies in HE and HS.

  1. A chemical enucleation method for the transfer of mitochondrial DNA to rho(o) cells.

    PubMed

    Bayona-Bafaluy, Maria Pilar; Manfredi, Giovanni; Moraes, Carlos T

    2003-08-15

    The study of pathogenic mitochondrial DNA mutations has, in most cases, relied on the production of transmitochondrial cybrids. Although the procedure to produce such cybrids is well established, it is laborious and cumbersome. Moreover, the mechanical enucleation procedure is inefficient and different techniques have to be used depending on the adherence properties of the cell. To circumvent these difficulties, we developed a chemical enucleation method that can have wide applicability for the production of transmitochondrial cybrids. The method is based on the use of actinomycin D to render the nuclear genome transcription/replication inactive and unable to recover after treatment. Such treated cells are fused to cells devoid of mitochondrial DNA and selected for the presence of a functional oxidative phosphorylation system. Our results showed that 95% of the clones recovered by this procedure are true transmitochondrial cybrids. This method greatly facilitates the production of transmitochondrial cybrids, thereby increasing the number of mtDNA mutations and the recipient cell types that can be studied by this system.

  2. Telelap Alf-X-Assisted Laparoscopy for Ovarian Cyst Enucleation: Report of the First 10 Cases.

    PubMed

    Gueli Alletti, Salvatore; Rossitto, Cristiano; Fanfani, Francesco; Fagotti, Anna; Costantini, Barbara; Gidaro, Stefano; Monterossi, Giorgia; Selvaggi, Luigi; Scambia, Giovanni

    2015-01-01

    This prospective single-institutional clinical trial sought to assess the safety and feasibility of laparoscopic benign ovarian cyst enucleation with a novel robotic-assisted laparoscopic system. Here we report a series of 10 patients treated using the Telelap ALF-X system in the first clinical application on patients at the Division of Gynecologic Oncology, Catholic University of the Sacred Heart of Rome. The primary inclusion criterion was the presence of monolateral ovarian cyst without a preoperative assessment suspicious for malignancy. Intraoperative data, including docking time, operative time, estimated blood loss, intraoperative and perioperative complications, and conversion to either standard laparoscopy or laparotomy, were collected. The cysts were removed with an ovary-sparing technique with respect to conservative surgical principles. The median operative time was 46.3 minutes, and patients without postoperative complications were discharged at 1 or 2 days after the procedure. Telelap ALF-X laparoscopic enucleation of benign ovarian cysts with an ovary-sparing technique is feasible, safe, and effective; however, more clinical data are needed to determine whether this approach can offer any other benefits over other minimally invasive surgical techniques.

  3. A technique for evisceration as an alternative to enucleation in birds of prey: 19 cases.

    PubMed

    Murray, Maureen; Pizzirani, Stefano; Tseng, Florina

    2013-06-01

    Ocular trauma is common in birds of prey presented to wildlife clinics and rehabilitation centers. Enucleation is the procedure most commonly described for treatment of end-stage ocular disease or chronically painful eyes in birds; however, there are several disadvantages and risks to this procedure. While evisceration has been suggested as an alternative, it has not been described for multiple cases or with long-term follow-up data in birds of prey. This report details an evisceration technique performed in 5 captive birds of prey of 4 different species (1 eastern screech owl [Megascops asio], 1 great horned owl [Bubo virginianus], 2 red-tailed hawks [Buteo jamaicensis], and 1 bald eagle [Haliaeetus leucocephalus]) with long-term follow-up information. In addition, this report describes 14 cases of free-living owls of 3 different species (1 great horned owl, 4 barred owls [Strix varia], and 9 eastern screech owls) on which this technique was performed from 2004 to 2011 and which were subsequently released to the wild. Because of the limited risk of complications and the less-severe disruption of facial symmetry, which may be particularly important in owls that are candidates for release to the wild, evisceration should be considered over enucleation in birds of prey that require surgical intervention for the management of severe sequelae to ocular trauma.

  4. A simple technique for hemostasis control after enucleation of deep located liver tumors or after liver trauma

    PubMed Central

    Machado, Marcel A.; Surjan, Rodrigo C.; Basseres, Tiago; Makdissi, Fábio F.

    2016-01-01

    Modern liver techniques allowed the development of segment-based anatomical liver resections. Nevertheless, there is still a place for nonanatomical liver resections. However, in some cases, there is a need for enucleation of deep located liver tumors. The main problem with enucleation of a liver tumor deeply located in the middle of the liver is the control of bleeding resulting from the rupture of small or medium vessels. The authors describe a simple way to control the bleeding without the use of any special instrument or material. This technique can also be used to control bleeding from penetrating liver injury. PMID:26846270

  5. The Asymmetric Cell Division Regulators Par3, Scribble and Pins/Gpsm2 Are Not Essential for Erythroid Development or Enucleation

    PubMed Central

    Wölwer, Christina B.; Gödde, Nathan; Pase, Luke B.; Elsum, Imogen A.; Lim, Krystle Y. B.; Sacirbegovic, Faruk; Walkley, Carl R.; Ellis, Sarah; Ohno, Shigeo; Matsuzaki, Fumio; Russell, Sarah M.; Humbert, Patrick O.

    2017-01-01

    Erythroid enucleation is the process by which the future red blood cell disposes of its nucleus prior to entering the blood stream. This key event during red blood cell development has been likened to an asymmetric cell division (ACD), by which the enucleating erythroblast divides into two very different daughter cells of alternate molecular composition, a nucleated cell that will be removed by associated macrophages, and the reticulocyte that will mature to the definitive erythrocyte. Here we investigated gene expression of members of the Par, Scribble and Pins/Gpsm2 asymmetric cell division complexes in erythroid cells, and functionally tested their role in erythroid enucleation in vivo and ex vivo. Despite their roles in regulating ACD in other contexts, we found that these polarity regulators are not essential for erythroid enucleation, nor for erythroid development in vivo. Together our results put into question a role for cell polarity and asymmetric cell division in erythroid enucleation. PMID:28095473

  6. Visual system plasticity in mammals: the story of monocular enucleation-induced vision loss

    PubMed Central

    Nys, Julie; Scheyltjens, Isabelle; Arckens, Lutgarde

    2015-01-01

    The groundbreaking work of Hubel and Wiesel in the 1960’s on ocular dominance plasticity instigated many studies of the visual system of mammals, enriching our understanding of how the development of its structure and function depends on high quality visual input through both eyes. These studies have mainly employed lid suturing, dark rearing and eye patching applied to different species to reduce or impair visual input, and have created extensive knowledge on binocular vision. However, not all aspects and types of plasticity in the visual cortex have been covered in full detail. In that regard, a more drastic deprivation method like enucleation, leading to complete vision loss appears useful as it has more widespread effects on the afferent visual pathway and even on non-visual brain regions. One-eyed vision due to monocular enucleation (ME) profoundly affects the contralateral retinorecipient subcortical and cortical structures thereby creating a powerful means to investigate cortical plasticity phenomena in which binocular competition has no vote.In this review, we will present current knowledge about the specific application of ME as an experimental tool to study visual and cross-modal brain plasticity and compare early postnatal stages up into adulthood. The structural and physiological consequences of this type of extensive sensory loss as documented and studied in several animal species and human patients will be discussed. We will summarize how ME studies have been instrumental to our current understanding of the differentiation of sensory systems and how the structure and function of cortical circuits in mammals are shaped in response to such an extensive alteration in experience. In conclusion, we will highlight future perspectives and the clinical relevance of adding ME to the list of more longstanding deprivation models in visual system research. PMID:25972788

  7. Aqueous Angiography–Mediated Guidance of Trabecular Bypass Improves Angiographic Outflow in Human Enucleated Eyes

    PubMed Central

    Huang, Alex S.; Saraswathy, Sindhu; Dastiridou, Anna; Begian, Alan; Mohindroo, Chirayu; Tan, James C. H.; Francis, Brian A.; Hinton, David R.; Weinreb, Robert N.

    2016-01-01

    Purpose To assess the ability of trabecular micro-bypass stents to improve aqueous humor outflow (AHO) in regions initially devoid of AHO as assessed by aqueous angiography. Methods Enucleated human eyes (14 total from 7 males and 3 females [ages 52–84]) were obtained from an eye bank within 48 hours of death. Eyes were oriented by inferior oblique insertion, and aqueous angiography was performed with indocyanine green (ICG; 0.4%) or fluorescein (2.5%) at 10 mm Hg. With an angiographer, infrared and fluorescent images were acquired. Concurrent anterior segment optical coherence tomography (OCT) was performed, and fixable fluorescent dextrans were introduced into the eye for histologic analysis of angiographically positive and negative areas. Experimentally, some eyes (n = 11) first received ICG aqueous angiography to determine angiographic patterns. These eyes then underwent trabecular micro-bypass sham or stent placement in regions initially devoid of angiographic signal. This was followed by fluorescein aqueous angiography to query the effects. Results Aqueous angiography in human eyes yielded high-quality images with segmental patterns. Distally, angiographically positive but not negative areas demonstrated intrascleral lumens on OCT images. Aqueous angiography with fluorescent dextrans led to their trapping in AHO pathways. Trabecular bypass but not sham in regions initially devoid of ICG aqueous angiography led to increased aqueous angiography as assessed by fluorescein (P = 0.043). Conclusions Using sequential aqueous angiography in an enucleated human eye model system, regions initially without angiographic flow or signal could be recruited for AHO using a trabecular bypass stent. PMID:27588614

  8. Visual system plasticity in mammals: the story of monocular enucleation-induced vision loss.

    PubMed

    Nys, Julie; Scheyltjens, Isabelle; Arckens, Lutgarde

    2015-01-01

    The groundbreaking work of Hubel and Wiesel in the 1960's on ocular dominance plasticity instigated many studies of the visual system of mammals, enriching our understanding of how the development of its structure and function depends on high quality visual input through both eyes. These studies have mainly employed lid suturing, dark rearing and eye patching applied to different species to reduce or impair visual input, and have created extensive knowledge on binocular vision. However, not all aspects and types of plasticity in the visual cortex have been covered in full detail. In that regard, a more drastic deprivation method like enucleation, leading to complete vision loss appears useful as it has more widespread effects on the afferent visual pathway and even on non-visual brain regions. One-eyed vision due to monocular enucleation (ME) profoundly affects the contralateral retinorecipient subcortical and cortical structures thereby creating a powerful means to investigate cortical plasticity phenomena in which binocular competition has no vote.In this review, we will present current knowledge about the specific application of ME as an experimental tool to study visual and cross-modal brain plasticity and compare early postnatal stages up into adulthood. The structural and physiological consequences of this type of extensive sensory loss as documented and studied in several animal species and human patients will be discussed. We will summarize how ME studies have been instrumental to our current understanding of the differentiation of sensory systems and how the structure and function of cortical circuits in mammals are shaped in response to such an extensive alteration in experience. In conclusion, we will highlight future perspectives and the clinical relevance of adding ME to the list of more longstanding deprivation models in visual system research.

  9. Metabolic changes in the nucleus of the optic tract after monocular enucleation as revealed by cytochrome oxidase histochemistry.

    PubMed

    Vargas, C D; Sousa, A O; Santos, C M; Pereira, A; Bernardes, R F; Rocha-Miranda, C E; Volchan, E

    2001-03-01

    The histochemistry for the mitochondrial enzyme cytochrome oxidase (CO) was used to evaluate the levels of metabolic activity in neurons of the nucleus of the optic tract (NOT) and dorsal terminal nucleus (DTN) in the opossum (Didelphis aurita). The observations were performed in four groups: normal juveniles (4 months old), monocularly enucleated juveniles analysed when adults, normal adults (8 to 18 months old) and monocularly enucleated adults. CO labeled cells were observed to have a similar distribution along the NOT-DTN anteroposterior axis in both juvenile and adult normal animals. Monocular enucleation performed in adults produced a significant reduction of the reactive neuropil but not of the number of CO labeled cells in the deafferented NOT-DTN: the number of labeled neurons per section in the deafferented side matched those of the ipsilateral complex. In juveniles, however, this procedure caused a systematic reduction of the number of CO labeled cells in the contralateral NOT-DTN in comparison to the spared complex. The lack of reduction in the number of neurons found on the deafferented side of the NOT-DTN of monocularly enucleated adult opossums compared with the ipsilateral side might result from the presence of compensatory inputs to maintain their metabolic equivalence. However, when the monocular enucleation was performed in juvenile opossums, a statistically significant asymmetry of CO neurons in the NOT-DTN was observed. In other words, the compensatory mechanisms proposed for the adults were either absent or insufficient to achieve symmetry in juveniles, suggesting a more heavily reliance in the retinal input.

  10. Ankyrin and band 3 differentially affect expression of membrane glycoproteins but are not required for erythroblast enucleation.

    PubMed

    Ji, Peng; Lodish, Harvey F

    2012-01-27

    During late stages of mammalian erythropoiesis the nucleus undergoes chromatin condensation, migration to the plasma membrane, and extrusion from the cytoplasm surrounded by a segment of plasma membrane. Since nuclear condensation occurs in all vertebrates, mammalian erythroid membrane and cytoskeleton proteins were implicated as playing important roles in mediating the movement and extrusion of the nucleus. Here we use erythroid ankyrin deficient and band 3 knockout mouse models to show that band 3, but not ankyrin, plays an important role in regulating the level of erythroid cell membrane proteins, as evidenced by decreased cell surface expression of glycophorin A in band 3 knockout mice. However, neither band 3 nor ankyrin are required for enucleation. These results demonstrate that mammalian erythroblast enucleation does not depend on the membrane integrity generated by the ankyrin-band 3 complex.

  11. Shifts in Developmental Timing, and Not Increased Levels of Experience-Dependent Neuronal Activity, Promote Barrel Expansion in the Primary Somatosensory Cortex of Rats Enucleated at Birth

    PubMed Central

    Fetter-Pruneda, Ingrid; Ibarrarán-Viniegra, Ana Sofía; Martínez-Martínez, Eduardo; Sandoval-Velasco, Marcela; Uribe-Figueroa, Laura; Padilla-Cortés, Patricia; Mercado-Célis, Gabriela; Gutiérrez-Ospina, Gabriel

    2013-01-01

    Birth-enucleated rodents display enlarged representations of whiskers (i.e., barrels of the posteromedial subfield) in the primary somatosensory cortex. Although the historical view maintains that barrel expansion is due to incremental increases in neuronal activity along the trigeminal pathway during postnatal development, recent evidence obtained in experimental models of intramodal plasticity challenges this view. Here, we re-evaluate the role of experience-dependent neuronal activity on barrel expansion in birth-enucleated rats by combining various anatomical methods and sensory deprivation paradigms. We show that barrels in birth-enucleated rats were already enlarged by the end of the first week of life and had levels of metabolic activity comparable to those in control rats at different ages. Dewhiskering after the postnatal period of barrel formation did not prevent barrel expansion in adult, birth-enucleated rats. Further, dark rearing and enucleation after barrel formation did not lead to expanded barrels in adult brains. Because incremental increases of somatosensory experience did not promote barrel expansion in birth-enucleated rats, we explored whether shifts of the developmental timing could better explain barrel expansion during the first week of life. Accordingly, birth-enucleated rats show earlier formation of barrels, accelerated growth of somatosensory thalamocortical afferents, and an earlier H4 deacetylation. Interestingly, when H4 deacetylation was prevented with a histone deacetylases inhibitor (valproic acid), barrel specification timing returned to normal and barrel expansion did not occur. Thus, we provide evidence supporting that shifts in developmental timing modulated through epigenetic mechanisms, and not increased levels of experience dependent neuronal activity, promote barrel expansion in the primary somatosensory cortex of rats enucleated at birth. PMID:23372796

  12. Ankyrin and band 3 differentially affect expression of membrane glycoproteins but are not required for erythroblast enucleation

    SciTech Connect

    Ji, Peng; Lodish, Harvey F.

    2012-01-27

    Highlights: Black-Right-Pointing-Pointer Ankyrin and band 3 are not required for erythroblasts enucleation. Black-Right-Pointing-Pointer Loss of ankyrin does not affect erythroid membrane glycoprotein expression. Black-Right-Pointing-Pointer Loss of band 3 influences erythroid membrane glycoprotein expression. -- Abstract: During late stages of mammalian erythropoiesis the nucleus undergoes chromatin condensation, migration to the plasma membrane, and extrusion from the cytoplasm surrounded by a segment of plasma membrane. Since nuclear condensation occurs in all vertebrates, mammalian erythroid membrane and cytoskeleton proteins were implicated as playing important roles in mediating the movement and extrusion of the nucleus. Here we use erythroid ankyrin deficient and band 3 knockout mouse models to show that band 3, but not ankyrin, plays an important role in regulating the level of erythroid cell membrane proteins, as evidenced by decreased cell surface expression of glycophorin A in band 3 knockout mice. However, neither band 3 nor ankyrin are required for enucleation. These results demonstrate that mammalian erythroblast enucleation does not depend on the membrane integrity generated by the ankyrin-band 3 complex.

  13. Lasers.

    PubMed

    Passeron, T

    2012-12-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients.

  14. [Lasers].

    PubMed

    Passeron, T

    2012-11-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be successfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-au-lait macules should not be treated as the relapses are nearly constant. Due to its complex pathophysiology, melasma has a special place in hyperpigmented dermatoses. Q-switched lasers (using standard parameters or low fluency) should not be used because of consistent relapses and the high risk of post-inflammatory hyperpigmentation. Paradoxically, targeting the vascular component of the melasma lesion with lasers could have a beneficial effect. However, these results have yet to be confirmed. In all cases, a precise diagnosis of the type of hyperpigmentation is mandatory before any laser treatment, and the limits and the potential side effects of the treatment must be clearly explained to patients.

  15. Globin synthesis in hybrid cells constructed by transplantation of dormant avian erythrocyte nuclei into enucleated fibroblasts.

    PubMed Central

    Bruno, J; Reich, N; Lucas, J J

    1981-01-01

    The polypeptides synthesized by mature embryonic erythrocytes prepared from the peripheral blood of 14- to 15-day-old chicken embryos were analyzed by two-dimensional gel electrophoresis. Fewer than 200 species of polypeptides were detected; the major polypeptides made at this time were identified as the alpha A-, alpha D-, and beta-globin chains. The dormant erythrocyte nuclei were next reactivated to transcriptional competence by transplantation into enucleated mouse or chicken embryo fibroblasts, with frequencies of cytoplast renucleation of about 50 and 90%, respectively. Since large numbers of hybrid cells could be constructed, a biochemical analysis was possible. Electrophoretic analysis of the [35S]methionine-labeled polypeptides made in the hybrid cell types showed that polypeptides having the mobilities of only two (alpha A and alpha D) of the three major adult globin chains were made as major constituents of the hybrid cells. However, analysis of 14C-amino acid-labeled polypeptides revealed that a beta-like polypeptide that lacked methionine was also synthesized in large amounts. This polypeptide was tentatively identified as the early embryonic globin species rho. Globin synthesis was detected as early as 3 h after nuclear transplantation and as late as 18 h, the last time measured in these experiments. It appeared that globin polypeptides made at very early times were translated at least partially from chicken messenger ribonucleic acid introduced into the hybrid cells during fusion, whereas those made at later times were translated primarily from newly synthesized globin messenger ribonucleic acid. The potential usefulness of this hybrid cell system in analyzing mechanisms regulating globin gene expression is discussed. Images PMID:7346715

  16. Early outcome of transurethral enucleation and resection of the prostate versus transurethral resection of the prostate

    PubMed Central

    Palaniappan, Sundaram; Kuo, Tricia Li Chuen; Cheng, Christopher Wai Sam; Foo, Keong Tatt

    2016-01-01

    INTRODUCTION Recurrent prostate adenoma is a long-term complication following transurethral resection of the prostate (TURP). Transurethral enucleation and resection of the prostate (TUERP) is more appealing, since the nodular adenoma can be completely removed through endoscopy. TUERP is also hypothesised to result in a lower frequency of recurrent adenoma. This study aimed to compare the early outcomes of TUERP and TURP, and assess the feasibility and safety of TUERP. METHODS We compared the outcome of 81 patients who underwent TUERP with that of 85 patients who underwent TURP. International prostate symptom score, quality of life score, prostate volume, degree of intravesical prostatic protrusion, maximum flow rate, post-void residual volume and prostate-specific antigen (PSA) level were obtained pre- and postoperatively. Complications (e.g. transfusion rate, incontinence, infection and urethral stricture) were analysed. RESULTS Operative time was significantly longer in the TUERP group compared to the TURP group (85.3 minutes vs. 51.6 minutes). After TUERP, the maximum flow rate was significantly higher (21.1 mL/s vs. 17.1 mL/s) and PSA level was significantly lower (1.2 ng/mL vs. 1.9 ng/mL) than after TURP. The rates of infection, transfusion and urethral stricture were similar for both groups, but the TUERP group had a higher rate of temporary incontinence (13.6% vs. 4.7%). CONCLUSION The lower PSA level and better maximum flow rate achieved following TUERP suggest that prostate adenoma removal was more complete with TUERP. Long-term follow-up is required to establish whether TUERP results in fewer resections for recurrent adenoma. PMID:26875682

  17. [History of laser in BPH therapy].

    PubMed

    Grande, Marco; Facchini, Francesco; Moretti, Matteo; Larosa, Michelangelo; Leone, Marco; Ziglioli, Francesco; Pozzoli, Gian Luigi; Frattini, Antonio

    2014-01-01

    Laser technology has been used in the treatment of BPH for more than 15-20 years in order to challenge transurethral resection of the prostate. The aim of this review article is to analyze the evolution of laser in BPH therapy, from early coagulative techniques - progressively abandoned for their elevated postoperative morbidity and unfavorable outcomes - to the newer techniques of vaporization, resection and enucleation of the prostate. A better comprehension of tissue-laser interactions, the improvement of laser technology and a growing clinical experience have lead to the development of different laser systems (Holmium, KTP, Thulium laser) that challenge TURP. Today, HoLEP and, secondarily, PVP are the laser techniques supported by more clinical evidences and represent valid alternatives to TURP.

  18. Congenital Anophthalmia and Binocular Neonatal Enucleation Differently Affect the Proteome of Primary and Secondary Visual Cortices in Mice

    PubMed Central

    Smolders, Katrien; Hu, Tjing-Tjing; Bronchti, Gilles; Boire, Denis; Arckens, Lutgarde

    2016-01-01

    In blind individuals, visually deprived occipital areas are activated by non-visual stimuli. The extent of this cross-modal activation depends on the age at onset of blindness. Cross-modal inputs have access to several anatomical pathways to reactivate deprived visual areas. Ectopic cross-modal subcortical connections have been shown in anophthalmic animals but not in animals deprived of sight at a later age. Direct and indirect cross-modal cortical connections toward visual areas could also be involved, yet the number of neurons implicated is similar between blind mice and sighted controls. Changes at the axon terminal, dendritic spine or synaptic level are therefore expected upon loss of visual inputs. Here, the proteome of V1, V2M and V2L from P0-enucleated, anophthalmic and sighted mice, sharing a common genetic background (C57BL/6J x ZRDCT/An), was investigated by 2-D DIGE and Western analyses to identify molecular adaptations to enucleation and/or anophthalmia. Few proteins were differentially expressed in enucleated or anophthalmic mice in comparison to sighted mice. The loss of sight affected three pathways: metabolism, synaptic transmission and morphogenesis. Most changes were detected in V1, followed by V2M. Overall, cross-modal adaptations could be promoted in both models of early blindness but not through the exact same molecular strategy. A lower metabolic activity observed in visual areas of blind mice suggests that even if cross-modal inputs reactivate visual areas, they could remain suboptimally processed. PMID:27410964

  19. Fertility and Pregnancy Outcome after Myoma Enucleation by Minilaparotomy under Microsurgical Conditions in Pronounced Uterus Myomatosus.

    PubMed

    Floss, K; Garcia-Rocha, G-J; Kundu, S; von Kaisenberg, C S; Hillemanns, P; Schippert, C

    2015-01-01

    Introduction: Besides the typical complaints and symptoms, myomas can cause sterility, infertility and complications during pregnancy. Laparoscopic interventions reach their limits with regard to organ preservation and the simultaneous desire to have children in the removal of multiple and larger intramural myoma nodes. The aim of this study is to examine fertility status and pregnancy outcome after myoma removal by minilaparotomy (skin incision maximal 8 cm) in women with pronounced uterus myomatosus. Materials and Methods: This retrospective study makes use of the data from 160 patients with an average age of 34.6 years. Factors analysed include number, size and localisation of the myomas, complaints due to the myoma, pre- and postoperative gravidity, mode of delivery, and complications of birth. Results: Indications for organ-sparing myoma enucleation were the desire to have children (72.5 %), bleeding disorders (60 %) and pressure discomfort (36.5 %). On average 4.95 (SD ± 0.41), maximally 46 myomas were removed. The largest myoma had a diameter of 6.64 cm (SD ± 2.74). 82.5 % of the patients had transmural myomas, in 17.5 % the uterine cavity was inadvertently opened. On average the operating time was 163 minutes (SD ± 45.47), the blood loss 1.59 g/dL (SD ± 0.955). 60.3 % of the patients with the desire to have children became pregnant postoperatively. 75.3 % of the pregnancies were on average carried through to the 38th week (28.4 % vaginal deliveries, 71.6 % Caesarean sections). In the postoperative period there was one case of uterine rupture in the vicinity of a previous scar. Discussion: By means of the microsurgical "mini-laparotomy" even extensive myomatous uterine changes can, in the majority of cases, be operated in an organ-sparing manner with retention of the ability to conceive and to carry a pregnancy through to maturity of the infant. The risk for a postoperative uterine rupture in a subsequent pregnancy and

  20. Development of inter-family nuclear transplant embryos by transplanting the nuclei from the loach blastulae into the non-enucleated zebrafish eggs

    NASA Astrophysics Data System (ADS)

    Li, Li; Zhang, Shicui; Yuan, Jinduo; Li, Hongyan

    2003-03-01

    The developmental fate of the pronuclei in recombined embryos obtained by transplanting the donor nuclei into the non-enucleated eggs remains controversial in the case of fish. In the present study, the nuclei from the loach blastulae were transplanted into non-enucleated zebrafish eggs, the resulting 9 inter-family nuclear transplant embryos developed to larval stages. Although the development timing of the nuclear transplants resembled that of zebrafish, chromosome examination revealed that most of the recombined embryos were diploids with karyotype characteristic of loach, which was also proved by RAPD analysis. Moreover, 3 out of the 9 larval fish formed barb rudiments specific to loach. It was therefore concluded that the nuclear transplant larval fish were inter-family nucleo-cytoplasmic hybrids; and that only the donor nuclei were involved in the development of the nuclear transplant embryos, while the pronuclei in the non-enucleated eggs were likely automatically eliminated during the development.

  1. Recovery of cell nuclei from 15,000 years old mammoth tissues and its injection into mouse enucleated matured oocytes.

    PubMed

    Kato, Hiromi; Anzai, Masayuki; Mitani, Tasuku; Morita, Masahiro; Nishiyama, Yui; Nakao, Akemi; Kondo, Kenji; Lazarev, Petr A; Ohtani, Tsuyoshi; Shibata, Yasuyuki; Iritani, Akira

    2009-01-01

    Here, we report the recovery of cell nuclei from 14,000-15,000 years old mammoth tissues and the injection of those nuclei into mouse enucleated matured oocytes by somatic cell nuclear transfer (SCNT). From both skin and muscle tissues, cell nucleus-like structures were successfully recovered. Those nuclei were then injected into enucleated oocytes and more than half of the oocytes were able to survive. Injected nuclei were not taken apart and remained its nuclear structure. Those oocytes did not show disappearance of nuclear membrane or premature chromosome condensation (PCC) at 1 hour after injection and did not form pronuclear-like structures at 7 hours after injection. As half of the oocytes injected with nuclei derived from frozen-thawed mouse bone marrow cells were able to form pronuclear-like structures, it might be possible to promote the cell cycle of nuclei from ancient animal tissues by suitable pre-treatment in SCNT. This is the first report of SCNT with nuclei derived from mammoth tissues.

  2. Rat Blastocysts from Nuclear Injection and Time-Lagged Enucleation and Their Commitment to Embryonic Stem Cells.

    PubMed

    Hara, Hiromasa; Goto, Teppei; Takizawa, Akiko; Sanbo, Makoto; Jacob, Howard J; Kobayashi, Toshihiro; Nakauchi, Hiromitsu; Hochi, Shinichi; Hirabayashi, Masumi

    2016-04-01

    Pronucleus-like vesicle formation following premature chromosome condensation (PCC) of the donor cell nucleus is the key event for successful generation of cloned rodents by nuclear transplantation (NT). However in rat cloning, this change is difficult to induce in enucleated recipient oocytes because of their inability to maintain maturation-promoting factor levels. In this study, intact oocytes retrieved from nuclear-visualized H2B-tdTomato knock-in rats were injected with Venus-labeled cell nuclei. Because the incidence of PCC under MG-132 treatment significantly increased with the culture period (0%, 10.8%, 36.8%, and 87.5% at 0, 0.5, 1, and 2 h postinjection, respectively), the metaphase plate of the oocyte was removed 1-2 h after the nuclear injection. The NT-derived rat zygotes (n = 748) were activated with ionomycin/cycloheximide and transferred into temporal host mothers, resulting in the harvest of three blastocysts (0.4%) with Venus fluorescence. Two blastocysts were examined for their potential to commit to NT-derived embryonic stem cells (ntESCs). One ntESC line was established successfully and found to be competent in terms of karyotype, stem cell marker expression, and pluripotency. In conclusion, time-lagged enucleation of visualized oocyte nuclei allows the PCC incidence of donor nuclei and generation of NT blastocysts, and the blastocysts can commit to germline-competent ntESCs.

  3. Milrinone treatment of bovine oocytes during in vitro maturation benefits production of nuclear transfer embryos by improving enucleation rate and developmental competence.

    PubMed

    Naruse, Kenji; Iga, Kosuke; Shimizu, Manabu; Takenouchi, Naoki; Akagi, Satoshi; Somfai, Tamas; Hirao, Yuji

    2012-01-01

    In the production of cattle nuclear transfer embryos, the production efficiency is affected by the oocyte developmental competence and successful enucleation rate. This study investigated the effect of treating oocytes with milrinone, a phosphodiesterase inhibitor, on these two characteristics. When cumulus-oocyte complexes (COCs) were cultured for 19 h with 0, 50 or 100 μM of milrinone, the enucleation rate was significantly improved by 100 μM milrinone. However, milrinone treatment during in vitro maturation (IVM) also delayed meiotic progression by at least 2 h, which would affect the examination of enucleation rate and developmental competence of oocytes. Thus, in the second experiment, meiotic resumption was temporarily inhibited with butyrolactone I (BL-I; 100 μM, 18 h) to decrease the delayed maturation caused by milrinone; this enabled a more accurate comparison of the effects of milrinone after oocyte maturation. In nuclear transfer embryo production, oocytes treated with milrinone (100 μM, 20 h) showed a significantly higher rate of enucleation compared with that of control oocytes. This improved enucleation rate was associated with a closer location of the metaphase plate to the first polar body in the treated oocytes compared with that in control oocytes. Furthermore, milrinone improved the frequency of development to the blastocyst stage in the resulting embryos. In conclusion, milrinone supplementation during IVM improved enucleation rates by rendering the metaphase plate in close proximity to the first polar body, and this treatment also improved oocyte developmental competence. These benefits additively improved the yield of cloned embryos that developed to the blastocyst stage.

  4. Holmium laser for treatment of benign prostatic hyperplasia: old wine in a new bottle?

    NASA Astrophysics Data System (ADS)

    Nelius, Thomas; de Riese, Werner T. W.

    2003-06-01

    Urinary tract symptoms related to benign prostatic hyperplasia affect 70% of men older than 70 years. Complications are common problems and a significant cause of morbidity in this population, placing a considerable burden on health services. In the early 1990s laser treatment of benign prostatic hyperplasia became widely used after the introduction of the side-firing neodym: YAG laser. However, because of technical limitations and inferior results compared to classical transurethral resection of the prostate many Urologists became desinterested in this device. With the introduction of the holmium: YAG laser a new laser generation became available for use in Urology. Beside several other applications the holmium: YAG laser can be used for incision, ablation, resection, and more recently enucleation of the prostate. In this paper we reviewed the current literature regarding the holmium: YAG laser resection and enucleation of the prostate compared to transurethral resection of the prostate and open prostatectomy. The holmium: YAG laser technique is an effective and durable surgical alternative to standard transurethral resection of the prostate. Interestingly, enucleation of the prostate with this device seems to be a safe and effective procedure for large prostatic adenomas, it may become an attractive alternative to open prostatectomy.

  5. Laser therapy in intraocular tumors

    NASA Astrophysics Data System (ADS)

    Carstocea, Benone D.; Gafencu, Otilia L.; Apostol, Silvia

    1995-01-01

    Intraocular tumors present special problems of diagnosis and treatment. Diagnostic methods include, in addition to systemic and ophthalmological examinations, ancillary examinations such as transillumination, fluorescein angiography, ultrasonography, radioactive phosphorus uptake test, radiology, computerized tomography, and fine-needle aspiration biopsy with cytological analyses. Previously, enucleation of the involved eye was generally accepted as management of malignant tumors. Improved therapeutic methods such as photocoagulation and better surgical techniques now provide a variety of therapeutical alternatives. This study consists of 21 cases of intraocular tumors that were managed by Argon laser photocoagulation. Four cases were intraocular metastasis and 17 cases were primitive intraocular tumors. Argon laser therapy proved to be totally ineffective for the intraocular metastasis and a very adequate therapy for the primitive tumors. Tumor extirpations (choroidal, cillary body, or iris tumors) using laser lancet proved to be more suitable than classic surgery.

  6. Therapy monitoring of laser cyclophotocoagulation

    NASA Astrophysics Data System (ADS)

    Oberheide, Uwe; Lee, Christoph; Krebs, Ronald; Welling, Herbert; Ertmer, Wolfgang; Lubatschowski, Holger

    2002-06-01

    Laser induced ultrasound provides a powerful tool for solving a major problem of laser cyclophotocoagulation, which is caused by difficulties in localization and determination of optical properties. Furthermore it adds the possibility of an online control mechanism for the process of coagulation of the ciliary body. We have developed a transducer system which is based on a fiber with 600 micrometers core diameter surrounded by a ring shaped piezoelectric PVDF detector. With this detector it is possible to localize the lateral position of the ciliary body on enucleated pigs and rabbit eyes as well as its depth. Our findings correspond well with histological sections of the measured area. Additionally, the changes in the tissue's optical properties induced by coagulation with a diode laser have been detected in real time.

  7. Outflow facility efficacy of five drugs in enucleated porcine eyes by a method of constant-pressure perfusion

    PubMed Central

    Li, Ning; Shi, Hui-Min; Cong, Lin; Lu, Zhao-Zeng; Ye, Wen; Zhang, Yu-Yan

    2015-01-01

    This study aimed to characterize a technique that assesses the outflow facility (C) efficacy of five kinds of IOP-lowering drugs commonly used clinically in enucleated porcine Eyes. Eyes were perfused at 15 mmHg with GPBS first to establish the baseline outflow facility (C0). Then the anterior chamber contents were exchanged for GPBS with corresponding concentration eye drops (4.9×103 nM Brimonidine, 41.1 nM Latanoprost, 3.4×103 nM Levobunolol, 3.0×103 nM Brinzolamide, 8.3×103 nM Pilocarpine) in five groups (n = 6 each), while 6 eyes received GPBS alone as control. The mean stable facility obtained after drug administration (C1) was continuously recorded. The changes between C0 and C1 (ΔC = C1-C0) were analyzed. Finally, for drugs among the five experiment groups with statistical significance, the concentration was reduced 3 times, otherwise the drugs’ concentration was increased to 10 times to confirm its effectiveness further using the same methods (n = 6 each). We found that the average baseline outflow facility was 0.24±0.01 μl·min-1·mmHg-1. C increased significantly in Brimonidine and Latanoprost groups, even the concentration of Brimonidine and Latanoprost was decreased 3 times (P < 0.05). However, there was no significantly increase in Levobunolol, Brinzolamide, Pilocarpine and control group (P > 0.05), but when drugs’ concentration was increased to 10 times, the C value of Pilocarpine decreased significantly (P = 0.04). No significant washout effects in porcine eyes were observed. To conclude, outflow facility efficacy of five drugs in enucleated porcine eyes may provide a reference for clinical medicine. A constant-pressure perfusion technique should be useful to evaluate effect of pharmacologic agents or surgical manipulations on aqueous humor dynamics. PMID:26221257

  8. Laser thermokeratoplasty by means of a continuously emitting laser diode in the mid IR

    NASA Astrophysics Data System (ADS)

    Brinkmann, Ralf; Koop, Norbert; Kamm, Katharina; Geerling, Gerd; Kampmeier, Juergen; Birngruber, Reginald

    1996-12-01

    Laser thermokeratoplasty (LTK) has been performed with a continuously emitting, tunable laser diode at 1.86 micrometers . A study on enucleated porcine eyes was conducted in order to demonstrate the feasibility of this laser source for LTK and to determine the useful irradiation modalities. Refractive changes achieved with different application systems and a standard coagulation pattern, consisting of 8 coagulation spots on a 6 mm ring, were measured. The most promising sets of parameters were carried out in a first animal study with mini pigs. Initial refractive changes up to 6 D could be achieved in vitro and in vivo with laser powers between 120 mW and 200 mW and irradiation times of several seconds. In conclusion, the mid-IR laser diode operated at a wavelength of 1.86 micrometers seems to be the optimal source for a clinical LTK system.

  9. Inhibition of secondary cartilage of the intermaxillary suture in Sprague-Dawley rats following the enucleation of maxillary molars

    SciTech Connect

    Forbes, D.P.; Al-Bareedi, S.

    1986-01-01

    A single craniofacial suture can undergo several morphologic transformations during its development. From 3 to 7 weeks of age, the intermaxillary suture of the rat is synchondrotic in character, featuring secondary cartilage; at later times, this suture is syndesmotic in character, featuring a fibrous tissue interface. Since intermittent mechanical stimulation has been reported to initiate secondary cartilage formation, a study was done to determine if the functioning dentition were responsible for secondary cartilage formation in the intermaxillary suture of the rat. Twenty-two female Sprague-Dawley rats were used. At 3 weeks of age, prior to eruption, the maxillary molars were enucleated from nine animals. Body weights were recorded weekly. Animals were sacrificed weekly from 4 to 7 weeks of age. One hour prior to sacrifice, each rat was injected with (/sup 35/S)sulfate at a dosage of 2 microCi/g body weight. The tissues were evaluated by light microscopy and autoradiography. In the experimental group, the midpalatal suture did not undergo the normal synchondrotic transformation. Instead, this suture remained fibrous with negligible metachromatic staining. In the control animals, the peak period of (/sup 35/S)sulfate incorporation was 4 weeks of age and was five times greater than in the experimental group. The primary stimulus for the initiation of secondary cartilage formation in the midpalatal suture of the rat was molar function. Also, functioning molars were found to be important in the maintenance of the palatal bone.

  10. Laser pointers and the human eye: a clinicopathologic study.

    PubMed

    Robertson, D M; Lim, T H; Salomao, D R; Link, T P; Rowe, R L; McLaren, J W

    2000-12-01

    We report the absence of photic retinal injury after exposing the retina to light from class 3A laser pointers for durations of up to 15 minutes. Three patients with uveal melanomas were scheduled to have an enucleation. Each agreed to have his or her retina exposed to laser light from a class 3A laser pointer prior to enucleation. Continuous exposure was directed to the fovea for 1 minute, to the retina 5 degrees below fixation for 5 minutes, and to the retina 5 degrees above fixation for 15 minutes. Ophthalmoscopic evaluation of the cornea, lens, and retina and fluorescein angiographic studies of the retina were conducted before, 24 hours after, and 11 days after laser exposure in the first case; before and 86 hours after exposure in the second case; and before, 96 hours after, and 15 days after exposure in the third case. Other than transient afterimages that lasted only a few minutes, we were unable to document any functional, ophthalmoscopic, fluorescein angiographic, or histologic evidence of damage to any structures of the eyes. Transmission electron microscopic studies of retinal sites targeted by the laser pointers in the second and third cases revealed ultrastructural abnormalities in the outer retina and the pigment epithelium that were similar to abnormalities seen in the retina approximately 8 mm away from the targeted sites. The risk to the human eye from transient exposure to light from commercially available class 3A laser pointers having powers of 1, 2, and 5 mW seems negligible.

  11. The role of lasers in modern urology

    PubMed Central

    Dołowy, Łukasz; Dembowski, Janusz; Zdrojowy, Romuald; Kołodziej, Anna

    2015-01-01

    Introduction The functioning of modern urological departments and the high level of service they provide is possible through, among other things, the use of modern laser techniques. Material and methods Open operations have been replaced by minimally invasive procedures, and classical surgical tools by advanced lasers. The search for new applications with lasers began as technology developed. Among many devices available, holmium, diode and thulium lasers are currently the most popular. Results Depending on the wavelength, the absorption by water and hemoglobin and the depth of penetration, lasers can be used for coagulation, vaporization and enucleation. In many centres, after all the possibilities of pharmacological treatment have been exhausted, lasers are used as the primary treatment for patients with benign prostatic hyperplasia, with therapeutic results that are better than those obtained through open or endoscopic operations. The use of lasers in the treatment of urolithiasis, urinary strictures and bladder tumours has made treatment of older patients with multiple comorbidities safe, without further necessity to modify the anticoagulant drug treatment. Laser procedures are additionally less invasive, reduce hospitalization time and enable a shorter bladder catheterization time, sometimes even eliminating the need for bladder catherterization completely. Such procedures are also characterized by more stable outcomes and a lower number of reoperations. Conclusions There are also indications that with the increased competition among laser manufacturers, decreased purchase and maintenance costs, and increased operational safety, laser equipment will become mandatory and indispensable asset in all urology wards. PMID:26251737

  12. Laser therapy in ocular tumors

    NASA Astrophysics Data System (ADS)

    Carstocea, Benone D.; Gafencu, Otilia L.; Apostol, Silvia; Ionita, Marcel A.; Moroseanu, A.; Dascalu, Traian; Lupei, Voicu; Ionita-Manzatu, V.

    1998-07-01

    The medical laser equipments made at NILPRP have been exploited intensively for more than 10 years at CMH. The availability and reliability of the first like-on equipment have increased, following improvements in optical delivery system and cooling circuit. This paper shows the impact of technical advances on the development of ophthalmologic laser therapy. Intraocular tumors pose special problems of diagnosis and treatment. Diagnostic methods include addition to systemic and ophthalmologic examinations, ancillary examinations, such as transillumination, fluorescence angiography, ultrasonography, radioactive phosphorus uptake tests, radiology, computerized tomography and fine-needle aspiration biopsy with cytological analyses. The enucleation of the involved eye used to be a generally accepted management of malignant tumors. Improved therapeutic methods such as photocoagulation and better surgical techniques now provide a variety of therapeutic alternatives. This study covers 31 cases of intraocular tumors that were managed either by Argon Laser photocoagulation and/or by Nd:YAG laser surgical treatment. Four cases were intraocular metastasse and 17 cases were primitive intraocular tumors. Argon laser therapy proved to be totally ineffective for intraocular metastasse but very adequate therapy for primitive tumors. Tumor extirpations (choroidal, cillary body or iris tumors) using Nd:YAG laser lancet proved to be more suitable than classic surgery.

  13. Different lasers in the treatment of benign prostatic hyperplasia: a network meta-analysis.

    PubMed

    Zhang, Xingming; Shen, Pengfei; He, Qiying; Yin, Xiaoxue; Chen, Zhibin; Gui, Haojun; Shu, Kunpeng; Tang, Qidun; Yang, Yaojing; Pan, Xiuyi; Wang, Jia; Chen, Ni; Zeng, Hao

    2016-03-24

    All available surgical treatments for benign prostatic hyperplasia (BPH) have their individual advantages or disadvantages. However, the lack of head-to-head studies comparing different surgeries makes it unavailable to conduct direct analysis. To compare the efficacy and safety among different lasers and transurethral resection of prostate (TURP) for BPH, randomized controlled trials were searched in MEDLINE, EMBASE, Cochrane library, WHO International Clinical Trial Registration Platform, and Clinical Trial.gov by 2015.5; and the effectiveness-, perioperation- and complication-related outcomes were assessed by network meta-analysis. 36 studies involving 3831 patients were included. Holmium laser through resection and enucleation had the best efficacy in maximum flow rate. Thulium laser through vapo-resection was superior in improving international prostate symptom score and holmium laser through enucleation was the best for post-voiding residual volume improvement. Diode laser through vaporization was the rapidest in removing postoperative indwelling catheter, while TURP was the longest. TURP required the longest hospitalization and thulium laser through vapo-resection was relatively shorter. Holmium and thulium lasers seem to be relatively better in surgical efficacy and safety, so that these two lasers might be preferred in selection of optimal laser surgery. Actually, more large-scale and high quality head-to-head RCTs are suggested to validate the conclusions.

  14. Different lasers in the treatment of benign prostatic hyperplasia: a network meta-analysis

    PubMed Central

    Zhang, Xingming; Shen, Pengfei; He, Qiying; Yin, Xiaoxue; Chen, Zhibin; Gui, Haojun; Shu, Kunpeng; Tang, Qidun; Yang, Yaojing; Pan, Xiuyi; Wang, Jia; Chen, Ni; Zeng, Hao

    2016-01-01

    All available surgical treatments for benign prostatic hyperplasia (BPH) have their individual advantages or disadvantages. However, the lack of head-to-head studies comparing different surgeries makes it unavailable to conduct direct analysis. To compare the efficacy and safety among different lasers and transurethral resection of prostate (TURP) for BPH, randomized controlled trials were searched in MEDLINE, EMBASE, Cochrane library, WHO International Clinical Trial Registration Platform, and Clinical Trial.gov by 2015.5; and the effectiveness-, perioperation- and complication-related outcomes were assessed by network meta-analysis. 36 studies involving 3831 patients were included. Holmium laser through resection and enucleation had the best efficacy in maximum flow rate. Thulium laser through vapo-resection was superior in improving international prostate symptom score and holmium laser through enucleation was the best for post-voiding residual volume improvement. Diode laser through vaporization was the rapidest in removing postoperative indwelling catheter, while TURP was the longest. TURP required the longest hospitalization and thulium laser through vapo-resection was relatively shorter. Holmium and thulium lasers seem to be relatively better in surgical efficacy and safety, so that these two lasers might be preferred in selection of optimal laser surgery. Actually, more large-scale and high quality head-to-head RCTs are suggested to validate the conclusions. PMID:27009501

  15. Can Low Level Laser Therapy Benefit Bone Regeneration in Localized Maxillary Cystic Defects? - A Prospective Randomized Control Trial

    PubMed Central

    Zaky, Ahmed Abbas; El Shenawy, Hanaa Mohamed Mohamed; Harhsh, Tarek Abdel Hamed; Shalash, Mahmoud; Awad, Noha Mohamed Ismael

    2016-01-01

    AIM: The aim of the study was to evaluate the effect of Low-Level Laser Therapy (LLLT) on bone formation in cystic defects following cyst enucleation. PATIENTS AND METHODS: The sample was composed of sixteen patients with enucleated maxillary bony cystic lesions. With an age range from 20 - 44 grouped as eight Laser and eight Control patients. Laser group was subjected to low intensity diode laser immediately after surgery and then for three times per week for two weeks using a therapeutic laser irradiation. Group B (control group): patients were not subjected laser therapy. RESULTS: The predictor variable was exposure of bone defect to LLLT or none. The outcome variable was bone density changes measured by digital radiographs at day 1 and days 90 postoperatively. Descriptive and bivariate statistics were computed. There were no statistically significant differences between the 2 groups for the bone density at day 1. There was a statistically significant difference in bone density changes in each group at day 90: Significant at P ≤ 0.05. After adjusting for differences in day 1 for bone density, the estimated mean change in bone density changes at day 90 was significantly larger for Laser compared with control. CONCLUSION: The results of this study suggested that LLLT can enhance bone healing in maxillary cystic defects. This can serve as an adjunct method in preventing possible delayed healing and pathological fractures This also will be helpful for more researchers in early loading in case of dental implants to accelerate osseointegration. PMID:28028422

  16. Diffusion Tensor Imaging Detects Early Cerebral Cortex Abnormalities in Neuronal Architecture Induced by Bilateral Neonatal Enucleation: An Experimental Model in the Ferret

    PubMed Central

    Bock, Andrew S.; Olavarria, Jaime F.; Leigland, Lindsey A.; Taber, Erin N.; Jespersen, Sune N.; Kroenke, Christopher D.

    2010-01-01

    Diffusion tensor imaging (DTI) is a technique that non-invasively provides quantitative measures of water translational diffusion, including fractional anisotropy (FA), that are sensitive to the shape and orientation of cellular elements, such as axons, dendrites and cell somas. For several neurodevelopmental disorders, histopathological investigations have identified abnormalities in the architecture of pyramidal neurons at early stages of cerebral cortex development. To assess the potential capability of DTI to detect neuromorphological abnormalities within the developing cerebral cortex, we compare changes in cortical FA with changes in neuronal architecture and connectivity induced by bilateral enucleation at postnatal day 7 (BEP7) in ferrets. We show here that the visual callosal pattern in BEP7 ferrets is more irregular and occupies a significantly greater cortical area compared to controls at adulthood. To determine whether development of the cerebral cortex is altered in BEP7 ferrets in a manner detectable by DTI, cortical FA was compared in control and BEP7 animals on postnatal day 31. Visual cortex, but not rostrally adjacent non-visual cortex, exhibits higher FA than control animals, consistent with BEP7 animals possessing axonal and dendritic arbors of reduced complexity than age-matched controls. Subsequent to DTI, Golgi-staining and analysis methods were used to identify regions, restricted to visual areas, in which the orientation distribution of neuronal processes is significantly more concentrated than in control ferrets. Together, these findings suggest that DTI can be of utility for detecting abnormalities associated with neurodevelopmental disorders at early stages of cerebral cortical development, and that the neonatally enucleated ferret is a useful animal model system for systematically assessing the potential of this new diagnostic strategy. PMID:21048904

  17. Treatment of Hemorrhagic Vocal Polyps by Pulsed Dye Laser-Assisted Laryngomicrosurgery

    PubMed Central

    Byeon, Hyung Kwon; Han, Ji Hyuk; Choi, Byeong Il; Hwang, Hye Jin; Kim, Ji-Hoon; Choi, Hong-Shik

    2015-01-01

    Objective. Conventional surgical techniques of laryngomicrosurgery (LMS) on hemorrhagic vocal polyps are often difficult due to obscuration of the surgical field by inadvertent bleeding from the lesion, and there are often significant amounts of mucosal epithelium loss. Here, we introduce our surgical technique using pulsed dye laser (PDL), which can effectively resect the polyp with vocal fold mucosa preservation. Methods. Patients who were diagnosed with hemorrhagic vocal polyp and who were surgically managed using PDL from March 2013 to October 2014 were retrospectively reviewed. Preoperative and postoperative clinical outcomes and surgical findings were evaluated. Results. A total of 39 patients were treated with PDL-assisted enucleation LMS. The average age was 43.7 years (range 20–73), and there were 20 males and 19 females (17 professional voice users). In all cases, the hemorrhagic polyp was successfully enucleated after application of PDL, thereby preserving the overlying epithelium. Postoperative voice outcomes were favorable with clear preservation of the vocal fold mucosal wave. Conclusion. PDL-assisted enucleation LMS for the treatment of hemorrhagic vocal polyps can be a safe and effective surgical technique. It can be considered a promising treatment option for hemorrhagic vocal polyps. PMID:26557700

  18. Safety of cornea and iris in ocular surgery with 355-nm lasers.

    PubMed

    Wang, Jenny; Chung, Jae Lim; Schuele, Georg; Vankov, Alexander; Dalal, Roopa; Wiltberger, Michael; Palanker, Daniel

    2015-09-01

    A recent study showed that 355-nm nanosecond lasers cut cornea with similar precision to infrared femtosecond lasers. However, use of ultraviolet wavelength requires precise assessment of ocular safety to determine the range of possible ophthalmic applications. In this study, the 355-nm nanosecond laser was evaluated for corneal and iris damage in rabbit, porcine, and human donor eyes as determined by minimum visible lesion (MVL) observation, live/dead staining of the endothelium, and apoptosis assay. Single-pulse damage to the iris was evaluated on porcine eyes using live/dead staining. In live rabbits, the cumulative median effective dose (ED50) for corneal damage was 231 J/cm2, as seen by lesion observation. Appearance of endothelial damage in live/dead staining or apoptosis occurred at higher radiant exposure of 287 J/cm2. On enucleated rabbit and porcine corneas, ED50 was 87 and 52 J/cm2, respectively, by MVL, and 241 and 160 J/cm2 for endothelial damage. In human eyes, ED50 for MVL was 110 J/cm2 and endothelial damage at 453 J/cm2. Single-pulse iris damage occurred at ED 50 of 208 mJ/cm2. These values determine the energy permitted for surgical patterns and can guide development of ophthalmic laser systems. Lower damage threshold in corneas of enucleated eyes versus live rabbits is noted for future safety evaluation.

  19. Establishment of pregnancy after the transfer of nuclear transfer embryos produced from the fusion of argali (Ovis ammon) nuclei into domestic sheep (Ovis aries) enucleated oocytes.

    PubMed

    White, K L; Bunch, T D; Mitalipov, S; Reed, W A

    1999-01-01

    Cloning mammalian species from cell lines of adult animals has been demonstrated. Aside from its importance for cloning multiple copies of genetically valuable livestock, cloning now has the potential to salvage endangered or even extinct species. The aim of this study was to investigate the effect of the bovine and domestic (Ovis aries) ovine oocyte cytoplasm on the nucleus of an established cell line from an endangered argali wild sheep (Ovis ammon) after nuclear transplantation. A fibroblast cell line was established from skin biopsies from an adult argali ram from the People's Republic of China. Early karyotype analysis of cells between 3-6 passages revealed a normal diploid chromosome number of 56. The argali karyotype consisted of 2 pairs of biarmed and 25 pairs of acrocentric autosomes, a large acrocentric and minute biarmed Y. Bovine ovaries were collected from a local abattoir, oocytes aspirated, and immediately placed in maturation medium consisting of M-199 containing 10% fetal bovine serum, 100 IU/mL penicillin, 100 microg/mL streptomycin, 0.5 microg/mL follicle-stimulating hormone (FSH), 5.0 microg/mL luetinizing hormone (LH) and 1.0 microg/mL estradiol. Ovine (O. aries) oocytes were collected at surgery 25 hours postonset of estrus from the oviducts of superovulated donor animals. All cultures were carried out at 39 degrees C in a humidified atmosphere of 5% CO2 and air. In vitro matured MII bovine oocytes were enucleated 16-20 hours after onset of maturation and ovine oocytes within 2-3 hours after collection. Enucleation was confirmed using Hoechst 33342 and UV light. The donor argali cells were synchronized in G0-G1 phase by culturing in Dulbecco's modified Eagle's medium (DMEM) plus 0.5% fetal bovine serum for 5-10 days. Fusion of nuclear donor cell to an enucleated oocyte (cytoplast) to produce nuclear transfer (NT) embryos was induced by 2 electric pulses of 1.4 kV/cm for 30 microsc. Fused NT embryos were activated after 24 hours of maturation

  20. Laser apparatus

    NASA Technical Reports Server (NTRS)

    Koepf, G. A. (Inventor)

    1979-01-01

    A laser apparatus having a pump laser device for producing pump laser energy upon being excited is disclosed. The pump laser device has a resonating cavity for oscillating and amplifying the pump laser energy. A source laser device is used for producing source laser energy upon being excited by the pump laser energy. The source laser device has a resonating cavity for oscillating and amplifying the source laser energy. The source laser's resonating cavity is coupled within a portion of the pump laser's resonating cavity.

  1. Chemically Assisted Enucleation Results in Higher G6PD Expression in Early Bovine Female Embryos Obtained by Somatic Cell Nuclear Transfer

    PubMed Central

    Oliveira, Clara Slade; Tetzner, Tatiane Almeida Drummond; de Lima, Marina Ragagnin; de Melo, Danilas Salinet; Niciura, Simone Cristina Méo; Garcia, Joaquim Mansano

    2012-01-01

    Abstract Despite extensive efforts, low efficiency is still an issue in bovine somatic cell nuclear transfer (SCNT). The hypothesis of our study was that the use of cytoplasts produced by chemically assisted enucleation (EN) would improve nuclear reprogramming in nuclear transfer (NT)–derived embryos because it results in lower damage and higher cytoplasm content than conventional EN. For that purpose, we investigated the expression of two X-linked genes: X inactive-specific transcript (XIST) and glucose 6-phosphate dehydrogenase (G6PD). In the first experiment, gene expression was assessed in day-7 female blastocysts from embryonic cell NT (ECNT) groups [conventional, ECNT conv; chemically assisted, ECNT deme (demecolcine)]. Whereas in the ECNT conv group, only one embryo (25%; n=4) expressed XIST transcripts, most embryos showed XIST expression (75%; n=4) in the ECNT deme group. However, no significant differences in transcript abundance of XIST and G6PD were found when comparing the embryos from all groups. In a second experiment using somatic cells as nuclear donors, we evaluated gene expression profiles in female SCNT-derived embryos. No significant differences in relative abundance (RA) of XIST transcripts were observed among the groups. Nonetheless, higher (p<0.05) levels of G6PD were observed in SCNT deme and in vitro–derived groups in comparison to SCNT conv. To know whether higher G6PD expression in embryos derived from SCNT chemically assisted EN indicates higher metabolism in embryos considered of superior quality or if the presence of higher reactive oxygen species (ROS) levels generated by the increased oxygen consumption triggers G6PD activation, the expression of genes related to stress response should be investigated in embryos produced by that technique. PMID:22908977

  2. Current Laser Treatments for Benign Prostatic Hyperplasia

    PubMed Central

    Son, Hwancheol; Song, Sang Hoon

    2010-01-01

    The latest technical improvements in the surgical armamentarium are remarkable. In particular, advancements in the urologic field are so exceptional that we could observe the flare-up of robot-assisted laparoscopic radical prostatectomy for prostate cancer and laser prostatectomy for benign prostatic hyperplasia (BPH). Photoselective vaporization of the prostate (PVP) and holmium laser prostatectomy are the most generalized options for laser surgery of BPH, and both modalities have shown good postoperative results. In comparison to transurethral prostatectomy (TURP), they showed similar efficacy and a much lower complication rate in randomized prospective clinical trials. Even in cases of large prostates, laser prostatectomy showed comparable efficacy and safety profiles compared to open prostatectomy. From a technical point of view, PVP is considered to be an easier technique for the urologist to master. Furthermore, patients can be safely followed up in an outpatient clinic. Holmium laser enucleation of the prostate (HoLEP) mimics open prostatectomy because the adenomatous tissue is peeled off the surgical capsule in both procedures. Therefore, HoLEP shows notable volume reduction of the prostate similar to open prostatectomy with fewer blood transfusions, shorter hospital stay, and cost reduction regardless of prostate size. Outcomes of laser prostatectomy for BPH are encouraging but sometimes are unbalanced because safety and feasibility studies were reported mainly for PVP, whereas long-term data are mostly available for HoLEP. We need longer-term randomized clinical data to identify the reoperation rate of PVP and to determine which procedure is the ideal alternative to TURP and open prostatectomy for each patient. PMID:21165192

  3. [A Case of Holmium: YAG Laser Resection of Superficial Bladder Tumor (HoLRBT)].

    PubMed

    Sugita, Yoshiko; Shitara, Toshiya; Hirayama, Takahiro; Fujita, Tetsuo; Yoshida, Kazunari; Kubo, Seiichi; Iwamura, Masatsugu

    2015-10-01

    We present a case of holmium : YAG laser resection of superficial bladder tumor (HoLRBT). A 73-year-old male was referred to our hospital with elevated prostatic specific antigen. Due to difficulty of urination, holmium : YAG laser enucleation of the prostate was performed under the diagnosis of benign prostatic hyperplasia. During the surgery, superficial bladder tumor was incidentally identified, and HoLRBT was performed. After the operation, histopathological examination revealed urothelial carcinoma, G2 > G1, pTa. The patient has been subsequently followed up for 9 months, and there areno evidence of recurrence. Changing the holmium : YAG laser energy setting can potentially be effective and safe to approach a superficial bladder tumor.

  4. Noncontact tonometry using laser interferometry

    NASA Astrophysics Data System (ADS)

    Drescher, Joerg; Stork, Wilhelm; Hey, Stefan; Gundlach, Arnd; Mueller-Glaser, Klaus-Dieter; Kreiner, Christine F.

    1999-02-01

    This paper describes a new method to examine the intraocular pressure (IOP) without any contact to the eye. In our new approach the IOP is determined indirectly from the acoustic properties of the eye as the resonance frequencies of the bulbus are shifting with increasing IOP. Simulations with the Finite Element Method were done to explore the coherence between the IOP and the acoustic properties of the bulbus. A three-dimensional model of the eye was developed comprising the elastic cornea and sclera and the vitreous body. The results showed a significant rise of the resonance-frequencies with increasing IOP. This shift is enlarging for higher modes. In parallel measurements were performed on artificial eyes and on enucleated pig eyes to prove this correlation experimentally. A measuring system existing of a transducer to excite the bulbus, a miniaturized laser-vibrometer and PC was built. The eyes were stimulated both contacting the eye with a transducer by a stick and contactless with sonic waves. Several series of measurements were done to examine the pressure dependency of the acoustic behavior. The measurements showed a proportional constant of 1.25 Hz/mmHg in average, which can be detected easily. The standard deviation measuring different pig eyes was 4.5 mmHg.

  5. [Learning curve in laser treatment of benign prostatic syndrome: a systematic review].

    PubMed

    Rasch, Andrej; Gruber, Sabine; Perleth, Matthias

    2013-01-01

    The aim of the present systematic review was to evaluate the evidence of a potential learning curve for laser treatment of benign prostatic hyperplasia. A systematic literature search was conducted in November 2011 using The Cochrane Library, EMBASE and MEDLINE. Overall, 18 sources (mostly case series) were included for further assessment. The majority of publications assume that a general learning curve exists. It is estimated that a range of 20 to 50 cases is needed to achieve a stable outcome level. For the most part, these findings are based on the HoLEP (Holmium laser enucleation of prostate) technique and intraoperative measures, such as enucleation efficiency. Valid conclusions regarding patient-related end-points are difficult to make, although some studies report a decreasing trend for complication rates with increasing experience of the surgeon. No statistically significant differences were found for postoperative outcomes such as IPSS (International Prostate Symptom Score), Qmax (peak flow rate) or Quality of Life. Overall, the present results are highly limited by the low evidence level and methodological problems of the publications available. Several publications suggest that adequate training during the implementation phase is relevant.

  6. Microscopic analysis of structural changes in diode-laser-welded corneal stroma

    NASA Astrophysics Data System (ADS)

    Matteini, Paolo; Rossi, Francesca; Menabuoni, Luca; Pini, Roberto

    2007-02-01

    Diode laser welding of the cornea is a technique used to provide immediate sealing of corneal wounds: the cut is stained with a water solution of Indocyanine Green and is then irradiated with an 810 nm laser at low power densities (12-16 W/cm2), which induces a localized heating of the stroma in the range 55-66 °C range. In this study, we present a microscopic analysis aimed at evaluating the structural modifications induced in the stromal collagen of pig eyes during the laser welding of corneal wounds. Cornea samples obtained from twenty freshly-enucleated eyes were cut with a pre-calibrated knife and subjected to the laser welding procedure. Histological slices of the laser-welded stroma were examined by means of optical and transmission electron microscopy. These analyses indicated that bridges of lamellar structures crossed the wound edges with no presence of a coagulation effect. After laser welding, collagen fibrils appeared differently oriented among themselves in comparison with those of the control samples, but with similar mean fibril diameters. The laser-induced effect appeared to be confined to the ICG stained area of the cut walls, and no heat damage was observed at the operative power levels of laser corneal welding.

  7. Improved efficiency of microsurgical enucleated tripronuclear zygotes development and embryonic stem cell derivation by supplementing epidermal growth factor, brain-derived neurotrophic factor, and insulin-like growth factor-1.

    PubMed

    Fan, Yong; Li, Rong; Huang, Jin; Zhao, Hong-Cui; Ding, Ting; Sun, Xiaofang; Yu, Yang; Qiao, Jie

    2014-03-15

    Human embryonic stem cells (hESCs) hold great promise for future clinical cell therapies because of their unique potential to differentiate into all human cell types. However, the destruction of normal fertilized embryos and the derivation of hESCs for research has resulted in polarized ethical debates, with most of the controversy centered on embryo destruction. Therefore, due to less ethical controversy surrounding them, abnormal fertilized zygotes that are usually discarded are a potential feasible resource for the derivation of hESCs. Microsurgery on human polyspermic zygotes can contribute to the derivation of hESCs, but the efficiency is much lower. Here, we reported a culture system to enhance the developmental competence of such microsurgical human polyspermic zygotes by EGF-BDNF-IGF-1 combination, which eventually resulted in the increased derivation efficiency of hESCs from them. We found that the developmental efficiency of microsurgical enucleated tripronuclear (3PN) embryos cultured with the EGF-BDNF-IGF-1 combination was significantly increased compared with the control group. More importantly, when the microsurgical enucleated 3PN embryos were cultured in medium supplemented with EGF-BDNF-IGF-1, the frequency ratio of chromosome abnormality was reduced. Our present study will facilitate the development of hESC line derivation in subsequent studies and also provide an additional choice for infertile couples.

  8. High-Resolution In Vivo Imaging of Regimes of Laser Damage to the Primate Retina

    PubMed Central

    Pocock, Ginger M.; Oliver, Jeffrey W.; Specht, Charles S.; Estep, J. Scot; Noojin, Gary D.; Schuster, Kurt; Rockwell, Benjamin A.

    2014-01-01

    Purpose. To investigate fundamental mechanisms of regimes of laser induced damage to the retina and the morphological changes associated with the damage response. Methods. Varying grades of photothermal, photochemical, and photomechanical retinal laser damage were produced in eyes of eight cynomolgus monkeys. An adaptive optics confocal scanning laser ophthalmoscope and spectral domain optical coherence tomographer were combined to simultaneously collect complementary in vivo images of retinal laser damage during and following exposure. Baseline color fundus photography was performed to complement high-resolution imaging. Monkeys were perfused with 10% buffered formalin and eyes were enucleated for histological analysis. Results. Laser energies for visible retinal damage in this study were consistent with previously reported damage thresholds. Lesions were identified in OCT images that were not visible in direct ophthalmoscopic examination or fundus photos. Unique diagnostic characteristics, specific to each damage regime, were identified and associated with shape and localization of lesions to specific retinal layers. Previously undocumented retinal healing response to blue continuous wave laser exposure was recorded through a novel experimental methodology. Conclusion. This study revealed increased sensitivity of lesion detection and improved specificity to the laser of origin utilizing high-resolution imaging when compared to traditional ophthalmic imaging techniques in the retina. PMID:24891943

  9. High-resolution in vivo imaging of regimes of laser damage to the primate retina.

    PubMed

    Pocock, Ginger M; Oliver, Jeffrey W; Specht, Charles S; Estep, J Scot; Noojin, Gary D; Schuster, Kurt; Rockwell, Benjamin A

    2014-01-01

    Purpose. To investigate fundamental mechanisms of regimes of laser induced damage to the retina and the morphological changes associated with the damage response. Methods. Varying grades of photothermal, photochemical, and photomechanical retinal laser damage were produced in eyes of eight cynomolgus monkeys. An adaptive optics confocal scanning laser ophthalmoscope and spectral domain optical coherence tomographer were combined to simultaneously collect complementary in vivo images of retinal laser damage during and following exposure. Baseline color fundus photography was performed to complement high-resolution imaging. Monkeys were perfused with 10% buffered formalin and eyes were enucleated for histological analysis. Results. Laser energies for visible retinal damage in this study were consistent with previously reported damage thresholds. Lesions were identified in OCT images that were not visible in direct ophthalmoscopic examination or fundus photos. Unique diagnostic characteristics, specific to each damage regime, were identified and associated with shape and localization of lesions to specific retinal layers. Previously undocumented retinal healing response to blue continuous wave laser exposure was recorded through a novel experimental methodology. Conclusion. This study revealed increased sensitivity of lesion detection and improved specificity to the laser of origin utilizing high-resolution imaging when compared to traditional ophthalmic imaging techniques in the retina.

  10. Corneal photoablation in vivo with the erbium:YAG laser: first report

    NASA Astrophysics Data System (ADS)

    Jean, Benedikt J.; Bende, Thomas; Matallana, Michael; Kriegerowski, Martin

    1995-05-01

    As an alternative to far-UV lasers for corneal refractive surgery, the Erbium:YAG laser may be used in TEM00 mode. The resulting gaussian beam profile leads to a certain amount of myopic correction per laser pulse. Although animal data suggest that the clinical outcome should be comparable to the UV-lasers, no human data were available until now. We performed Erbium:YAG laser areal ablation in 5 blind human eyes. In TEM00 mode, the laser parameters were: effective diameter of laser spot equals 3.4 mm, fluence equals 380 mJ/cm2, pulse duration equals 250 microsecond(s) , Repetition rate equals 4 Hz, Number of applied laser pulses equals 15. Four patients with no light perception, one with intact light projection on one eye (some of them scheduled for enucleation) were treated under topical anaesthesia. Patient selection and informed consent were agreed to by the University's independent Ethics Committee. Prior to laser irradiation, corneal epithelium was removed. A postoperative silicone cast of the cornea was analyzed with a confocal laser micro-topometer for the ablation profile. The eyes were treated with antibiotic ointment until the epithelium was closed. Clinical appearance and, where possible, profilometry of the ablated area was observed. The ablation profile in cornea was gaussian shaped with a maximal depth of 30 micrometers . During laser treatment, the corneal surface becomes opaque, clearing in a matter of seconds. Epithelial healing and clinical appearance was similar to excimer laser treatment. However, during the first week, the irradiated area shows subepithelial irregularities, resembling small bubbles, disappearing thereafter.

  11. Laser clock

    SciTech Connect

    Facklam, R.L.

    1983-05-26

    A laser clock includes a linear laser in one embodiment of the clock and a ring laser gyro in the other embodiment. The linear laser is frequency stabilized and utilizes a single active medium in the form of a low pressure gas, such as He-Ne, with a Doppler broadened gain curve. The ring laser gyro is a four frequency laser with a Faraday rotor. Detector and electronic circuitry associated with the laser of each embodiment detects a beat frequency and convert it to a clock signal.

  12. Blue Laser.

    DTIC Science & Technology

    1985-12-01

    HOLLOW CATHODE LASER FABRICATION 13 4. EXPERIENCE WITH THE BLUE LASER 18 4.1 Operational and Processing Experience 18 4.2 Performance Testing 20 5...34 -. - . •. SECTION 3 BLUE HOLLOW CATHODE LASER FABRICATION This section presents an overview of the steps taken in creating a HCL. There is...to the laser assembly. These steps can actually be considered as the final steps in laser fabrication because some of them involve adding various

  13. Laser speckle tracking for monitoring and analysis of retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Seifert, Eric; Bliedtner, Katharina; Brinkmann, Ralf

    2014-02-01

    Laser coagulation of the retina is an established treatment for several retinal diseases. The absorbed laser energy and thus the induced thermal damage varies with the transmittance and scattering properties of the anterior eye media and with the pigmentation of the fundus. The temperature plays the most important role in the coagulation process. An established approach to measure a mean retinal temperature rise is optoacoustics, however it provides limited information on the coagulation. Phase sensitive OCT potentially offers a three dimensional temporally resolved temperature distribution but is very sensitive to slightest movements which are clinically hard to avoid. We develop an optical technique able to monitor and quantify thermally and coagulation induced tissue movements (expansions and contractions) and changes in the tissue structure by dynamic laser speckle analysis (LSA) offering a 2D map of the affected area. A frequency doubled Nd:YAG laser (532nm) is used for photocoagulation. Enucleated porcine eyes are used as targets. The spot is 100μm. A Helium Neon laser (HeNe) is used for illumination. The backscattered light of a HeNe is captured with a camera and the speckle pattern is analyzed. A Q-switched Nd:YLF laser is used for simultaneous temperature measurements with the optoacoustic approach. Radial tissue movements in the micrometer regime have been observed. The signals evaluation by optical flow algorithms and generalized differences tuned out to be able to distinguish between regions with and without immediate cell damage. Both approaches have shown a sensitivity of 93% and a specificity above 99% at their optimal threshold.

  14. Lasers of All Sizes

    NASA Astrophysics Data System (ADS)

    Balcou, Philippe; Forget, Sébastien Robert-Philip, Isabelle

    2015-10-01

    * Introduction * The Laser in All Its Forms * Gas lasers * Dye lasers * Solid-state lasers * Lasers for Every Taste * The rise of lasers * Lasers of all sizes * The colors of the rainbow... and beyond * Shorter and shorter lasers * Increasingly powerful lasers * Lasers: A Universal Tool? * Cutting, welding, and cleaning * Communicating * Treating illnesses * Measuring * Supplying energy? * Entertaining * Understanding * Conclusion

  15. Laser microphone

    DOEpatents

    Veligdan, James T.

    2000-11-14

    A microphone for detecting sound pressure waves includes a laser resonator having a laser gain material aligned coaxially between a pair of first and second mirrors for producing a laser beam. A reference cell is disposed between the laser material and one of the mirrors for transmitting a reference portion of the laser beam between the mirrors. A sensing cell is disposed between the laser material and one of the mirrors, and is laterally displaced from the reference cell for transmitting a signal portion of the laser beam, with the sensing cell being open for receiving the sound waves. A photodetector is disposed in optical communication with the first mirror for receiving the laser beam, and produces an acoustic signal therefrom for the sound waves.

  16. Laser ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    2004-01-13

    Sequenced pulses of light from an excitation laser with at least two resonator cavities with separate output couplers are directed through a light modulator and a first polarzing analyzer. A portion of the light not rejected by the first polarizing analyzer is transported through a first optical fiber into a first ignitor laser rod in an ignitor laser. Another portion of the light is rejected by the first polarizing analyzer and directed through a halfwave plate into a second polarization analyzer. A first portion of the output of the second polarization analyzer passes through the second polarization analyzer to a second, oscillator, laser rod in the ignitor laser. A second portion of the output of the second polarization analyzer is redirected by the second polarization analyzer to a second optical fiber which delays the beam before the beam is combined with output of the first ignitor laser rod. Output of the second laser rod in the ignitor laser is directed into the first ignitor laser rod which was energized by light passing through the first polarizing analyzer. Combined output of the first ignitor laser rod and output of the second optical fiber is focused into a combustible fuel where the first short duration, high peak power pulse from the ignitor laser ignites the fuel and the second long duration, low peak power pulse directly from the excitation laser sustains the combustion.

  17. Laser sampling

    NASA Astrophysics Data System (ADS)

    Gorbatenko, A. A.; Revina, E. I.

    2015-10-01

    The review is devoted to the major advances in laser sampling. The advantages and drawbacks of the technique are considered. Specific features of combinations of laser sampling with various instrumental analytical methods, primarily inductively coupled plasma mass spectrometry, are discussed. Examples of practical implementation of hybrid methods involving laser sampling as well as corresponding analytical characteristics are presented. The bibliography includes 78 references.

  18. Use of picosecond infrared laser for micromanipulation of early mammalian embryos.

    PubMed

    Karmenyan, Artashes V; Shakhbazyan, Avetik K; Sviridova-Chailakhyan, Tatiana A; Krivokharchenko, Alexander S; Chiou, Arthur E; Chailakhyan, Levon M

    2009-10-01

    A high repetition rate (80 MHz) picosecond pulse (approximately 2 psec) infrared laser was used for the inactivation (functional enucleation) of oocytes and two-cell mouse embryos and also for the fusion of blastomeres of two-cell mouse embryos. The laser inactivation of both blastomeres of two-cell mouse embryos by irradiation of nucleoli completely blocked further development of the embryo. The inactivation of one blastomere, however, did not affect the ability of the second intact blastomere to develop into a blastocyst after treatment. Laser inactivation of oocytes at Metaphase II (MII) stage and parthenogenetically activated pronuclear oocytes also completely blocked their ability for further development. Suitable doses of irradiation in cytoplasm region did not affect the ability of embryos and activated oocytes to development. The efficiency of laser induced fusion for blastomeres of two-cell embryos was 66.7% and all the tetraploid embryos developed successfully into blastocysts in culture. Our results demonstrate unique opportunities of the applications of a suitable infrared periodic pulse laser as a universal microsurgery tool for individual living cells.

  19. CW laser pumped emerald laser

    SciTech Connect

    Shand, M.L.; Lai, S.T.

    1984-02-01

    A CW laser-pumped emerald laser is reported. A 34 percent output power slope efficiency is observed with longitudinal pumping by a krypton laser in a nearly concentric cavity. The laser has been tuned from 728.8 to 809.0 nm. Losses in emerald are larger than those of alexandrite determined in a similar cavity. The present data also indicate that the excited state absorption minimum is shifted from that of alexandrite. 13 references.

  20. Laser device

    DOEpatents

    Scott, Jill R.; Tremblay, Paul L.

    2007-07-10

    A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

  1. Laser device

    DOEpatents

    Scott, Jill R.; Tremblay, Paul L.

    2004-11-23

    A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

  2. Laser ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    2003-01-01

    In the apparatus of the invention, a first excitation laser or other excitation light source is used in tandem with an ignitor laser to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using a single remote excitation light source for one or more small lasers located proximate to one or more fuel combustion zones. In a third embodiment, alternating short and long pulses of light from the excitation light source are directed into the ignitor laser. Each of the embodiments of the invention can be multiplexed so as to provide laser light energy sequentially to more than one ignitor laser.

  3. Biocavity Lasers

    SciTech Connect

    Gourley, P.L.; Gourley, M.F.

    2000-10-05

    Laser technology has advanced dramatically and is an integral part of today's healthcare delivery system. Lasers are used in the laboratory analysis of human blood samples and serve as surgical tools that kill, burn or cut tissue. Recent semiconductor microtechnology has reduced the size o f a laser to the size of a biological cell or even a virus particle. By integrating these ultra small lasers with biological systems, it is possible to create micro-electrical mechanical systems that may revolutionize health care delivery.

  4. Laser apparatus

    DOEpatents

    Lewis, Owen; Stogran, Edmund M.

    1980-01-01

    Laser apparatus is described wherein an active laser element, such as the disc of a face-pumped laser, is mounted in a housing such that the weight of the element is supported by glass spheres which fill a chamber defined in the housing between the walls of the housing and the edges of the laser element. The uniform support provided by the spheres enable the chamber and the pump side of the laser element to be sealed without affecting the alignment or other optical properties of the laser element. Cooling fluid may be circulated through the sealed region by way of the interstices between the spheres. The spheres, and if desired also the cooling fluid may contain material which absorbs radiation at the wavelength of parasitic emissions from the laser element. These parasitic emissions enter the spheres through the interface along the edge surface of the laser element and it is desirable that the index of refraction of the spheres and cooling fluid be near the index of refraction of the laser element. Thus support, cooling, and parasitic suppression functions are all accomplished through the use of the arrangement.

  5. Laser ignition

    DOEpatents

    Early, James W.; Lester, Charles S.

    2002-01-01

    In the apparatus of the invention, a first excitation laser or other excitation light source capable of producing alternating beams of light having different wavelengths is used in tandem with one or more ignitor lasers to provide a compact, durable, engine deployable fuel ignition laser system. Reliable fuel ignition is provided over a wide range of fuel conditions by using the single remote excitation light source for pumping one or more small lasers located proximate to one or more fuel combustion zones with alternating wavelengths of light.

  6. New semiconductor diode laser emitting at 2 um for microsurgery applications

    NASA Astrophysics Data System (ADS)

    Gobbi, Pier Giorgio; Ragazzi, D.; Azzolini, Claudio; Trabucchi, Giuseppe; Brancato, Rosario

    1996-01-01

    A surgical laser instrument is presented, based on a semiconductor diode emitting in the spectral region around 2 micrometer, in continuous mode. At this wavelength tissue absorption is via histological water, and the interaction is purely thermal. A portable laser station was built, emitting up to 250 mW of optical power at 1.94 micrometers, out of the tip of a low- hydroxil fused-silica optical fiber of 200 micrometer diameter. Experiments have been performed both in vitro with enucleated porcine eyes and in vivo, on rabbits and rats. In vitreo-retinal surgery, retinectomies and incisions of epiretinal fibrotic membranes have been achieved. At reduced output power the laser radiation has been applied to the welding of tissues, in particular cornea, sclera and skin, with interesting results. This new laser source, characterized by ergonomic advantages like compactness, portability, long lifetime, reduced maintenance, is potentially attractive for a number of microsurgical procedures like micro- incisions, shallow coagulations, and welding of hydrated biological membranes.

  7. Fs-laser induced elasticity changes to improve presbyopic lens accommodation

    NASA Astrophysics Data System (ADS)

    Ripken, T.; Oberheide, U.; Ziltz, C.; Ertmer, W.; Gerten, G.; Lubatschowski, H.

    2005-04-01

    According to Helmholtz' theory of accommodation one of the mayor reasons for the development of presbyopia is the increasing sclerosis of the lens. One concept to delay the process of sclerosis or even regain the deformation ability of the lens might be the treatment of the lens by femtosecond laser pulses. Our aim was to evaluate appropriate laser parameters for this possible treatment and to analyse potential changes in deformation ability of the treated lenses. We performed different cutting patterns in enucleated pig lenses (ex vivo) using the disruptive effect of an ultrafast near-infrared laser induced optical breakdown. Pulse energies and spot separation of the laser pulses were varied to investigate the effect on the generated cut. For an evaluation of the gain in deformation ability the lenses were rotated before and after treatment and the changes in lens thickness due to centrifugal forces were measured. In result, a smooth cutting was possible with appropriate parameters. The experiments showed an increase of elasticity in 70% of the eyes. When the lenses were treated more statistically, an average deformation ability increase of nearly 20%, determined by the change of thickness between untreated and treated lens, was measured.

  8. Laser welding of chitosan-GNRs films for the closure of a capsulorhexis

    NASA Astrophysics Data System (ADS)

    Rossi, Francesca; Matteini, Paolo; Ratto, Fulvio; Menabuoni, Luca; Lenzetti, Ivo; Pini, Roberto

    2011-03-01

    In this work we present the first attempt to close the anterior lens capsule bag by the use of chitosan patches, where Gold Nanorods (GNRs) are embedded. GNRs exhibit intense localized plasmon resonances at optical frequencies in the near infrared (NIR): upon excitation with a NIR laser, a strong photothermal effect is produced, which can be exploited to develop minimally invasive therapies. Here we use the chitosan-GNRs films as a novel NIR sensitive nanocomposite for the photothermal conversion of NIR laser light during surgical interventions of tissue welding. Chitosan is an attractive biomaterial due to its biodegradability, biocompatibility, antimicrobial and wound healing-promoting activity. Colloidal GNRs were embedded in chitosan based, highly stabilized, flexible and easy-to-handle films, which were stored in water until the time of surgery. In these preliminary tests, a capsulorhexis was performed in freshly enucleated porcine eyes. The lens was aspired, then the patch was put onto the capsule bag and welded: a diode laser (810 nm) was used to deliver single spots (200 μm core diameter optical fiber) of local capsule/patch adhesion. Then the bag was refilled with silicon oil. The result is an immediate closure of the capsular tissue, with high mechanical strength. The laser welded chitosan- GNRs films are an innovative and highly stable solution to be exploited for the treatment of capsular breaks and for the implementation of a lens refilling procedure.

  9. Morphologic evaluations of Q-switched Nd:YAG laser injury of human retina

    NASA Astrophysics Data System (ADS)

    Scales, David K.; Schuschereba, Steven T.; Lund, David J.; Stuck, Bruce E.

    1997-05-01

    Depiction of the cellular and immune responses in the human model is critical to design rational therapies preventing/limiting cellular destruction and ultimately functional visual loss following acute laser injuries. We report the light and electron microscopy histologic findings in a controlled ocular human laser exposure. Following informed consent, the normal eye of a patient scheduled to undergo exenteration for invasive carcinoma of the orbit was exposed to both continuous wave and Q-switched lasers. Four hours prior to exenteration, argon G lesions were placed in the superior/temporal quadrant and Nd:YAG lesions were placed in the inferior/temporal quadrant. After enucleation, the retina was prepared for routine light and transmission electron microscopy. Histology of the argon G lesions showed primarily photoreceptor and RPE photocoagulation damage. Neutrophil adhesion was limited within the choroid and no neutrophils were observed in the subretinal space. In contrast, the 4 hr Nd:YAG lesions showed extensive retinal disruption, hemorrhage within subretinal and intraretinal spaces, neutrophil accumulation in the retina, and an extensive neutrophil chemotaxic and emigration response in the choroid. Severe laser injuries elicit a significant neutrophil response by 4 hr, suggesting that neutrophils should be an early stage therapeutic target.

  10. Multimegajoule laser design. [Glass lasers

    SciTech Connect

    Manes, K.R.; Ozarski, R.G.; Hagen, W.F.; Holzrichtr, J.F.

    1985-08-01

    New technologies make multimegajoule glass lasers economically feasible. We have devised new laser architectures using harmonic switchout, target-plane holographic injection, phase conjugation, continuous apodization, and higher amplifier efficiencies. Our plan for building a multimegajoule laser for a recurring cost under $300 million relies on the following manufacturing economies of scale: high-volume glass production, rapid harmonic-crystal growth, capacitor sizing and packing to increase energy capacity, and part standardization.

  11. Heterodyne laser spectroscopy system

    DOEpatents

    Wyeth, Richard W.; Paisner, Jeffrey A.; Story, Thomas

    1989-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency and the like, and provides spectral analysis of a laser beam.

  12. Heterodyne laser spectroscopy system

    DOEpatents

    Wyeth, Richard W.; Paisner, Jeffrey A.; Story, Thomas

    1990-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency, and provides spectral analysis of a laser beam.

  13. Co Laser.

    DTIC Science & Technology

    1976-01-01

    newsletter setvice covering the moj-t recent research findings in 25 areas of industrial, technological , and sociological interest— invaluable information...service will be backdated to furnish you microfiche of reports issued earlier. Because of contractual arrangements with several Special Technology ...pressure electrical CO laser and, thereby, to develop the technology for high pres- sure, scalable, electric CO lasers exhibiting properties of

  14. Laser device

    DOEpatents

    Scott, Jill R.; Tremblay, Paul L.

    2008-08-19

    A laser device includes a virtual source configured to aim laser energy that originates from a true source. The virtual source has a vertical rotational axis during vertical motion of the virtual source and the vertical axis passes through an exit point from which the laser energy emanates independent of virtual source position. The emanating laser energy is collinear with an orientation line. The laser device includes a virtual source manipulation mechanism that positions the virtual source. The manipulation mechanism has a center of lateral pivot approximately coincident with a lateral index and a center of vertical pivot approximately coincident with a vertical index. The vertical index and lateral index intersect at an index origin. The virtual source and manipulation mechanism auto align the orientation line through the index origin during virtual source motion.

  15. Evaluation of Color-Changing Effect and Complications After Nd: YAG Laser Application On Iris Surface

    PubMed Central

    Yildirim, Yildiray; Duzgun, Eyup; Kar, Taner; Sonmez, Murat; Kucukodaci, Zafer; Ersanli, Dilaver; Basoglu, Ayhan

    2016-01-01

    Background The aim of this study was to evaluate the color-changing effect and adverse effects after Nd: YAG laser application on the iris surface of rabbit eyes. Material/Methods The study was performed on right eyes of 12 pigmented rabbits. A laser device that produces frequency doubled 532 nm wavelength Nd: YAG laser with 900 μm spot diameter was used. The laser was applied in 3 sessions at 2-week intervals, at energy levels of 0.8 mJ in Group A and 1.5 mJ in Group B. Slit-lamp examinations and measurements of intraocular pressure (IOP) using a Tono-Pen were performed before and 1 day after each laser session. Iris thickness (IT) was measured at the beginning and the end using an ultrasonic biomicroscope. The eyes were enucleated for histopathologic examination on day 60. Results On the first day after each laser session, maximum grade 1 anterior chamber flare and cells were observed in both groups. In all eyes, flare and cells disappeared at the end of the first week. There was no significant difference in the IOP and IT values between measurements performed prior to and after laser sessions during the study (p>0.05). None of the eyes showed complications such as corneal edema, hypopyon, posterior synechia, transillumination defect, or pupillary defect. In histopathological examinations, reduction in pigment density was more profound in Group B compared to Group A, which was statistically significant (p<0.019). Conclusions There were no serious complications apart from mild transient inflammatory signs. Change in iris color was more evident at the end of the second month. PMID:26751845

  16. High throughput laser processing

    SciTech Connect

    Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

    2016-12-27

    A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

  17. Laser goniometer

    DOEpatents

    Fairer, George M.; Boernge, James M.; Harris, David W.; Campbell, DeWayne A.; Tuttle, Gene E.; McKeown, Mark H.; Beason, Steven C.

    1993-01-01

    The laser goniometer is an apparatus which permits an operator to sight along a geologic feature and orient a collimated lamer beam to match the attitude of the feature directly. The horizontal orientation (strike) and the angle from horizontal (dip), are detected by rotary incremental encoders attached to the laser goniometer which provide a digital readout of the azimuth and tilt of the collimated laser beam. A microprocessor then translates the square wave signal encoder outputs into an ASCII signal for use by data recording equipment.

  18. Laser propulsion

    NASA Technical Reports Server (NTRS)

    Rom, F. E.; Putre, H. A.

    1972-01-01

    The use of an earth-based high-power laser beam to provide energy for earth-launched rocket vehicle is investigated. The laser beam energy is absorbed in an opaque propellant gas and is converted to high-specific-impulse thrust by expanding the heated propellant to space by means of a nozzle. This laser propulsion scheme can produce specific impulses of several thousand seconds. Payload to gross-weight fractions about an order of magnitude higher than those for conventional chemical earth-launched vehicles appear possible. There is a potential for a significant reduction in cost per payload mass in earth orbit.

  19. Explosive laser

    DOEpatents

    Robinson, C.P.; Jensen, R.J.; Davis, W.C.; Sullivan, J.A.

    1975-09-01

    This patent relates to a laser system wherein reaction products from the detonation of a condensed explosive expand to form a gaseous medium with low translational temperature but high vibration population. Thermal pumping of the upper laser level and de-excitation of the lower laser level occur during the expansion, resulting in a population inversion. The expansion may be free or through a nozzle as in a gas-dynamic configuration. In one preferred embodiment, the explosive is such that its reaction products are CO$sub 2$ and other species that are beneficial or at least benign to CO$sub 2$ lasing. (auth)

  20. Bipolar transurethral enucleation and resection of the prostate versus bipolar resection of the prostate for prostates larger than 60gr: A retrospective study at a single academic tertiary care center

    PubMed Central

    Wei, Yong; Xu, Ning; Chen, Shao-Hao; Li, Xiao-Dong; Zheng, Qing-Shui; Lin, Yun-Zhi; Xue, Xue-Yi

    2016-01-01

    ABSTRACT Objective: To evaluate the efficacy and safety of bipolar transurethral enucleation and resection of the prostate (B-TUERP) versus bipolar transurethral resection of the prostate (B-TURP) in the treatment of prostates larger than 60g. Material and Methods: Clinical data for 270 BPH patients who underwent B-TUERP and 204 patients who underwent B-TURP for BPH from May 2007 to May 2013 at our center were retrospectively analyzed. Outcome measures included operative time, decreased hemoglobin level, total prostate specific antigen (TPSA), International Prostate Symptom Score (IPSS), maximal urinary flow rate (Qmax), quality of life (QoL) score, post void residual urine volume (RUV), bladder irrigation duration, hospital stay, and the weight of resected prostatic tissue. Other measures included perioperative complications including transurethral resection syndrome (TURS), hyponatremia, blood transfusion, bleeding requiring surgery, postoperative acute urinary retention, urine incontinence and urinary sepsis. Patients in both groups were followed for two years. Results: Compared with the B-TURP group, the B-TUERP group had shorter operative time, postoperative bladder irrigation duration and hospital stay, a greater amount of resected prostatic tissue, less postoperative hemoglobin decrease, better postoperative IPSS and Qmax, as well as lower incidences of hyponatremia, urinary sepsis, blood transfusion requirement, urine incontinence and reoperation (P<0.05 for all). Conclusions: B-TUERP is superior to B-TURP in the management of large volume BPH in terms of efficacy and safety, but this finding needs to be validated in further prospective, randomized, controlled studies. PMID:27564286

  1. [Laser myringotomy].

    PubMed

    Hassmann-Poznańska, Elzbieta; Skotnicka, Bozena

    2002-01-01

    The aim of the study was assessment of the qualities of laser-assisted myringotomy (LAM) as a treatment for acute and secretory otitis media. Laser-assisted myringotomy was performed on 65 children (113 ears) mean age 6.2 years diagnosed with secretory otitis media (80%), recurrent secretory otitis media (11%) and acute otitis media (9%). Myringotomy was performed under general anesthesia using the OtoLAM device (ESC/Sharplan, Israel). In 64 ears pressure equalisation tubes were inserted after fenestration of the tympanic membrane with laser. Adenoidectomy alone or with tonsillectomy was performed at the same time in 51 cases. Laser tympanostomies remained patent for 7-32 days. All tympanostomies healed with no noticeable scarring. LAM appears to be a safe, and easy to performed, alternative technique in the treatment of otitis media.

  2. Laser fusion

    SciTech Connect

    Smit, W.A.; Boskma, P.

    1980-12-01

    Unrestricted laser fusion offers nations an opportunity to circumvent arms control agreements and develop thermonuclear weapons. Early laser weapons research sought a clean radiation-free bomb to replace the fission bomb, but this was deceptive because a fission bomb was needed to trigger the fusion reaction and additional radioactivity was induced by generating fast neutrons. As laser-implosion experiments focused on weapons physics, simulating weapons effects, and applications for new weapons, the military interest shifted from developing a laser-ignited hydrogen bomb to more sophisticated weapons and civilian applications for power generation. Civilian and military research now overlap, making it possible for several countries to continue weapons activities and permitting proliferation of nuclear weapons. These countries are reluctant to include inertial confinement fusion research in the Non-Proliferation Treaty. 16 references. (DCK)

  3. Laser barometer

    SciTech Connect

    Abercrombie, K.R.; Shiels, D.; Rash, T.

    1998-04-01

    This paper describes an invention of a pressure measuring instrument which uses laser radiation to sense the pressure in an enclosed environment by means of measuring the change in refractive index of a gas - which is pressure dependent.

  4. Laser Cutting

    DTIC Science & Technology

    1988-06-01

    lasers that are optically modified to produce high beam quality at reduced power levels for precision drilling and trepanning. * Nd:YAG lasers with...a smooth, dross-free cut face while the marking consists of a series of precisely placed shallow pits where surface finish and dross are not usually...neodymium:yttrium-aluminum-garnet (Nd:YAG) pulsed cutting data because the technique is considered vital in meeting the detailed precision cutting

  5. Laser Technology

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Amoco Laser Company, a subsidiary of Amoco Corporation, has developed microlasers for the commercial market based on a JPL concept for optical communications over interplanetary distances. Lasers emit narrow, intense beams of light or other radiation. The beams transmit communication signals, drill, cut or melt materials or remove diseased body tissue. The microlasers cover a broad portion of the spectrum, and performance is improved significantly. Current applications include medical instrumentation, color separation equipment, telecommunications, etc.

  6. Laser Angioplasty

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The principal method of dealing with coronary artery blockage is bypass surgery. A non-surgical alternative available to some patients is balloon angioplasty. For several years, medical researchers have been exploring another alternative that would help a wider circle of patients than the balloon treatment and entail less risk than bypass surgery. A research group is on the verge of an exciting development: laser angioplasty with a 'cool' type of laser, called an excimer laser, that does not damage blood vessel walls and offers non-surgical cleansing of clogged arteries with extraordinary precision. The system is the Dymer 200+ Excimer Laser Angioplasty System, developed by Advanced Intraventional Systems. Used in human clinical tests since 1987, the system is the first fully integrated 'cool' laser capable of generating the requisite laser energy and delivering the energy to target arteries. Thirteen research hospitals in the U.S. have purchased Dymer 200+ systems and used them in clinical trials in 121 peripheral and 555 coronary artery cases. The success rate in opening blocked coronary arteries is 85 percent, with fewer complications than in balloon angioplasty. Food and Drug Administration approval for the system is hoped for in the latter part of 1990. * Advanced Intraventional Systems became Spectranetics in 1994 and discontinued the product.

  7. Laser optomechanics

    PubMed Central

    Yang, Weijian; Adair Gerke, Stephen; Wei Ng, Kar; Rao, Yi; Chase, Christopher; Chang-Hasnain, Connie J.

    2015-01-01

    Cavity optomechanics explores the interaction between optical field and mechanical motion. So far, this interaction has relied on the detuning between a passive optical resonator and an external pump laser. Here, we report a new scheme with mutual coupling between a mechanical oscillator supporting the mirror of a laser and the optical field generated by the laser itself. The optically active cavity greatly enhances the light-matter energy transfer. In this work, we use an electrically-pumped vertical-cavity surface-emitting laser (VCSEL) with an ultra-light-weight (130 pg) high-contrast-grating (HCG) mirror, whose reflectivity spectrum is designed to facilitate strong optomechanical coupling, to demonstrate optomechanically-induced regenerative oscillation of the laser optomechanical cavity. We observe >550 nm self-oscillation amplitude of the micromechanical oscillator, two to three orders of magnitude larger than typical, and correspondingly a 23 nm laser wavelength sweep. In addition to its immediate applications as a high-speed wavelength-swept source, this scheme also offers a new approach for integrated on-chip sensors. PMID:26333804

  8. Laser Physics and Laser Spectroscopy.

    DTIC Science & Technology

    1986-03-01

    effect which limits the power throughout of a device; terbium qallium garnet (TGG), a Faraday isolator material; potassium niobate (KNbO 31 a nonlinear...extending the range of materials grown in fiber form. Two materials to be emphasized are terbium gallium garnet for optical isolators and potassium niobate...for doubling gallium arsenide diode lasers. References 1. R.H. Stolen, "Fiber Raman Lasers", Fiber and Integrated Optics, 3 (1980). 2. E. Ipoen and

  9. Laser therapy for cancer

    MedlinePlus

    ... this page: //medlineplus.gov/ency/patientinstructions/000905.htm Laser therapy for cancer To use the sharing features ... Lasers are also used on the skin. How Laser Therapy is Used Laser therapy can be used ...

  10. Laser beam monitoring system

    DOEpatents

    Weil, Bradley S.; Wetherington, Jr., Grady R.

    1985-01-01

    Laser beam monitoring systems include laser-transparent plates set at an angle to the laser beam passing therethrough and light sensor for detecting light reflected from an object on which the laser beam impinges.

  11. Laser Physics and Laser-Tissue Interaction

    PubMed Central

    Welch, A. J.; Torres, Jorge H.; Cheong, Wai-Fung

    1989-01-01

    Within the last few years, lasers have gained increasing use in the management of cardiovascular disease, and laser angioplasty has become a widely performed procedure. For this reason, a basic knowledge of lasers and their applications is essential to vascular surgeons, cardiologists, and interventional radiologists. To elucidate some fundamental concepts regarding laser physics, we describe how laser light is generated and review the properties that make lasers useful in medicine. We also discuss beam profile and spotsize, as well as dosimetric specifications for laser angioplasty. After considering laser-tissue interaction and light propagation in tissue, we explain how the aforementioned concepts apply to direct laser angioplasty and laser-balloon angioplasty. An understanding of these issues should prove useful not only in performing laser angioplasty but in comparing the reported results of various laser applications. (Texas Heart Institute Journal 1989;16:141-9) PMID:15227198

  12. Laser acceleration

    NASA Astrophysics Data System (ADS)

    Tajima, T.; Nakajima, K.; Mourou, G.

    2017-02-01

    The fundamental idea of Laser Wakefield Acceleration (LWFA) is reviewed. An ultrafast intense laser pulse drives coherent wakefield with a relativistic amplitude robustly supported by the plasma. While the large amplitude of wakefields involves collective resonant oscillations of the eigenmode of the entire plasma electrons, the wake phase velocity ˜ c and ultrafastness of the laser pulse introduce the wake stability and rigidity. A large number of worldwide experiments show a rapid progress of this concept realization toward both the high-energy accelerator prospect and broad applications. The strong interest in this has been spurring and stimulating novel laser technologies, including the Chirped Pulse Amplification, the Thin Film Compression, the Coherent Amplification Network, and the Relativistic Mirror Compression. These in turn have created a conglomerate of novel science and technology with LWFA to form a new genre of high field science with many parameters of merit in this field increasing exponentially lately. This science has triggered a number of worldwide research centers and initiatives. Associated physics of ion acceleration, X-ray generation, and astrophysical processes of ultrahigh energy cosmic rays are reviewed. Applications such as X-ray free electron laser, cancer therapy, and radioisotope production etc. are considered. A new avenue of LWFA using nanomaterials is also emerging.

  13. Laser construction

    SciTech Connect

    Martin, D.W.; Osterhage, R.J.; Summa, K.M.

    1989-02-14

    A laser device is described comprising an elongated laser medium of crystal material having a cylindrical shape modified to have a flat face formed on one side thereof, a highly heat conducting mounting member having a flat surface on a portion thereof, the medium being mounted on the mounting member with the flat face of the medium in face-to-face relation with the flat surface on the mounting member, a heat sink member having a surface for attaching the mounting member to, a pump source including an array of laser diodes each having opposite ends and positioned in side-by-side single file relation, a second highly heat conducting mounting member having a surface on which the array of laser diodes is positioned, the second mounting member being mounted on the heat sink member wherein the array of laser diodes are in substantial alignment with the axis of the medium along the side thereof opposite from the flat face of the medium.

  14. Tunable solid state lasers

    SciTech Connect

    Hammerling, R.; Budgor, A.B.; Pinto, A.

    1985-01-01

    This book presents the papers given at a conference on solid state lasers. Topics considered at the conference included transition-metal-doped lasers, line-narrowed alexandrite lasers, NASA specification, meteorological lidars, laser materials spectroscopy, laser pumped single pass gain, vibronic laser materials growth, crystal growth methods, vibronic laser theory, cross-fertilization through interdisciplinary fields, and laser action of color centers in diamonds.

  15. Laser cosmology

    NASA Astrophysics Data System (ADS)

    Chen, P.

    2014-05-01

    Recent years have witnessed tremendous progress in our understanding of the cosmos, which in turn points to even deeper questions to be further addressed. Concurrently the laser technology has undergone dramatic revolutions, providing exciting opportunity for science applications. History has shown that the symbiosis between direct observations and laboratory investigation is instrumental in the progress of astrophysics. We believe that this remains true in cosmology. Current frontier phenomena related to particle astrophysics and cosmology typically involve one or more of the following conditions: (1) extremely high energy events;(2) very high density, high temperature processes; (3) super strong field environments. Laboratory experiments using high intensity lasers can calibrate astrophysical observations, investigate underlying dynamics of astrophysical phenomena, and probe fundamental physics in extreme limits. In this article we give an overview of the exciting prospect of laser cosmology. In particular, we showcase its unique capability of investigating frontier cosmology issues such as cosmic accelerator and quantum gravity.

  16. Laser barometer

    DOEpatents

    Abercrombie, Kevin R.; Shiels, David; Rash, Tim

    2001-02-06

    A pressure measuring instrument that utilizes the change of the refractive index of a gas as a function of pressure and the coherent nature of a laser light to determine the barometric pressure within an environment. As the gas pressure in a closed environment varies, the index of refraction of the gas changes. The amount of change is a function of the gas pressure. By illuminating the gas with a laser light source, causing the wavelength of the light to change, pressure can be quantified by measuring the shift in fringes (alternating light and dark bands produced when coherent light is mixed) in an interferometer.

  17. Excimer lasers

    NASA Technical Reports Server (NTRS)

    Palmer, A. J.; Hess, L. D.; Stephens, R. R.

    1976-01-01

    A theoretical and experimental investigation into the possibility of achieving CW discharge pumped excimer laser oscillation is reported. Detailed theoretical modeling of capillary discharge pumping of the XeF and KXe and K2 excimer systems was carried out which predicted the required discharge parameters for reaching laser threshold on these systems. Capillary discharge pumping of the XeF excimer system was investigated experimentally. The experiments revealed a lower excimer level population density than predicted theoretically by about an order of magnitude. The experiments also revealed a fluorine consumption problem in the discharge in agreement with theory.

  18. Graviton laser

    NASA Astrophysics Data System (ADS)

    Landry, A.; Paranjape, M. B.

    2016-08-01

    We consider the possibility of creating a graviton laser. The lasing medium would be a system of contained, ultra cold neutrons. Ultra cold neutrons are a quantum mechanical system that interacts with gravitational fields and with the phonons of the container walls. It is possible to create a population inversion by pumping the system using the phonons. We compute the rate of spontaneous emission of gravitons and the rate of the subsequent stimulated emission of gravitons. The gain obtainable is directly proportional to the density of the lasing medium and the fraction of the population inversion. The applications of a graviton laser would be interesting.

  19. Laser Resonator

    NASA Technical Reports Server (NTRS)

    Harper, L. L. (Inventor)

    1983-01-01

    An optical resonator cavity configuration has a unitary mirror with oppositely directed convex and concave reflective surfaces disposed into one fold and concertedly reversing both ends of a beam propagating from a laser rod disposed between two total internal reflection prisms. The optical components are rigidly positioned with perpendicularly crossed virtual rooflines by a compact optical bed. The rooflines of the internal reflection prisms, are arranged perpendicularly to the axis of the laser beam and to the optical axes of the optical resonator components.

  20. Excimer lasers

    NASA Technical Reports Server (NTRS)

    Palmer, A. J.; Hess, L. D.; Stephens, R. R.; Pepper, D. M.

    1977-01-01

    The results of a two-year investigation into the possibility of developing continuous wave excimer lasers are reported. The program included the evaluation and selection of candidate molecular systems and discharge pumping techniques. The K Ar/K2 excimer dimer molecules and the xenon fluoride excimer molecule were selected for study; each used a transverse and capillary discharges pumping technique. Experimental and theoretical studies of each of the two discharge techniques applied to each of the two molecular systems are reported. Discharge stability and fluorine consumption were found to be the principle impediments to extending the XeF excimer laser into the continuous wave regime. Potassium vapor handling problems were the principal difficulty in achieving laser action on the K Ar/K2 system. Of the four molecular systems and pumping techniques explored, the capillary discharge pumped K Ar/K2 system appears to be the most likely candidate for demonstrating continuous wave excimer laser action primarily because of its predicted lower pumping threshold and a demonstrated discharge stability advantage.

  1. Laser Balancing

    NASA Astrophysics Data System (ADS)

    1981-01-01

    Mechanical Technology, Incorporated developed a fully automatic laser machining process that allows more precise balancing removes metal faster, eliminates excess metal removal and other operator induced inaccuracies, and provides significant reduction in balancing time. Manufacturing costs are reduced as a result.

  2. Laser Photochemistry.

    DTIC Science & Technology

    1981-07-01

    reaction due to decreased adsorption of the species on the catalytic surface. For example, i. . . 41 in the catalytic decomposition of formic acid ...over platinum (Ulmstead and Lin, 1978), the preexcitation of the gaseous formic acid molecules (by a 10 W/cm2 CW CO2 laser) resulted in a 50% increase...attention is given to selective and thermal excitation and the role of multiphonon couplings, heterogeneous catalysis , and chemical vapor deposition and

  3. Making a Laser Level

    ERIC Educational Resources Information Center

    Hawkins, Harry

    2004-01-01

    This article describes how to construct a laser level. This laser level can be made using a typical 4' (or shorter) bubble level and a small laser point. The laser unit is detachable, so the bubble level can also be used in the conventional way. However, the laser level works better than a simple bubble level. Making this inexpensive device is an…

  4. Infrared Lasers in Chemistry.

    ERIC Educational Resources Information Center

    John, Phillip

    1982-01-01

    Selected infrared laser chemistry topics are discussed including carbon dioxide lasers, infrared quanta and molecules, laser-induced chemistry, structural isomerization (laser purification, sensitized reactions, and dielectric breakdown), and fundamental principles of laser isotope separation, focusing on uranium isotope separation. (JN)

  5. Project LASER

    NASA Technical Reports Server (NTRS)

    1990-01-01

    NASA formally launched Project LASER (Learning About Science, Engineering and Research) in March 1990, a program designed to help teachers improve science and mathematics education and to provide 'hands on' experiences. It featured the first LASER Mobile Teacher Resource Center (MTRC), is designed to reach educators all over the nation. NASA hopes to operate several MTRCs with funds provided by private industry. The mobile unit is a 22-ton tractor-trailer stocked with NASA educational publications and outfitted with six work stations. Each work station, which can accommodate two teachers at a time, has a computer providing access to NASA Spacelink. Each also has video recorders and photocopy/photographic equipment for the teacher's use. MTRC is only one of the five major elements within LASER. The others are: a Space Technology Course, to promote integration of space science studies with traditional courses; the Volunteer Databank, in which NASA employees are encouraged to volunteer as tutors, instructors, etc; Mobile Discovery Laboratories that will carry simple laboratory equipment and computers to provide hands-on activities for students and demonstrations of classroom activities for teachers; and the Public Library Science Program which will present library based science and math programs.

  6. Laser nitriding and laser carburizing of surfaces

    NASA Astrophysics Data System (ADS)

    Schaaf, Peter

    2003-11-01

    Laser irradiation of surfaces with short pulses in reactive atmospheres (nitrogen, methane) can lead to very effective nitrification and carburization via complicated laser-surface-gas-plasma-interactions. This laser nitriding and laser carburizing and their basic underlying phenomena will be presented and partly explained by results of example materials (iron, titanium, aluminum, silicon) where nitride and carbide coatings can be formed by fast and easily by Excimer Laser, Nd:YAG laser, Free Electron Laser and also by femtosecond Ti:sapphire laser. This implies laser pulse durations from the nanosecond to the femtosecond regime and wavelengths from ultra-violet to infrared. The resulting surfaces, thin films, coatings and their properties are investigated by combining Mossbauer Spectroscopy, x-ray diffraction, x-ray absorption spectroscopy, Nanoindentation, Resonant Nuclear Reaction Analysis, and Rutherford Backscattering Spectroscopy.

  7. Laser therapy (image)

    MedlinePlus

    A laser is used for many medical purposes. Because the laser beam is so small and precise, it enables ... without injuring surrounding tissue. Some uses of the laser are retinal surgery, excision of lesions, and cauterization ...

  8. Lasers in Medicine.

    ERIC Educational Resources Information Center

    Hill, P. D.

    1989-01-01

    Described are the characteristics of the laser and its effects on the body. Discussed are examples of laser treatments, including angioplasty, ophthalmology, and dermatology. A discussion of lasers of clinical interest and their applications is presented. (YP)

  9. Laser-Driven Fusion.

    ERIC Educational Resources Information Center

    Gibson, A. F.

    1980-01-01

    Discusses the present status and future prospects of laser-driven fusion. Current research (which is classified under three main headings: laser-matter interaction processes, compression, and laser development) is also presented. (HM)

  10. Diode Laser Arrays

    NASA Astrophysics Data System (ADS)

    Botez, Dan; Scifres, Don R.

    2005-11-01

    Contributors; 1. Monolithic phase-locked semiconductor laser arrays D. Botez; 2. High power coherent, semiconductor laser master oscillator power amplifiers and amplifier arrays D. F. Welch and D. G. Mehuys; 3. Microoptical components applied to incoherent and coherent laser arrays J. R. Leger; 4. Modeling of diode laser arrays G. R. Hadley; 5. Dynamics of coherent semiconductor laser arrays H. G. Winfuland and R. K. Defreez; 6. High average power semiconductor laser arrays and laser array packaging with an emphasis for pumping solid state lasers R. Solarz; 7. High power diode laser arrays and their reliability D. R. Scifres and H. H. Kung; 8. Strained layer quantum well heterostructure laser arrays J. J. Coleman; 9. Vertical cavity surface emitting laser arrays C. J. Chang-Hasnain; 10. Individually addressed arrays of diode lasers D. Carlin.

  11. Lasers in Cancer Treatment

    MedlinePlus

    ... to treat cancer: carbon dioxide (CO 2 ) lasers, argon lasers, and neodymium: yttrium -aluminum-garnet (Nd:YAG) ... can be used with endoscopes. CO 2 and argon lasers can cut the skin’s surface without going ...

  12. Laser Weapons for Naval Applications

    DTIC Science & Technology

    2012-03-27

    IPG fiber lasers , 10 kW/ fiber 7 • Output wavelength is tunable (can operate in atmospheric window) Free Electron Lasers ...Multiple kilowatts over multiple kilometers • Laser power converters can be highly efficient, > 60 % • Fiber lasers are highly compact and... lasers - Free electron lasers • Background • Laser candidates • Additional capabilities - Power beaming 3 Laser Lethality -

  13. Laser accidents: Being Prepared

    SciTech Connect

    Barat, K

    2003-01-24

    The goal of the Laser Safety Officer and any laser safety program is to prevent a laser accident from occurring, in particular an injury to a person's eyes. Most laser safety courses talk about laser accidents, causes, and types of injury. The purpose of this presentation is to present a plan for safety offices and users to follow in case of accident or injury from laser radiation.

  14. Handbook of molecular lasers

    NASA Astrophysics Data System (ADS)

    Cheo, Peter K.

    The technology and applications of molecular lasers (MLs) are examined in chapters contributed by leading experts. Topics addressed include ML emission spectra, CO2 TEA lasers, RF-discharge-excited CO2 lasers, high-energy short-pulse CO2 lasers, high-power electron-beam-controlled CO2 lasers, HF/DF chemical lasers, optically pumped FIR MLs, and transients and instabilities in FIR MLs. Extensive diagrams, drawings, graphs, photographs, and tables of numerical data are provided.

  15. New laser protective eyewear

    NASA Astrophysics Data System (ADS)

    McLear, Mark

    1996-04-01

    Laser technology has significantly impacted our everyday life. Lasers are now used to correct your vision, clear your arteries, and are used in the manufacturing of such diverse products as automobiles, cigarettes, and computers. Lasers are no longer a research tool looking for an application. They are now an integral part of manufacturing. In the case of Class IV lasers, this explosion in laser applications has exposed thousands of individuals to potential safety hazards including eye damage. Specific protective eyewear designed to attenuate the energy of the laser beam below the maximum permissible exposure is required for Class 3B and Class IV lasers according to laser safety standards.

  16. Laser satellite power systems

    SciTech Connect

    Walbridge, E.W.

    1980-01-01

    A laser satellite power system (SPS) converts solar power captured by earth-orbiting satellites into electrical power on the earth's surface, the satellite-to-ground transmission of power being effected by laser beam. The laser SPS may be an alternative to the microwave SPS. Microwaves easily penetrate clouds while laser radiation does not. Although there is this major disadvantage to a laser SPS, that system has four important advantages over the microwave alternative: (1) land requirements are much less, (2) radiation levels are low outside the laser ground stations, (3) laser beam sidelobes are not expected to interfere with electromagnetic systems, and (4) the laser system lends itself to small-scale demonstration. After describing lasers and how they work, the report discusses the five lasers that are candidates for application in a laser SPS: electric discharge lasers, direct and indirect solar pumped lasers, free electron lasers, and closed-cycle chemical lasers. The Lockheed laser SPS is examined in some detail. To determine whether a laser SPS will be worthy of future deployment, its capabilities need to be better understood and its attractiveness relative to other electric power options better assessed. First priority should be given to potential program stoppers, e.g., beam attenuation by clouds. If investigation shows these potential program stoppers to be resolvable, further research should investigate lasers that are particularly promising for SPS application.

  17. [Laser physics].

    PubMed

    Banús Gassol, J M

    2008-11-01

    The commission of this article plunged me into doubt. First I should confess that I don't find excuse to escape this part if somebody wants to minimally deepen in the knowledge of the biological effects of this energy source. Secondly, when we talk about results, we use terms made and defined by Physics. Often we have polemics about results, and what really happens is that we don't reach agreements because we refer to different terms to explain the same observation; in conclusion we cannot understand each other because we do not know the adequate terms; for example, hypoxemia as oxygen deficit, which is true in an anemic patient as well as in a low oxygen saturation rate. In consequence, a good review of these concepts seems necessary to me. The third reason is the confusion that exists in our environment, I think sometimes of interest, about properties and effects of different types of laser. Only a minimal knowledge of physics will help us to state the scientific basis for understanding. The problems, nevertheless, accumulate due to the fact that the universe to which this article is directed is formed by urologists. What Physics education should we suppose they have? Superficial? Medium? Is it a collective with a uniform knowledge, being it whatever it is? The implication is clear. The article depth will depend on the answers to these questions. Nevertheless, the aim of the authors is to give a base enough to know what the laser is and how it acts. For that, the answer I gave to my questions is that the reader should understand the article and have enough base for, at least, reading critically the articles about laser published in urological journals.

  18. The Geoscience Laser Altimeter System Laser Transmitter

    NASA Technical Reports Server (NTRS)

    Afzal, R. S.; Dallas, J. L.; Yu, A. W.; Mamakos, W. A.; Lukemire, A.; Schroeder, B.; Malak, A.

    2000-01-01

    The Geoscience Laser Altimeter System (GLAS), scheduled to launch in 2001, is a laser altimeter and lidar for tile Earth Observing System's (EOS) ICESat mission. The laser transmitter requirements, design and qualification test results for this space- based remote sensing instrument are presented.

  19. Studies on lasers and laser devices

    NASA Technical Reports Server (NTRS)

    Harris, S. E.; Siegman, A. E.; Young, J. F.

    1983-01-01

    The goal of this grant was to study lasers, laser devices, and uses of lasers for investigating physical phenomena are studied. The active projects included the development of a tunable, narrowband XUV light source and its application to the spectroscopy of core excited atomic states, and the development of a technique for picosecond time resolution spectroscopy of fast photophysical processes.

  20. Laser Spectroscopy

    NASA Astrophysics Data System (ADS)

    Katori, H.; Yoneda, H.; Nakagawa, K.; Shimizu, F.

    2010-02-01

    .] -- Ultracold Ytterbium atoms in optical lattices / S. Sugawa ... [et al.] -- Ultracold polar molecules in the rovibrational ground state / J. Deiglmayr ... [et al.] -- Polar molecules near quantum degeneracy / J. Ye and D. S. Jin -- Production of a quantum gas of rovibronic ground-state molecules in an optical lattice / J. G. Danzl ... [et al.] -- Recent progress in x-ray nonlinear optics / K. Tamasaku, K. Sawada, and T. Ishikawa -- Gas in scattering media absorption spectroscopy - laser spectroscopy in unconventional environments / S. Svanberg -- Laser spectroscopy on relativistic ion beams / S. Reinhardt ... [et al.] -- Single frequency microcavity lasers and applications / L. Xu ... [et al.].

  1. Reverse laser drilling

    NASA Technical Reports Server (NTRS)

    Anthony, Thomas R. (Inventor)

    1984-01-01

    This invention provides a method for laser drilling small diameter, closely-spaced, and accurately located holes in a body of material which is transparent or substantially transparent to the laser radiation employed whereby the holes are drilled through the thickness of the body from the surface opposite to that on which the laser beam impinges to the surface of laser beam impingement.

  2. Laser photobiology and photomedicine

    SciTech Connect

    Martellucci, S.; Chester, A.N.

    1985-01-01

    This book presents information on the following topics: the physical and biological basis of photobiology and photomedicine; the biological effects and applications of laser technology; photochemotherapy; photobiology and dermatology; surgical and ophthalmological applications of lasers; laser safety; and diagnostics and technological aspects of recent laser developments.

  3. Narrow gap laser welding

    DOEpatents

    Milewski, J.O.; Sklar, E.

    1998-06-02

    A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables. 34 figs.

  4. Narrow gap laser welding

    DOEpatents

    Milewski, John O.; Sklar, Edward

    1998-01-01

    A laser welding process including: (a) using optical ray tracing to make a model of a laser beam and the geometry of a joint to be welded; (b) adjusting variables in the model to choose variables for use in making a laser weld; and (c) laser welding the joint to be welded using the chosen variables.

  5. Obstacles to Laser Safety

    SciTech Connect

    Barat, K

    2005-04-25

    The growth of laser development & technology has been remarkable. Unfortunately, a number of traps or obstacles to laser safety have also developed with that growth. The goal of this article is to highlight those traps, in the hope that an aware laser user will avoid them. These traps have been the cause or contributing factor of many a preventable laser accident.

  6. Short wavelength laser

    DOEpatents

    Hagelstein, P.L.

    1984-06-25

    A short wavelength laser is provided that is driven by conventional-laser pulses. A multiplicity of panels, mounted on substrates, are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path. When the panels are illuminated by the conventional-laser pulses, single pass EUV or soft x-ray laser pulses are produced.

  7. Longitudinal discharge laser baffles

    DOEpatents

    Warner, B.E.; Ault, E.R.

    1994-06-07

    The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam. 1 fig.

  8. Longitudinal discharge laser baffles

    DOEpatents

    Warner, Bruce E.; Ault, Earl R.

    1994-01-01

    The IR baffles placed between the window and the electrode of a longitudinal discharge laser improve laser performance by intercepting off-axis IR radiation from the laser and in doing so reduce window heating and subsequent optical distortion of the laser beam.

  9. Solar driven lasers for power satellite applications

    NASA Technical Reports Server (NTRS)

    Taussio, R.; Cassady, P.; Klosterman, E.

    1980-01-01

    The technological feasibility of using multimagawatt lasers for space power transmission is discussed. Candidate lasers include electric discharge lasers, direct optically pumped lasers, and free electron lasers.

  10. What is a Laser?

    NASA Astrophysics Data System (ADS)

    Julien, Lucile; Schwob, Catherine

    2015-10-01

    The first laser was built more than 50 years ago, inMay 1960: it was a pulsed ruby laser. It was a simple laboratory curiosity and nobody knew what its usefulness could be. Other devices were rapidly demonstrated, and the variety and number of lasers in the world increased at a huge rate. Currently, the annual laser world market is worth about 6 billion dollars. Thanks to the remarkable properties of laser light, laser applications increase steadily in the domains of industry, building, medicine, telecommunications, etc. One can find many lasers in research laboratories, and they are used more and more in our everyday life and almost everybody has already seen a laser beam. The goal of the first chapter of this book is to explain simply what a laser is, how it is built and how it operates. Firstly, let us point out the outstanding properties of the laser light.

  11. Tunable lasers- an overview

    SciTech Connect

    Guenther, B.D.; Buser, R.G.

    1982-08-01

    This overview of tunable lasers describes their applicability to spectroscopy in the ultraviolet and middle infrared ranges; to rapid on-line diagnostics by ultrashort cavity lasers; to exploration, by the free electron laser, for its wide tuning in the far infrared to submillimeter region; to remote detection, in areas such as portable pollution monitors, on-line chemical analyzers, auto exhaust analyzers, and production line controls; to photochemistry; and to other potential areas in diagnostics, communications, and medical and biological sciences. The following lasers are characterized by their tunability: solid state lasers, primarily alexandrite, with a tuning range of ca 1000 Angstroms; color center lasers; semiconductor lasers; dye lasers; gas lasers, where high-pressure CO/sub 2/ discharges are the best known example for a wide tunability range, and research is continuing in systems such as the alkali dimers; and, at wavelengths beyond 10 micrometers, the possibilities beyond Cerenkov and free electron lasers.

  12. Lasers in flow cytometry.

    PubMed

    Telford, William G

    2011-01-01

    Laser technology has advanced tremendously since the first gas lasers were incorporated into early flow cytometers. Gas lasers have been largely replaced by solid-state laser technology, making virtually any desirable visible light wavelength available for flow cytometry. Multiwavelength, white light, and wavelength tunable lasers are poised to enhance our analytical capabilities even further. In this chapter, I summarize the role that lasers play in cytometry, and the practical characteristics that make a laser appropriate for flow cytometry. I then review the latest single wavelength lasers available for flow cytometry, and how they can be used to excite the ever-expanding array of available fluorochromes. Finally, I review the contribution and potential of the latest tunable laser technology to flow cytometry, and show several examples of these novel sources integrated into production instruments. Technical details and critical parameters for successful application of these lasers for biomedical analysis are covered in depth.

  13. Surgical lasers in dermatology

    NASA Astrophysics Data System (ADS)

    Szymanczyk, Jacek; Nowakowski, Wlodzimierz; Golebiowska, Aleksandra; Michalska, I.; Mindak, Marek K.

    1997-10-01

    Almost every laser for medical applications was first tried in dermatology. The efficiency of YAG, CO2, and Argon lasers on this area and their potential advantages over conventional methods were mostly evaluated by cosmetic effect of laser therapy. The indications for different laser treatment in such dermatological cases as: angiomas, telangiectasias, pigmented lesions, nevus flammeus congenitus, deep cavernous angiomas, skin neoplasms and condylomata acuminata are discussed in this paper and the results of the laser therapy are also presented.

  14. Laser Reliability Prediction

    DTIC Science & Technology

    1975-08-01

    Lasers, Quality Level 1 - Group 2 32 5.3-3 Kolmogorov-Smirnoff Test - Helium/Neon Lasers, Quality Level 1 33 5.3-4 Welbull Analysis...institutions through- out the United States and Canada. The collected laser data were grouped, analyzed, and statistically tested for homogeneity...sources were Initially contacted by letter questionnaires In which personnel were requested to describe any laser component life test or laser system

  15. Intracavity Raman lasers

    SciTech Connect

    Band, Y.B.; Ackerhalt, J.R.; Krasinski, J.S.; Heller, D.F.

    1989-02-01

    Experimental and theoretical studies of intracavity Raman lasers are presented. Advantages of intracavity Raman lasers, particularly for low-emission cross section and broadly tunable vibronic gain media, are described. Experimental studies of a hydrogen gas Raman laser pumped inside the cavity of an alexandrite laser are presented. A theoretical model of the dynamics of a unidirectional intracavity Raman ring laser is developed and solved analytically. This model is adapted to simulate experiments.

  16. Mercury Bromide Laser Research.

    DTIC Science & Technology

    1981-05-04

    Discharge", Optics Lett., 2(3), (March 1978). 7. R. Burnham, "Discharge Pumped Mercuric Halide Dissociation Lasers", Appl. Phys. Lett., 33: 15 (July 1978...laser and fluorescence signals. Neutral density filters served to prevent saturation of the detector during the laser measurements. F. Laser Output as a...REFERENCES . E. J. Schimitschek and J. E. Celto, " Mercuric Bromide Dissociation Laser in an Electric Discharge," Optics Lett. 2(3), March 1978. This

  17. Nanocrystal waveguide (NOW) laser

    DOEpatents

    Simpson, John T.; Simpson, Marcus L.; Withrow, Stephen P.; White, Clark W.; Jaiswal, Supriya L.

    2005-02-08

    A solid state laser includes an optical waveguide and a laser cavity including at least one subwavelength mirror disposed in or on the optical waveguide. A plurality of photoluminescent nanocrystals are disposed in the laser cavity. The reflective subwavelength mirror can be a pair of subwavelength resonant gratings (SWG), a pair of photonic crystal structures (PC), or a distributed feedback structure. In the case of a pair of mirrors, a PC which is substantially transmissive at an operating wavelength of the laser can be disposed in the laser cavity between the subwavelength mirrors to improve the mode structure, coherence and overall efficiency of the laser. A method for forming a solid state laser includes the steps of providing an optical waveguide, creating a laser cavity in the optical waveguide by disposing at least one subwavelength mirror on or in the waveguide, and positioning a plurality of photoluminescent nanocrystals in the laser cavity.

  18. Infrared laser system

    DOEpatents

    Cantrell, Cyrus D.; Carbone, Robert J.; Cooper, Ralph

    1982-01-01

    An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture.

  19. Infrared laser system

    DOEpatents

    Cantrell, Cyrus D.; Carbone, Robert J.; Cooper, Ralph S.

    1977-01-01

    An infrared laser system and method for isotope separation may comprise a molecular gas laser oscillator to produce a laser beam at a first wavelength, Raman spin flip means for shifting the laser to a second wavelength, a molecular gas laser amplifier to amplify said second wavelength laser beam to high power, and optical means for directing the second wavelength, high power laser beam against a desired isotope for selective excitation thereof in a mixture with other isotopes. The optical means may include a medium which shifts the second wavelength high power laser beam to a third wavelength, high power laser beam at a wavelength coincidental with a corresponding vibrational state of said isotope and which is different from vibrational states of other isotopes in the gas mixture.

  20. Laser Surveying

    NASA Technical Reports Server (NTRS)

    1978-01-01

    NASA technology has produced a laser-aided system for surveying land boundaries in difficult terrain. It does the job more accurately than conventional methods, takes only one-third the time normally required, and is considerably less expensive. In surveying to mark property boundaries, the objective is to establish an accurate heading between two "corner" points. This is conventionally accomplished by erecting a "range pole" at one point and sighting it from the other point through an instrument called a theodolite. But how do you take a heading between two points which are not visible to each other, for instance, when tall trees, hills or other obstacles obstruct the line of sight? That was the problem confronting the U.S. Department of Agriculture's Forest Service. The Forest Service manages 187 million acres of land in 44 states and Puerto Rico. Unfortunately, National Forest System lands are not contiguous but intermingled in complex patterns with privately-owned land. In recent years much of the private land has been undergoing development for purposes ranging from timber harvesting to vacation resorts. There is a need for precise boundary definition so that both private owners and the Forest Service can manage their properties with confidence that they are not trespassing on the other's land.

  1. Alexandrite laser pumped by semiconductor lasers

    SciTech Connect

    Scheps, R.; Gately, B.M.; Myers, J.F. ); Krasinski, J.S. ); Heller, D.F. )

    1990-06-04

    We report the first operation of a direct diode-pumped tunable chromium-doped solid-state laser. A small alexandrite (Cr:BeAl{sub 2}O{sub 4}) crystal was longitudinally pumped by two visible laser diodes. The threshold pump power was 12 mW using the {ital R}{sub 1} line at 680.4 nm for the pump transition, and the slope efficiency was 25%. The measured laser output bandwidth was 2.1 nm.

  2. Alexandrite laser pumped by semiconductor lasers

    NASA Astrophysics Data System (ADS)

    Scheps, Richard; Gately, Bernard M.; Myers, Joseph F.; Krasinski, Jerzy S.; Heller, Donald F.

    1990-06-01

    We report the first operation of a direct diode-pumped tunable chromium-doped solid-state laser. A small alexandrite (Cr:BeAl2O4) crystal was longitudinally pumped by two visible laser diodes. The threshold pump power was 12 mW using the R1 line at 680.4 nm for the pump transition, and the slope efficiency was 25%. The measured laser output bandwidth was 2.1 nm.

  3. Lasers in aviation

    NASA Astrophysics Data System (ADS)

    Goncharov, I. N.; Dezhin, V. N.; Kutakhov, V. P.; Petukhov, A. V.; Sidorin, V. M.; Sukhar, I. M.

    The way in which lasers are being incorporated into the military aircraft of the United States and the countries of Western Europe is discussed. Descriptions are given of laser weapons-guiding systems (including ranger finders and systems for target illumination), laser systems for navigation and flight-safety assurance (gyroscopes, velocity gauges, altimeters, systems providing meteorological data, proximity warning systems), and laser systems for air reconnaissance, communications, and control. Attention is also given to the Glissada laser guide path system, developed in the USSR. The physics of the systems is emphasized in the description and the principles underlying the operation of a laser are discussed in the introduction.

  4. Lasers in periodontics.

    PubMed

    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie

    2012-08-01

    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20(th) century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics.

  5. Tunable chromium lasers

    SciTech Connect

    Chase, L.L.; Payne, S.A.

    1989-01-01

    During the decade that has passed since the discovery of the alexandrite laser, many other tunable vibronic sideband lasers based on Cr/sup 3 +/ have been developed. These lasers span the wavelength range from 700 nm to at least 1235 nm. Experimental and theoretical research has provided an understanding of the important factors that influence the performance of these Cr/sup 3 +/ lasers and other solid state vibronic lasers. The intrinsic performance levels of some of the most promising Cr/sup 3 +/ lasers are evaluated from extrapolated slope efficiency measurements. 7 refs., 4 figs., 2 tabs.

  6. Maser and laser engineering

    SciTech Connect

    Ishii, T.K.

    1980-01-01

    This book is intended to be a textbook for an upper division one-semester electrical engineering course. Students are expected to have had some undegraduate course work in modern physics and in electromagnetic field theory. General aspects regarding devices based on quantum electronics are considered along with gas masers, solid masers, gas lasers, solid lasers, semiconductor lasers, liquid lasers, modulation techniques for lasers, and opto-electrical demodulators and energy convertors. Attention is given to quantum electric harmonic generators, Raman lasers, optical parametric interactions, holograms, optical terms, crystallographic terms, band theory, Schroedinger formulation and Dirac formation, and the quantum number of electrons in a hydrogen atom.

  7. Laser peening of metals- enabling laser technology

    SciTech Connect

    Dane, C.B.; Hackel, L.A.; Daly, J.; Harrisson, J.

    1997-11-13

    Laser peening, a surface treatment for metals, employs laser induced shocks to create deep and intense residual stresses in critical components. In many applications this technology is proving to be superior to conventional treatments such as shot peening. The laser peening process has generated sufficiently impressive results to move it from a laboratory demonstration phase into a significant industrial process. However until now this evolution has been slowed because a laser system meeting the average power requirements for a high throughput process has been lacking.

  8. Laser Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hollberg, Leo; Bergquist, James Charles; Kasevich, Mark A.

    2008-04-01

    Degenerate gases. Probing vortex pair sizes in the Berezinskii-Kosterlitz-Thouless regime on a two-dimensional lattice of Bose-Einstein condensates / V. Schweikhard ... [et al.]. Interacting Bose-Einstein condensates in random potentials / P. Bouyer ... [et al.]. Towards quantum magnetism with ultracold atoms in optical lattices / I. Bloch -- Precision measurement and fundamental physics. T-violation and the search for a permanent electric dipole moment of the mercury atom / E. N. Fortson -- Quantum information and control I. Quantum information processing and ramsey spectroscopy with trapped ions / C. F. Roos ... [et al.]. Quantum non-demolition counting of photons in a cavity / S. Haroche ... [et al.] -- Ultra-fast control and spectroscopy. Frequency-Comb- assisted mid-infrared spectroscopy / P. de Natale ... [et al.] -- Precision measurement and applications. Precision gravity tests by atom interferometry / G. M. Tino ... [et al.] -- Novel spectroscopic applications. On a variation of the proton-electron mass ratio / W. Ubachs ... [et al.] -- Quantum information and control II. Quantum interface between light and atomic ensembles / H. Krauter ... [et al.] -- Degenerate Fermi gases. An atomic Fermi gas near a P-wave Feshbach resonance / D. S. Jin, J. P. Gaebler and J. T. Stewart. Bragg scattering of correlated atoms from a degenerate Fermi gas / R. J. Ballagh, K. J. Challis and C. W. Gardiner -- Spectroscopy and control of atoms and molecules. Stark and Zeeman deceleration of neutral atoms and molecules / S. D. Hogan ... [et al.]. Generation of coherent, broadband and tunable soft x-ray continuum at the leading edge of the driver laser pulse / A. Jullien ... [et al.]. Controlling neural atoms and photons with optical conveyor belts and ultrathin optical fibers / D. Meschede. W. Alt and A. Rauschenbeutel -- Spectroscopy on the small scale. Wide-field cars-microscopy / C. Heinrich ... [et al.]. Atom nano-optics and nano-lithography / V. I. Balykin ... [et al

  9. Laser amplifier and method

    DOEpatents

    Backus, Sterling; Kapteyn, Henry C.; Murnane, Margaret M.

    1997-01-01

    Laser amplifiers and methods for amplifying a laser beam are disclosed. A representative embodiment of the amplifier comprises first and second curved mirrors, a gain medium, a third mirror, and a mask. The gain medium is situated between the first and second curved mirrors at the focal point of each curved mirror. The first curved mirror directs and focuses a laser beam to pass through the gain medium to the second curved mirror which reflects and recollimates the laser beam. The gain medium amplifies and shapes the laser beam as the laser beam passes therethough. The third mirror reflects the laser beam, reflected from the second curved mirror, so that the laser beam bypasses the gain medium and return to the first curved mirror, thereby completing a cycle of a ring traversed by the laser beam. The mask defines at least one beam-clipping aperture through which the laser beam passes during a cycle. The gain medium is pumped, preferably using a suitable pumping laser. The laser amplifier can be used to increase the energy of continuous-wave or, especially, pulsed laser beams including pulses of femtosecond duration and relatively high pulse rate.

  10. Laser amplifier and method

    DOEpatents

    Backus, S.; Kapteyn, H.C.; Murnane, M.M.

    1997-07-01

    Laser amplifiers and methods for amplifying a laser beam are disclosed. A representative embodiment of the amplifier comprises first and second curved mirrors, a gain medium, a third mirror, and a mask. The gain medium is situated between the first and second curved mirrors at the focal point of each curved mirror. The first curved mirror directs and focuses a laser beam to pass through the gain medium to the second curved mirror which reflects and recollimates the laser beam. The gain medium amplifies and shapes the laser beam as the laser beam passes therethrough. The third mirror reflects the laser beam, reflected from the second curved mirror, so that the laser beam bypasses the gain medium and return to the first curved mirror, thereby completing a cycle of a ring traversed by the laser beam. The mask defines at least one beam-clipping aperture through which the laser beam passes during a cycle. The gain medium is pumped, preferably using a suitable pumping laser. The laser amplifier can be used to increase the energy of continuous-wave or, especially, pulsed laser beams including pulses of femtosecond duration and relatively high pulse rate. 7 figs.

  11. Phased laser array for generating a powerful laser beam

    DOEpatents

    Holzrichter, John F.; Ruggiero, Anthony J.

    2004-02-17

    A first injection laser signal and a first part of a reference laser beam are injected into a first laser element. At least one additional injection laser signal and at least one additional part of a reference laser beam are injected into at least one additional laser element. The first part of a reference laser beam and the at least one additional part of a reference laser beam are amplified and phase conjugated producing a first amplified output laser beam emanating from the first laser element and an additional amplified output laser beam emanating from the at least one additional laser element. The first amplified output laser beam and the additional amplified output laser beam are combined into a powerful laser beam.

  12. Fiber-delivered mid-infrared (6-7) laser ablation of retinal tissue under perfluorodecalin

    NASA Astrophysics Data System (ADS)

    Mackanos, Mark A.; Joos, Karen M.; Jansen, E. Duco

    2003-07-01

    The Er:YAG laser (l=2.94mm) is an effective tool in vitreo-retinal surgery. Pulsed mid-infrared (l=6.45 mm) radiation from the Free Electron Laser has been touted as a potentially superior cutting tool. To date, use of this laser has been limited to applications in an air environment. The goal of this study was: 1) determine feasibility of fiberoptic delivery of 6.45mm using silverhalide fibers (d=700mm); 2) use infrared transparent vitreous substitute (perfluorodecalin) to allow non-contact ablation of the retina at 6.45mm. Fiber damage threshold=7.8J/cm2 (0.54GW/cm2) while transmission loss=0.54dB/m, allowing supra-ablative radiant exposures to the target. FTIR measurements of perfluorodecalin at 6.45mm yielded ma=3mm-1. Pump-probe imaging of ablation of a tissue-phantom through perfluorodecalin showed feasibility of non-contact ablation at l=6.45mm. Ablation of the retinal membranes of enucleated pig eyes was carried out under perfluorodecalin (5 Hz, 1.3 J/cm2). Each eye was cut along its equator to expose the retina. Vitreous was replaced by perfluorodecalin and laser radiation was delivered to the retina via the silverhalide fiber. The eye was rotated (at 2 rpm) using a stepper motor (0.9o/step) to create an ablation circle around the central axis of the retina (50% spot-to-spot overlap). Histological analysis of ablation yield and collateral damage will be presented. We have shown that using l=6.45mm delivered via silver halide fibers through perfluorodecalin allowed non-contact laser ablation. Remote structures are shielded, as the radiant exposure falls below the ablation threshold owing non-negligible absorption of perfluorodecalin at 6.45mm. This may optimize efficacy and safety of laser-based vitreoretinal surgery.

  13. Laser particle sorter

    DOEpatents

    Martin, J.C.; Buican, T.N.

    1987-11-30

    Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

  14. Laser particle sorter

    DOEpatents

    Martin, John C.; Buican, Tudor N.

    1989-01-01

    Method and apparatus for sorting particles, such as biological particles. A first laser defines an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam interrogates the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam intersects the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis.

  15. Slender tip laser scalpel

    DOEpatents

    Veligdan, James T.

    2004-01-06

    A laser scalpel includes a ribbon optical waveguide extending therethrough and terminating at a slender optical cutting tip. A laser beam is emitted along the height of the cutting tip for cutting tissue therealong.

  16. Laser device and method

    SciTech Connect

    Myers, J. D.

    1985-06-25

    A simplified, relatively inexpensive laser device, wherein the laser elements are fixed in a body exoskeleton of electrical insulating material having a low coefficient of thermal expansion. The preferred embodiment includes a shotgun type laser filter having parallel bores which receive the laser flashlamp and laser rod in fixed relation in a body chamber. The reflector surrounds the laser filter and retains the filter within the body chamber. In the preferred method of this invention, several controlled lasing pulses are generated with each illumination pulse of the flashlamp, substantially increasing the efficiency of the laser device. The number of pulses is generally controlled by increasing the voltage to the flashlamp. The rapid multiple lasing pulses generate an elongated plasma in a fluid medium, such as the vitreous fluid body of an eye which makes the laser device extemely efficient for treating glaucoma and other medical treatments.

  17. Laser hair removal.

    PubMed

    Wanner, Molly

    2005-01-01

    Since 1996, there have been numerous advances in hair laser removal that utilize melanin as a chromophore. All of the devices on the market may be used in patients with light skin (phototypes I-III) and yield hair reduction near 75%. The ruby (694 nm) laser, alexandrite (755 nm) laser, and diode (810 nm) laser, as well as intense pulsed light are commonly used devices for hair laser removal. The long-pulsed Nd:YAG (1064 nm) laser represents the safest device for hair removal in dark-skinned patients because of its long wavelength, although the diode laser, alexandrite laser, and intense pulse light may be used. For treatment of light hair, combination radiofrequency and optical devices as well as photodynamic therapy are under investigation.

  18. Laser Radar Animation

    NASA Video Gallery

    Laser and radar instruments aboard NASA aircraft provide measurements of the snow and ice surface and down to the bedrock under the ice. Lasers, with a shorter wavelength, measure the surface eleva...

  19. Direct nuclear pumped laser

    DOEpatents

    Miley, George H.; Wells, William E.; DeYoung, Russell J.

    1978-01-01

    There is provided a direct nuclear pumped gas laser in which the lasing mechanism is collisional radiated recombination of ions. The gas laser active medium is a mixture of the gases, with one example being neon and nitrogen.

  20. Laser surgery - skin

    MedlinePlus

    Surgery using a laser ... used is directly related to the type of surgery being performed and the color of the tissue ... Laser surgery can be used to: Close small blood vessels to reduce blood loss Remove warts , moles , sunspots, and ...

  1. Laser programs highlights 1993

    SciTech Connect

    1995-06-01

    Over the last two decades, the scope of our laser research has grown immensely. The small, low-power laser systems of our early days have given way to laser systems of record-breaking size and power. Now we are focusing our activities within the target physics and laser science programs to support the ignition and gain goals of the proposed glass-laser National Ignition Facility. In our laser isotope separation work, we completed the most important set of experiments in the history of the AVLIS Program in 1993, which culminated in a spectacularly successful run that met or exceeded all our objectives. We are also developing lasers and laser-related technologies for a variety of energy, commercial, and defense uses. On the horizon are transfers of important technologies for waste treatment, x-ray lithography, communications and security, optical imaging, and remote sensing, among others.

  2. MESSENGER Laser Altimeter

    NASA Video Gallery

    MESSENGER's Mercury Laser Altimeter sends out laser pulses that hit the ground and return to the instrument. The amount of light that returns for each pulse gives the reflectance at that point on t...

  3. Carbon dioxide slab laser

    SciTech Connect

    Tulip, J.

    1988-01-12

    A gas slab laser is described comprising: first and second elongated electrodes each including a planar light reflecting surface disposed so as to form a light guide only in a plane perpendicular to the planar surface and to define a gas discharge gap therebetween; a laser gas disposed in the gap; and means for applying a radio frequency current between the first and second electrodes to establish a laser-exciting discharge in the laser gas.

  4. CO2 laser modeling

    NASA Technical Reports Server (NTRS)

    Johnson, Barry

    1992-01-01

    The topics covered include the following: (1) CO2 laser kinetics modeling; (2) gas lifetimes in pulsed CO2 lasers; (3) frequency chirp and laser pulse spectral analysis; (4) LAWS A' Design Study; and (5) discharge circuit components for LAWS. The appendices include LAWS Memos, computer modeling of pulsed CO2 lasers for lidar applications, discharge circuit considerations for pulsed CO2 lidars, and presentation made at the Code RC Review.

  5. Alkali-vapor lasers

    NASA Astrophysics Data System (ADS)

    Zweiback, J.; Komashko, A.; Krupke, W. F.

    2010-02-01

    We report on the results from several of our alkali laser systems. We show highly efficient performance from an alexandrite-pumped rubidium laser. Using a laser diode stack as a pump source, we demonstrate up to 145 W of average power from a CW system. We present a design for a transversely pumped demonstration system that will show all of the required laser physics for a high power system.

  6. Laser shaping of cartilage

    NASA Astrophysics Data System (ADS)

    Sobol, Emil N.; Bagratashvili, Victor N.; Omelchenko, Alexander I.; Sviridov, Alexander P.; Helidonis, Emmanuel S.; Kavvalos, George; Christodoulou, P. N.; Naoumidi, I.; Velegrakis, G.; Ovchinnikov, Yuriy M.; Shechter, A.

    1994-09-01

    The carbon dioxide laser has been used for the first time to change the cartilage's shape. After the laser irradiation the cartilage has the tendency to retain its new form. Different types of laser modified cartilage structures were studied. The inferred physical mechanism for cartilage shaping using the stresses relaxation process is presented. The clinical significance of the results for corrective laser surgery is discussed.

  7. Tunable semiconductor lasers

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

    2006-01-01

    Tunable semiconductor lasers are disclosed requiring minimized coupling regions. Multiple laser embodiments employ ring resonators or ring resonator pairs using only a single coupling region with the gain medium are detailed. Tuning can be performed by changing the phase of the coupling coefficient between the gain medium and a ring resonator of the laser. Another embodiment provides a tunable laser including two Mach-Zehnder interferometers in series and a reflector coupled to a gain medium.

  8. Short wavelength laser

    DOEpatents

    Hagelstein, Peter L.

    1986-01-01

    A short wavelength laser (28) is provided that is driven by conventional-laser pulses (30, 31). A multiplicity of panels (32), mounted on substrates (34), are supported in two separated and alternately staggered facing and parallel arrays disposed along an approximately linear path (42). When the panels (32) are illuminated by the conventional-laser pulses (30, 31), single pass EUV or soft x-ray laser pulses (44, 46) are produced.

  9. Laser cutting system

    SciTech Connect

    Dougherty, Thomas J

    2015-03-03

    A workpiece cutting apparatus includes a laser source, a first suction system, and a first finger configured to guide a workpiece as it moves past the laser source. The first finger includes a first end provided adjacent a point where a laser from the laser source cuts the workpiece, and the first end of the first finger includes an aperture in fluid communication with the first suction system.

  10. Laser Assisted Microsurgical Anastomosis.

    DTIC Science & Technology

    1983-09-22

    Miami School of Medicine This Paper describes new experimental microsurgical procedures that * utilize laser infrared energy emitted at 10.6 um to...dioxide laser microsurgical technique takes advantage of the very high absorption of laser energy (at 10.6 um) by water in soft tissue to effect successful...describes a new surgical technique that utilizes laser heat energy to repair transected rat sciatic nerves, and nerve grafts. The energy emitted at

  11. Laser Detection of Pollution.

    ERIC Educational Resources Information Center

    Patel, C. K. N.

    1978-01-01

    Discusses the use of laser spectroscopy in determining the presence of specific gaseous constituents. Three of currently used modes for laser detection of pollution are reviewed; (1) long-path measurements; (2) laser raman (differential absorption) measurements; and (3) optoacoustic detection. (HM)

  12. Laser bottom hole assembly

    SciTech Connect

    Underwood, Lance D; Norton, Ryan J; McKay, Ryan P; Mesnard, David R; Fraze, Jason D; Zediker, Mark S; Faircloth, Brian O

    2014-01-14

    There is provided for laser bottom hole assembly for providing a high power laser beam having greater than 5 kW of power for a laser mechanical drilling process to advance a borehole. This assembly utilizes a reverse Moineau motor type power section and provides a self-regulating system that addresses fluid flows relating to motive force, cooling and removal of cuttings.

  13. Velocimetry with diode lasers

    NASA Astrophysics Data System (ADS)

    de Mul, F. F. M.; Jentink, H. W.; Koelink, M.; Greve, J.; Aarnoudse, J. G.

    The history of the application of diode lasers in velocimetry is reviewed. Some problems arising when using those lasers, e.g., mode hopping and wavelength shifts caused by temperature effects, are discussed, together with coherence effects encountered with diode lasers. The application in dual-beam velocimetry, in direct-contact velocimetry and in velocimetry using self-mixing will be discussed.

  14. Argon laser for otosclerosis

    NASA Astrophysics Data System (ADS)

    Michalski, Wojciech; Pospiech, Lucyna; Jankowska-Kuc, Malgorzata

    1995-03-01

    Up to now, among different kinds of lasers an argon laser is mostly used for otosclerosis. Exposure conditions at use of the laser beam are still not well defined. In order to achieve the optimum conditions a series of experiments has been made. Obtained results are presented in this paper.

  15. Laser power transmission

    NASA Technical Reports Server (NTRS)

    Conway, Edmund J.

    1992-01-01

    An overview of previous studies related to laser power transmission is presented. Particular attention is given to the use of solar pumped lasers for space power applications. Three general laser mechanisms are addressed: photodissociation lasing driven by sunlight, photoexcitation lasing driven directly by sunlight, and photoexcitation lasing driven by thermal radiation.

  16. LaserFest Celebration

    SciTech Connect

    Dr. Alan Chodos; Elizabeth A. Rogan

    2011-08-25

    LaserFest was the yearlong celebration, during 2010, of the 50th anniversary of the demonstration of the first working laser. The goals of LaserFest were: to highlight the impact of the laser in its manifold commercial, industrial and medical applications, and as a tool for ongoing scientific research; to use the laser as one example that illustrates, more generally, the route from scientific innovation to technological application; to use the laser as a vehicle for outreach, to stimulate interest among students and the public in aspects of physical science; to recognize and honor the pioneers who developed the laser and its many applications; to increase awareness among policymakers of the importance of R&D funding as evidenced by such technology as lasers. One way in which LaserFest sought to meet its goals was to encourage relevant activities at a local level all across the country -- and also abroad -- that would be identified with the larger purposes of the celebration and would carry the LaserFest name. Organizers were encouraged to record and advertise these events through a continually updated web-based calendar. Four projects were explicitly detailed in the proposals: 1) LaserFest on the Road; 2) Videos; 3) Educational material; and 4) Laser Days.

  17. Laser Fundamentals and Experiments.

    ERIC Educational Resources Information Center

    Van Pelt, W. F.; And Others

    As a result of work performed at the Southwestern Radiological Health Laboratory with respect to lasers, this manual was prepared in response to the increasing use of lasers in high schools and colleges. It is directed primarily toward the high school instructor who may use the text for a short course in laser fundamentals. The definition of the…

  18. Infrared diode laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Civiš, S.; Cihelka, J.; Matulková, I.

    2010-12-01

    Three types of lasers (double-heterostructure 66 K InAsSb/InAsSbP laser diode, room temperature, multi quantum wells with distributed feedback (MQW with DFB) (GaInAsSb/AlGaAsSb based) diode laser and vertical cavity surface emitting lasers (VCSELs) (GaSb based) have been characterized using Fourier transform emission spectroscopy and compared. The photoacoustic technique was employed to determine the detection limit of formaldehyde (less than 1 ppmV) for the strongest absorption line of the v3 + v5 band in the emission region of the GaInAsSb/AlGaAsSb diode laser. The detection limit (less than 10 ppbV) of formaldehyde was achieved in the 2820 cm-1 spectral range in case of InAsSb/InAsSbP laser (fundamental bands of v1, v5). Laser sensitive detection (laser absorption together with high resolution Fourier transform infrared technique including direct laser linewidth measurement, infrared photoacoustic detection of neutral molecules (methane, form-aldehyde) is discussed. Additionally, very sensitive laser absorption techniques of such velocity modulation are discussed for case of laser application in laboratory research of molecular ions. Such sensitive techniques (originally developed for lasers) contributed very much in identifying laboratory microwave spectra of a series of anions (C6H-, C4H-, C2H-, CN-) and their discovery in the interstellar space (C6H-, C4H-).

  19. Laser Programs Highlights 1998

    SciTech Connect

    Lowdermilk, H.; Cassady, C.

    1999-12-01

    This report covers the following topics: Commentary; Laser Programs; Inertial Confinement Fusion/National Ignition Facility (ICF/NIF); Atomic Vapor Laser Isotope Separation (AVLIS); Laser Science and Technology (LS&T); Information Science and Technology Program (IS&T); Strategic Materials Applications Program (SMAP); Medical Technology Program (MTP) and Awards.

  20. Lasers for nonlinear microscopy.

    PubMed

    Wise, Frank

    2013-03-01

    Various versions of nonlinear microscopy are revolutionizing the life sciences, almost all of which are made possible because of the development of ultrafast lasers. In this article, the main properties and technical features of short-pulse lasers used in nonlinear microscopy are summarized. Recent research results on fiber lasers that will impact future instruments are also discussed.

  1. Polarization feedback laser stabilization

    DOEpatents

    Esherick, Peter; Owyoung, Adelbert

    1988-01-01

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other.

  2. Zeeman laser gyroscopes

    SciTech Connect

    Azarova, V V; Golyaev, Yu D; Saveliev, I I

    2015-02-28

    The history of invention and development of Zeeman laser gyroscopes, specific features of their optical scheme and operation principle are described. The construction and element base of modern laser angular velocity sensors with Zeeman-based frequency biasing are considered. The problems and prospects of their development are discussed. (laser gyroscopes)

  3. Excimer Lasers In Medicine

    NASA Astrophysics Data System (ADS)

    Tittel, Frank K.; Saidi, Iyad S.; Pettit, George H.; Wisoff, P. J.; Sauerbrey, Roland A.

    1989-06-01

    Excimer lasers emit light energy, short optical pulses at ultraviolet wavelengths, that results in a unique laser tissue interaction. This has led to an increasing number of studies into medical applications of these lasers in fields such as ophthalmology, urology, cardiology and neurology.

  4. Solar pumped laser

    NASA Technical Reports Server (NTRS)

    Lee, J. H.; Hohl, F.; Weaver, W. R. (Inventor)

    1984-01-01

    A solar pumped laser is described in which the lasant is a gas that will photodissociate and lase when subjected to sunrays. Sunrays are collected and directed onto the gas lasant to cause it to lase. Applications to laser propulsion and laser power transmission are discussed.

  5. Laser material processing system

    DOEpatents

    Dantus, Marcos

    2015-04-28

    A laser material processing system and method are provided. A further aspect of the present invention employs a laser for micromachining. In another aspect of the present invention, the system uses a hollow waveguide. In another aspect of the present invention, a laser beam pulse is given broad bandwidth for workpiece modification.

  6. Diode laser and endoscopic laser surgery.

    PubMed

    Sullins, Kenneth E

    2002-05-01

    Two functionally important differences exist between the diode laser and the carbon dioxide (CO2) laser (used more commonly in small animal surgery). Diode laser energy is delivered through a quartz fiber instead of being reflected through an articulated arm or waveguide. Quartz fibers are generally more flexible and resilient than waveguides and can be inserted through an endoscope for minimally invasive procedures. Laser-tissue interaction is the other significant difference. The CO2 laser is completely absorbed by water, which limits the effect to visible tissue. The diode wavelength is minimally absorbed by water and may affect tissue as deep as 10 mm below the surface in the free-beam mode. With proper respect for the tissue effect, these differences can be used to the advantage of the patient.

  7. Er:YAG laser ablation of epiretinal membranes in perfluorocarbon fluid-filled eyeballs: a preliminary report

    NASA Astrophysics Data System (ADS)

    Frenz, Martin; Ith, Michael; Weber, Heinz P.; Wesendahl, Th.; Janknecht, P.

    1998-06-01

    Purpose: The Er:YAG laser emitting radiation at a wavelength of 2.94 micrometer has been shown to produce precise tissue ablation because of the high water absorption at this wavelength. These studies evaluated the effects of the Er:YAG laser on pig retina utilizing a perfluoro-carbon/retina interphase with the goal to precisely ablate epiretinal membranes. Method: Various laser pulse energies were applied to the surface of pig retinas in perfluorocarbon filled enucleated eyes using a specially designed rotating sample holder. Free running ((tau) equals 250 microseconds) Er:YAG laser pulses were transmitted through a zirconium fluoride (ZrF4) fiber guarded by a low OH-quartz fiber at its distal tip. The tip diameters measured 400 micrometers and 1 mm. The fiber probe was elevated 1 mm above the retinal surface. The laser energy was applied in a systematic fashion while alternating energy settings and probe diameters. Radiant exposures were set to 1 J/cm2, 3 J/cm2, 5 J/cm2, and 10 J/cm2. Results: Eight of ten eyes were treated with concentric circles of 3.5 mm, 6.5 mm, and 9.5 mm radius. The remaining two eyes were treated with a hand held probe. Tissue ablation increased with radiant exposure in a linear fashion. At a radiant exposure of 1 J/cm2, tissue ablation was minimal with a maximum tissue ablation depth of 10 micrometers and minimal thermal damage to adjacent tissue. A radiant exposure of 10 J/cm2 produced an ablation depth of 30 - 50 micrometers. As the ablation was performed under perfluorcarbon fluid, used as transmitting medium, no laser- induced pressure transients have been measured. Conclusion: The Er:YAG laser in combination with perfluorocarbon fluid produced precise and homogeneous tissue ablation of the pig retina. Such precise tissue ablation needs to be achieved in order to safely ablate epiretinal membranes in close proximity to the retina surface. Further in-vivo experiments will be done to examine the functionality of the retina after laser

  8. Chalcogenide glass microsphere laser.

    PubMed

    Elliott, Gregor R; Murugan, G Senthil; Wilkinson, James S; Zervas, Michalis N; Hewak, Daniel W

    2010-12-06

    Laser action has been demonstrated in chalcogenide glass microsphere. A sub millimeter neodymium-doped gallium lanthanum sulphide glass sphere was pumped at 808 nm with a laser diode and single and multimode laser action demonstrated at wavelengths between 1075 and 1086 nm. The gallium lanthanum sulphide family of glass offer higher thermal stability compared to other chalcogenide glasses, and this, along with an optimized Q-factor for the microcavity allowed laser action to be achieved. When varying the pump power, changes in the output spectrum suggest nonlinear and/or thermal effects have a strong effect on laser action.

  9. Dual Wavelength Lasers

    NASA Technical Reports Server (NTRS)

    Walsh, Brian M.

    2010-01-01

    Dual wavelength lasers are discussed, covering fundamental aspects on the spectroscopy and laser dynamics of these systems. Results on Tm:Ho:Er:YAG dual wavelength laser action (Ho at 2.1 m and Er at 2.9 m) as well as Nd:YAG (1.06 and 1.3 m) are presented as examples of such dual wavelength systems. Dual wavelength lasers are not common, but there are criteria that govern their behavior. Based on experimental studies demonstrating simultaneous dual wavelength lasing, some general conclusions regarding the successful operation of multi-wavelength lasers can be made.

  10. Laser Diode Ignition (LDI)

    NASA Technical Reports Server (NTRS)

    Kass, William J.; Andrews, Larry A.; Boney, Craig M.; Chow, Weng W.; Clements, James W.; Merson, John A.; Salas, F. Jim; Williams, Randy J.; Hinkle, Lane R.

    1994-01-01

    This paper reviews the status of the Laser Diode Ignition (LDI) program at Sandia National Labs. One watt laser diodes have been characterized for use with a single explosive actuator. Extensive measurements of the effect of electrostatic discharge (ESD) pulses on the laser diode optical output have been made. Characterization of optical fiber and connectors over temperature has been done. Multiple laser diodes have been packaged to ignite multiple explosive devices and an eight element laser diode array has been recently tested by igniting eight explosive devices at predetermined 100 ms intervals.

  11. X-ray laser

    DOEpatents

    Nilsen, Joseph

    1991-01-01

    An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

  12. Laser assisted deposition

    NASA Technical Reports Server (NTRS)

    Dutta, S.

    1983-01-01

    Applications of laser-based processing techniques to solar cell metallization are discussed. Laser-assisted thermal or photolytic maskless deposition from organometallic vapors or solutions may provide a viable alternative to photovoltaic metallization systems currently in use. High power, defocused excimer lasers may be used in conjunction with masks as an alternative to direct laser writing to provide higher throughput. Repeated pulsing with excimer lasers may eliminate the need for secondary plating techniques for metal film buildup. A comparison between the thermal and photochemical deposition processes is made.

  13. Stabilized Zeeman split laser

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The development of a stablized Zeeman split laser for use in a polarization profilometer is discussed. A Hewlett-Packard laser was modified to stabilize the Zeeman split beat frequency thereby increasing the phase measurement accuracy from the Hewlett-Packard 3 degrees to an accuracy of .01 degrees. The addition of a two layered inductive winding converts the laser to a current controlled oscillator whose frequency is linearly related to coil current. This linear relationship between coil current and laser frequency permits phase locking the laser frequency to a stable crystal controlled reference frequency. The stability of the system is examined and the equipment operation procedures are outlined.

  14. Lasers in otorhinolaryngology

    NASA Astrophysics Data System (ADS)

    Pais Clemente, Manuel P.

    1992-03-01

    Lasers are now commonly accepted and widely used surgical instruments in otorhinolaryngology. There have been a great number of technological advances with lasers that have contributed to the expansion of this new surgical modality with an increased number of medical applications. Surgical strategies have also changed and are more favorable toward conservative surgery in which less tissues is removed than with more radical resections. This combination of improving technology and medical attitudes has changed the field of otorhinolaryngology, and resulted in an expanding use of laser surgery. Since 1973 we have been using the carbon dioxide laser in the treatment of diseases of the upper aero digestive systems, learning this new surgical technique from the pioneer work of Strong, Jako, and Vaughan. It is our conviction that a laser surgeon must have a thorough knowledge of laser biophysics, instrumentation, safety protocols, and surgical indications, and have the technical skills to perform laser surgery. Laser technology continues to improve at an increased speed, and it is imperative to update knowledge of current and potential applications of lasers in our specialty. It is the purpose of this article to present our clinical experience of 18 years with the use of lasers in surgery of ORL, emphasizing the carbon dioxide laser.

  15. Laser surgery: using the carbon dioxide laser.

    PubMed Central

    Wright, V. C.

    1982-01-01

    In 1917 Einstein theorized tha through an atomic process a unique kind of electromagnetic radiation could be produced by stimulated emission. When such radiation is in the optical or infrared spectrum it is termed laser (light amplification by stimulated emission of radiation) light. A laser, a high-intensity light source, emits a nearly parallel electromagnetic beam of energy at a given wavelength that can be captured by a lens and concentrated in the focal spot. The wavelength determines how the laser will be used. The carbon dioxide laser is now successfully employed for some surgical procedures in gynecology, otorhinolaryngology, neurosurgery, and plastic and general surgery. The CO2 laser beam is directed through the viewing system of an operating microscope or through a hand-held laser component. Its basic action in tissue is thermal vaporization; it causes minimal damage to adjacent tissues. Surgeons require special training in the basic methods and techniques of laser surgery, as well as in the safety standards that must be observed. Images FIG. 5 PMID:7074503

  16. Laser Synchrotron Source (LSS)

    NASA Astrophysics Data System (ADS)

    Sprangle, Philip; Ting, Antonio; Esarey, Eric; Fisher, Amon; Mourou, Gerald

    1993-02-01

    The Laser Synchrotron Source (LSS) utilizes a high peak power or high average power laser to generate within a vacuum chamber a laser beam travelling in one direction to interact with an electron beam traveling in an opposite direction in order to generate high-power x-rays. A ring resonator formed by a plurality of mirrors directs the laser beam in a closed loop to impact with the electron beam to produce x-rays. Concave mirrors in the ring resonator focus the laser beam upon the point where the laser beam interacts with the electron beam to intensify the laser energy at that point. When a Radio Frequency Linear Accelerator (RF linac) is used to produce the electron beam, x-rays having a short pulse length are generated. When a betatron is used as an electron source, x-rays having a long pulse length are generated.

  17. Laser safety in dentistry

    NASA Astrophysics Data System (ADS)

    Wigdor, Harvey A.

    1997-05-01

    One of the major causes of anxiety in the dental clinic is the dental handpiece. Because dentists wish to provide a method which can replace the drill there has often been a premature use of the laser in dentistry. Various lasers have been introduced into the clinic before research has shown the laser used is of clinical benefit. Any new treatment method must not compromise the health of the patient being treated. Thus a method of evaluating the clinical abilities of dentists and their understanding the limitations of the laser used must be developed. Dentist must be trained in the basic interaction of the laser on oral tissues. The training has to concentrate on the variation of the laser wavelength absorption in the different tissues of the oral cavity. Because of the differences in the optical properties of these tissues great care must be exercised by practitioners using lasers on patients.

  18. Laser Applications in Orthodontics

    PubMed Central

    Heidari, Somayeh; Torkan, Sepideh

    2013-01-01

    A laser is a collimated single wavelength of light which delivers a concentrated source of energy. Soon after different types of lasers were invented, investigators began to examine the effects of different wavelengths of laser energy on oral tissues, routine dental procedures and experimental applications. Orthodontists, along with other specialist in different fields of dentistry, can now benefit from several different advantages that lasers provide during the treatment process, from the beginning of the treatment, when separators are placed, to the time of resin residues removal from the tooth surface at the end of orthodontic treatment. This article outlines some of the most common usages of laser beam in orthodontics and also provides a comparison between laser and other conventional method that were the standard of care prior to the advent of laser in this field. PMID:25606324

  19. Lasers in orthodontics

    PubMed Central

    Nalcaci, Ruhi; Cokakoglu, Serpil

    2013-01-01

    Many types of dental lasers are currently available that can be efficiently used for soft and hard tissue applications in the field of orthodontics. For achieving the desired effects in the target tissue, knowledge of laser characteristics such as power, wavelength and timing, is necessary. Laser therapy is advantageous because it often avoids bleeding, can be pain free, is non-invasive and is relatively quick. The high cost is its primary disadvantage. It is very important to take the necessary precautions to prevent possible tissue damage when using laser dental systems. Here, we reviewed the main types and characteristics of laser systems used in dental practice and discuss the applications of lasers in orthodontics, harmful effects and laser system safety. PMID:24966719

  20. Raman fiber lasers

    NASA Astrophysics Data System (ADS)

    Supradeepa, V. R.; Feng, Yan; Nicholson, Jeffrey W.

    2017-02-01

    High-power fiber lasers have seen tremendous development in the last decade, with output powers exceeding multiple kilowatts from a single fiber. Ytterbium has been at the forefront as the primary rare-earth-doped gain medium owing to its inherent material advantages. However, for this reason, the lasers are largely confined to the narrow emission wavelength region of ytterbium. Power scaling at other wavelength regions has lagged significantly, and a large number of applications rely upon the diversity of emission wavelengths. Currently, Raman fiber lasers are the only known wavelength agile, scalable, high-power fiber laser technology that can span the wavelength spectrum. In this review, we address the technology of Raman fiber lasers, specifically focused on the most recent developments. We will also discuss several applications of Raman fiber lasers in laser pumping, frequency conversion, optical communications and biology.

  1. Lasers in periodontology.

    PubMed

    Mavrogiannis, M; Thomason, J M; Seymour, R A

    2004-11-01

    Since the development of the ruby laser by Maiman in 1960, lasers have been widely employed in medicine for a number of years. The purpose of this paper is to summarize potential applications for lasers in dentistry, with special regard to periodontology. This article briefly describes clinical applications of lasers and laser safety. Particularly, the use of a diode laser seems to be promising, especially in already compromised transplant patients, who need to be treated with a technique where the operative and post-operative blood loss, post-operative discomfort and the recurrence of drug-induced gingival overgrowth need to be kept to a minimum or eliminated. Therefore, the use of lasers in periodontology may lead to an alteration in present clinical practice and help to establish the best management strategy because, by maintaining periodontal health, the life quality of patients can be improved.

  2. Lasers in dentistry

    NASA Astrophysics Data System (ADS)

    Keller, Ulrich

    1991-11-01

    The infrared-laser systems like the Er:YAG, the cw CO2, the Nd:YAG, and the UV- excimer lasers are being investigated for preparing tooth-hard substances. The infrared lasers cause thermal damage to the enamel, the dentin, and the pulp with the exception of the Er:YAG laser. No thermal damage occurs using the Er:YAG laser under practical conditions because of the special thermomechanical ablation process. The ablation rates of the UV- excimer lasers are to low for practical use. Enhancing the ablation efficiency by high- repetition rates causes thermal side effects to occur. Therefore, only the Er:YAG laser has the potential to partially replace the mechanical drill.

  3. Semiconductor nanowire lasers

    NASA Astrophysics Data System (ADS)

    Eaton, Samuel W.; Fu, Anthony; Wong, Andrew B.; Ning, Cun-Zheng; Yang, Peidong

    2016-06-01

    The discovery and continued development of the laser has revolutionized both science and industry. The advent of miniaturized, semiconductor lasers has made this technology an integral part of everyday life. Exciting research continues with a new focus on nanowire lasers because of their great potential in the field of optoelectronics. In this Review, we explore the latest advancements in the development of nanowire lasers and offer our perspective on future improvements and trends. We discuss fundamental material considerations and the latest, most effective materials for nanowire lasers. A discussion of novel cavity designs and amplification methods is followed by some of the latest work on surface plasmon polariton nanowire lasers. Finally, exciting new reports of electrically pumped nanowire lasers with the potential for integrated optoelectronic applications are described.

  4. Nanofabrication with pulsed lasers.

    PubMed

    Kabashin, Av; Delaporte, Ph; Pereira, A; Grojo, D; Torres, R; Sarnet, Th; Sentis, M

    2010-02-24

    An overview of pulsed laser-assisted methods for nanofabrication, which are currently developed in our Institute (LP3), is presented. The methods compass a variety of possibilities for material nanostructuring offered by laser-matter interactions and imply either the nanostructuring of the laser-illuminated surface itself, as in cases of direct laser ablation or laser plasma-assisted treatment of semiconductors to form light-absorbing and light-emitting nano-architectures, as well as periodic nanoarrays, or laser-assisted production of nanoclusters and their controlled growth in gaseous or liquid medium to form nanostructured films or colloidal nanoparticles. Nanomaterials synthesized by laser-assisted methods have a variety of unique properties, not reproducible by any other route, and are of importance for photovoltaics, optoelectronics, biological sensing, imaging and therapeutics.

  5. Space qualified laser sources

    NASA Astrophysics Data System (ADS)

    Heine, Frank; Schwander, Thomas; Lange, Robert; Smutny, Berry

    2006-04-01

    Tesat-Spacecom has developed a series of fiber coupled single frequency lasers for space applications ranging from onboard metrology for space borne FTIR spectrometers to step tunable seed lasers for LIDAR applications. The cw-seed laser developed for the ESA AEOLUS Mission shows a 3* 10 -11 Allen variance from 1 sec time intervals up to 1000 sec. Q-switched lasers with stable beam pointing under space environments are another field of development. One important aspect of a space borne laser system is a reliable fiber coupled laser diode pump source around 808nm. A dedicated development concerning chip design and packaging yielded in a 5*10 6h MTTF (mean time to failure) for the broad area emitters. Qualification and performance test results for the different laser assemblies will be presented and their application in the different space programs.

  6. Lasers in oral surgery

    NASA Astrophysics Data System (ADS)

    Keller, Ulrich; Hibst, Raimund

    1994-12-01

    The indications of lasers in oral surgery are defined by the laser-tissue interaction types. These are mainly thermal effects depending especially on the absorption of laser light in varying biological tissues. In histological sections different laser effects are demonstrated on oral mucosa, bone and cartilage, which have a great influence on wound healing and subsequently on clinical indications of the different wavelengths. On the one hand the good coagulation effect of the Nd:YAG laser is wanted for hemostasis in soft tissue surgery. On the other hand, for the treatment of precancerous dysplasias or neoplasias an effective cutting with a coagulation effect like using the CO2 laser is necessary. However, the excision of benign mucosal lesions as well as performing osteotomies or shaping of cartilage should be undertaken with the Er:YAG laser without greater coagulation and consequently without any delay of wound healing.

  7. Micromachining with copper lasers

    NASA Astrophysics Data System (ADS)

    Knowles, Martyn R. H.; Bell, Andy; Foster-Turner, Gideon; Rutterford, Graham; Chudzicki, J.; Kearsley, Andrew J.

    1997-04-01

    In recent years the copper laser has undergone extensive development and has emerged as a leading and unique laser for micromachining. The copper laser is a high average power (10 - 250 W), high pulse repetition rate (2 - 32 kHz), visible laser (511 nm and 578 nm) that produces high peak power (typically 200 kW), short pulses (30 ns) and very good beam quality (diffraction limited). This unique set of laser parameters results in exceptional micro-machining in a wide variety of materials. Typical examples of the capabilities of the copper laser include the drilling of small holes (10 - 200 micrometer diameter) in materials as diverse as steel, ceramic, diamond and polyimide with micron precision and low taper (less than 1 degree) cutting and profiling of diamond. Application of the copper laser covers the electronic, aerospace, automotive, nuclear, medical and precision engineering industries.

  8. ORION laser target diagnostics.

    PubMed

    Bentley, C D; Edwards, R D; Andrew, J E; James, S F; Gardner, M D; Comley, A J; Vaughan, K; Horsfield, C J; Rubery, M S; Rothman, S D; Daykin, S; Masoero, S J; Palmer, J B; Meadowcroft, A L; Williams, B M; Gumbrell, E T; Fyrth, J D; Brown, C R D; Hill, M P; Oades, K; Wright, M J; Hood, B A; Kemshall, P

    2012-10-01

    The ORION laser facility is one of the UK's premier laser facilities which became operational at AWE in 2010. Its primary mission is one of stockpile stewardship, ORION will extend the UK's experimental plasma physics capability to the high temperature, high density regime relevant to Atomic Weapons Establishment's (AWE) program. The ORION laser combines ten laser beams operating in the ns regime with two sub ps short pulse chirped pulse amplification beams. This gives the UK a unique combined long pulse/short pulse laser capability which is not only available to AWE personnel but also gives access to our international partners and visiting UK academia. The ORION laser facility is equipped with a comprehensive suite of some 45 diagnostics covering optical, particle, and x-ray diagnostics all able to image the laser target interaction point. This paper focuses on a small selection of these diagnostics.

  9. Lasers in space

    NASA Astrophysics Data System (ADS)

    Michaelis, M. M.; Forbes, A.; Bingham, R.; Kellett, B. J.; Mathye, A.

    2008-05-01

    A variety of laser applications in space, past, present, future and far future are reviewed together with the contributions of some of the scientists and engineers involved, especially those that happen to have South African connections. Historically, two of the earliest laser applications in space, were atmospheric LIDAR and lunar ranging. These applications involved atmospheric physicists, several astronauts and many of the staff recruited into the Soviet and North American lunar exploration programmes. There is a strong interest in South Africa in both LIDAR and lunar ranging. Shortly after the birth of the laser (and even just prior) theoretical work on photonic propulsion and space propulsion by laser ablation was initiated by Georgii Marx, Arthur Kantrowitz and Eugen Saenger. Present or near future experimental programs are developing in the following fields: laser ablation propulsion, possibly coupled with rail gun or gas gun propulsion; interplanetary laser transmission; laser altimetry; gravity wave detection by space based Michelson interferometry; the de-orbiting of space debris by high power lasers; atom laser interferometry in space. Far future applications of laser-photonic space-propulsion were also pioneered by Carl Sagan and Robert Forward. They envisaged means of putting Saenger's ideas into practice. Forward also invented a laser based method for manufacturing solid antimatter or SANTIM, well before the ongoing experiments at CERN with anti-hydrogen production and laser-trapping. SANTIM would be an ideal propellant for interstellar missions if it could be manufactured in sufficient quantities. It would be equally useful as a power source for the transmission of information over light year distances. We briefly mention military lasers. Last but not least, we address naturally occurring lasers in space and pose the question: "did the Big Bang lase?"

  10. Laser system using ultra-short laser pulses

    DOEpatents

    Dantus, Marcos; Lozovoy, Vadim V.; Comstock, Matthew

    2009-10-27

    A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

  11. Frequency comb swept lasers

    PubMed Central

    Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C.; Fujimoto, James G.

    2010-01-01

    We demonstrate a frequency comb (FC) swept laser and a frequency comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range frequency comb filter in the swept lasers causes the lasers to generate a series of well defined frequency steps. The narrow bandwidth (0.015nm) of the frequency comb filter enables a ~−1.2dB sensitivity roll off over ~3mm range, compared to conventional swept source and FDML lasers which have −10dB and −5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0–3mm appear aliased back into the principal range. In addition, the frequency comb output from the lasers are equally spaced in frequency (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier transformation of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed. PMID:19997365

  12. Laser treatment in gynecology

    NASA Astrophysics Data System (ADS)

    de Riese, Cornelia

    2004-07-01

    This presentation is designed as a brief overview of laser use in gynecology, for non-medical researchers involved in development of new laser techniques. The literature of the past decade is reviewed. Differences in penetration, absorption, and suitable delivery media for the beams dictate clinical application. The use of CO2 laser in the treatment of uterine cervical intraepithelial lesions is well established and indications as well as techniques have not changed over 30 years. The Cochrane Systematic Review from 2000 suggests no obviously superior technique. CO2 laser ablation of the vagina is also established as a safe treatment modality for VAIN. CO2 laser permits treatment of lesions with excellent cosmetic and functional results. The treatment of heavy menstrual bleeding by destruction of the endometrial lining using various techniques has been the subject of a 2002 Cochran Database Review. Among the compared treatment modalities are newer and modified laser techniques. Conclusion by reviewers is that outcomes and complication profiles of newer techniques compare favorably with the gold standard of endometrial resection. The ELITT diode laser system is one of the new successful additions. CO2 laser is also the dominant laser type used with laparoscopy for ablation of endometriotic implants. Myoma coagulation or myolysis with Nd:Yag laser through the laparoscope or hysteroscope is a conservative treatment option. Even MRI guided percutaneous approaches have been described. No long-term data are available.

  13. Photobiomodulation in laser surgery

    NASA Astrophysics Data System (ADS)

    Liu, Timon Cheng-Yi; Rong, Dong-Liang; Huang, Jin; Deng, Xiao-Yuan; Liu, Song-Hao

    2006-01-01

    Laser surgery provides good exposure with clear operating fields and satisfactory preliminary functional results. In contrast to conventional excision, it was found that matrix metalloproteinases and the tissue inhibitors of metalloproteinases -1 mRNA expression is higher, myofibroblasts appeared and disappeared slower in laser excision wounds. It has been suggested that the better anatomical and functional results achieved following laser cordectomy may be explained by the fact that such procedures result in better, more rapid healing processes to recover vocal cord for early glottic tumors and better. In this paper, the role of photobiomodulation in laser surgery will be discussed by the cultured monolayer normal human skin fibroblast model of the photobiomodulation of marginal irradiation of high intensity laser beam, the photobiomodulation related to the irradiated tissue, the biological information model of photobiomodulation and the animal models of laser surgery. Although high intensity laser beam is so intense that it destroys the irradiated cells or tissue, its marginal irradiation intensity is so low that there is photobiomodulation on non-damage cells to modulate the regeneration of partly damaged tissue so that the surgery of laser of different parameters results in different post-surgical recovery. It was concluded that photobiomodulation might play an important role in the long-term effects of laser surgery, which might be used to design laser surgery.

  14. Frequency comb swept lasers.

    PubMed

    Tsai, Tsung-Han; Zhou, Chao; Adler, Desmond C; Fujimoto, James G

    2009-11-09

    We demonstrate a frequency comb (FC) swept laser and a frequency comb Fourier domain mode locked (FC-FDML) laser for applications in optical coherence tomography (OCT). The fiber-based FC swept lasers operate at a sweep rate of 1kHz and 120kHz, respectively over a 135nm tuning range centered at 1310nm with average output powers of 50mW. A 25GHz free spectral range frequency comb filter in the swept lasers causes the lasers to generate a series of well defined frequency steps. The narrow bandwidth (0.015nm) of the frequency comb filter enables a approximately -1.2dB sensitivity roll off over approximately 3mm range, compared to conventional swept source and FDML lasers which have -10dB and -5dB roll offs, respectively. Measurements at very long ranges are possible with minimal sensitivity loss, however reflections from outside the principal measurement range of 0-3mm appear aliased back into the principal range. In addition, the frequency comb output from the lasers are equally spaced in frequency (linear in k-space). The filtered laser output can be used to self-clock the OCT interference signal sampling, enabling direct fast Fourier transformation of the fringe signals, without the need for fringe recalibration procedures. The design and operation principles of FC swept lasers are discussed and designs for short cavity lasers for OCT and interferometric measurement applications are proposed.

  15. Lasers in medicine

    NASA Astrophysics Data System (ADS)

    Peng, Qian; Juzeniene, Asta; Chen, Jiyao; Svaasand, Lars O.; Warloe, Trond; Giercksky, Karl-Erik; Moan, Johan

    2008-05-01

    It is hard to imagine that a narrow, one-way, coherent, moving, amplified beam of light fired by excited atoms is powerful enough to slice through steel. In 1917, Albert Einstein speculated that under certain conditions atoms could absorb light and be stimulated to shed their borrowed energy. Charles Townes coined the term laser (light amplification by stimulated emission of radiation) in 1951. Theodore Maiman investigated the glare of a flash lamp in a rod of synthetic ruby, creating the first human-made laser in 1960. The laser involves exciting atoms and passing them through a medium such as crystal, gas or liquid. As the cascade of photon energy sweeps through the medium, bouncing off mirrors, it is reflected back and forth, and gains energy to produce a high wattage beam of light. Although lasers are today used by a large variety of professions, one of the most meaningful applications of laser technology has been through its use in medicine. Being faster and less invasive with a high precision, lasers have penetrated into most medical disciplines during the last half century including dermatology, ophthalmology, dentistry, otolaryngology, gastroenterology, urology, gynaecology, cardiology, neurosurgery and orthopaedics. In many ways the laser has revolutionized the diagnosis and treatment of a disease. As a surgical tool the laser is capable of three basic functions. When focused on a point it can cauterize deeply as it cuts, reducing the surgical trauma caused by a knife. It can vaporize the surface of a tissue. Or, through optical fibres, it can permit a doctor to see inside the body. Lasers have also become an indispensable tool in biological applications from high-resolution microscopy to subcellular nanosurgery. Indeed, medical lasers are a prime example of how the movement of an idea can truly change the medical world. This review will survey various applications of lasers in medicine including four major categories: types of lasers, laser

  16. Laser Safety Inspection Criteria

    SciTech Connect

    Barat, K

    2005-02-11

    A responsibility of the Laser Safety Officer (LSO) is to perform laser safety audits. The American National Standard Z136.1 Safe use of Lasers references this requirement in several sections: (1) Section 1.3.2 LSO Specific Responsibilities states under Hazard Evaluation, ''The LSO shall be responsible for hazards evaluation of laser work areas''; (2) Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''; and (3) Appendix D, under Survey and Inspections, it states, ''the LSO will survey by inspection, as considered necessary, all areas where laser equipment is used''. Therefore, for facilities using Class 3B and or Class 4 lasers, audits for laser safety compliance are expected to be conducted. The composition, frequency and rigueur of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms. In many institutions, a sole Laser Safety Officer (LSO) or a number of Deputy LSO's perform these audits. For that matter, there are institutions that request users to perform a self-assessment audit. Many items on the common audit list and the associated findings are subjective because they are based on the experience and interest of the LSO or auditor in particular items on the checklist. Beam block usage is an example; to one set of eyes a particular arrangement might be completely adequate, while to another the installation may be inadequate. In order to provide more consistency, the National Ignition Facility Directorate at Lawrence Livermore National Laboratory (NIF-LLNL) has established criteria for a number of items found on the typical laser safety audit form. These criteria are distributed to laser users, and they serve two broad purposes: first, it gives the user an expectation of what will be reviewed by an auditor, and second, it is an

  17. Laser materials production

    NASA Astrophysics Data System (ADS)

    Gianinoni, I.; Musci, M.

    1985-09-01

    The characteristics and the perspectives of the new photochemical laser techniques for materials production will be briefly analysed and some recent experimental results both on large area deposition of thin films and on synthesis of powders will be reported. As an example of an IR laser process, the cw CO 2 laser-induced deposition of hydrogenated amorphous silicon will be described in some detail. The results of some UV experiments for semiconductor, metal and insulating film depositions will also be discussed. The features of the process for laser-driven synthesis of powders and the characteristics of the produced particles will be evidenced, and some of their technological applications will be outlined. The requirements of the laser sources suitable for this kind of applications are in general the same as in gas-phase laser chemistry, however it will be pointed out how some parameters are more significant for this specific use.

  18. Pulsed excimer laser processing

    NASA Technical Reports Server (NTRS)

    Wong, D.

    1985-01-01

    The status of pulsed excimer laser processing of PV cells is presented. The cost effective feasibility of fabricating high efficiency solar cells on Czochralski wafers using a pulsed excimer laser for junction formation, surface passivation, and front metallization. Laser annealing results were promising with the best AR coated cell having an efficiency of 16.1%. Better results would be expected with larger laser spot size because there was some degradation in open circuit voltage caused by laser spot overlap and edge effects. Surface heating and photolytic decomposition by the laser was used to deposit tungsten from the reaction of tungsten hexafluoride and hydrogen. The line widths were 5 to 10 mils, and the depositions passed the tape adhesion test. Thinner lines are practical using an optimized optical system.

  19. Pulsed excimer laser processing

    NASA Astrophysics Data System (ADS)

    Wong, D.

    1985-06-01

    The status of pulsed excimer laser processing of PV cells is presented. The cost effective feasibility of fabricating high efficiency solar cells on Czochralski wafers using a pulsed excimer laser for junction formation, surface passivation, and front metallization. Laser annealing results were promising with the best AR coated cell having an efficiency of 16.1%. Better results would be expected with larger laser spot size because there was some degradation in open circuit voltage caused by laser spot overlap and edge effects. Surface heating and photolytic decomposition by the laser was used to deposit tungsten from the reaction of tungsten hexafluoride and hydrogen. The line widths were 5 to 10 mils, and the depositions passed the tape adhesion test. Thinner lines are practical using an optimized optical system.

  20. Laser/tissue interaction.

    PubMed

    Dederich, D N

    1991-01-01

    When laser light impinges on tissue, it can reflect, scatter, be absorbed, or transmit to the surrounding tissue. Absorption controls to a great degree the extent to which reflection, scattering and transmission occur, and wavelength is the primary determinant of absorption. The CO2 laser is consistently absorbed by most materials and tissues and the Nd-YAG laser wavelength is preferentially absorbed in pigmented tissues. The factors which determine the initial tissue effect include the laser wavelength, laser power, laser waveform, tissue optical properties, and tissue thermal properties. There are almost an infinite number of combinations of these factors possible, many of which would result in unacceptable damage to the tissues. This underscores the need to thoroughly test any particular combination of these factors on the conceptual, in-vitro, and in-vivo level before a treatment is offered.

  1. Photonic Crystal Microchip Laser.

    PubMed

    Gailevicius, Darius; Koliadenko, Volodymyr; Purlys, Vytautas; Peckus, Martynas; Taranenko, Victor; Staliunas, Kestutis

    2016-09-29

    The microchip lasers, being very compact and efficient sources of coherent light, suffer from one serious drawback: low spatial quality of the beam strongly reducing the brightness of emitted radiation. Attempts to improve the beam quality, such as pump-beam guiding, external feedback, either strongly reduce the emission power, or drastically increase the size and complexity of the lasers. Here it is proposed that specially designed photonic crystal in the cavity of a microchip laser, can significantly improve the beam quality. Experiments show that a microchip laser, due to spatial filtering functionality of intracavity photonic crystal, improves the beam quality factor M(2) reducing it by a factor of 2, and increase the brightness of radiation by a factor of 3. This comprises a new kind of laser, the "photonic crystal microchip laser", a very compact and efficient light source emitting high spatial quality high brightness radiation.

  2. Synthetic laser medium

    DOEpatents

    Stokowski, S.E.

    1987-10-20

    A laser medium is particularly useful in high average power solid state lasers. The laser medium includes a chromium dopant and preferably neodymium ions as codopant, and is primarily a gadolinium scandium gallium garnet, or an analog thereof. Divalent cations inhibit spiral morphology as large boules from which the laser medium is derived are grown, and a source of ions convertible between a trivalent state and a tetravalent state at a low ionization energy are in the laser medium to reduce an absorption coefficient at about one micron wavelength otherwise caused by the divalent cations. These divalent cations and convertible ions are dispersed in the laser medium. Preferred convertible ions are provided from titanium or cerium sources.

  3. Synthetic laser medium

    DOEpatents

    Stokowski, Stanley E.

    1989-01-01

    A laser medium is particularly useful in high average power solid state lasers. The laser medium includes a chormium dopant and preferably neodymium ions as codopant, and is primarily a gadolinium scandium gallium garnet, or an analog thereof. Divalent cations inhibit spiral morphology as large boules from which the laser medium is derived are grown, and a source of ions convertible between a trivalent state and a tetravalent state at a low ionization energy are in the laser medium to reduce an absorption coefficient at about one micron wavelength otherwise caused by the divalent cations. These divalent cations and convertible ions are dispersed in the laser medium. Preferred convertible ions are provided from titanium or cerium sources.

  4. Nanofabrication with Pulsed Lasers

    PubMed Central

    2010-01-01

    An overview of pulsed laser-assisted methods for nanofabrication, which are currently developed in our Institute (LP3), is presented. The methods compass a variety of possibilities for material nanostructuring offered by laser–matter interactions and imply either the nanostructuring of the laser-illuminated surface itself, as in cases of direct laser ablation or laser plasma-assisted treatment of semiconductors to form light-absorbing and light-emitting nano-architectures, as well as periodic nanoarrays, or laser-assisted production of nanoclusters and their controlled growth in gaseous or liquid medium to form nanostructured films or colloidal nanoparticles. Nanomaterials synthesized by laser-assisted methods have a variety of unique properties, not reproducible by any other route, and are of importance for photovoltaics, optoelectronics, biological sensing, imaging and therapeutics. PMID:20672069

  5. Laser rocket system analysis

    NASA Technical Reports Server (NTRS)

    Jones, W. S.; Forsyth, J. B.; Skratt, J. P.

    1979-01-01

    The laser rocket systems investigated in this study were for orbital transportation using space-based, ground-based and airborne laser transmitters. The propulsion unit of these systems utilizes a continuous wave (CW) laser beam focused into a thrust chamber which initiates a plasma in the hydrogen propellant, thus heating the propellant and providing thrust through a suitably designed nozzle and expansion skirt. The specific impulse is limited only by the ability to adequately cool the thruster and the amount of laser energy entering the engine. The results of the study showed that, with advanced technology, laser rocket systems with either a space- or ground-based laser transmitter could reduce the national budget allocated to space transportation by 10 to 345 billion dollars over a 10-year life cycle when compared to advanced chemical propulsion systems (LO2-LH2) of equal capability. The variation in savings depends upon the projected mission model.

  6. Micro-laser

    DOEpatents

    Hutchinson, Donald P.; Richards, Roger K.

    2003-07-22

    A micro-laser is disclosed which includes a waveguide, a first and a second subwavelength resonant grating in the waveguide, and at least one photonic band gap resonant structure (PBG) in the waveguide and at least one amplifying medium in the waveguide. PBG features are positioned between the first and second subwavelength resonant gratings and allow introduction of amplifying mediums into the highly resonant guided micro-laser microcavity. The micro-laser may be positioned on a die of a bulk substrate material with one or more electronic and optical devices and may be communicably connected to the same. A method for fabricating a micro-laser is disclosed. A method for tuning the micro-laser is also disclosed. The micro-laser may be used as an optical regenerator, or a light source for data transfer or for optical computing.

  7. Lasers in periodontics

    PubMed Central

    Elavarasu, Sugumari; Naveen, Devisree; Thangavelu, Arthiie

    2012-01-01

    Laser is one of the most captivating technologies in dental practice since Theodore Maiman in 1960 invented the ruby laser. Lasers in dentistry have revolutionized several areas of treatment in the last three and a half decades of the 20th century. Introduced as an alternative to mechanical cutting device, laser has now become an instrument of choice in many dental applications. Evidence suggests its use in initial periodontal therapy, surgery, and more recently, its utility in salvaging implant opens up a wide range of applications. More research with better designs are a necessity before lasers can become a part of dental armamentarium. This paper gives an insight to laser in periodontics. PMID:23066266

  8. Portable laser laboratory

    NASA Astrophysics Data System (ADS)

    Weir, J. T.

    1994-07-01

    A Portable Laser Laboratory (PLL) is being designed and built for the CALIOPE Program tests which will begin in October of 1994. The PLL is designed to give maximum flexibility for evolving laser experiments and can be readily moved by loading it onto a standard truck trailer. The internal configuration for the October experiments will support a two line DIAL system running in the mid-IR. Brief descriptions of the laser and detection systems are included.

  9. Thallium Mercury Laser Development

    DTIC Science & Technology

    1981-01-01

    THALLIUM MERCURY LASER DEVELOPMENT C. S. Liu and D. W. Feldman FINAL REPORT (PHASE III) (Period between Feb. 1, 1980 and Jan. 31, 1981) 0 Contract No...Pittsburgh, Pennsylvania 15235 Approved for public release;IDistribution Unlimited 1/i;THALLIUM MERCURY LASER DEVELOPMENT * , , IS C. S./Liu tRD. W /eldman...9 ’ t4 THALLIUM MERCURY LASER DEVELOPMENT C. S. Liu and D. W. Feldman Westinghouse R&D Center Pittsburgh, Pennsylvania 15235 1

  10. Excimer laser chemical problems

    SciTech Connect

    Tennant, R.; Peterson, N.

    1982-01-01

    Techniques need to be developed to maintain XeF and XeCl laser performance over long periods of time without degradation resulting from chemical processes occurring within the laser. The dominant chemical issues include optical damage, corrosions of laser materials, gas contamination, and control of halogen concentration. Each of these issues are discussed and summarized. The methods of minimizing or controlling the chemical processes involved are presented.

  11. Diode Pumped Fiber Laser

    DTIC Science & Technology

    1983-07-01

    acousto - optic beam deflector for greater absolute accuracy. The detection system was also upgraded to a response time of • 1 usec. The... 2 C. SUMMARY OF RESULTS.., 3 D . GENERAL PLAN 5 II. Nd:YAG FIBER PREPARATION 7 A. FIBER GROWTH 7 B. PHYSICAL PROPERTIES OF Nd:YAG...A. INTRODUCTION 25 B. GENERAL FORMALISM 26 C. FREE-SPACE LASERS 35 D . FIBER LASERS 43 1. Fiber Laser Configuration 43 2 . F

  12. Laser In Veterinary Medicine

    NASA Astrophysics Data System (ADS)

    Newman, Carlton; Jaggar, David H.

    1982-12-01

    Lasers have been used for some time now on animals for experimental purposes prior to their use in human medical and surgical fields. However the use of lasers in veterinary medicine and surgery per se is a recent development. We describe the application of high and low intensity laser technology in a general overview of the current uses, some limitations to its use and future needs for future inquiry and development.

  13. Polarization feedback laser stabilization

    DOEpatents

    Esherick, P.; Owyoung, A.

    1987-09-28

    A system for locking two Nd:YAG laser oscillators includes an optical path for feeding the output of one laser into the other with different polarizations. Elliptical polarization is incorporated into the optical path so that the change in polarization that occurs when the frequencies coincide may be detected to provide a feedback signal to control one laser relative to the other. 4 figs.

  14. Precision laser aiming system

    DOEpatents

    Ahrens, Brandon R.; Todd, Steven N.

    2009-04-28

    A precision laser aiming system comprises a disrupter tool, a reflector, and a laser fixture. The disrupter tool, the reflector and the laser fixture are configurable for iterative alignment and aiming toward an explosive device threat. The invention enables a disrupter to be quickly and accurately set up, aligned, and aimed in order to render safe or to disrupt a target from a standoff position.

  15. Etalon laser diode

    SciTech Connect

    Allen, L.B.; Koenig, H.G.; Rice, R.R.

    1981-08-18

    A laser diode is disclosed that is suitable for integrated and fiber optic applications requiring single transverse and single longitudinal mode operation. The single transverse mode is provided by making a gallium arsenide double heterostructural laser diode with a narrow stripe width and a relatively long length. The single longitudinal mode operation is provided by cracking the diode transverse to the stripe at one or more locations to form internal etalons in the laser cavity.

  16. Laser cutting plastic materials

    SciTech Connect

    Van Cleave, R.A.

    1980-08-01

    A 1000-watt CO/sub 2/ laser has been demonstrated as a reliable production machine tool for cutting of plastics, high strength reinforced composites, and other nonmetals. More than 40 different plastics have been laser cut, and the results are tabulated. Applications for laser cutting described include fiberglass-reinforced laminates, Kevlar/epoxy composites, fiberglass-reinforced phenolics, nylon/epoxy laminates, ceramics, and disposable tooling made from acrylic.

  17. Gigashot Optical Laser Demonstrator

    SciTech Connect

    Deri, R. J.

    2015-10-13

    The Gigashot Optical Laser Demonstrator (GOLD) project has demonstrated a novel optical amplifier for high energy pulsed lasers operating at high repetition rates. The amplifier stores enough pump energy to support >10 J of laser output, and employs conduction cooling for thermal management to avoid the need for expensive and bulky high-pressure helium subsystems. A prototype amplifier was fabricated, pumped with diode light at 885 nm, and characterized. Experimental results show that the amplifier provides sufficient small-signal gain and sufficiently low wavefront and birefringence impairments to prove useful in laser systems, at repetition rates up to 60 Hz.

  18. Laser Gyro Theory Extension.

    DTIC Science & Technology

    1980-12-01

    7 AA096 14S ARI ZONA UNIV TUCSON OPTICA SCIENCES CENTER F/6 20/5 LASER GYRO THE.ORY ESTENS ION(U)7 C So M 0 SCULLY IF33615-79-C-17N4 UNCLASSIIED...GYRO We have been working with scientists at Litton Industries in the development of a Zeeman laser gyro (ZLAG). We have developed a vector laser...Hutchings and V. Sanders are with Litton Industries , Woodland rate measurements with laser gyros (Section II). The remain- Hills, CA 91364. ing

  19. Shuttle Laser Altimeter

    NASA Technical Reports Server (NTRS)

    Bufton, Jack L.; Harding, David J.; Garvin, James B.

    1999-01-01

    The Shuttle Laser Altimeter (SLA) is a Hitchhiker experiment that has flown twice; first on STS-72 in January 1996 and then on STS-85 in August 1997. Both missions produced successful laser altimetry and surface lidar data products from approximately 80 hours per mission of SLA data operations. A total of four Shuttle missions are planned for the SLA series. This paper documents SLA mission results and explains SLA pathfinder accomplishments at the mid-point in this series of Hitchhiker missions. The overall objective of the SLA mission series is the transition of the Goddard Space Flight Center airborne laser altimeter and lidar technology to low Earth orbit as a pathfinder for NASA operational space-based laser remote sensing devices. Future laser altimeter sensors will utilize systems and approaches being tested with SLA, including the Multi-Beam Laser Altimeter (MBLA) and the Geoscience Laser Altimeter System (GLAS). MBLA is the land and vegetation laser sensor for the NASA Earth System Sciences Pathfinder Vegetation Canopy Lidar (VCL) Mission, and GLAS is the Earth Observing System facility instrument on the Ice, Cloud, and Land Elevation Satellite (ICESat). The Mars Orbiting Laser Altimeter, now well into a multi-year mapping mission at the red planet, is also directly benefiting from SLA data analysis methods, just as SLA benefited from MOLA spare parts and instrument technology experience [5] during SLA construction in the early 1990s.

  20. SYMMETRICAL LASER CRYSTALS.

    DTIC Science & Technology

    CRYSTAL GROWTH , SYMMETRY(CRYSTALLOGRAPHY), LASERS, SYNTHESIS, FERROELECTRIC CRYSTALS , FLUORESCENCE, IMPURITIES, BARIUM COMPOUNDS, ZIRCONATES...STRONTIUM COMPOUNDS, TITANATES, STANNATES, SAMARIUM, MANGANESE, REFRACTORY MATERIALS, OXIDES, SINGLE CRYSTALS .

  1. A quantum laser pointer.

    PubMed

    Treps, Nicolas; Grosse, Nicolai; Bowen, Warwick P; Fabre, Claude; Bachor, Hans-A; Lam, Ping Koy

    2003-08-15

    The measurement sensitivity of the pointing direction of a laser beam is ultimately limited by the quantum nature of light. To reduce this limit, we have experimentally produced a quantum laser pointer, a beam of light whose direction is measured with a precision greater than that possible for a usual laser beam. The laser pointer is generated by combining three different beams in three orthogonal transverse modes, two of them in a squeezed-vacuum state and one in an intense coherent field. The result provides a demonstration of multichannel spatial squeezing, along with its application to the improvement of beam positioning sensitivity and, more generally, to imaging.

  2. Laser Surface Treatment

    NASA Astrophysics Data System (ADS)

    Gnanamuthu, D. S.

    1980-10-01

    Experimental procedures and current state-of-the-art are presented for laser surface treating methods such as alloying, cladding, grain refining, and transformation hardening using a cw CO2 laser. Microstructural and x-ray analyses of the treated surfaces indicate that a laser beam can locally enhance surface properties. Laser alloying offers the possibility to selectively modify a low cost workpiece surface so that it has the desired high quality surface properties characteristic of high performance alloys. Laser cladding offers feasibility to apply high melting cladding alloys on low melting workpieces, to reduce the amount of dilution of cladding alloy with the workpieces, and the potential to apply dense ceramic claddings to metallic workpieces. Laser grain refining offers potential to either minimize or eliminate surface defects such as inclusions, intermetallic compounds, and pores, and to provide a refined grain structure. Laser transformation hardening provides the treated workpieces with a hard martensitic surface that has compressive stresses for enhanced fatigue life; in addition, reduction in wear rate of treated surfaces is achieved. This experimental study indicates that the use of lasers for surface treatment has several limitations. Further studies will provide better understanding for maximum utilization of laser surface treating processes.

  3. Dental lasers and science.

    PubMed

    Zakariasen, K L; Dederich, D N

    1991-07-01

    We have attempted to accomplish two purposes in this article. First, we have presented the case that extensive scientific investigation must form the base of our profession, that it must be an ongoing, continuous process and that laser dentistry must be developed through extensive scientific inquiry--as all of our treatment modalities should be. Second, we have presented many examples of the science involved in the development of laser dentistry. Lasers do have far-reaching potential for application to dentistry. We, as a profession, must insist that such laser development is done properly, not foisted upon us based on anecdotal reports and incomplete research.

  4. Deep space laser communications

    NASA Astrophysics Data System (ADS)

    Biswas, Abhijit; Kovalik, Joseph M.; Srinivasan, Meera; Shaw, Matthew; Piazzolla, Sabino; Wright, Malcolm W.; Farr, William H.

    2016-03-01

    A number of laser communication link demonstrations from near Earth distances extending out to lunar ranges have been remarkably successful, demonstrating the augmented channel capacity that is accessible with the use of lasers for communications. The next hurdle on the path to extending laser communication and its benefits throughout the solar system and beyond is to demonstrate deep-space laser communication links. In this paper, concepts and technology development being advanced at the Jet Propulsion Laboratory (JPL) in order to enable deep-space link demonstrations to ranges of approximately 3 AU in the next decade, will be discussed.

  5. Optofluidic random laser

    NASA Astrophysics Data System (ADS)

    Shivakiran Bhaktha, B. N.; Bachelard, Nicolas; Noblin, Xavier; Sebbah, Patrick

    2012-10-01

    Random lasing is reported in a dye-circulated structured polymeric microfluidic channel. The role of disorder, which results from limited accuracy of photolithographic process, is demonstrated by the variation of the emission spectrum with local-pump position and by the extreme sensitivity to a local perturbation of the structure. Thresholds comparable to those of conventional microfluidic lasers are achieved, without the hurdle of state-of-the-art cavity fabrication. Potential applications of optofluidic random lasers for on-chip sensors are discussed. Introduction of random lasers in the field of optofluidics is a promising alternative to on-chip laser integration with light and fluidic functionalities.

  6. Spaceborne laser radar.

    NASA Technical Reports Server (NTRS)

    Flom, T.

    1972-01-01

    Development of laser systems to acquire and track targets in applications such as the rendezvous and docking of two spacecraft. A scan technique is described whereby a narrow laser beam is simultaneously scanned with an equally narrow receiver field-of-view without the aid of mechanical gimbals. Equations are developed in order to examine the maximum acquisition and tracking rates, and the maximum target range for a scanning laser radar system. A recently built prototype of a small, lightweight, low-power-consuming scanning laser radar is described.

  7. Laser eye protection

    NASA Astrophysics Data System (ADS)

    Allen, Ralph G.; Labo, Jack A.; Mayo, Michael W.

    1990-07-01

    Laser applications have proliferated in recent years and as to be expected their presence is no longer confined to the laboratory or places where access to their radiation can be easily controlled. One obvious application where this is so is in military operations where various devices such as laser range finders target designators and secure communications equipment elevate the risk of exposure specifically eye exposure to unacceptable levels. Although the need for eye protection in the laboratory and other controlled areas has been appreciated since the invention of the laser the use of lasers in circumstances where safety or the risk of temporary loss of vision which can not always be ensured by administrative procedures has made adequate eye protection essential. It is the critical nature of many military operations that has driven the search for eye protection against both nuclear and laser radiation. At the same time the requirement to maintain useful vision during irradiation as well as advances in laser technology have complicated the problem enormously. Pertinent aspects of the problem such as laser characteristics- -pulse width repetition rate laser wavelength tunability or agility as well as laser power or energy have been placed in perspective. In addition possible effects on vision for various exposures have been estimated as have the characteristics required of eye protective devices. Various classes of devices are discussed and advantages and disadvantages noted. 1.

  8. Trends in laser micromachining

    NASA Astrophysics Data System (ADS)

    Gaebler, Frank; van Nunen, Joris; Held, Andrew

    2016-03-01

    Laser Micromachining is well established in industry. Depending on the application lasers with pulse length from μseconds to femtoseconds and wavelengths from 1064nm and its harmonics up to 5μm or 10.6μm are used. Ultrafast laser machining using pulses with pico or femtosecond duration pulses is gaining traction, as it offers very precise processing of materials with low thermal impact. Large-scale industrial ultrafast laser applications show that the market can be divided into various sub segments. One set of applications demand low power around 10W, compact footprint and are extremely sensitive to the laser price whilst still demanding 10ps or shorter laser pulses. A second set of applications are very power hungry and only become economically feasible for large scale deployments at power levels in the 100+W class. There is also a growing demand for applications requiring fs-laser pulses. In our presentation we would like to describe these sub segments by using selected applications from the automotive and electronics industry e.g. drilling of gas/diesel injection nozzles, dicing of LED substrates. We close the presentation with an outlook to micromachining applications e.g. glass cutting and foil processing with unique new CO lasers emitting 5μm laser wavelength.

  9. Fusion reactor pumped laser

    DOEpatents

    Jassby, Daniel L.

    1988-01-01

    A nuclear pumped laser capable of producing long pulses of very high power laser radiation is provided. A toroidal fusion reactor provides energetic neutrons which are slowed down by a moderator. The moderated neutrons are converted to energetic particles capable of pumping a lasing medium. The lasing medium is housed in an annular cell surrounding the reactor. The cell includes an annular reflecting mirror at the bottom and an annular output window at the top. A neutron reflector is disposed around the cell to reflect escaping neutrons back into the cell. The laser radiation from the annular window is focused onto a beam compactor which generates a single coherent output laser beam.

  10. Lasers and avionic integration

    NASA Astrophysics Data System (ADS)

    Willams, J. S.

    1983-07-01

    Interrogative applications of laser technology are considered, taking into account the extent to which a centralized source of information can be used to service a number of functions which need to be performed in an airframe, and, in addition, also the potential of the laser as probing device. Aspects of laser technology and air vehicle communications are discussed along with laser based techniques for processing and storage of information. Attention is given to data transmission within the aircraft, communications external to the air vehicle, Fourier optics, holographic methods, real-time processing, Bragg cells and spectrum analysis, optical bistable devices, and optical data storage.

  11. Laser applications in phlebology

    NASA Astrophysics Data System (ADS)

    Longo, Leonardo; Mancini, S.; Postiglione, Marco; Postiglione, M. G.

    2001-06-01

    PURPOSE: review of laser used in phlebology METHOD: critical analysis of scientific data taken from the literature and based on 25 years personal experience. RESULTS: we have three groups of laser applications in phlebology: for the diagnosis, as physical therapy and as surgical therapy. DISCUSSION AND CONCLUSION: the laser-doppler studies the microcirculations, the no-surgical therapy shown positive results in the treatment of venous ulcers and for the wound healing. It could be indicate also as antiphlogistic and anti-edema therapy, in superficial thrombophlebitis. The surgical laser is useful for the surgical cleaning of ulcers, for haemorroids, angiomas and telangiectases.

  12. Laser adaptive holographic hydrophone

    SciTech Connect

    Romashko, R V; Kulchin, Yu N; Bezruk, M N; Ermolaev, S A

    2016-03-31

    A new type of a laser hydrophone based on dynamic holograms, formed in a photorefractive crystal, is proposed and studied. It is shown that the use of dynamic holograms makes it unnecessary to use complex optical schemes and systems for electronic stabilisation of the interferometer operating point. This essentially simplifies the scheme of the laser hydrophone preserving its high sensitivity, which offers the possibility to use it under a strong variation of the environment parameters. The laser adaptive holographic hydrophone implemented at present possesses the sensitivity at a level of 3.3 mV Pa{sup -1} in the frequency range from 1 to 30 kHz. (laser hydrophones)

  13. Lighting with laser diodes

    NASA Astrophysics Data System (ADS)

    Basu, Chandrajit; Meinhardt-Wollweber, Merve; Roth, Bernhard

    2013-08-01

    Contemporary white light-emitting diodes (LEDs) are much more efficient than compact fluorescent lamps and hence are rapidly capturing the market for general illumination. LEDs are also replacing halogen lamps or even newer xenon based lamps in automotive headlamps. Because laser diodes are inherently much brighter and often more efficient than corresponding LEDs, there is great research interest in developing laser diode based illumination systems. Operating at higher current densities and with smaller form factors, laser diodes may outperform LEDs in the future. This article reviews the possibilities and challenges in the integration of visible laser diodes in future illumination systems.

  14. Laser processing with specially designed laser beam

    NASA Astrophysics Data System (ADS)

    Asratyan, A. A.; Bulychev, N. A.; Feofanov, I. N.; Kazaryan, M. A.; Krasovskii, V. I.; Lyabin, N. A.; Pogosyan, L. A.; Sachkov, V. I.; Zakharyan, R. A.

    2016-04-01

    The possibility of using laser systems to form beams with special spatial configurations has been studied. The laser systems applied had a self-conjugate cavity based on the elements of copper vapor lasers (LT-5Cu, LT-10Cu, LT-30Cu) with an average power of 5, 10, or 30 W. The active elements were pumped by current pulses of duration 80-100 ns. The duration of laser generation pulses was up to 25 ns. The generator unit included an unstable cavity, where one reflector was a special mirror with a reflecting coating. Various original optical schemes used were capable of exploring spatial configurations and energy characteristics of output laser beams in their interaction with micro- and nanoparticles fabricated from various materials. In these experiments, the beam dimensions of the obtained zones varied from 0.3 to 5 µm, which is comparable with the minimum permissible dimensions determined by the optical elements applied. This method is useful in transforming a large amount of information at the laser pulse repetition rate of 10-30 kHz. It was possible to realize the high-precision micromachining and microfabrication of microscale details by direct writing, cutting and drilling (with the cutting width and through-hole diameters ranging from 3 to 100 µm) and produce microscale, deep, intricate and narrow grooves on substrate surfaces of metals and nonmetal materials. This system is used for producing high-quality microscale details without moving the object under treatment. It can also be used for microcutting and microdrilling in a variety of metals such as molybdenum, copper and stainless steel, with a thickness of up to 300 µm, and in nonmetals such as silicon, sapphire and diamond with a thickness ranging from 10 µm to 1 mm with different thermal parameters and specially designed laser beam.

  15. Laser Program annual report 1987

    SciTech Connect

    O'Neal, E.M.; Murphy, P.W.; Canada, J.A.; Kirvel, R.D.; Peck, T.; Price, M.E.; Prono, J.K.; Reid, S.G.; Wallerstein, L.; Wright, T.W.

    1989-07-01

    This report discusses the following topics: target design and experiments; target materials development; laboratory x-ray lasers; laser science and technology; high-average-power solid state lasers; and ICF applications studies.

  16. Laser peening with fiber optic delivery

    DOEpatents

    Friedman, Herbert W.; Ault, Earl R.; Scheibner, Karl F.

    2004-11-16

    A system for processing a workpiece using a laser. The laser produces at least one laser pulse. A laser processing unit is used to process the workpiece using the at least one laser pulse. A fiber optic cable is used for transmitting the at least one laser pulse from the laser to the laser processing unit.

  17. Robotic Laser Coating Removal System

    DTIC Science & Technology

    2008-08-01

    completion of this evaluation a 6 kW CO2 laser from Rofin -Sinar was selected for use in the RLCRS. This laser provided the highest quality laser ...DATA AND ASSUMPTIONS................................................................B-1 iii LIST OF FIGURES Page Figure 1. Six kW CO2 laser ...for proposal (RFP) that was distributed throughout the laser industry. In response to this RFP, 15 laser systems (nine CO2 , three Nd:YAG, and three

  18. Laser surgery of the skin.

    PubMed

    Goldberg, D J

    1989-11-01

    The carbon dioxide laser, the argon laser and the pulse-dye laser are used to remove a variety of skin lesions. Advantages of laser surgery include a relatively bloodless operating field and minimal postoperative discomfort and swelling. Warts, tattoos, actinic cheilitis, skin cancer, xanthelasma, ingrown toenails, keloids and port-wine stains are among the lesions that can be removed with laser surgery. The tunable pulse-dye laser is particularly useful in the treatment of vascular lesions.

  19. High power solid state lasers

    SciTech Connect

    Weber, H.

    1988-01-01

    These proceedings discuss the following subjects: trends in materials processing with laser radiation; slabs and high power systems; glasses and new crystals; solid state lasers at HOYA Corp.; lamps, resonators and transmission; glasses as active materials for high average power solid state lasers; flashlamp pumped GGG-crystals; alexandrite lasers; designing telescope resonators; mode operation of neodymium: YAG lasers; intracavity frequency doubling with KTP crystal and thermal effects in cylinder lasers.

  20. Compact Ho:YLF Laser

    NASA Technical Reports Server (NTRS)

    Hemmati, H.

    1988-01-01

    Longitudinal pumping by laser diodes increases efficiency. Improved holmium:yttrium lithium fluoride laser radiates as much as 56 mW of power at wavelength of 2.1 micrometer. New Ho:YLF laser more compact and efficient than older, more powerful devices of this type. Compact, efficient Ho:YLF laser based on recent successes in use of diode lasers to pump other types of solid-state lasers.

  1. High-power pulsed lasers

    SciTech Connect

    Holzrichter, J.F.

    1980-04-02

    The ideas that led to the successful construction and operation of large multibeam fusion lasers at the Lawrence Livermore Laboratory are reviewed. These lasers are based on the use of Nd:glass laser materials. However, most of the concepts are applicable to any laser being designed for fusion experimentation. This report is a summary of lectures given by the author at the 20th Scottish University Summer School in Physics, on Laser Plasma Interaction. This report includes basic concepts of the laser plasma system, a discussion of lasers that are useful for short-pulse, high-power operation, laser design constraints, optical diagnostics, and system organization.

  2. Lasers '83. Proceedings of the international conference

    SciTech Connect

    Powell, R.C.

    1985-01-01

    Among the topics discussed are the development history of the semiconductor diode laser, laser material processing, nonlinear spectroscopy, recent advancements in diode lasers, laser-driven particle accelerators, laser applications in the atmospheric sciences, laser-assisted collisions, novel (garnet and alexandrite) solid state laser materials, IR molecular lasers, devices and components for fiber-optic communications, free-electron lasers and masers, and picosecond optical phenomena. Also covered are laser-stimulated materials surface processes, color center laser developments, blue-green and metal vapor lasers, laser chemistry, nonlinear effects, high energy lasers, excimer lasers, laser trapping of ions, optical cavities and propagation, laser isotope separation, laser trapping of atoms, laser applications in biochemistry, tunable coherent short wavelength radiation, laser spectroscopy, picosecond studies of condensed phase molecular systems, and combustion and plasma diagnostics.

  3. Tunable dysprosium laser.

    PubMed

    Majewski, Matthew R; Jackson, Stuart D

    2016-10-01

    We report the demonstration of a tunable dysprosium laser. The experiment employed in-band pumping of a Dy3+-doped fluoride fiber and a simple resonator design involving a ruled diffraction grating. The laser produced tuning between 2.95 and 3.35 μm, limited by the availability of optics.

  4. Dye laser amplifier

    DOEpatents

    Moses, E.I.

    1992-12-01

    An improved dye laser amplifier is disclosed. The efficiency of the dye laser amplifier is increased significantly by increasing the power of a dye beam as it passes from an input window to an output window within the dye chamber, while maintaining the intensity of the dye beam constant. 3 figs.

  5. Laser Ranging Simulation Program

    NASA Technical Reports Server (NTRS)

    Piazolla, Sabino; Hemmati, Hamid; Tratt, David

    2003-01-01

    Laser Ranging Simulation Program (LRSP) is a computer program that predicts selected aspects of the performances of a laser altimeter or other laser ranging or remote-sensing systems and is especially applicable to a laser-based system used to map terrain from a distance of several kilometers. Designed to run in a more recent version (5 or higher) of the MATLAB programming language, LRSP exploits the numerical and graphical capabilities of MATLAB. LRSP generates a graphical user interface that includes a pop-up menu that prompts the user for the input of data that determine the performance of a laser ranging system. Examples of input data include duration and energy of the laser pulse, the laser wavelength, the width of the laser beam, and several parameters that characterize the transmitting and receiving optics, the receiving electronic circuitry, and the optical properties of the atmosphere and the terrain. When the input data have been entered, LRSP computes the signal-to-noise ratio as a function of range, signal and noise currents, and ranging and pointing errors.

  6. Athermal laser design.

    PubMed

    Bovington, Jock; Srinivasan, Sudharsanan; Bowers, John E

    2014-08-11

    This paper discusses circuit based and waveguide based athermalization schemes and provides some design examples of athermalized lasers utilizing fully integrated athermal components as an alternative to power hungry thermo-electric controllers (TECs), off-chip wavelength lockers or monitors with lookup tables for tunable lasers. This class of solutions is important for uncooled transmitters on silicon.

  7. Surface treatments by laser

    NASA Astrophysics Data System (ADS)

    Thomann, A. L.; Benzerga, R.; Basillais, Armelle; Georges, Cecile; Fariaut, Francois; Semmar, Nadjib; Boulmer-Leborgne, Chantal

    2003-07-01

    Laser treatments of various metals are studying depending on the laser wavelength, pulse time duration and shape, and fluence (laser/metal interaction regime). Low fluence excimer UV laser melting process of gold layer is shown to improve the corrosion resistance of multilayer (Au/Ni/Cu alloy) electrical contacts. For this application the homogenity of the laser beam as well as the initial Cu substrate roughness are found to be limiting parameters of the process. Carburization of Al alloy, performed in C3H6 atmosphere with a KrF laser induces the incorporation of carbon atoms over about 4 μm depth. The crystalline Al4C3 synthesized at the surface leads to a strengthening of the light Al alloy, which is of great interest for application in car industry. The study shows that diffusion of C atom in the target is possible because of a plasma presence on the surface which supports the molten bath life time and induces dissociation of the ambient gas. In the last example of laser metal surface treatment presented in that paper, a commonly used steel is treated in air with different lasers at a fluence above the plasma formation threshold. It is seen that the machining oils covering the surface before the treatment can be efficiently removed and that new compounds (nitride, carbide and oxides) are formed at the surface.

  8. CO2 laser resurfacing.

    PubMed

    Fitzpatrick, R E

    2001-07-01

    The CO2 Laser offers a variety of unique features in resurfacing facial photodamage and acne scarring. These include hemostasis, efficient removal of the epidermis in a single pass, thermally induced tissue tightening, and safe, predictable tissue interaction. Knowledge of these mechanisms will result in the capability of using the CO2 laser effectively and safely whether the goal is superficial or deep treatment.

  9. Learning about Lasers

    ERIC Educational Resources Information Center

    Roberts, Larry

    2011-01-01

    The word laser is an acronym. It stands for Light Amplification by Stimulated Emission of Radiation. Lasers, invented in 1958, are used to cut and fuse materials, accurately survey long distances, communicate across fiber-optic phone lines, produce 3D pictures, make special effects, help navigation, and read bar codes for cash registers. A laser…

  10. Free-Electron Lasers.

    ERIC Educational Resources Information Center

    Brau, Charles A.

    1988-01-01

    Describes the use of free-electron lasers as a source of coherent radiation over a broad range of wavelengths from the far-infrared to the far-ultraviolet regions of the spectrum. Discusses some applications of these lasers, including medicine and strategic defense. (TW)

  11. Dielectric laser accelerators

    NASA Astrophysics Data System (ADS)

    England, R. Joel; Noble, Robert J.; Bane, Karl; Dowell, David H.; Ng, Cho-Kuen; Spencer, James E.; Tantawi, Sami; Wu, Ziran; Byer, Robert L.; Peralta, Edgar; Soong, Ken; Chang, Chia-Ming; Montazeri, Behnam; Wolf, Stephen J.; Cowan, Benjamin; Dawson, Jay; Gai, Wei; Hommelhoff, Peter; Huang, Yen-Chieh; Jing, Chunguang; McGuinness, Christopher; Palmer, Robert B.; Naranjo, Brian; Rosenzweig, James; Travish, Gil; Mizrahi, Amit; Schachter, Levi; Sears, Christopher; Werner, Gregory R.; Yoder, Rodney B.

    2014-10-01

    The use of infrared lasers to power optical-scale lithographically fabricated particle accelerators is a developing area of research that has garnered increasing interest in recent years. The physics and technology of this approach is reviewed, which is referred to as dielectric laser acceleration (DLA). In the DLA scheme operating at typical laser pulse lengths of 0.1 to 1 ps, the laser damage fluences for robust dielectric materials correspond to peak surface electric fields in the GV /m regime. The corresponding accelerating field enhancement represents a potential reduction in active length of the accelerator between 1 and 2 orders of magnitude. Power sources for DLA-based accelerators (lasers) are less costly than microwave sources (klystrons) for equivalent average power levels due to wider availability and private sector investment. Because of the high laser-to-particle coupling efficiency, required pulse energies are consistent with tabletop microJoule class lasers. Combined with the very high (MHz) repetition rates these lasers can provide, the DLA approach appears promising for a variety of applications, including future high-energy physics colliders, compact light sources, and portable medical scanners and radiative therapy machines.

  12. Lasers, A Bibliography.

    DTIC Science & Technology

    1979-09-02

    TA1675 Muncheryan , Hrand 14. Laser Fundamentals and Applications, 1486 Indianapolis , IN: H.W. Sams , c1975 . 2...Francisco , CA: the cmd , 1970. • TK787 1.3 Van Pelt , W.F . , et al . Laser Fundamentals and Experiments . US Washington , DC: U.S. Bur of Radiological

  13. Infrared laser bone ablation

    SciTech Connect

    Nuss, R.C.; Fabian, R.L.; Sarkar, R.; Puliafito, C.A.

    1988-01-01

    The bone ablation characteristics of five infrared lasers, including three pulsed lasers (Nd:YAG, lambda = 1064 micron; Hol:YSGG, lambda = 2.10 micron; and Erb:YAG, lambda = 2.94 micron) and two continuous-wave lasers (Nd:YAG, lambda = 1.064 micron; and CO/sub 2/, lambda = 10.6 micron), were studied. All laser ablations were performed in vitro, using moist, freshly dissected calvarium of guinea pig skulls. Quantitative etch rates of the three pulsed lasers were calculated. Light microscopy of histologic sections of ablated bone revealed a zone of tissue damage of 10 to 15 micron adjacent to the lesion edge in the case of the pulsed Nd:YAG and the Erb:YAG lasers, from 20 to 90 micron zone of tissue damage for bone ablated by the Hol:YSGG laser, and 60 to 135 micron zone of tissue damage in the case of the two continuous-wave lasers. Possible mechanisms of bone ablation and tissue damage are discussed.

  14. Coaxial short pulsed laser

    DOEpatents

    Nelson, M.A.; Davies, T.J.

    1975-08-01

    This invention relates to a laser system of rugged design suitable for use in a field environment. The laser itself is of coaxial design with a solid potting material filling the space between components. A reservoir is employed to provide a gas lasing medium between an electrode pair, each of which is connected to one of the coaxial conductors. (auth)

  15. Focusing laser scanner

    NASA Technical Reports Server (NTRS)

    Callen, W. R.; Weaver, J. E.

    1979-01-01

    Economical laser scanner assembled from commercially available components, modulates and scans focused laser beam over area up to 5.1 by 5.1 cm. Scanner gives resolution comparable to that of conventional television. Device is highly applicable to area of analog and digital storage and retrieval.

  16. Laser hair removal pearls.

    PubMed

    Tierney, Emily P; Goldberg, David J

    2008-03-01

    A number of lasers and light devices are now available for the treatment of unwanted hair. The goal of laser hair removal is to damage stem cells in the bulge of the follicle through the targeting of melanin, the endogenous chromophore for laser and light devices utilized to remove hair. The competing chromophores in the skin and hair, oxyhemoglobin and water, have a decreased absorption between 690 nm and 1000 nm, thus making this an ideal range for laser and light sources. Pearls of laser hair removal are presented in this review, focusing on four areas of recent development: 1 treatment of blond, white and gray hair; 2 paradoxical hypertrichosis; 3 laser hair removal in children; and 4 comparison of lasers and IPL. Laser and light-based technologies to remove hair represents one of the most exciting areas where discoveries by dermatologists have led to novel treatment approaches. It is likely that in the next decade, continued advancements in this field will bring us closer to the development of a more permanent and painless form of hair removal.

  17. Explosively pumped laser light

    DOEpatents

    Piltch, Martin S.; Michelotti, Roy A.

    1991-01-01

    A single shot laser pumped by detonation of an explosive in a shell casing. The shock wave from detonation of the explosive causes a rare gas to luminesce. The high intensity light from the gas enters a lasing medium, which thereafter outputs a pulse of laser light to disable optical sensors and personnel.

  18. Green pumped Alexandrite lasers

    NASA Astrophysics Data System (ADS)

    Kuper, Jerry W.; Brown, David C.

    2005-04-01

    Initial experiments with pulsed and CW pumping an alexandrite laser rod at 532 nm are presented. This pumping architecture holds promise for the production of scalable diode-pumped, tunable alexandrite laser systems operating in the near infrared (750 nm), and the ultraviolet (375 and 250 nm) spectral regions.

  19. Silicon Stokes terahertz laser

    SciTech Connect

    Pavlov, S. G.; Huebers, H.-W.; Hovenier, J. N.; Klaassen, T. O.; Carder, D. A.; Phillips, P. J.; Redlich, B.; Riemann, H.; Zhukavin, R. Kh.; Shastin, V. N.

    2007-04-10

    A Raman-type silicon laser at terahertz frequencies has been realized. Stokes-shifted stimulated emission has been observed from silicon crystals doped by antimony donors when optically excited by an infrared free electron laser. The Raman lasing was obtained due to resonant scattering on electronic states of a donor atom.

  20. Laser beam generating apparatus

    DOEpatents

    Warner, B.E.; Duncan, D.B.

    1994-02-15

    Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus is described. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect). 7 figures.

  1. Liquid heat capacity lasers

    DOEpatents

    Comaskey, Brian J.; Scheibner, Karl F.; Ault, Earl R.

    2007-05-01

    The heat capacity laser concept is extended to systems in which the heat capacity lasing media is a liquid. The laser active liquid is circulated from a reservoir (where the bulk of the media and hence waste heat resides) through a channel so configured for both optical pumping of the media for gain and for light amplification from the resulting gain.

  2. Laser biostimulation in pediatrics

    NASA Astrophysics Data System (ADS)

    Utz, Irina A.; Lagutina, L. E.; Tuchin, Valery V.

    1995-01-01

    In the present paper the method and apparatus for percutaneous laser irradiation of blood (PLIB) in vessels (veins) are described. Results of clinical investigations of biostimulating effects under PLIB by red laser light (633 nm) in Cubiti and Saphena Magna veins are presented.

  3. Lasers for Training Devices.

    ERIC Educational Resources Information Center

    Fuller, C. A.

    A breadboard model of a laser display system is described in detail and its operating procedure is outlined. The system consists of: a Model 52 argon krypton ion laser and power supply; an optical breadboard comprising a pocket cell light modulator, a galvonmeter beam deflector for vertical scanning, a unique multiple reflection beam steerer for…

  4. Laser energy conversion

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1989-01-01

    The conversion of laser energy to other, more useful, forms is an important element of any space power transmission system employing lasers. In general the user, at the receiving sight, will require the energy in a form other than laser radiation. In particular, conversion to rocket power and electricity are considered to be two major areas where one must consider various conversion techniques. Three systems (photovoltaic cells, MHD generators, and gas turbines) have been identified as the laser-to-electricity conversion systems that appear to meet most of the criteria for a space-based system. The laser thruster also shows considerable promise as a space propulsion system. At this time one cannot predict which of the three laser-to-electric converters will be best suited to particular mission needs. All three systems have some particular advantages, as well as disadvantages. It would be prudent to continue research on all three systems, as well as the laser rocket thruster. Research on novel energy conversion systems, such as the optical rectenna and the reverse free-electron laser, should continue due to their potential for high payoff.

  5. Laser Programs Highlight 1995

    SciTech Connect

    Jacobs, R.R.

    1997-01-31

    Our contributions to laser science and technology and corresponding applications range from concept to design of the National Ignition Facility, transfer of Atomic Vapor Laser Isotope Separation technology to the private sector, and from new initiatives in industry and defense to micro-optics for improving human vision.

  6. Solid state laser

    NASA Technical Reports Server (NTRS)

    Rines, Glen A. (Inventor); Moulton, Peter F. (Inventor); Harrison, James (Inventor)

    1993-01-01

    A wavelength-tunable, injection-seeded, dispersion-compensated, dispersively-pumped solid state laser includes a lasing medium; a highly reflective mirror; an output coupler; at least one isosceles Brewster prism oriented to the minimum deviation angle between the medium and the mirror for directing light of different wavelengths along different paths; means for varying the angle of the highly reflective mirror relative to the light from at least one Brewster angle for selecting a predetermined laser operating wavelength; a dispersion compensation apparatus associated with the lasing medium; a laser injection seeding port disposed between the dispersion compensation apparatus and one of the mirror and coupler and including a reflective surface at an acute non-Brewster angle to the laser beam for introducing a seed input; a dispersion compensation apparatus associated with the laser medium including opposite chirality optical elements; the lasing medium including a pump surface disposed at an acute angle to the laser beam to define a discrete path for the pumping laser beam separate from the pumped laser beam.

  7. Tunable Infrared Semiconductor Lasers

    DTIC Science & Technology

    2013-12-20

    is a thulium fiber laser that has output of 20Watts at 1.908 µm with a collimated output beam diameter of about 5 mm. With a cylindrical lens, a...the device onto a copper heat sink and then to the cold finger of liquid nitrogen Dewar. In characterization, a thulium fiber laser at 1.908 nm

  8. Lasers in periodontal therapy.

    PubMed

    Passanezi, Euloir; Damante, Carla Andreotti; de Rezende, Maria L Rubo; Greghi, Sebastião L Aguiar

    2015-02-01

    About 50 years ago, lasers started to be used in periodontal treatment following evidence that wounds produced in animals healed more quickly after being irradiated with low-intensity lasers. Increased production of growth factors, stimulated mainly by red and infrared lasers, may participate in this process by influencing the behavior of various types of cells. High-intensity lasers have been used as an alternative to nonsurgical periodontal therapy in root biomodification and to reduce dentin hypersensivity; low-intensity lasers are frequently employed to improve tissue repair in regenerative procedures and in antimicrobial photodynamic therapy. Despite the abundance of promising data on the advantages of their use, there is still controversy regarding the real benefits of lasers and antimicrobial photodynamic therapy in periodontal and peri-implant treatment. A huge variation in the parameters of laser application among studies makes comparisons very difficult. An overview of the current concepts and findings on lasers in periodontal therapy is presented with emphasis on data collected from Latin-American researchers.

  9. Laser beam generating apparatus

    DOEpatents

    Warner, B.E.; Duncan, D.B.

    1993-12-28

    Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect). 11 figures.

  10. Longitudinal discharge laser electrodes

    DOEpatents

    Warner, B.E.; Miller, J.L.; Ault, E.R.

    1994-08-23

    The improved longitudinal discharge laser electrode with IR baffle includes an electrode made up of washers spaced along the laser axis in order to form inter-washer spaces for hollow cathode discharge to take place and for IR radiation to be trapped. Additional IR baffles can be placed between the electrode ann the window. 2 figs.

  11. Longitudinal discharge laser electrodes

    DOEpatents

    Warner, Bruce E.; Miller, John L.; Ault, Earl R.

    1994-01-01

    The improved longitudinal discharge laser electrode with IR baffle includes an electrode made up of washers spaced along the laser axis in order to form inter-washer spaces for hollow cathode discharge to take place and for IR radiation to be trapped. Additional IR baffles can be placed between the electrode ann the window.

  12. Ceramic laser materials

    NASA Astrophysics Data System (ADS)

    Ikesue, Akio; Aung, Yan Lin

    2008-12-01

    The word 'ceramics' is derived from the Greek keramos, meaning pottery and porcelain. The opaque and translucent cement and clay often used in tableware are not appropriate for optical applications because of the high content of optical scattering sources, that is, defects. Recently, scientists have shown that by eliminating the defects, a new, refined ceramic material - polycrystalline ceramic - can be produced. This advanced ceramic material offers practical laser generation and is anticipated to be a highly attractive alternative to conventional glass and single-crystal laser technologies in the future. Here we review the history of the development of ceramic lasers, the principle of laser generation based on this material, some typical results achieved with ceramic lasers so far, and discuss the potential future outlook for the field.

  13. Photonic Crystal Microchip Laser

    NASA Astrophysics Data System (ADS)

    Gailevicius, Darius; Koliadenko, Volodymyr; Purlys, Vytautas; Peckus, Martynas; Taranenko, Victor; Staliunas, Kestutis

    2016-09-01

    The microchip lasers, being very compact and efficient sources of coherent light, suffer from one serious drawback: low spatial quality of the beam strongly reducing the brightness of emitted radiation. Attempts to improve the beam quality, such as pump-beam guiding, external feedback, either strongly reduce the emission power, or drastically increase the size and complexity of the lasers. Here it is proposed that specially designed photonic crystal in the cavity of a microchip laser, can significantly improve the beam quality. Experiments show that a microchip laser, due to spatial filtering functionality of intracavity photonic crystal, improves the beam quality factor M2 reducing it by a factor of 2, and increase the brightness of radiation by a factor of 3. This comprises a new kind of laser, the “photonic crystal microchip laser”, a very compact and efficient light source emitting high spatial quality high brightness radiation.

  14. Laser controlled flame stabilization

    DOEpatents

    Early, James W.; Thomas, Matthew E.

    2001-01-01

    A method and apparatus is provided for initiating and stabilizing fuel combustion in applications such as gas turbine electrical power generating engines and jet turbine engines where it is desired to burn lean fuel/air mixtures which produce lower amounts of NO.sub.x. A laser induced spark is propagated at a distance from the fuel nozzle with the laser ignitor being remotely located from the high temperature environment of the combustion chamber. A laser initiating spark generated by focusing high peak power laser light to a sufficiently tight laser spot within the fuel to cause the ionization of air and fuel into a plasma is unobtrusive to the flow dynamics of the combustion chamber of a fuel injector, thereby facilitating whatever advantage can be taken of flow dynamics in the design of the fuel injector.

  15. Laser hair removal.

    PubMed

    Ibrahimi, Omar A; Avram, Mathew M; Hanke, C William; Kilmer, Suzanne L; Anderson, R Rox

    2011-01-01

    The extended theory of selective photothermolysis enables the laser surgeon to target and destroy hair follicles, thereby leading to hair removal. Today, laser hair removal (LHR) is the most commonly requested cosmetic procedure in the world and is routinely performed by dermatologists, other physicians, and non-physician personnel with variable efficacy. The ideal candidate for LHR is fair skinned with dark terminal hair; however, LHR can today be successfully performed in all skin types. Knowledge of hair follicle anatomy and physiology, proper patient selection and preoperative preparation, principles of laser safety, familiarity with the various laser/light devices, and a thorough understanding of laser-tissue interactions are vital to optimizing treatment efficacy while minimizing complications and side effects.

  16. Laser-heated thruster

    NASA Technical Reports Server (NTRS)

    Kemp, N. H.; Krech, R. H.

    1980-01-01

    The development of computer codes for the thrust chamber of a rocket of which the propellant gas is heated by a CW laser beam was investigated. The following results are presented: (1) simplified models of laser heated thrusters for approximate parametric studies and performance mapping; (3) computer programs for thrust chamber design; and (3) shock tube experiment to measure absorption coefficients. Two thrust chamber design programs are outlined: (1) for seeded hydrogen, with both low temperature and high temperature seeds, which absorbs the laser radiation continuously, starting at the inlet gas temperature; and (2) for hydrogen seeded with cesium, in which a laser supported combustion wave stands near the gas inlet, and heats the gas up to a temperature at which the gas can absorb the laser energy.

  17. Photonic Crystal Microchip Laser

    PubMed Central

    Gailevicius, Darius; Koliadenko, Volodymyr; Purlys, Vytautas; Peckus, Martynas; Taranenko, Victor; Staliunas, Kestutis

    2016-01-01

    The microchip lasers, being very compact and efficient sources of coherent light, suffer from one serious drawback: low spatial quality of the beam strongly reducing the brightness of emitted radiation. Attempts to improve the beam quality, such as pump-beam guiding, external feedback, either strongly reduce the emission power, or drastically increase the size and complexity of the lasers. Here it is proposed that specially designed photonic crystal in the cavity of a microchip laser, can significantly improve the beam quality. Experiments show that a microchip laser, due to spatial filtering functionality of intracavity photonic crystal, improves the beam quality factor M2 reducing it by a factor of 2, and increase the brightness of radiation by a factor of 3. This comprises a new kind of laser, the “photonic crystal microchip laser”, a very compact and efficient light source emitting high spatial quality high brightness radiation. PMID:27683066

  18. Regenerative similariton laser

    NASA Astrophysics Data System (ADS)

    North, Thibault; Brès, Camille-Sophie

    2016-05-01

    Self-pulsating lasers based on cascaded reshaping and reamplification (2R) are capable of initiating ultrashort pulses despite the accumulation of large amounts of nonlinearities in all-fiber resonators. The spectral properties of pulses in self-similar propagation are compatible with cascaded 2R regeneration by offset filtering, making parabolic pulses suitable for the design of a laser of this recently introduced class. A new type of regenerative laser giving birth to similaritons is numerically investigated and shows that this laser is the analog of regenerative sources based solely on self-phase modulation and offset filtering. The regenerative similariton laser does not suffer from instabilities due to excessive nonlinearities and enables ultrashort pulse generation in a simple cavity configuration.

  19. NASA Space Laser Technology

    NASA Technical Reports Server (NTRS)

    Krainak, Michael A.

    2015-01-01

    Over the next two decades, the number of space based laser missions for mapping, spectroscopy, remote sensing and other scientific investigations will increase several fold. The demand for high wall-plug efficiency, low noise, narrow linewidth laser systems to meet different systems requirements that can reliably operate over the life of a mission will be high. The general trends will be for spatial quality very close to the diffraction limit, improved spectral performance, increased wall-plug efficiency and multi-beam processing. Improved spectral performance will include narrower spectral width (very near the transform limit), increased wavelength stability and or tuning (depending on application) and lasers reaching a wider range of wavelengths stretching into the mid-infrared and the near ultraviolet. We are actively developing high efficiency laser transmitter and high-sensitivity laser receiver systems that are suitable for spaceborne applications.

  20. Catalac free electron laser

    DOEpatents

    Brau, C.A.; Swenson, D.A.; Boyd, T.J. Jr.

    1979-12-12

    A catalac free electron laser using a rf linac (catalac) which acts as a catalyst to accelerate an electron beam in an initial pass through the catalac and decelerate the electron beam during a second pass through the catalac is described. During the second pass through the catalac, energy is extracted from the electron beam and transformed to energy of the accelerating fields of the catalac to increase efficiency of the device. Various embodiments disclose the use of post linacs to add electron beam energy extracted by the wiggler and the use of supplementary catalacs to extract energy at various energy peaks produced by the free electron laser wiggler to further enhance efficiency of the catalac free electron laser. The catalac free electron laser can be used in conjunction with a simple resonator, a ring resonator, or as an amplifier in conjunction with a master oscillator laser.

  1. Catalac free electron laser

    DOEpatents

    Brau, Charles A.; Swenson, Donald A.; Boyd, Jr., Thomas J.

    1982-01-01

    A catalac free electron laser using a rf linac (catalac) which acts as a catalyst to accelerate an electron beam in an initial pass through the catalac and decelerate the electron beam during a second pass through the catalac. During the second pass through the catalac, energy is extracted from the electron beam and transformed to energy of the accelerating fields of the catalac to increase efficiency of the device. Various embodiments disclose the use of post linacs to add electron beam energy extracted by the wiggler and the use of supplementary catalacs to extract energy at various energy peaks produced by the free electron laser wiggler to further enhance efficiency of the catalac free electron laser. The catalac free electron laser can be used in conjunction with a simple resonator, a ring resonator or as an amplifier in conjunction with a master oscillator laser.

  2. Laser driven radiography

    SciTech Connect

    Perry, M.D.; Sefcik, J.; Cowan, T.

    1997-12-20

    Intense laser (> 1021 W/cm{sup 3}) driven hard x-ray sources offer a new alternative to conventional electron accelerator Bremsstrahlung sources. These laser driven sources offer considerable simplicity in design and potential cost advantage for multiple axis views. High spatial and temporal resolution is achievable as a result of the very small source size (<100 um) and short-duration of the laser pulse. We have begun a series of experiments with the Petawatt laser at LLNL to determine the photon flux achievable with these sources and assess their potential for Stewardship applications. Additionally, we are developing a conceptual design and cost estimate of a multi-pulse, multi-axis (up to five) radiographic facility utilizing the Contained Firing Facility at site 300 and existing laser hardware.

  3. Solid State Laser

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Titan-CW Ti:sapphire (titanium-doped sapphire) tunable laser is an innovation in solid-state laser technology jointly developed by the Research and Solid State Laser Divisions of Schwartz Electro-optics, Inc. (SEO). SEO is producing the laser for the commercial market, an outgrowth of a program sponsored by Langley Research Center to develop Ti:sapphire technology for space use. SEO's Titan-CW series of Ti:sapphire tunable lasers have applicability in analytical equipment designed for qualitative analysis of carbohydrates and proteins, structural analysis of water, starch/sugar analyses, and measurements of salt in meat. Further applications are expected in semiconductor manufacture, in medicine for diagnosis and therapy, and in biochemistry.

  4. Laser Cleaning of Gildings

    NASA Astrophysics Data System (ADS)

    Panzner, M.; Wiedemann, G.; Meier, M.; Conrad, W.; Kempe, A.; Hutsch, T.

    Results of laser cleaning experiments on different gilding types like leaf gilding and fire gilding are presented in this contribution by means of three tested art objects. The reflectivity of gold is advantageously high for the typical laser cleaning wavelength of 1,064 nm. Additionally, to avoid damage like gold loss, the transfer of the absorbed laser pulse energy into the art object by thermal conduction is considered. Fire gilded surfaces are most easily cleaned because of the good heat transfer conditions which imply a high threshold intensity with respect to damage. This is different for leaf gilded surfaces but suitable laser cleaning parameters have also been found for this case. The results of laser cleaning experiments are presented by photography, microscopy, SEM and EDX analysis.

  5. Auricular Acupuncture with Laser

    PubMed Central

    Bahr, Frank

    2013-01-01

    Auricular acupuncture is a method which has been successfully used in various fields of medicine especially in the treatment of pain relief. The introduction of lasers especially low-level lasers into medicine brought besides the already existing stimulation with needles and electricity an additional technique to auricular acupuncture. This literature research looks at the historical background, the development and the anatomical and neurological aspects of auricular acupuncture in general and auricular laser acupuncture in detail. Preliminary scientific findings on auricular acupuncture with laser have been described in detail and discussed critically in this review article. The results of the studies have shown evidence of the effect of auricular laser acupuncture. However, a comparison of these studies was impossible due to their different study designs. The most important technical as well as study parameters were described in detail in order to give more sufficient evidence and to improve the quality of future studies. PMID:23935695

  6. Pulsed IR inductive lasers

    NASA Astrophysics Data System (ADS)

    Razhev, A. M.; Churkin, D. S.; Kargapol'tsev, E. S.

    2014-07-01

    Pulsed inductive discharge is a new alternative method of pumping active gas laser media. The work presents results of experimental investigations of near, mid, and far IR inductive gas lasers (H2, HF, and CO2) operating at different transitions of atoms and molecules with different mechanisms of formation of inversion population. The excitation systems of a pulsed inductive cylindrical discharge (pulsed inductively coupled plasma) and pulsed RF inductive discharge in the gases are developed. Various gas mixtures including H2, N2, He, Ne, F2, NF3, and SF6 are used. Characteristics of near IR H2 laser radiation are investigated. Maximal pulse peak power of 7 kW is achieved. The possibility of using a pulsed inductive discharge as a new method of pumping HF laser active medium is demonstrated. The pulsed RF inductive CO2 laser is created and a total efficiency of 17% is achieved.

  7. Laser dividing apparatus

    DOEpatents

    English, Jr., R. Edward; Johnson, Steve A.

    1995-01-01

    A laser beam dividing apparatus (10) having a first beam splitter (14) with an aperture (16) therein positioned in the path of a laser beam (12) such that a portion of the laser beam (12) passes through the aperture (16) onto a second beam splitter (20) and a portion of the laser beam (12) impinges upon the first beam splitter (14). Both the first beam splitter (14) and the second beam splitter (20) are, optionally, made from a dichroic material such that a green component (24) of the laser beam (12) is reflected therefrom and a yellow component (26) is refracted therethrough. The first beam splitter (14) and the second beam splitter (20) further each have a plurality of facets (22) such that the components (24, 26) are reflected and refracted in a number equaling the number of facets (22).

  8. Silicon Nanocrystal Laser

    SciTech Connect

    Yu, J

    2005-03-09

    The purpose of this feasibility study project was to attempt to demonstrate the silicon-nanocrystal-based laser. Such a silicon laser (made using conventional silicon-manufacturing technologies) would provide the crucial missing link that would enable a completely-silicon-based photonic system. We prepared thin layers of silicon nanocrystal material by ion-implanting Si in fused silica substrates, followed by a high temperature anneal process. These Si nanocrystals produced intense photoluminescence when optically pumped with ultraviolet light. Laser structures based on Fabry-Perot cavity and distributed feedback (DFB) designs were fabricated using the Si nanocrystals as the ''lasing'' medium. We optically pumped the samples with CW lasers at 413nm wavelength to quickly assess the feasibility of making lasers out of the Nanocrystal Si material and to verify the gain coefficients reported by other research groups.

  9. Ultrafast laser IR countermeasures

    NASA Astrophysics Data System (ADS)

    Rafailov, Michael K.

    2009-05-01

    Directional Infrared Countermeasures (DIRCM) is an effective technique to defeat heat-seeking missiles. The major problem of existing DIRCM is that it may work like a beacon for threats that are not susceptible to the jamming code implemented: attracting a missile instead of re-directing it away from the aircraft. Ultra-fast laser pulse technology is discussed as an alternative to a conventional laser DIRCM. An ultra-fast laser is capable of providing a different type of countermeasure which is compatible with existing laser based DIRCM pointing systems as it requires much less peak power than damage inducing systems. A foundation of ultra-fast technology is its unique ability to alter the intrinsic characteristics of the semiconductor. In this paper, we will only consider the effects of a mild lattice disturbance caused by relatively low energy ultra-fast (femto-second) and, to some extent, fast (pico-second) laser pulses.

  10. Free electron laser designs for laser amplification

    DOEpatents

    Prosnitz, Donald; Szoke, Abraham

    1985-01-01

    Method for laser beam amplification by means of free electron laser techniques. With wiggler magnetic field strength B.sub.w and wavelength .lambda..sub.w =2.pi./k.sub.w regarded as variable parameters, the method(s) impose conditions such as substantial constancy of B.sub.w /k.sub.w or k.sub.w or B.sub.w and k.sub.w (alternating), coupled with a choice of either constant resonant phase angle or programmed phase space "bucket" area.

  11. Laser autodyne angioscopy

    NASA Astrophysics Data System (ADS)

    Gordov, Eugeni P.; Makogon, Michail M.; Pekarskii, Vikentii V.; Shipulin, Vladimir M.

    1994-07-01

    A novel approach to imagination of inner surface of arteria during performing laser and balloon angioplasty is suggested. To this end the laser light was transmitted via fiber to the zone of interest and radiation diffused by the walls of the vessel was adopted by receiver. Known technique to determine of contours of an object by measuring the time of the laser pulse propagation is unusable due to the small geometrical scales. Using the CW laser and feeding a portion of the backscattered signal power into the laser cavity (this kind of device was referred to as laser autodyne coherent receiver), the authors have been able to measure the object contour with spatial resolution of up to 2 microns. Such resolution and high sensitivity inherent to this technique should allows one to detect early in the development of the atherosclerosis. To obtain the 3D image of the vessel inside surface we offer two methods. In the first case the vessel side is scanned by moving the end of light quid. In the second one multimode laser is used and the image is drawing by scanning the transverse modes of this laser. The vessel side and atherosclerotic plaques have the different reflectivity spectrum and this fact can be used to increase the image contrast. The correct selection of the laser wavelength makes possible to work into the vessel with circulation of the blood. The calculation of laser autodyne intrascope performance and tentative experimental results are presented in this report. The advantages of this method for the angiography are in speed and adequately of control during performing angioplasty.

  12. Laser conservation paleontology

    NASA Astrophysics Data System (ADS)

    Asmus, John F.

    2001-10-01

    Just as lasers have found countless applications in science, industry, medicine, and entertainment, an array of real and potential uses for lasers in art-conservation analytes and practice have been investigated over the past thirty years. These include holographic recording, holographic recording, holographic nondestructive testing, laser-induced ultrasonic imaging, laser-scattering surface characterization, atomic and molecular analyses, photoacoustic spectroscopy, surface modification, as well as surface divestment and cleaning. The initial endeavors in exploring and assessing the utility of these tools for art conservation are recounted for investigations involving ruby, glass, ion, YAG, carbon dioxide, dye, and excimer lasers as well as high-intensity nonlaser light generators such as xenon flashlamps and argon pinchlamps. Initially, laser divestment/cleaning was, by general consensus, the least plausible laser application in art conservation. In the past ten years it has emerged to dominate all the other applications noted above. Today, at least a dozen firms supply user-friendly laser systems optimized for a range of art-conservation divestment applications. The first-generation laser-cleaning tools are essentially a laser, a beam-delivery device, and a debris- collection accessory. Advanced developmental work has turned in large measure to ancillary subsystems for more sophisticated process control. Of particular importance are acoustic, optical, spectral, EMP, and electronic-vision process control. Beam direction may be via manual, translational-scanner, or robotic beam positioning implemented by means of fiber optics, minors, or prisms and computer control. Substrate thermal alteration and debris redeposition may be minimized or avoided through the incorporation of a gas jet, fluid or fluid jet, or dry-ice blast.

  13. Laser Safety Inspection Criteria

    SciTech Connect

    Barat, K

    2005-06-13

    A responsibility of the Laser Safety Officer (LSO) is to perform laser audits. The American National Standard Z136.1 Safe Use of Lasers references this requirement through several sections. One such reference is Section 1.3.2.8, Safety Features Audits, ''The LSO shall ensure that the safety features of the laser installation facilities and laser equipment are audited periodically to assure proper operation''. The composition, frequency and rigor of that inspection/audit rests in the hands of the LSO. A common practice for institutions is to develop laser audit checklists or survey forms It is common for audit findings from one inspector or inspection to the next to vary even when reviewing the same material. How often has one heard a comment, ''well this area has been inspected several times over the years and no one ever said this or that was a problem before''. A great number of audit items, and therefore findings, are subjective because they are based on the experience and interest of the auditor to particular items on the checklist. Beam block usage, to one set of eyes might be completely adequate, while to another, inadequate. In order to provide consistency, the Laser Safety Office of the National Ignition Facility Directorate has established criteria for a number of items found on the typical laser safety audit form. The criteria are distributed to laser users. It serves two broad purposes; first, it gives the user an expectation of what will be reviewed by an auditor. Second, it is an opportunity to explain audit items to the laser user and thus the reasons for some of these items, such as labelling of beam blocks.

  14. Laser diode array pumped continuous wave Rubidium vapor laser.

    PubMed

    Zhdanov, B V; Stooke, A; Boyadjian, G; Voci, A; Knize, R J

    2008-01-21

    We have demonstrated continuous wave operation of a laser diode array pumped Rb laser with an output power of 8 Watts. A slope efficiency of 60% and a total optical efficiency of 45% were obtained with a pump power of 18 Watts. This laser can be scaled to higher powers by using multiple laser diode arrays or stacks of arrays.

  15. Comparative shock wave analysis during corneal ablation with an excimer laser, picosecond laser, and femtosecond laser

    NASA Astrophysics Data System (ADS)

    Krueger, Ronald R.; Juhasz, Tibor

    1995-05-01

    With the event of topographic steep central islands following excimer laser surgery and the potential damage to the corneal endothelium, shock waves are playing an increasingly important role in laser refractive surgery. With this in mind, we performed a comparative shock wave analysis in corneal tissue using an excimer laser, picosecond laser, and femtosecond laser. We used a Lambda Physik excimer laser at 308 nm wavelength, a Nd:YLF picosecond laser at 1053 nm wavelength and a synchronously pumped linear cavity femtosecond laser at 630 nm wavelength. The pulse widths of the corresponding lasers were 8 ns, 18 ps, 150 fs, respectively. The energy density of irradiation was 2.5 to 8 times the threshold level being 2 J/cm2 (excimer laser), 86 J/cm2 (picosecond laser) and 10.3 J/cm2 (femtosecond laser). Shock wave dynamics were analyzed using time-resolved photography on a nanosecond time scale using the picosecond laser in corneal tissue, water and air. Shock wave dynamics using the femtosecond laser were studied in water only while the excimer laser induced shock wave during corneal ablation was studied in air only. We found the dynamics of shock waves to be similar in water and corneal tissue indicating that water is a good model to investigate shock wave effects in the cornea. The magnitude of the shock wave velocity and pressure decays over time to that of a sound wave. The distance over which it decays is 3 mm in air with the excimer laser and 600 - 700 micrometers in air with the picosecond laser. In water, the picosecond laser shock wave decays over a distance of 150 micrometers compared to the femtosecond laser shock wave which decays over a distance of 30 micrometers . Overall the excimer laser shock wave propagates 5 times further than that of the picosecond laser and the picosecond laser shock wave propagates 5 times further than that of the femtosecond laser. In this preliminary comparison, the time and distance for shock wave decay appears to be directly

  16. Consistency analysis on laser signal in laser guided weapon simulation

    NASA Astrophysics Data System (ADS)

    Yin, Ruiguang; Zhang, Wenpan; Guo, Hao; Gan, Lin

    2015-10-01

    The hardware-in-the-loop simulation is widely used in laser semi-active guidance weapon experiments, the authenticity of the laser guidance signal is the key problem of reliability. In order to evaluate the consistency of the laser guidance signal, this paper analyzes the angle of sight, laser energy density, laser spot size, atmospheric back scattering, sun radiation and SNR by comparing the different working state between actual condition and hardware-in-the-loop simulation. Based on measured data, mathematical simulation and optical simulation result, laser guidance signal effects on laser seeker are determined. By using Monte Carlo method, the laser guided weapon trajectory and impact point distribution are obtained, the influence of the systematic error are analyzed. In conclusion it is pointed out that the difference between simulation system and actual system has little influence in normal guidance, has great effect on laser jamming. The research is helpful to design and evaluation of laser guided weapon simulation.

  17. Frequency stabilization of diode-laser-pumped solid state lasers

    NASA Technical Reports Server (NTRS)

    Byer, Robert L.

    1988-01-01

    The goal of the NASA Sunlite program is to fly two diode-laser-pumped solid-state lasers on the space shuttle and while doing so to perform a measurement of their frequency stability and temporal coherence. These measurements will be made by combining the outputs of the two lasers on an optical radiation detector and spectrally analyzing the beat note. Diode-laser-pumped solid-state lasers have several characteristics that will make them useful in space borne experiments. First, this laser has high electrical efficiency. Second, it is of a technology that enables scaling to higher powers in the future. Third, the laser can be made extremely reliable, which is crucial for many space based applications. Fourth, they are frequency and amplitude stable and have high temporal coherence. Diode-laser-pumped solid-state lasers are inherently efficient. Recent results have shown 59 percent slope efficiency for a diode-laser-pumped solid-state laser. As for reliability, the laser proposed should be capable of continuous operation. This is possible because the diode lasers can be remote from the solid state gain medium by coupling through optical fibers. Diode lasers are constructed with optical detectors for monitoring their output power built into their mounting case. A computer can actively monitor the output of each diode laser. If it sees any variation in the output power that might indicate a problem, the computer can turn off that diode laser and turn on a backup diode laser. As for stability requirements, it is now generally believed that any laser can be stabilized if the laser has a frequency actuator capable of tuning the laser frequency as far as it is likely to drift in a measurement time.

  18. Laser applications in surgery

    PubMed Central

    Azadgoli, Beina

    2016-01-01

    In modern medicine, lasers are increasingly utilized for treatment of a variety of pathologies as interest in less invasive treatment modalities intensifies. The physics behind lasers allows the same basic principles to be applied to a multitude of tissue types using slight modifications of the system. Multiple laser systems have been studied within each field of medicine. The term “laser” was combined with “surgery,” “ablation,” “lithotripsy,” “cancer treatment,” “tumor ablation,” “dermatology,” “skin rejuvenation,” “lipolysis,” “cardiology,” “atrial fibrillation (AF),” and “epilepsy” during separate searches in the PubMed database. Original articles that studied the application of laser energy for these conditions were reviewed and included. A review of laser therapy is presented. Laser energy can be safely and effectively used for lithotripsy, for the treatment of various types of cancer, for a multitude of cosmetic and reconstructive procedures, and for the ablation of abnormal conductive pathways. For each of these conditions, management with lasers is comparable to, and potentially superior to, management with more traditional methods. PMID:28090508

  19. Laser scar revision.

    PubMed

    Lupton, Jason R; Alster, Tina S

    2002-01-01

    A variety of lasers can be used to treat scars and striae effectively. It is of paramount importance that the type of scar be properly classified on initial examination so that the most appropriate method of treatment can be chosen. Classification also allows the laser surgeon to discuss with the patient the anticipated response to treatment. The 585-nm pulsed dye laser (PDL) is the most appropriate system for treating hypertrophic scars, keloids, erythematous scars, and striae. The PDL carries a low risk of side effects and complications when operated at appropriate treatment parameters and time intervals. Atrophic scars are best treated with ablative CO2 and Er:YAG lasers; however, proliferative keloids and hypertrophic scars should not be vaporized because of the high risk of scar recurrence or progression. The appropriate choice and use of lasers can significantly improve most scars. As research in laser-skin interaction continues, further refinements in laser technology coupled with the addition of alternate treatment procedures will allow improved clinical efficacy and predictability.

  20. Fractional laser skin resurfacing.

    PubMed

    Alexiades-Armenakas, Macrene R; Dover, Jeffrey S; Arndt, Kenneth A

    2012-11-01

    Laser skin resurfacing (LSR) has evolved over the past 2 decades from traditional ablative to fractional nonablative and fractional ablative resurfacing. Traditional ablative LSR was highly effective in reducing rhytides, photoaging, and acne scarring but was associated with significant side effects and complications. In contrast, nonablative LSR was very safe but failed to deliver consistent clinical improvement. Fractional LSR has achieved the middle ground; it combined the efficacy of traditional LSR with the safety of nonablative modalities. The first fractional laser was a nonablative erbium-doped yttrium aluminum garnet (Er:YAG) laser that produced microscopic columns of thermal injury in the epidermis and upper dermis. Heralding an entirely new concept of laser energy delivery, it delivered the laser beam in microarrays. It resulted in microscopic columns of treated tissue and intervening areas of untreated skin, which yielded rapid reepithelialization. Fractional delivery was quickly applied to ablative wavelengths such as carbon dioxide, Er:YAG, and yttrium scandium gallium garnet (2,790 nm), providing more significant clinical outcomes. Adjustable laser parameters, including power, pitch, dwell time, and spot density, allowed for precise determination of percent surface area, affected penetration depth, and clinical recovery time and efficacy. Fractional LSR has been a significant advance to the laser field, striking the balance between safety and efficacy.

  1. Laser Ion Acceleration Control

    NASA Astrophysics Data System (ADS)

    Kawata, Shigeo; Nagashima, T.; Izumiyama, T.; Sato, D.; Takano, M.; Barada, D.; Ma, Y. Y.; Gu, Y. J.; Kong, Q.; Wang, P. X.; Wang, W. M.

    2013-10-01

    An intense femtosecond pulsed laser is employed to accelerate ions. The issues in the laser ion accelerator include the energy efficiency from the laser to the ions, the ion beam collimation, the ion energy spectrum control, the ion beam bunching, the ion particle energy control, etc. In the study particle computer simulations were performed to solve the issues, and each component was designed to control the ion beam quality. When an intense laser illuminates a target, electrons in the target are accelerated and leave from the target; temporarily a strong electric field is formed between the high-energy electrons and the target ions, and the target ions are accelerated. The energy efficiency from the laser to ions was improved by using a solid target with a fine sub-wavelength structure or by a near critical density gas plasma. The ion beam collimation was realized by holes behind the solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching were successfully realized by a multi-stage laser-target interaction. The present study proposed a novel concept for a future compact laser ion accelerator, based on each component study required to control the ion beam quality and parameters. Partly supported by JSPS, MEXT, CORE, Japan/US Cooperation program, ASHULA and ILE/Osaka University.

  2. Lasers in digestive endoscopy

    NASA Astrophysics Data System (ADS)

    Brunetaud, Jean Marc; Maunoury, Vincent; Cochelard, Dominique

    1997-01-01

    Lasers were introduced in digestive endoscopy to stop active gastroduodenal hemorrhages. Their use spread progressively to the treatment of chronic hemorrhages from vascular malformations and sessile tumors. Laser face competition from other endoscopic techniques such as electrocoagulation, injection techniques, dilation, stents, and brachytherapy. Many series have reported the efficacy of lasers in digestive endoscopy used for their thermal or photochemical effects. However, they were gradually abandoned for the treatment of hemorrhages because of competition from nonlaser techniques. Lasers are still used for ablation of sessile tumors, but their true impact is difficult to evaluate. Modern methods of technology assessment did not allow gastroenterologists to clearly define the place of lasers among surgery, radio-chemotherapy, and other endoscopic techniques, and data on the daily use of lasers are not available. Therefore, the conclusion can only be subjective. The best current application of thermal lasers appears to be in the treatment of rectosigmoid villous adenomas in elderly patients. Small superficial rectal cancers may also become a good subject due to the impact of endoscopic ultrasonography. Early lesions with multifocal or diffuse disease such as early esophageal cancers could be the most promising subject of application for photodynamic therapy in the future.

  3. Laser Propulsion Standardization Issues

    SciTech Connect

    Scharring, Stefan; Eckel, Hans-Albert; Roeser, Hans-Peter; Sinko, John E.; Sasoh, Akihiro

    2010-10-08

    It is a relevant issue in the research on laser propulsion that experimental results are treated seriously and that meaningful scientific comparison is possible between groups using different equipment and measurement techniques. However, critical aspects of experimental measurements are sparsely addressed in the literature. In addition, few studies so far have the benefit of independent confirmation by other laser propulsion groups. In this paper, we recommend several approaches towards standardization of published laser propulsion experiments. Such standards are particularly important for the measurement of laser ablation pulse energy, laser spot area, imparted impulse or thrust, and mass removal during ablation. Related examples are presented from experiences of an actual scientific cooperation between NU and DLR. On the basis of a given standardization, researchers may better understand and contribute their findings more clearly in the future, and compare those findings confidently with those already published in the laser propulsion literature. Relevant ISO standards are analyzed, and revised formats are recommended for application to laser propulsion studies.

  4. History of lasers.

    PubMed

    Gross, Andreas J; Herrmann, Thomas R W

    2007-06-01

    The developments of laser technology from the cradle of modern physics in 1900 by Planck to its latest medical boundaries is an exciting example of how basic physics finds its way into clinical practice. This article merits the protagonists and their contribution to the steps in this development. The competition between the different research groups finally led to the award of the Nobel Prize to Townes, Basov and Prokhorov in 1964 for the scientific basis on quantum electronics, which led to the construction of oscillators and amplifiers based on the laser-maser principle. Forty-three years after Einstein's first theories Maiman introduced the first ruby laser for commercial use. This marked the key step for the laser application and pioneered fruitful cooperations between basic and clinical science. The pioneers of lasers in clinical urology were Parsons in 1966 with studies in canine bladders and Mulvany 1968 with experiments in calculi fragmentation. The central technological component for the triumphal procession of lasers in urology is the endoscope. Therefore lasers are currently widely used, being the tool of choice in some areas, such as endoscopical lithotriptic stone treatment or endoluminal organ-preserving tumor ablation. Furthermore they show promising treatment alternatives for the treatment of benign prostate hyperplasia.

  5. A borane laser

    NASA Astrophysics Data System (ADS)

    Cerdán, Luis; Braborec, Jakub; Garcia-Moreno, Inmaculada; Costela, Angel; Londesborough, Michael G. S.

    2015-01-01

    Emission from electronically excited species forms the basis for an important class of light sources—lasers. So far, commercially available solution-processed blue-emitting laser materials are based on organic compounds or semiconductor nanocrystals that have significant limitations: either low solubility, low chemical- and/or photo-stability and/or uncompetitive prices. Here we report a novel and competitive alternative to these existing laser materials that is based on boron hydrides, inorganic cluster compounds with a rich and diverse chemistry. We demonstrate that solutions of the borane anti-B18H22 show, under pulsed excitation, blue laser emission at 406 nm with an efficiency (ratio of output/input energies) of 9.5%, and a photostability superior to many of the commercially available state-of-the-art blue laser dyes. This demonstration opens the doors for the development of a whole new class of laser materials based on a previously untapped resource for laser technology—the boranes.

  6. 1982 laser program annual report

    SciTech Connect

    Hendricks, C.D.; Grow, G.R.

    1983-08-01

    This annual report covers the following eight sections: (1) laser program review, (2) laser systems and operation, (3) target design, (4) target fabrication, (5) fusion experiments program, (6) Zeus laser project, (7) laser research and development, and (8) energy applications. (MOW)

  7. Dye laser traveling wave amplifier

    NASA Technical Reports Server (NTRS)

    Davidson, F.

    1983-01-01

    A flash lamp pumped dye laser suitable for use as an amplifier stage was developed. The desired output laser pulses are of nanosecond duration, tunable in center frequency, and of good optical quality. Its usefulness as a laser oscillator is emphasized, because it constitutes a compact, relatively efficient source of tunable dye laser light.

  8. Piezoelectric measurement of laser power

    DOEpatents

    Deason, Vance A.; Johnson, John A.; Telschow, Kenneth L.

    1991-01-01

    A method for measuring the energy of individual laser pulses or a series of laser pulses by reading the output of a piezoelectric (PZ) transducer which has received a known fraction of the total laser pulse beam. An apparatus is disclosed that reduces the incident energy on the PZ transducer by means of a beam splitter placed in the beam of the laser pulses.

  9. Monolithic blue upconversion fiber laser

    NASA Astrophysics Data System (ADS)

    Gaebler, Volker; Eichler, Hans J.

    2002-06-01

    We report a monolithic low threshold 482nm Tm:ZBLAN upconversion fiber laser. The laser cavity consists of a directly coated single-mode fluoride fiber. The vapor deposit coatings significantly reduce the coupling losses and are suitable to be pumped by laser diodes. The laser operation and threshold characteristics have been investigated. The output stability and beam quality was tested.

  10. Analog Simulation of a Laser.

    ERIC Educational Resources Information Center

    Kessler, Gary

    1982-01-01

    Presents an analog simulation of laser properties (finding time evolution of the intensity of a ruby laser pulse) which serves as the basis of a three-four hour laboratory experiment. Includes programs for solution to rate equations of a three-level laser and production of a giant pulse in a ruby laser. (Author/SK)

  11. Ultra-fast laser system

    DOEpatents

    Dantus, Marcos; Lozovoy, Vadim V

    2014-01-21

    A laser system is provided which selectively excites Raman active vibrations in molecules. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and remote sensing.

  12. Color Laser Microscope

    NASA Astrophysics Data System (ADS)

    Awamura, D.; Ode, T.; Yonezawa, M.

    1987-04-01

    A color laser microscope utilizing a new color laser imaging system has been developed for the visual inspection of semiconductors. The light source, produced by three lasers (Red; He-Ne, Green; Ar, Blue; He-Cd), is deflected horizontally by an AOD (Acoustic Optical Deflector) and vertically by a vibration mirror. The laser beam is focused in a small spot which is scanned over the sample at high speed. The light reflected back from the sample is reformed to contain linear information by returning to the original vibration mirror. The linear light is guided to the CCD image sensor where it is converted into a video signal. Individual CCD image sensors are used for each of the three R, G, or B color image signals. The confocal optical system with its laser light source yields a color TV monitor image with no flaring and a much sharper resolution than that of the conventional optical microscope. The AOD makes possible a high speed laser scan and a NTSC or PAL TV video signal is produced in real time without any video memory. Since the light source is composed of R, G, and B laser beams, color separation superior to that of white light illumination is achieved. Because of the photometric linearity of the image detector, the R, G, and B outputs of the system are most suitably used for hue analysis. The CCD linear image sensors in the optical system produce no geometrical distortion, and good color registration is available principally. The output signal can be used for high accuracy line width measuring. The many features of the color laser microscope make it ideally suited for the visual inspection of semiconductor processing. A number of these systems have already been installed in such a capacity. The Color Laser Microscope can also be a very useful tool for the fields of material engineering and biotechnology.

  13. [Ablative and fractional lasers].

    PubMed

    Beylot, C; Grognard, C; Michaud, T

    2009-10-01

    The use of pulsed or scanning Carbon Dioxide, and pulsed Erbium-YAG lasers allows the programmable and reproducible photocoagulation of thin layers of the epidermis and superficial dermis. Thermal damage depends on the type of laser and is greater with CO(2) lasers. The degree of neocollagenesis is proportional to the thermal damage and is better with CO(2) lasers. Their main indication is the correction of photoaged facial skin but they can also be used for corrective dermatology, e.g. for scars and genodermatosis. Results are highly satisfactory but the technique is invasive and the patient experiences a social hindrance of around two weeks. Fractionated techniques treat 25% of the defective skin area at each session in noncontiguous microzones; four sessions are therefore necessary to treat the entire cutaneous surface. The treatment is given under topical anesthesia and is much less invasive, particularly with nonablative fractional laser treatment in which photothermolysis does not penetrate below the epidermis and/or the effects are slight, with no or very little social isolation. However, the results are much less satisfactory than the results of ablative laser and there is no firming effect. Other zones than the face can be treated. With the fractional CO(2) and Erbium ablative lasers, which have multiplied over the past 2 years, the much wider impacts cause perforation of the epidermis and there is a zone of ablation by laser photovaporization, with a zone of thermal damage below. The results are better in correcting photoaging of the face, without, however, achieving the efficacy of ablative lasers, which remain the reference technique. However, the effects are not insignificant, requiring at least 5 days of social isolation.

  14. Laser treatment for skin disease

    NASA Astrophysics Data System (ADS)

    Bloznelyte-Plesniene, Laima; Cepulis, Vytautas; Ponomarev, Igor V.

    1996-12-01

    The correct selection of patients is the most difficult part of the laser treatment. Since 1985 the total number of patients treated by us using different laser systems was 1544. High power lasers: Nd:YAG and CO2 lasers were used by us for surgical treatment. Low power lasers: Helium-Neon, Copper vapor, gold vapor and dye lasers were applied by us to PDT or to treatment of port wine hemangiomas. this paper reports our efforts in selecting the patients with different skin lesions for the treatment with different laser systems.

  15. Tunable random fiber laser

    SciTech Connect

    Babin, S. A.; Podivilov, E. V.; El-Taher, A. E.; Harper, P.; Turitsyn, S. K.

    2011-08-15

    An optical fiber is treated as a natural one-dimensional random system where lasing is possible due to a combination of Rayleigh scattering by refractive index inhomogeneities and distributed amplification through the Raman effect. We present such a random fiber laser that is tunable over a broad wavelength range with uniquely flat output power and high efficiency, which outperforms traditional lasers of the same category. Outstanding characteristics defined by deep underlying physics and the simplicity of the scheme make the demonstrated laser a very attractive light source both for fundamental science and practical applications.

  16. Ring laser gyroscope anode

    SciTech Connect

    Ljung, B.H.

    1981-03-17

    An anode for a ring laser gyroscope which provides improved current stability in the glow discharge path is disclosed. The anode of this invention permits operation at lower currents thereby allowing a reduction of heat dissipation in the ring laser gyroscope. The anode of one embodiment of this invention is characterized by a thumbtack appearance with a spherical end where the normal sharp end of the thumbtack would be located. The stem of the anode extends from the outside of the gyroscope structure to the interior of the structure such that the spherical end is substantially adjacent to the laser beam.

  17. Lasers In Dental Diagnosis

    NASA Astrophysics Data System (ADS)

    Everse, K. E.; Sinor, T. W.; Menzel, E. R.

    1987-01-01

    We have investigated the potential of lasers for real time in situ dental diagnosis via transillumination of teeth and gums and via fluorescence. Not surprisingly, absorption and/or scattering of light by teeth was found to be insensitive to light color. However, monochromatic transillumination revealed detail better than white light. Transillumination of gums was best performed with orange-red light because of tissue absorption. Illumination of oral structures by 488 nm Ar-laser light was effective in revealing diagnosis detail by fluorescence. Incipient caries and fine tooth fracture lines that are generally not revealed by radiography were observable by laser.

  18. Laser Spectroscopy of Plasmas.

    DTIC Science & Technology

    1987-03-15

    AD-F161 00? LASER SPECTROSCOPY OF PLASMASMU CALIFORNIA NIY 1/1 BEKEEY J N DAILY 15 MAR 6? AFOSit-TR-6?-9?44 AFOSi-OS-0E? UNL SIFIF Z F//G2/9 M 22.5...TITLE (Inluded Secuity Clusifeation) 61102F 2308 I A3 Laser Spectroscopy of Plasmas ____________ % 12. PERSONAL AUTHOR(hI John W. Daily 13.. TYPE OF...Con Eanue on everse if neceuary and idenety by bioc* numInboen During the past year, work was initiated to develop novel advanced laser spectroscopy

  19. Photodynamic therapy laser system

    NASA Astrophysics Data System (ADS)

    Shu, Xiaoqin; Lin, Qing; Wang, Feng; Shu, Chao; Wang, Jianhua

    2009-08-01

    Photodynamic therapy (PDT) treatment is a new treatment for tumour and Dermatology. With the successful development of the second-generation photosensitizer and the significant manifestations in clinics, PDT has shown a more extensive application potentials. To activate the photosensitizer, in this paper, we present a GaAs-based diode laser system with a wavelength of 635 nm. In this system, to prolong the working life-time of the diode lasers, we use specific feedback algorithm to control the current and the temperature of the diode laser with high precision. The clinic results show an excellent effect in the treatment of Condyloma combined with 5-ALA.

  20. Applications of Laser Diagnostics

    DTIC Science & Technology

    2005-03-01

    sonics Phantom v5.0 Photron FASTCAM- Ultima SE 1 6 PDE Exhaust Exhaust Flow from High-Speed Camera (18,000 fps) Image from Conventional Video Camera...employing DCM laser dye) with a second frequency-doubled, Q-switched Nd:YAG laser; this results in laser radiation at 640 nm (40 mJ/pulse at the...digital imaging at rates up to 62,500 frames-per-second (fps) is employed using a Phantom v5.0 CMOS-based digital camera. At this framing rate, it

  1. Pulsed Laser Propulsion.

    DTIC Science & Technology

    1978-10-01

    Journal, Vol. 12, No. 9,September 1974, pp. 1254-1261. 5. D. D. Papailiou, ed., "Frontiers in Propulsion Research: Laser, Matter - Antimatter , Exited...82177AD-AI09 850 PHYSICAL SCIENCES INC WOBURN MA F/G 20/5 PULSED LASER PROPULSION .(U) OCT 78 P E NEBOLSINE, A N PIRRI, J S GOELA N00014-76-C 0738...UNCLASSIFIED PSI-TR-142 III~~D EEC~h~I -M 0 1111_L251.4 11 [4 LEVEL2PSI TR-1 2 LO "r PULSED LASER PROPULSION " P. E. Nebolsine, A. N. Pirri, J. S. Goela, G

  2. Submarine laser communications

    NASA Astrophysics Data System (ADS)

    McConathy, D. R.

    The Department of the Navy and the Defense Advanced Research Projects Agency (DARPA) are sponsoring a joint study to investigate the use of blue-green laser technology to comunicate with submarines at operating depths. Two approaches are under investigation - one in which the laser itself is space-based, and the other in which the laser is ground-based with its beam redirected to the earth's surface by an orbiting mirror. This paper discusses these two approaches, and presents a brief history of activities which led to the current studies.

  3. Thallium Mercury Laser Development.

    DTIC Science & Technology

    1980-04-17

    AD-A9 840 WESTINGHOUSE RESEARCH AND DEVELOPMENT CENTER PITTSBU--ETC F/A 20/5 THALLIUM MERCURY LASER DEVELOPMENT .(U) APR 80 C S LIU, D W FELDMAN, J L...PACK NO001I78-C-0131 lIlrt A nEQE-WOTFX-R NL THALLIUM MERCURY LASER DEVELOPMENT C. S. Liu, D. W. Feldman and J. L. Pack FINAL REPORT (PHASE II...PERIOD COVERED Thallium Mercury Laser Development -T- Final Report (Phase II) Feb. 1, 1979 to Jan. 31, 1980 77a. w-atF. -REPORT NUMBER _,___C2-OTEX

  4. Fiber optic laser rod

    DOEpatents

    Erickson, G.F.

    1988-04-13

    A laser rod is formed from a plurality of optical fibers, each forming an individual laser. Synchronization of the individual fiber lasers is obtained by evanescent wave coupling between adjacent optical fiber cores. The fiber cores are dye-doped and spaced at a distance appropriate for evanescent wave coupling at the wavelength of the selected dye. An interstitial material having an index of refraction lower than that of the fiber core provides the optical isolation for effective lasing action while maintaining the cores at the appropriate coupling distance. 2 figs.

  5. Multiaxis laser eigenstates

    SciTech Connect

    Brunel, M.; Le Floch, A.; Bretenaker, F.

    1996-05-01

    We derive a theoretical model based on a generalized Jones matrix formalism to calculate the eigenstates of lasers with {ital N} propagation axes. Spatial separation of the beams is realized inside the cavity by a collection of double-refraction crystals. This method allows one to adapt the mode volume to the geometry of the active medium. {ital N}-forked eigenstates are isolated, and the possibility of scaling up the TEM{sub 00} output power of a monomode laser is shown. All these features are tested experimentally in two-, four-, and eight-axis lasers and show good agreement with the theoretical predictions. {copyright} {ital 1996 Optical Society of America.}

  6. Diatomic gasdynamic lasers.

    NASA Technical Reports Server (NTRS)

    Mckenzie, R. L.

    1972-01-01

    Predictions from a numerical model of the vibrational relaxation of anharmonic diatomic oscillators in supersonic expansions are used to show the extent to which the small anharmonicity of gases like CO can cause significant overpopulations of upper vibrational states. When mixtures of CO and N2 are considered, radiative gain on many of the vibration-rotation transitions of CO is predicted. Experiments are described that qualitatively verify the predictions by demonstrating laser oscillation in CO-N2 expansions. The resulting CO-N2 gasdynamic laser displays performance characteristics that equal or exceed those of similar CO2 lasers.

  7. Diatomic gasdynamic lasers

    NASA Technical Reports Server (NTRS)

    Mckenzie, R. L.

    1971-01-01

    Predictions from a numerical model of the vibrational relaxation of anharmonic diatomic oscillators in supersonic expansions are used to show the extent to which the small anharmonicity of gases like CO can cause significant overpopulations of upper vibrational states. When mixtures of CO and N2 are considered, radiative gain on many of the vibration-rotation transitions of CO is predicted. Experiments are described that qualitatively verify the predictions by demonstrating laser oscillation in CO-N2 expansions. The resulting CO-N2 gasdynamic laser displays performance characteristics that equal or exceed those of similar CO2 lasers.

  8. Supersonic laser propulsion.

    PubMed

    Rezunkov, Yurii; Schmidt, Alexander

    2014-11-01

    To produce supersonic laser propulsion, a new technique based on the interaction of a laser-ablated jet with supersonic gas flow in a nozzle is proposed. It is shown that such parameters of the jet, such as gas-plasma pressure and temperature in the ablation region as well as the mass consumption rate of the ablated solid propellant, are characteristic in this respect. The results of numerical simulations of the supersonic laser propulsion are presented for two types of nozzle configuration. The feasibility to achieve the momentum coupling coefficient of C(m)∼10(-3) N/W is shown.

  9. Optimising Laser Tattoo Removal

    PubMed Central

    Sardana, Kabir; Ranjan, Rashmi; Ghunawat, Sneha

    2015-01-01

    Lasers are the standard modality for tattoo removal. Though there are various factors that determine the results, we have divided them into three logical headings, laser dependant factors such as type of laser and beam modifications, tattoo dependent factors like size and depth, colour of pigment and lastly host dependent factors, which includes primarily the presence of a robust immune response. Modifications in the existing techniques may help in better clinical outcome with minimal risk of complications. This article provides an insight into some of these techniques along with a detailed account of the factors involved in tattoo removal. PMID:25949018

  10. Optimising laser tattoo removal.

    PubMed

    Sardana, Kabir; Ranjan, Rashmi; Ghunawat, Sneha

    2015-01-01

    Lasers are the standard modality for tattoo removal. Though there are various factors that determine the results, we have divided them into three logical headings, laser dependant factors such as type of laser and beam modifications, tattoo dependent factors like size and depth, colour of pigment and lastly host dependent factors, which includes primarily the presence of a robust immune response. Modifications in the existing techniques may help in better clinical outcome with minimal risk of complications. This article provides an insight into some of these techniques along with a detailed account of the factors involved in tattoo removal.

  11. Color speckle in laser displays

    NASA Astrophysics Data System (ADS)

    Kuroda, Kazuo

    2015-07-01

    At the beginning of this century, lighting technology has been shifted from discharge lamps, fluorescent lamps and electric bulbs to solid-state lighting. Current solid-state lighting is based on the light emitting diodes (LED) technology, but the laser lighting technology is developing rapidly, such as, laser cinema projectors, laser TVs, laser head-up displays, laser head mounted displays, and laser headlamps for motor vehicles. One of the main issues of laser displays is the reduction of speckle noise1). For the monochromatic laser light, speckle is random interference pattern on the image plane (retina for human observer). For laser displays, RGB (red-green-blue) lasers form speckle patterns independently, which results in random distribution of chromaticity, called color speckle2).

  12. Wound healing after laser surgery.

    PubMed

    Hendrick, D A; Meyers, A

    1995-10-01

    Compared with scalpel wounds, CO2 laser wounds show delays in inflammation, collagen production, reepithelialization, and tensile strength in the early stages of healing. Some of these delays are similar to those seen with electrocautery and burn wounds. Later stages compensate for these early deficiencies, because scalpel and laser wounds become more similar in epithelialization and wound strength over time. Healed CO2 laser wounds tend to have less scar contraction than scalpel wounds. Débridement of initial laser wound char, tissue cooling techniques during lasering, and pulsed modes of laser delivery all seem to result in more rapid, favorable healing. Similar wound healing trends have been seen with the CO2 laser in bone, with other lasers, and with laser vascular and neural anastomosis. Biostimulation with low-level laser energy is a complex subject of ongoing investigations.

  13. Pulsed laser beam intensity monitor

    SciTech Connect

    Cason, C.M.; Jones, R.W.

    1982-07-13

    A pulsed laser beam intensity monitor measures the peak power within a selectable cross section of a test laser beam and measures integrated energy of the beam during the pulse period of a test laser. A continuous wave laser and a pulsed ruby laser are coaxially arranged for simultaneously transmitting optical output energy through a crystal flat during the time a test laser pulse is transmitted through the flat. Due to stress birefringence in the crystal, the ruby laser pulse transmitted through the flat is recorded and analyzed to provide peak power information about the test laser output pulse, and the continuous wave laser output reflected from the crystal flat provides a measurement of energy during the test laser pulse.

  14. Laser applications in neurosurgery

    NASA Astrophysics Data System (ADS)

    Cerullo, Leonard J.

    1985-09-01

    The "false start" of the laser in neurosurgery should not be misconstrued as a denial of the inherent advantages of precision and gentleness in dealing with neural tissue. Rather, early investigators were frustrated by unrealistic expectations, cumbersome equipment, and a general ignorance of microtechnique. By the early 70s, microneurosurgery was well established, surgical laser equipment for free hand and microlinked application had been developed, and a more realistic view of the limitations of the laser had been established. Consequently, the late 70s really heralded the renaissance of the laser in neurosurgery. Since then, there has been an overwhelming acceptance of the tool in a variety of clinical situations, broadly categorized in five groups. 1)|Perhaps the most generally accepted area is in the removal of extra-axial tumors of the brain and spinal cord. These tumors, benign by histology but treacherous by location, do not present until a significant amount of neurological compensation has already occurred. The application of additional trauma to the neural tissue, whether by further tumor growth or surgical manipulation, frequently results in irreversible damage. Here, the ability of the laser to vaporize tissue, in a fairly hemostatic fashion, without mechanical or thermal damage to sensitive surrounding tissues, is essential. 2)|The ability to incise delicate neural tissue with minimal spread of thermal destruction to adjacent functioning tissue makes the laser the ideal instrument when tumors deep under the surface are encountered in the brain or spinal cord. Thus, the second group of applications is in the transgression of normal neural structures to arrive at deeper pathological tissue. 3)|The third area of benefit for the laser in neurosurgery has been in the performance of neuroablative procedures, calling for deliberate destruction of functioning neural tissue in a controlled fashion. Again, the precision and shape confinement of the destructive

  15. 21 CFR 1040.10 - Laser products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... electronic product, provided that such laser product: (i) Is accompanied by a general warning notice that... section and § 1040.11 for complete laser products, and (iii) Is not a removable laser system as described... intended to incorporate a laser or laser system. A laser or laser system that is intended for use as......

  16. Positronium Annihilation Gamma Ray Laser

    DTIC Science & Technology

    2009-07-01

    laser was done for both high power and good mode. Alexandrite laser, PAL 101 A custom made Alexandrite laser was purchased from Lightage. Work...Calibration for the Alexandrite laser is being verified and other behavioral aspects are currently explored and measured. Optics Four beamsplitters, CVI...safely. The 1.0m and 0.5 meter spectrometer can be used simultaneously with the Alexandrite laser and room is available in front of the Alexandrite

  17. Laser Guide Star Operational Issues

    NASA Astrophysics Data System (ADS)

    Max, C. E.

    Introduction Operational Implications for the Laser System Rayleigh Scattering Focus Changes Variations in Sodium Column Density Requirement to Nod the Telescope for Infra-Red Observing Calibration of the Adaptive Optics System for Sodium Laser Guide - Star Operation Types of Internal Calibration Sources Static Calibration Auxiliary Wavefront Sensors Dynamic Calibration (Real-Time Point-Spread-Function Measurements) Safety Considerations Regarding Laser Guide Star Systems Laser Eye Safety Fire Safety Aircraft Avoidance Spacecraft Damage Avoidance Laser Coordination on Multi-Telescope Summits Conclusions

  18. Combustion diagnostics by laser spectrometry

    NASA Astrophysics Data System (ADS)

    Kitagawa, Kuniyuki; Morita, Shigeaki; Kodama, Kenji; Matsumoto, Kozo

    2009-03-01

    We have developed three different types of visualization methods for energy conversion systems by means of laser spectrometry. (1) Laser-induced fluorescence (LIF) spectroscopy and (2) laser ionization mass spectrometry (LIMS) have been applied to visualization of chemical species in combustion fields of flames. (3) Near-infrared laser absorption spectroscopy has been used for visualization of water in a polymer electrolyte fuel cell (PEFC). Complex physicochemical processes in the energy conversion systems have been revealed by laser spectrometry.

  19. Intravitreal Topotecan Inhibits Laser-induced Choroidal Neovascularization in a Rat Model

    PubMed Central

    Gholipour, Mohammad Ali; Kanavi, Mozhgan Rezaei; Ahmadieh, Hamid; Aldavood, Seyed Javid; Nourinia, Ramin; Hosseini, Seyed Bagher; Daftarian, Narsis; Nashtaei, Ebrahim Mohammad; Tousi, Adib; Safi, Sare

    2015-01-01

    Purpose: A two-phase preclinical study was designed to determine the safe dose of intravitreal topotecan and its inhibitory effect on experimental choroidal neovascularization (CNV) in a rat model. Methods: In phase I, 42 rats were categorized into 6 groups, 5 of which received intravitreal topotecan injections of 0.125 μg, 0.25 μg, 0.5 μg, 0.75 μg, and 1.0 μg/5 μl, respectively; the control group received an injection of normal saline. Ophthalmic examination and electroretinography (ERG) were performed on days 7 and 28, and enucleated globes were processed for histopathology and immunostaining for glial fibrillary acidic protein. In phase II, CNV was induced via laser burns in 20 rats and the animals were divided into 2 groups. One group received topotecan and the other received normal saline intravitreally. Four weeks later, mean scores of fluorescein leakage on fluorescein angiography as well as mean CNV areas on histology sections were compared. Results: In phase I, clinical, ERG and histopathologic results were unremarkable in terms of retinal toxicity in all groups. Based on the results of phase I, a dose of 1 μg/5 μl topotecan was chosen for phase II. Leakage scores obtained from late-phase fluorescein angiography were significantly lower in topotecan-treated than control eyes (P < 0.01) four weeks after induction of CNV. Compared to control eyes, topotecan-treated eyes showed a significantly lower incidence of fibrovascular proliferation (8.7% vs. 96.2%) and significantly smaller areas of CNV (P < 0.01). Conclusion: Intravitreal injection of topotecan at a dose of 1 μg/5 μl is safe and may be a promising treatment for CNV. PMID:26730316

  20. Beamlet laser diagnostics

    SciTech Connect

    Burkhart, S.C.; Behrendt, W.C.; Smith, I.

    1996-06-01

    Beamlet is instrumented extensively to monitor the performance of the overall laser system and many of its subsystems. Beam diagnostics, installed in key locations, are used to fully characterize the beam during its propagation through the multipass cavity and the laser`s output section. This article describes the diagnostics stations located on Beamlet and discusses the design, calibration, and performance of the Beamlet calorimeters. The authors used Nova`s diagnostics packages to develop the Beamlet design to determine beam energy, spatial profile, temporal profile, and other beam parameters. Technologic improvements within the last several years in controls, charge-coupled device (CCD) cameras, and fast oscilloscopes have allowed the authors to obtain more accurate measurements on the Beamlet laser system. They briefly cover some of these techniques, including a description of their LabVIEW based data acquisition system.

  1. Laser cutting nozzle

    DOEpatents

    Ramos, Terry J.

    1984-01-01

    A laser cutting nozzle for use with a laser cutting apparatus directing a focused beam to a spot on a work piece. The nozzle has a cylindrical body with a conical tip which together have a conically shaped hollow interior with the apex at a small aperture through the tip. The conical hollow interior is shaped to match the profile of the laser beam, at full beamwidth, which passes through the nozzle to the work piece. A plurality of gas inlet holes extend through the body to the hollow interior and are oriented to produce a swirling flow of gas coaxially through the nozzle and out the aperture, aligned with the laser beam, to the work piece. BACKGROUND OF THE INVENTION

  2. Laser cutting nozzle

    DOEpatents

    Ramos, T.J.

    1982-09-30

    A laser cutting nozzle for use with a laser cutting apparatus directing a focused beam to a spot on a work piece. The nozzle has a cylindrical body with a conical tip which together have a conically shaped hollow interior with the apex at a small aperture through the tip. The conical hollow interior is shaped to match the profile of the laser beam, at full beamwidth, which passes through the nozzle to the work piece. A plurality of gas inlet holes extend through the body to the hollow interior and are oriented to produce a swirling flow of gas coaxially through the nozzle and out the aperture, aligned with the laser beam, to the work piece.

  3. Laser energy conversion

    NASA Technical Reports Server (NTRS)

    Billman, K. W.

    1975-01-01

    Laser radiation could possibly provide a feasible approach for the transmission of energy between stations and vehicles in space and on earth. The transmitted energy could be used for the operational requirements of the receiving space station, lunar base, or spacecraft. In addition, laser energy could also be employed to provide power for the propulsion of vehicles in space. The present status of development regarding the various technological areas involved in an implementation of these objectives is examined, taking into account the possibility of further advances needed to satisfy the technical requirements. Attention is given to laser-induced chemistry for converting the radiation energy into chemical energy. Other subjects considered are related to photovoltaics, optical diodes, thermo-electronics, laser rockets, and photon engines.

  4. X-Ray Lasers

    ERIC Educational Resources Information Center

    Chapline, George; Wood, Lowell

    1975-01-01

    Outlines the prospects of generating coherent x rays using high-power lasers and indentifies problem areas in their development. Indicates possible applications for coherent x rays in the fields of chemistry, biology, and crystallography. (GS)

  5. Contaminant Monitor Laser

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Under a Small Business Innovation Research contract from Langley Research Center, OPOTEK, Inc. developed a laser transmitter for remote sensing of water vapor in the upper atmosphere. As a leader in developing and using Differential Absorption Lidar, a remote sensing technique to monitor ozone and water vapor in the atmosphere, NASA was interested in upgrading the capabilities of its airborn laser systems. The laser transmitter developed for NASA was used for measuring water vapor in the infrared region. By broadening this concept to other wavelengths, OPOTEK believes a range of industrial applications can be met. In addition, the tunable laser system can be used by the Drug Enforcement Administration to discern the by-products from illegal drug manufacturing. A host of other government, university, and industrial laboratory uses for the technology are also being examined as follow-up by the company.

  6. Paint removal using lasers.

    PubMed

    Liu, K; Garmire, E

    1995-07-20

    Experiments to investigate the potential for practical laser graffiti-removal systems are reported. A universal engineering curve for the time needed for removal of paint from nonconductive substrates that was valid over a range of 10(7) in intensity was measured with a variety of lasers. Comparable times were measured for conductive substrates, when pulses shorter than the thermal conduction times were used. Analysis suggests that Q-switched Nd:YAG lasers may be the most efficient means for removing graffiti and other unwanted paint. An 1-m(2) area of paint 14 µm thick can be removed in approximately 10 min with a 50-Hz laser system of 15-W average power.

  7. Paint removal using lasers

    NASA Astrophysics Data System (ADS)

    Liu, Katherine; Garmire, Elsa

    1995-07-01

    Experiments to investigate the potential for practical laser graffiti-removal systems are reported. A universal engineering curve for the time needed for removal of paint from nonconductive substrates that was valid over a range of 107 in intensity was measured with a variety of lasers. Comparable times were measured for conductive substrates, when pulses shorter than the thermal conduction times were used. Analysis suggests that Q-switched Nd:YAG lasers may be the most efficient means for removing graffiti and other unwanted paint. An 1-m2 area of paint 14 mu m thick can be removed in approximately 10 min with a 50-Hz laser system of 15-W average power.

  8. Laser and Surgery

    NASA Astrophysics Data System (ADS)

    Casaccia, Mario; Campisi, C.; Pasero, E.; Ieracitano, V. M.; Berardi, L.; Padula, P.; Cordaro, S.; Boccardo, F.

    1990-09-01

    Surgeon's hand, guiding a light ray, Laser, instead of holding a common lancet, for dissecting delicately tissues with simultaneous haemostasis on small vessels, represents one of the most interesting expressions of modern technology applied to surgery. The use of Laser in surgery dates back to 25 years ago. Its medical applications, however, are a little more recent. The word Laser comes from "Light Amplification by Stimulated Emission of Radiation". It " is known that any material, which has been stimulated, emits energy of excitation through the so called spontaneous Energy. This means irradiation of "quanta" of electro-magnetic energy untidily in space and time (so called "incoherent Emission"). A Laser source, conversely, emits "coherent" electro-magnetic radiations (so called "stimulated Emission") , whose characteristics consist in: monochromaticity,directional ity, coherence and brilliance.

  9. Laser-heated thruster

    NASA Technical Reports Server (NTRS)

    Kemp, N. H.; Lewis, P. F.

    1980-01-01

    The development of a computer program for the design of the thrust chamber for a CW laser heated thruster was examined. Hydrodgen was employed as the propellant gas and high temperature absorber. The laser absorption coefficient of the mixture/laser radiation combination is given in temperature and species densities. Radiative and absorptive properties are given to determine radiation from such gas mixtures. A computer code for calculating the axisymmetric channel flow of a gas mixture in chemical equilibrium, and laser energy absorption and convective and radiative heating is described. It is concluded that: (1) small amounts of cesium seed substantially increase the absorption coefficient of hydrogen; (2) cesium is a strong radiator and contributes greatly to radiation of cesium seeded hydrogen; (3) water vapor is a poor absorber; and (4) for 5.3mcm radiation, both H2O/CO and NO/CO seeded hydrogen mixtures are good absorbers.

  10. Making Laser Beams Visible.

    ERIC Educational Resources Information Center

    Knotts, Michael

    1993-01-01

    Describes an inexpensive fog machine that is useful for photography and laser demonstrations. The apparatus uses liquid nitrogen to chill steam to make a fine mist safe for precision optics. The device can be made for around $50. (MVL)

  11. LASIK - Laser Eye Surgery

    MedlinePlus

    ... Plastic Surgery Center Laser Surgery Education Center Redmond Ethics Center Global Ophthalmology Guide Academy Publications EyeNet Ophthalmology Information for: International Ophthalmologists Media Medical Students Patients and Public Technicians and Nurses ...

  12. Laser therapy for periodontitis

    NASA Astrophysics Data System (ADS)

    Efanov, O. I.

    2001-04-01

    An investigation was made of applying pulsed (lambda) equals 0.89 micrometers laser radiation in the treatment for early diagnosed periodontitis. The investigation was made on 65 patients (47 patients constituted the experimental group and 18 patients constituted a control group) affected by periodontitis. Clinical and functional tests revealed that laser therapy produced a string effect on the course of the illness. It reduced bleeding, inflammation, and pruritus. However, it did not produce an affect on electroexcitation. Biomicroscopic examinations and periodontium rheography revealed that the gingival blood flow became normal after the course of laser therapy. The capillary permeability and venous congestion decreased, which was confirmed by the increased time of vacuum tests, raised gingival temperature, reduced tissue clearance, and increased oxygen tension. Apart from that, laser therapy subsided fibrinolysis, proteolytic tissue activity, and decreased the exudative inflammation of periodontium.

  13. Petawatt laser absorption bounded

    PubMed Central

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-01-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials. PMID:24938656

  14. Laser-induced bioluminescence

    SciTech Connect

    Hickman, G.D.; Lynch, R.V. III

    1981-01-01

    A project has been initiated to determine the feasibility of developing a complete airborne remote sensing system for rapidly mapping high concentration patches of bioluminescent organisms in the world's oceans. Conceptually, this system would be composed of a laser illuminator to induce bioluminescence and a low light level image intensifier for detection of light. Initial laboratory measurements consisted of using a 2-J flash lamp pulsed optical dye laser to excite bioluminescence in the marine dinoflagellate Pyrocustis lunula at ambient temperature using Rhodamine 6G as the lasing dye (585 nm) and a laser pulse width of 1 microsec. After a latency period of 15-20 msec, the bioluminescence maximum occurred in the blue (480 nm is the wavelength maximum for most dinoflagellate bioluminescence) with the peaking occurring approximately 65 msec after the laser pulse. Planned experiments will investigate the effect of different excitation wavelengths and energies at various temperatures and salinities of the cultures.

  15. Lasers in aesthetic dentistry.

    PubMed

    Adams, Timothy C; Pang, Peter K

    2004-10-01

    This article focuses on lasers and aesthetic dentistry and their unique parallel in history from their early development to their present day usage and application. The demand for aesthetic dentistry has had a major impact not only on treatment planning but also on the choice of materials, techniques, and equipment. It is this demand that has married the use of lasers with aesthetic dentistry. A short literature review on the five basic laser types precedes the basic premise of smile design and its critical importance in attaining the desirable aesthetic end result. A short review on biologic width and biologic zone reinforces their importance when manipulating gingival tissue. Four case reports highlight the use of diode, erbium, and carbon dioxide lasers. The end results show the power of proper treatment planning and the use of a smile design guide when using these instruments and confirm a conservative, aesthetic treatment without compromising the health and function of the patients.

  16. Laser dye technology

    SciTech Connect

    Hammond, P R

    1999-09-01

    The author has worked with laser dyes for a number of years. A first interest was in the Navy blue-green program where a flashlamp pumped dye laser was used as an underwater communication and detection device. It made use of the optical window of sea-water--blue for deep ocean, green for coastal water. A major activity however has been with the Atomic Vapor Laser Isotope Separation Program (AVLIS) at the Lawrence Livermore National Laboratory. The aim here has been enriching isotopes for the nuclear fuel cycle. The tunability of the dye laser is utilized to selectively excite one isotope in uranium vapor, and this isotope is collected electrostatically as shown in Figure 1. The interests in the AVLIS program have been in the near ultra-violet, violet, red and deep-red.

  17. Pulsed inductive HF laser

    NASA Astrophysics Data System (ADS)

    Razhev, A. M.; Churkin, D. S.; Kargapol'tsev, E. S.; Demchuk, S. V.

    2016-03-01

    We report the results of experimentally investigated dependences of temporal, spectral and spatial characteristics of an inductive HF-laser generation on the pump conditions. Gas mixtures H2 - F2(NF3 or SF66) and He(Ne) - H2 - F2(NF3 or SF6) were used as active media. The FWHM pulse duration reached 0.42 μs. This value corresponded to a pulsed power of 45 kW. For the first time, the emission spectrum of an inductive HF laser was investigated, which consisted of seven groups of bands with centres around the wavelengths of 2732, 2736, 2739, 2835, 2837, 2893 and 2913 nm. The cross section profile of the laser beam was a ring with a diameter of about 20 mm and width of about 5 mm. Parameters of laser operation in the repetitively pulsed regime were sufficiently stable. The amplitude instability of light pulses was no greater than 5% - 6%.

  18. Fusion reactor pumped laser

    DOEpatents

    Jassby, D.L.

    1987-09-04

    A nuclear pumped laser capable of producing long pulses of very high power laser radiation is provided. A toroidal fusion reactor provides energetic neutrons which are slowed down by a moderator. The moderated neutrons are converted to energetic particles capable of pumping a lasing medium. The lasing medium is housed in an annular cell surrounding the reactor. The cell includes an annular reflecting mirror at the bottom and an annular output window at the top. A neutron reflector is disposed around the cell to reflect escaping neutrons back into the cell. The laser radiation from the annular window is focused onto a beam compactor which generates a single coherent output laser beam. 10 figs.

  19. The Townes Laser Institute

    NASA Astrophysics Data System (ADS)

    Richardson, Martin

    2009-06-01

    The State of Florida has recently established a new center of excellence in advanced core laser technologies, associated with the College of Optics & Photonics. This center, dedicated in 2007 in tribute to the pioneering work of Charles Townes, whose insight lead to the development of the maser and the laser, will invest in next generation laser technologies for applications to medicine, advanced manufacturing and defense. It joins the cluster of photonics-related centers at UCF, adding a focused national center for the education and training of scientists and engineers in laser technology. This paper describes the mission and objectives of the Townes Institute, the educational and training programs it is creating, its current investments and opportunities, and the future institutional and industrial partnerships and global reach it hopes to create.

  20. Laser Industry Looks At Laser Medicine And Surgery

    NASA Astrophysics Data System (ADS)

    Brunner, Thomas M.

    1982-12-01

    Lasers have come a long way since the old joke that a laser was a solution searching for a problem. Today lasers pervade all aspects of our lives. There are laser light shows at discos, lasers used medically to preserve vision, lasers used to separate cells to detect potential birth defects, lasers used to weld floor-pans for automobiles and laser drilled cigarette filters. There are military applications from laser guided bombs to proposed earth-based lasers with synchronous mirrors on satellites that bring destruction at the speed of light anywhere in the world. Most of us see only the very surface of these diverse applications. Today I will quickly review what a laser is and how its unique properties make it applicable in the field of medicine. I will then show you some of the many different ways in which lasers are presently used, describe to you the major markets and companies presently engaged in the manufacture of medical lasers, and, importantly, share with you some thoughts about the future of lasers in medicine.

  1. Femtosecond laser materials processing

    SciTech Connect

    Stuart, B

    1998-08-05

    Femtosecond lasers enable materials processing of most any material with extremely high precision and negligible shock or thermal loading to the surrounding area. Applications ranging from drilling teeth to cutting explosives to precision cuts in composites are possible by using this technology. For material removal at reasonable rates, we have developed a fully computer-controlled 15-Watt average power, 100-fs laser machining system.

  2. CANALOPLASTY AFTER LASER TRABECULOPLASTY.

    PubMed

    Caileanu, Gabriela Denisa

    2015-01-01

    The paper presents a case of a pseudoexfoliative glaucoma previously treated with argon laser trabeculoplasty in a tertiary center, who was scheduled for canaloplasty in the Ophthalmology Department of the County Hospital Piatra Neamt, Romania. Although the status post laser trabeculoplasty is not among the best indications for canaloplasty, the article confirms the fact that this procedure can also be successfully performed in these cases.

  3. Laser space propulsion overview

    NASA Astrophysics Data System (ADS)

    Phipps, Claude; Luke, James; Helgeson, Wesley

    2007-03-01

    In this paper, we review the history of laser space propulsion from its earliest theoretical conceptions to modern practical applicatons. Applications begin with the "Lightcraft" flights of Myrabo and include practical thrusters for satellites now completing development as well as proposals for space debris removal and direct launch of payloads into orbit. We consider laser space propulsion in the most general sense, in which laser radiation is used to propel a vehicle in space. In this sense, the topic includes early proposals for pure photon propulsion, laser ablation propulsion, as well as propulsion using lasers to detonate a gas, expel a liquid, heat and expel a gas, or even to propagate power to a remote conventional electric thruster. We also discuss the most recent advances in LSP. For the first time, it is possible to consider space propulsion engines which exhibit thrust of one to several newtons while simultaneously delivering 3,000 seconds, or greater, specific impulse. No other engine concept can do both in a compact format. These willl use onboard, rather than remote, lasers. We will review the concept of chemically augmented electric propulsion, which can provide overall thrust efficiency greater than unity while maintaining very low mass to power ratio, high mean time to failure and broad operating range. The main advantage of LSP is exhaust velocity which can be instantaneously varied from 2km/s to 30km/s, simply by varying laser pulsewidth and focal spot size on target. The laser element will probably be a diode-pumped, fiber master-oscillator-power-amplifier (MOPA) system. Liquid fuels are necessary for volumetric efficiency and reliable performance at the multi-kW optical power levels required for multi-N thrust.

  4. Stabilized Laser Gravimeter

    DTIC Science & Technology

    1976-11-01

    McMullen, "Stabilized Laser Gravim- eter," Proceedings of the 20th International Instrumentations Symposium, Albuquerque, New Mexico , May 1974. N.D...and N.D. McMullen, "Stabilized Laser Gravimeter," Proceedings of the 20th International Instrumentations Symposium, Albuquerque, New Mexico , May 1974...International Instrumentations *i, Albuquerque, New Mexico , May 1974. 3. J. Levine and J.L. Hall, "Design and Operation of a Methane Absorp- tion Stabilized

  5. Laser Initiated Actuator study

    SciTech Connect

    Watson, B.

    1991-06-27

    The program task was to design and study a laser initiated actuator. The design of the actuator is described, it being comprised of the fiber and body subassemblies. The energy source for all experiments was a Spectra Diode 2200-H2 laser diode. The diode is directly coupled to a 100 micron core, 0.3 numerical aperture fiber optic terminated with an SMA connector. The successful testing results are described and recommendations are made.

  6. Insulator for laser housing

    DOEpatents

    Duncan, D.B.

    1992-12-29

    The present invention provides a heat-resistant electrical insulator adapted for joining laser housing portions, which insulator comprises: an annulus; a channel in the annulus traversing the circumference and length of the housing; at least two ports, each communicating with the channel and an outer surface of the housing; and an attachment for securely attaching each end of the annulus to a laser housing member. 3 figs.

  7. Insulator for laser housing

    DOEpatents

    Duncan, David B.

    1992-01-01

    The present invention provides a heat-resistant electrical insulator adapted for joining laser housing portions, which insulator comprises: an annulus; a channel in the annulus traversing the circumference and length of the housing; at least two ports, each communicating with the channel and an outer surface of the housing; and an attachment for securely attaching each end of the annulus to a laser housing member.

  8. Laser gingivectomy for pediatrics.

    PubMed

    Kelman, Michelle M; Poiman, David J; Jacobson, Barry L

    2010-01-01

    Traditional gingivectomy procedures have been a challenge for pediatric dentists who confront issues of patient cooperation and discomfort. Treatment of pediatric patients must involve minimal operative and postoperative discomfort. Laser soft-tissue surgery has been shown to be well accepted by children. For the pediatric patient, the greatest advantage of the laser is the lack of local anesthesia injection and the associated pre- and postoperative discomfort. The following case report describes a gingivectomy procedure performed on a 14-year-old female.

  9. Lasers and Optics

    DTIC Science & Technology

    2013-03-05

    PCI Measurements in YAG Al2O3 single crystal (Standard 1) Fused silica (Standard 2) Reactive Sintered Ceramics Non-Reactive Sintered ...AFRL:! ... J ,, 4 DISTRIBUTION A: Approved for public release; distribution is unlimited. • High Average Power Solid-State Lasers • Ceramic Solid...DISTRIBUTION A: Approved for public release; distribution is unlimited. • Ceramic Solid-State Laser Materials • Spatially Varying Index and Doping

  10. Laser Metalworking Technology Transfer.

    DTIC Science & Technology

    1986-01-01

    development work relating to the laser hardfacing of aircraft S-"carrier catapult rails have been performed, and preliminary techniques and...processing data established for different combin- ations of hardfacing alloys/substrate materials. All the laser processing performed in this program was...such cladding. Speci- fically, it was desired to develop methods for cladding the rail material with hardfacing alloys having approximately the same

  11. Competition Effects in Lasers.

    DTIC Science & Technology

    1980-11-01

    Laser", L. Mandel, in Optica Hoy Y Manana-ICO-ll, eds. J. Bescos, A. Hidalgo, L. Plaza and J. Santamaria ( Sociedad Espanola de Optica, Madrid, 1979) pp...previously derived equations for two-mode lasers. 24. " Inversion Problem in Photon Counting with Dead Time", L. Mandel, J. Opt. Soc. Am. 70, 873-874 (1980...temporal variation of atomiz inversion on the fluctuation proper- ties have been investigated in the coherent state diagonal representation of the

  12. Semiconductor microcavity lasers

    SciTech Connect

    Gourley, P.L.; Wendt, J.R.; Vawter, G.A.; Warren, M.E.; Brennan, T.M.; Hammons, B.E.

    1994-02-01

    New kinds of semiconductor microcavity lasers are being created by modern semiconductor technologies like molecular beam epitaxy and electron beam lithography. These new microcavities exploit 3-dimensional architectures possible with epitaxial layering and surface patterning. The physical properties of these microcavities are intimately related to the geometry imposed on the semiconductor materials. Among these microcavities are surface-emitting structures which have many useful properties for commercial purposes. This paper reviews the basic physics of these microstructured lasers.

  13. Laser cooling of solids

    SciTech Connect

    Epstein, Richard I; Sheik-bahae, Mansoor

    2008-01-01

    We present an overview of solid-state optical refrigeration also known as laser cooling in solids by fluorescence upconversion. The idea of cooling a solid-state optical material by simply shining a laser beam onto it may sound counter intuitive but is rapidly becoming a promising technology for future cryocooler. We chart the evolution of this science in rare-earth doped solids and semiconductors.

  14. Laser ophthalmological trainer

    NASA Astrophysics Data System (ADS)

    Sovva, Anatoly I.; Strinadko, Miroslav T.; Strinadko, Marina M.

    1997-12-01

    The laser ophthalmological trainer is offered. It provides stimulation of an optic analyzer by means of the simultaneous influence of different sensor zones optic auditory by the modulated laser radiation and the sound signal of the proper frequency. The trainer includes the assembly providing individual control of the permissible dose of radiation and can be used for treatment of partial atrophy of optic nerve, dystrophy of cornea, cornea syndrome after refraction surgery, inflammatory diseases of cornea, and conjunctivitis.

  15. Femtosecond laser materials processing

    SciTech Connect

    Stuart, B. C., LLNL

    1998-06-02

    Femtosecond lasers enable materials processing of most any material with extremely high precision and negligible shock or thermal loading to the surrounding area Applications ranging from drilling teeth to cutting explosives to making high-aspect ratio cuts in metals with no heat-affected zone are made possible by this technology For material removal at reasonable rates, we developed a fully computer-controlled 15-Watt average power, 100-fs laser machining system.

  16. Ceramic Laser Materials

    SciTech Connect

    Soules, T F; Clapsaddle, B J; Landingham, R L; Schaffers, K I

    2005-02-15

    Transparent ceramic materials have several major advantages over single crystals in laser applications, not the least of which is the ability to make large aperture parts in a robust manufacturing process. After more than a decade of working on making transparent YAG:Nd, Japanese workers have recently succeeded in demonstrating samples that performed as laser gain media as well as their single crystal counterparts. Since then several laser materials have been made and evaluated. For these reasons, developing ceramic laser materials is the most exciting and futuristic materials topic in today's major solid-state laser conferences. We have established a good working relationship with Konoshima Ltd., the Japanese producer of the best ceramic laser materials, and have procured and evaluated slabs designed by us for use in our high-powered SSHCL. Our measurements indicate that these materials will work in the SSHCL, and we have nearly completed retrofitting the SSHCL with four of the largest transparent ceramic YAG:Nd slabs in existence. We have also begun our own effort to make this material and have produced samples with various degrees of transparency/translucency. We are in the process of carrying out an extensive design-of-experiments to establish the significant process variables for making transparent YAG. Finally because transparent ceramics afford much greater flexibility in the design of lasers, we have been exploring the potential for much larger apertures, new materials, for example for the Mercury laser, other designs for SSHL, such as, edge pumping designs, slabs with built in ASE suppression, etc. This work has just beginning.

  17. Variable laser attenuator

    DOEpatents

    Foltyn, Stephen R.

    1988-01-01

    The disclosure relates to low loss, high power variable attenuators comprng one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength.

  18. Cylindrical laser resonator

    DOEpatents

    Casperson, Lee W.

    1976-02-24

    The properties of an improved class of lasers is presented. In one configuration of these lasers the radiation propagates radially within the amplifying medium, resulting in high fields and symmetric illumination at the resonator axis. Thus there is a strong focusing of energy at the axis of the resonator. In a second configuration the radiation propagates back and forth in a tubular region of space.

  19. Variable laser attenuator

    DOEpatents

    Foltyn, S.R.

    1987-05-29

    The disclosure relates to low loss, high power variable attenuators comprising one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength. 9 figs.

  20. Transmyocardial laser revascularization

    NASA Astrophysics Data System (ADS)

    Aretz, H. Thomas

    1996-09-01

    Transmyocardial laser revascularization (TMR) for the treatment of medically unresponsive angina pectoris has been shown to be clinically effective. The mechanism of its action, however, is not quite understood. Over the last five years my collaborators and I have conducted a variety of in vivo and in vitro studies using different animal models, lasers and experimental protocols. The results seem to indicate that the mechanism of action of TMR is related to neovascularization rather than chronically patent channels, as originally proposed.

  1. Laser angle sensor

    NASA Technical Reports Server (NTRS)

    Pond, C. R.; Texeira, P. D.

    1985-01-01

    A laser angle measurement system was designed and fabricated for NASA Langley Research Center. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the model. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. This report includes optical and electrical schematics, system maintenance and operation procedures.

  2. Pulsed gas laser

    DOEpatents

    Anderson, Louis W.; Fitzsimmons, William A.

    1978-01-01

    A pulsed gas laser is constituted by Blumlein circuits wherein space metal plates function both as capacitors and transmission lines coupling high frequency oscillations to a gas filled laser tube. The tube itself is formed by spaced metal side walls which function as connections to the electrodes to provide for a high frequency, high voltage discharge in the tube to cause the gas to lase. Also shown is a spark gap switch having structural features permitting a long life.

  3. Laser range profile of cones

    NASA Astrophysics Data System (ADS)

    Zhou, Wenzhen; Gong, Yanjun; Wang, Mingjun; Gong, Lei

    2016-10-01

    technology. Laser one-dimensional range profile can reflect the characteristics of the target shape and surface material. These techniques were motivated by applications of laser radar to target discrimination in ballistic missile defense. The radar equation of pulse laser about cone is given in this paper. This paper demonstrates the analytical model of laser one-dimensional range profile of cone based on the radar equation of the pulse laser. Simulations results of laser one-dimensional range profiles of some cones are given. Laser one-dimensional range profiles of cone, whose surface material with diffuse lambertian reflectance, is given in this paper. Laser one-dimensional range profiles of cone, whose surface mater with diffuse materials whose retroreflectance can be modeled closely with an exponential term that decays with increasing incidence angles, is given in this paper. Laser one-dimensional range profiles of different pulse width of cone is given in this paper. The influences of surface material, pulse width, attitude on the one-dimensional range are analyzed. The laser two-dimensional range profile is two-dimensional scattering imaging of pulse laser of target. The two-dimensional range profile of roughness target can provide range resolved information. An analytical model of two-dimensional laser range profile of cone is proposed. The simulations of two-dimensional laser range profiles of some cones are given. Laser two-dimensional range profiles of cone, whose surface mater with diffuse lambertian reflectance, is given in this paper. Laser two-dimensional range profiles of cone, whose surface mater with diffuse materials whose retroreflectance can be modeled closely with an exponential term that decays with increasing incidence angles, is given in this paper. The influence of pulse width, surface material on laser two-dimensional range profile is analyzed. Laser one-dimensional range profile and laser two-dimensional range profile are called as laser

  4. Underwater laser detection system

    NASA Astrophysics Data System (ADS)

    Gomaa, Walid; El-Sherif, Ashraf F.; El-Sharkawy, Yasser H.

    2015-02-01

    The conventional method used to detect an underwater target is by sending and receiving some form of acoustic energy. But the acoustic systems have limitations in the range resolution and accuracy; while, the potential benefits of a laserbased underwater target detection include high directionality, high response, and high range accuracy. Lasers operating in the blue-green region of the light spectrum(420 : 570nm)have a several applications in the area of detection and ranging of submersible targets due to minimum attenuation through water ( less than 0.1 m-1) and maximum laser reflection from estimated target (like mines or submarines) to provide a long range of detection. In this paper laser attenuation in water was measured experimentally by new simple method by using high resolution spectrometer. The laser echoes from different targets (metal, plastic, wood, and rubber) were detected using high resolution CCD camera; the position of detection camera was optimized to provide a high reflection laser from target and low backscattering noise from the water medium, digital image processing techniques were applied to detect and discriminate the echoes from the metal target and subtract the echoes from other objects. Extraction the image of target from the scattering noise is done by background subtraction and edge detection techniques. As a conclusion, we present a high response laser imaging system to detect and discriminate small size, like-mine underwater targets.

  5. Wurtzite spin lasers

    NASA Astrophysics Data System (ADS)

    Faria Junior, Paulo E.; Xu, Gaofeng; Chen, Yang-Fang; Sipahi, Guilherme M.; Žutić, Igor

    2017-03-01

    Semiconductor lasers are strongly altered by adding spin-polarized carriers. Such spin lasers could overcome many limitations of their conventional (spin-unpolarized) counterparts. While the vast majority of experiments in spin lasers employed zinc-blende semiconductors, the room-temperature electrical manipulation was first demonstrated in wurtzite GaN-based lasers. However, the underlying theoretical description of wurtzite spin lasers is still missing. To address this situation, focusing on (In,Ga)N-based wurtzite quantum wells, we develop a theoretical framework in which the calculated microscopic spin-dependent gain is combined with a simple rate equation model. A small spin-orbit coupling in these wurtzites supports simultaneous spin polarizations of electrons and holes, providing unexplored opportunities to control spin lasers. For example, the gain asymmetry, as one of the key figures of merit related to spin amplification, can change the sign by simply increasing the carrier density. The lasing threshold reduction has a nonmonotonic dependence on electron-spin polarization, even for a nonvanishing hole spin polarization.

  6. Laser double Doppler flowmeter

    NASA Astrophysics Data System (ADS)

    Poffo, L.; Goujon, J.-M.; Le Page, R.; Lemaitre, J.; Guendouz, M.; Lorrain, N.; Bosc, D.

    2014-05-01

    The Laser Doppler flowmetry (LDF) is a non-invasive method for estimating the tissular blood flow and speed at a microscopic scale (microcirculation). It is used for medical research as well as for the diagnosis of diseases related to circulatory system tissues and organs including the issues of microvascular flow (perfusion). It is based on the Doppler effect, created by the interaction between the laser light and tissues. LDF measures the mean blood flow in a volume formed by the single laser beam, that penetrate into the skin. The size of this measurement volume is crucial and depends on skin absorption, and is not directly reachable. Therefore, current developments of the LDF are focused on the use of always more complex and sophisticated signal processing methods. On the other hand, laser Double Doppler Flowmeter (FL2D) proposes to use two laser beams to generate the measurement volume. This volume would be perfectly stable and localized at the intersection of the two laser beams. With FL2D we will be able to determine the absolute blood flow of a specific artery. One aimed application would be to help clinical physicians in health care units.

  7. Laser Transmitter Aims At Laser Beacon

    NASA Technical Reports Server (NTRS)

    Hemmati, Hamid; Lesh, James R.

    1993-01-01

    Transmitter part of developmental optical communication system. Compact, lightweight, partially-self-aiming laser transmitter built to verify some capabilities of developmental free-space optical communication system. Design capable of providing 0.5 Mbps data return over range equal to Moon-Earth distance. Breadboard of transmitting terminal constructed and tested in laboratory. Prototype transmitter includes receiving circuitry that keeps it aimed at beacon, once brought into initial alignment within about 1.7 degrees of line of sight to beacon.

  8. Laser Development for Laser Fusion Applications

    DTIC Science & Technology

    1978-09-01

    the Z-80 microprocessor to process the fringe pattern, incorporating items 2 and 3 above. Currently, the Reticon data can be read and processed...COLLIMATING TELESCOPE RETICON PHOTODIODE ARRAY ADC ^PROCESSOR SUBSYSTEM FIZEAU COMPENSATING WEDGE PLATE TO WAVELENGTH CONTROLLER Fig. 59...incidence was ~4 degrees, with the Reticon array 30 cm from the wedge. The light source was a single wavelength, from a cw HeNe laser, so no

  9. Lasers '92; Proceedings of the International Conference on Lasers and Applications, 15th, Houston, TX, Dec. 7-10, 1992

    NASA Technical Reports Server (NTRS)

    Wang, Charles P. (Editor)

    1993-01-01

    Papers from the conference are presented, and the topics covered include the following: x-ray lasers, excimer lasers, chemical lasers, high power lasers, blue-green lasers, dye lasers, solid state lasers, semiconductor lasers, gas and discharge lasers, carbon dioxide lasers, ultrafast phenomena, nonlinear optics, quantum optics, dynamic gratings and wave mixing, laser radar, lasers in medicine, optical filters and laser communication, optical techniques and instruments, laser material interaction, and industrial and manufacturing applications.

  10. Laser Ablation for Medical Applications

    NASA Astrophysics Data System (ADS)

    Hayashi, Ken-Ichi

    Medical applications of laser are measurement, laser surgery, in-situ monitoring, and processing of medical devices. In this paper, author briefly reviews the trends of medical applications, describes some new applications, and then discuss about the future trends and problems of medical applications. At present, the domestic market of laser equipment for medical applications is nearly 1/10 of that for industrial applications, which has registered significant growth continuously. Laser surgery as a minimum invasive surgery under arthroscope is expected to decrease the pain of patients. Precise processing such as cutting and welding is suitable for manufacturing medical devices. Pulsed laser deposition has been successfully applied to the thin film coating. The corneal refractive surgery by ArF excimer laser has been widely accepted for its highly safe operation. Laser ablation for retinal implant in the visual prosthesis is one of the promising applications of laser ablation in medicine. New applications with femtosecond laser are expected in the near future.

  11. Information and Communication Using Lasers

    NASA Astrophysics Data System (ADS)

    Alouini, Mehdi; Bretenaker, Fabien

    2015-10-01

    The applications of lasers in industry are numerous. It is of course beyond the scope of this book to give an overview of these applications. Rather than trying and failing in doing so, we have chosen in this chapter to illustrate the unique properties of lasers in four different fields. The two first applications described in this chapter, namely optical telecommunications (Section 3.1) and optical information storage (Section 3.2), highlight the contribution of the spatial coherence of the laser. The third one, namely the ring laser gyroscope (Section 3.3), illustrates the amazing spectral purity that can be provided by laser light. Finally, the fourth one, known under the generic acronym LIDAR (Section 3.4), can use different laser properties, depending on its implementation. It can be based on the laser spatial coherence, the laser temporal coherence, and/or on the laser ability to emit powerful short pulses.

  12. Lasers in endodontics: an overview

    NASA Astrophysics Data System (ADS)

    Frentzen, Matthias; Braun, Andreas; Koort, Hans J.

    2002-06-01

    The interest in endodontic use of dental laser systems is increasing. Developing laser technology and a better understanding of laser effects widened the spectrum of possible endodontic indications. Various laser systems including excimer-, argon+-, diode-, Nd:YAG-, Er:YAG- and CO2-lasers are used in pulp diagnosis, treatment of hypersensitivity, pulp capping, sterilization of root canals, root canal shaping and obturation or apicoectomy. With the development of new delivery systems - thin and flexible fibers - for many different wavelengths laser applications in endodontics may increase. Since laser devices are still relatively costly, access to them is limited. Most of the clinical applications are laser assisted procedures such as the removing of pulp remnants and debris or disinfection of infected root canals. The essential question is whether a laser can provide improved treatment over conventional care. To perform laser therapy in endodontics today different laser types with adopted wavelengths and pulse widths are needed, each specific to a particular application. Looking into the future we will need endodontic laser equipment providing optimal laser parameters for different treatment modalities. Nevertheless, the quantity of research reports from the last decade promises a genuine future for lasers in endodontics.

  13. Surgical Lasers In Gynecology

    NASA Astrophysics Data System (ADS)

    Schellhas, Helmut F.; Barnes, Alfonso E.

    1982-12-01

    Multipurpose surgical CO2 lasers marketed in the USA have been developed to be applicable to a variety of surgical procedures in many surgical fields. They are all suited for endoscopic surgical procedures and can be fitted to all standard surgical microscopes. They all can adjust the focal length of the laser beam to the different standard focal lengths of the surgical microscope which for instance in laryngoscopy is 400 mm and in colposcopy 300 mm. One laser instrument can even change the spot size in a given focal distance which is very advantageous for some microsurgical procedures (Merrimack Laboratories 820). All multipurpose surgical CO2 laser systems provide a multi-articulated surgical arm for free-hand surgery. The surgical arms are cumbersome to use but they are adapted to the surgeons needs with ingenuity. The practicality of the multi-articulated surgical arms depends mostly on the distance of the handpiece from the surgical console which now is also overbridged by the laser tube in most surgical laser system. The spot size of the beam is variable in most handpieces by interchangeable lenses which modify the focal distance of the beam and the power density. Another common feature in all systems is a coaxial He-Ne pilot light which provides a red spot which unfortunately becomes invisible in a bleeding surgical field. Most surgical laser systems have a spacial mode of TEM 00 which is essential for incisional surgery. The continuous mode of beam delivery is used for incisional surgery and also for most endoscopic procedures.

  14. Laser fusion pulse shape controller

    DOEpatents

    Siebert, Larry D.

    1977-01-01

    An apparatus for controlling the pulse shape, i.e., the pulse duration and intensity pattern, of a pulsed laser system, and which is particularly well adapted for controlling the pellet ignition pulse in a laser-driven fusion reaction system. The apparatus comprises a laser generator for providing an optical control pulse of the shape desired, a pulsed laser triggered by the control pulse, and a plurality of optical Kerr-effect gates serially disposed at the output of the pulsed laser and selectively triggered by the control pulse to pass only a portion of the pulsed laser output generally corresponding in shape to the control pulse.

  15. Injection-controlled laser resonator

    DOEpatents

    Chang, Jim J.

    1995-07-18

    A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality.

  16. High power ultrashort pulse lasers

    SciTech Connect

    Perry, M.D.

    1994-10-07

    Small scale terawatt and soon even petawatt (1000 terawatt) class laser systems are made possible by application of the chirped-pulse amplification technique to solid-state lasers combined with the availability of broad bandwidth materials. These lasers make possible a new class of high gradient accelerators based on the large electric fields associated with intense laser-plasma interactions or from the intense laser field directly. Here, we concentrate on the laser technology to produce these intense pulses. Application of the smallest of these systems to the production of high brightness electron sources is also introduced.

  17. Blue-green upconversion laser

    SciTech Connect

    Nguyen, Dinh C.; Faulkner, George E.

    1990-01-01

    A blue-green laser (450-550 nm) uses a host crystal doped with Tm.sup.3+. The Tm.sup.+ is excited through upconversion by a red pumping laser and an IR pumping laser to a state which transitions to a relatively lower energy level through emissions in the blue-green band, e.g., 450.20 nm at 75 K. The exciting laser may be tunable dye lasers or may be solid-state semiconductor laser, e.g., GaAlAs and InGaAlP.

  18. Injection-controlled laser resonator

    DOEpatents

    Chang, J.J.

    1995-07-18

    A new injection-controlled laser resonator incorporates self-filtering and self-imaging characteristics with an efficient injection scheme. A low-divergence laser signal is injected into the resonator, which enables the injection signal to be converted to the desired resonator modes before the main laser pulse starts. This injection technique and resonator design enable the laser cavity to improve the quality of the injection signal through self-filtering before the main laser pulse starts. The self-imaging property of the present resonator reduces the cavity induced diffraction effects and, in turn, improves the laser beam quality. 5 figs.

  19. Blue-green upconversion laser

    DOEpatents

    Nguyen, D.C.; Faulkner, G.E.

    1990-08-14

    A blue-green laser (450--550 nm) uses a host crystal doped with Tm[sup 3+]. The Tm[sup 3+] is excited through upconversion by a red pumping laser and an IR pumping laser to a state which transitions to a relatively lower energy level through emissions in the blue-green band, e.g., 450.20 nm at 75 K. The exciting laser may be tunable dye lasers or may be solid-state semiconductor laser, e.g., GaAlAs and InGaAlP. 3 figs.

  20. A High Power Frequency Doubled Fiber Laser

    NASA Technical Reports Server (NTRS)

    Thompson, Rob; Tu, Meirong; Aveline, Dave; Lundblad, Nathan; Maleki, Lute

    2003-01-01

    This slide presentation reviews the power frequencies for the doubled fiber laser. It includes information on the 780 nm laser, second harmonic generation in one crystal, cascading crystals, the tenability of laser systems, laser cooling, and directions for future work.