Lateral sesamoid position in hallux valgus: correlation with the conventional radiological assessment.

PubMed

Agrawal, Yuvraj; Desai, Aravind; Mehta, Jaysheel

2011-12-01

We aimed to quantify the severity of the hallux valgus based on the lateral sesamoid position and to establish a correlation of our simple assessment method with the conventional radiological assessments. We reviewed one hundred and twenty two dorso-plantar weight bearing radiographs of feet. The intermetatarsal and hallux valgus angles were measured by the conventional methods; and the position of lateral sesamoid in relation to first metatarsal neck was assessed by our new and simple method. Significant correlation was noted between intermetatarsal angle and lateral sesamoid position (Rho 0.74, p < 0.0001); lateral sesamoid position and hallux valgus angle (Rho 0.56, p < 0.0001). Similar trends were noted in different grades of severity of hallux valgus in all the three methods of assessment. Our method of assessing hallux valgus deformity based on the lateral sesamoid position is simple, less time consuming and has statistically significant correlation with that of the established conventional radiological measurements. Copyright © 2011 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Valgus extension overload syndrome and stress injury of the olecranon.

PubMed

Ahmad, Christopher S; ElAttrache, Neal S

2004-10-01

Basic science studies have improved our understanding of the pathomechanics for valgus extension overload and olecranon stress fractures. These disorders result from repetitive abutment of the olecranon into the olecranon fossa combined with valgus torques, resulting in impaction and shear along the posteromedial olecranon. The patient history and physical examination are similar for each disorder. Imaging studies including plain radiographs, computed tomography, MRI or bone scan may be necessary for accurate diagnosis. Clinical and basic science support mandatory and careful assessment of the medial collateral ligament when valgus extension overload is identified and limited debridement of the olecranon when surgery is indicated. For stress fractures that fail nonoperative management, treatment with internal fixation provides good results.

Reliability of Two Smartphone Applications for Radiographic Measurements of Hallux Valgus Angles.

PubMed

Mattos E Dinato, Mauro Cesar; Freitas, Marcio de Faria; Milano, Cristiano; Valloto, Elcio; Ninomiya, André Felipe; Pagnano, Rodrigo Gonçalves

The objective of the present study was to assess the reliability of 2 smartphone applications compared with the traditional goniometer technique for measurement of radiographic angles in hallux valgus and the time required for analysis with the different methods. The radiographs of 31 patients (52 feet) with a diagnosis of hallux valgus were analyzed. Four observers, 2 with >10 years' experience in foot and ankle surgery and 2 in-training surgeons, measured the hallux valgus angle and intermetatarsal angle using a manual goniometer technique and 2 smartphone applications (Hallux Angles and iPinPoint). The interobserver and intermethod reliability were estimated using intraclass correlation coefficients (ICCs), and the time required for measurement of the angles among the 3 methods was compared using the Friedman test. A very good or good interobserver reliability was found among the 4 observers measuring the hallux valgus angle and intermetatarsal angle using the goniometer (ICC 0.913 and 0.821, respectively) and iPinPoint (ICC 0.866 and 0.638, respectively). Using the Hallux Angles application, a very good interobserver reliability was found for measurements of the hallux valgus angle (ICC 0.962) and intermetatarsal angle (ICC 0.935) only among the more experienced observers. The time required for the measurements was significantly shorter for the measurements using both smartphone applications compared with the goniometer method. One smartphone application (iPinPoint) was reliable for measurements of the hallux valgus angles by either experienced or nonexperienced observers. The use of these tools might save time in the evaluation of radiographic angles in the hallux valgus. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Finite element analysis of the valgus knee joint of an obese child.

PubMed

Sun, Jun; Yan, Songhua; Jiang, Yan; Wong, Duo Wai-Chi; Zhang, Ming; Zeng, Jizhou; Zhang, Kuan

2016-12-28

Knee valgus and varus morbidity is at the second top place in children lower limb deformity diseases. It may cause abnormal stress distribution. The magnitude and location of contact forces on tibia plateau during gait cycle have been indicated as markers for risk of osteoarthritis. So far, few studies reported the contact stress and force distribution on tibial plateau of valgus knee of children. To estimate the contact stresses and forces on tibial plateau of an 8-year old obese boy with valgus knee and a 7-year old healthy boy, three-dimensional (3D) finite element (FE) models of their left knee joints were developed. The valgus knee model has 36,897 nodes and 1,65,106 elements, and the normal knee model has 78,278 nodes and 1,18,756 elements. Paired t test was used for the comparison between the results from the 3D FE analysis method and the results from traditional kinematic measurement methods. The p value of paired t test is 0.12. Maximum stresses shifted to lateral plateau in knee valgus children while maximum stresses were on medial plateau in normal knee child at the first peak of vertical GRF of stance phase. The locations of contact centers on medial plateau changed 3.38 mm more than that on lateral plateau, while the locations of contact centers on medial plateau changed 1.22 mm less than that on lateral plateau for healthy child from the first peak to second peak of vertical GRF of stance phase. The paired t test result shows that there is no significant difference between the two methods. The results of FE analysis method suggest that knee valgus malalignment could be the reason for abnormal knee load that may cause knee problems in obese children with valgus knee in the long-term. This study may help to understand biomechanical mechanism of valgus knees of obese children.

Total knee arthroplasty for severe valgus knee deformity.

PubMed

Zhou, Xinhua; Wang, Min; Liu, Chao; Zhang, Liang; Zhou, Yixin

2014-01-01

Primary total knee arthroplasty (TKA) in severe valgus knees may prove challenging, and choice of implant depends on the severity of the valgus deformity and the extent of soft-tissue release. The purpose of this study was to review 8 to 11 years (mean, 10 years) follow-up results of primary TKA for varient-III valgus knee deformity with use of different type implants. Between January 2002 and January 2005, 20 women and 12 men, aged 47 to 63 (mean, 57.19 ± 6.08) years old, with varient-III valgus knees underwent primary TKA. Of the 32 patients, 37 knees had varient-III deformities. Pie crusting was carefully performed with small, multiple inside-out incisions, bone resection balanced the knee in lieu of soft tissue releases that were not used in the series. Cruciate-retaining knees (Gemini MKII, Link Company, Germany) were used in 13 knees, Genesis II (Simth & Nephew Company, USA) in 14 knees, and hinged knee (Endo-Model Company, Germany) in 10 knees. In five patients with bilateral variant-III TKAs, three patients underwent 1-stage bilateral procedures, and two underwent 2-stage procedures. All implants were cemented and the patella was not resurfaced. The Hospital for Special Surgery (HSS) knee score was assessed. Patients were followed up from 8 to 11 years. The mean HSS knee score were improved from 50.33 ± 11.60 to 90.06 ± 3.07 (P < 0.001). The mean tibiofemoral alignment were improved from valgus 32.72° ± 9.68° pre-operation to 4.89° ± 0.90° post-operation (P < 0.001). The mean range of motion were improved from 93.72° ± 23.69° pre-operation to 116.61 ± 16.29° post-operation (P < 0.001). No patients underwent revision. One patient underwent open reduction and internal fixation using femoral condylar plates for supracondylar femoral fractures secondary to a fall at three years. Three patients developed transient peroneal nerve palsies, which resolved within nine months. Two patients developed symptomatic deep vein thrombosis that was managed with

Accuracy of estimating Unicondylar Knee Replacement implant varus/valgus angles from antero-posterior radiographs.

PubMed

Khare, Rahul; Jaramaz, Branislav

2016-12-01

Unicondylar Knee Replacement (UKR) is an orthopedic surgical procedure to reduce pain and improve function in the knee. Load-bearing long-standing antero-posterior (AP) radiographs are typically used postoperatively to measure the leg alignment and assess the varus/valgus implant orientation. However, implant out-of-plane rotations, user variability, and X-ray acquisition parameters introduce errors in the estimation of the implant varus/valgus estimation. Previous work has explored the accuracy of various imaging modalities in this estimation. In this work, we explored the impact of out-of-plane rotations and X-ray acquisition parameters on the estimation of implant component varus/valgus angles. For our study, we used a single CT scan and positioned femoral and tibial implants under varying orientations within the CT volume. Then, a custom software application was used to obtain digitally reconstructed radiographs from the CT scan with implants under varying orientations. Two users were then asked to manually estimate the varus/valgus angles for the implants. We found that there was significant inter-user variability (p < 0.05) in the varus/valgus estimates for the two users. However, the 'ideal' measurements, obtained using actual implant orientations, showed small errors due to variations in implant orientation. We also found that variation in the projection center does not have a statistically significant impact (p < 0.01) on the estimation of implant varus/valgus angles. We conclude that manual estimates of UKR implant varus/valgus orientations are unreliable.

Geometry of the Valgus Knee: Contradicting the Dogma of a Femoral-Based Deformity.

PubMed

Eberbach, Helge; Mehl, Julian; Feucht, Matthias J; Bode, Gerrit; Südkamp, Norbert P; Niemeyer, Philipp

2017-03-01

Realignment osteotomies of valgus knee deformities are usually performed at the distal femur, as valgus alignment is considered to be a femoral-based deformity. This dogma, however, has not been proven in a large patient population. Valgus malalignment may also be caused by a tibial deformity or a combined tibial and femoral deformity. The purposes of this study were (1) to analyze the coronal geometry of patients with valgus malalignment and identify the location of the underlying deformity and (2) to investigate the proportion of cases that require realignment osteotomy at the tibia, the femur, or both locations to avoid an oblique joint line. Cross-sectional study; Level of evidence, 3. The analysis included 420 standing full-leg radiographs of patients with valgus malalignment (mechanical femorotibial angle [mFTA], ≥4°). A systematic analysis of the coronal leg geometry was performed including the mFTA, mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and joint-line convergence angle (JLCA). The localization of the deformity was determined according to the malalignment test described by Paley, and patients were assigned to 1 of 4 groups: femoral-based valgus deformity, tibial-based valgus deformity, femoral- and tibial-based valgus deformity, or intra-articular/ligamentary-based valgus deformity. Subsequently, the ideal osteotomy site was identified with the goal of a postoperative change of the joint line of two different maximum values, ±2° and ±4°, from its physiological varus position of 3°. Measurements of the coronal alignment revealed a mean (±SD) mFTA of 7.4° ± 4.3° (range, 4°-28.2°). The mean mLDFA and mean mMPTA were 84.8° ± 2.4° and 90.9° ± 2.6°, respectively. The mean JLCA was 1.2° ± 3.1°. The majority (41.0%) of valgus deformities were tibial based, 23.6% were femoral based, 26.9% were femoral and tibial based, and 8.6% were intra-articular/ligamentary based. To achieve a

Short-Term Radiographic Outcome After Distal Chevron Osteotomy for Hallux Valgus Using Intramedullary Plates With an Amended Algorithm for the Surgical Management of Hallux Valgus.

PubMed

Matsumoto, Takumi; Gross, Christopher E; Parekh, Selene G

2018-03-01

Distal Chevron osteotomy is a well-established surgical procedure for mild to moderate hallux valgus deformity. Many methods have been described for fixation of osteotomy site; secure fixation, enabling large displacement of the metatarsal head, is one of the essentials of this procedure. The purpose of the present study was to evaluate the short-term radiographic outcome of a distal Chevron osteotomy using an intramedullary plate for the correction of hallux valgus deformity. The present study evaluated 37 patients (40 feet) who underwent distal Chevron osteotomy using an intramedullary plate by periodic radiographs obtained preoperatively and at 4 weeks, 8 weeks, 3 months, and 6 months postoperatively. Correction of the hallux valgus angle averaged 17.8°, intermetatarsal angle 7.4°, distal metatarsal articular angle 2.7°, and sesamoid position 1.4 stages at 3 months postoperatively. The average lateral shift of the capital fragment was 6.5 mm. All patients achieved bone union, and there were no cases of dislocation, displacement, or avascular necrosis of the metatarsal head fragment. In conclusion, a distal Chevron osteotomy using an intramedullary plate was a favorable method for the correction of mild to moderate hallux valgus deformity. Level IV: Case series.

The biomechanical effect of increased valgus on total knee arthroplasty: a cadaveric study.

PubMed

Bryant, Brandon J; Tilan, Justin U; McGarry, Michelle H; Takenaka, Nobuyuki; Kim, William C; Lee, Thay Q

2014-04-01

The effects of valgus load on cadaveric knees following total knee arthroplasty (TKA) were investigated using a custom testing system. TKAs were performed on 8 cadaveric knees and tested at 0°, 30°, and 60° knee flexion in both neutral and 5° valgus. Fuji pressure sensitive film was used to quantify contact areas and pressures and MCL strain was determined using a Microscribe digitizing system. Lateral tibiofemoral pressures increased (P < 0.05) at all knee flexion angles with valgus loading. Patellofemoral contact characteristics did not change significantly (P > 0.05). Significant increases in strain were observed along the anterior and posterior border of the MCL at all knee flexion angles. These findings suggest that valgus loading increases TKA joint contact pressures and MCL strain with increasing knee flexion which may increase implant instability. © 2014.

The Gibson and Piggott osteotomy for adult hallux valgus.

PubMed

Rangrez, Arshad Bashir; Dar, Tahir Ahmed; Badoo, Abdul Rashid; Wani, Sharief Ahmed; Dhar, Shabir Ahmed; Mumtaz, Imran; Ahmed, Muzzaffar

2012-01-01

The Gibson and Piggott procedure for hallux valgus is based on sound surgical principles addressing the basic pathologies of this disorder. However, this procedure has not been studied extensively in the literature in comparison to the Mitchell and Chevron osteotomies. We report a prospective study conducted on 50 adult feet with hallux valgus. The Gibson and Piggot osteotomy was done on all the feet. We obtained 76% excellent and 18% good results with this procedure. The results bear out the fact that this procedure is a useful procedure for the management of this disorder.

Outcomes in chevron osteotomy for Hallux Valgus in a large cohort.

PubMed

van Groningen, Bart; van der Steen, M C Marieke; Reijman, Max; Bos, Janneke; Hendriks, Johannes G E

2016-12-01

Clinical and radiological related outcomes have been reported for Chevron osteotomy as correction for mild to moderate hallux valgus, but only for relatively small patient series. Moreover, evaluation of the patient's point of view has mostly been conducted by means of more physician-based outcome measures. The goal of this study was to evaluate the effect of the Chevron osteotomy for hallux valgus on patients' daily lives using the Foot and Ankle Outcome Score (FAOS) as a validated and a hallux valgus specific patient reported outcome measure (PROM). Secondary outcome measures were radiological correction, complication rate, and re-operations. All 438 Chevron procedures (336 patients), at two surgical hospital sites in the period between January 2010 and October 2014, were retrospectively evaluated with a follow-up of at least 6 months. Patients were invited to fill in a cross-sectional online FAOS. For the FAOS, a total response of 60% was achieved. The FAOS ranged between 71 and 88 with a follow-up of on average 36 months. Patients with an undercorrection of their hallux valgus (11.6% of the procedures) scored significantly lower on three subscales of the FAOS (range between 61 and 77 versus 72-84). Patients who had a reoperation (12.6% of the procedures) also scored significantly lower on four subscales: 58-100 versus 73-89. Postoperative radiological measurements improved significantly with a mean difference of 6.1 (5.9; 6.4) degrees for the intermetatarsal angle and 13.7 (13.0; 14.5) degrees for the hallux valgus angle. In this large study cohort, Chevron osteotomy for hallux valgus offers good PROM scores on FAOS. These scores were significantly lower in patients with radiological undercorrection or with a reoperation. Results of the FAOS appear to modulate with physician based outcomes and therapeutic incidents. Improvement of outcome may therefore well be possible by increased attention on these surgical details. Copyright © 2016 Elsevier Ltd. All rights

A geometric analysis of hallux valgus: correlation with clinical assessment of severity

PubMed Central

Piqué-Vidal, Carlos; Vila, Joan

2009-01-01

Background Application of plane geometry to the study of bunion deformity may represent an interesting and novel approach in the research field of hallux valgus. For the purpose of contributing to development of a different perspective in the assessment of hallux valgus, this study was conducted with three objectives: a) to determine the position on the intersection point of the perpendicular bisectors of the longitudinal axes of the first metatarsal and proximal phalanx (IP), b) to correlate the location of this point with hallux valgus deformity according to angular measurements and according to visual assessment of the severity carried out by three independent observers, and c) to assess whether this IP correlated with the radius of the first metatarsophalangeal arc circumference. Methods Measurements evaluated were intermetatarsal angle (IMA), hallux valgus angle (HVA), and proximal phalangeal articular angle (PPAA). The Autocad® program computed the location of the IP inside or outside of the foot. Three independent observers rated the severity of hallux valgus in photographs using a 100-mm visual analogue scale (VAS). Results Measurements of all angles except PPAA showed significantly lower values when the IP was located out of the foot more distantly and vice versa, significantly higher values for severe deformities in which the IP was found inside the foot (p < 0.001). The IP correlated significantly with VAS scores and with the length of the radius of the circle that included the first metatarsophalangeal arc circumference (p < 0.001) Conclusion The IP is a useful indicator of hallux valgus deformity because correlated significantly with IMA and HVA measurements, VAS scores obtained by visual inspection of the degree of deformity, and location of the center of the first metatarsophalangeal arc circumference. PMID:19442286

[A cadaveric study of a new capsulorrhaphy for the surgical treatment of hallux valgus].

PubMed

Orozco-Villaseñor, S L; Monzó-Planella, M; Martín-Oliva, X; Vázquez-Escamilla, J; Mayagoitia-Vázquez, J J; Frías-Chimal, J E

2017-01-01

There are many surgical options for the treatment of hallux valgus in combination with capsular repairs for the correction of hallux valgus. This report corresponds to a descriptive study where a new capsulorrhaphy technique in hallux valgus is proposed. Six dissections were performed on cadavers with hallux valgus deformity using the following surgical technique: medial approach on the first toe longitudinally, dissecting by planes and locating the metatarsophalangeal joint capsule; it was incised longitudinally. The capsule was separated and an exostectomy of the first metatarsal head was done, the edges were regularized and a release of the abductor hallucis was performed. Later, the capsular remnant was resected and repaired. Six cadaveric feet with hallux valgus were studied, five with mild deformity, one with moderate deformity, one foot with the 2nd finger on supraductus. Many capsular repairs have been reported in the literature, including «L», triangular, «V-Y», rectangular, with satisfactory results, along with osteotomy of the first metatarsal. In this report, a new capsular repair was described. Applying this new capsular repair, we reduced the metatarsophalangeal and intermetatarsal angles and achieved a capsular closure with suitable tension; the metatarsophalangeal joint mobility was preserved.

Hallux abductus interphalangeus in normal feet, early-stage hallux limitus, and hallux valgus.

PubMed

Castillo-Lopez, Jose M; Ramos-Ortega, Javier; Reina-Bueno, Maria; Domínguez-Maldonado, Gabriel; Palomo-Toucedo, Inmaculada C; Munuera, Pedro V

2014-03-01

Excessive deviation of the distal phalanx in abduction frequently occurs in advanced stages of hallux rigidus but not in hallux valgus. Therefore, theoretically there should be no significant differences in the hallux interphalangeal angle (HIPA) between individuals with normal feet, those with hallux valgus, and those with mild hallux limitus. The objective of the present study was thus to determine if significant differences in HIPA exist in the early stages of hallux valgus or hallux limitus deformities. The hallux interphalangeal angle was measured in three groups of participants: a control group with normal feet (45 participants), a hallux valgus group (49 participants), and a hallux limitus group (48 participants). Both of the pathologies were at an early stage. A dorsoplantar radiograph under weightbearing conditions was taken for each individual, and measurements (HIPA and hallux abductus angle [HAA]) were taken using AutoCAD (Autodesk Inc, San Rafael, California) software. Intergroup comparisons of HIPA, and correlations between HIPA, HAA, and hallux dorsiflexion were calculated. The comparisons revealed no significant differences in the values of HIPA between any of the groups (15.2 ± 5.9 degrees in the control group, 15.5 ± 3.9 degrees in the hallux valgus group, and 16.15 ± 4.3 in the hallux limitus group; P  =  0.634). The Pearson correlation coefficients in particular showed no correlation between hallux dorsiflexion, HAA, and HIPA. For the study participants, there were similar deviations of the distal phalanx of the hallux with respect to the proximal phalanx in normal feet and in feet with the early stages of the hallux limitus and hallux valgus deformities.

[Distal osteotomy for the treatment of hallux valgus (Chevron osteotomy)].

PubMed

Stukenborg-Colsman, C; Claaßen, L; Ettinger, S; Yao, D; Lerch, M; Plaaß, C

2017-05-01

Distal osteotomies, like the Chevron osteotomy, is indicated for mild to moderate hallux valgus deformities. Splayfoot, painful pseudoexostosis, and transfer metatasalgia are observed in the clinical examination. Radiographic examination should be done with weight bearing in two planes. Preoperatively the intermetatarsal (IM), hallux valgus, and distal metatarsal articular (DMAA) angles should be measured. The operative technique is based on soft tissue and bony correction. Modifications of the osteotomy allow a shortening, lengthening, or neutral correction of the first metatarsal. With a modified Chevron osteotomy, an increased DMAA can be also corrected.

Evaluating the Quality, Accuracy, and Readability of Online Resources Pertaining to Hallux Valgus.

PubMed

Tartaglione, Jason P; Rosenbaum, Andrew J; Abousayed, Mostafa; Hushmendy, Shazaan F; DiPreta, John A

2016-02-01

The Internet is one of the most widely utilized resources for health-related information. Evaluation of the medical literature suggests that the quality and accuracy of these resources are poor and written at inappropriately high reading levels. The purpose of our study was to evaluate the quality, accuracy, and readability of online resources pertaining to hallux valgus. Two search terms ("hallux valgus" and "bunion") were entered into Google, Yahoo, and Bing. With the use of scoring criteria specific to hallux valgus, the quality and accuracy of online information related to hallux valgus was evaluated by 3 reviewers. The Flesch-Kincaid score was used to determine readability. Statistical analysis was performed with t tests and significance was determined by P values <.05. Sixty-two unique websites were evaluated. Quality was significantly higher with use of the search term "bunion" as compared to "hallux valgus" (P = .045). Quality and accuracy were significantly higher in resources authored by physicians as compared to nonphysicians (quality, P = .04; accuracy, P < .001) and websites without commercial bias (quality, P = .038; accuracy, P = .011). However, the reading level was significantly more advanced for websites authored by physicians (P = .035). Websites written above an eighth-grade reading level were significantly more accurate than those written at or below an eighth-grade reading level (P = .032). The overall quality of online information related to hallux valgus is poor and written at inappropriate reading levels. Furthermore, the search term used, authorship, and presence of commercial bias influence the value of these materials. It is important for orthopaedic surgeons to become familiar with patient education materials, so that appropriate recommendations can be made regarding valuable resources. Level IV. © 2015 The Author(s).

[The Akin procedure as closing wedge osteotomy for the correction of a hallux valgus interphalangeus deformity].

PubMed

Arnold, Heino

2008-12-01

Realignment of the great toe in the case of a hallux valgus interphalangeus by means of a medially based closing wedge osteotomy. Hallux valgus interphalangeus deformity, characterized by an enlarged distal articular surface angle (> 10 degrees). Correction of a hallux valgus interphalangeus deformity as an additional procedure in the case of hallux valgus surgery. Incongruent first metatarsophalangeal joint with lateral subluxation of the proximal phalanx. Isolated procedure to correct hallux valgus deformity. Lack of patient compliance. Neurovascular disturbance of the forefoot. Medially based closing wedge osteotomy of the proximal phalanx to reduce the distal articular surface angle. Fixation with a lag screw, cannulated Herbert screw, memory cramp, threaded Kirschner wire, or interosseous suture. Wound dressing to assure the position of the great toe. Radiographic documentation of the forefoot in two planes. Strict elevation of the operated foot to prevent postoperative swelling. Mobilization of the patient with a forefoot relief orthosis, until consolidation of the osteotomy is verified radiologically (4-5 weeks). Low-molecular-weight heparin for at least 1 week. Hallux valgus bandage or functional taping for 6 weeks postoperatively in patients with additional metatarsal osteotomy. Clinical and radiologic follow-up based on 32 patients showed good results. The postoperative Hallux Score of the American Orthopaedic Foot and Ankle Society improved to 89 points.

Hallux valgus correction using transarticular lateral release with distal chevron osteotomy.

PubMed

Choi, Young Rak; Lee, Ho Seong; Jeong, Jae Jung; Kim, Sang Woo; Jeon, In-Ho; Lee, Dong Ho; Lee, Woo Chun

2012-10-01

Transarticular lateral release through a medial incision can avoid a dorsal incision. This study investigated outcomes following hallux valgus correction using transarticular lateral release, distal chevron metatarsal osteotomy and Akin phalangeal osteotomy through one medial incision. Between June 2004 and May 2009, a single surgeon performed a transarticular lateral release, distal chevron metatarsal osteotomy and Akin phalangeal osteotomy through one medial incision for hallux valgus on a total of 103 feet of 68 patients. The average patient age at the time of surgery was 51 years, and the average followup was 27 months. The average preoperative and final followup results were: 1) hallux valgus angle improvement from 29 degrees to 5 degrees, 2) intermetatarsal angle from 13 degrees to 5 degrees and 3) medial sesamoid bone position from 3 to 1 (p < 0.05 for each variable). The average AOFAS scores were improved from 49 to 92, and the VAS pain scores were improved from 7 to 1 (p < 0.05 for both variables). No patient had a serious complication such as infection, avascular necrosis, nonunion, transfer-metatarsalgia, or first metatarsophalangeal joint arthritis. Hallux valgus correction using transarticular lateral release, distal chevron metatarsal osteotomy and Akin phalangeal osteotomy through one medial incision was found to be effective and safe. The advantages include that the procedure is simple, early ambulation is possible, and there is no dorsal scarring.

Short-Term Effects of Kinesiotaping on Pain and Joint Alignment in Conservative Treatment of Hallux Valgus.

PubMed

Karabicak, Gul Oznur; Bek, Nilgun; Tiftikci, Ugur

2015-10-01

The main aim of this study was to measure short-term effects of kinesiotaping on pain and joint alignment in the conservative treatment of hallux valgus. Twenty-one female patients diagnosed with a total of 34 feet with hallux valgus (13 bilateral, 6 right, and 2 left) participated in this study. Kinesiotaping was implemented after the first assessment and renewed in days 3, 7, and 10. The main outcome measures were pain, as assessed using visual analog scale, and hallux adduction angle, as measured by goniometry. Secondary outcome measure was patients' functional status, as measured by Foot Function Index and the hallux valgus scale of the American Orthopaedic Foot and Ankle Society (AOFAS). The radiographic results were also measured before and after 1 month of treatment. The Wilcoxon test was used to compare the differences between initial and final scores of AOFAS, as well as FFI scales and hallux valgus angle assessment scores. There was a significant reduction in goniometric measurement of hallux valgus angle (P = .001). There was a significant reduction in pain intensity (P = .001) and AOFAS and Foot Function Index scores at the end of the treatment (P = .001 and P = .001, respectively). There was a significant difference between radiographic results in 1-month control (P = .009). For this group of female patients, pain and joint alignment were improved after a 10-day kinesiotape implementation in patients with hallux valgus. The findings showed short-term decreased pain and disability in hallux valgus deformity. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

Comparative study of scarf and extended chevron osteotomies for correction of hallux valgus.

PubMed

Vopat, Bryan G; Lareau, Craig R; Johnson, Julie; Reinert, Steven E; DiGiovanni, Christopher W

2013-12-01

Scarf and chevron osteotomies are two described treatments for the correction of hallux valgus deformity, but they have traditionally been employed for different levels of severity. We hypothesized that there would be no statistically significant difference between the results of these two treatments. This study is a retrospective review of 70 consecutive patients treated operatively for moderate and severe hallux valgus malalignment. The two groups based on their operative treatment: scarf osteotomy (Group A) and extended chevron osteotomy (Group B). Preoperative and postoperative hallux valgus angle (HVA), intermetatarsal angle and distal metatarsal articular angle (DMAA) were measured at final follow-up. Charts were also assessed to determine the postoperative rate of satisfaction, stiffness, and pain. There were no statistically significant differences between Groups A and B with regard to the HVA preoperatively and postoperatively. The DMAA was statistically significantly higher for Group B both preoperatively (p=0.0403) and postoperatively (p<0.0001). The differences in HVA correction and IMA correction were not statistically significant. There were no statistically significant differences with regard to post-operative stiffness, pain, and satisfaction. The scarf and extended chevron osteotomies are capable of adequately reducing the HVA and IMA in patients with moderate to severe hallux valgus. These two techniques yielded similar patient outcomes in terms of stiffness, pain and satisfaction. Based on these results, we recommend both the scarf and extended chevron osteotomy as acceptable forms of correction for moderate to severe hallux valgus.

Location of the Common Peroneal Nerve in Valgus Knees-Is the Reported Safe Zone for Well-Aligned Knees Applicable?

PubMed

Yang, Dejin; Shao, Hongyi; Zhou, Yixin; Tang, Hao; Guo, Shengjie

2017-11-01

Lateral soft-tissue release can jeopardize the common peroneal nerve (CPN) in total knee arthroplasty for valgus knees. Previous studies reporting safe zones to protect the CPN were based on well-aligned knees. We conducted this study to compare the localization of the CPN in well-aligned knees and in valgus knees. We conducted a consecutive 3-dimensional radiographic study on magnetic resonance images of 58 well-aligned knees and 39 valgus knees. We measured the distance between the CPN and the tibia, as well as the mediolateral, anteroposterior, and angular location of the CPN. We compared the results between well-aligned knees and valgus knees. We found that there is an increased distance between the CPN and the tibia at the level of the tibial cut, but not at the joint line in valgus knees. It is safer to release the posterolateral capsule at the tibial side than at the level above this. The angular location and the mediolateral or anteroposterior location of the CPN in valgus knees are similar to those of well-aligned knees. The location of the CPN in valgus knees is similar to that in well-aligned knees. The previously reported safe zone in well-aligned knees is applicable in valgus knees to protect the CPN. Copyright © 2017 Elsevier Inc. All rights reserved.

Z-osteotomy in hallux valgus: clinical and radiological outcome after Scarf osteotomy

PubMed Central

Jäger, Marcus; Schmidt, Michael; Wild, Alexander; Bittersohl, Bernd; Courtois, Susanne; Schmidt, Troy G.; Rüdiger, Krauspe

2009-01-01

Correction osteotomies of the first metatarsal are common surgical approaches in treating hallux valgus deformities whereas the Scarf osteotomy has gained popularity. The purpose of this study was to analyze short- and mid-term results in hallux valgus patients who underwent a Scarf osteotomy. The subjective and radiological outcome of 131 Scarf osteotomies (106 hallux valgus patients, mean age: 57.5 years, range: 22–90 years) were retrospectively analyzed. Mean follow-up was 22.4 months (range: 6 months–5 years). Surgical indications were: intermetatarsal angle (IMA) of 12–23°; increased proximal articular angle (PAA>8°), and range of motion of the metatarsophalangeal joint in flexion and extension >40°. Exclusion criteria were severe osteoporosis and/or osteoarthritis. The mean subjective range of motion (ROM) of the great toe post-surgery was 0.8±1.73 points (0: full ROM, 10: total stiffness). The mean subjective cosmetic result was 2.7±2.7 points (0: excellent, 10: poor). The overall post-operative patient satisfaction with the result was high (2.1±2.5 points (0: excellent, 10: poor). The mean hallux valgus angle improvement was 16.6° (pre-operative mean value: 37.5°) which was statistically significant (p<0.01). The IMA improved by an average of 5.96° from a pre-operative mean value of 15.4° (p<0.01). Neither osteonecrosis of the distal fragment nor perioperative fractures were noted during the follow-up. In keeping with our follow-up results, the Scarf osteotomy approach shows potential in the therapy of hallux valgus. PMID:21808668

Effect of various hallux valgus reconstruction on sesamoid location: a radiographic study.

PubMed

Huang, Eddie H; Charlton, Timothy P; Ajayi, Samuel; Thordarson, David B

2013-01-01

The correction of sesamoid subluxation is an important component of hallux valgus reconstruction with some surgeons feeling that the sesamoids can be pulled back under the first metatarsal head when imbricating the medial capsule during surgery. The purpose of this study was to radiographically assess the effect of an osteotomy on sesamoid location relative to the second metatarsal. This is a retrospective radiographic study review of 165 patients with hallux valgus treated with reconstructive osteotomies. Patients were included if they underwent a scarf or basilar osteotomy for hallux valgus but were excluded if they had inflammatory arthropathy or lesser metatarsal osteotomy. A modified McBride soft tissue procedure was performed in conjunction with the basilar and scarf osteotomies. Each patient's preoperative and postoperative radiographs were evaluated for hallux valgus angle, intermetatarsal 1-2 angle, tibial sesamoid classification, and lateral sesamoid location relative to the second metatarsal. The greatest correction of both hallux valgus and intermetatrsal 1-2 angle was achieved in basilar osteotomies (20.6 degrees and 9.7 degrees, respectively), then scarf osteotomies (14.4 degrees and 8.7 degrees, respectively). Basilar and scarf osteotomies both corrected medial sesamoid subluxation relative to the first metatarsal head an average of 2-3 classification stages. All osteotomies had minimal lateral sesamoid location change relative to the second metatarsal. The majority of sesamoid correction correlated with the intermetatarsal 1-2 correction. The concept that medial capsular plication pulls the sesamoids beneath the first metatarsal (ie, changes the location of the sesamoids relative to the second metatarsal) was not supported by our results. Level III, retrospective case series.

[Total knee arthroplasty by lateral parapatellar approach for valgus knee].

PubMed

Zhou, Dian-ge; Zhang, Bin; Kou, Bo-long; Lü, Hou-shan

2007-07-17

To investigate the effect of lateral parapatellar approach in total knee arthroplasty (TKA) of valgus knee. Lateral parapatellar approach of total knee arthroplasty was applied in 8 patients (10 knees) with severe valgus osteoarthritis knee (bilateral in 2 cases and unilateral in 6 cases), with the valgus angle > 15 degrees , 1 male (1 knee) and 7 females (9 knee), aged 68.2 (58 - 79), 7 cases (9 knees) being of the Krackow type I and 1 case (1 knee) of the Krackow type I, I. After incision of the skin through lateral knee, ilio-tibial band was prolonged by apple pie arthroplasty. The joint capsule was cut open laterally 2 - 4 cm from the para-patellar edge. Soft tissue balance was performed by releasing I - T band in Gerdy tubercle, lateral collateral ligament and poster-lateral capsule from the femur and tibial side. Valgus angle of distal femur cutting were five degree. Whiteside line and trans-epicondylar line were used as AP rotational cutting reference. All patellar of the group were resurfaced. Capsule closure is completed with the knee flexed. The expanded deep lateral soft tissue sleeve (coronal Z-plasty) is sutured with the medial retinaculum sleeve (superficial layer). Follow-up was conducted for 19.6 months (1 - 51 months). Seven cases (9 knees) were replaced by posterior stabilized cemented prostheses (TC-Dynamic, PLUS), one case (1 knee) was replaced by RT prosthesis (RT-PLUS(TM) Solution, PLUS). After operation, the valgus deformity of all patients was corrected and all patients could walk 100 m with or without the help of walking holders. The average range of motion (ROM) was improved from the pre-operative. 95.6 degrees (85 degrees - 110 degrees ) to the post-operative 117.1 degrees (100 degrees - 125 degrees ). The average femorotibial angle (FTA) was corrected from the pre-operative. 27.6 degrees (20 degrees - 40 degrees ) to the post-operative 6.8 degrees (5 degrees - 9 degrees ). The Knee Score System (KSS) score and functional score were

History of surgical treatments for hallux valgus.

PubMed

Galois, Laurent

2018-05-31

In the nineteenth century, the prevalent understanding of the hallux valgus was that it was purely an enlargement of the soft tissue, first metatarsal head, or both, most commonly caused by ill-fitting footwear. Thus, treatment had varying results, with controversy over whether to remove the overlying bursa alone or in combination with an exostectomy of the medial head. Since 1871, when the surgical technique was first described, many surgical treatments for the correction of hallux valgus have been proposed. A number of these techniques have come into fashion, and others have fallen into oblivion. Progress in biomechanical knowledge, and improvements in materials and supports have allowed new techniques to be developed over the years. We have developed techniques that sacrifice the metatarsophalangeal joint (arthrodesis, arthroplasties), as well as conservative procedures, and one can distinguish those which only involve the soft tissues from those that are linked with a first ray osteotomy.

Primary and coupled motions of the native knee in response to applied varus and valgus load.

PubMed

Gladnick, Brian P; Boorman-Padgett, James; Stone, Kyle; Kent, Robert N; Cross, Michael B; Mayman, David J; Pearle, Andrew D; Imhauser, Carl W

2016-06-01

Knowledge of the complex kinematics of the native knee is a prerequisite for a successful reconstructive procedure. The aim of this study is to describe the primary and coupled motions of the native knee throughout the range of knee flexion, in response to applied varus and valgus loads. Twenty fresh-frozen cadaver knees were affixed to a six degree of freedom robotic arm with a universal force-moment sensor, and loaded with a 4Nm moment in varus and valgus at 0, 15, 30, 45, and 90° of knee flexion. The resulting tibiofemoral angulation, displacement, and rotation were recorded. For each parameter investigated, the knee joint demonstrated more laxity at higher flexion angles. Varus angulation increased progressively from zero (2.0° varus) to 90 (5.2° varus) degrees of knee flexion (p<0.001). Valgus angulation also increased progressively, from zero (1.5° valgus) to 90 (3.9° valgus) degrees of knee flexion (p<0.001). At all flexion angles, the magnitude of tibiofemoral angle deviation was larger with varus than with valgus loading (p<0.05). We conclude that the native knee exhibits small increases in coronal plane laxity as the flexion angle increases, and that the knee has generally more laxity under varus load than with valgus load throughout the Range of Motion (ROM). Larger differences in laxity of more than 2 to 3°, or peak laxity specifically during the range of mid-flexion, were not found in our cadaver model and are not likely to represent normal coronal plane kinematics. Level V, biomechanical cadaveric study. Copyright © 2016 Elsevier B.V. All rights reserved.

Hallux valgus in a historical French population: paleopathological study of 605 first metatarsal bones.

PubMed

Mafart, Bertrand

2007-03-01

To estimate the prevalence of hallux valgus in a historical population in France, to identify associated skeletal abnormalities, and to look for an influence of footwear changes through time. We studied the 605 first metatarsals found in the necropolis of the Notre-Dame-du-Bourg cathedral in Digne in the Alpes-de-Hautes-Provence region of southern France. The necropolis contains remains from the 5th to the 17th century. Hallux valgus was identified only in individuals older than 30years at death, and its prevalence increased significantly with age. Exostosis at the medial and dorsal aspects of the head of the first metatarsal were common in advanced forms. The prevalence was comparable in males and females in the Middle Ages but was significantly higher in males in the 16th and 17th centuries, whereas in contemporary populations females are selectively affected. The increase in the prevalence of hallux valgus over time suggests an influence of changes in footwear. The heeled shoes and boots made of stiff leather that men wore in premodern times probably promoted the development of hallux valgus. However, the prevalence of hallux valgus in women in western industrialized countries today is even higher than that in our historical population of older premodern individuals, suggesting an extremely deleterious effect of contemporary female footwear.

Increased Incidence and Severity of Postoperative Radiographic Hallux Valgus Interphalangeus With Surgical Correction of Hallux Valgus.

PubMed

Dixon, Alexis E; Lee, Lydia C; Charlton, Timothy P; Thordarson, David B

2015-08-01

A previous study has shown an increased radiographic prevalence and severity of hallux valgus interphalangeus (HVIP) after surgical correction of hallux valgus (HV) due to correction of pronation deformity. The purpose of this study was to evaluate the change in pre- and postoperative HVIP deformity with correction of HV with multiple radiographic parameters. A retrospective chart review identified all bunion surgeries performed at a single center from July 1, 2009, to September 30, 2012. Exclusion criteria included prior bony surgery to the first ray, inadequate films, nonadult bunion, Akin osteotomy, or surgical treatment other than bunion correction. Pre- and postoperative films were reviewed for 2 HV angular measurements and 5 HVIP measurements, which were compared. The angles measured were hallux valgus angle (HVA), first intermetatarsal angle (IMA), hallux interphalangeus angle (HIA), distal metatarsal articular angle (DMAA), proximal phalangeal articular angle (PPAA), proximal to distal phalangeal articular angle (PDPAA), and total distal deformity (TDD). Prevalence of HVIP was analyzed in pre- and postoperative radiographs. A 1-sided Student t test was used to compare continuous data, and a chi-square test was used to compare categorical data. Ninety-two feet in 82 patients were eligible. The average preoperative HV improved with surgery. Preoperative HVA improved from 27 to 11 degrees (P < .001). Preoperative IMA improved from 13.6 to 6.1 degrees (P < .001). HVIP worsened after surgery. Preoperative HIA increased from 7.2 to 13.2 degrees (P < .001). DMAA worsened from 7.3 to 9.2 degrees (P = .001). PPAA worsened from 3.2 to 6.2 degrees. PDPAA worsened from 6.7 to 8.2 degrees (P < .001). The TDD increased from 14.6 to 17.9 degrees (P < .001). The prevalence of HVIP pre- and postoperatively as defined by HIA increased from 26% to 79% (P < .001) and by PPAA from 12% to 46% (P < .001). Initial assessment of preoperative radiographs underestimated HVIP

Patient-Directed Valgus Stress Radiograph of the Knee: A New and Novel Technique.

PubMed

Mauerhan, David R; Cook, Kyle D; Botts, Tonia D; Williams, Sherita T

2016-01-01

The radiographic investigation of patients with medial-compartment osteoarthritis of the knee is a critical element in the decision-making process of determining whether the patient is a candidate for unicompartmental or total knee arthroplasty. A valgus stress radiograph of the affected knee is an essential part of this radiographic investigation. Historically, this has been performed with manual stress applied by the surgeon or the radiologic technologist; thus, this examination requires 2 individuals to complete. In addition to being inefficient, 1 individual is exposed to radiation, which can be undesirable over many exposures and in a long career. For these reasons, we instituted a quality improvement project to develop a method of obtaining the valgus stress view with 1 technologist that would obviate these concerns. Of 78 examinations performed, 5 studies did not show complete correction of the varus deformity. Of these, 3 showed complete correction on a manual valgus stress radiograph, and 2 did not. Three patients displayed collapse of the lateral compartment, indicating a nonfunctional lateral compartment. The remaining 70 patients had identical radiographic results with both the manual and patient-directed valgus stress.

Radiographic Shape of Foot With Second Metatarsophalangeal Joint Dislocation Associated With Hallux Valgus.

PubMed

Kokubo, Tetsuro; Hashimoto, Takeshi; Suda, Yasunori; Waseda, Akeo; Ikezawa, Hiroko

2017-12-01

Second metatarsophalangeal (MTP) joint dislocation is associated with hallux valgus, and the treatment of complete dislocation can be difficult. The purpose of this study was to radiographically clarify the characteristic foot shape in the presence of second MTP joint dislocation. Weight-bearing foot radiographs of the 268 patients (358 feet) with hallux valgus were examined. They were divided into 2 groups: those with second MTP joint dislocation (study group = 179 feet) and those without dislocation (control group = 179 feet). Parameters measured included the hallux valgus angle (HVA), first-second intermetatarsal angle (IMA), second MTP joint angle, hallux interphalangeal angle (IPA), second metatarsal protrusion distance (MPD), metatarsus adductus angle (MAA), and the second metatarsal declination angle (2MDA). Furthermore, the dislocation group was divided into 3 subgroups according to second toe deviation direction: group M (medial type), group N (neutral type), and group L (lateral type). The IPA and the 2MDA were significantly greater in the study group than in the control group. By multiple comparison analysis, the IMA was greatest in group M and smallest in group L. The IPA was smaller and 2MDA greater in group N than in group L. The HVA and MAA in group L were greatest, and MPD in group L was smallest. The patients with second MTP joint dislocation associated with hallux valgus had greater hallux interphalangeal joint varus and a second metatarsal more inclined than with hallux valgus alone. The second toe deviated in a different direction according to the foot shape. Level III, retrospective comparative study.

Carpal valgus in llamas and alpacas: Retrospective evaluation of patient characteristics, radiographic features and outcomes following surgical treatment

PubMed Central

Hunter, Barbara; Duesterdieck-Zellmer, Katja F.; Huber, Michael J.; Parker, Jill E.; Semevolos, Stacy A.

2014-01-01

This study evaluated outcomes of surgical treatment for carpal valgus in New World camelids and correlated successful outcome (absence of carpal valgus determined by a veterinarian) with patient characteristics and radiographic features. Univariable and multivariable analyses of retrospective case data in 19 camelids (33 limbs) treated for carpal valgus between 1987 and 2010 revealed that procedures incorporating a distal radial transphyseal bridge were more likely (P = 0.03) to result in success after a single surgical procedure. A greater degree of angulation (> 19°, P = 0.02) and younger age at surgery (< 4 months, P = 0.03) were associated with unsuccessful outcome. Overall, 74% of limbs straightened, 15% overcorrected, and 11% had persistent valgus following surgical intervention. To straighten, 22% of limbs required multiple procedures, not including implant removal. According to owners, valgus returned following implant removal in 4 limbs that had straightened after surgery. PMID:25477542

Bosch osteotomy and scarf osteotomy for hallux valgus correction.

PubMed

Maffulli, Nicola; Longo, Umile Giuseppe; Oliva, Francesco; Denaro, Vincenzo; Coppola, Cristiano

2009-10-01

Minimally invasive distal metatarsal osteotomies are becoming broadly accepted for correction of hallux valgus. We compared the duration of surgery, the length of hospital stay, the American Orthopaedic Foot and Ankle Society (AOFAS) score, and the Foot and Ankle Outcome Score (FAOS) in 36 patients who underwent a minimal incision subcapital osteotomy of the first metatarsal with 36 matched patients who had hallux valgus corrected by a scarf technique. The minimum follow-up was 2.1 years (mean, 2.5 years; range, 2.1-3.2 years). Patients having the osteotomy had similar AOFAS and FAOS scores with less operating time and earlier discharge. Less operative time may benefit the patients, and earlier discharge has financial implications for the hospital.

Effects of flexor-pronator muscle loading on valgus stability of the elbow with an intact, stretched, and resected medial ulnar collateral ligament.

PubMed

Udall, John H; Fitzpatrick, Michael J; McGarry, Michelle H; Leba, Thu-Ba; Lee, Thay Q

2009-01-01

The medial ulnar collateral ligament (MUCL) is an important passive stabilizer to the valgus stresses that athletes experience during overhead throwing motion. However, the role of the flexor-pronator muscles as active stabilizers to valgus stress is not well defined in the literature. The objectives of this study were to quantify the relative contribution of the individual flexor-pronator muscles to valgus stability of the elbow and how this relationship was affected by ligament status. A custom elbow testing system and Microscribe 3DLX were used for biomechanical testing. Flexor-pronator muscles were loaded to simulate contraction, and the valgus angle of the elbow was measured in eight cadaveric specimens at 30 degrees , 60 degrees , and 90 degrees of elbow flexion with 3 different valgus torques applied to the forearm. Loads based on muscle cross-sectional area were applied to the flexor carpi ulnaris (FCU), flexor digitorum superficialis (FDS), and pronator teres (PT). The effect of each muscle was evaluated by unloading the individual muscle while the other 2 remained loaded, resulting in 5 loading conditions: no muscles loaded, all muscles loaded, unloaded FCU, unloaded FDS, and unloaded PT. Valgus angle was measured for 3 MUCL ligament conditions: intact, stretched, and cut. The effect of muscle loading on valgus angle was similar for each ligament condition. Loading the flexor-pronator muscles significantly decreased valgus angle of the elbow in all testing conditions (P < .01). Unloading the FDS significantly increased valgus angle compared to all muscles loaded in all testing conditions (P < .016). Unloading the FCU and PT significantly increased valgus angle in less than half of the testing conditions. The FDS, PT, and FCU are all active stabilizers of the elbow to valgus stress. The FDS is the biggest contributor amongst the flexor-pronator muscles.

Distal chevron osteotomy with distal soft tissue procedure for moderate to severe hallux valgus deformity.

PubMed

Bai, Long Bin; Lee, Keun Bae; Seo, Chang Young; Song, Eun Kyoo; Yoon, Taek Rim

2010-08-01

Distal chevron osteotomy has been widely employed to treat mild to moderate hallux valgus deformity. The purpose of the present study was to evaluate the outcomes of distal chevron osteotomy with a distal soft tissue procedure for the correction of moderate to severe hallux valgus. We reviewed 76 patients (86 feet) that underwent distal chevron osteotomy with a distal soft tissue procedure for symptomatic moderate to severe hallux valgus deformity. At a mean followup of 31 months, all patients were evaluated using subjective, objective and radiographic measurements. Ninety-four percent of the patients were very satisfied or satisfied. Average AOFAS score improved from 54.7 points preoperatively to 92.9 at final followup. Average hallux valgus angle changed from 36.2 degrees preoperatively to 12.4 degrees at final followup, and average first-second intermetatarsal angle changed from 17.1 to 7.3 degrees. Average tibial sesamoid position changed from 2.4 preoperatively to 1.2 at final followup. Dorsal angulation of the head was observed in two feet, and plantaflexion of the head in four feet. There were no cases of avascular necrosis of the metatarsal head. Our results indicate that distal chevron osteotomy with a distal soft tissue procedure provides an effective and reliable means of correcting moderate to severe hallux valgus deformity, and that it does so with high levels of patient satisfaction and low incidence of complications.

[A special soft tissue procedure for treatment of hallux valgus].

PubMed

Waizy, H; Stukenborg-Colsman, C; Abbara-Czardybon, M; Emmerich, J; Windhagen, H; Frank, D

2011-02-01

Maintaining the corrected position of the first metatasophalangeal axis. Reducing postoperative stiffness by forgoing a medial capsular shift. Hallux valgus deformities or recurrent hallux valgus deformities. Existing osteoarthritis, joint stiffness, large bone defects, osteonecrosis. General medical contraindications to surgical interventions and anesthesiological procedures. Operation under regional anesthesia (foot block) or general anesthesia. Tourniquet. Longitudinal skin incision medial over the pseudexostosis of the first metatarsal bone. Preparing the tendon of the Musculus abductor hallucis. Detaching the tendon from the capsule. Incision of the joint capsule with protection of the extensor hallucis longus tendon and the dorsal neurovascular bundle in an L-wise manner. Osteotomy of the first metatarsal bone. Lax sutures of the capsule in correct position and reattachment of the Musculus abductor hallucis tendon shifted toward distal and dorsal, regarding the rotation of the hallux. Postoperative elevation of the operated foot. Analgesia with nonsteroidal antiinflammatory drugs. Postoperative weight-bearing according to the osteotomy. Passive mobilization of the metatarsophalangeal joint. Dressing for 4 weeks postoperatively in the corrected position. Radiologic control after 6 weeks. Hallux valgus orthosis at night and a toe spreader for a further 6 weeks. A total of 30 isolated hallux valgus deformities with a mean preoperative intermetatarsal (IMA) angle of 12.9° (range 11-15°) were operated with a chevron osteotomy. The mean follow-up was 14.4 (range 8-17) months. The mean dorsiflexion at the last follow-up was 44° (range 20-60°). Only 2 patients had a dorsiflexion <40°. The mean reduction of the IM angle was 5.6° (range 3-7°). One patient required wound revision. There was no infection or avascular necrosis of the metatarsal head observed in the patients. At follow-up, 20 (67%) patients were completely satisfied, 9 (30%) satisfied, and 1 (3

Equivalent correction in scarf and chevron osteotomy in moderate and severe hallux valgus: a randomized controlled trial.

PubMed

Deenik, Axel; van Mameren, Henk; de Visser, Enrico; de Waal Malefijt, Maarten; Draijer, Frits; de Bie, Rob

2008-12-01

Chevron osteotomy is a widely accepted osteotomy for correction of hallux valgus.(18) Algorithms were developed to overcome the limitations of distal osteotomies. Scarf osteotomy has become popular as a versatile procedure that should be able to correct most cases of acquired hallux valgus. The purpose of this study was to evaluate whether patients with moderate or severe hallux valgus have better correction with a scarf osteotomy as compared to chevron osteotomy. After informed consent, 136 feet in 115 patients were randomized to 66 scarf and 70 chevron osteotomies. Deformities of patients were classified as mild, moderate and severe according to IMA, and both groups were compared with independent t-tests. The results were measured using radiographic HVA, IMA and DMAA measurements. There were no statistical differences in HVA, IMA and DMAA between scarf and chevron osteotomy in mild to moderate hallux valgus. In severe hallux valgus, chevron osteotomy corrected HVA better than scarf osteotomy, although this group consisted of twelve patients only. Five patients in the chevron group and seven in the scarf group developed recurrent subluxation of the metatarsophalangeal joint. In patients with moderate and severe hallux valgus, the results of chevron osteotomy were at least as effective as a scarf osteotomy. Recurrent subluxation of the first metatatarsophalangeal joint was the main cause for insufficient correction. We favor the chevron osteotomy because it is less invasive, without sacrificing correction of HVA and IMA.

Impaired Varus-Valgus Proprioception and Neuromuscular Stabilization in Medial Knee Osteoarthritis

PubMed Central

Chang, Alison H.; Lee, Song Joo; Zhao, Heng; Ren, Yupeng; Zhang, Li-Qun

2014-01-01

Impaired proprioception and poor muscular stabilization in the frontal plane may lead to knee instability during functional activities, a common complaint in persons with knee osteoarthritis (KOA). Understanding these frontal plane neuromechanical properties in KOA will help elucidate the factors contributing to knee instability and aid in the development of targeted intervention strategies. The study objectives were to compare knee varus-valgus proprioception, isometric muscle strength, and active muscular contribution to stability between persons with medial KOA and healthy controls. We evaluated knee frontal plane neuromechanical parameters in 14 participants with medial KOA and 14 age- and gender-matched controls, using a joint driving device (JDD) with a customized motor and a 6-axis force sensor. Analysis of covariance with BMI as a covariate was used to test the differences in varus-valgus neuromechanical parameters between these two groups. The KOA group had impaired varus proprioception acuity (1.08 ± 0.59° vs. 0.69 ± 0.49°, p < 0.05), decreased normalized varus muscle strength (1.31 ± 0.75% vs. 1.79 ± 0.84% body weight, p < 0.05), a trend toward decreased valgus strength (1.29 ± 0.67% vs. 1.88 ± 0.99%, p = 0.054), and impaired ability to actively stabilize the knee in the frontal plane during external perturbation (4.67 ± 2.86 vs. 8.26 ± 5.95 Nm/degree, p < 0.05). The knee frontal plane sensorimotor control system is compromised in persons with medial KOA. Our findings suggest varus-valgus control deficits in both the afferent input (proprioceptive acuity) and muscular effectors (muscle strength and capacity to stabilize the joint). PMID:24321442

Use of the iPhone for radiographic evaluation of hallux valgus.

PubMed

Ege, Tolga; Kose, Ozkan; Koca, Kenan; Demiralp, Bahtiyar; Basbozkurt, Mustafa

2013-02-01

The purpose of this study was to compare the measurements made using a smartphone accelerometer and computerized measurements as a reference in a series of 32 hallux valgus patients. Two observers used an iPhone to measure the hallux valgus angle (HVA), intermetatarsal angle (IMA), and distal metatarsal articular angle (of anteroposterior foot radiographs in 32 patients with symptomatic hallux valgus on a computer screen. Digital angular measurements on the computer were set as the reference standard for analysis and comparison. The difference between computerized measurements and all iPhone measurements, and the difference between the first and second iPhone measurements for each observer were calculated. Inter- and intraobserver reliability of the smartphone measurement method was also tested. The variability of all measurements was similar for the iPhone and the computer-assisted techniques. The concordance between iPhone and computer-assisted angular measurements was excellent for the HVA, IMA, and DMAA. The maximum mean difference between the two techniques was 1.25 ± 1.02° for HVA, 0.92 ± 0.92° for IMA, and 1.10 ± 0.82° for DMAA. The interobserver reliability was excellent for HVA, IMA, and DMAA. The maximum mean difference between observers was 1.31 ± 0.89° for HVA, 0.90 ± 0.92° for IMA, and 0.78 ± 0.87° for DMAA. The intraobserver reliability was excellent for HVA, IMA, and DMAA. We conclude that the Hallux Angles software for the iPhone can be used for measurement of hallux valgus angles in clinical practice and even for research purposes. It is an accurate and reproducible method.

Preoperative radiological factors correlated to long-term recurrence of hallux valgus following distal chevron osteotomy.

PubMed

Pentikainen, Ilkka; Ojala, Risto; Ohtonen, Pasi; Piippo, Jouni; Leppilahti, Juhana

2014-12-01

The purpose of this article was to analyze the long-term radiologic results after distal chevron osteotomy for hallux valgus treatment and to determine the preoperative radiographic factors correlating with radiological recurrence of the deformity. The study included 100 consecutive patients who received distal chevron osteotomy for hallux valgus. The osteotomy included fixation with an absorbable pin in 50 cases, and no fixation in the other 50. For 6 weeks postoperatively, half of each group used a soft cast and half had a traditional elastic bandage. Weight-bearing radiographs were evaluated at 6 weeks, 6 months, 1 year, and a mean of 7.9 (range, 5.8-9.4) years postoperatively. At the final follow-up, radiological recurrence of hallux valgus deformity (HVA > 15 degrees) was observed in 56 feet (73%). Eleven feet (14%) had mild recurrence (HVA < 20 degrees), 44 (57%) moderate (20 degrees ≥ HVA < 40 degrees), and 1 (1%) severe (HVA ≥ 40 degrees). All recurrences were painless, and thus no revision surgery was required. Long-term hallux valgus recurrence was significantly affected by preoperative congruence, DMAA, sesamoid position, HVA, and I/II IMA. Radiological recurrence of hallux valgus deformity of 15 degrees or more was very common at long-term follow-up after distal chevron osteotomy. Preoperative congruence, DMAA, sesamoid position (LaPorta), HVA, and I/II IMA significantly affected recurrence. Level III, comparative case series. © The Author(s) 2014.

Evaluation of Hallux Valgus Correction With Versus Without Akin Proximal Phalanx Osteotomy.

PubMed

Shibuya, Naohiro; Thorud, Jakob C; Martin, Lanster R; Plemmons, Britton S; Jupiter, Daniel C

2016-01-01

Although the efficacy of Akin proximal phalanx closing wedge osteotomy as a sole procedure for correction of hallux valgus deformity is questionable, when used in combination with other osseous corrective procedures, the procedure has been believed to be efficacious. However, a limited number of comparative studies have confirmed the value of this additional procedure. We identified patients who had undergone osseous hallux valgus correction with first metatarsal osteotomy or first tarsometatarsal joint arthrodesis with (n = 73) and without (n = 81) Akin osteotomy and evaluated their radiographic measurements at 3 points (preoperatively, within 3 months after surgery, and ≥6 months after surgery). We found that those people who had undergone the Akin procedure tended to have a larger hallux abduction angle and a more laterally deviated tibial sesamoid position preoperatively. Although the radiographic correction of the deformity was promising immediately after corrective surgery with the Akin osteotomy, maintenance of the correction was questionable in our cohort. The value of additional Akin osteotomy for correction of hallux valgus deformity is uncertain. Published by Elsevier Inc.

Biomechanical effects of valgus knee bracing: a systematic review and meta-analysis.

PubMed

Moyer, R F; Birmingham, T B; Bryant, D M; Giffin, J R; Marriott, K A; Leitch, K M

2015-02-01

To review and synthesize the biomechanical effects of valgus knee bracing for patients with medial knee osteoarthritis (OA). Electronic databases were searched from their inception to May 2014. Two reviewers independently determined study eligibility, rated study quality and extracted data. Where possible, data were combined into meta-analyses and pooled estimates with 95% confidence intervals (CI) for standardized mean differences (SMD) were calculated. Thirty studies were included with 478 subjects tested while using a valgus knee brace. Various biomechanical methods suggested valgus braces can decrease direct measures of medial knee compressive force, indirect measures representing the mediolateral distribution of load across the knee, quadriceps/hamstring and quadriceps/gastrocnemius co-contraction ratios, and increase medial joint space during gait. Meta-analysis from 17 studies suggested a statistically significant decrease in the external knee adduction moment (KAM) during walking, with a moderate-to-high effect size (SMD = 0.61; 95% CI: 0.39, 0.83; P < 0.001). Meta-regression identified a near-significant association for the KAM effect size and duration of brace use only (β, -0.01; 95% CI: -0.03, 0.0001; P = 0.06); with longer durations of brace use associated with smaller treatment effects. Minor complications were commonly reported during brace use and included slipping, discomfort and poor fit, blisters and skin irritation. Systematic review and meta-analysis suggests valgus knee braces can alter knee joint loads through a combination of mechanisms, with moderate-to-high effect sizes in biomechanical outcomes. Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Modified Chevron osteotomy for hallux valgus deformity in female athletes. A 2-year follow-up study.

PubMed

Giotis, Dimitrios; Paschos, Nikolaos K; Zampeli, Franceska; Giannoulis, Dionisios; Gantsos, Apostolos; Mantellos, George

2016-09-01

Hallux valgus is an increasingly common deformity in young female athletes that constricts their daily athletic activities and influences foot cosmesis. The aim of this study was to evaluate the outcome of modified Chevron osteotomy for hallux valgus deformity in this specific population. Forty-two cases of modified Chevron osteotomies were carried out in 33 patients with mild to moderate hallux valgus deformity. Each participant was evaluated for AOFAS score, pain, range of motion, cosmetic and radiological outcome. Mean AOFAS score improved to 96.3 (p<0.001) while the mean range of motion of the metatarsophalangeal joint was maintained (p=0.138). The cosmetic result was excellent/good in 40 cases (95%). Mean metatarsophalangeal and intermetatarsal angles were decreased from 29.8° and 14.2° preoperatively to 12.2° and 8.1° postoperatively (p<0.001 and p<0.036), respectively. Modified Chevron osteotomy could offer substantial correction of hallux valgus deformity in young female athletes, with excellent clinical outcome. Copyright © 2015 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Preliminary Results and Learning Curve of the Minimally Invasive Chevron Akin Operation for Hallux Valgus.

PubMed

Jowett, Charlie R J; Bedi, Harvinder S

Minimally invasive surgery is increasing in popularity. It is relevant in hallux valgus surgery owing to the potential for reduced disruption of the soft tissues and improved wound healing. We present our results and assess the learning curve of the minimally invasive Chevron Akin operation for hallux valgus. A total of 120 consecutive feet underwent minimally invasive Chevron Akin for symptomatic hallux valgus, of which 14 were excluded. They were followed up for a mean of 25 (range 18 to 38) months. The patients were clinically assessed using the American Orthopaedic Foot and Ankle Society score. Complications and patient satisfaction were recorded. The radiographs were analyzed and measurements recorded for hallux valgus and intermetatarsal angle correction. The mean age of the patients undergoing surgery was 55 (range 25 to 81) years. Of the 78 patients, 76 (97.4%) were female and 2 (2.6%) were male; 28 (35.9%) cases were bilateral. The mean American Orthopaedic Foot and Ankle Society score improved from 56 (range 23 to 76) preoperatively to 87 (range 50 to 100) postoperatively (p < .001). The mean hallux valgus and intermetatarsal angles preoperatively were 29.7° (range 12° to 46°) and 14.0° (range 8° to 20°). The corresponding postoperative angles were 10.3° (range 0° to 25°) and 7.6° (range 3° to 15°; p < .001). The patients were satisfied with the results of surgery in 87% of cases (92 of 106). The incidence of reoperation was 14% (15 of 106). These are the only reported results for this technique. They display a steep associated learning curve. However, the results are promising, and the learning curve is comparable to that for open hallux valgus surgery. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

A modified Austin/chevron osteotomy for treatment of hallux valgus and hallux rigidus.

PubMed

Vasso, Michele; Del Regno, Chiara; D'Amelio, Antonio; Schiavone Panni, Alfredo

2016-03-01

The purpose of this brief paper is to present the preliminary results of a modified Austin/chevron osteotomy for treatment of hallux valgus and hallux rigidus. In this procedure, the dorsal arm of the osteotomy is performed orthogonal to the horizontal plane of the first metatarsal, the main advantage being that this allows much easier and more accurate multiplanar correction of first metatarsal deformities. From 2010 to 2013, 184 consecutive patients with symptomatic hallux valgus and 48 patients with hallux rigidus without severe metatarsophalangeal joint degeneration underwent such modified chevron osteotomy. Mean patient age was 54.9 (range 21-70) years, and mean follow-up duration was 41.7 (range 24-56) months. Ninety-three percent of patients were satisfied with the surgery. Mean American Orthopaedic Foot and Ankle Society (AOFAS) score improved from 56.6 preoperatively to 90.6 at last follow-up, and mean visual analog scale (VAS) pain score decreased from 5.7 preoperatively to 1.6 at final follow-up (p < 0.05). In patients treated for hallux valgus, mean hallux valgus angle decreased from 34.1° preoperatively to 6.2° at final follow-up, and mean intermetatarsal angle decreased from 18.5° preoperatively to 4.1° at final follow-up (p < 0.05). One patient developed postoperative transfer metatarsalgia, treated successfully with second-time percutaneous osteotomy of the minor metatarsals, whilst one patient had wound infection that resolved with systemic antibiotics. Level IV.

Relationships Between Varus–Valgus Laxity of the Severely Osteoarthritic Knee and Gait, Instability, Clinical Performance, and Function

PubMed Central

Freisinger, Gregory M.; Hutter, Erin E.; Lewis, Jacqueline; Granger, Jeffrey F.; Glassman, Andrew H.; Beal, Matthew D.; Pan, Xueliang; Schmitt, Laura C.; Siston, Robert A.; Chaudhari, Ajit M.W.

2017-01-01

Increased varus–valgus laxity has been reported in individuals with knee osteoarthritis (OA) compared to controls. However, the majority of previous investigations may not report truly passive joint laxity, as their tests have been performed on conscious participants who could be guarding against motion with muscle contraction during laxity evaluation. The purpose of this study was to investigate how a measure of passive knee laxity, recorded when the participant is under anesthesia, is related to varus–valgus excursion during gait, clinical measures of performance, perceived instability, and self-reported function in participants with severe knee OA. We assessed passive varus–valgus knee laxity in 29 participants (30 knees) with severe OA, as they underwent total knee arthroplasty (TKA). Participants also completed gait analysis, clinical assessment of performance (6-min walk (6 MW), stair climbing test (SCT), isometric knee strength), and self-reported measures of function (perceived instability, Knee injury, and Osteoarthritis Outcome Score (KOOS) a median of 18 days before the TKA procedure. We observed that greater passive varus–valgus laxity was associated with greater varus–valgus excursion during gait (R2 =0.34, p =0.002). Significant associations were also observed between greater laxity and greater isometric knee extension strength (p =0.014), farther 6 MW distance (p =0.033) and shorter SCT time (p =0.046). No relationship was observed between passive varus–valgus laxity and isometric knee flexion strength, perceived instability, or any KOOS subscale. The conflicting associations between laxity, frontal excursion during gait, and functional performance suggest a complex relationship between laxity and knee cartilage health, clinical performance, and self-reported function that merits further study. PMID:27664972

[Treatment of Hallux Valgus: Current Diagnostic Testing and Surgical Treatment Performed by German Foot and Ankle Surgeons].

PubMed

Arbab, Dariusch; Schneider, Lisa-Maria; Schnurr, Christoph; Bouillon, Bertil; Eysel, Peer; König, Dietmar Pierre

2018-04-01

Hallux valgus is one of the most prevalent foot deformities, and surgical treatment of Hallux valgus is one of the most common procedures in foot and ankle surgery. Diagnostic and treatment standards show large variation despite medical guidelines and national foot and ankle societies. The aim of this nationwide survey is a description of the current status of diagnostics and therapy of Hallux valgus in Germany. A nationwide online questionnaire survey was sent to two German foot and ankle societies. The participants were asked to answer a questionnaire of 53 questions with four subgroups (general, diagnostics, operation, preoperative management). Surgical treatment for three clinical cases demonstrating a mild, moderate and severe Hallux valgus deformity was inquired. 427 foot and ankle surgeons answered the questionnaire. 388 participants were certified foot and ankle surgeons from one or both foot and ankle societies. Medical history (78%), preoperative radiographs (100%) and preoperative radiographic management (78%) are of high or very high importance for surgical decision pathway. Outcome scores are used by less than 20% regularly. Open surgery is still the gold standard, whereas minimally invasive surgery is performed by only 7%. Our survey showed that diagnostic standards are met regularly. There is a wide variation in the type of procedures used to treat Hallux valgus deformity. TMT I arthrodesis is preferred in severe Hallux valgus, but also used to treat moderate and mild deformities. Minimally invasive surgery is still used by a minority of surgeons. It remains to be seen, to what extent minimally invasive surgery will be performed in the future. Georg Thieme Verlag KG Stuttgart · New York.

Long-term results of total knee arthroplasty for valgus knees: soft-tissue release technique and implant selection.

PubMed

Rajgopal, Ashok; Dahiya, Vivek; Vasdev, Attique; Kochhar, Hemanshu; Tyagi, Vipin

2011-04-01

To report long-term results of total knee arthroplasty (TKA) for valgus knees. 34 women and 19 men aged 39 to 84 (mean, 74) years with valgus knees underwent primary TKA by a senior surgeon. Of the 78 knees, 43, 29, and 6 had type-I, type-II, and type-III valgus deformities, respectively. A preliminary lateral soft-tissue release was performed, and the tibia and femur were prepared. The tight lateral structures were released using the pie-crusting technique. In 92% of the knees, cruciate-retaining implants were used. In knees with severe deformity and medial collateral ligament insufficiency, the posterior cruciate ligament was sacrificed and constrained implants were used. The Hospital for Special Surgery (HSS) knee score was assessed, as were tibiofemoral alignment, range of motion, stability, and evidence of loosening or osteolysis. Patients were followed up for 8 to 14 (mean, 10) years. All knees had a good patellar position and were clinically stable in both mediolateral and anteroposterior planes. No radiolucency was noted. The mean HSS knee score improved from 48 to 91 (p<0.001). The mean tibiofemoral alignment improved from valgus 20 to 5 degrees (p<0.001). The mean range of motion improved from 65 to 110 degrees (p<0.001). One patient developed a deep infection at year 4, and 2 had periprosthetic fractures at years 6 and 8. Adequate lateral soft-tissue release is the key to successful TKAs in valgus knees. The choice of implant depends on the severity of the valgus deformity and the extent of soft-tissue release needed to obtain a stable, balanced flexion and extension gap, in order to achieve minimal constraint with maximum stability.

The effect of repetitive baseball pitching on medial elbow joint space gapping associated with 2 elbow valgus stressors in high school baseball players.

PubMed

Hattori, Hiroshi; Akasaka, Kiyokazu; Otsudo, Takahiro; Hall, Toby; Amemiya, Katsuya; Mori, Yoshihisa

2018-04-01

To prevent elbow injury in baseball players, various methods have been used to measure medial elbow joint stability with valgus stress. However, no studies have investigated higher levels of elbow valgus stress. This study investigated medial elbow joint space gapping measured ultrasonically resulting from a 30 N valgus stress vs. gravitational valgus stress after a repetitive throwing task. The study included 25 high school baseball players. Each subject pitched 100 times. The ulnohumeral joint space was measured ultrasonographically, before pitching and after each successive block of 20 pitches, with gravity stress or 30 N valgus stress. Two-way repeated measures analysis of variance and Pearson correlation coefficient analysis were used. The 30 N valgus stress produced significantly greater ulnohumeral joint space gapping than gravity stress before pitching and at each successive 20-pitch block (P < .01). For the 2 stress methods, ulnohumeral joint space gapping increased significantly from baseline after 60 pitches (P < .01). Strong significant correlations were found between the 2 methods for measurement of medial elbow joint space gapping (r = 0.727-0.859, P < .01). Gravity stress and 30 N valgus stress may produce different effects with respect to medial elbow joint space gapping before pitching; however, 30 N valgus stress appears to induce greater mechanical stress, which may be preferable when assessing joint instability but also has the potential to be more aggressive. The present results may indicate that constraining factors to medial elbow joint valgus stress matched typical viscoelastic properties of cyclic creep. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Preoperative varus-valgus kinematic pattern throughout flexion persists more strongly after cruciate-retaining than after posterior-stabilized total knee arthroplasty.

PubMed

Hino, Kazunori; Oonishi, Yoshio; Kutsuna, Tatsuhiko; Watamori, Kunihiko; Iseki, Yasutake; Kiyomatsu, Hiroshi; Watanabe, Seiji; Miura, Hiromasa

2016-08-01

Restoration of normal knee kinematics is key to improving patient satisfaction and functional outcomes after total knee arthroplasty (TKA). However, the effect of preoperative varus-valgus kinematics due to knee osteoarthritis on the postoperative kinematics is unclear. The function of the knee ligament contributes to both knee stability and kinematics. The aim of this study was to evaluate changes in varus-valgus kinematics before and after TKA using a navigation system, in addition to comparing the pre- and postoperative changes in kinematic patterns between cruciate-retaining (CR)- and posterior-stabilized (PS)-TKAs. Forty knees treated with TKA were evaluated (CR-TKA 20; PS-TKA 20). Manual mild passive knee flexion was applied while moving the leg from full extension to flexion. The varus-valgus angle was automatically measured by a navigation system at every 10° of the flexion angle, and the kinematics were evaluated. Kinematic patterns throughout flexion can be classified into five types. The pre- and postoperative kinematic patterns were similar in 60% of patients who underwent CR-TKA, whereas they were similar in only 25% of those who underwent PS-TKA. The mean change in the size of the varus-valgus angle throughout flexion did not differ between CR-TKA and PS-TKA. However, the distribution of changes in the size of the varus-valgus angle differed between CR-TKA and PS-TKA. We obtained the following results: 1) some patterns of varus-valgus kinematics are noted under unloading conditions despite recovery of neutral alignment in extension and 2) the preoperative varus-valgus kinematic pattern persisted more strongly after CR-TKA than after PS-TKA. Copyright © 2015 Elsevier B.V. All rights reserved.

Bilateral Carpus Valgus with Cranial Bowing of the Distal Radius in a Foal

PubMed Central

Caron, J. P.; Fretz, P. B.; Pharr, J. W.; Bailey, J. V.

1986-01-01

Bilateral carpus valgus with concomitant outward rotation and cranial bowing of the distal radii was diagnosed in a crossbred foal. The foal was not lame on admission and showed no radiographic evidence of carpal bone abnormalities. Surgery was limited to the most severely affected leg, and consisted of a combination of growth promotion (periosteal transection and stripping) and temporary physeal retardation (transphyseal bridging) procedures. Correction of the valgus deformity was nearly complete in the operated limb and substantial improvement was observed in the cranial bowing and outward rotation in both limbs, five months postoperatively. ImagesFigure 1.Figure 2. PMID:17422668

Reliability and Validity of Observational Risk Screening in Evaluating Dynamic Knee Valgus

PubMed Central

Ekegren, Christina L.; Miller, William C.; Celebrini, Richard G.; Eng, Janice J.; MacIntyre, Donna L.

2012-01-01

Study Design Nonexperimental methodological study. Objectives To determine the interrater and intrarater reliability and validity of using observational risk screening guidelines to evaluate dynamic knee valgus. Background A deficiency in the neuromuscular control of the hip has been identified as a key risk factor for non-contact anterior cruciate ligament (ACL) injury in post pubescent females. This deficiency can manifest itself as a valgus knee alignment during tasks involving hip and knee flexion. There are currently no scientifically tested methods to screen for dynamic knee valgus in the clinic or on the field. Methods Three physiotherapists used observational risk screening guidelines to rate 40 adolescent female soccer players according to their risk of ACL injury. The rating was based on the amount of dynamic knee valgus observed on a drop jump landing. Ratings were evaluated for intrarater and interrater agreement using kappa coefficients. Sensitivity and specificity of ratings were evaluated by comparing observational ratings with measurements obtained using 3-dimensional (3D) motion analysis. Results Kappa coefficients for intrarater and interrater agreement ranged from 0.75 to 0.85, indicating that ratings were reasonably consistent over time and between physiotherapists. Sensitivity values were inadequate, ranging from 67–87%. This indicated that raters failed to detect up to a third of “truly high risk” individuals. Specificity values ranged from 60–72% which was considered adequate for the purposes of the screen. Conclusion Observational risk screening is a practical and cost-effective method of screening for ACL injury risk. Rater agreement and specificity were acceptable for this method but sensitivity was not. To detect a greater proportion of individuals at risk of ACL injury, coaches and clinicians should ensure that they include additional tests for other high risk characteristics in their screening protocols. PMID:19721212

Footwear modification following hallux valgus surgery: The all-or-none phenomenon.

PubMed

Robinson, Cal; Bhosale, Abhijit; Pillai, Anand

2016-06-26

To define footwear outcomes following hallux valgus surgery, focusing on patient return to comfortable and heeled footwear and patterns of post-operative footwear selection. Surgical intervention is indicated for symptomatic cases of hallux valgus unresponsive to conservative methods, with favourable reported outcomes. The return to various types of footwear post-operatively is reflective of the degree of correction achieved, and corresponds to patient satisfaction. Patients are expected to return to comfortable footwear post-operatively without significant residual symptoms. Many female patients will additionally attempt to return to high-heeled, narrow toe box shoes. However, minimal evidence exists to guide their expectations. Sixty-five female hallux valgus patients that had undergone primary surgery between 2011 and 2013 were retrospectively identified using our hospital surgical database. Patients were reviewed using a footwear-specific outcome questionnaire at a mean 18.5 mo follow-up. Eighty-six percent of patients were able to return to comfortable footwear post-operatively with minimal discomfort. Of those intending to resume wearing heeled footwear, 62% were able to do so, with 77% of these patients wearing these as or more frequently than pre-operatively. No significant difference was observed between pre- and post-operative heel size. Mean time to return to heeled footwear was 21.4 wk post-operation. Cosmetic outcomes were very high and did not adversely impact footwear selection. We report high rates of return to both comfortable and heeled shoes in female patients following primary hallux valgus surgery. We observed an "all-or-none phenomenon" where patients rejected a return to heeled footwear unless able to tolerate them at the same frequency and heel size as pre-operatively. A minority of patients were unable to return to comfortable footwear post-operatively, which had adverse ramifications on their quality-of-life. We recommend that the

Footwear modification following hallux valgus surgery: The all-or-none phenomenon

PubMed Central

Robinson, Cal; Bhosale, Abhijit; Pillai, Anand

2016-01-01

AIM: To define footwear outcomes following hallux valgus surgery, focusing on patient return to comfortable and heeled footwear and patterns of post-operative footwear selection. METHODS: Surgical intervention is indicated for symptomatic cases of hallux valgus unresponsive to conservative methods, with favourable reported outcomes. The return to various types of footwear post-operatively is reflective of the degree of correction achieved, and corresponds to patient satisfaction. Patients are expected to return to comfortable footwear post-operatively without significant residual symptoms. Many female patients will additionally attempt to return to high-heeled, narrow toe box shoes. However, minimal evidence exists to guide their expectations. Sixty-five female hallux valgus patients that had undergone primary surgery between 2011 and 2013 were retrospectively identified using our hospital surgical database. Patients were reviewed using a footwear-specific outcome questionnaire at a mean 18.5 mo follow-up. RESULTS: Eighty-six percent of patients were able to return to comfortable footwear post-operatively with minimal discomfort. Of those intending to resume wearing heeled footwear, 62% were able to do so, with 77% of these patients wearing these as or more frequently than pre-operatively. No significant difference was observed between pre- and post-operative heel size. Mean time to return to heeled footwear was 21.4 wk post-operation. Cosmetic outcomes were very high and did not adversely impact footwear selection. CONCLUSION: We report high rates of return to both comfortable and heeled shoes in female patients following primary hallux valgus surgery. We observed an “all-or-none phenomenon” where patients rejected a return to heeled footwear unless able to tolerate them at the same frequency and heel size as pre-operatively. A minority of patients were unable to return to comfortable footwear post-operatively, which had adverse ramifications on their quality

New modified technique of osteotomy for hallux valgus.

PubMed

Oh, I S; Kim, M K; Lee, S H

2004-12-01

To improve the technique of osteotomy for hallux valgus (bunion). 38 cases of a new modified osteotomy procedure for hallux valgus were performed for 22 patients (21 women and one man). During a 3-year (range, 2-5 years) follow-up, the patients underwent physical examination; and their American Orthopedic Foot and Ankle Society hallux-metatarso-phalangeal-interphalangeal scale scores and standard foot radiographic measurements were recorded. 20 of the 22 patients (38 cases) had no pain, achieved good cosmesis, and were completely satisfied with the results of the operation. The remaining 2 patients had occasional mild discomfort. The mean hallux-metatarso-phalangeal-interphalangeal scale score was 93 points (range, 78-100 points). The mean preoperative and postoperative metatarsophalangeal angles were 34 degrees and 11 degrees, respectively. The mean postoperative reduction of the intermetatarsal angle and metatarsophalangeal angle were 6 degrees and 23 degrees, respectively. The new technique of osteotomy achieved even greater stability and accurate correction of the deformity in our 38 cases. Furthermore, it was more effective than conventional 'chevron' osteotomy in terms of correction of the deformity. Therefore, it should be used more widely.

Impact of Podiatry Resident Experience Level in Hallux Valgus Surgery on Postoperative Outcomes

PubMed Central

Fleischer, Adam E.; Yorath, Martin C.; Joseph, Robert; Baron, Adam; Nordquist, Thomas; Moore, Braden; Robinson, Richmond; Reilly, Charles

2018-01-01

Background Despite modern advancements in transosseous fixation and operative technique, hallux valgus (i.e., bunion) surgery is still associated with a higher than usual amount of patient dissatisfaction, and is generally recognized as a complex and nuanced procedure requiring precise osseous and capsulotendon balancing. It stands to reason then that familiarity and skill level of trainee surgeons might impact surgical outcomes in this surgery. The aim of this study was to determine whether podiatry resident experience level influences mid-term outcomes in hallux valgus surgery. Methods Consecutive adults who underwent isolated hallux valgus surgery via distal metatarsal osteotomy at a single US metropolitan teaching hospital from January 2004 to January 2009 were contacted and asked to complete a validated outcome measure of foot health (Manchester-Oxford Foot Questionnaire) regarding their operated foot. Resident experience level was quantified using the surgical logs for the primary resident of record at the time of each case. Associations were assessed using simple, multiple and logistic regression analyses. Results A total of 102 adult patients (n=102 feet) agreed to participate with a mean age of 46.8 (SD 13.1 years, range 18-71) and average length of follow-up 6.2 years (SD 1.4, range 3.6-8.6). Level of trainee experience was not associated with postoperative outcomes in either the univariate (odds ratio 0.99 [95% CI 0.98-1.01], p = 0.827) or multivariate analyses (odds ratio 1.00 [95% CI 0.97-1.02], p = 0.907). Conclusions We conclude that podiatry resident level of experience in hallux valgus surgery does not contribute appreciably to postoperative clinical outcomes. PMID:24726058

Operative Treatment of Traumatic Hallux Valgus in Elite Athletes.

PubMed

Covell, D Jeff; Lareau, Craig R; Anderson, Robert B

2017-06-01

Traumatic hallux valgus is an increasingly common injury in the athletic population and represents a unique variant of turf toe. Failure to appropriately recognize and treat these injuries can lead to continued pain, decreased performance, progressive deformities, and ultimately degeneration of the hallux metatarsophalangeal joint. Limited literature currently exists to assist in the diagnosis, management, and operative treatment. Nineteen patients were reviewed in this series, including 12 National Football League, 6 college, and 1 high school player who was a college prospect. The average age for all patients at the time of surgery was 24.4 years (range, 19-33 years). Return to play and complications were evaluated. Overall, good operative results were obtained, with 74% of patients returning to their preinjury level of play at an average recovery time of 3.4 months. Traumatic hallux valgus is an increasingly common injury in the athletic population and represents a unique variant of turf toe. The impact of this injury cannot be overstated, as one-quarter of players were unable to return to play. Level IV, case series.

Plate fixation for proximal chevron osteotomy has greater risk for hallux valgus recurrence than Kirschner wire fixation.

PubMed

Park, Chul-Hyun; Ahn, Ji-Yong; Kim, Yu-Mi; Lee, Woo-Chun

2013-06-01

The purpose of this study was to compare the results of hallux valgus surgery between feet fixed with Kirschner wires and those fixed with a plate and screws. Between December 2008 and November 2009, 53 patients (62 feet) were treated with proximal chevron osteotomy and distal soft tissue procedure for symptomatic moderate to severe hallux valgus deformity. Thirty-four patients (41 feet) were stabilised with Kirschner wires (K-wire group) and 19 patients (21 feet) were stabilised with a locking plate (plate group). Clinical results were assessed using American Orthopaedic Foot and Ankle Society (AOFAS) score. Radiographic parameters were compared between these groups. Recurrence rate at the last follow-up was compared between the K-wire and plate groups. Mean AOFAS score was lower in the plate group, however, the difference between the groups was not statistically significant in AOFAS score at the last follow-up. Hallux valgus angle and intermetatarsal angle were significantly larger in the plate group at the last follow-up. Mean 1-2 metatarsal (MT) distance on immediately postoperative radiographs was significant larger in the plate group. Four (9.8 %) of the 41 feet in the K-wire group and 7 (33.3 %) of the 21 feet in the plate group showed hallux valgus recurrence at the last follow-up. The plate group had a significantly higher risk of recurrence than the K-wire group. Fixation of proximal chevron osteotomy using a plate and screws has a greater risk of hallux valgus recurrence than fixation using Kirschner wires.

[The retrocapital osteotomy ("chevron") for correction of splayfoot with hallux valgus].

PubMed

Gabel, Michael

2008-12-01

Surgical treatment of hallux valgus deformity with a distal osteotomy of the first metatarsal to address an increased intermetatarsal angle (IMA) I-II. This procedure is combined with a soft-tissue procedure at the first metatarsophalangeal joint: realignment of the first ray, lateral displacement of the first metatarsal head above the sesamoids, rebalancing of the soft tissues at the metatarsophalangeal joint. Pain and soft-tissue inflammation at the bunion, impaired function of the metatarsophalangeal joint, and lateral deviation of the hallux. IMA I-II valgus angle (HVA) 10 degrees. Symptomatic osteoarthritis of the first metatarsophalangeal joint, assessed clinically or radiographically. Acute inflammation of the forefoot, osteoporosis of the first metatarsal. Vascular disturbance. Cosmetic indication only. Relative: hypermobility of the first ray, valgus malalignment of the hindfoot, previous retrocapital osteotomy. Lateral soft-tissue release. Resection of the medial pseudoexostosis. V-shaped osteotomy of the distal metatarsal I. Exostosectomy. Lateral displacement of the first metatarsal head. Screw fixation. Realignment of the metatarsophalangeal joint by tightening of the medial soft tissues. Postoperative shoe with full weight bearing. Active exercises of the foot and hallux. Physiotherapy. Prophylaxis of deep vein thrombosis depending on the degree of mobility. Radiographic control after 6 weeks. Bandage or orthosis to maintain toe alignment. IMA I-II was reduced from 13.6 degrees preoperatively to 6.6 degrees postoperatively. HVA decreased from 29.8 degrees to 8.2 degrees postoperatively.

Parametric study of orthopedic insole of valgus foot on partial foot amputation.

PubMed

Guo, Jun-Chao; Wang, Li-Zhen; Chen, Wei; Du, Cheng-Fei; Mo, Zhong-Jun; Fan, Yu-Bo

2016-01-01

Orthopedic insole was important for partial foot amputation (PFA) to achieve foot balance and avoid foot deformity. The inapposite insole orthosis was thought to be one of the risk factors of reamputation for foot valgus patient, but biomechanical effects of internal tissues on valgus foot had not been clearly addressed. In this study, plantar pressure on heel and metatarsal regions of PFA was measured using F-Scan. The three-dimensional finite element (FE) model of partial foot evaluated different medial wedge angles (MWAs) (0.0°-10.0°) of orthopedic insole on valgus foot. The effect of orthopedic insole on the internal bone stress, the medial ligament tension of ankle, plantar fascia tension, and plantar pressure was investigated. Plantar pressure on medial heel region was about 2.5 times higher than that of lateral region based on the F-Scan measurements. FE-predicted results showed that the tension of medial ankle ligaments was the lowest, and the plantar pressure was redistributed around the heel, the first metatarsal, and the lateral longitudinal arch regions when MWA of orthopedic insole ranged from 7.5° to 8.0°. The plantar fascias maintained about 3.5% of the total load bearing on foot. However, the internal stresses from foot bones increased. The simulation in this study would provide the suggestion of guiding optimal design of orthopedic insole and therapeutic planning to pedorthist.

Radiographic angles in hallux valgus: Comparison between protractor and iPhone measurements.

PubMed

Meng, Hong-Zheng; Zhang, Wei-Lin; Li, Xiu-Cheng; Yang, Mao-Wei

2015-08-01

Radiographic angles are used to assess the severity of hallux valgus deformity, make preoperative plans, evaluate outcomes after surgery, and compare results between different methods. Traditionally, hallux valgus angle (HVA) has been measured by using a protractor and a marker pen with hardcopy radiographs. The main objective of this study is to compare HVA measurements performed using a smartphone and a traditional protractor. The secondary objective was to compare the time taken between those two methods. Six observers measured major HVA on 20 radiographs of hallux valgus deformity with both a standard protractor and an Apple iPhone. Four of the observers repeated the measurements at least a week after the original measurements. The mean absolute difference between pairs of protractor and smartphone measurements was 3.2°. The 95% confidence intervals for intra-observer variability were ±3.1° for the smartphone measurement and ±3.2° for the protractor method. The 95% confidence intervals for inter-observer variability were ±9.1° for the smartphone measurement and ±9.6° for the protractor measurement. We conclude that the smartphone is equivalent to the protractor for the accuracy of HVA measurement. But, the time taken in smartphone measurement was also reduced. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

First metatarsal length change after basilar closing wedge osteotomy for hallux valgus.

PubMed

Day, Thomas; Charlton, Timothy P; Thordarson, David B

2011-05-01

Hallux valgus deformities with large intermetatarsal angles require a more proximal metatarsal procedure to adequately correct the deformity. Due to the relative ease of a closing wedge osteotomy, this technique was adopted but with concern over first metatarsal shortening. In this study, we primarily evaluated angular correction and first metatarsal shortening. We evaluated 70 feet in 57 patients (average age, 54 years) with 52 female and five male. The average followup was 14 (range, 6 to 45) months. The charts were reviewed for the presence of metatarsalgia. Digital radiographic measurements were made for pre- and postoperative hallux valgus and intermetatarsal angles, dorsiflexion angle of the first metatarsal, and absolute and relative shortening of the first metatarsal. The average hallux valgus angle improved from 31 to 11 degrees (p < 0.0001) and intermetatarsal angle from 13.2 to 4.4 angles (p < 0.0001). The absolute shortening of the first metatarsal was 2.2 mm and relative shortening was 0.6 mm. There was 1.3 degrees of dorsiflexion on average. Excellent correction of the deformity with minimal dorsiflexion or new complaints of metatarsalgia was found with this technique. The new method of assessing the relative shortening found to be less than the absolute shortening, which we feel more accurately reflects the functional length of the first metatarsal.

Weightbearing CT in normal hindfoot alignment - Presence of a constitutional valgus?

PubMed

Burssens, A; Van Herzele, E; Leenders, T; Clockaerts, S; Buedts, K; Vandeputte, G; Victor, J

2017-02-16

The normal hindfoot angle is estimated between 2° and 6° of valgus in the general population. These results are solely based on clinical findings and plain radiographs. The purpose of this study is to assess the hindfoot alignment using weightbear CT. Forty-eight patients, mean age of 39.6±13.2 years, with clinical and radiological absence of hindfoot pathology were included. A weightbear CT was obtained and allowed to measure the anatomical tibia axis (TAx) and the hindfoot alignment (HA). The HA was firstly determined using the inferior point of the calcaneus (HA IC ). A density measurement of this area was subsequently performed to analyze if this point concurred with an increased ossification, indicating a higher load exposure. Secondly the HA was determined by dividing the calcaneus in the long axial view (HALA) and compared to the (HA IC ) to point out any possible differences attributed to the measurement method. Reliability was assessed using an intra class correlation coefficient (ICC). The mean HA IC equaled 0.79° of valgus±3.2 (ICC HA IC =0.73) with a mean TAx of 2.7° varus±2.1 (ICCTA=0.76). The HALA equaled 9.1° of valgus±4.8 (ICCHA LA=0.71) and differed significantly by a P<0.001 from the HA IC , which showed a more neutral alignment. Correlation between both was shown to be good by a Spearman's correlation coefficient of 0.74. The mean density of the inferior calcaneal area equaled 271.3±84.1 and was significantly higher than the regional calcaneal area (P<0.001). These results show a more neutral alignment of the hindfoot in this group of non-symptomatic feet as opposed to the generally accepted constitutional valgus. This could have repercussion on hindfoot position during fusion or in quantifying the correction of a malalignment. The inferior calcaneus point in this can be used during pre-operative planning of a hindfoot correction as an anatomical landmark due to its shown influence on load transfer. Copyright © 2017 European Foot and

Interventions for treating hallux valgus (abductovalgus) and bunions.

PubMed

Ferrari, J; Higgins, J P T; Prior, T D

2004-01-01

Hallux valgus is classified as an abnormal deviation of the great toe (hallux) towards the midline of the foot. To identify and evaluate the evidence from randomised trials of interventions used to correct hallux valgus. We searched the Cochrane Musculoskeletal Injuries Group trials register (2003/1), the Cochrane Central Register of Controlled Trials (The Cochrane Library issue 1, 2003), MEDLINE (January 1966 to March 2003) and EMBASE (1980 to January 2003). No language restrictions were applied. Hand searching of specific foot journals was also undertaken. Date of the most recent search: 31st March 2003. Randomised or quasi-randomised trials of both conservative and surgical treatments of hallux valgus. Excluded were studies comparing areas of surgery not specific to the control of the deformity such as use of anaesthetics or tourniquet placement. Methodological quality of trials which met the inclusion criteria was independently assessed by two reviewers. Data extraction was undertaken by two reviewers. The trials were grouped according to the interventions being compared, but the dissimilarity in the comparisons prevented pooling of results. The methodological quality of the 21 included trials was generally poor and trial sizes were small. Three trials involving 332 participants evaluated conservative treatments versus no treatment. There was no evidence of a difference in outcomes between treatment and no treatment. One good quality trial involving 140 participants compared surgery to conservative treatment. Evidence was shown of an improvement in all outcomes in patients receiving chevron osteotomy compared with those receiving orthoses. The same trial also compared surgery to no treatment in 140 participants. Evidence was shown of an improvement in all outcomes in patients receiving chevron osteotomy compared with those receiving no treatment. Two trials involving 133 people with hallux valgus compared Keller's arthroplasty with other surgical techniques. In

Comparison of the Modified McBride Procedure and the Distal Chevron Osteotomy for Mild to Moderate Hallux Valgus.

PubMed

Choi, Gi Won; Kim, Hak Jun; Kim, Taik Seon; Chun, Sung Kwang; Kim, Tae Wan; Lee, Yong In; Kim, Kyoung Ho

2016-01-01

Distal metatarsal osteotomy and the modified McBride procedure have each been used for the treatment of mild to moderate hallux valgus. However, few studies have compared the results of these 2 procedures for mild to moderate hallux valgus. The purpose of the present study was to compare the results of distal chevron osteotomy and the modified McBride procedure for treatment of mild to moderate hallux valgus according to the severity of the deformity. We analyzed the data from 45 patients (49.5%; 48 feet [49.0%]), who had undergone an isolated modified McBride procedure (McBride group), and 46 patients (50.5%; 50 feet [51.0%]), who had a distal chevron osteotomy (chevron group). We subdivided each group into those with mild and moderate deformity and compared the clinical and radiologic outcomes between the groups in relation to the severity of the deformity. The improvements in the American Orthopaedic Foot and Ankle Society scale score and the visual analog scale for pain were significantly better for the chevron group for both mild and moderate deformity. The chevron group experienced significantly greater correction in the hallux valgus angle and intermetatarsal angle for both mild and moderate deformity. The chevron group experienced a significantly greater decrease in the grade of sesamoid displacement for patients with moderate deformity. The McBride group had a greater risk of recurrence than did the chevron group for moderate deformity (odds ratio 14.00, 95% confidence interval 3.91 to 50.06, p < .001). The results of the present study have demonstrated the superiority of the distal chevron osteotomy over the modified McBride procedure for mild to moderate deformity. For patients with moderate deformity, the McBride group had a greater risk of hallux valgus recurrence than did the distal chevron group. Therefore, we recommend distal chevron osteotomy rather than a modified McBride procedure for the treatment of mild and moderate hallux valgus. Copyright

[Preemptive local anesthetic infiltration in hallux valgus one-day surgery].

PubMed

Gądek, Artur; Liszka, Henryk

2015-01-01

The surgical treatment of hallux valgus deformity is connected with significant postoperative pain. Spinal and general anesthesia as well as peripheral blocks are successfully used in foot surgery. The purpose of this study was to evaluate the influence of local anesthetic infiltration before hallux valgus one-day surgery on postoperative pain and the need for analgesics. 134 patients underwent chevron or miniinvasive Mitchell-Kramer osteotomy of the first distal metatarsal. After general anesthesia each patient randomly received an infiltration of 7ml of local anesthetic (4 ml of 0.25% bupivacaine and 3 ml of 2% lidocaine) or the same amount of normal saline 15 minutes before the skin incision. Both the patient and the surgeon were blinded. The patient was discharged after approximately 2 hours of observation. 2, 4, 8, 12, 16, 24 and 72 hours after the release of the tourniquet the level of pain was assessed by the visual analogue scale (VAS). Rescue analgesia, side effects and the use of painkillers were noted. Preemptive local anesthetic infiltration significantly decreased pain during the first 24 hours after the surgery. None of the patients from the injected group and 38 from the placebo group received 100 mg of ketoprofen intravenously for rescue analgesia in the first 2 hours after the release of the tourniquet. During the first 24 hours we noted significantly decreased use of 1000 mg of paracetamol and 100 mg mg of ketoprofen orally in the injected group. No systemic adverse effects were noted. One patient from placebo group had allergic rush after use of 100 mg ketoprofen. Preemptive local anesthetic infiltration in one-day hallux valgus surgery significantly decreases postoperative pain. It is safe, efficient and allows fast discharge.

Long-term Follow-up of a Randomized Controlled Trial Comparing Scarf to Chevron Osteotomy in Hallux Valgus Correction.

PubMed

Jeuken, Ralph M; Schotanus, Martijn G M; Kort, Nanne P; Deenik, Axel; Jong, Bob; Hendrickx, Roel P M

2016-07-01

Hallux valgus is one of the most common foot deformities. This long-term follow-up study compared the results of 2 widely used operative treatments for hallux valgus: the scarf and chevron osteotomy. Conventional weight bearing anteroposterior (AP) radiographs of the foot were made for evaluating the intermetatarsal angle and hallux valgus angle. For clinical evaluation, the American Orthopaedic Foot & Ankle Society (AOFAS) rating system for the hallux metatarsophalangeal-interphalangeal scale was used together with physical examination of the foot. These data were compared with the results from the original study. The Short Form 36 questionnaire, the Manchester-Oxford Foot Questionnaire (MOXFQ), and a general questionnaire including a visual analog scale (VAS) pain score were used for subjective evaluation. The primary outcome measures were the radiologic recurrence of hallux valgus and reoperation rate of the same toe. Secondary outcome measures were the results from the radiographs and subjective and clinical evaluation. The response rate was 76% at the follow-up of 14 years; in the chevron group, 37 feet were included compared with 36 feet in the scarf group. Twenty-eight feet in the chevron group and 27 in the scarf group developed recurrence of hallux valgus (P = .483). One patient in the scarf group had a reoperation of the same toe compared with none in the chevron group (P = .314). Current VAS pain scores and results from the SF-36, MOXFQ, and AOFAS did not significantly differ between groups. Both techniques showed similar results after 2 years of follow-up. At 14 years of follow-up, neither technique was superior in preventing recurrence. Level II, randomized controlled trial. © The Author(s) 2016.

The Valgus Inclination of the Tibial Component Increases the Risk of Medial Tibial Condylar Fractures in Unicompartmental Knee Arthroplasty.

PubMed

Inoue, Shinji; Akagi, Masao; Asada, Shigeki; Mori, Shigeshi; Zaima, Hironori; Hashida, Masahiko

2016-09-01

Medial tibial condylar fractures (MTCFs) are a rare but serious complication after unicompartmental knee arthroplasty. Although some surgical pitfalls have been reported for MTCFs, it is not clear whether the varus/valgus tibial inclination contributes to the risk of MTCFs. We constructed a 3-dimensional finite elemental method model of the tibia with a medial component and assessed stress concentrations by changing the inclination from 6° varus to 6° valgus. Subsequently, we repeated the same procedure adding extended sagittal bone cuts of 2° and 10° in the posterior tibial cortex. Furthermore, we calculated the bone volume that supported the tibial component, which is considered to affect stress distribution in the medial tibial condyle. Stress concentrations were observed on the medial tibial metaphyseal cortices and on the anterior and posterior tibial cortices in the corner of cut surfaces in all models; moreover, the maximum principal stresses on the posterior cortex were larger than those on the anterior cortex. The extended sagittal bone cuts in the posterior tibial cortex increased the stresses further at these 3 sites. In the models with a 10° extended sagittal bone cut, the maximum principal stress on the posterior cortex increased as the tibial inclination changed from 6° varus to 6° valgus. The bone volume decreased as the inclination changed from varus to valgus. In this finite element method, the risk of MTCFs increases with increasing valgus inclination of the tibial component and with increased extension of the sagittal cut in the posterior tibial cortex. Copyright © 2016 Elsevier Inc. All rights reserved.

Chevron osteotomy with lateral release and adductor tenotomy for hallux valgus.

PubMed

Potenza, Vito; Caterini, Roberto; Farsetti, Pasquale; Forconi, Fabrizio; Savarese, Eugenio; Nicoletti, Simone; Ippolito, Ernesto

2009-06-01

Distal chevron osteotomy is a procedure widely performed for the surgical treatment of painful hallux valgus. The risks and benefits of a lateral capsular release and adductor tenotomy combined with chevron osteotomy are still debated. The aim of our study was to report the clinical and radiographic outcomes of this combined procedure in mild and moderate incongruent bunion deformities, with a hallux valgus angle (HVA) up to 40 degrees and an intermetatarsal angle (IMA) up to 20 degrees. Forty-two patients (52 feet) who consecutively underwent chevron osteotomy combined with lateral release and adductor tenotomy were reviewed 24-36 months after surgery. The mean age of the patients was 53.5 (range, 43 to 64) years. All the deformities were mild to moderate, with a mean preoperative value of 28 degrees in the HVA (range, 16 degrees to 40 degrees) and of 13 degrees in the IMA (range, 9 degrees to 20 degrees). At followup, the AOFAS hallux score improved from an average of 46 to an average of 88. The HVA and IMA had an average postoperative decrease respectively of 12 degrees and 6 degrees; lateral sesamoid displacement decreased by a mean of 15%. In no case did we observe infection or nonunion of the osteotomy. In one case, painless avascular necrosis of the first metatarsal head developed. Our short-term results show that distal chevron osteotomy combined with lateral release and adductor tenotomy is a feasible surgical option to address mild to moderate hallux valgus deformity, even with an IM angle between 15 and 20 degrees. Clinical and radiographic outcomes are generally good and patient satisfaction is generally high.

No midterm benefit from low intensity pulsed ultrasound after chevron osteotomy for hallux valgus.

PubMed

Zacherl, Max; Gruber, Gerald; Radl, Roman; Rehak, Peter H; Windhager, Reinhard

2009-08-01

Chevron osteotomy is a widely accepted method for correction of symptomatic hallux valgus deformity. Full weight bearing in regular shoes is not recommended before 6 weeks after surgery. Low intensity pulsed ultrasound is known to stimulate bone formation leading to more stable callus and faster bony fusion. We performed a randomized, placebo-controlled, double-blinded study on 44 participants (52 feet) who underwent chevron osteotomy to evaluate the influence of daily transcutaneous low intensity pulsed ultrasound (LIPUS) treatment at the site of osteotomy. Follow-up at 6 weeks and 1 year included plain dorsoplantar radiographs, hallux-metatarsophalangeal-interphalangeal scale and a questionnaire on patient satisfaction. There was no statistical difference in any pre- or postoperative clinical features, patient satisfaction or radiographic measurements (hallux valgus angle, intermetatarsal angle, sesamoid index and metatarsal index) except for the first distal metatarsal articular angle (DMAA). The DMAA showed statistically significant (p = 0.046) relapse in the placebo group upon comparison of intraoperative radiographs after correction and fixation (5.2 degrees) and at the 6-week follow-up (10.6 degrees). Despite potential impact of LIPUS on bone formation, we found no evidence of an influence on outcome 6 weeks and 1 year after chevron osteotomy for correction of hallux valgus deformity.

Radiographic angles in hallux valgus: differences between measurements made manually and with a computerized program.

PubMed

Piqué-Vidal, Carlos; Maled-García, Ignaci; Arabi-Moreno, Juanjo; Vila, Joan

2006-03-01

The objective of this study was to compare angular measurements in the evaluation of hallux valgus deformities using a goniometer and a computerized program to assess degree of concordance between the two methods and determine the reliability of manual measurements. Angles measured included the hallux valgus angle (HVA), the intermetatarsal angle (IMA), the distal metatarsal articular angle (DMAA), and the proximal phalangeal articular angle (PPAA), also called the hallux valgus interphalangeus angle or interphalangeal angle. Measurements were made on preoperative weightbearing radiographs in 176 patients with symptomatic hallux valgus. Manual measurements were made with a goniometer by an orthopaedic surgeon. An independent experienced technician used digitized images to perform angular measurements with the Autocad software program (Autodesk Inc., San Rafael, CA). HVA values obtained with the two techniques were similar. However, significantly higher mean values were obtained with the Autocad for the IMA and PPAA measurements, and higher mean values were obtained for the DMAA measurement with the manual technique. Whereas differences were more or less randomly distributed for the HVA, in the remaining patients, measurements were clearly related to the measurement technique, i.e., for the DMAA, the manual technique had a tendency to show higher values, and for the IMA and PPAA the manual technique showed lower values than the computer. Correlations between both techniques for the different angular measurements were as follows: HVA, -0.179 (p = 0.018); DMMA, -0.294 (p < 0.001); PPAA, -0.876 (p < 0.001); and IMA, -0.661 (p < 0.001). The intraclass correlation coefficient (ICC) showed that the concordance between manual and Autocad angular measurements was excellent for the HVA (ICC = 0.89) and DMAA (ICC = 0.80) and very poor for the PPAA (ICC = 0.11) and IMA (ICC = 0.42). Angular measurements made on weightbearing radiographs with the Autocad in patients with hallux

Comparison of Clinical Outcomes of Scarf and Chevron Osteotomies and the McBride Procedure in the Treatment of Hallux Valgus Deformity

PubMed Central

Fakoor, Mohammad; Sarafan, Naser; Mohammadhoseini, Payam; Khorami, Mohsen; Arti, Hamidreza; Mosavi, SeyedShahnam; Aghaeeaghdam, Amir

2014-01-01

Background: Hallux valgus deformity is a common chronic problem with a reported prevalence of 28.4% and its chief complaint is pain. Thus far, different surgical procedures with their proposed indications have been introduced. This study compared three current procedures, namely the chevron and scarf osteotomies and the McBride procedure. Methods: This retrospective cohort was conducted at the Ahvaz University of Medical Sciences on 44 patients with moderate hallux valgus deformity from 2010 and 2013. All of the patients underwent one of the three procedures (chevron, scarf or McBride). Preoperative and follow up radiographies were evaluated in terms of hallux valgus and intermetatarsal angle correction. The Foot and Ankle Disability Index was filled out to assess the functional outcome and the Visual Analogue Scale was used to evaluate pain. Also, satisfaction, aesthetics and the rate of recurrence was evaluated. Results: Hallux valgus angle and intermetatarsal angle correction were significantly higher in scarf, but not in chevron and McBride. However, from amongst the three procedures, there was no significant difference in terms of the Foot and Ankle Disability Index score, aesthetics, satisfaction level, pain score and recurrence rate. Conclusions: Considering that scarf osteotomy had better results in this study, we think that scarf osteotomy can be considered as a first choice for the treatment of moderate hallux valgus deformity. PMID:25207310

Comparison of Clinical Outcomes of Scarf and Chevron Osteotomies and the McBride Procedure in the Treatment of Hallux Valgus Deformity.

PubMed

Fakoor, Mohammad; Sarafan, Naser; Mohammadhoseini, Payam; Khorami, Mohsen; Arti, Hamidreza; Mosavi, SeyedShahnam; Aghaeeaghdam, Amir

2014-03-01

Hallux valgus deformity is a common chronic problem with a reported prevalence of 28.4% and its chief complaint is pain. Thus far, different surgical procedures with their proposed indications have been introduced. This study compared three current procedures, namely the chevron and scarf osteotomies and the McBride procedure. This retrospective cohort was conducted at the Ahvaz University of Medical Sciences on 44 patients with moderate hallux valgus deformity from 2010 and 2013. All of the patients underwent one of the three procedures (chevron, scarf or McBride). Preoperative and follow up radiographies were evaluated in terms of hallux valgus and intermetatarsal angle correction. The Foot and Ankle Disability Index was filled out to assess the functional outcome and the Visual Analogue Scale was used to evaluate pain. Also, satisfaction, aesthetics and the rate of recurrence was evaluated. Hallux valgus angle and intermetatarsal angle correction were significantly higher in scarf, but not in chevron and McBride. However, from amongst the three procedures, there was no significant difference in terms of the Foot and Ankle Disability Index score, aesthetics, satisfaction level, pain score and recurrence rate. Considering that scarf osteotomy had better results in this study, we think that scarf osteotomy can be considered as a first choice for the treatment of moderate hallux valgus deformity.

Medial Elbow Joint Space Increases With Valgus Stress and Decreases When Cued to Perform A Maximal Grip Contraction.

PubMed

Pexa, Brett S; Ryan, Eric D; Myers, Joseph B

2018-04-01

Previous research indicates that the amount of valgus torque placed on the elbow joint during overhead throwing is higher than the medial ulnar collateral ligament (UCL) can tolerate. Wrist and finger flexor muscle activity is hypothesized to make up for this difference, and in vitro studies that simulated activity of upper extremity musculature, specifically the flexor digitorum superficialis and flexor carpi ulnaris, support this hypothesis. To assess the medial elbow joint space at rest, under valgus stress, and under valgus stress with finger and forearm flexor contraction by use of ultrasonography in vivo. Controlled laboratory study. Participants were 22 healthy males with no history of elbow dislocation or UCL injury (age, 21.25 ± 1.58 years; height, 1.80 ± 0.08 m; weight, 79.43 ± 18.50 kg). Medial elbow joint space was measured by use of ultrasonography during 3 separate conditions: at rest (unloaded), under valgus load (loaded), and with a maximal grip contraction under a valgus load (loaded-contracted) in both limbs. Participants lay supine with their arm abducted 90° and elbow flexed 30° with the forearm in full supination. A handgrip dynamometer was placed in the participants' hand to grip against during the contracted condition. Images were reduced in ImageJ to assess medial elbow joint space. A 2-way (condition × limb) repeated-measures analysis of variance and Cohen's d effect sizes were used to assess changes in medial elbow joint space. Post hoc testing was performed with a Bonferroni adjustment to assess changes within limb and condition. The medial elbow joint space was significantly larger in the loaded condition (4.91 ± 1.16 mm) compared with the unloaded condition (4.26 ± 1.23 mm, P < .001, d = 0.712) and the loaded-contracted condition (3.88 ± 0.94 mm, P < .001, d = 1.149). No significant change was found between the unloaded and loaded-contracted conditions ( P = .137). Medial elbow joint space increases under a valgus load and then

Tibial condylar valgus osteotomy (TCVO) for osteoarthritis of the knee: 5-year clinical and radiological results.

PubMed

Chiba, Ko; Yonekura, Akihiko; Miyamoto, Takashi; Osaki, Makoto; Chiba, Goji

2017-03-01

Tibial condylar valgus osteotomy (TCVO) is a type of opening-wedge high tibial osteotomy for advanced medial knee osteoarthritis (OA) with subluxated lateral joint. We report the concept, the current surgical technique with a locking plate, and the short-term clinical and radiological results of this procedure. 11 knees with medial OA and a widened lateral joint were treated by TCVO (KL stage III: 6, IV: 5). In this procedure, by the L-shaped osteotomy from the medial side of the proximal tibia to the intercondylar eminence and the valgus correction, lateralization of the mechanical axis and reduction of the subluxated lateral joint are obtained with early postoperative weight-bearing. Before, 6 months, 1, and 5 years after the operation, a visual analog scale (VAS), the Western Ontario and McMaster Universities Arthritis Index (WOMAC), alignment of the lower extremity, and congruency and stability of the femorotibial joint were investigated. The VAS improved from an average of 73 mm to 13 mm, and the total WOMAC score from 52 to 14 before to 5 years after the operation, respectively. The mechanical axis changed from 1 to 60%, and the FTA changed from 186° to 171°. The joint line convergence angle (JLCA) changed from 6° to 1°, and the angle difference of JLCA between varus and valgus stress improved from 8° to 4° after the procedure. Improvements in pain and activities of daily living were observed by TCVO along with valgus correction of the lower extremity and stabilization of the femorotibial joint.

Perioperative analgesia with a buprenorphine transdermal patch for hallux valgus surgery: a prospective, randomized, controlled study

PubMed Central

Xu, Can; Li, Mingqing; Wang, Chenggong; Li, Hui; Liu, Hua

2018-01-01

Purpose Hallux valgus surgery often results in significant postoperative pain. Adequate control of pain is essential for patient satisfaction and improves the outcome of the procedure. This study aimed to investigate the perioperative analgesic effect of a buprenorphine transdermal patch in patients who underwent hallux valgus surgery. Patients and methods A total of 90 patients were randomly divided into the following three groups based on the perioperative analgesic method: flurbiprofen axetil intravenous injection (Group F), oral celecoxib (Group C), and buprenorphine transdermal delivery system (BTDS) (Group BTDS). The pain status, degree of satisfaction, adverse effects, and administration of tramadol hydrochloride for uncontrolled pain were recorded on the night before surgery, postoperative day 1, postoperative day 2, and postoperative day 3. Results The BTDS could effectively control perioperative pain for patients undergoing hallux valgus surgery. The analgesic effect of the BTDS was better than that of oral celecoxib. In addition, statistically significant differences were not observed in the visual analog scale (VAS) scores, adverse effects, and rescue analgesia between the patients who received the BTDS and the patients who received the flurbiprofen axetil intravenous injection. However, the degree of patient satisfaction of the BTDS group was significantly higher (P<0.05) than that of the other two groups. Conclusion The BTDS (a preemptive analgesia regimen) could exert an analgesic effect during the perioperative period for patients who had received hallux valgus surgery, and this effect is beneficial for sustaining postoperative physiological and psychological states and promoting functional rehabilitation. PMID:29731664

WITHDRAWN: Interventions for treating hallux valgus (abductovalgus) and bunions.

PubMed

Ferrari, Jill; Higgins, Julian Pt; Prior, Trevor D

2009-04-15

Hallux valgus is classified as an abnormal deviation of the great toe (hallux) towards the midline of the foot. To identify and evaluate the evidence from randomised trials of interventions used to correct hallux valgus. We searched the Cochrane Bone, Joint and Muscle Trauama Group trials register (2003/1), the Cochrane Central Register of Controlled Trials (The Cochrane Library issue 1, 2003), MEDLINE (January 1966 to March 2003) and EMBASE (1980 to January 2003). No language restrictions were applied. Hand searching of specific foot journals was also undertaken.Date of the most recent search: 31st March 2003. Randomised or quasi-randomised trials of both conservative and surgical treatments of hallux valgus. Excluded were studies comparing areas of surgery not specific to the control of the deformity such as use of anaesthetics or tourniquet placement. Methodological quality of trials which met the inclusion criteria was independently assessed by two reviewers. Data extraction was undertaken by two reviewers. The trials were grouped according to the interventions being compared, but the dissimilarity in the comparisons prevented pooling of results. The methodological quality of the 21 included trials was generally poor and trial sizes were small.Three trials involving 332 participants evaluated conservative treatments versus no treatment. There was no evidence of a difference in outcomes between treatment and no treatment.One good quality trial involving 140 participants compared surgery to conservative treatment. Evidence was shown of an improvement in all outcomes in patients receiving chevron osteotomy compared with those receiving orthoses. The same trial also compared surgery to no treatment in 140 participants. Evidence was shown of an improvement in all outcomes in patients receiving chevron osteotomy compared with those receiving no treatment.Two trials involving 133 people with hallux valgus compared Keller's arthroplasty with other surgical techniques

Effects of foot rotation positions on knee valgus during single-leg drop landing: Implications for ACL injury risk reduction.

PubMed

Teng, P S P; Kong, P W; Leong, K F

2017-06-01

Non-contact anterior cruciate ligament (ACL) injuries commonly occur when athletes land in high risk positions such as knee valgus. The position of the foot at landing may influence the transmission of forces from the ankle to the knee. Using an experimental approach to manipulate foot rotation positions, this study aimed to provide new insights on how knee valgus during single-leg landing may be influenced by foot positions. Eleven male recreational basketball players performed single-leg drop landings from a 30-cm high platform in three foot rotation positions (toe-in, toe-forward and toe-out) at initial contact. A motion capture system and a force plate were used to measure lower extremity kinematics and kinetics. Knee valgus angles at initial contact (KVA) and maximum knee valgus moments (KVM), which were known risk factors associated with ACL injury, were measured. A one-way repeated measures Analysis of Variance was conducted (α=0.05) to compare among the three foot positions. Foot rotation positions were found to have a significant effect on KVA (p<0.001, η 2 =0.66) but the difference between conditions (about 1°) was small and not clinically meaningful. There was a significant effect of foot position on KVM (p<0.001, η 2 =0.55), with increased moment observed in the toe-out position as compared to toe-forward (p=0.012) or toe-in positions (p=0.002). When landing with one leg, athletes should avoid extreme toe-out foot rotation positions to minimise undesirable knee valgus loading associated with non-contact ACL injury risks. Copyright © 2017 Elsevier B.V. All rights reserved.

Dynamic knee valgus alignment influences impact attenuation in the lower extremity during the deceleration phase of a single-leg landing.

PubMed

Tamura, Akihiro; Akasaka, Kiyokazu; Otsudo, Takahiro; Shiozawa, Jyunya; Toda, Yuka; Yamada, Kaori

2017-01-01

Dynamic knee valgus during landings is associated with an increased risk of non-contact anterior cruciate ligament (ACL) injury. In addition, the impact on the body during landings must be attenuated in the lower extremity joints. The purpose of this study was to investigate landing biomechanics during landing with dynamic knee valgus by measuring the vertical ground reaction force (vGRF) and angular impulses in the lower extremity during a single-leg landing. The study included 34 female college students, who performed the single-leg drop vertical jump. Lower extremity kinetic and kinematic data were obtained from a 3D motion analysis system. Participants were divided into valgus (N = 19) and varus (N = 15) groups according to the knee angular displacement during landings. The vGRF and angular impulses of the hip, knee, and ankle were calculated by integrating the vGRF-time curve and each joint's moment-time curve. vGRF impulses did not differ between two groups. Hip angular impulse in the valgus group was significantly smaller than that in the varus group (0.019 ± 0.033 vs. 0.067 ± 0.029 Nms/kgm, p<0.01), whereas knee angular impulse was significantly greater (0.093 ± 0.032 vs. 0.045 ± 0.040 Nms/kgm, p<0.01). There was no difference in ankle angular impulse between the groups. Our results indicate that dynamic knee valgus increases the impact the knee joint needs to attenuate during landing; conversely, the knee varus participants were able to absorb more of the landing impact with the hip joint.

Hallux Valgus Correction Comparing Percutaneous Chevron/Akin (PECA) and Open Scarf/Akin Osteotomies.

PubMed

Lee, Moses; Walsh, James; Smith, Margaret M; Ling, Jeff; Wines, Andrew; Lam, Peter

2017-08-01

Minimally invasive surgery is being used increasingly, including for hallux valgus surgery. Despite the growing interest in minimally invasive procedures, there have been few publications on percutaneous chevron/akin (PECA) procedures, and no studies have been published comparing PECA to open scarf/akin osteotomies (SA). This was a prospective, randomized study of 50 patients undergoing operative correction of hallux valgus using one of 2 techniques (PECA vs open SA). Data were collected preoperatively and on 1 day, 2 weeks, 6 weeks, and 6 months postoperatively. Outcome measures include the American Orthopaedic Foot & Ankle Society Hallux-Metatarsophalangeal-Interphalangeal (AOFAS-HMI) Score, visual analog pain score, hallux valgus angle (HVA), and 1-2 intermetatarsal angle (IMA). Twenty-five patients underwent PECA procedures and 25 patients received SA procedures. Both groups showed significantly improved AOFAS-HMI scores after surgery (PECA group: 61.8 to 88.9, SA group: 57.3 to 84.1, P = .560) with comparable final scores. HVA and IMA also presented similar outcomes at final follow-up ( P = .520 and P = .270, respectively). However, the PECA group showed significantly lower pain level (VAS) in the early postoperative phase (postoperative day 1 to postoperative week 6, P < .001 and P = .004, respectively). No serious complications were observed in either group. Both groups showed comparable good to excellent clinical and radiologic outcomes at final follow-up. However, the PECA group had significantly less pain in the first 6 weeks following surgery. Level of Evidence Level II, prospective comparative study.

Is Double Metatarsal Osteotomy Superior to Proximal Chevron Osteotomy in Treatment of Hallux Valgus With Increased Distal Metatarsal Articular Angle?

PubMed

Park, Chul Hyun; Lee, Woo-Chun

We compared the results of proximal chevron osteotomy and double metatarsal osteotomy for hallux valgus with an increased distal metatarsal articular angle (DMAA). From October 2008 to December 2012, first metatarsal osteotomies were performed in 64 patients (69 feet) with symptomatic hallux valgus associated with an increased DMAA. Proximal chevron with Akin osteotomy and lateral soft tissue release was performed in 46 feet (PCO group); double metatarsal osteotomy and Akin osteotomy without lateral soft tissue release was performed in 23 feet (DMO group). Clinical assessments were performed using the American Orthopaedic Foot and Ankle Society (AOFAS) scale and visual analog scale (VAS). The hallux valgus angles, intermetatarsal angles, sesamoid positions, metatarsus adductus angles, and DMAAs were compared at different postoperative times. Postoperative shortening of first the metatarsal and complications were compared. The mean AOFAS scale and VAS scores showed significant improvement in both groups after surgery; however, no significant difference was observed between the 2 groups. The immediate postoperative hallux valgus angle and sesamoid position were significantly larger in DMO group; however, no intergroup difference was observed at the last follow-up visit, with the hallux valgus angle gradually increasing in the PCO group. The postoperative DMAA was significantly smaller in the DMO group. The mean shortening of the first metatarsal after surgery was significantly larger in the DMO group than in the PCO group. Transfer metatarsalgia developed in 1 foot (2.2%) in the PCO group and 2 feet (8.7%) in the DMO group. Partial avascular necrosis of the metatarsal head with advanced arthritis of the first metatarsophalangeal joint developed in 1 foot (4.3%) in the DMO group. In conclusion, no differences in the clinical and radiographic results were observed between the 2 groups for hallux valgus deformity with an increased DMAA. Copyright © 2017 The American

Trampoline fracture of the proximal tibial metaphysis in children may not progress into valgus: a report of seven cases and a brief review.

PubMed

Kakel, R

2012-06-01

Fracture of the proximal tibial metaphysis in children is a rare injury but notorious for carrying the risk of subsequent valgus deformity of the tibia. Trampoline-caused fracture of the proximal tibial metaphysis in children may not progress into valgus. We followed up six children who collectively sustained seven fractures of the proximal tibial metaphysis while trampolining with other heavier and/or older children. Initial and follow-up x-rays were reviewed by an orthopaedic surgeons and two radiologists. None of the patients developed valgus deformity with follow-up. Trampoline is associated with a specific type of injury to the proximal tibia when children are trampolining with other heavier children even without falling off the trampoline. This fracture is linear and complete, often non-displaced. Unlike "other" proximal tibial metaphyseal fractures, trampoline-associated proximal tibial metaphysical fracture in children is not associated with a risk of subsequent valgus deformity. Level 4. case series. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

Extended plantar limb (modified) chevron osteotomy versus scarf osteotomy for hallux valgus correction: A randomised controlled trial.

PubMed

Mahadevan, Devendra; Lines, Stephen; Hepple, Stephen; Winson, Ian; Harries, William

2016-06-01

The purpose of this RCT was to compare the extended plantar limb (modified) chevron osteotomy with the scarf osteotomy in correcting hallux valgus deformity and improving functional scores and patient satisfaction. Patients were randomly assigned and kept blind to surgical allocation. Cases requiring additional procedures including the Akin osteotomy were excluded. Outcomes were measured at 1 year following surgery. 84 patients (109 feet) were analysed (60 modified chevron; 49 Scarf). The mean age was 50.7 years (75F: 9M). Post-operative intermetatarsal angle (IMA) was significantly lower in the modified chevron group (5.8° versus 6.9°, p=0.045). Hallux valgus angle and distal metatarsal articular angle were similar. The magnitude of IMA correction with the modified chevron was also significantly greater (9.1° versus 7.1°, p=0.007). Both osteotomies produced comparable MOxFQ scores and satisfaction ratings. The modified chevron was superior to the scarf osteotomy in correcting IMA in hallux valgus deformity. Copyright © 2015 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

Tensile Properties of the Deep Transverse Metatarsal Ligament in Hallux Valgus: A CONSORT-Compliant Article.

PubMed

Abdalbary, Sahar Ahmed; Elshaarawy, Ehab A A; Khalid, Bahaa E A

2016-02-01

The deep transverse metatarsal ligament (DTML) connects the neighboring2 metatarsal heads and is one of the stabilizers connecting the lateral sesamoid and second metatarsal head. In this study, we aimed to determine the tensile properties of the DTML in normal specimens and to compare these results with hallux valgus specimens. We hypothesized that the tensile properties of the DTML would be different between the 2 groups of specimens.The DTML in the first interspace was dissected from 12 fresh frozen human cadaveric specimens. Six cadavers had bilateral hallux valgus and the other 6 cadavers had normal feet. The initial length (L0) and cross-sectional area (A0) of the DTML were measured using a digital caliper, and tensile tests with load failure were performed using a material testing machine.There were significant between-groups differences in the initial length (L0) P = 0.009 and cross-sectional area (A0) of the DTML P = 0.007. There were also significant between-groups differences for maximum force (N) P = 0.004, maximum distance (mm) P = 0.005, maximum stress (N/mm) P = 0.003, and maximum strain (%) P = 0.006.The DTML is an anatomical structure for which the tensile properties differ in hallux valgus.

Scarf versus chevron osteotomy in hallux valgus: a randomized controlled trial in 96 patients.

PubMed

Deenik, A R; Pilot, P; Brandt, S E; van Mameren, H; Geesink, R G T; Draijer, W F

2007-05-01

The degree of correction of hallux valgus deformity using a distal chevron osteotomy is reported as limited. The scarf osteotomy is reported to correct large intermetatarsal angles (IMA). The purpose of this study was to evaluate if one technique gave greater correction of the IMA and hallux valgus angle (HVA) than the other. After informed consent, 96 feet in 83 patients were randomized into two treatment groups (49 scarf and 47 chevron osteotomies). The results were evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) Hallux Valgus Scale and radiographic HVA and IMA measurements. At 27 (range 23-31) months followup both groups improved. The AOFAS score in the chevron group improved from 48 to 89 points and in the scarf group from 47 to 91 points. In the chevron group the HVA corrected from 30 to 17 degrees, and in the scarf group the HVA corrected from 29 to 18 degrees. In both groups, the IMA was corrected from 13 to 10 degrees. The differences were not statistically significant. Three patients in the chevron group developed a partial metatarsal head necrosis. In the scarf group, four patients developed grade 1 complex regional pain syndrome compared to one patient in the chevron group. No differences of statistical significance could be measured between the two groups with respect to the AOFAS score, HVA, and IMA. Although both groups showed good to excellent results, we favor the chevron osteotomy because the procedure is technically less demanding.

Chevron versus Mitchell osteotomy in hallux valgus surgery: a comparative study.

PubMed

Lambers Heerspink, F O; Verburg, H; Reininga, I H F; van Raaij, T M

2015-01-01

Good clinical results have been reported for chevron and Mitchell osteotomies in mild hallux valgus (HV). The primary aim of the present study was to compare first metatarsal shortening after chevron and Mitchell osteotomies in HV. The secondary outcome measures were the degree of valgus correction, metatarsalgia, and patient satisfaction. A total of 84 patients were included in the present study and were treated from 2005 to 2007; 42 patients were in each group. The outcome measurements-first metatarsal length, HV angle, 1-2 intermetatarsal angle, satisfaction, and metatarsalgia-were taken preoperatively and at follow-up. The Mitchell osteotomy resulted in a significantly larger decrease in the first metatarsal length. No significant difference in transfer metatarsalgia was found. Approximately 30% of patients were mildly or not satisfied after HV surgery. Mitchell osteotomy leads to a larger decrease in the first metatarsal length. Patients with metatarsalgia performed poorly, and no significant differences in metatarsalgia were found. Preventing postoperative metatarsalgia is important for a successful outcome after HV surgery. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Radiographic assessment of knee-ankle alignment after total knee arthroplasty for varus and valgus knee osteoarthritis.

PubMed

Gao, Fuqiang; Ma, Jinhui; Sun, Wei; Guo, Wanshou; Li, Zirong; Wang, Weiguo

2017-01-01

There are unanswered questions about knee-ankle alignment after total knee arthroplasty (TKA) for varus and valgus osteoarthritis (OA) of the knee. The aim of this retrospective study was to assess knee-ankle alignment after TKA. The study consisted of 149 patients who had undergone TKA due to varus and valgus knee OA. The alignment and angles in the selected knees and ankles were measured on full-length standing anteroposterior radiographs, both pre-operatively and post-operatively. The paired t-test and Pearson's correlation tests were used for statistical analysis. The results showed that ankle alignment correlated with knee alignment both pre-operatively and postoperatively (P<0.05). The pre-operative malalignment of the knee was corrected (P<0.05), and the ankle tilt angle was accordingly improved in the operative side after TKA (P<0.05). In addition, TKA had little effect on knee-ankle alignment on the non-operative side (P>0.05). These findings indicated that routine TKA could correct the varus or valgus deformity of a knee, and improve the tilt of the ankle. Ankle alignment correlated with knee alignment both pre-operatively and postoperatively. Both pre-operative knee and ankle malalignment can be simultaneously corrected following TKA. Level III. Copyright © 2016 Elsevier B.V. All rights reserved.

Management of pain on hallux valgus with percutaneous intra-articular Pulse-Dose Radiofrequency.

PubMed

Masala, Salvatore; Fiori, Roberto; Calabria, Eros; Raguso, Mario; de Vivo, Dominique; Cuzzolino, Alessandro; Simonetti, Giovanni

2017-01-01

The purpose of our study was to investigate the role of intra-articular pulse-dose radiofrequency in management of painful hallux valgus refractory to conservative therapies. Between November 2010 and April 2012, 51 patients (15 male, 36 female) with a median age of 71.4 years were included in our clinical trial. Under fluoroscopic guidance we introduced a 22 gauge 10 cm length cannula by a percutaneous access in the first metatarsophalangeal joint and its tip was placed intra-articularly. After removing the spindle, a radiofrequency needle with a 5 mm active tip was introduced. The following parameters were used: 1200 pulses at high voltage (45 V) with 20 msec duration followed by 480 msec silent phases. A great reduction in pain intensity was documented at 1 week, 1 month and 3 months after procedures. Pain intensity increased between 5 and 8 months after treatments, so we performed a second procedure in all patients between 7 months and 9 months since the first treatment. Also in this case we obtained a great reduction of pain intensity in the first 3 months after the procedure. Pain intensity returned at preprocedural values after 9 months after second procedure. No complications were observed. Our experience shows pulse-dose radiofrequency is a safe, repeatable and effective technique for managing patients with symptomatic hallux valgus in the short and medium term. Pulse-dose radiofrequency may improve pain control and quality of life in patients with hallux valgus refractory to conservative therapies. © 2014 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

Progressive valgus angulation of the ankle secondary to loss of fibular congruity treated with medial tibial hemiepiphysiodesis and fibular reconstruction.

PubMed

Lesiak, Alex C; Esposito, Paul W

2014-06-01

The fibula is an important stabilizer of the lateral ankle. Discontinuity of the fibular shaft can lead to progressive pain and shortening of the fibula, ultimately causing loss of lateral support to the ankle. Two children, who sustained segmental bone loss of the shaft of the fibula, developed progressive symptomatic valgus of the ankle with widening of the mortice and lateral subluxation of the talus. Both patients were treated with fibular plating and grafting with tricalcium sulfate with acute reconstitution of fibular length. Distal medial tibial hemiepiphysiodesis was simultaneously performed. One patient required revision plating and grafting 14 months after the index surgery because of plate failure. The valgus angulation and the widened medial mortice were corrected in the ankles of both patients, who returned to full activities. The patients were followed to maturity; the correction has been maintained, and they remain asymptomatic. The technique used in these cases can correct valgus angulation secondary to loss of fibular congruity rather than only halting progression of the deformity.

Distal Femoral Osteotomy for the Valgus Knee: Medial Closing Wedge Versus Lateral Opening Wedge: A Systematic Review.

PubMed

Wylie, James D; Jones, Daniel L; Hartley, Melissa K; Kapron, Ashley L; Krych, Aaron J; Aoki, Stephen K; Maak, Travis G

2016-10-01

(1) To determine the radiographic correction/healing rate, patient-reported outcomes, reoperation rate, and complication rate after distal femoral osteotomy (DFO) for the valgus knee with lateral compartment pathology. (2) To summarize the reported results of medial closing wedge and lateral opening wedge DFO. We conducted a systematic review of PubMed, MEDLINE, and CINAHL to identify studies reporting outcomes of DFOs for the valgus knee. Keywords included "distal femoral osteotomy," "chondral," "cartilage," "valgus," "joint restoration," "joint preservation," "arthritis," and "gonarthrosis." Two authors first reviewed the articles; our study exclusion criteria were then applied, and the articles were included on the basis relevance defined by the aforementioned criteria. The Methodological Index for Nonrandomized Studies scale judged the quality of the literature. Sixteen studies were relevant to the research questions out of 191 studies identified by the original search. Sixteen studies were identified reporting on 372 osteotomies with mean follow-up of 45 to 180 months. All studies reported mean radiographic correction to a near neutral mechanical axis, with 3.2% nonunion and 3.8% delayed union rates. There was a 9% complication rate and a 34% reoperation rate, of which 15% were converted to arthroplasty. There were similar results reported for medial closing wedge and lateral opening wedge techniques, with a higher conversion to arthroplasty in the medial closing wedge that was confounded by longer mean follow-up in this group (mean follow-up 100 v 58 months). DFOs for the valgus knee with lateral compartment disease provide improvements in patient-reported knee health-related quality of life at midterm follow-up but have high rates of reoperation. No evidence exists proving better results of either the lateral opening wedge or medial closing wedge techniques. Level IV, systematic review of Level IV studies. Copyright © 2016 Arthroscopy Association of North

Proximal reverse chevron metatarsal osteotomy, lateral soft tissue release, and akin osteotomy through a single medial incision for hallux valgus.

PubMed

Jung, Hong-Geun; Kim, Tae-Hoon; Park, Jong-Tae; Shin, Min-Ho; Lee, Sang-Hun

2014-04-01

Scarring on the dorsal first web space after lateral soft tissue release can be a major contributor to patient dissatisfaction following hallux valgus surgery. We hypothesized that performing distal soft tissue procedure (DSTP), proximal reverse chevron metatarsal osteotomy (PCMO), and Akin osteotomy through a single medial incision would provide better clinical and radiographic results with improved patient satisfaction compared with bunion corrections performed through 2 incisions. The study included 117 feet (of 98 patients) with moderate to severe hallux valgus. Clinically, the preoperative and final follow-up visual analog scale (VAS) pain scores, the preoperative and final follow-up American Orthopaedic Foot & Ankle Society (AOFAS) hallux metatarsophalangeal (MTP)-interphalangeal (IP) scores, first MTP joint range of motion (ROM), and patient satisfaction after the surgery were evaluated. Radiographically, the hallux valgus angle (HVA), intermetatarsal angle (IMA), hallux valgus interphalangeal angle (HIA), medial sesamoid position (MSP), and first to fifth metatarsal width (1-5MTW) were analyzed before and after surgery. The mean AOFAS hallux score improved from 56.3 preoperatively to 90.6 at the final follow-up, and the mean VAS pain score decreased from 6.8 preoperatively to 1.5 at the final follow-up (P < .001). Ninety-five percent of the patients were satisfied with the surgery. Radiographically, the mean HVA decreased from 36.1 degrees (range, 16.0 to 44.0 degrees) preoperatively to 5.4 degrees (range, -12.4 to 29.7 degrees) at the final follow-up (P < .001), and the mean IMA decreased from 19.0 degrees (range, 9.0 to 28.0 degrees) preoperatively to 4.5 degrees (range, -5.0 to 14.2 degrees) at the final follow-up (P < .001). The mean 1-5MTW also decreased by 16% (16 mm) from 97.3 mm (range, 85.0 to 110.0 mm) preoperatively to 81.3 mm (range, 70.0 to 95.0 mm) at the final follow-up (P < .001). We achieved very favorable clinical and radiographic outcomes

Association of knee confidence with pain, knee instability, muscle strength, and dynamic varus-valgus joint motion in knee osteoarthritis.

PubMed

Skou, Søren T; Wrigley, Tim V; Metcalf, Ben R; Hinman, Rana S; Bennell, Kim L

2014-05-01

To investigate associations between self-reported knee confidence and pain, self-reported knee instability, muscle strength, and dynamic varus-valgus joint motion during walking. We performed a cross-sectional analysis of baseline data from 100 participants with symptomatic and radiographic medial tibiofemoral compartment osteoarthritis (OA) and varus malalignment recruited for a randomized controlled trial. The extent of knee confidence, assessed using a 5-point Likert scale item from the Knee Injury and Osteoarthritis Outcome Score, was set as the dependent variable in univariable and multivariable ordinal regression, with pain during walking, self-reported knee instability, quadriceps strength, and dynamic varus-valgus joint motion during walking as independent variables. One percent of the participants were not troubled with lack of knee confidence, 17% were mildly troubled, 50% were moderately troubled, 26% were severely troubled, and 6% were extremely troubled. Significant associations were found between worse knee confidence and higher pain intensity, worse self-reported knee instability, lower quadriceps strength, and greater dynamic varus-valgus joint motion. The multivariable model consisting of the same variables significantly accounted for 24% of the variance in knee confidence (P < 0.001). Worse knee confidence is associated with higher pain, worse self-reported knee instability, lower quadriceps muscle strength, and greater dynamic varus-valgus joint motion during walking. Since previous research has shown that worse knee confidence is predictive of functional decline in knee OA, addressing lack of knee confidence by treating these modifiable impairments could represent a new therapeutic target. Copyright © 2014 by the American College of Rheumatology.

Ninety-Degree Chevron Osteotomy for Correction of Hallux Valgus Deformity: Clinical Data and Finite Element Analysis

PubMed Central

Matzaroglou, Charalambos; Bougas, Panagiotis; Panagiotopoulos, Elias; Saridis, Alkis; Karanikolas, Menelaos; Kouzoudis, Dimitris

2010-01-01

Hallux valgus is a very common foot disorder, with its prevalence estimated at 33% in adult shoe-wearing populations. Conservative management is the initial treatment of choice for this condition, but surgery is sometimes needed. The 600 angle Chevron osteotomy is an accepted method for correction of mild to moderate hallux valgus in adults less than 60 years old. A modified 900 angle Chevron osteotomy has also been described; this modified technique can confer some advantages compared to the 600 angle method, and reported results are good. In the current work we present clinical data from a cohort of fifty-one female patients who had surgery for sixty-two hallux valgus deformities. In addition, in order to get a better physical insight and study the mechanical stresses along the two osteotomies, Finite Element Analysis (FEA) was also conducted. FEA indicated enhanced mechanical bonding with the modified 900 Chevron osteotomy, because the compressive stresses that keep the two bone parts together are stronger, and the shearing stresses that tend to slide the two bone parts apart are weaker, compared to the typical 600 technique. Follow-up data on our patient cohort show good or excellent long-term clinical results with the modified 900 angle technique. These results are consistent with the FEA-based hypothesis that a 900 Chevron osteotomy confers certain mechanical advantages compared to the typical 600 procedure. PMID:20648223

The correlation between calcaneal valgus angle and asymmetrical thoracic-lumbar rotation angles in patients with adolescent scoliosis.

PubMed

Park, Jaeyong; Lee, Sang Gil; Bae, Jongjin; Lee, Jung Chul

2015-12-01

[Purpose] This study aimed to provide a predictable evaluation method for the progression of scoliosis in adolescents based on quick and reliable measurements using the naked eye, such as the calcaneal valgus angle of the foot, which can be performed at public facilities such as schools. [Subjects and Methods] Idiopathic scoliosis patients with a Cobb's angle of 10° or more (96 females, 22 males) were included in this study. To identify relationships between factors, Pearson's product-moment correlation coefficient was computed. The degree of scoliosis was set as a dependent variable to predict thoracic and lumbar scoliosis using ankle angle and physique factors. Height, weight, and left and right calcaneal valgus angles were set as independent variables; thereafter, multiple regression analysis was performed. This study extracted variables at a significance level (α) of 0.05 by applying a stepwise method, and calculated a regression equation. [Results] Negative correlation (R=-0.266) was shown between lumbar lordosis and asymmetrical lumbar rotation angles. A correlation (R=0.281) was also demonstrated between left calcaneal valgus angles and asymmetrical thoracic rotation angles. [Conclusion] Prediction of scoliosis progress was revealed to be possible through ocular inspection of the calcaneus and Adams forward bending test and the use of a scoliometer.

Results of total knee replacement with a cruciate-retaining model for severe valgus deformity--a study of 48 patients followed for an average of 9 years.

PubMed

Koskinen, Esa; Remes, Ville; Paavolainen, Pekka; Harilainen, Arsi; Sandelin, Jerker; Tallroth, Kaj; Kettunen, Jyrki; Ylinen, Pekka

2011-06-01

The objectives of the present study were to find out the results and the factors affecting survival after primary knee arthroplasty with a cruciate-retaining prosthesis in severe valgus deformity. Forty-eight patients (52 knees) participated in the current follow-up study. All patients were followed at least 5 years or to first revision. Mean follow-up time was 9 years (range, 1 to 17 years).The Kaplan-Meier analysis revealed 79% (95% CI 68% to 91%) survival rate with revision for any reason and 81% (95% CI 70% to 93%) survival rate with revision for instability as an endpoint at 10 years. Preoperatively TFA was 23° (range, 15°-51°) in valgus and 7° (range, 21° valgus-4° varus) in valgus postoperatively. Of the 14 re-operated patients, eight were revised because of progressive postoperative medial collateral ligament instability. All re-operations were performed during the first 4 years of the follow-up. The mean TFA was 15.5° valgus postoperatively for those eight and the odds ratio for a revision was 2 (95% CI 1-3, p = 0.025) when compared to the rest of the study population. The residual valgus deformity increases the risk of re-operation and it should be avoided. If proper soft-tissue balance cannot be achieved or there is no functional medial collateral ligament present more constrained implants should be used. In selected cases where both bony correction and ligament balancing have properly been achieved the use of a cruciate-retaining type of prosthesis is justified. Copyright © 2010 Elsevier B.V. All rights reserved.

Minimally Invasive and Open Distal Chevron Osteotomy for Mild to Moderate Hallux Valgus.

PubMed

Brogan, Kit; Lindisfarne, Edward; Akehurst, Harold; Farook, Usama; Shrier, Will; Palmer, Simon

2016-11-01

Minimally invasive surgical (MIS) techniques are increasingly being used in foot and ankle surgery but it is important that they are adopted only once they have been shown to be equivalent or superior to open techniques. We believe that the main advantages of MIS are found in the early postoperative period, but in order to adopt it as a technique longer-term studies are required. The aim of this study was to compare the 2-year outcomes of a third-generation MIS distal chevron osteotomy with a comparable traditional open distal chevron osteotomy for mild-moderate hallux valgus. Our null hypothesis was that the 2 techniques would yield equivalent clinical and radiographic results at 2 years. This was a retrospective cohort study. Eighty-one consecutive feet (49 MIS and 32 open distal chevron osteotomies) were followed up for a minimum 24 months (range 24-58). All patients were clinically assessed using the Manchester-Oxford Foot Questionnaire. Radiographic measures included hallux valgus angle, the intermetatarsal angle, hallux interphalangeal angle, metatarsal phalangeal joint angle, distal metatarsal articular angle, tibial sesamoid position, shape of the first metatarsal head, and plantar offset. Statistical analysis was done using Student t test or Wilcoxon rank-sum test for continuous data and Pearson chi-square test for categorical data. Clinical and radiologic postoperative scores in all domains were substantially improved in both groups (P < .001), but there was no statistically significant difference in improvement of any domain between open and MIS groups (P > .05). There were no significant differences in complications between the 2 groups ( > .5). The midterm results of this third-generation technique show that it was a safe procedure with good clinical outcomes and comparable to traditional open techniques for symptomatic mild-moderate hallux valgus. Level III, retrospective comparative study. © The Author(s) 2016.

[Clinical effect modified Chevron osteotomy combined with lateral tissue loosening in treating mild-moderate hallux valgus through internal signal approach].

PubMed

Chen, Xue-Qiang; Wu, Qun-Feng; Dong, Wei-Qin; Yu, Li-Xin; Li, Xiong-Feng

2018-03-25

To explore clinical effect of modified Chevron osteotomy combined with lateral tissue loosening for the treatment of mild-moderate hallux valgus through internal signal approach. From July 2015 to June 2016, 26 patients with mild-moderate hallux valgus treated with modified Chevron osteotomy combined with lateral tissue loosening through internal signal approach, including 2 males and 24 females aged from 45 to 65 years old with an average of(54.6±4.8) years old;the courses of diseases ranged from 1 to 5 months with an average of (7.5±3.3) months. Hallux valgus angle(HVA), inter metatarsal angle(IMA) were measured at 12 months after operation, and AOFAS score was applied to evaluate clinical effect before and after operation. All incisions were healed at stage I. No incision occurred infection, metatarsal necrosis and recurrence of hallux valgus deformity. Two patients occurred skin numbness caused by musculocutaneous nerve injury. Twenty-six patients were followed up from 6 to 12 months with an average of(9.12±2.06) months. HVA, IMA were(30.01±3.71)°, (14.00±1.50)° before operation and(9.41±4.16)°, (7.00±0.60)° after operation, which had significant difference. There was statistical significance in AOFAS score before operation 54.77±9.59 and after operation 92.73±5.47, and 19 cases obtained excellent results and 7 moderate. Modified Chevron osteotomy combined with full thread headless pressure screw fixation and lateral tissue loosening for the treatment of mild-moderate hallux valgus has advantages of excellent exposure, simple operation, stable fixation, rapid recovery. Akin osteotomy with internal capsulorrhaphy were used with lateral loosening and could recover soft tissue balance between lateral and internal, and could receive satisfied clinical effects. Copyright© 2018 by the China Journal of Orthopaedics and Traumatology Press.

[Hindfoot valgus. Diagnosis and therapy of flatfoot].

PubMed

Radl, R; Fuhrmann, G; Maafe, M; Krifter, R-M

2012-04-01

The clinical finding of flatfoot is characterized by a flattening of the medial longitudinal arch and valgus deformity of the hindfoot. The differential diagnosis of flatfoot is the physiological, flexible, contracted flatfoot, which occurs as a congenital or acquired deformity. Congenital flatfoot deformity requires early intensive therapy, while a flexible flatfoot in children has a good prognosis and conservative treatment usually leads to a stable and sufficient load-bearing foot. Severe flatfoot in children can be corrected successfully by simple, minimally invasive procedures. In adults with symptomatic flatfoot, which usually occurs due to an insufficiency of the tendon of the tibialis posterior, conservative therapy with insoles, shoe modifications and physiotherapeutic measures can lead to significant improvement, otherwise surgical correction is recommended. Early, stage-appropriate therapy helps to prevent an impending decompensation of the hindfoot.

[Clinical effect of total knee arthroplasty on patients with knee osteoarthritis combined with mild to moderate valgus knee deformity].

PubMed

Chen, Peng; Zeng, Min; Xie, Jie; Wang, Long; Su, Weiping; Hu, Yihe

2016-09-28

To investigate the clinical effect of total knee arthroplasty on patients with knee osteoarthritis combined with mild to moderate valgus knee deformity.
 A total of 15 patients received total knee arthroplasty for correcting mild (10°-15°) to moderate (15°-30°) valgus knee between January 2011 and February 2014 in Xiangya Hospital of Central South University. We adopted a stable prosthesis surgery through patellar medial approach, osteophytes cleaning, conventional osteotomy, a selective soft tissue release and balance technical correcting of knee valgus deformity. Then conventional anticoagulation and symptomatic rehabilitation was utilized. Preoperative and postoperative X-ray was conducted in patients with measuring femor-tibial angle (FTA) and inspecting the prosthesis position. FTA, visual analog scale (VAS) standard, and parallel knee scoring system (KSS) were used to evaluate the clinical effect.
 Fifteen patients were followed up for 14 to 36 (22.40±11.88) months. The hospitalization time was 7-13 (7.73±1.58) d; operative time was 58-110 (81.8±16.85) min, the dominant blood loss was 140-600 (337.30±143.65) mL. Two cases had knee extension hysteresis, and the knee activity recovered after exercise. Leg power lines were normal. Three postoperative cases suffered anterior knee pain. They were subjected to celecoxib analgesic treatment and the pain gradually eased after 3 months. One postoperative case showed incision discharge and swelling, which was healed after change of dressing. During follow-up, review of X-ray film does not show prosthesis loose, subsidence and other complications. The knee valgus angle (8.1±1.8)°, knee motion range (107.33±9.61)°, KSS knee score (74.7±14.5, 75.3±2.7) and pain score (2.5±0.9) were significantly better than the preoperative (P<0.05). The clinical and function KSS scores showed that the improvement rate was 80%. 
 Total knee arthroplasty is an effective way to treat patients with knee osteoarthritis

Ninety-degree chevron osteotomy for correction of hallux valgus deformity: clinical data and finite element analysis.

PubMed

Matzaroglou, Charalambos; Bougas, Panagiotis; Panagiotopoulos, Elias; Saridis, Alkis; Karanikolas, Menelaos; Kouzoudis, Dimitris

2010-04-22

Hallux valgus is a very common foot disorder, with its prevalence estimated at 33% in adult shoe-wearing populations. Conservative management is the initial treatment of choice for this condition, but surgery is sometimes needed. The 60(0) angle Chevron osteotomy is an accepted method for correction of mild to moderate hallux valgus in adults less than 60 years old. A modified 90(0) angle Chevron osteotomy has also been described; this modified technique can confer some advantages compared to the 60(0) angle method, and reported results are good. In the current work we present clinical data from a cohort of fifty-one female patients who had surgery for sixty-two hallux valgus deformities. In addition, in order to get a better physical insight and study the mechanical stresses along the two osteotomies, Finite Element Analysis (FEA) was also conducted. FEA indicated enhanced mechanical bonding with the modified 90(0) Chevron osteotomy, because the compressive stresses that keep the two bone parts together are stronger, and the shearing stresses that tend to slide the two bone parts apart are weaker, compared to the typical 60(0) technique. Follow-up data on our patient cohort show good or excellent long-term clinical results with the modified 90(0) angle technique. These results are consistent with the FEA-based hypothesis that a 90(0) Chevron osteotomy confers certain mechanical advantages compared to the typical 60(0) procedure.

Rehabilitation after hallux valgus surgery: importance of physical therapy to restore weight bearing of the first ray during the stance phase.

PubMed

Schuh, Reinhard; Hofstaetter, Stefan G; Adams, Samuel B; Pichler, Florian; Kristen, Karl-Heinz; Trnka, Hans-Joerg

2009-09-01

Operative treatment of people with hallux valgus can yield favorable clinical and radiographic results. However, plantar pressure analysis has demonstrated that physiologic gait patterns are not restored after hallux valgus surgery. The purpose of this study was to illustrate the changes of plantar pressure distribution during the stance phase of gait in patients who underwent hallux valgus surgery and received a multimodal rehabilitation program. This was a prospective descriptive study. Thirty patients who underwent Austin (n=20) and scarf (n=10) osteotomy for correction of mild to moderate hallux valgus deformity were included in this study. Four weeks postoperatively they received a multimodal rehabilitation program once per week for 4 to 6 weeks. Plantar pressure analysis was performed preoperatively and 4 weeks, 8 weeks, and 6 months postoperatively. In addition, range of motion of the first metatarsophalangeal joint was measured, and the American Orthopaedic Foot and Ankle Society (AOFAS) forefoot questionnaire was administered preoperatively and at 6 months after surgery. The mean AOFAS score significantly increased from 60.7 points (SD=11.9) preoperatively to 94.5 points (SD=4.5) 6 months after surgery. First metatarsophalangeal joint range of motion increased at 6 months postoperatively, with a significant increase in isolated dorsiflexion. In the first metatarsal head region, maximum force increased from 117.8 N to 126.4 N and the force-time integral increased from 37.9 N.s to 55.6 N.s between the preoperative and 6-month assessments. In the great toe region, maximum force increased from 66.1 N to 87.2 N and the force-time integral increased from 18.7 N.s to 24.2 N.s between the preoperative and 6-month assessments. A limitation of the study was the absence of a control group due to the descriptive nature of the study. The results suggest that postoperative physical therapy and gait training may lead to improved function and weight bearing of the first

Risk factors of avascular necrosis of the femoral head and fixation failure in patients with valgus angulated femoral neck fractures over the age of 50 years.

PubMed

Song, Hyung Keun; Choi, Ho June; Yang, Kyu Hyun

2016-12-01

The aim of our study was to identify the risk factors for avascular necrosis of the femoral head (AVN) and fixation failure (FF) after screw osteosynthesis in patients with valgus angulated femoral neck fractures. We conducted a retrospective study of 308 patients (mean age, 72.5 years, range, 50-97 years), with a mean follow-up of 21.4 months (range, 12-64 months). The risk for failure in treatment (FIT) associated with patient- and fracture-related factors was evaluated by logistic regression analyses. FIT was identified in 32 cases (10.3%): 22 cases (7.1%) of AVN and 10 cases (3.2%) of FF. Initial valgus tilt>15° (p=0.023), posterior tilt>15° (p=0.012), and screw sliding distance (p=0.037) were significantly associated with FIT. FIT occurred in 7 patients (5.2%) with B1.2.1 fractures and 17 patients (48.6%) with B1.1.2 fractures (p<0.001). The odds of FIT were 17-fold higher in patients with initial valgus and posterior tilts>15° (B1.1.2) compared to patients with <15° of tilt in both planes (B1.2.1). The severity of initial deformity predicts AVN and FF in patients with valgus angulated femoral neck fractures. Patients with an initial valgus and posterior tilt>15° are reasonable candidates for primary arthroplasty due to high risk of FIT. Copyright © 2016 Elsevier Ltd. All rights reserved.

Treatment of moderate hallux valgus by percutaneous, extra-articular reverse-L Chevron (PERC) osteotomy.

PubMed

Lucas y Hernandez, J; Golanó, P; Roshan-Zamir, S; Darcel, V; Chauveaux, D; Laffenêtre, O

2016-03-01

The aim of this study was to report a single surgeon series of consecutive patients with moderate hallux valgus managed with a percutaneous extra-articular reverse-L chevron (PERC) osteotomy. A total of 38 patients underwent 45 procedures. There were 35 women and three men. The mean age of the patients was 48 years (17 to 69). An additional percutaneous Akin osteotomy was performed in 37 feet and percutaneous lateral capsular release was performed in 22 feet. Clinical and radiological assessments included the type of forefoot, range of movement, the American Orthopedic Foot and Ankle (AOFAS) score, a subjective rating and radiological parameters. The mean follow-up was 59.1 months (45.9 to 75.2). No patients were lost to follow-up. The mean AOFAS score increased from 62.5 (30 to 80) pre-operatively to 97.1 (75 to 100) post-operatively. A total of 37 patients (97%) were satisfied. At the last follow up there was a statistically significant decrease in the hallux valgus angle, the intermetatarsal angle and the proximal articular set angle. The range of movement of the first metatarsophalangeal joint improved significantly.. There was more improvement in the range of movement in patients who had fixation of the osteotomy of the proximal phalanx. Preliminary results of this percutaneous approach are promising. This technique is reliable and reproducible. Its main asset is that it maintains an excellent range of movement. The PERC osteotomy procedure is an effective approach for surgical management of moderate hallux valgus which combines the benefits of percutaneous surgery with the versatility of the chevron osteotomy whilst maintaining excellent first MTPJ range of motion. ©2016 The British Editorial Society of Bone & Joint Surgery.

The influence of personality traits on the subjective outcome of operative hallux valgus correction.

PubMed

Radl, Roman; Leithner, Andreas; Zacherl, Maximilian; Lackner, Ursula; Egger, Josef; Windhager, Reinhard

2004-10-01

We studied prospectively the influence of personality traits on the subjective outcome of a chevron osteotomy in 42 patients with hallux valgus. The mean age of patients was 48.3 (20-70) years. Personality traits were evaluated by the means of the Freiburg Personality Inventory (FPI-R). Three months postoperatively 37 patients were satisfied, and five patients not satisfied with the operative procedure. The preoperative AOFAS Score improved from an average of 48.7 (30-65) points to 87.9 (50-100) points. A comparison of satisfied and dissatisfied patients revealed statistically significant differences in the personality traits aggressiveness (p=0.003), extraversion (p=0.001) and health worries (p=0.04). The postoperative hallux valgus angle was 12.2+/-7.8 degrees and 13.4+/-8.3 degrees (p=0.74) among satisfied and not satisfied patients, respectively, and the intermetatarsal angle (I-II) was 7.4+/-2.5 degrees and 7.6+/-4 degrees (p=0.89), respectively. The results suggest that the patient's subjective result after the operative correction may be influenced by some individual, personality profiles.

Proximal metatarsal osteotomy for hallux valgus: an audit of radiologic outcome after single screw fixation and full postoperative weightbearing

PubMed Central

2013-01-01

Background Proximal metatarsal osteotomy combined with a distal soft-tissue procedure is a common treatment for moderate to severe hallux valgus. Secure stabilisation of the metatarsal osteotomy is necessary to avoid complications such as delayed union, nonunion or malunion as well as loss of correction. The aim of this study was to report our results using a single screw for stabilisation of the osteotomy. Methods We retrospectively reviewed 151 patients with severe hallux valgus who were treated by the above mentioned way with full postoperative weightbearing in a stiff soled shoe. Mean age of patients at time of surgery was 54 years, 19 patients were male and 132 female. Assessment of clinical and radiographic results was performed after 2 days and 6 weeks. Results were also correlated to the experience of the performing surgeon. Results Mean preoperative HVA (hallux valgus angle) was 36.4 degrees, and then 3.5 degrees 2 days and 13.4 degrees 6 weeks after the procedure (p < 0.001). Mean preoperative IMA (intermetarsal angle) was 16.8 degrees, and then 6.4 degrees after 2 days and 9.8 degrees after 6 weeks (p < 0.001). Mean preoperative first metatarsal length of 56.4 mm decreased to 53.6 mm after 6 weeks. Possible non-union of the osteotomy was observed in 4 patients (2.6%) after 6 weeks. Performing residents (n = 40) operated in 65 minutes and attending surgeons (n = 111) in 45 minutes, with no significant differences in radiographic measurements between both groups. Conclusions Single screw stabilisation of proximal chevron osteotomy is a reliable method for treating severe hallux valgus deformities with satisfactory results. PMID:23725485

Injury tolerance and moment response of the knee joint to combined valgus bending and shear loading.

PubMed

Bose, Dipan; Bhalla, Kavi S; Untaroiu, Costin D; Ivarsson, B Johan; Crandall, Jeff R; Hurwitz, Shepard

2008-06-01

Valgus bending and shearing of the knee have been identified as primary mechanisms of injuries in a lateral loading environment applicable to pedestrian-car collisions. Previous studies have reported on the structural response of the knee joint to pure valgus bending and lateral shearing, as well as the estimated injury thresholds for the knee bending angle and shear displacement based on experimental tests. However, epidemiological studies indicate that most knee injuries are due to the combined effects of bending and shear loading. Therefore, characterization of knee stiffness for combined loading and the associated injury tolerances is necessary for developing vehicle countermeasures to mitigate pedestrian injuries. Isolated knee joint specimens (n=40) from postmortem human subjects were tested in valgus bending at a loading rate representative of a pedestrian-car impact. The effect of lateral shear force combined with the bending moment on the stiffness response and the injury tolerances of the knee was concurrently evaluated. In addition to the knee moment-angle response, the bending angle and shear displacement corresponding to the first instance of primary ligament failure were determined in each test. The failure displacements were subsequently used to estimate an injury threshold function based on a simplified analytical model of the knee. The validity of the determined injury threshold function was subsequently verified using a finite element model. Post-test necropsy of the knees indicated medial collateral ligament injury consistent with the clinical injuries observed in pedestrian victims. The moment-angle response in valgus bending was determined at quasistatic and dynamic loading rates and compared to previously published test data. The peak bending moment values scaled to an average adult male showed no significant change with variation in the superimposed shear load. An injury threshold function for the knee in terms of bending angle and shear

The percutaneous pie-crusting medial release during arthroscopic procedures of the medial meniscus does neither affect valgus laxity nor clinical outcome.

PubMed

Jeon, Sang-Woo; Jung, Min; Chun, Yong-Min; Lee, Su-Keon; Jung, Woo Seok; Choi, Chong Hyuk; Kim, Sung-Jae; Kim, Sung-Hwan

2017-12-28

To analyze the effect of percutaneous pie-crusting medial release on valgus laxity before and after surgery and on clinical outcomes. Eight-hundred fourteen consecutive patients who underwent an arthroscopic procedure for the medial compartment of the knee were evaluated retrospectively. Sex, age, type of operation (meniscectomy, meniscal repair, and posterior root repair), type of accompanying surgery (none, cartilage procedure, ligament procedure and osteotomy) were documented. Sixty-four patients who underwent percutaneous pie-crusting medial release (release group) and 64 who did not undergo medial release (non-release group) were matched using the propensity score method. Each patient was evaluated for the following variables: degree of valgus laxity on stress radiographs, Lysholm knee score, visual analog scale score, and International Knee Documentation Committee knee score and grade. At the 24-month follow-up, no significant increase in side-to-side differences in the valgus gap was observed in comparison to the preoperative value in the release group [preoperative, - 0.1 ± 1.3 mm; follow-up, - 0.1 ± 1.4 mm; (n.s.)]. The follow-up Lysholm score, visual analog scale score and International Knee Documentation Committee knee score and grade were similar between the two groups. Percutaneous pie-crusting medial release is an additional procedure that can be performed during arthroscopic surgery for patients with a narrow medial joint space of the knee. Percutaneous pie-crusting medial release reduces iatrogenic injury to the cartilage and does not produce any residual valgus laxity of the knee. IV.

Comparison of outcomes between proximal and distal chevron osteotomy, both with supplementary lateral soft-tissue release, for severe hallux valgus deformity: A prospective randomised controlled trial.

PubMed

Park, H-W; Lee, K-B; Chung, J-Y; Kim, M-S

2013-04-01

Severe hallux valgus deformity is conventionally treated with proximal metatarsal osteotomy. Distal metatarsal osteotomy with an associated soft-tissue procedure can also be used in moderate to severe deformity. We compared the clinical and radiological outcomes of proximal and distal chevron osteotomy in severe hallux valgus deformity with a soft-tissue release in both. A total of 110 consecutive female patients (110 feet) were included in a prospective randomised controlled study. A total of 56 patients underwent a proximal procedure and 54 a distal operation. The mean follow-up was 39 months (24 to 54) in the proximal group and 38 months (24 to 52) in the distal group. At follow-up the hallux valgus angle, intermetatarsal angle, distal metatarsal articular angle, tibial sesamoid position, American Orthopaedic Foot and Ankle Society (AOFAS) hallux metatarsophalangeal-interphalangeal score, patient satisfaction level, and complications were similar in each group. Both methods showed significant post-operative improvement and high levels of patient satisfaction. Our results suggest that the distal chevron osteotomy with an associated distal soft-tissue procedure provides a satisfactory method for correcting severe hallux valgus deformity.

Effect of medial arch support foot orthosis on plantar pressure distribution in females with mild-to-moderate hallux valgus after one month of follow-up.

PubMed

Farzadi, Maede; Safaeepour, Zahra; Mousavi, Mohammad E; Saeedi, Hassan

2015-04-01

Higher plantar pressures at the medial forefoot are reported in hallux valgus. Foot orthoses with medial arch support are considered as an intervention in this pathology. However, little is known about the effect of foot orthoses on plantar pressure distribution in hallux valgus. To investigate the effect of a foot orthosis with medial arch support on pressure distribution in females with mild-to-moderate hallux valgus. Quasi-experimental. Sixteen female volunteers with mild-to-moderate hallux valgus participated in this study and used a medial arch support foot orthosis for 4 weeks. Plantar pressure for each participant was assessed using the Pedar-X(®) in-shoe system in four conditions including shoe-only and foot orthosis before and after the intervention. The use of the foot orthosis for 1 month led to a decrease in peak pressure and maximum force under the hallux, first metatarsal, and metatarsals 3-5 (p < 0.05). In the medial midfoot region, peak pressure, maximum force, and contact area were significantly higher with the foot orthosis than shoe-only before and after the intervention (p = 0.00). A foot orthosis with medial arch support could reduce pressure beneath the hallux and the first metatarsal head by transferring the load to the other regions. It would appear that this type of foot orthosis can be an effective method of intervention in this pathology. Findings of this study will improve the clinical knowledge about the effect of the medial arch support foot orthosis used on plantar pressure distribution in hallux valgus pathology. © The International Society for Prosthetics and Orthotics 2014.

[Surgical technique and clinical results of total knee arthroplasty in treating endstage gonarthrosis combined with valgus knee deformity].

PubMed

Wang, Xingshan; Weng, Xisheng; Lin, Jin; Jin, Jin; Qian, Wenwei

2012-05-01

To investigate the surgical technique and the clinical results of total knee arthroplasty (TKA) in treating end-stage gonarthrosis combined with valgus knee deformity. Between November 1998 and October 2010, 64 patients (72 knees) with end-stage gonarthrosis combined with valgus knee deformity underwent TKA by a medial parapatellar approach. Of the 64 patients, 18 were male and 46 were female with an average age of 62.5 years (range, 23-82 years), including 44 cases (49 knees) of osteoarthritis, 17 cases (20 knees) of rheumatoid arthritis, 2 cases (2 knees) of haemophilic arthritis, and 1 case (1 knee) of post-traumatic arthritis. Bilateral knees were involved in 8 cases, and single knee in 56 cases. The flexion and extension range of motion (ROM) of the knee joint was (82.2 +/- 28.7) degrees; the femur-tibia angle (FTA) was (18.0 +/- 5.8) degrees; according to Knee Society Score (KSS) criterion, the preoperative clinical score was 31.2 +/- 10.1 and functional score was 37.3 +/- 9.0. According to Krackow's classification, there were 65 knees of type I and 7 knees of type II. By medial parapatellar approach, conventional osteotomy and Ranawat soft tissue release were performed in all cases. Prosthesis of preserved posterior cruciate ligament were used in 7 cases (7 knees), posterior stabilize prosthesis in 54 cases (60 knees), constrained prosthesis in 4 cases (5 knees). Incisions healed by first intention in all cases. Peroneal nerve palsy occurred in 1 patient with haemophilic arthritis, severe valgus deformity (FTA was 41 degrees), and flexion contracture (20 degrees), which was cured after 1 year of conservative treatment. Revison surgery was performed in 1 case of deep infection at 2 years after surgery. All the patients were followed up 4.9 years on average (range, 1-13 years). At last follow-up, the FTA was (7.0 +/- 2.5) degrees, showing significant difference when compared with preoperative value (t = 15.502, P = 0.000). The KSS clinical score was 83.0 +/- 6

Distal chevron osteotomy with lateral soft tissue release for moderate to severe hallux valgus decided using intraoperative varus stress radiographs.

PubMed

Kim, Hyong-Nyun; Park, Yoo-Jung; Kim, Gab-Lae; Park, Yong-Wook

2013-01-01

The purpose of the present study was to investigate the outcomes of distal chevron osteotomy with lateral soft tissue release for moderate to severe hallux valgus. The patients were selected using criteria that included the degree of lateral soft tissue contracture and metatarsocuneiform joint flexibility. The contracture and flexibility were determined from intraoperative varus stress radiographs. From April 2007 to May 2009, 56 feet in 51 consecutive patients with moderate to severe hallux valgus had undergone distal chevron osteotomy with lateral soft tissue release. This was done when the lateral soft tissue contracture was not so severe that passive correction of the hallux valgus deformity was not possible and when the metatarsocuneiform joint was flexible enough to permit additional correction of the first intermetatarsal angle after lateral soft tissue release. The mean patient age was 45.2 (range 23 to 54) years, and the duration of follow-up was 27.5 (range 24 to 46) months. The mean hallux abductus angle decreased from 33.5° ± 3.1° to 11.6° ± 3.3°, and the first intermetatarsal angle decreased from 16.4° ± 2.7° to 9.7° ± 2.1°. The mean American Orthopaedic Foot and Ankle Society hallux-interphalangeal scores increased from 66.6° ± 10.7° to 92.6° ± 9.4° points, and 46 of the 51 patients (90%) were either very satisfied or satisfied with the outcome. No recurrence of deformity or osteonecrosis of the metatarsal head occurred. When lateral soft tissue contracture is not severe and when the metatarsocuneiform joint is flexible enough, distal chevron osteotomy with lateral soft tissue release can be a useful and effective choice for moderate to severe hallux valgus deformity. Copyright © 2013 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Varus and valgus stress tests after total knee arthroplasty with and without anesthesia.

PubMed

Tsukeoka, Tadashi; Tsuneizumi, Yoshikazu

2016-03-01

Retrospective studies demonstrated inadequate soft tissue balance is associated with the long-term outcome of total knee arthroplasty (TKA). However, most of these studies have evaluated the joint laxity only postoperatively without anesthesia. Therefore information about the effect of anesthesia on knee laxity is important for soft tissue balancing at the time of surgery. This study was conducted to determine how anesthesia affects the varus and valgus stress tests after TKA. A consecutive series of 26 patients undergoing staged bilateral TKA was evaluated. Varus and valgus laxity of the knee with the TKA implant was measured a few days before the contralateral TKA without anesthesia and again immediately after the contralateral TKA under spinal anesthesia. The laxity was significantly increased from 3.0° to 3.6° (p = 0.005) and from 4.7° to 5.7° (p = 0.007) in medial and lateral side, respectively, when the stress tests were performed under anesthesia in comparison to the laxity measured without anesthesia. The major change in laxity (≥3°) was measured in 6 (23%) patients tested without anesthesia. Anesthesia significantly influenced knee joint laxity after TKA. The findings of this study suggest that muscular forces impart a stabilizing force across the joint.

Comparison of distal chevron osteotomy with and without lateral soft tissue release for the treatment of hallux valgus.

PubMed

Lee, Ho-Jin; Chung, Jin-Wha; Chu, In-Tak; Kim, Yoon-Chung

2010-04-01

A lateral soft tissue release is often performed with distal chevron osteotomy for the correction of hallux valgus deformities. However, many complications of lateral soft tissue release have been reported. To define the necessity of lateral soft tissue release, the authors compared the clinical and radiographic results of distal chevron osteotomy with and without it. 86 consecutive patients (152 feet) were enrolled in this prospective study. In Group A, 45 patients (74 feet) underwent a chevron osteotomy with lateral soft tissue release. In Group B, 41 patients (78 feet) underwent a chevron osteotomy without it. Mean followup was 1.7 years and 2.1 years, respectively. The hallux valgus angle (HVA) and intermetatarsal angle (IMA), and AOFAS score were measured preoperatively, and 1-year followup postoperatively and complications were evaluated. The change in HVA, IMA and AOFAS score were insignificant (p > 0.05) between Group A and Group B, however, the range of motion of the first metatarsophalangeal joint was significantly less in Group A (p < 0.05). Complications of digital neuritis and cosmetically dissatisfied scarring of the dorsal web space were seen only in Group A. No cases had avascular necrosis of the metatarsal head, malunion or nonunion. Lateral soft tissue release may not be needed for mild or moderate hallux valgus deformities which may prevent decreased range of motion of the first metatarsophalangeal joint, neuritis of dorsal or plantar lateral digital nerve and cosmetic dissatisfaction of a dorsal scar.

Conservative management of pes valgus with plantar flexed talus, flexible.

PubMed

Bleck, E E; Berzins, U J

1977-01-01

The type of flat foot that we have called pes valgus with plantar flexed talus, flexible, was treated in children with the Helfet heel seat or the UCBL shoe insert. In follow-up examination of 71 cases for periods longer than one year, 79 per cent of the patients showed that the UCBL shoe insert and the Helfet heel seat improved the clinical and roentgenographic appearance of the foot. The Helfet heel seat is recommended in cases where the plantar flexion angle of the talus is 35 to 45 degrees and the UCBL shoe insert in those cases of plantar flexion of the talus greater than 45 degrees.

A comparison of men's and women's strength to body mass ratio and varus/valgus knee angle during jump landings.

PubMed

Haines, Tracie L; McBride, Jeffrey M; Triplett, N Travis; Skinner, Jared W; Fairbrother, Kimberly R; Kirby, Tyler J

2011-10-01

The purpose of this investigation was to compare valgus/varus knee angles during various jumps and lower body strength between males and females relative to body mass. Seventeen recreationally active females (age: 21.94 ± 2.59 years; height: 1.67 ± 0.05 m; mass: 64.42 ± 8.39 kg; percent body fat: 26.89 ± 6.26%; squat one-repetition maximum: 66.18 ± 19.47 kg; squat to body mass ratio: 1.03 ± 0.28) and 13 recreationally active males (age: 21.69 ± 1.65 years; height: 1.77 ± 0.07 m; mass: 72.39 ± 9.23 kg; percent body fat: 13.15 ± 5.18%; squat one-repetition maximum: 115.77 ± 30.40 kg; squat to body mass ratio: 1.59 ± 0.31) performed a one-repetition maximum in the squat and three of each of the following jumps: countermovement jump, 30 cm drop jump, 45 cm drop jump, and 60 cm drop jump. Knee angles were analysed using videography and body composition was analysed by dual-energy X-ray absorptiometry to allow for squat to body mass ratio and squat to fat free mass ratio to be calculated. Significant differences (P ≤ 0.05) were found between male and female one-repetition maximum, male and female squat to body mass ratio, and male and female squat to fat free mass ratio. Significant differences were found between male and female varus/valgus knee positions during maximum flexion of the right and left leg in the countermovement jump, drop jump from 30 cm, drop jump from 45 cm, and drop jump from 60 cm. Correlations between varus/valgus knee angles and squat to body mass ratio for all jumps displayed moderate, non-significant relationships (countermovement jump: r = 0.445; drop jump from 30 cm: r = 0.448; drop jump from 45 cm: r = 0.449; drop jump from 60 cm: r = 0.439). In conclusion, males and females have significantly different lower body strength and varus/valgus knee position when landing from jumps.

Postoperative pain and preemptive local anesthetic infiltration in hallux valgus surgery.

PubMed

Gądek, Artur; Liszka, Henryk; Wordliczek, Jerzy

2015-03-01

Several techniques of anesthesia are used in foot surgery. Preemptive analgesia helps to prevent the development of hypersensitivity in the perioperative period. The aim of our study was to assess the role of preemptive local anesthetic infiltration and postoperative pain after hallux valgus surgery. We evaluated 118 patients who underwent modified chevron and mini-invasive Mitchell-Kramer bunionectomy of the first distal metatarsal. After spinal anesthesia each patient randomly received an infiltration of local anesthetic or the same amount of normal saline 10 minutes before the skin incision. We measured the intensity of pain 4, 8, 12, 16, 24, and 72 hours after the release of the tourniquet using a visual analogue scale (VAS). Rescue analgesia and all other side effects were noted. Preemptive analgesia resulted in less pain during the first 24 hours after surgery. The decrease of VAS score was significantly lower in the study group during all the short postoperative periods measured. The rescue analgesia was administered in 11.9% of patients in the injected group and 42.4% in the placebo group (P < .05). In the injected group we did not observe significant difference in VAS score between patients post-chevron and miniinvasive Mitchell-Kramer osteotomy of the first distal metatarsal. No systemic adverse effects were noted. One persistent injury of dorsomedial cutaneous nerve was observed. Preemptive local anesthetic infiltration was an efficient and safe method to reduce postoperative pain after hallux valgus surgery. The analgesic effect was satisfactory in both traditional and minimally invasive techniques. © The Author(s) 2014.

Proximal Intermetatarsal Divergence in Distal Chevron Osteotomy for Hallux Valgus: An Overlooked Finding.

PubMed

Akpinar, Evren; Buyuk, Abdul Fettah; Cetinkaya, Engin; Gursu, Sarper; Ucpunar, Hanifi; Albayrak, Akif

2016-01-01

The goal of distal chevron osteotomy for hallux valgus is to restore proper first-toe joint alignment by performing lateral translation of the distal first metatarsal fragment (the metatarsal head). We hypothesized that in some patients this procedure might also result in involuntary medial translation of the proximal first metatarsal fragment, which we called proximal intermetatarsal divergence. The aim of the present study was to compare the pre- and postoperative radiographs of patients with hallux valgus to determine whether we could identify proximal intermetatarsal divergence. We retrospectively compared the pre- and postoperative radiographs of 29 feet in 28 patients treated with distal chevron osteotomy. Two different methods were used to measure the intermetatarsal angles: the anatomic intermetatarsal angle (aIMA) and the mechanical intermetatarsal angle (mIMA). The maximum intermetatarsal distance (MID) was also measured. We defined proximal intermetatarsal divergence as a postoperative increase in the aIMA or MID, coupled with a decrease in the mIMA. For data analysis, we divided the patients into low-angle (mild deformity) and high-angle (severe deformity) groups, according to their preoperative mIMA. The mean ± standard deviation patient age was 41 ± 14 years. In the low-angle group, the mean mIMA decreased (from 10.91° to 7.00°), the mean aIMA increased (from 11.80° to 13.55°), and the mean MID increased (from 17.97 mm to 20.60 mm; p = .001, for all). In the high-angle group, the mean mIMA decreased (from 14.30° to 6.90°; p = .001), the mean aIMA decreased (from 14.77° to 13.54°; p = .06), and the mean MID decreased (from 20.74 mm to 20.37 mm; p = .64). The results of our study suggest that proximal intermetatarsal divergence might occur after distal chevron osteotomy for hallux valgus, primarily in patients with a low preoperative mIMA. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All

Inter and intra-observer reliability in assessment of the position of the lateral sesamoid in determining the severity of hallux valgus.

PubMed

Panchani, Sunil; Reading, Jonathan; Mehta, Jaysheel

2016-06-01

The position of the lateral sesamoid on standard dorso-plantar weight bearing radiographs, with respect to the lateral cortex of the first metatarsal, has been shown to correlate well with the degree of the hallux valgus angle. This study aimed to assess the inter- and intra-observer error of this new classification system. Five orthopaedic consultants and five trainee orthopaedic surgeons were recruited to assess and document the degree of displacement of the lateral sesamoid on 144 weight-bearing dorso-plantar radiographs on two separate occasions. The severity of hallux valgus was defined as normal (0%), mild (≤50%), moderate (51-≤99%) or severe (≥100%) depending on the percentage displacement of the lateral sesamoid body from the lateral cortical border of the first metatarsal. Consultant intra-observer variability showed good agreement between repeated assessment of the radiographs (mean Kappa=0.75). Intra-observer variability for trainee orthopaedic surgeons also showed good agreement with a mean Kappa=0.73. Intraclass correlations for consultants and trainee surgeons was also high. The new classification system of assessing the severity of hallux valgus shows high inter- and intra-observer variability with good agreement and reproducibility between surgeons of consultant and trainee grades. Copyright © 2015 Elsevier Ltd. All rights reserved.

KENO-VI Primer: A Primer for Criticality Calculations with SCALE/KENO-VI Using GeeWiz

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowman, Stephen M

2008-09-01

The SCALE (Standardized Computer Analyses for Licensing Evaluation) computer software system developed at Oak Ridge National Laboratory is widely used and accepted around the world for criticality safety analyses. The well-known KENO-VI three-dimensional Monte Carlo criticality computer code is one of the primary criticality safety analysis tools in SCALE. The KENO-VI primer is designed to help a new user understand and use the SCALE/KENO-VI Monte Carlo code for nuclear criticality safety analyses. It assumes that the user has a college education in a technical field. There is no assumption of familiarity with Monte Carlo codes in general or with SCALE/KENO-VImore » in particular. The primer is designed to teach by example, with each example illustrating two or three features of SCALE/KENO-VI that are useful in criticality analyses. The primer is based on SCALE 6, which includes the Graphically Enhanced Editing Wizard (GeeWiz) Windows user interface. Each example uses GeeWiz to provide the framework for preparing input data and viewing output results. Starting with a Quickstart section, the primer gives an overview of the basic requirements for SCALE/KENO-VI input and allows the user to quickly run a simple criticality problem with SCALE/KENO-VI. The sections that follow Quickstart include a list of basic objectives at the beginning that identifies the goal of the section and the individual SCALE/KENO-VI features that are covered in detail in the sample problems in that section. Upon completion of the primer, a new user should be comfortable using GeeWiz to set up criticality problems in SCALE/KENO-VI. The primer provides a starting point for the criticality safety analyst who uses SCALE/KENO-VI. Complete descriptions are provided in the SCALE/KENO-VI manual. Although the primer is self-contained, it is intended as a companion volume to the SCALE/KENO-VI documentation. (The SCALE manual is provided on the SCALE installation DVD.) The primer provides specific

Postoperative alignment of TKA in patients with severe preoperative varus or valgus deformity: is there a difference between surgical techniques?

PubMed

Rahm, Stefan; Camenzind, Roland S; Hingsammer, Andreas; Lenz, Christopher; Bauer, David E; Farshad, Mazda; Fucentese, Sandro F

2017-06-21

There have been conflicting studies published regarding the ability of various total knee arthroplasty (TKA) techniques to correct preoperative deformity. The purpose of this study was to compare the postoperative radiographic alignment in patients with severe preoperative coronal deformity (≥10° varus/valgus) who underwent three different TKA techniques; manual instrumentation (MAN), computer navigated instrumentation (NAV) and patient specific instrumentation (PSI). Patients, who received a TKA with a preoperative coronal deformity of ≥10° with available radiographs were included in this retrospective study. The groups were: MAN; n = 54, NAV; n = 52 and PSI; n = 53. The mechanical axis (varus / valgus) and the posterior tibial slope were measured and analysed using standing long leg- and lateral radiographs. The overall mean postoperative varus / valgus deformity was 2.8° (range, 0 to 9.9; SD 2.3) and 2.5° (range, 0 to 14.7; SD 2.3), respectively. The overall outliers (>3°) represented 30.2% (48 /159) of cases and were distributed as followed: MAN group: 31.5%, NAV group: 34.6%, PSI group: 24.4%. No significant statistical differences were found between these groups. The distribution of the severe outliers (>5°) was 14.8% in the MAN group, 23% in the NAV group and 5.6% in the PSI group. The PSI group had significantly (p = 0.0108) fewer severe outliers compared to the NAV group while all other pairs were not statistically significant. In severe varus / valgus deformity the three surgical techniques demonstrated similar postoperative radiographic alignment. However, in reducing severe outliers (> 5°) and in achieving the planned posterior tibial slope the PSI technique for TKA may be superior to computer navigation and the conventional technique. Further prospective studies are needed to determine which technique is the best regarding reducing outliers in patients with severe preoperative coronal deformity.

Factors affecting femoral rotational angle based on the posterior condylar axis in gap-based navigation-assisted total knee arthroplasty for valgus knee.

PubMed

Lee, Sung-Sahn; Lee, Yong-In; Kim, Dong-Uk; Lee, Dae-Hee; Moon, Young-Wan

2018-01-01

Achieving proper rotational alignment of the femoral component in total knee arthroplasty (TKA) for valgus knee is challenging because of lateral condylar hypoplasia and lateral cartilage erosion. Gap-based navigation-assisted TKA enables surgeons to determine the angle of femoral component rotation (FCR) based on the posterior condylar axis. This study evaluated the possible factors that affect the rotational alignment of the femoral component based on the posterior condylar axis. Between 2008 and 2016, 28 knees were enrolled. The dependent variable for this study was FCR based on the posterior condylar axis, which was obtained from the navigation system archives. Multiple regression analysis was conducted to identify factors that might predict FCR, including body mass index (BMI), Kellgren-Lawrence grade (K-L grade), lateral distal femoral angles obtained from the navigation system and radiographs (NaviLDFA, XrayLDFA), hip-knee-ankle (HKA) axis, lateral gap under varus stress (LGVS), medial gap under valgus stress (MGVS), and side-to-side difference (STSD, MGVS - LGVS). The mean FCR was 6.1° ± 2.0°. Of all the potentially predictive factors evaluated in this study, only NaviLDFA (β = -0.668) and XrayLDFA (β = -0.714) predicted significantly FCR. The LDFAs, as determined using radiographs and the navigation system, were both predictive of the rotational alignment of the femoral component based on the posterior condylar axis in gap-based TKA for valgus knee. A 1° increment with NaviLDFA led to a 0.668° decrement in FCR, and a 1° increment with XrayLDFA led to a 0.714° decrement. This suggests that symmetrical lateral condylar hypoplasia of the posterior and distal side occurs in lateral compartment end-stage osteoarthritis with valgus deformity.

Karl Ludloff (1864-1945): An Inventive Orthopedic Surgeon, His Work and His Surgical Technique for the Correction of Hallux Valgus.

PubMed

Markatos, Konstantinos; Karaoglanis, Georgios; Damaskos, Christos; Garmpis, Nikolaos; Tsourouflis, Gerasimos; Laios, Konstantinos; Tsoucalas, Gregory

2018-05-01

The purpose of this article is to summarize the work and pioneering achievements in the field of orthopedic surgery of the German orthopedic surgeon Karl Ludloff. Ludloff had an impact in the diagnostics, physical examination, orthopedic imaging, and orthopedic surgical technique of his era. He was a pioneer in the surgical treatment of dysplastic hip, anterior cruciate ligament reconstruction, and hallux valgus. His surgical technique for the correction of hallux valgus, initially stabilized with plaster of Paris, remained unpopular among other orthopedic surgeons for decades. In the 1990s, the advent and use of improved orthopedic materials for fixation attracted the interest of numerous orthopedic surgeons in the Ludloff osteotomy for its ability to correct the deformity in all 3 dimensions, its anatomic outcomes, and its low recurrence rate and patient satisfaction.

A comparison of proximal and distal Chevron osteotomy, both with lateral soft-tissue release, for moderate to severe hallux valgus in patients undergoing simultaneous bilateral correction: a prospective randomised controlled trial.

PubMed

Lee, K B; Cho, N Y; Park, H W; Seon, J K; Lee, S H

2015-02-01

Moderate to severe hallux valgus is conventionally treated by proximal metatarsal osteotomy. Several recent studies have shown that the indications for distal metatarsal osteotomy with a distal soft-tissue procedure could be extended to include moderate to severe hallux valgus. The purpose of this prospective randomised controlled trial was to compare the outcome of proximal and distal Chevron osteotomy in patients undergoing simultaneous bilateral correction of moderate to severe hallux valgus. The original study cohort consisted of 50 female patients (100 feet). Of these, four (8 feet) were excluded for lack of adequate follow-up, leaving 46 female patients (92 feet) in the study. The mean age of the patients was 53.8 years (30.1 to 62.1) and the mean duration of follow-up 40.2 months (24.1 to 80.5). After randomisation, patients underwent a proximal Chevron osteotomy on one foot and a distal Chevron osteotomy on the other. At follow-up, the American Orthopedic Foot and Ankle Society (AOFAS) hallux metatarsophalangeal interphalangeal (MTP-IP) score, patient satisfaction, post-operative complications, hallux valgus angle, first-second intermetatarsal angle, and tibial sesamoid position were similar in each group. Both procedures gave similar good clinical and radiological outcomes. This study suggests that distal Chevron osteotomy with a distal soft-tissue procedure is as effective and reliable a means of correcting moderate to severe hallux valgus as proximal Chevron osteotomy with a distal soft-tissue procedure. ©2015 The British Editorial Society of Bone & Joint Surgery.

Clinical relevance of valgus deformity of proximal femur in cerebral palsy.

PubMed

Lee, Kyoung Min; Kang, Jong Yeol; Chung, Chin Youb; Kwon, Dae Gyu; Lee, Sang Hyeong; Choi, In Ho; Cho, Tae-Joon; Yoo, Won Joon; Park, Moon Seok

2010-01-01

Proximal femoral deformity related to physis has not been studied in patients with cerebral palsy (CP). This study was performed to investigate the clinical relevance of neck shaft angle (NSA), head shaft angle (HSA), and proximal femoral epiphyseal shape in patients with CP, which represent the deformities of metaphysis, physis, and epiphysis, respectively. Three hundred eighty-four patients with CP (mean age 9.1 y, 249 males and 135 females) were included. Extent of involvement and functional states [Gross Motor Function Classification System (GMFCS) level] were obtained. Radiographic measurements including NSA, HSA, and qualitative shape of the proximal femoral epiphysis were evaluated and analyzed according to extent of involvement and GMFCS level. Reliability and correlation with each measurement were assessed. Multiple regression test was performed to examine the significant contributing factors to migration percentage (MP) that represents hip instability. NSA showed excellent interobserver reliability with intraclass correlation coefficients of 0.976. Correlation with the MP was higher in the NSA (r=0.419, P<0.001) than in the HSA (r=0.256, P<0.001). NSA, HSA, and MP tended to increase with increasing GMFCS level, and proportion of valgus deformed proximal femoral epiphysis also increased with increasing GMFCS level, which means valgus deformity and unstable hips in the less favorable functional states. Multiple regression analysis revealed NSA, GMFCS level, and shape of the proximal femoral epiphysis to be significant factors affecting MP. NSA appeared to be more clinically relevant than HSA in evaluating proximal femoral deformity in patients with CP. Shape of proximal femoral epiphysis is believed to have clinical implications in terms of hip instability. Diagnostic level II.

Increased knee valgus alignment and moment during single-leg landing after overhead stroke as a potential risk factor of anterior cruciate ligament injury in badminton.

PubMed

Kimura, Yuka; Ishibashi, Yasuyuki; Tsuda, Eiichi; Yamamoto, Yuji; Hayashi, Yoshimitsu; Sato, Shuichi

2012-03-01

In badminton, knees opposite to the racket-hand side received anterior cruciate ligament (ACL) injuries during single-leg landing after overhead stroke. Most of them occurred in the backhand-side of the rear court. Comparing lower limb biomechanics during single-leg landing after overhead stroke between the forehand-side and backhand-side court may help explain the different injury rates depending on court position. The knee kinematics and kinetics during single-leg landing after overhead stroke following back-stepping were different between the forehand-side and backhand-side court. Controlled laboratory study. Hip, knee and ankle joint kinematic and knee kinetic data were collected for 17 right-handed female college badminton players using a 3-dimensional motion analysis system. Subjects performed single-left-legged landing after an overhead stroke following left and right back-stepping. The kinematic and kinetic data of the left lower extremities during landing were measured and compared between left and right back-steps. Hip flexion and abduction and knee valgus at the initial contact, hip and knee flexion and knee valgus at the maximum knee flexion and the maximum knee valgus moment were significantly larger for the left back-step than the right back-step (p<0.05). Significant differences in joint kinematics and kinetics of the lower extremity during single-leg landing after overhead stroke were observed between different back-step directions. Increased knee valgus angle and moment following back-stepping to the backhand-side might be related to the higher incidence of ACL injury during single-leg landing after overhead stroke.

A Prospective Study of Distal Metatarsal Chevron Osteotomies with K-Wire Fixations to Treat Hallux Valgus Deformities.

PubMed

Baig, M N; Baig, Usman; Tariq, Ali; Din, Robert

2017-09-20

Introduction Hallux valgus is one of the most common forefoot deformities worldwide. Females are affected more often than males. The three most common clinical symptoms are the painful bunion, transfer metatarsalgia, and hammer or claw toes. Methods This case series consisted of 20 patients who had chevron osteotomy from January 2015 to January 2016. The clinical assessment was measured by The American Orthopedic Foot and Ankle Score (AOFAS), and radiologic assessment was determined by preoperative and postoperative hallux valgus angle (HVA) and intermetatarsal angle (IMA). Results The patients' mean age was 56 years. Out of 20 patients, 19 were female, and one was male. The mean AOFAS improved from 51 preoperatively to 82 postoperatively. The HVA improved from 26° preoperatively to 14°. There were five complications including four Kirschner (K)-wire complications. Conclusion Distal chevron osteotomy is a reliable and time-tested procedure. The K-wire fixation has a relatively high complication rate. We planned to use other methods of fixation and then compared them with K-wires fixation results for future studies.

A Prospective Study of Distal Metatarsal Chevron Osteotomies with K-Wire Fixations to Treat Hallux Valgus Deformities

PubMed Central

Baig, Usman; Tariq, Ali; Din, Robert

2017-01-01

Introduction Hallux valgus is one of the most common forefoot deformities worldwide. Females are affected more often than males. The three most common clinical symptoms are the painful bunion, transfer metatarsalgia, and hammer or claw toes. Methods This case series consisted of 20 patients who had chevron osteotomy from January 2015 to January 2016. The clinical assessment was measured by The American Orthopedic Foot and Ankle Score (AOFAS), and radiologic assessment was determined by preoperative and postoperative hallux valgus angle (HVA) and intermetatarsal angle (IMA). Results The patients’ mean age was 56 years. Out of 20 patients, 19 were female, and one was male. The mean AOFAS improved from 51 preoperatively to 82 postoperatively. The HVA improved from 26° preoperatively to 14°. There were five complications including four Kirschner (K)-wire complications. Conclusion Distal chevron osteotomy is a reliable and time-tested procedure. The K-wire fixation has a relatively high complication rate. We planned to use other methods of fixation and then compared them with K-wires fixation results for future studies. PMID:29167752

The results of Scarf osteotomy combined with distal soft tissue procedure are mostly satisfactory in surgical management of moderate to severe hallux valgus.

PubMed

Şaylı, Uğur; Akman, Budak; Tanrıöver, Altuğ; Kaspar, Çiğdem; Güven, Melih; Özler, Turhan

2017-05-29

Intrinsically stable diaphyseal osteotomy gained popularity in recent years for symptomatic hallux valgus deformities. In this study, Scarf osteotomy results, in surgical management of moderate to severe hallux valgus, are presented. Study group consisted of 40 feet of 32 (28 females, four males) patients surgically managed by Scarf osteotomy between September 2009 and 2011, with a mean age of 52,98 (range, 31-75) years at the time of surgery. Patient satisfaction and VAS were used for subjective evaluation while for objective measures AOFAS score, first metatarsophalangeal joint ROM and radiological measurements (intermetatarsal, hallux valgus and distal metatarsal articular angles) were evaluated. Mean follow-up period was 38 (range, 24-60) months. Sixteen feet (40%) were reported as very satisfied, 19 (47,5%) as satisfied and the remaining five (12,5%) as unsatisfied resulting with a total of 35 (87,5%) satisfaction. The mean preoperative VAS and AOFAS forefoot scores improved from 8,13±0,791 to 2,68±1,228 (p=0,0001) and from 58,25±6,15 to 78,25±8,13 (p=0,0001) on the final follow-up, respectively. The postoperative change of first metatarsophalangeal joint ROM was not statistically significant (p=0,281). On the radiological evaluation; intermetatarsal and hallux valgus angles improved from a mean value of 14,77±1,76 to 8,13±1,52° (p=0,0001) and from 35,28±5,86 to 20,10±5,55° (p=0,0001), respectively. Distal metatarsal articular angle did not show any statistically significant change (p=0,195). Scarf osteotomy combined with distal soft tissue procedure is a technically demanding procedure. The osteotomy is intrinsically stable and the correction power is high and the results are mostly satisfactory. Copyright © 2017. Published by Elsevier Ltd.

29 CFR 1926.1126 - Chromium (VI).

Code of Federal Regulations, 2014 CFR

2014-07-01

... activity involving chromium cannot release dusts, fumes, or mists of chromium (VI) in concentrations at or... 29 Labor 8 2014-07-01 2014-07-01 false Chromium (VI). 1926.1126 Section 1926.1126 Labor... Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI) in all forms...

29 CFR 1926.1126 - Chromium (VI).

Code of Federal Regulations, 2012 CFR

2012-07-01

... activity involving chromium cannot release dusts, fumes, or mists of chromium (VI) in concentrations at or... 29 Labor 8 2012-07-01 2012-07-01 false Chromium (VI). 1926.1126 Section 1926.1126 Labor... Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI) in all forms...

29 CFR 1926.1126 - Chromium (VI).

Code of Federal Regulations, 2011 CFR

2011-07-01

... activity involving chromium cannot release dusts, fumes, or mists of chromium (VI) in concentrations at or... 29 Labor 8 2011-07-01 2011-07-01 false Chromium (VI). 1926.1126 Section 1926.1126 Labor... Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI) in all forms...

29 CFR 1926.1126 - Chromium (VI).

Code of Federal Regulations, 2013 CFR

2013-07-01

... activity involving chromium cannot release dusts, fumes, or mists of chromium (VI) in concentrations at or... 29 Labor 8 2013-07-01 2013-07-01 false Chromium (VI). 1926.1126 Section 1926.1126 Labor... Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI) in all forms...

[Clinical and radiographic evaluation of a new percutaneous technique for moderate to severe hallux valgus deformity].

PubMed

Vélez-de Lachica, J C; Valdez-Jiménez, L A; Inzunza-Sánchez, J M

2017-01-01

Hallux valgus is considered the most common musculoskeletal deformity, with a prevalence of 88%. There are more than 130 surgical techniques for its treatment; currently, percutaneous ones are popular; however, they do not take into account the metatarsal-phalangeal correction angle. The aim of this study is to propose a modified technique for the correction of the percutaneous metatarsal-phalangeal and inter-metatarsal angles and to evaluate its clinical and radiological results. An experimental, prospective and longitudinal study in 10 patients with moderate to severe hallux valgus according to the classification of Coughlin and Mann were collected; the results were evaluated with the AOFAS scale at 15, 30, 60 and 90 days. The McBride technique and the technique of percutaneous anchor with the proposed amendment were performed. The AOFAS scale was applied as described, finding a progressive increase of the rating; the average correction of the inter-metatarsal angle was 8.8 degrees and of the metatarsal-phalangeal, 9.12. The modified technique of percutaneous anchor showed clear clinical and radiographic improvements in the short term. Our modified technique is proposed for future projects, including a large sample with long-term follow-up.

[Dynamic plantar pressure distribution after percutaneous hallux valgus correction using the Reverdin-Isham osteotomy].

PubMed

Rodríguez-Reyes, Gerardo; López-Gavito, Eduardo; Pérez-Sanpablo, Alberto Isaac; Galván Duque-Gastélum, Carlos; Alvarez-Camacho, Michelín; Mendoza-Cruz, Felipe; Parra-Téllez, Patricia; Vázquez-Escamilla, Jesús; Quiñones-Urióstegui, Ivett

2014-07-01

Percutaneous surgical techniques are suitable for the correction of the hallux valgus deformity. Satisfactory aesthetic and functional results obtained with the Reverdin- Isham osteotomy have been reported. The aim of this study was to describe dynamic plantar pressure redistribution after the correction of the deformity using this technique. A sample of 20 feet with mild or moderate hallux valgus was conformed and surgically treated using the Reverdin-Isham osteotomy. Clinical, radiological, surface and pressure assessments were performed pre and postoperatively. Postoperative mean (± SD) values of the American Orthopaedic Foot and Ankle Society (AOFAS) score, metatarsophalangeal, first intermetatarsal and proximal articular sect angles were 95.7 (3.3), 15.5° (5.4), 9.5° (1.5) y 5.3° (3.0), respectively. A significant decrease was observed in surface values of both lateral (P = 0.003) and medial (P = 0.001) masks of the forefoot. Mean pressure values of the lateral forefoot region denoted a significant increase (P < 0.001) while the medial forefoot region showed no change (P = 0.137). There is evidence that this particular surgical technique promotes a new plantar pressure pattern in the foot that might significantly favour the increase of the pressure observed under the lesser metatarsal heads and might not induce meaningful changes in the mean pressure registered under the first metatarsal head and hallux.

Early proximal tibial valgus osteotomy as a very important prognostic factor in Thai children with infantile tibia vara.

PubMed

Kaewpornsawan, Kamolporn; Tangsataporn, Suksan; Jatunarapit, Ratiporn

2005-10-01

To find the effectiveness of the early surgery (2-3 years of age)as a very important prognostic factor affecting the outcomes in Thai children with infantile tibia vara and all the prognostic factors including the usefulness of arthrographic study in correcting the deformity. From 1994 to 2004, sixteen children aged average 3.61 years old (2.08-7.0) were treated in Siriraj Hospital and diagnosed as infantile tibia vara by Langenskiold radiographic staging were included in the present study and retrospectively reviewed with an average of 6.4 years follow up (range 6 month - 11.1 years). All cases were initially treated by surgery because of low compliance for brace or brace failure. They consisted of 3 boys and 13 girls. There were 24 legs including the bilateral involvement in 8 cases (2 boy and 6 girls). After arihrography, the midshaft fibular osteotomy was performed then the proximal tibial dome-shaped valgus osteotomy was done and fixed with 2 pins. The desired position was 12 degree knee valgus . The patients were divided in two groups, 1)group A,the successful group with the knee becoming normal without any deformity after single osteotomy, 2)group B,the recurrent group with recurrence of the varus deformity required further corrective osteotomies to make normal axis of the knee. All variables were analyzed and compared between group A and group B. The general characteristics and radiographic findings were recorded in 1)age, 2)sex, 3)side, 4)weight in kilogram and in percentage of normal or overweight(obesity) compared with the standard Thai weight chart, 5)tibiofemoral angle (TFA) pre and postoperative treatment, 6) metaphyseal diaphyseal angle (MDA), 7)the medial physeal slope angle (MPS, 8)The preoperative arthrographic articulo-diaphyseal angle (ADA), 9.arthrographic articulo-medial physeal angle (AMPA). There were 14 legs in group A and the remaining 10 legs were in group B (average 2.4 operations). All cases healed in good alignment of the legs without

Diverse anaerobic Cr(VI) tolerant bacteria from Cr(VI)-contaminated 100H site at Hanford

NASA Astrophysics Data System (ADS)

Chakraborty, R.; Phan, R.; Lam, S.; Leung, C.; Brodie, E. L.; Hazen, T. C.

2007-12-01

Hexavalent Chromium [Cr(VI)] is a widespread contaminant found in soil, sediment, and ground water. Cr(VI) is more soluble, toxic, carcinogenic, and mutagenic compared to its reduced form Cr(III). In order to stimulate microbially mediated reduction of Cr(VI), a poly-lactate compound HRC was injected into the chromium contaminated aquifers at site 100H at Hanford. Based on the results of the bacterial community composition using high-density DNA microarray analysis of 16S rRNA gene products, we recently investigated the diversity of the dominant anaerobic culturable microbial population present at this site and their role in Cr(VI) reduction. Positive enrichments set up at 30°C using specific defined anaerobic media resulted in the isolation of an iron reducing isolate strain HAF, a sulfate reducing isolate strain HBLS and a nitrate reducing isolate, strain HLN among several others. Preliminary 16S rDNA sequence analysis identifies strain HAF as Geobacter metallireducens, strain HLN as Pseudomonas stutzeri and strain HBLS as a member of Desulfovibrio species. Strain HAF isolated with acetate as the electron donor utilized propionate, glycerol and pyruvate as alternative carbon sources, and reduced metals like Mn(IV) and Cr(VI). Growth was optimal at 37°C, pH of 6.5 and 0% salinity. Strain HLN isolated with lactate as electron donor utilized acetate, glycerol and pyruvate as alternative carbon sources, and reduced metals like Mn(IV) and Cr(VI). Optimal growth was observed at 37°C, at a pH of 7.5 and 0.3% salinity. Anaerobic active washed cell suspension of strain HLN reduced almost 95 micromolar Cr(VI) within 4 hours relative to controls. Further, with 100 micromolar Cr(VI) as the sole electron acceptor, cells of strain HLN grew to cell numbers of 4.05X 107/ml over a period of 24hrs after an initial lag, demonstrating direct enzymatic Cr(VI) reduction by this species. 10mM lactate served as the sole electron donor. These results demonstrate that Cr(VI

Correction of moderate to severe hallux valgus with combined proximal opening wedge and distal chevron osteotomies: a reliable technique.

PubMed

Jeyaseelan, L; Chandrashekar, S; Mulligan, A; Bosman, H A; Watson, A J S

2016-09-01

The mainstay of surgical correction of hallux valgus is first metatarsal osteotomy, either proximally or distally. We present a technique of combining a distal chevron osteotomy with a proximal opening wedge osteotomy, for the correction of moderate to severe hallux valgus. We reviewed 45 patients (49 feet) who had undergone double osteotomy. Outcome was assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) and the Short Form (SF) -36 Health Survey scores. Radiological measurements were undertaken to assess the correction. The mean age of the patients was 60.8 years (44.2 to 75.3). The mean follow-up was 35.4 months (24 to 51). The mean AOFAS score improved from 54.7 to 92.3 (p < 0.001) and the mean SF-36 score from 59 to 86 (p < 0.001). The mean hallux valgus and intermetatarsal angles were improved from 41.6(o) to 12.8(o) (p < 0.001) and from 22.1(o) to 7.1(o), respectively (p < 0.001). The mean distal metatarsal articular angle improved from 23(o) to 9.7(o). The mean sesamoid position, as described by Hardy and Clapham, improved from 6.8 to 3.5. The mean length of the first metatarsal was unchanged. The overall rate of complications was 4.1% (two patients). These results suggest that a double osteotomy of the first metatarsal is a reliable, safe technique which, when compared with other metatarsal osteotomies, provides strong angular correction and excellent outcomes with a low rate of complications. Cite this article: Bone Joint J 2016;98-B:1202-7. ©2016 The British Editorial Society of Bone & Joint Surgery.

Ferrate(VI) oxidation of zinc-cyanide complex.

PubMed

Yngard, Ria; Damrongsiri, Seelawut; Osathaphan, Khemarath; Sharma, Virender K

2007-10-01

Zinc-cyanide complexes are found in gold mining effluents and in metal finishing rinse water. The effect of Zn(II) on the oxidation of cyanide by ferrate(VI) (Fe(VI)O(4)(2-), Fe(VI)) was thus investigated by studying the kinetics of the reaction of Fe(VI) with cyanide present in a potassium salt of a zinc cyanide complex (K(2)Zn(CN)(4)) and in a mixture of Zn(II) and cyanide solutions as a function of pH (9.0-11.0). The rate-law for the oxidation of Zn(CN)(4)(2-) by Fe(VI) was found to be -d[Fe(VI)]/dt=k[Fe(VI)][Zn(CN)(4)(2-)](0.5). The rate constant, k, decreased with an increase in pH. The effect of temperature (15-45 degrees C) on the oxidation was studied at pH 9.0, which gave an activation energy of 45.7+/-1.5kJmol(-1). The cyanide oxidation rate decreased in the presence of the Zn(II) ions. However, Zn(II) ions had no effect on the cyanide removal efficiency by Fe(VI) and the stoichiometry of Fe(VI) to cyanide was approximately 1:1; similar to the stoichiometry in absence of Zn(II) ions. The destruction of cyanide by Fe(VI) resulted in cyanate. The experiments on removal of cyanide from rinse water using Fe(VI) demonstrated complete conversion of cyanide to cyanate.

A comparison of proximal and distal chevron osteotomy for the correction of moderate hallux valgus deformity.

PubMed

Park, C-H; Jang, J-H; Lee, S-H; Lee, W-C

2013-05-01

The purpose of this study was to compare the results of proximal and distal chevron osteotomy in patients with moderate hallux valgus. We retrospectively reviewed 34 proximal chevron osteotomies without lateral release (PCO group) and 33 distal chevron osteotomies (DCO group) performed sequentially by a single surgeon. There were no differences between the groups with regard to age, length of follow-up, demographic or radiological parameters. The clinical results were assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) scoring system and the radiological results were compared between the groups. At a mean follow-up of 14.6 months (14 to 32) there were no significant differences in the mean AOFAS scores between the DCO and PCO groups (93.9 (82 to 100) and 91.8 (77 to 100), respectively; p = 0.176). The mean hallux valgus angle, intermetatarsal angle and sesamoid position were the same in both groups. The metatarsal declination angle decreased significantly in the PCO group (p = 0.005) and the mean shortening of the first metatarsal was significantly greater in the DCO group (p < 0.001). We conclude that the clinical and radiological outcome after a DCO is comparable with that after a PCO; longer follow-up would be needed to assess the risk of avascular necrosis.

76 FR 60593 - Title VI; Proposed Circular

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-29

... DEPARTMENT OF TRANSPORTATION Federal Transit Administration [Docket No. FTA-2011-0054] Title VI... complying with Title VI of the Civil Rights Act of 1964. The purpose of this Circular is to provide.... Department of Transportation's Title VI regulations (49 CFR part 21). FTA is updating its Title VI Circular...

Hindfoot Valgus following Interlocking Nail Treatment for Tibial Diaphysis Fractures: Can the Fibula Be Neglected?

PubMed Central

Uzun, Metin; Kara, Adnan; Adaş, Müjdat; Karslioğlu, Bülent; Bülbül, Murat; Beksaç, Burak

2014-01-01

Purpose. We evaluated whether intramedullary nail fixation for tibial diaphysis fractures with concomitant fibula fractures (except at the distal one-third level) managed conservatively with an associated fibula fracture resulted in ankle deformity and assessed the impact of the ankle deformity on lower extremity function. Methods. Sixty middle one-third tibial shaft fractures with associated fibular fractures, except the distal one-third level, were included in this study. All tibial shaft fractures were anatomically reduced and fixed with interlocking intramedullary nails. Fibular fractures were managed conservatively. Hindfoot alignment was assessed clinically. Tibia and fibular lengths were compared to contralateral measurements using radiographs. Functional results were evaluated using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Foot and Ankle Disability Index Score (FADI). Results. Anatomic union, defined as equal length in operative and contralateral tibias, was achieved in 60 fractures (100%). Fibular shortening was identified in 42 fractures (68%). Mean fibular shortening was 1.2 cm (range, 0.5–2 cm). Clinical exams showed increased hindfoot valgus in 42 fractures (68%). The mean KOOS was 88.4, and the mean FADI score was 90. Conclusion. Fibular fractures in the middle or proximal one-third may need to be stabilized at the time of tibial intramedullary nail fixation to prevent development of hindfoot valgus due to fibular shortening. PMID:25544899

Reduction of ferrate(VI) and oxidation of cyanate in a Fe(VI)-TiO2-UV-NCO- system.

PubMed

Winkelmann, Kurt; Sharma, Virender K; Lin, Yekaterina; Shreve, Katherine A; Winkelmann, Catherine; Hoisington, Laura J; Yngard, Ria A

2008-08-01

The aqueous photocatalytic degradation of cyanate (NCO(-)), which is a long-lived neurotoxin formed during the remediation of cyanide in industrial waste streams, was studied in the ferrate(VI)-UV-TiO2-NCO(-) system. Kinetics measurements of the photocatalytic reduction of ferrate(VI) were carried out as a function of [NCO(-)], [ferrate(VI)], [O(2)], light intensity (I(o)), and amount of TiO2 in suspensions at pH 9.0. The photocatalytic reduction rate of ferrate(VI) in the studied system can be expressed as -d[Fe(VI)]/dt=kI(o)(0.5) [NCO(-)] [TiO2]. The rate of photocatalytic oxidation of cyanate with ferrate(VI) was greater than the rate in the analogous system without ferrate(VI). The possibility of involvement of reactive ferrate(V) species for this enhancement was determined by studying the reactivity of ferrate(V) with NCO(-) in a homogeneous solution using a premix pulse radiolysis technique. The rate constant for the reaction of ferrate(V) and NCO(-) in alkaline medium was estimated to be (9.60+/-0.07) x 10(2) M(-1) s(-1), which is much slower than the ferrate(VI) self-decomposition reaction (k approximately 10(7) M(-1) s(-1)). An analysis of the kinetic data in the Fe(VI)-UV-TiO2-NCO(-) system suggests that ferrate(V) is not directly participating in the oxidation of cyanate. Possible reactions in the system are presented to explain results of ferrate(VI) reduction and oxidation of cyanate.

29 CFR 1915.1026 - Chromium (VI).

Code of Federal Regulations, 2012 CFR

2012-07-01

... a specific process, operation, or activity involving chromium cannot release dusts, fumes, or mists... 29 Labor 7 2012-07-01 2012-07-01 false Chromium (VI). 1915.1026 Section 1915.1026 Labor... § 1915.1026 Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI...

29 CFR 1915.1026 - Chromium (VI).

Code of Federal Regulations, 2011 CFR

2011-07-01

... a specific process, operation, or activity involving chromium cannot release dusts, fumes, or mists... 29 Labor 7 2011-07-01 2011-07-01 false Chromium (VI). 1915.1026 Section 1915.1026 Labor... § 1915.1026 Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI...

29 CFR 1915.1026 - Chromium (VI).

Code of Federal Regulations, 2013 CFR

2013-07-01

... a specific process, operation, or activity involving chromium cannot release dusts, fumes, or mists... 29 Labor 7 2013-07-01 2013-07-01 false Chromium (VI). 1915.1026 Section 1915.1026 Labor... § 1915.1026 Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI...

29 CFR 1915.1026 - Chromium (VI).

Code of Federal Regulations, 2014 CFR

2014-07-01

... a specific process, operation, or activity involving chromium cannot release dusts, fumes, or mists... 29 Labor 7 2014-07-01 2014-07-01 false Chromium (VI). 1915.1026 Section 1915.1026 Labor... § 1915.1026 Chromium (VI). (a) Scope. (1) This standard applies to occupational exposures to chromium (VI...

Varus-valgus stability at 90° flexion correlates with the stability at midflexion range more widely than that at 0° extension in posterior-stabilized total knee arthroplasty.

PubMed

Hino, Kazunori; Kutsuna, Tatsuhiko; Watamori, Kunihiko; Kiyomatsu, Hiroshi; Ishimaru, Yasumitsu; Takeba, Jun; Watanabe, Seiji; Shiraishi, Yoshitaka; Miura, Hiromasa

2017-10-01

Midflexion stability can potentially improve the outcome of total knee arthroplasty (TKA). The purpose of this study was to evaluate the correlation between varus-valgus stability at 0° of extension and 90° of flexion and that at the midflexion range in posterior-stabilized (PS)-TKA. Forty-three knees that underwent PS-TKA were evaluated. Manual mild passive varus-valgus stress was applied to the knees, and the postoperative maximum varus-valgus stability was measured every 10° throughout range of motion, using a navigation system. Correlations between the stability at 0°, 90° of flexion, and that at each midflexion angle were evaluated using Spearman's correlation coefficients. The stability of 0° modestly correlated with that of 10°-20°, but it did not significantly correlate with that of 30°-80°. However, the stability of 90° strongly correlated with that of 60°-80°, modestly correlated with that of 40°-50°, weakly correlated with that of 20°-30°, and did not correlate with that of 10°. The present study confirmed the importance of acquiring stability at 90° flexion to achieve midflexion stability in PS-TKA. However, initial flexion stability did not strongly correlate with the stability at either 0° or 90°. Our findings can provide useful information for understanding varus-valgus stability throughout the range of motion in PS-TKA. Attention to soft tissue balancing is necessary to stabilize a knee at the initial flexion range in PS-TKA.

29 CFR 1926.1126 - Chromium (VI).

Code of Federal Regulations, 2010 CFR

2010-07-01

... is present or is likely to be present from skin or eye contact with chromium (VI), the employer shall... cleaned in a manner that minimizes skin or eye contact with chromium (VI) and effectively prevents the... CFR 1926.51 Where skin contact with chromium (VI) occurs, the employer shall provide washing...

Impact of podiatry resident experience level in hallux valgus surgery on postoperative outcomes.

PubMed

Fleischer, Adam E; Yorath, Martin C; Joseph, Robert M; Baron, Adam; Nordquist, Thomas; Moore, Braden J; Robinson, Richmond C O; Reilly, Charles H

2014-06-15

Despite modern advancements in transosseous fixation and operative technique, hallux valgus (i.e., bunion) surgery is still associated with a higher than usual amount of patient dissatisfaction and is generally recognized as a complex and nuanced procedure requiring precise osseous and capsulotendon balancing. It stands to reason then that familiarity and skill level of trainee surgeons might impact surgical outcomes in this surgery. The aim of this study was to determine whether podiatry resident experience level influences midterm outcomes in hallux valgus surgery (HVS). Consecutive adults who underwent isolated HVS via distal metatarsal osteotomy at a single US metropolitan teaching hospital from January 2004 to January 2009 were contacted and asked to complete a validated outcome measure of foot health (Manchester-Oxford Foot Questionnaire) regarding their operated foot. Resident experience level was quantified using the surgical logs for the primary resident of record at the time of each case. Associations were assessed using linear and logistic regression analyses. A total of 102 adult patients (n = 102 feet) agreed to participate with a mean age of 46.8 years (standard deviation 13.1, range 18-71) and average length of follow-up 6.2 y (standard deviation 1.4, range 3.6-8.6). Level of trainee experience was not associated with postoperative outcomes in either the univariate (odds ratio 0.99 [95% confidence interval, 0.98-1.01], P = 0.827) or multivariate analyses (odds ratio 1.00 [95% confidence interval, 0.97-1.02], P = 0.907). We conclude that podiatry resident level of experience in HVS does not contribute appreciably to postoperative clinical outcomes. Copyright © 2014 Elsevier Inc. All rights reserved.

Effects of Corrective Taping on Balance and Gait in Patients With Hallux Valgus.

PubMed

Gur, Gozde; Ozkal, Ozden; Dilek, Burcu; Aksoy, Songul; Bek, Nilgun; Yakut, Yavuz

2017-05-01

Taping is an effective temporary therapy for improving hallux valgus (HV) in adults. Although HV has been demonstrated to impair postural balance, there is a lack of information about how corrective taping affects balance and gait patterns in adults with HV deformity. Eighteen middle-aged female patients (average age, 53.5 years) with HV were included. Corrective tape was applied to correct HV angulation. A series of balance and gait stability tests were performed before applying tape and 1 hour after the tape was applied with a Balance Master computerized posturography device. The study involved the following tests: modified clinical test of sensory interaction and balance (mCTSIB), unilateral stance (US), limit of stability (LoS), step up/over (SUO), and walk across (WA) tests. No significant difference was found between the no-tape and taped condition in the static balance mCTSIB and US tests ( P > .05). The taping intervention resulted in significant improvement in the dynamic balance measures for the LoS test's backward reaction time and left maximum excursion ( P < .05), a significantly higher impact index bilaterally in the SUO assessment ( P < .05), and an increase in step width mean and variability in the WA test ( P < .05). Taping for correcting HV angulation had negative acute effects on dynamic balance in the SUO and WA tests and positive effects in the LoS test. Corrective taping, although a form of conservative treatment for hallux valgus, has been insufficiently studied in terms of effects on balance. Our results show that taping, as an acute effect, may impair balance in middle-aged adults when walking or ascending and descending stairs.

Influence of varus/valgus positioning of the Nanos® and Metha® short-stemmed prostheses on stress shielding of metaphyseal bone.

PubMed

Brinkmann, V; Radetzki, F; Gutteck, N; Delank, S; Zeh, A

2017-03-01

The aim of this study was to analyze bone remodeling around the Nanos® (Smith & Nephew) and Metha® (Aesculap AG) implants as a function of varus/valgus stem positioning. In 75 patients with diagnosed coxarthrosis, either Nanos® (n= 51) or Metha® (n= 24) prostheses were implanted. Digital assessment of plain radiographs immediately, 97 days, and 381 days after THA showed no clinically-relevant migration, angulation, or change in offset and center of rotation. The DEXA scans showed significant BMD changes in Gruen zones 1 (-12.8%), 2 (-3.3%), 6 (+6.4%), and 7(-7.8%)(t-test). The pre/postoperative CCD for the Nanos® was 129°/ 135° and for the Metha® 131°/ 127°. Linear regression analysis showed no prediction for BMD by postoperative CCD or stem type. In conclusion, there was no clinically-relevant influence on proximal femur BMD according to varus/valgus implantation of the Nanos® or Metha® prostheses.

Oxidation of octylphenol by ferrate(VI).

PubMed

Anquandah, George A K; Sharma, Virender K

2009-01-01

The rates of the oxidation of octylphenols (OP) by potassium ferrate(VI) (K(2)FeO(4)) in water were determined as a function of pH (8.0-10.9) at 25 degrees C. The rate law for the oxidation of OP by Fe(VI) was found to be first order with each reactant. The observed second-order rate constants, k(obs), for the oxidation of alkylphenols decreased with an increase in pH. The speciation of Fe(VI) (HFeO(4)(-) and FeO(4)(2 -)) and OP (OP-OH and OP-O(-)) species were used to determine individual rate constants of the reactions. Comparison of rate constants and half-lives of oxidation of OP by Fe(VI) with nonylphenol (NP) and bisphenol-A (BPA) were conducted to demonstrate that Fe(VI) efficiently oxidizes environmentally relevant alkylphenols in water.

The biomineralization process of uranium(VI) by Saccharomyces cerevisiae - transformation from amorphous U(VI) to crystalline chernikovite.

PubMed

Shen, Yanghao; Zheng, Xinyan; Wang, Xiaoyu; Wang, Tieshan

2018-05-01

Microorganisms play a significant role in uranium(VI) biogeochemistry and influence U(VI) transformation through biomineralization. In the present work, the process of uranium mineralization was investigated by Saccharomyces cerevisiae. The toxicity experiments showed that the viability of cell was not significantly affected by 100 mg L -1 U(VI) under 4 days of exposure time. The batch experiments showed that the phosphate concentration and pH value increased over time during U(VI) adsorption. Meanwhile, thermodynamic calculations demonstrated that the adsorption system was supersaturated with respect to UO 2 HPO 4 . The X-ray powder diffraction spectroscopy (XRD), field emission scanning electron microscopy (FE-SEM) equipped with energy dispersive spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS) analyses indicated that the U(VI) was first attached onto the cell surface and reacted with hydroxyl, carboxyl, and phosphate groups through electrostatic interactions and complexation. As the immobilization of U(VI) transformed it from the ionic to the amorphous state, lamellar uranium precipitate was formed on the cell surface. With the prolongation of time, the amorphous uranium compound disappeared, and there were some crystalline substances observed extracellularly, which were well-characterized as tetragonal-chernikovite. Furthermore, the size of chernikovite was regulated at nano-level by cells, and the perfect crystal was formed finally. These findings provided an understanding of the non-reductive transformation process of U(VI) from the amorphous to crystalline state within microbe systems, which would be beneficial for the U(VI) treatment and reuse of nuclides and heavy metals.

Change in First Metatarsal Length After Proximal and Distal Chevron Osteotomies for Hallux Valgus Deformity.

PubMed

Lee, Jun Young; Lee, Yeon Soo; Song, Kyoung Chul; Choi, Kwi Youn

2015-01-01

The present study assessed the changes in the length of the first metatarsal bone after performing proximal chevron metatarsal osteotomy (PCMO) or distal Chevron metatarsal osteotomy (DCMO) for patients with hallux valgus deformity. A total of 60 patients with moderate-to-severe hallux valgus deformity from July 2009 to July 2011 were randomly divided into the PCMO and DCMO groups, with 30 patients in each group. The distal soft tissue procedure was performed in the same method for both groups. Measurements were performed preoperatively, postoperatively, and at the last follow-up visit at 6.1 ± 0.8 months. The postoperative length change with respect to the preoperative length was 0.7 ± 2.5 mm and -0.7 ± 5.1 mm for the PCMO and DCMO groups, respectively, with a slight lengthening of the first metatarsal bone in the PCMO group and a shortening in the DCMO group (p < .01). The follow-up length change with respect to the preoperative length was -2.1 ± 3.0 mm and -4.4 ± 2.2 mm for the PCMO and DCMO groups, respectively, demonstrating a clear shortening of the first metatarsal length at the last follow-up point in the DCMO group (p < .01).When DCMO and the distal soft tissue procedure were performed, significant shortening was found at 6 months of follow-up. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

L'ostéotomie de scarf dans le traitement de l'hallux valgus: à propos de 19 cas

PubMed Central

Boussakri, Hassan; Bachiri, Mohammed; Elidrissi, Mohammed; Shimi, Mohammed; Elibrahimi, Abdelhalim; Elmrini, Abdelmajid

2014-01-01

L'ostéotomie de Scarf constitue une technique chirurgicale bien décrite, grâce à ses résultats excellents, elle est considérée comme un traitement de choix de l'hallux valgus. Le but de ce travail est de décrire le profil épidémiologique et radio-clinique des hallux valgus, ainsi qu’évaluer les résultats radiologiques et fonctionnels des patients traités par la technique classique d'ostéotomie de Scarf. Nous avons mené une étude rétrospective, concernant 22 ostéotomies de Scarf chez 19 patients, opérés d'hallux valgus entre mai 2009 et janvier 2013. Le recul moyen était de 22,5 mois (3-42 mois). L'âge moyen des patients au moment de l'intervention était de 49 ans, avec des extrêmes de 19 et 75 ans. Tous les patients ont bénéficié d'une évaluation clinique et radiologique préopératoire et postopératoire ainsi qu'une analyse statistique. Au dernier recul, selon des critères subjectifs, nos résultats étaient très satisfaisants dans 42%, satisfaisants dans 52% et déçus dans 6%, et en fonction du score de l'AOFAS, les résultats étaient nettement améliorée avec un AOFAS préopératoire de 57% à 84% en postopératoire. Concernant les résultats radiologiques, la déformation métatarsophalangienne (angle M1P1) a été corrigée (43,63 °-12,8°) avec une p très significative (p <0,001). D'autre part une amélioration de l'Angle moyen M1M2, passer de 18,18° préopératoire à 12,95° au dernier recul, avec une correction significative (p <0,001). Le valgus épiphysaire de premier métatarsien (AADM) a été statistiquement amélioré (p <0,001), passer de 24,45° à 7,91°. Concernant les complications nous avons noté un cas de sepsis précoce superficiel géré par une antibiothérapie adaptée, deux cas de névrome et un cas d'ostéonécrose. Par contre on n'a pas noté aucune fracture per opératoire du premier métatarsien. Nous concluons que l'ostéotomie de Scarf est une technique reproductible fiable, en pleine �

Technology-derived storage solutions for stabilizing insulin in extreme weather conditions I: the ViViCap-1 device.

PubMed

Pfützner, Andreas; Pesach, Gidi; Nagar, Ron

2017-06-01

Injectable life-saving drugs should not be exposed to temperatures <4°C/39°F or >30°C/86°F. Frequently, weather conditions exceed these temperature thresholds in many countries. Insulin is to be kept at 4-8°C/~ 39-47°F until use and once opened, is supposed to be stable for up to 31 days at room temperature (exception: 42 days for insulin levemir). Extremely hot or cold external temperature can lead to insulin degradation in a very short time with loss of its glucose-lowering efficacy. Combined chemical and engineering solutions for heat protection are employed in ViViCap-1 for disposable insulin pens. The device works based on vacuum insulation and heat consumption by phase-change material. Laboratory studies with exposure of ViViCap-1 to hot outside conditions were performed to evaluate the device performance. ViViCap-1 keeps insulin at an internal temperature < 29°C/84.2°F for a minimum of 12 h without external power requirement, even when constantly exposed to an outside temperature of 37.8°C/100°F. Bringing the device into an ambient temperature < 26°C/78.8°F reverses the phase-change process and 'recharges' the device for further use. ViViCap-1 performed within its specifications. The small and convenient device maintains the efficacy and safety of using insulin even when carried under hot weather conditions.

The Vi conjugate typhoid vaccine is safe, elicits protective levels of IgG anti-Vi, and is compatible with routine infant vaccines.

PubMed

Thiem, Vu Dinh; Lin, Feng-Ying C; Canh, Do Gia; Son, Nguyen Hong; Anh, Dang Duc; Mao, Nguyen Duc; Chu, Chiayung; Hunt, Steven W; Robbins, John B; Schneerson, Rachel; Szu, Shousun C

2011-05-01

Typhoid fever remains a serious problem in developing countries. Current vaccines are licensed for individuals who are 5 years old or older. A conjugate of the capsular polysaccharide (CP) of Salmonella enterica serovar Typhi (Vi) bound to recombinant exoprotein A of Pseudomonas aeruginosa (Vi-rEPA) enhanced Vi immunogenicity and protected 2- to 5-year-olds in Vietnam. In this study, Vi-rEPA was evaluated for use in infants. A total of 301 full-term Vietnamese infants received Expanded Program on Immunization (EPI) vaccines alone or with Vi-rEPA or Haemophilus influenzae type b-tetanus toxoid conjugate (Hib-TT) at 2, 4, and 6 months and Vi-rEPA or Hib-TT alone at 12 months. Infants were visited 6, 24, and 48 h after each injection to monitor adverse reactions. Maternal, cord, and infant sera were assayed for IgG anti-Vi and for IgG antibodies to Hib CP and the diphtheria, tetanus, and pertussis toxins at 7, 12, and 13 months. No vaccine-related serious adverse reactions occurred. In the Vi-rEPA group, the IgG anti-Vi geometric mean (GM) increased from the cord level of 0.66 to 17.4 enzyme-linked immunosorbent assay units (EU) at 7 months, declined to 4.76 EU at 12 months, and increased to 50.1 EU 1 month after the 4th dose (95% of infants had levels of ≥ 3.5 EU, the estimated protective level). Controls had no increase of the IgG anti-Vi GM. Infants with cord anti-Vi levels of <3.5 EU responded with significantly higher IgG anti-Vi levels than those with levels of ≥ 3.5 EU. Anti-diphtheria, -tetanus, and -pertussis toxin levels were similar in all groups. Vi-rEPA was safe, induced protective anti-Vi levels, and was compatible with EPI vaccines, and it can be used in infants. High cord IgG anti-Vi levels partially suppressed infant responses to Vi-rEPA.

Factors Affecting Formation of Incomplete Vi Antibody in Mice

PubMed Central

Gaines, Sidney; Currie, Julius A.; Tully, Joseph G.

1965-01-01

Gaines, Sidney (Walter Reed Army Institute of Research, Washington, D.C.), Julius A. Currie, and Joseph G. Tully. Factors affecting formation of incomplete Vi antibody in mice. J. Bacteriol. 90:635–642. 1965.—Single immunizing doses of purified Vi antigen elicited complete and incomplete Vi antibodies in BALB/c mice, but only incomplete antibody in Cinnamon mice. Three of six other mouse strains tested responded like BALB/c mice; the remaining three, like Cinnamon mice. Varying the quantity of antigen injected or the route of administration failed to stimulate the production of detectable complete Vi antibody in Cinnamon mice. Such antibody was evoked in these animals by multiple injections of Vi antigen or by inoculating them with Vi-containing bacilli or Vi-coated erythrocytes. The early protection afforded by serum from Vi-immunized BALB/c mice coincided with the appearance of incomplete Vi antibody, 1 day prior to the advent of complete antibody. Persistence of incomplete as well as complete antibody in the serum of immunized mice was demonstrated for at least 56 days after injection of 10 μg of Vi antigen. Incomplete Vi antibody was shown to have blocking ability, in vitro bactericidal activity, and the capability of protecting mice against intracerebral as well as intraperitoneal challenge with virulent typhoid bacilli. Production of incomplete and complete Vi antibodies was adversely affected by immunization with partially depolymerized Vi antigens. PMID:16562060

Effect of uranium(VI) speciation on simultaneous microbial reduction of uranium(VI) and iron(III).

PubMed

Stewart, Brandy D; Amos, Richard T; Fendorf, Scott

2011-01-01

Uranium is a pollutant of concern to both human and ecosystem health. Uranium's redox state often dictates whether it will reside in the aqueous or solid phase and thus plays an integral role in the mobility of uranium within the environment. In anaerobic environments, the more oxidized and mobile form of uranium (UO2(2+) and associated species) may be reduced, directly or indirectly, by microorganisms to U(IV) with subsequent precipitation of UO. However, various factors within soils and sediments, such as U(VI) speciation and the presence of competitive electron acceptors, may limit biological reduction of U(VI). Here we examine simultaneous dissimilatory reduction of Fe(III) and U(VI) in batch systems containing dissolved uranyl acetate and ferrihydrite-coated sand. Varying amounts of calcium were added to induce changes in aqueous U(VI) speciation. The amount of uranium removed from solution during 100 h of incubation with S. putrefaciens was 77% in absence of Ca or ferrihydrite, but only 24% (with ferrihydrite) and 14% (without ferrihydrite) were removed for systems with 0.8 mM Ca. Dissimilatory reduction of Fe(III) and U(VI) proceed through different enzyme pathways within one type of organism. We quantified the rate coefficients for simultaneous dissimilatory reduction of Fe(III) and U(VI) in systems varying in Ca concecentration (0-0.8 mM). The mathematical construct, implemented with the reactive transport code MIN3P, reveals predominant factors controlling rates and extent of uranium reduction in complex geochemical systems.

Bilateral carpal valgus deformity in hand-reared cheetah cubs (Acinonyx jubatus).

PubMed

Bell, Katherine M; van Zyl, Malan; Ugarte, Claudia E; Hartman, Angela

2011-01-01

Four hand-reared cheetah cubs (Acinonyx jubatus) exhibited progressively severe bilateral valgus deformity of the carpi (CV) during the weaning period. Radiographs of the thoracic limbs suggested normal bone ossification, and serum chemistry was unremarkable. All affected cubs developed CV shortly after the onset of gastroenteritis, which was treated medically, and included use of a prescription diet. A sudden decrease in growth rate was associated with gastrointestinal disease. Before gastroenteritis and CV, affected cubs had higher growth rates than unaffected cubs, despite similar mean daily energy intake. Return to normal thoracic limb conformation was consequent to dietary manipulation (including a reduction in energy intake and vitamin and mineral supplementation), as well as decreased growth rates and recovery from gastroenteritis. The cause of the CV is likely to have been multi-factorial with potentially complex physiological interactions involved. © 2010 Wiley-Liss, Inc.

77 FR 52116 - Title VI; Final Circular

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-28

... DEPARTMENT OF TRANSPORTATION Federal Transit Administration [Docket No. FTA-2011-0054] Title VI... Web site, guidance in the form of a Circular to assist grantees in complying with Title VI of the... Title VI regulations (49 CFR part 21). DATES: Effective Date: The effective date of the Circular is...

Kinetic investigations of quinoline oxidation by ferrate(VI).

PubMed

Luo, Zhiyong; Li, Xueming; Zhai, Jun

2016-01-01

Quinoline is considered as one of the most toxic and carcinogenic compounds and is commonly found in industrial wastewaters, which require treatment before being discharged. Removal of quinoline by the use of an environmentally friendly oxidant, potassium ferrate(VI) (K2FeO4), was assessed by studying the kinetics of the oxidation of quinoline by ferrate(VI) (Fe(VI)) as a function of pH (8.53-10.53) and temperature (21-36°C) in this work. The reaction of quinoline with Fe(VI) was found to be first order in Fe(VI), half order in quinoline, and 1.5 order overall. The observed rate constant at 28°C decreased non-linearly from 0.5334 to 0.2365 M(-0.5) min(-1) with an increase in pH from 8.53 to 10.03. Considering the equilibria of Fe(VI) and quinoline, the reaction between quinoline and Fe(VI) contained two parallel reactions under the given pH conditions. The individual rate constants of these two reactions were determined. The results indicate that the protonated species of Fe(VI) reacts more quickly with quinoline than the deprotonated form of Fe(VI). The reaction activation energy Ea was obtained to be 51.44 kJ·mol(-1), and it was slightly lower than that of conventional chemical reaction. It reveals that the oxidation of quinoline by Fe(VI) is feasible in the routine water treatment.

Identifying the need for a multidisciplinary approach for early recognition of mucopolysaccharidosis VI (MPS VI).

PubMed

Choy, Yew Sing; Bhattacharya, Kaustuv; Balasubramaniam, Shanti; Fietz, Michael; Fu, Antony; Inwood, Anita; Jin, Dong-Kyu; Kim, Ok-Hwa; Kosuga, Motomichi; Kwun, Young Hee; Lin, Hsiang-Yu; Lin, Shuan-Pei; Mendelsohn, Nancy J; Okuyama, Torayuki; Samion, Hasri; Tan, Adeline; Tanaka, Akemi; Thamkunanon, Verasak; Thong, Meow-Keong; Toh, Teck-Hock; Yang, Albert D; McGill, Jim

2015-05-01

Mucopolysaccharidosis VI (MPS VI, Maroteaux-Lamy syndrome) is caused by deficient activity of the enzyme, N-acetylgalactosamine-4-sulfatase, resulting in impaired degradation of the glycosaminoglycan dermatan sulfate. Patients experience a range of manifestations including joint contractures, short stature, dysostosis multiplex, coarse facial features, decreased pulmonary function, cardiac abnormalities, corneal clouding and shortened life span. Recently, clinicians from institutions in the Asia-Pacific region met to discuss the occurrence and implications of delayed diagnosis and misdiagnosis of MPS VI in the patients they have managed. Eighteen patients (44% female) were diagnosed. The most common sign presented by the patients was bone deformities in 11 patients (65%). Delays to diagnosis occurred due to the lack of or distance to diagnostic facilities for four patients (31%), alternative diagnoses for two patients (15%), and misleading symptoms experienced by two patients (15%). Several patients experienced manifestations that were subtler than would be expected and were subsequently overlooked. Several cases highlighted the unique challenges associated with diagnosing MPS VI from the perspective of different specialties and provide insights into how these patients initially present, which may help to elucidate strategies to improve the diagnosis of MPS VI. Copyright © 2015 Elsevier Inc. All rights reserved.

Immunization with the conjugate vaccine Vi-CRM₁₉₇ against Salmonella typhi induces Vi-specific mucosal and systemic immune responses in mice.

PubMed

Fiorino, Fabio; Ciabattini, Annalisa; Rondini, Simona; Pozzi, Gianni; Martin, Laura B; Medaglini, Donata

2012-09-21

Typhoid fever is a public health problem, especially among young children in developing countries. To address this need, a glycoconjugate vaccine Vi-CRM₁₉₇, composed of the polysaccharide antigen Vi covalently conjugated to the non-toxic mutant of diphtheria toxin CRM₁₉₇, is under development. Here, we assessed the antibody and cellular responses, both local and systemic, following subcutaneous injection of Vi-CRM₁₉₇. The glycoconjugate elicited Vi-specific serum IgG titers significantly higher than unconjugated Vi, with prevalence of IgG1 that persisted for at least 60 days after immunization. Vi-specific IgG, but not IgA, were present in intestinal washes. Lymphocytes proliferation after restimulation with Vi-CRM₁₉₇ was observed in spleen and mesenteric lymph nodes. These data confirm the immunogenicity of Vi-CRM₁₉₇ and demonstrate that the vaccine-specific antibody and cellular immune responses are present also in the intestinal tract, thus strengthening the suitability of Vi-CRM₁₉₇ as a promising candidate vaccine against Salmonella Typhi. Copyright © 2012 Elsevier Ltd. All rights reserved.

A comparison of Chevron and Lindgren-Turan osteotomy techniques in hallux valgus surgery: a prospective randomized controlled study.

PubMed

Uygur, Esat; Özkan, Namık Kemal; Akan, Kaya; Çift, Hakan

2016-01-01

The aim of this prospective randomized controlled single-blind study was to compare the results of Chevron and Lindgren-Turan osteotomy techniques for treatment of moderate hallux valgus. A total of 66 female patients (34 in Chevron group, 32 Lindgren-Turan group) were recruited in this study and followed up for an average of 26.08 months. Operative procedures were performed by 2 surgeons, and patients were evaluated by an another researcher who was blinded to the surgical technique. The groups were compared for their radiological and clinical results. Both techniques was clinically and radiologically effective (p<0.01). However, no significant differences were found between the 2 groups regarding American Orthopaedic Foot and Ankle Society's clinical rating system, Painful Foot Evaluation scale of Maryland University scores, or radiologic evaluation (p>0.05). Compared to the Chevron group, the Lindgren-Turan group was found to have shorter surgical duration (p<0.05) and significantly more shortening at the first metatarsal (p<0.05). In moderate hallux valgus deformity, both the Chevron and Lindgren-Turan osteotomy techniques are clinically and radiologically safe, effective, and reliable alternatives. No superiority was detected in either technique. Although shortening at the first metatarsal in the Lindgren-Turan group was radiologically significant, the results were clinically tolerable.

Electrochemical alkaline Fe(VI) water purification and remediation.

PubMed

Licht, Stuart; Yu, Xingwen

2005-10-15

Fe(VI) is an unusual and strongly oxidizing form of iron, which provides a potentially less hazardous water-purifying agent than chlorine. A novel on-line electrochemical Fe(VI) water purification methodology is introduced. Fe(VI) addition had been a barrier to its effective use in water remediation, because solid Fe(VI) salts require complex (costly) syntheses steps and solutions of Fe(VI) decompose. Online electrochemical Fe(VI) water purification avoids these limitations, in which Fe(VI) is directly prepared in solution from an iron anode as the FeO42- ion, and is added to the contaminant stream. Added FeO42- decomposes, by oxidizing a wide range of water contaminants including sulfides (demonstrated in this study) and other sulfur-containing compounds, cyanides (demonstrated in this study), arsenic (demonstrated in this study), ammonia and other nitrogen-containing compounds (previously demonstrated), a wide range of organics (phenol demonstrated in this study), algae, and viruses (each previously demonstrated).

Assessment of medial elbow laxity by gravity stress radiography: comparison of valgus stress radiography with gravity and a Telos stress device.

PubMed

Harada, Mikio; Takahara, Masatoshi; Maruyama, Masahiro; Nemoto, Tadanobu; Koseki, Kazuhiko; Kato, Yoshihiro

2014-04-01

Valgus instability was reported to be higher with the elbow in 60° of flexion, rather than in 30° of flexion, although there are no studies using valgus stress radiography by gravity (gravity radiography) with the elbow in 60° of flexion. Fifty-seven patients with medial elbow pain participated. For both elbows, valgus stress radiography by use of a Telos device (Telos radiography) and gravity radiography, with the elbow in 60° of flexion, were performed for the assessment of medial elbow laxity. In both radiographs, the medial elbow joint space (MJS) on the affected side was compared with that on the opposite side, and the increase in the MJS on the affected side was assessed. For the Telos radiographs, the mean MJS was 4.7 mm on the affected side and 4.0 mm on the opposite side, with the mean increase in the MJS on the affected side being 0.7 mm. For the gravity radiographs, the mean MJS was 5.0 mm on the affected side and 4.2 mm on the opposite side, with the mean increase in the MJS on the affected side being 0.8 mm. There were significant correlations between the Telos and gravity radiographs in the MJS on the affected side, the MJS on the opposite side, and the increase in the MJS on the affected side (respectively, P < .0001). There was also a high level of intraobserver and interobserver reliability for the assessment of the gravity radiographs. Gravity radiography is useful for assessment of medial elbow laxity, similar to Telos radiography. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Immediate effect of valgus bracing on knee joint moments in meniscectomised patients: An exploratory study.

PubMed

Thorning, Maria; Thorlund, Jonas B; Roos, Ewa M; Wrigley, Tim V; Hall, Michelle

2016-12-01

Patients undergoing medial arthroscopic partial meniscectomy are at increased risk of developing and/or progressing knee osteoarthritis, with increased medial compartment load being a potential contributor. The aim of this study was to evaluate the immediate effect of a valgus unloader knee brace on knee joint moments in patients following medial arthroscopic partial meniscectomy. Within-participant design. Twenty-two patients (age 35-55 years) who had undergone medial arthroscopic partial meniscectomy within the previous 8-15 months completed three-dimensional analysis of gait, forward lunge and one-leg rise during two conditions: with and without a valgus unloader knee brace. Outcome measures included the peak and impulse of the knee adduction moment and the peak knee flexion moment. The peak knee flexion moment increased during brace condition for forward lunge (mean difference [95% CI]) 0.54 [0.27-0.82] (Nm/(BW×HT)%), p<0.001 and one-leg rise (mean difference 0.45 [95% CI 0.08-0.82] (Nm/(BW×HT)%), p=0.022). No other significant differences were found between conditions in any of the included tasks. A significant effect of the knee brace was detected in terms of an increase in peak knee flexion moment during the more demanding tasks such as forward lunge and one-leg rise. This increase implies enhanced stability of the knee provided by the brace, which may induce increased knee function and knee-related confidence during strenuous tasks. Future research is required to explore the structural implications. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Myosin VI facilitates connexin 43 gap junction accretion.

PubMed

Waxse, Bennett J; Sengupta, Prabuddha; Hesketh, Geoffrey G; Lippincott-Schwartz, Jennifer; Buss, Folma

2017-03-01

In this study, we demonstrate myosin VI enrichment at Cx43 (also known as GJA1)-containing gap junctions (GJs) in heart tissue, primary cardiomyocytes and cell culture models. In primary cardiac tissue and in fibroblasts from the myosin VI-null mouse as well as in tissue culture cells transfected with siRNA against myosin VI, we observe reduced GJ plaque size with a concomitant reduction in intercellular communication, as shown by fluorescence recovery after photobleaching (FRAP) and a new method of selective calcein administration. Analysis of the molecular role of myosin VI in Cx43 trafficking indicates that myosin VI is dispensable for the delivery of Cx43 to the cell surface and connexon movement in the plasma membrane. Furthermore, we cannot corroborate clathrin or Dab2 localization at gap junctions and we do not observe a function for the myosin-VI-Dab2 complex in clathrin-dependent endocytosis of annular gap junctions. Instead, we found that myosin VI was localized at the edge of Cx43 plaques by using total internal reflection fluorescence (TIRF) microscopy and use FRAP to identify a plaque accretion defect as the primary manifestation of myosin VI loss in Cx43 homeostasis. A fuller understanding of this derangement may explain the cardiomyopathy or gliosis associated with the loss of myosin VI. © 2017. Published by The Company of Biologists Ltd.

Biosorption of Cr(VI) by coconut coir: spectroscopic investigation on the reaction mechanism of Cr(VI) with lignocellulosic material.

PubMed

Shen, Ying-Shuian; Wang, Shan-Li; Huang, Shiuh-Tsuen; Tzou, Yu-Min; Huang, Jang-Hung

2010-07-15

In this study, the removal mechanism of Cr(VI) from water by coconut coir (CC) was investigated using X-ray photoelectron spectroscopy (XPS), Cr K-edge X-ray absorption near edge structure (XANES) and FTIR spectroscopy. The results showed that, upon reaction with CC at pH 3, Cr(VI) was reduced to Cr(III), which was either bound to CC or released back into solution. As revealed by the FTIR spectra of CC before and after reacting with Cr(VI), the phenolic methoxyl and hydroxyl groups of lignin in CC are the dominant drivers of Cr(VI) reduction, giving rise to carbonyl and carboxyl groups on CC. These functional groups can subsequently provide binding sites for Cr(III) resulting from Cr(VI) reduction. In conjunction with forming complexes with carbonyl and carboxyl groups, the formation of Cr(III) hydroxide precipitate could also readily occur as revealed by the linear combination fitting of the Cr K-edge XANES spectrum using a set of reference compounds. The phenolic groups in lignin are responsible for initiating Cr(VI) reduction, so lignocellulosic materials containing a higher amount of phenolic groups are expected to be more effective scavengers for removal of Cr(VI) from the environment. 2010 Elsevier B.V. All rights reserved.

[PERSONALIZED DISTAL FEMORAL VALGUS RESECTION ANGLE IN PRIMARY TOTAL KNEE ARTHROPLASTY].

PubMed

Wang, Xilong; Shang, Xifu; Ll, Guoyuan; He, Rui; Zheng, Jie

2015-01-01

To investigate the feasibility and effectiveness of a personalized distal femoral valgus resection angle for improving postoperative coronal alignment of lower limb in total knee arthroplasty (TKA). A retrospective analysis was made on the clinical data of 50 patients who received primary TKA between January 2013 and February 2013. There were 11 male and 39 female patients with degenerative knee osteoarthritis. The patients were divided into 2 groups. In test group (n=25), the resection angle was adjusted to the femoral mechanical anatomical angle (FMA); in control group (n=25), a fixed distal valgus resection angle of 5° was used. There was no significant difference in gender, age, body mass index, disease duration, sides, grade, preoperative FMA, mechanical femorotibial angle (MFT), and preoperative Knee Society Score (KSS) between 2 groups (P > 0.05). Whole long X-ray film was taken to measure FMA and MFT at 3 days after operation, postoperative KSS was used to evaluate the knee function after 6 and 15 months. MFT was (-0.20 ± 1.87)° in test group and was (1.71 ± 3.67)° in control group, showing significant difference between 2 groups (t = 2.32, P = 0.02). The ideal MFT angle (0 ± 3)° was achieved in 22 patients (88%) of test group and in 16 patients (64%) of control group, showing significant difference between 2 groups (χ2 = 2.32, P = 0.02). Primary healing of incision was obtained in all patients of 2 groups. No deep venous thrombosis occurred. The patients of 2 groups were followed up 15 months after operation. There was significant difference in KSS between test and control groups at 6 months (88.23 ± 2.57 vs. 82.92 ± 2.59) (t = 7.26, P = 0.00) and at 15 months (90.76 ± 2.77 vs. 88.65 ± 1.77) (t = 3.20, P = 0.02). No sign of prosthesis loosening was observed by X-ray examination. Compared with using of a fixed distal femoral resection angle, an individual FMA can significantly improve the postoperative MFT and promote early recovery of the knee

Title VI Summary 2000-2001.

ERIC Educational Resources Information Center

Huskey, Barton

Title VI provides federal funds to states under the Elementary and Secondary Education Act of 1965. This document describes Title VI programs and the use of funds in the Austin Independent School District (AISD), Texas for 2000-2001. The AISD allocation of $481,559 was based on the May 2000 projected school enrollment, including projected…

The adsorption behavior of U(VI) on granite.

PubMed

Fan, Q H; Hao, L M; Wang, C L; Zheng, Z; Liu, C L; Wu, W S

2014-03-01

The effects of pH, counter ions and temperature on the adsorption of U(VI) on Beishan granite (BsG) were investigated in the presence and absence of fulvic acid (FA) and humic acid (HA). The adsorption edge of U(VI) on BsG suggested that U(VI) adsorption was mainly controlled by ion exchange and outer-sphere complexation at low pH, whereas inner-sphere complex was the dominant adsorption species in the pH range of 4.0-9.0. Above pH 9.0, Na2U2O7 might play an important role in the rise of U(VI) adsorption again. Counter ions such as Cl(-), SO4(2-) and PO4(3-) can provoke U(VI) adsorption on BsG to some extent, which was directly correlated to the complexing ability of U(VI)-ligand. More noticeably, the large enhancement of U(VI) adsorption in the presence of phosphate can be attributed to the ternary complex formation (BsG-PO4-UO2), precipitation ((UO2)3(PO4)2(s)) and secondary phase (Na-autunite). Both FA and HA can slightly increase U(VI) adsorption at low pH, whereas they strongly inhibited U(VI) adsorption at high pH range. Artificial synthesized granite (AsG) prepared in the laboratory is impossible to use as an analogue of natural granite because of the large difference in the adsorption and surface properties.

Reactivity of nitrido complexes of ruthenium(VI), osmium(VI), and manganese(V) bearing Schiff base and simple anionic ligands.

PubMed

Man, Wai-Lun; Lam, William W Y; Lau, Tai-Chu

2014-02-18

Nitrido complexes (M≡N) may be key intermediates in chemical and biological nitrogen fixation and serve as useful reagents for nitrogenation of organic compounds. Osmium(VI) nitrido complexes bearing 2,2':6',2″-terpyridine (terpy), 2,2'-bipyridine (bpy), or hydrotris(1-pyrazolyl)borate anion (Tp) ligands are highly electrophilic: they can react with a variety of nucleophiles to generate novel osmium(IV)/(V) complexes. This Account describes our recent results studying the reactivity of nitridocomplexes of ruthenium(VI), osmium(VI), and manganese(V) that bear Schiff bases and other simple anionic ligands. We demonstrate that these nitrido complexes exhibit rich chemical reactivity. They react with various nucleophiles, activate C-H bonds, undergo N···N coupling, catalyze the oxidation of organic compounds, and show anticancer activities. Ruthenium(VI) nitrido complexes bearing Schiff base ligands, such as [Ru(VI)(N)(salchda)(CH3OH)](+) (salchda = N,N'-bis(salicylidene)o-cyclohexyldiamine dianion), are highly electrophilic. This complex reacts readily at ambient conditions with a variety of nucleophiles at rates that are much faster than similar reactions using Os(VI)≡N. This complex also carries out unique reactions, including the direct aziridination of alkenes, C-H bond activation of alkanes and C-N bond cleavage of anilines. The addition of ligands such as pyridine can enhance the reactivity of [Ru(VI)(N)(salchda)(CH3OH)](+). Therefore researchers can tune the reactivity of Ru≡N by adding a ligand L trans to nitride: L-Ru≡N. Moreover, the addition of various nucleophiles (Nu) to Ru(VI)≡N initially generate the ruthenium(IV) imido species Ru(IV)-N(Nu), a new class of hydrogen-atom transfer (HAT) reagents. Nucleophiles also readily add to coordinated Schiff base ligands in Os(VI)≡N and Ru(VI)≡N complexes. These additions are often stereospecific, suggesting that the nitrido ligand has a directing effect on the incoming nucleophile. M≡N is also

Ferrate(VI) oxidation of cyanide in water.

PubMed

Costarramone, N; Kneip, A; Castetbon, A

2004-08-01

Experiments were conducted to test removal of cyanide (free cyanide and several cyanide complexes) in water, under alkaline medium (pH > or = 11), by a new potassium ferrate salt. The removal rate of free cyanide by oxidation with Fe(VI) was greater at pH 11.0 than at pH 12.0. A complete oxidation was obtained with a 2.67 Fe(VI)/CN ratio at pH 11.0. In these conditions, the rate of cyanide oxidation by Fe(VI) was slow, with a reaction rate constant estimated at 0.95 +/- 0.10 s(-1) l mol(-1) at pH 11.0 and 19.6 degrees C in this study. This study revealed that Fe(VI) did not decompose all cyanide complexes. Copper, cadmium and zinc complexes were removed efficiently by Fe(VI). Moreover, these metals were also removed from the solution by coagulation effect of Fe(OH)3, the Fe(VI) product of reaction. A particular behaviour was reported with copper, as a rapid oxidation of cyanide was observed in the presence of this metal. On the contrary, oxidation of nickel and silver complexes was incomplete.

Mechanisms of chromium (VI)-induced apoptosis in anterior pituitary cells.

PubMed

Quinteros, Fernanda A; Machiavelli, Leticia I; Miler, Eliana A; Cabilla, Jimena P; Duvilanski, Beatriz H

2008-07-30

Hexavalent chromium (Cr (VI)) is a highly toxic metal. Exposure to Cr (VI) compounds may affect reproductive functions. Due to the importance of anterior pituitary hormones on reproductive physiology we have studied the effects of Cr (VI) on anterior pituitary. We previously demonstrated that, after in vivo Cr (VI) administration, Cr accumulates in the pituitary gland and affects prolactin secretion. In vitro, Cr (VI) causes apoptosis in anterior pituitary cells due to oxidative stress generation. To better understand the mechanisms involved in Cr (VI)-induced apoptosis we studied: (a) whether Cr (VI) affects the intracellular antioxidant response and (b) which of the apoptotic factors participates in Cr (VI) effect. Our results show that Cr (VI) treatment induces a decrease in catalase and glutathione peroxidase (GPx) activity but does not modify glutathione reductase (GR) activity. Cr (VI) exposure causes an increase of GSH levels. p53 and Bax mRNA are also upregulated by the metal. Pifithrin alpha, a p53 transcriptional inhibitor, increases Cr (VI) cytotoxicity, suggesting a role of p53 as a survival molecule. The antioxidant N-acetyl-cysteine (NAC) could prevent Bax mRNA increase and caspase 3 activation, confirming that Cr (VI)-induced apoptosis involves oxidative stress generation.

Emissions of chromium (VI) from arc welding.

PubMed

Heung, William; Yun, Myoung-Jin; Chang, Daniel P Y; Green, Peter G; Halm, Chris

2007-02-01

The presence of Cr in the +6 oxidation state (Cr[VI]) is still observed in ambient air samples in California despite steps taken to reduce emissions from plating operations. One known source of emission of Cr(VI) is welding, especially with high Cr-content materials, such as stainless steels. An experimental effort was undertaken to expand and update Cr(VI) emission factors by conducting tests on four types of arc-welding operations: gas-metal arc welding (GMAW), shielded metal arc welding (SMAW), fluxcore arc welding, and pulsed GMAW. Standard American Welding Society hood results were compared with a total enclosure method that permitted isokinetic sampling for particle size-cut measurement, as well as total collection of the aerosol. The fraction of Cr(VI) emitted per unit mass of Cr electrode consumed was determined. Consistent with AP-42 data, initial results indicate that a significant fraction of the total Cr in the aerosol is in the +6 oxidation state. The fraction of Cr(VI) and total aerosol mass produced by the different arc welding methods varies with the type of welding process used. Self-shielded electrodes that do not use a shield gas, for example, SMAW, produce greater amounts of Cr(VI) per unit mass of electrode consumed. The formation of Cr(VI) from standard electrode wires used for welding mild steel was below the method detection limit after eliminating an artifact in the analytical method used.

Wound healing complications in patients with and without systemic diseases following hallux valgus surgery.

PubMed

Kromuszczyńska, Justyna; Kołodziej, Łukasz; Jurewicz, Alina

2018-01-01

There are many defined risk factors for wound healing. Comorbidities and their treatment are identified to be one of them. The aim of this study is to verify whether there are significant differences in wound healing between patients with and without systemic diseases, who underwent hallux valgus correction with Scarf osteotomy. A total of 155 consecutive patients were included into this prospective study. All of the patients underwent Scarf osteotomy for hallux valgus correction. In 60,6% of patients comorbidities were present, most often hypertension (57 patients, 36,8%), hypothyroidism (19 patients 12,3%) and diabetes (7 patients, 4,5%) occurred. Most of the patients were women (96,1%). During the study complication rate was noted. Patients underwent follow-up: 1,2, 3, 6 and 12 weeks and 6 months after the surgery. Preoperatively and during the last visit treatment results were assessed with AOFAS HMI scale. Scar assessment was performed by independent observer with VAS followed by patient scar assessment with VSS. In 30 patients complications were noted (19,4%). Surgical site infection was found in 6 patients (3,9%). In 13 patients (8,4%) partial wound dehiscence occurred, in 5 of them (3,2%) additional skin closure (Steri-Strips) was applied. Treatment results assessed with AOFAS HMI scale were good and very good in both healthy and comorbidity group, and the results improved significantly after surgical procedure. Scar assessment with VAS was on the average 1,5 pts. Average result in VSS was 2 pts. Results in both scales were rated as very good. No statistically significant differences were found in both healthy and comorbidity group in scar assessment. Based on the results of the study authors believe there are no significant differences between patients with and without comorbidities in aspects like: complication rate, surgery result and scar assessment as long as foot surgery is concerned.

ETS-VI multibeam satellite communications systems

NASA Astrophysics Data System (ADS)

Kawai, Makoto; Tanaka, Masayoshi; Ohtomo, Isao

1989-10-01

The fixed and mobile satellite communications systems of the Japanese Engineering Test Satellite-VI (ETS-VI) are described. The system requirements are outlined along with the system configuration. The ETS-VI multibeam system employs three frequency bands. When used for Ka-band fixed communications, it covers the Japanese main islands with thirteen 0.3-degree-wide spot beam. Four of the beams are active for ETS-VI. When used for S-band mobile communications, five beams cover the area within 200 nautical miles from the Japanese coast. The C-band beam for fixed communications covers the central area of the Japanese main islands with a single beam. The onboard antenna system is described along with the transponders and their associated onboard systems. A discussion of the system technology follows, covering the TDMA transmisssion system, the relay function, rainfall compensation, and the antenna and propagation performance.

Hallux Valgus Deformity and Treatment: A Three-Dimensional Approach: Modified Technique for Lapidus Procedure.

PubMed

Santrock, Robert D; Smith, Bret

2018-06-01

In a hallux valgus deformity, the problem is deviation of the hallux at the metatarsophalangeal joint and of the first metatarsal at the tarsometatarsal joint. Although anterior-posterior radiograph findings have been prioritized, deviation in the other planes can substantially change visible cues. The modified technique for Lapidus procedure procedure, uses all 3 planes to evaluate and correct the deformity, making radiographic measurements less useful. Using a triplane framework and focusing on the apex of the deformity, all bunions become the same modified technique for Lapidus procedure can be performed regardless of the degree of deformity, always includes triplane correction, and deformity size becomes irrelevant. Copyright © 2018 Elsevier Inc. All rights reserved.

Point-Connecting Measurements of the Hallux Valgus Deformity: A New Measurement and Its Clinical Application

PubMed Central

Seo, Jeong-Ho; Boedijono, Dimas

2016-01-01

Purpose The aim of this study was to investigate new point-connecting measurements for the hallux valgus angle (HVA) and the first intermetatarsal angle (IMA), which can reflect the degree of subluxation of the first metatarsophalangeal joint (MTPJ). Also, this study attempted to compare the validity of midline measurements and the new point-connecting measurements for the determination of HVA and IMA values. Materials and Methods Sixty feet of hallux valgus patients who underwent surgery between 2007 and 2011 were classified in terms of the severity of HVA, congruency of the first MTPJ, and type of chevron metatarsal osteotomy. On weight-bearing dorsal-plantar radiographs, HVA and IMA values were measured and compared preoperatively and postoperatively using both the conventional and new methods. Results Compared with midline measurements, point-connecting measurements showed higher inter- and intra-observer reliability for preoperative HVA/IMA and similar or higher inter- and intra-observer reliability for postoperative HVA/IMA. Patients who underwent distal chevron metatarsal osteotomy (DCMO) had higher intraclass correlation coefficient for inter- and intra-observer reliability for pre- and post-operative HVA and IMA measured by the point-connecting method compared with the midline method. All differences in the preoperative HVAs and IMAs determined by both the midline method and point-connecting methods were significant between the deviated group and subluxated groups (p=0.001). Conclusion The point-connecting method for measuring HVA and IMA in the subluxated first MTPJ may better reflect the severity of a HV deformity with higher reliability than the midline method, and is more useful in patients with DCMO than in patients with proximal chevron metatarsal osteotomy. PMID:26996576

Vi-da: vitiligo diagnostic assistance mobile application

NASA Astrophysics Data System (ADS)

Nugraha, G. A.; Nurhudatiana, A.; Bahana, R.

2018-03-01

Vitiligo is a skin disorder in which white patches of depigmentation appear on different parts of the body. Usually, patients come to hospitals or clinics to have their vitiligo conditions assessed. This can be very tiring to the patients, as vitiligo treatments usually take a relatively long period of time, which can range from months to years. To address this challenge, we present in this paper a prototype of an Android-based mobile application called Vi-DA, which stands for Vitiligo Diagnostic Assistance. Vi-DA consists of three subsystems, which are user sign-up subsystem, camera and image analysis subsystem, and progress report subsystem. The mobile application was developed in Java programming language and uses MySQL as the database system. Vi-DA adopts a vitiligo segmentation algorithm to segment input image into normal skin area, vitiligo skin area, and non-skin area. Results showed that Vi-DA gave comparable results to the previous system implemented in Matlab. User acceptance testing results also showed that all respondents agreed on the usefulness of the system and agreed to use Vi-DA again in the future. Vi-DA benefits both dermatologists and patients as not only a computer-aided diagnosis (CAD) tool but also as a smart application that can be used for self-assessment at home.

ViA: a perceptual visualization assistant

NASA Astrophysics Data System (ADS)

Healey, Chris G.; St. Amant, Robert; Elhaddad, Mahmoud S.

2000-05-01

This paper describes an automated visualized assistant called ViA. ViA is designed to help users construct perceptually optical visualizations to represent, explore, and analyze large, complex, multidimensional datasets. We have approached this problem by studying what is known about the control of human visual attention. By harnessing the low-level human visual system, we can support our dual goals of rapid and accurate visualization. Perceptual guidelines that we have built using psychophysical experiments form the basis for ViA. ViA uses modified mixed-initiative planning algorithms from artificial intelligence to search of perceptually optical data attribute to visual feature mappings. Our perceptual guidelines are integrated into evaluation engines that provide evaluation weights for a given data-feature mapping, and hints on how that mapping might be improved. ViA begins by asking users a set of simple questions about their dataset and the analysis tasks they want to perform. Answers to these questions are used in combination with the evaluation engines to identify and intelligently pursue promising data-feature mappings. The result is an automatically-generated set of mappings that are perceptually salient, but that also respect the context of the dataset and users' preferences about how they want to visualize their data.

Cranial mononeuropathy VI

MedlinePlus

... palsy; Cranial nerve VI palsy; Sixth nerve palsy; Neuropathy - sixth nerve ... with: Brain aneurysms Nerve damage from diabetes( diabetic neuropathy ) Gradenigo syndrome (which also causes discharge from the ...

Uranium(VI) Reduction by Anaeromyxobacter dehalogenans Strain 2CP-C

PubMed Central

Wu, Qingzhong; Sanford, Robert A.; Löffler, Frank E.

2006-01-01

Previous studies demonstrated growth of Anaeromyxobacter dehalogenans strain 2CP-C with acetate or hydrogen as the electron donor and Fe(III), nitrate, nitrite, fumarate, oxygen, or ortho-substituted halophenols as electron acceptors. In this study, we explored and characterized U(VI) reduction by strain 2CP-C. Cell suspensions of fumarate-grown 2CP-C cells reduced U(VI) to U(IV). More-detailed growth studies demonstrated that hydrogen was the required electron donor for U(VI) reduction and could not be replaced by acetate. The addition of nitrate to U(VI)-reducing cultures resulted in a transitory increase in U(VI) concentration, apparently caused by the reoxidation of reduced U(IV), but U(VI) reduction resumed following the consumption of N-oxyanions. Inhibition of U(VI) reduction occurred in cultures amended with Fe(III) citrate, or citrate. In the presence of amorphous Fe(III) oxide, U(VI) reduction proceeded to completion but the U(VI) reduction rates decreased threefold compared to control cultures. Fumarate and 2-chlorophenol had no inhibitory effects on U(VI) reduction, and both electron acceptors were consumed concomitantly with U(VI). Since cocontaminants (e.g., nitrate, halogenated compounds) and bioavailable ferric iron are often encountered at uranium-impacted sites, the metabolic versatility makes Anaeromyxobacter dehalogenans a promising model organism for studying the complex interaction of multiple electron acceptors in U(VI) reduction and immobilization. PMID:16672509

23 CFR 200.7 - FHWA Title VI policy.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false FHWA Title VI policy. 200.7 Section 200.7 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.7 FHWA Title VI policy. It is the policy of the FHWA to...

23 CFR 200.7 - FHWA Title VI policy.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false FHWA Title VI policy. 200.7 Section 200.7 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.7 FHWA Title VI policy. It is the policy of the FHWA to...

23 CFR 200.7 - FHWA Title VI policy.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false FHWA Title VI policy. 200.7 Section 200.7 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.7 FHWA Title VI policy. It is the policy of the FHWA to...

23 CFR 200.7 - FHWA Title VI policy.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false FHWA Title VI policy. 200.7 Section 200.7 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.7 FHWA Title VI policy. It is the policy of the FHWA to...

Replication profile of Saccharomyces cerevisiae chromosome VI.

PubMed

Friedman, K L; Brewer, B J; Fangman, W L

1997-11-01

An understanding of the replication programme at the genome level will require the identification and characterization of origins of replication through large, contiguous regions of DNA. As a step toward this goal, origin efficiencies and replication times were determined for 10 ARSs spanning most of the 270 kilobase (kb) chromosome VI of Saccharomyces cerevisiae. Chromosome VI shows a wide variation in the percentage of cell cycles in which different replication origins are utilized. Most of the origins are activated in only a fraction of cells, suggesting that the pattern of origin usage on chromosome VI varies greatly within the cell population. The replication times of fragments containing chromosome VI origins show a temporal pattern that has been recognized on other chromosomes--the telomeres replicate late in S phase, while the central region of the chromosome replicates early. As demonstrated here for chromosome VI, analysis of the direction of replication fork movement along a chromosome and determination of replication time by measuring a period of hemimethylation may provide an efficient means of surveying origin activity over large regions of the genome.

1. COMPARISON OF PLANS, SHOWING KONGENSGADE 6 (see photograph VI50 ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. COMPARISON OF PLANS, SHOWING KONGENSGADE 6 (see photograph VI-50 50-2 for elevation), KONGENSGADE 8 (see photograph VI-50-3 for elevation), KONGENSGADE 9 (see photograph VI-50-3 for elevation), KONGENSGADE 17 (see photograph VI-50-5 for elevation), KONGENSGADE 56 (see photograph VI-50-8 for elevation), & KONGENSGADE 57 (see photograph VI-50-9 for elevation) - King Street Area Study, Kongensgade 5-18, 36, 37B, 51-58 (Houses), 5-18, 36-37B, 51-58 King Street, Frederiksted, St. Croix, VI

A numerical simulation approach to studying anterior cruciate ligament strains and internal forces among young recreational women performing valgus inducing stop-jump activities.

PubMed

Kar, Julia; Quesada, Peter M

2012-08-01

Anterior cruciate ligament (ACL) injuries are commonly incurred by recreational and professional women athletes during non-contact jumping maneuvers in sports like basketball and volleyball, where incidences of ACL injury is more frequent to females compared to males. What remains a numerical challenge is in vivo calculation of ACL strain and internal force. This study investigated effects of increasing stop-jump height on neuromuscular and bio-mechanical properties of knee and ACL, when performed by young female recreational athletes. The underlying hypothesis is increasing stop-jump (platform) height increases knee valgus angles and external moments which also increases ACL strain and internal force. Using numerical analysis tools comprised of Inverse Kinematics, Computed Muscle Control and Forward Dynamics, a novel approach is presented for computing ACL strain and internal force based on (1) knee joint kinematics and (2) optimization of muscle activation, with ACL insertion into musculoskeletal model. Results showed increases in knee valgus external moments and angles with increasing stop-jump height. Increase in stop-jump height from 30 to 50 cm lead to increase in average peak valgus external moment from 40.5 ± 3.2 to 43.2 ± 3.7 Nm which was co-incidental with increase in average peak ACL strain, from 9.3 ± 3.1 to 13.7 ± 1.1%, and average peak ACL internal force, from 1056.1 ± 71.4 to 1165.4 ± 123.8 N for the right side with comparable increases in the left. In effect this study demonstrates a technique for estimating dynamic changes to knee and ACL variables by conducting musculoskeletal simulation on motion analysis data, collected from actual stop-jump tasks performed by young recreational women athletes.

Comparison of distal soft-tissue procedures combined with a distal chevron osteotomy for moderate to severe hallux valgus: first web-space versus transarticular approach.

PubMed

Park, Yu-Bok; Lee, Keun-Bae; Kim, Sung-Kyu; Seon, Jong-Keun; Lee, Jun-Young

2013-11-06

There are two surgical approaches for distal soft-tissue procedures for the correction of hallux valgus-the dorsal first web-space approach, and the medial transarticular approach. The purpose of this study was to compare the outcomes achieved after use of either of these approaches combined with a distal chevron osteotomy in patients with moderate to severe hallux valgus. One hundred and twenty-two female patients (122 feet) who underwent a distal chevron osteotomy as part of a distal soft-tissue procedure for the treatment of symptomatic unilateral moderate to severe hallux valgus constituted the study cohort. The 122 feet were randomly divided into two groups: namely, a dorsal first web-space approach (group D; sixty feet) and a medial transarticular approach (group M; sixty-two feet). The clinical and radiographic results of the two groups were compared at a mean follow-up time of thirty-eight months. The American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot scale hallux metatarsophalangeal-interphalangeal scores improved from a mean and standard deviation of 55.5 ± 12.8 points preoperatively to 93.5 ± 6.3 points at the final follow-up in group D and from 54.9 ± 12.6 points preoperatively to 93.6 ± 6.2 points at the final follow-up in group M. The mean hallux valgus angle in groups D and M was reduced from 32.2° ± 6.3° and 33.1° ± 8.4° preoperatively to 10.5° ± 5.5° and 9.9° ± 5.5°, respectively, at the time of final follow-up. The mean first intermetatarsal angle in groups D and M was reduced from 15.0° ± 2.8° and 15.3° ± 2.7° preoperatively to 6.5° ± 2.2° and 6.3° ± 2.4°, respectively, at the final follow-up. The clinical and radiographic outcomes were not significantly different between the two groups. The final clinical and radiographic outcomes between the two approaches for distal soft-tissue procedures were comparable and equally successful. Accordingly, the results of this study suggest that the medial transarticular

29 CFR 1915.1026 - Chromium (VI).

Code of Federal Regulations, 2010 CFR

2010-07-01

... present from skin or eye contact with chromium (VI), the employer shall provide appropriate personal... clothing and equipment should be laundered or cleaned in a manner that minimizes skin or eye contact with... shall provide change rooms in conformance with 29 CFR 1910.141. Where skin contact with chromium (VI...

Characterization of Amoeba proteus myosin VI immunoanalog.

PubMed

Dominik, Magdalena; Kłopocka, Wanda; Pomorski, Paweł; Kocik, Elzbieta; Redowicz, Maria Jolanta

2005-07-01

Amoeba proteus, the highly motile free-living unicellular organism, has been widely used as a model to study cell motility. However, molecular mechanisms underlying its unique locomotion and intracellular actin-based-only trafficking remain poorly understood. A search for myosin motors responsible for vesicular transport in these giant cells resulted in detection of 130-kDa protein interacting with several polyclonal antibodies against different tail regions of human and chicken myosin VI. This protein was binding to actin in the ATP-dependent manner, and immunoprecipitated with anti-myosin VI antibodies. In order to characterize its possible functions in vivo, its cellular distribution and colocalization with actin filaments and dynamin II during migration and pinocytosis were examined. In migrating amoebae, myosin VI immunoanalog localized to vesicular structures, particularly within the perinuclear and sub-plasma membrane areas, and colocalized with dynamin II immunoanalog and actin filaments. The colocalization was even more evident in pinocytotic cells as proteins concentrated within pinocytotic pseudopodia. Moreover, dynamin II and myosin VI immunoanalogs cosedimented with actin filaments, and were found on the same isolated vesicles. Blocking endogenous myosin VI immunoanalog with anti-myosin VI antibodies inhibited the rate of pseudopodia protrusion (about 19% decrease) and uroidal retraction (about 28% decrease) but did not affect cell morphology and the manner of cell migration. Treatment with anti-human dynamin II antibodies led to changes in directionality of amebae migration and affected the rate of only uroidal translocation (about 30% inhibition). These results indicate that myosin VI immunoanalog is expressed in protist Amoeba proteus and may be involved in vesicle translocation and cell locomotion.

40 CFR Appendix Vi to Part 266 - Stack Plume Rise

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Stack Plume Rise VI Appendix VI to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED... FACILITIES Pt. 266, App. VI Appendix VI to Part 266—Stack Plume Rise [Estimated Plume Rise (in Meters) Based...

19 CFR Annex Vi to Part 351 - Countervailing Investigations Timeline

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 3 2010-04-01 2010-04-01 false Countervailing Investigations Timeline VI Annex VI to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex VI Annex VI to Part 351—Countervailing Investigations Timeline ER19MY97.000 ...

19 CFR Annex Vi to Part 351 - Countervailing Investigations Timeline

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 3 2013-04-01 2013-04-01 false Countervailing Investigations Timeline VI Annex VI to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex VI Annex VI to Part 351—Countervailing Investigations Timeline ER19MY97.000 ...

19 CFR Annex Vi to Part 351 - Countervailing Investigations Timeline

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 3 2014-04-01 2014-04-01 false Countervailing Investigations Timeline VI Annex VI to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex VI Annex VI to Part 351—Countervailing Investigations Timeline ER19MY97.000 ...

19 CFR Annex Vi to Part 351 - Countervailing Investigations Timeline

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 3 2012-04-01 2012-04-01 false Countervailing Investigations Timeline VI Annex VI to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex VI Annex VI to Part 351—Countervailing Investigations Timeline ER19MY97.000 ...

19 CFR Annex Vi to Part 351 - Countervailing Investigations Timeline

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 3 2011-04-01 2011-04-01 false Countervailing Investigations Timeline VI Annex VI to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex VI Annex VI to Part 351—Countervailing Investigations Timeline ER19MY97.000 ...

40 CFR Appendix Vi to Part 266 - Stack Plume Rise

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Stack Plume Rise VI Appendix VI to Part 266 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED... FACILITIES Pt. 266, App. VI Appendix VI to Part 266—Stack Plume Rise [Estimated Plume Rise (in Meters) Based...

Lengthening of the shortened first metatarsal after Wilson's osteotomy for hallux valgus.

PubMed

Singh, D; Dudkiewicz, I

2009-12-01

Metatarsalgia is a recognised complication following iatrogenic shortening of the first metatarsal in the management of hallux valgus. The traditional surgical treatment is by shortening osteotomies of the lesser metatarsals. We describe the results of lengthening of iatrogenic first brachymetatarsia in 16 females. A Scarf-type osteotomy was used in the first four cases and a step-cut of equal thicknesses along the axis of the first metatarsal was performed in the others. The mean follow-up was 21 months (19 to 26). Relief of metatarsalgia was obtained in the six patients in whom 10 mm of lengthening had been achieved, compared to only 50% relief in those where less than 8 mm of lengthening had been gained. One-stage step-cut lengthening osteotomy of the first metatarsal may be preferable to shortening osteotomies of the lesser metatarsals in the treatment of metatarsalgia following surgical shortening of the first metatarsal.

Plantar pressures determinants in mild Hallux Valgus.

PubMed

Martínez-Nova, Alfonso; Sánchez-Rodríguez, Raquel; Pérez-Soriano, Pedro; Llana-Belloch, Salvador; Leal-Muro, Alejo; Pedrera-Zamorano, Juan Diego

2010-07-01

While podobarometric techniques have been applied to the study of pressures in Hallux Valgus (HV), little is known about its clinical and radiological determinants. So, the aim of the present study was to determine the plantar pressure pattern in participants with mild HV, comparing to a control group, and their clinical and anthropometric determinants. Biofoot/IBV(®) in-shoe system was used to evaluate 79 participants with mild HV. Computerized measurements of the 1st intermetatarsal angle (IMA) and the hallux abductus angle (HAA) were made on antero-posterior radiographs. The clinical outcome was assessed using the AOFAS score. The dependent baropodometric variables and the independent clinical and anthropometric variables were subjected to a multiple regression analysis. In both groups, the highest average pressure was in the 2nd metatarsal head (MTH). The mean pressure under the Hallux was significantly higher in HV group (controls, 146.5±92.5kPa; HV, 328.5±113.2kPa; p<0.001). An 18.6% of average pressure under the 1st MTH was accounted for pain, first ray alignment and total AOFAS score. Variations of the HAA explained 26.8% of the mean Hallux pressure. Women with mild HV present with pathologically increased pressure under the Hallux, which is caused by the altered alignment of the first ray. Pain and clinical result were associated with the pressure under the 1st MTH and the remaining variables were only moderate predictors of dynamic plantar pressures. Copyright © 2010 Elsevier B.V. All rights reserved.

Dynamics of Chromium(VI) Removal from Drinking Water by Iron Electrocoagulation.

PubMed

Pan, Chao; Troyer, Lyndsay D; Catalano, Jeffrey G; Giammar, Daniel E

2016-12-20

The potential for new U.S. regulations for Cr(VI) in drinking water have spurred strong interests in improving technologies for Cr(VI) removal. This study examined iron electrocoagulation for Cr(VI) removal at conditions directly relevant to drinking water treatment. Cr(VI) is chemically reduced to less soluble Cr(III) species by the Fe(II) produced from an iron anode, and XANES spectra indicate that the Cr is entirely Cr(III) in solid-phases produced in electrocoagulation. The dynamics of Cr(VI) removal in electrocoagulation at pH 6 and pH 8 at both oxic and anoxic conditions can be described by a new model that incorporates Fe(II) release from the anode and heterogeneous and homogeneous reduction of Cr(VI) by Fe(II). Heterogeneous Cr(VI) reduction by adsorbed Fe(II) was critical to interpreting Cr(VI) removal at pH 6, and the Fe- and Cr-containing EC product was found to catalyze the redox reaction. Dissolved oxygen (DO) did not observably inhibit Cr(VI) removal because Fe(II) reacts with DO more slowly than it does with Cr(VI), and Cr(VI) removal was faster at higher pH. Even in the presence of common groundwater solutes, iron electrocoagulation lowered Cr(VI) concentrations to levels well below California's 10 μg/L.

Clinical and Radiological Outcomes Comparing Percutaneous Chevron-Akin Osteotomies vs Open Scarf-Akin Osteotomies for Hallux Valgus.

PubMed

Lai, Mun Chun; Rikhraj, Inderjeet Singh; Woo, Yew Lok; Yeo, William; Ng, Yung Chuan Sean; Koo, Kevin

2018-03-01

Minimally invasive surgeries have gained popularity due to less soft tissue trauma and better wound healing. To date, limited studies have compared the outcomes of percutaneous and open osteotomies. This study aims to investigate the clinical and radiological outcomes of percutaneous chevron-Akin osteotomies vs open scarf-Akin osteotomies at 24-month follow-up. We reviewed a prospectively collected database in a tertiary hospital hallux valgus registry. Twenty-nine feet that underwent a percutaneous technique were matched to 58 feet that underwent open scarf and Akin osteotomies. Clinical outcome measures assessed included visual analog scale (VAS) scores, American Orthopaedic Foot & Ankle Society Hallux Metatarsophalangeal-Interphalangeal score (AOFAS Hallux MTP-IP), and Short Form 36 (SF-36) Health Survey. Radiological outcomes included hallux valgus angle (HVA) and intermetatarsal angle (IMA). All patients were prospectively followed up at 6 and 24 months. Both groups showed comparable clinical and radiological outcomes at the 24-month follow-up. However, the percutaneous group demonstrated less pain in the perioperative period ( P < .001). There were significant differences in the change in HVA between the groups but comparable radiological outcomes in IMA at the 24-month follow-up. The percutaneous group demonstrated shorter length of operation ( P < .001). There were no complications in the percutaneous group but 3 wound complications in the open group. We conclude that clinical and radiological outcomes of third-generation percutaneous chevron-Akin osteotomies were comparable with open scarf and Akin osteotomies at 24 months but with significantly less perioperative pain, shorter length of operation, and less risk of wound complications. Level III, retrospective comparative series.

Kinetics of microbial reduction of Solid phase U(VI).

PubMed

Liu, Chongxuan; Jeon, Byong-Hun; Zachara, John M; Wang, Zheming; Dohnalkova, Alice; Fredrickson, James K

2006-10-15

Sodium boltwoodite (NaUO2SiO3OH x 1.5 H2O) was used to assess the kinetics of microbial reduction of solid-phase U(VI) by a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1. The bioreduction kinetics was studied with Na-boltwoodite in suspension or within alginate beads in a nongrowth medium with lactate as electron donor at pH 6.8 buffered with PIPES. Concentrations of U(VI)tot and cell number were varied to evaluate the coupling of U(VI) dissolution, diffusion, and microbial activity. Microscopic and spectroscopic analyses with transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and laser-induced fluorescence spectroscopy (LIFS) collectively indicated that solid-phase U(VI) was first dissolved and diffused out of grain interiors before it was reduced on bacterial surfaces and/or within the periplasm. The kinetics of solid-phase U(VI) bioreduction was well described by a coupled model of bicarbonate-promoted dissolution of Na-boltwoodite, intragrain uranyl diffusion, and Monod type bioreduction kinetics with respect to dissolved U(VI) concentration. The results demonstrated that microbial reduction of solid-phase U(VI) is controlled by coupled biological, chemical, and physical processes.

Influence of calcium on microbial reduction of solid phase uranium(VI).

PubMed

Liu, Chongxuan; Jeon, Byong-Hun; Zachara, John M; Wang, Zheming

2007-08-15

The effect of calcium on the dissolution and microbial reduction of a representative solid phase uranyl [U(VI)], sodium boltwoodite (NaUO(2)SiO(3)OH . 1.5H(2)O), was investigated to evaluate the rate-limiting step of microbial reduction of the solid phase U(VI). Microbial reduction experiments were performed in a culture of a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1, in a bicarbonate medium with lactate as electron donor at pH 6.8 buffered with PIPES. Calcium increased the rate of Na-boltwoodite dissolution and U(VI) bioavailability by increasing its solubility through the formation of a ternary aqueous calcium-uranyl-carbonate species. The ternary species, however, decreased the rates of microbial reduction of aqueous U(VI). Laser-induced fluorescence spectroscopy (LIFS) and transmission electron microscopy (TEM) collectively revealed that microbial reduction of solid phase U(VI) was a sequentially coupled process of Na-boltwoodite dissolution, U(VI) aqueous speciation, and microbial reduction of dissolved U(VI) to U(IV) that accumulated on bacterial surfaces/periplasm. Under studied experimental conditions, the overall rate of microbial reduction of solid phase U(VI) was limited by U(VI) dissolution reactions in solutions without calcium and limited by microbial reduction in solutions with calcium. Generally, the overall rate of microbial reduction of solid phase U(VI) was determined by the coupling of solid phase U(VI) dissolution, U(VI) aqueous speciation, and microbial reduction of dissolved U(VI) that were all affected by calcium. (c) 2007 Wiley Periodicals, Inc.

40 CFR Appendixes Vi-Vii to Part 600 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false [Reserved] VI Appendixes VI-VII to Part 600 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND CARBON-RELATED EXHAUST EMISSIONS OF MOTOR VEHICLES Appendixes VI-VII to Part 600 [Reserved] ...

40 CFR Appendixes Vi-Vii to Part 600 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false [Reserved] VI Appendixes VI-VII to Part 600 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND CARBON-RELATED EXHAUST EMISSIONS OF MOTOR VEHICLES Appendixes VI-VII to Part 600 [Reserved] ...

Lack of Collagen VI Promotes Wound-Induced Hair Growth.

PubMed

Chen, Peiwen; Cescon, Matilde; Bonaldo, Paolo

2015-10-01

Collagen VI is an extracellular matrix molecule that is abundantly expressed in the skin. However, the role of collagen VI in hair follicle growth is unknown. Here, we show that collagen VI is strongly deposited in hair follicles, and is markedly upregulated by skin wounding. Lack of collagen VI in Col6a1(-/-) mice delays hair cycling and growth under physiological conditions, but promotes wound-induced hair regrowth without affecting skin regeneration. Conversely, addition of purified collagen VI rescues the abnormal wound-induced hair regrowth in Col6a1(-/-) mice. Mechanistic studies revealed that the increased wound-induced hair regrowth of Col6a1(-/-) mice is triggered by activation of the Wnt/β-catenin signaling pathway, and is abolished by inhibition of this pathway. These findings highlight the essential relationships between extracellular matrix (ECM) and hair follicle regeneration, and suggest that collagen VI could be a potential therapeutic target for hair loss and other skin-related diseases.

Prospective comparative study of two methods for fixation after distal femur corrective osteotomy for valgus deformity; retrograde intramedullary nailing versus less invasive stabilization system plating.

PubMed

Özcan, Çağrı; Sökücü, Sami; Beng, Kubilay; Çetinkaya, Engin; Demir, Bilal; Kabukçuoğlu, Yavuz Selim

2016-10-01

The aim of this study was to compare the radiological and functional results of two different methods of fixation for the correction of femoral valgus deformities. Patients who had undergone osteotomy and correction of a valgus deformity from 2007 to 2013 were prospectively followed. Thirty three patients (20 females, 13 males) with 39 lower limbs were included in the study. Seventeen lower limbs were treated with retrograde intramedullary nailing (IMN) and 22 with less invasive stabilization system plating. Standing orthoroentgenograms of the lower limbs were taken pre-operatively and at the final follow-up. mLDFA, aLDFA, mechanical axis deviation (MAD) were measured in this orthoroentgenograms. Knee osteoarthritis outcome score (KOOS) and knee range of motion were used pre-operatively and at the final follow-up as part of the evaluation of the clinical results. All patients duration of surgery, length of hospital stay were assessed. Operations were performed by two orthopedic surgeons. The choice of correction method for each patient was determined by the surgeon. Pre-operative and post-operative values were simultaneously measured by two additional orthopedic surgeons. The mean age of the patients was 26.2 years (18.0-51.0) in the plating group and 29.3 years (18.0-55.0) in the nailing group. Patients in the plating and nailing groups were followed up for 24.0 (12.0-60.0) and 27.8 (12.0-60.0) months. All patients were followed for a minimum of 12 months. No significant differences were observed between the groups in terms of age, sex, or duration of follow-up (p > 0.05) Comparison of the pre- and post-operative mLDFA, aLDFA, MAD, length of hospital stay, and duration of surgery between the plating group and nailing group, no significant difference was observed between the groups (p > 0.05). However, patients treated with retrograde IMN had significantly better post-operative results in terms of the KOOS and range of motion of the knee according to

Trigonal Cu2-II-Sn-VI4 (II = Ba, Sr and VI = S, Se) quaternary compounds for earth-abundant photovoltaics.

PubMed

Hong, Feng; Lin, Wenjun; Meng, Weiwei; Yan, Yanfa

2016-02-14

We propose trigonal Cu2-II-Sn-VI4 (II = Ba, Sr and VI = S, Se) quaternary compounds for earth-abundant solar cell applications. Through density functional theory calculations, we show that these compounds exhibit similar electronic and optical properties to kesterite Cu2ZnSnS4 (CZTS): high optical absorption with band gaps suitable for efficient single-junction solar cell applications. However, the trigonal Cu2-II-Sn-VI4 compounds exhibit defect properties more suitable for photovoltaic applications than those of CZTS. In CZTS, the dominant defects are the deep acceptors, Cu substitutions on Zn sites, which cause non-radiative recombination and limit the open-circuit voltages of CZTS solar cells. On the contrary, the dominant defects in trigonal Cu2-II-Sn-VI4 are the shallow acceptors, Cu vacancies, similar to those in CuInSe2. Our results suggest that the trigonal Cu2-II-Sn-VI4 quaternary compounds could be promising candidates for efficient earth-abundant thin-film solar cell and photoeletrochemical water-splitting applications.

New generation ion-imprinted nanocarrier for removal of Cr(VI) from wastewater

NASA Astrophysics Data System (ADS)

Uygun, Murat; Feyzioğlu, Esra; Özçalışkan, Emir; Caka, Müşerref; Ergen, Aygen; Akgöl, Sinan; Denizli, Adil

2013-08-01

The purpose of this study was to prepare a novel ion-imprinted nanoparticle to remove Cr(VI) ions from waste water. For this, Cr(VI) ions were complexed with 2-methacryloylamido histidine (MAH) and then Cr(VI)-imprinted poly(HEMAH) nanoparticles were synthesized by surfactant-free emulsion polymerization technique. The templates, Cr(VI) ions, were removed from the nanoparticles using 0.1 M of HNO3 solution. The specific surface area of the Cr(VI)-imprinted poly(HEMAH) nanoparticles was found to be 1,397.85 m2/g, and the particle size was calculated as 155.3 nm. These Cr(VI)-imprinted nanoparticles were used for the adsorption/desorption of Cr(VI) ions from its aqueous solutions. The effects of initial Cr(VI) concentration and medium pH on the Cr(VI) adsorption capacity were also studied. The maximum adsorbed amount of Cr(VI) on the imprinted nanoparticles was found to be 3,830.58 mg/g nanoparticle in pH 4.0. In order to investigate the selectivity of the imprinted nanoparticle, adsorption studies were repeated using Cr(III) ions. The selectivity results demonstrated that Cr(VI)-imprinted poly(HEMAH) nanoparticles showed high affinity for the Cr(VI) ions than Cr(III). The Cr(VI)-imprinted nanoparticles were used several times without decreasing their Cr(VI) adsorption capacities.

[Application of three-dimensional printing technology to design individual angle section on Chevron of hallux valgus osteotomy].

PubMed

Zhang, Yu-Hang; Bi, Da-Wei; Chen, Yi-Min; Zu, Gang; Ma, Hai-Tao

2018-03-25

To explore clinical application of three-dimensional printing technology to design individual angle section on Chevron of hallux valgus osteotomy. From May 2013 to May 2016, 47 patients(66 feet) with mild to moderate hallux valgus treated by Chevron osteotomy according to different preoperative design were divided into computer osteotomy group(group A) and traditional osteotomy group(group B). In group A, there were 25 patients (33 feet), including 4 males(5 feet) and 21 females(28 feet) with an average age of (47.88±6.08) years old, average weight IMA was (13.58±1.15) degree, AOFAS score was 59.00±5.86, and treated individual 3D printing technology to design operation scheme. While in group B, there were 22 patients (33 feet), including 3 males (3 feet) and 19 females (28 feet) with an average age of (48.16±6.16) years old, average weight IMA was(13.51±1.14) degree, AOFAS score was 60.67±5.85, and treated with osteotomy according to surgical experience. Operation time, blood loss, hospital stays, VAS score at 1 week after operation, wound healing and improvement of postoperative weight-bearing intermetatarsal angle(IMA) were compared between two groups, AOFAS score system was used to evaluate ankle function after surgery. There was no significant difference in following-up between group A 12.41±2.32 and group B 11.73±2.76. There was 1 patient in group B were excluded. Others perform good wounds healing on the first stage after operation. There were no significant differences in operation time, blood loss, hospital stays and VAS score at 1 week after operation( P <0.05); IMA in group A was (5.21±0.88)°, (6.42±0.85)° in group B, and had significant differences between two groups ( t =5.68, P <0.05). There was obvious meaning in AOFAS score between group A 88.15±5.19 and group B 82.90±5.01( t =4.14, P <0.05). Fourteen feet in group A obtained excellent results and 19 feet good, while 5 feet in group B obtained excellent results and 27 feet good

Rheology of water ices V and VI

USGS Publications Warehouse

Durham, W.B.; Stern, L.A.; Kirby, S.H.

1996-01-01

We have measured the mechanical strength (??) of pure water ices V and VI under steady state deformation conditions. Constant displacement rate compressional tests were conducted in a gas apparatus at confining pressures from 400 250 K. Ices V and VI are thus Theologically distinct but by coincidence have approximately the same strength under the conditions chosen for these experiments. To avoid misidentification, these tests are therefore accompanied by careful observations of the occurrences and characteristics of phase changes. One sample each of ice V and VI was quenched at pressure to metastably retain the high-pressure phase and the acquired deformation microstructures; X ray diffraction analysis of these samples confirmed the phase identification. Surface replicas of the deformed and quenched samples suggest that ice V probably deforms largely by dislocation creep, while ice VI deforms by a more complicated process involving substantial grain size reduction through recrystallization.

Do hip muscle weakness and dynamic knee valgus matter for the clinical evaluation and decision-making process in patients with patellofemoral pain?

PubMed

Rabelo, Nayra Deise Dos Anjos; Lucareli, Paulo Roberto Garcia

Patellofemoral pain is a very common musculoskeletal condition. In the last years, evidence regarding this disease increased exponentially. Although widely investigated, this problem still frustrates patients and clinicians for having an unfavorable prognosis. Some gaps still exist in the understanding and managing of patellofemoral pain. Numerous cross-sectional association studies show an association between gluteus muscular strength and dynamic knee valgus in patients with patellofemoral pain. In spite of this biological plausibility, many evidences challenge the direct relationship between these factors. Recent studies have concluded that women with patellofemoral pain show muscular weakness of the hip based on the cross-sectional studies, however prospective studies indicate that hip weakness cannot be considered a risk for development of patellofemoral pain. In addition, some clinical trials have demonstrated that strength training of the gluteal muscles promotes significant improvement in symptoms but not alter the kinematics of the patients with patellofemoral pain. These findings cast doubt on whether the cause of this condition is really being treated, whether all individuals suffering from patellofemoral pain present dynamic knee valgus or if this is a disturbance present in only a subgroup of patients and whether the strengthening of the hip musculature is an option to consider for prevention of patellofemoral pain. Certainly, more studies should be conducted to clarify the influence of mechanical patterns on this condition, but with the existing evidence so far, the importance given to these issues in the evaluation and clinical decision on treatment of these patients seems questionable. Therefore, this masterclass explores the understanding about patellofemoral pain, highlighting mainly the importance of muscular strength and dynamic knee valgus, as well as other possible factors that must be consider during the evaluation and the decision making in

Hydrocarbon oxidation by beta-halogenated dioxoruthenium(VI) porphyrin complexes: effect of reduction potential (RuVI/V) and C-H bond-dissociation energy on rate constants.

PubMed

Che, Chi-Ming; Zhang, Jun-Long; Zhang, Rui; Huang, Jie-Sheng; Lai, Tat-Shing; Tsui, Wai-Man; Zhou, Xiang-Ge; Zhou, Zhong-Yuan; Zhu, Nianyong; Chang, Chi Kwong

2005-11-18

beta-Halogenated dioxoruthenium(VI) porphyrin complexes [Ru(VI)(F(28)-tpp)O(2)] [F(28)-tpp=2,3,7,8,12,13, 17,18-octafluoro-5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato(2-)] and [Ru(VI)(beta-Br(8)-tmp)O(2)] [beta-Br(8)-tmp=2,3,7,8,12,13,17,18-octabromo-5,10,15,20- tetrakis(2,4,6-trimethylphenyl)porphyrinato(2-)] were prepared from reactions of [Ru(II)(por)(CO)] [por=porphyrinato(2-)] with m-chloroperoxybenzoic acid in CH(2)Cl(2). Reactions of [Ru(VI)(por)O(2)] with excess PPh(3) in CH(2)Cl(2) gave [Ru(II)(F(20)-tpp)(PPh(3))(2)] [F(20)-tpp=5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato(2-)] and [Ru(II)(F(28)-tpp)(PPh(3))(2)]. The structures of [Ru(II)(por)(CO)(H(2)O)] and [Ru(II)(por)(PPh(3))(2)] (por=F(20)-tpp, F(28)-tpp) were determined by X-ray crystallography, revealing the effect of beta-fluorination of the porphyrin ligand on the coordination of axial ligands to ruthenium atom. The X-ray crystal structure of [Ru(VI)(F(20)-tpp)O(2)] shows a Ru=O bond length of 1.718(3) A. Electrochemical reduction of [Ru(VI)(por)O(2)] (Ru(VI) to Ru(V)) is irreversible or quasi-reversible, with the E(p,c)(Ru(VI/V)) spanning -0.31 to -1.15 V versus Cp(2)Fe(+/0). Kinetic studies were performed for the reactions of various [Ru(VI)(por)O(2)], including [Ru(VI)(F(28)-tpp)O(2)] and [Ru(VI)(beta-Br(8)-tmp)O(2)], with para-substituted styrenes p-X-C(6)H(4)CH=CH(2) (X=H, F, Cl, Me, MeO), cis- and trans-beta-methylstyrene, cyclohexene, norbornene, ethylbenzene, cumene, 9,10-dihydroanthracene, xanthene, and fluorene. The second-order rate constants (k(2)) obtained for the hydrocarbon oxidations by [Ru(VI)(F(28)-tpp)O(2)] are up to 28-fold larger than by [Ru(VI)(F(20)-tpp)O(2)]. Dual-parameter Hammett correlation implies that the styrene oxidation by [Ru(VI)(F(28)-tpp)O(2)] should involve rate-limiting generation of a benzylic radical intermediate, and the spin delocalization effect is more important than the polar effect. The k(2) values for the oxidation of styrene and

Valgus osteotomy and repositioning and fixation with a dynamic hip screw and a 135º single-angled barrel plate for un-united and neglected femoral neck fractures.

PubMed

Gupta, Sameer; Kukreja, Sunil; Singh, Vivek

2014-04-01

To review the outcome of 60 patients who underwent valgus subtrochanteric osteotomy and its repositioning for un-united and neglected femoral neck fractures. 60 patients (mean age, 35 years) underwent valgus subtrochanteric osteotomy and repositioning of the osteotomy and fixation with a dynamic hip screw and a 135° single-angled barrel plate for closed un-united femoral neck fractures after failed internal fixation (n=27) or neglected (>3 weeks) fractures (n=33). The most common fracture type was transcervical (n=48), followed by subcapital (n=6) and basal (n=6). All patients had displaced femoral neck fractures (Garden types 3 and 4). According to the Pauwel angle, 45 fractures were type 2 (30º-70º) and 15 were type 3 (>70º). Patients were followed up for a mean of 3.5 (range, 2-7.5) years. The mean Pauwel angle of the fracture was corrected from 65° (range, 50°-89°) to 26° (range, 25°-28°). Bone union was achieved in 56 patients after a mean of 3.9 (range, 3-5.5) months. The mean Harris hip score improved from 65 to 87.5. Outcome was excellent in 30 patients, good in 24, and poor in 6. Four of the patients developed avascular necrosis; 2 of whom nonetheless achieved a good outcome. Valgus osteotomy and repositioning and fixation with a dynamic hip screw and a 135° single-angled barrel plate was effective treatment for un-united and neglected femoral neck fractures.

Surgical correction of bilateral metacarpophalangeal valgus with curved osteotomies and type II external skeletal fixation in a seven-month-old alpaca.

PubMed

Schoonover, Mike J; Whitfield, Chase T; Rochat, Mark C; Streeter, Robert N; Sippel, Kate

2016-09-20

To report the successful surgical correction of severe bilateral metacarpophalangeal valgus angular limb deformities in a seven-month-old intact male alpaca cria using curved osteotomies stabilized with type II external skeletal fixation. Using a 21 mm crescentic shaped oscillating saw blade, bilateral osteotomies were performed in the distal metaphyses of the fused third and fourth metacarpal bones to correct valgus angular limb deformity of the metacarpophalangeal joints. Axial alignment of each limb was achieved by medially rotating the distal metacarpus in the frontal plane along the curved osteotomies. The osteotomies were stabilized using type II external skeletal fixators. The alpaca was immediately weight-bearing following the surgical procedure and no to minimal lameness was observed during healing of the osteotomies. Evaluation at five and 10 months following the surgery demonstrated acceptable axial alignment in the left forelimb while moderate to severe varus deformity (overcorrection) was observed in the right. Curved osteotomy of the distal metacarpus stabilized with type II external skeletal fixation can provide a favourable outcome in older alpaca crias affected with metacarpophalangeal angular limb deformities. Placement of the distal transfixation pins relative to the metacarpal physes should be carefully evaluated as overcorrection is possible, especially if growthpotential remains in only one physis of the fused third and fourth metacarpal bones.

Oxidation of trimethoprim by ferrate(VI): kinetics, products, and antibacterial activity.

PubMed

Anquandah, George A K; Sharma, Virender K; Knight, D Andrew; Batchu, Sudha Rani; Gardinali, Piero R

2011-12-15

Kinetics, stoichiometry, and products of the oxidation of trimethoprim (TMP), one of the most commonly detected antibacterial agents in surface waters and municipal wastewaters, by ferrate(VI) (Fe(VI)) were determined. The pH dependent second-order rate constants of the reactions of Fe(VI) with TMP were examined using acid-base properties of Fe(VI) and TMP. The kinetics of reactions of diaminopyrimidine (DAP) and trimethoxytoluene (TMT) with Fe(VI) were also determined to understand the reactivity of Fe(VI) with TMP. Oxidation products of the reactions of Fe(VI) with TMP and DAP were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Reaction pathways of oxidation of TMP by Fe(VI) are proposed to demonstrate the cleavage of the TMP molecule to ultimately result in 3,4,5,-trimethoxybenzaldehyde and 2,4-dinitropyrimidine as among the final identified products. The oxidized products mixture exhibited no antibacterial activity against E. coli after complete consumption of TMP. Removal of TMP in the secondary effluent by Fe(VI) was achieved.

Kinetics of Microbial Reduction of Solid Phase U(VI)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Chongxuan; Jeon, Byong Hun; Zachara, John M.

2006-10-01

Sodium boltwoodite (NaUO2SiO3OH ?1.5H2O) was used to assess the kinetics of microbial reduction of solid phase U(VI) by a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1. The bioreduction kinetics was studied with Na-boltwoodite in suspension or within alginate beads. Concentrations of U(VI)tot and cell number were varied to evaluate the coupling of U(VI) dissolution, diffusion, and microbial activity. Batch experiments were performed in a non-growth medium with lactate as electron donor at pH 6.8 buffered with PIPES. Microscopic and spectroscopic analyses with transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), and laser-induced fluorescence spectroscopy (LIFS) collectively indicated that solidmore » phase U(VI) was first dissolved and diffused out of grain interiors before it was reduced on bacterial surfaces and/or within the periplasm. The kinetics of solid phase U(VI) bioreduction was well described by a coupled model of bicarbonate-promoted dissolution of Na-boltwoodite, intraparticle uranyl diffusion, and Monod type bioreduction kinetics with respect to dissolved U(VI) concentration. The results demonstrated the intimate coupling of biological, chemical, and physical processes in microbial reduction of solid phase U(VI).« less

The FUSE Survey of 0 VI in the Galactic Halo

NASA Technical Reports Server (NTRS)

Sonneborn, George; Savage, B. D.; Wakker, B. P.; Sembach, K. R.; Jenkins, E. B.; Moos, H. W.; Shull, J. M.

2003-01-01

This paper summarizes the results of the Far-Ultraviolet Spectroscopic Explorer (FUSE) program to study 0 VI in the Milky Way halo. Spectra of 100 extragalactic objects and two distant halo stars are analyzed to obtain measures of O VI absorption along paths through the Milky Way thick disk/halo. Strong O VI absorption over the velocity range from -100 to 100 km/s reveals a widespread but highly irregular distribution of O VI, implying the existence of substantial amounts of hot gas with T approx. 3 x 10(exp 5) K in the Milky Way thick disk/halo. The overall distribution of O VI is not well described by a symmetrical plane-parallel layer of patchy O VI absorption. The simplest departure from such a model that provides a reasonable fit to the observations is a plane-parallel patchy absorbing layer with an average O VI mid-plane density of n(sub 0)(O VI) = 1.7 x 10(exp -2)/cu cm, a scale height of approx. 2.3 kpc, and a approx. 0.25 dex excess of O VI in the northern Galactic polar region. The distribution of O VI over the sky is poorly correlated with other tracers of gas in the halo, including low and intermediate velocity H I, Ha emission from the warm ionized gas at approx. l0(exp 4) K, and hot X-ray emitting gas at approx. l0(exp 6) K . The O VI has an average velocity dispersion, b approx. 60 km/s and standard deviation of 15 km/s. Thermal broadening alone cannot explain the large observed profile widths. A combination of models involving the radiative cooling of hot fountain gas, the cooling of supernova bubbles in the halo, and the turbulent mixing of warm and hot halo gases is required to explain the presence of O VI and other highly ionized atoms found in the halo. The preferential venting of hot gas from local bubbles and superbubbles into the northern Galactic polar region may explain the enhancement of O VI in the North.

Design, baseline characteristics, and early findings of the MPS VI (mucopolysaccharidosis VI) Clinical Surveillance Program (CSP).

PubMed

Hendriksz, Christian J; Giugliani, Roberto; Harmatz, Paul; Lampe, Christina; Martins, Ana Maria; Pastores, Gregory M; Steiner, Robert D; Leão Teles, Elisa; Valayannopoulos, Vassili

2013-03-01

To outline the design, baseline data, and 5-year follow-up data of patients with mucopolysaccharidosis (MPS) VI enrolled in the Clinical Surveillance Program (CSP), a voluntary, multinational, observational program. The MPS VI CSP was opened in 2005 to collect, for at least 15 years, observational data from standard clinical and laboratory assessments of patients with MPS VI. Baseline and follow-up data are documented by participating physicians in electronic case report forms. Between September 2005 and March 2010 the CSP enrolled 132 patients, including 123 who received enzyme replacement therapy (ERT) with galsulfase. Median age at enrolment was 13 years (range 1-59). Mean baseline data showed impaired growth, hepatosplenomegaly, and reduced endurance and pulmonary function. The most common findings were heart valve disease (90%), reduced visual acuity (79%), impaired hearing (59%), and hepatosplenomegaly (54%). Follow-up data up to 5 years in patients with pre- and post-ERT measurements showed a decrease in urinary glycosaminoglycans and increases in height and weight in patients <16 years and suggested reductions in liver and spleen size and improvements in endurance and pulmonary function after ERT was started. Vision, hearing, and cardiac function were unchanged. Safety data were in line with previous reports. The CSP represents the largest cross-sectional study of MPS VI to date. This first report provides information on the design and implementation of the program and population statistics for several clinical variables in patients with MPS VI. Data collected over 5 years suggest that ERT provides clinical benefit and is well-tolerated with no new safety concerns.

Correction of static axial alignment in children with knee varus or valgus deformities through guided growth: Does it also correct dynamic frontal plane moments during walking?

PubMed

Böhm, Harald; Stief, Felix; Sander, Klaus; Hösl, Matthias; Döderlein, Leonhard

2015-09-01

Malaligned knees are predisposed to the development and progression of unicompartmental degenerations because of the excessive load placed on one side of the knee. Therefore, guided growth in skeletally immature patients is recommended. Indication for correction of varus/valgus deformities are based on static weight bearing radiographs. However, the dynamic knee abduction moment during walking showed only a weak correlation to malalignment determined by static radiographs. Therefore, the aim of the study was to measure the effects of guided growth on the normalization of frontal plane knee joint moments during walking. 15 legs of 8 patients (11-15 years) with idiopathic axial varus or valgus malalignment were analyzed. 16 typically developed peers served as controls. Instrumented gait analysis and clinical assessment were performed the day before implantation and explantation of eight-plates. Correlation between static mechanical tibiofemoral axis angle (MAA) and dynamic frontal plane knee joint moments and their change by guided growth were performed. The changes in dynamic knee moment in the frontal plane following guided growth showed high and significant correlation to the changes in static MAA (R=0.97, p<0.001). Contrary to the correlation of the changes, there was no correlation between static and dynamic measures in both sessions. In consequence two patients that had a natural knee moment before treatment showed a more pathological one after treatment. In conclusion, the changes in the dynamic load situation during walking can be predicted from the changes in static alignment. If pre-surgical gait analysis reveals a natural load situation, despite a static varus or valgus deformity, the intervention must be critically discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of a lower limb functional exercise programme aimed at minimising knee valgus angle on running kinematics in youth athletes.

PubMed

Sheerin, Kelly R; Hume, Patria A; Whatman, Chris

2012-11-01

To investigate the effectiveness of 8-weeks of lower limb functional exercises on frontal plane hip and knee angles during running in youth athletes. Pre- and post-intervention quantitative experimental. Nineteen athletes (11 male, 8 female, 11.54 ± 1.34 years) from a long-term athletic development programme had 3-dimensional running gait measured pre and post an 8-week exercise intervention. Youth athletes randomised to control (upper limb strengthening exercises) or experimental (lower limb functional exercises aimed at minimising knee valgus angle) interventions completed the exercises during the first 10 min of training, three mornings a week. Pre- and post-parallel groups' analysis provided estimates of intervention effects for control and experimental groups. Differences in pre- to post-intervention changes in mean frontal plane angles between control and experimental groups were trivial for the left hip (0.1°) and right knee (-0.3°). There was a small beneficial decrease in right hip joint angle (0.4°) but a very large (ES = 0.77, CI 0.1-3.7) detrimental increase in left knee valgus angle (1.9°) between groups. The 8-week lower limb functional exercises had little beneficial effects on lower limb hip and knee mechanics in youth athletes aged 9-14 years. Copyright © 2012 Elsevier Ltd. All rights reserved.

Modelling biological Cr(VI) reduction in aquifer microcosm column systems.

PubMed

Molokwane, Pulane E; Chirwa, Evans M N

2013-01-01

Several chrome processing facilities in South Africa release hexavalent chromium (Cr(VI)) into groundwater resources. Pump-and-treat remediation processes have been implemented at some of the sites but have not been successful in reducing contamination levels. The current study is aimed at developing an environmentally friendly, cost-effective and self-sustained biological method to curb the spread of chromium at the contaminated sites. An indigenous Cr(VI)-reducing mixed culture of bacteria was demonstrated to reduce high levels of Cr(VI) in laboratory samples. The effect of Cr(VI) on the removal rate was evaluated at concentrations up to 400 mg/L. Following the detailed evaluation of fundamental processes for biological Cr(VI) reduction, a predictive model for Cr(VI) breakthrough through aquifer microcosm reactors was developed. The reaction rate in batch followed non-competitive rate kinetics with a Cr(VI) inhibition threshold concentration of approximately 99 mg/L. This study evaluates the application of the kinetic parameters determined in the batch reactors to the continuous flow process. The model developed from advection-reaction rate kinetics in a porous media fitted best the effluent Cr(VI) concentration. The model was also used to elucidate the logistic nature of biomass growth in the reactor systems.

Diverse functions of myosin VI elucidated by an isoform-specific α-helix domain.

PubMed

Wollscheid, Hans-Peter; Biancospino, Matteo; He, Fahu; Magistrati, Elisa; Molteni, Erika; Lupia, Michela; Soffientini, Paolo; Rottner, Klemens; Cavallaro, Ugo; Pozzoli, Uberto; Mapelli, Marina; Walters, Kylie J; Polo, Simona

2016-04-01

Myosin VI functions in endocytosis and cell motility. Alternative splicing of myosin VI mRNA generates two distinct isoform types, myosin VI(short) and myosin VI(long), which differ in the C-terminal region. Their physiological and pathological roles remain unknown. Here we identified an isoform-specific regulatory helix, named the α2-linker, that defines specific conformations and hence determines the target selectivity of human myosin VI. The presence of the α2-linker structurally defines a new clathrin-binding domain that is unique to myosin VI(long) and masks the known RRL interaction motif. This finding is relevant to ovarian cancer, in which alternative myosin VI splicing is aberrantly regulated, and exon skipping dictates cell addiction to myosin VI(short) in tumor-cell migration. The RRL interactor optineurin contributes to this process by selectively binding myosin VI(short). Thus, the α2-linker acts like a molecular switch that assigns myosin VI to distinct endocytic (myosin VI(long)) or migratory (myosin VI(short)) functional roles.

32 CFR 2003.6 - Voting (Article VI).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 32 National Defense 6 2014-07-01 2014-07-01 false Voting (Article VI). 2003.6 Section 2003.6 National Defense Other Regulations Relating to National Defense INFORMATION SECURITY OVERSIGHT OFFICE...) BYLAWS, RULES, AND APPEAL PROCEDURES Bylaws § 2003.6 Voting (Article VI). (a) Motions. When the Panel is...

32 CFR 2003.6 - Voting (Article VI).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 32 National Defense 6 2013-07-01 2013-07-01 false Voting (Article VI). 2003.6 Section 2003.6 National Defense Other Regulations Relating to National Defense INFORMATION SECURITY OVERSIGHT OFFICE...) BYLAWS, RULES, AND APPEAL PROCEDURES Bylaws § 2003.6 Voting (Article VI). (a) Motions. When the Panel is...

Distribution and Kinematics of O VI in the Galactic Halo

NASA Astrophysics Data System (ADS)

Savage, B. D.; Sembach, K. R.; Wakker, B. P.; Richter, P.; Meade, M.; Jenkins, E. B.; Shull, J. M.; Moos, H. W.; Sonneborn, G.

2003-05-01

Far-Ultraviolet Spectroscopic Explorer (FUSE) spectra of 100 extragalactic objects and two distant halo stars are analyzed to obtain measures of O VI λλ1031.93, 1037.62 absorption along paths through the Milky Way thick disk/halo. Strong O VI absorption over the velocity range from -100 to 100 km s-1 reveals a widespread but highly irregular distribution of O VI, implying the existence of substantial amounts of hot gas with T~3×105 K in the Milky Way thick disk/halo. The integrated column density, log[N(O VI) cm-2], ranges from 13.85 to 14.78 with an average value of 14.38 and a standard deviation of 0.18. Large irregularities in the gas distribution are found to be similar over angular scales extending from <1° to 180°, implying a considerable amount of small- and large-scale structure in the absorbing gas. The overall distribution of O VI is not well described by a symmetrical plane-parallel layer of patchy O VI absorption. The simplest departure from such a model that provides a reasonable fit to the observations is a plane-parallel patchy absorbing layer with an average O VI midplane density of n0(O VI)=1.7×10-8 cm-3, a scale height of ~2.3 kpc, and a ~0.25 dex excess of O VI in the northern Galactic polar region. The distribution of O VI over the sky is poorly correlated with other tracers of gas in the halo, including low- and intermediate-velocity H I, Hα emission from the warm ionized gas at ~104 K, and hot X-ray-emitting gas at ~106 K. The O VI has an average velocity dispersion, b~60 km s-1, and standard deviation of 15 km s-1. Thermal broadening alone cannot explain the large observed profile widths. The average O VI absorption velocities toward high-latitude objects (|b|>45deg) range from -46 to 82 km s-1, with a high-latitude sample average of 0 km s-1 and a standard deviation of 21 km s-1. High positive velocity O VI absorbing wings extending from ~100 to ~250 km s-1 observed along 21 lines of sight may be tracing the flow of O VI into the halo

Degradation of chloramphenicol by potassium ferrate (VI) oxidation: kinetics and products.

PubMed

Zhou, Jia-Heng; Chen, Kai-Bo; Hong, Qian-Kun; Zeng, Fan-Cheng; Wang, Hong-Yu

2017-04-01

The oxidation of chloramphenicol (CAP) by potassium ferrate (VI) in test solution was studied in this paper. A series of jar tests were performed at bench scale with pH of 5-9 and molar ratio [VI/CAP] of 16.3:1-81.6:1. Results showed that raising VI dose could improve the treatment performance and the influence of solution pH was significant. VI is more reactive in neutral conditions, presenting the highest removal efficiency of CAP. The rate law for the oxidation of CAP by VI was first order with respect to each reactant, yielding an overall second-order reaction. Furthermore, five oxidation products were observed during CAP oxidation by VI. Results revealed that VI attacked the amide group of CAP, leading to the cleavage of the group, while benzene ring remained intact.

A Comparison of Two Designs of Postoperative Shoe on Function, Satisfaction, and Back Pain After Hallux Valgus Surgery.

PubMed

Patel, Shelain; Garg, Parag; Fazal, M Ali; Shahid, Muhammad S; Park, Derek H; Ray, Pinak S

2018-06-01

The reverse camber shoe is commonly used after hallux valgus corrective surgery to offload the forefoot but is associated with back pain and poor compliance. Recent designs of postoperative shoes may obviate the need for a reverse camber. The purpose of this study was to compare the effects of a reverse camber shoe and a noncambered shoe with transitional rigidity after hallux valgus correction. A cohort of 80 feet was prospectively studied undergoing surgery at a single NHS trust. The first 40 feet received the reverse cambered Jura Medical Off-loader Heel shoe and the subsequent 40 feet received the noncambered DonJoy Podalux shoe. No demographic differences existed between the groups and data were collected at 2 weeks, 6 weeks, and 6 months. The Manchester-Oxford Foot Questionnaire (MOXFQ), a 5-question survey and dichotomous question about back pain was used to assess clinical outcome and radiographs were reviewed by 2 orthopaedic surgeons to monitor for loss of correction. Both groups experienced comparable improvements in MOXFQ and shoe satisfaction from 2 weeks compared with 6 weeks. Six patients experienced back pain in the reverse cambered shoe group and none in the noncambered shoe group. Five patients stopped using the reverse cambered shoe during the first 6 weeks after surgery and none stopped using their prescribed noncambered shoe. No loss of corrections were observed in either group. Both shoe designs gave equal foot specific functional and radiological outcomes, but the noncambered shoe with transitional rigidity was associated with less back pain and better compliance. Level II: Prospective comparative study.

Effect of distal ulnar collateral ligament tear pattern on contact forces and valgus stability in the posteromedial compartment of the elbow.

PubMed

Hassan, Sheref E; Parks, Brent G; Douoguih, Wiemi A; Osbahr, Daryl C

2015-02-01

It is not known whether the pattern of ulnar collateral ligament (UCL) tear affects elbow biomechanics. There will be a significant change in elbow biomechanics with 50% proximal but not 50% distal simulated rupture of the UCL. Controlled laboratory study. Pressure sensors in the posteromedial elbow joint of 25 male cadaveric elbows (average age, 54.9 years; range, 26-66 years) were used to measure contact area, pressure, and valgus torque at 90° and 30° of elbow flexion. Thirteen specimens were tested with the UCL intact, then with proximal-to-distal detachment of 50%, and then with proximal-to-distal detachment of 100% of the anterior band of the UCL from the ulnar attachment. This method was repeated in the remaining 12 specimens in a distal-to-proximal direction. With 50% proximal-to-distal detachment, contact area decreased significantly versus intact at 90° (91.3 ± 23.6 vs 112.2 ± 26.0 mm(2); P < .001) and 30° (69.3 ± 14.8 vs 83.1 ± 21.6 mm(2); P < .001) of elbow flexion; the center of pressure (COP) moved significantly proximally versus intact at 90° (3.8 ± 2.5 vs 5.4 ± 2.3 mm; P < .001) and 30° (5.9 ± 2.8 vs 7.4±1.9 mm; P < .001). With 50% distal-to-proximal UCL detachment versus intact, no significant change was observed in contact area, movement of the COP, or valgus laxity at either flexion position. With 100% proximal-to-distal and distal-to-proximal detachment, significant change in contact area, movement of the COP, and valgus laxity versus intact was found at 90° and 30° of elbow flexion (P < .05). No significant difference in contact pressure was observed in any test conditions. Significant change in contact area and proximal movement of the COP with 50% proximal UCL detachment and the lack of significant change with 50% distal UCL detachment suggest that the proximal half of the UCL ulnar footprint has a primary role in maintaining posteromedial elbow biomechanics. The findings suggest that surgical reconstruction should aim to

Chromium(VI) generation in vadose zone soils and alluvial sediments of the southwestern Sacramento Valley, California: a potential source of geogenic Cr(VI) to groundwater

USGS Publications Warehouse

Mills, Christopher T.; Morrison, Jean M.; Goldhaber, Martin B.; Ellefsen, Karl J.

2011-01-01

Concentrations of geogenic Cr(VI) in groundwater that exceed the World Health Organization’s maximum contaminant level for drinking water (50 μg L−1) occur in several locations globally. The major mechanism for mobilization of this Cr(VI) at these sites is the weathering of Cr(III) from ultramafic rocks and its subsequent oxidation on Mn oxides. This process may be occurring in the southern Sacramento Valley of California where Cr(VI) concentrations in groundwater can approach or exceed 50 μg L−1. To characterize Cr geochemistry in the area, samples from several soil auger cores (approximately 4 m deep) and drill cores (approximately 25 m deep) were analyzed for total concentrations of 44 major, minor and trace elements, Cr associated with labile Mn and Fe oxides, and Cr(VI). Total concentrations of Cr in these samples ranged from 140 to 2220 mg per kg soil. Between 9 and 70 mg per kg soil was released by selective extractions that target Fe oxides, but essentially no Cr was associated with the abundant reactive Mn oxides (up to ~1000 mg hydroxylamine-reducible Mn per kg soil was present). Both borehole magnetic susceptibility surveys performed at some of the drill core sites and relative differences between Cr released in a 4-acid digestion versus total Cr (lithium metaborate fusion digestion) suggest that the majority of total Cr in the samples is present in refractory chromite minerals transported from ultramafic exposures in the Coast Range Mountains. Chromium(VI) in the samples studied ranged from 0 to 42 μg kg−1, representing a minute fraction of total Cr. Chromium(VI) content was typically below detection in surface soils (top 10 cm) where soil organic matter was high, and increased with increasing depth in the soil auger cores as organic matter decreased. Maximum concentrations of Cr(VI) were up to 3 times greater in the deeper drill core samples than the shallow auger cores. Although Cr(VI) in these vadose zone soils and sediments was only a

Stabilization of Cr(VI) from fine ferrochrome dust using exfoliated vermiculite.

PubMed

Mulange Wa Mulange, Delphin; Garbers-Craig, Andrie Mariana

2012-07-15

This study proved that vermiculite, a natural occurring mineral, can effectively remove and stabilize Cr(VI) from fine ferrochrome dust leachate. Batch adsorption studies were carried out to determine the effect of pH, contact time and adsorbent dose on the removal of Cr(VI). The process was found to be highly pH dependent. The optimum conditions for the Cr(VI) removal are at a pH of 1.5, contact time of 2h and adsorbent dose of 10gL(-1). The stability of the Cr(VI)-loaded vermiculite remained unchanged after 12 months, when the vermiculite was evaluated with the ASTM and TCLP Cr(VI) leach methods. However, Cr(VI) desorption did take place when the Acid Rain Test was used. The adsorption kinetic data fits the pseudo-second order model, while the equilibrium data of Cr(VI) adsorption onto vermiculite are best described by the Langmuir isotherm. The presence of hydrobiotite and biotite in the industrial vermiculite slightly decreased the degree of adsorption of Cr(VI). Copyright © 2012 Elsevier B.V. All rights reserved.

Cranial nerve VI palsy after dural-arachnoid puncture.

PubMed

Hofer, Jennifer E; Scavone, Barbara M

2015-03-01

In this article, we provide a literature review of cranial nerve (CN) VI injury after dural-arachnoid puncture. CN VI injury is rare and ranges in severity from diplopia to complete lateral rectus palsy with deviated gaze. The proposed mechanism of injury is cerebrospinal fluid leakage causing intracranial hypotension and downward displacement of the brainstem. This results in traction on CN VI leading to stretch and neural demyelination. Symptoms may present 1 day to 3 weeks after dural-arachnoid puncture and typically are associated with a postdural puncture (spinal) headache. Resolution of symptoms may take weeks to months. Use of small-gauge, noncutting spinal needles may decrease the risk of intracranial hypotension and subsequent CN VI injury. When ocular symptoms are present, early administration of an epidural blood patch may decrease morbidity or prevent progression of ocular symptoms.

Vi-CRM 197 as a new conjugate vaccine against Salmonella Typhi.

PubMed

Micoli, F; Rondini, S; Pisoni, I; Proietti, D; Berti, F; Costantino, P; Rappuoli, R; Szu, S; Saul, A; Martin, L B

2011-01-17

An efficacious, low cost vaccine against typhoid fever, especially for young children, would make a major impact on disease burden in developing countries. The virulence capsular polysaccharide of Salmonella Typhi (Vi) coupled to recombinant mutant Pseudomonas aeruginosa exoprotein A (Vi-rEPA) has been shown to be highly efficacious. We investigated the use of carrier proteins included in infant vaccines, standardized the conjugation process and developed key assays required for routine lot release at production scale. Vi from a BSL1 organism, Citrobacter freundii, strain WR7011, was used as an alternative to Vi from S. Typhi. We showed that Vi conjugated to CRM(197), a non-toxic mutant of diphtheria toxin, widely used in commercial vaccines, was produced at high yield. Vi-CRM(197) proved immunogenic in animal studies, even without adjuvant. Thus, Vi-CRM(197) appears to be a suitable candidate for the development of a commercially viable, effective typhoid vaccine for developing countries. Copyright © 2010 Elsevier Ltd. All rights reserved.

Forensic investigation of a chromium(VI) groundwater plume in Thiva, Greece.

PubMed

Panagiotakis, I; Dermatas, D; Vatseris, C; Chrysochoou, M; Papassiopi, N; Xenidis, A; Vaxevanidou, K

2015-01-08

A forensic investigation was conducted with the aim of decoupling the contribution of geogenic and anthropogenic Cr(VI) sources in the wider area of Thiva. Groundwater and topsoil samples were collected from two Cr(VI) groundwater plumes of 160 μg/L and 75 μg/L. A series of evidence support the view that the origin of Cr(VI) detected in groundwater is mainly geogenic. These are: (a) the presence of Cr in topsoil of the wider area, (b) the moderate Cr(VI) groundwater concentrations, (c) the high Ni levels within the Cr(VI) plumes, (d) the predominance of Mn(IV), which is a prerequisite for Cr(III) oxidation to Cr(VI), and (e) the absence of co-contaminants. The present study also revealed that, although both Cr(VI) plumes are clearly of geogenic origin, the plume with the elevated Cr(VI) values, in the north of Thiva town, exhibits also an anthropogenic component, which can potentially be attributed to the alkaline environment associated with the old uncontrolled landfill of Thiva and the industrial cluster located in this area. Copyright © 2014 Elsevier B.V. All rights reserved.

Influence of Calcium on Microbial Reduction of Solid Phase Uranium (VI)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Chongxuan; Jeon, Byong-Hun; Zachara, John M.

2007-06-27

The effect of calcium on microbial reduction of a solid phase U(VI), sodium boltwoodite (NaUO2SiO3OH ∙1.5H2O), was evaluated in a culture of a dissimilatory metal-reducing bacterium (DMRB), Shewanella oneidensis strain MR-1. Batch experiments were performed in a non-growth bicarbonate medium with lactate as electron donor at pH 7 buffered with PIPES. Calcium increased both the rate and extent of Na-boltwoodite dissolution by increasing its solubility through the formation of a ternary aqueous calcium-uranyl-carbonate species. The ternary species, however, decreased the rates of microbial reduction of aqueous U(VI). Laser-induced fluorescence spectroscopy (LIFS) and transmission electron microscopy (TEM) revealed that microbial reductionmore » of solid phase U(VI) is a sequentially coupled process of Na-boltwoodite dissolution, U(VI) aqueous speciation, and microbial reduction of dissolved U(VI) to U(IV) that accumulated on bacterial surfaces/periplasm. The overall rates of microbial reduction of solid phase U(VI) can be described by the coupled rates of dissolution and microbial reduction that were both influenced by calcium. The results demonstrated that dissolved U(VI) concentration during microbial reduction was a complex function of solid phase U(VI) dissolution kinetics, aqueous U(VI) speciation, and microbial activity.« less

Singular Instantons and Painlevé VI

NASA Astrophysics Data System (ADS)

Muñiz Manasliski, Richard

2016-06-01

We consider a two parameter family of instantons, which is studied in [Sadun L., Comm. Math. Phys. 163 (1994), 257-291], invariant under the irreducible action of SU_2 on S^4, but which are not globally defined. We will see that these instantons produce solutions to a one parameter family of Painlevé VI equations (P_VI}) and we will give an explicit expression of the map between instantons and solutions to P_{VI}. The solutions are algebraic only for that values of the parameters which correspond to the instantons that can be extended to all of S^4. This work is a generalization of [Muñiz Manasliski R., Contemp. Math., Vol. 434, Amer. Math. Soc., Providence, RI, 2007, 215-222] and [Muñiz Manasliski R., J. Geom. Phys. 59 (2009), 1036-1047, arXiv:1602.07221], where instantons without singularities are studied.

Formic acid interaction with the uranyl(VI) ion: structural and photochemical characterization.

PubMed

Lucks, Christian; Rossberg, André; Tsushima, Satoru; Foerstendorf, Harald; Fahmy, Karim; Bernhard, Gert

2013-10-07

Complex formation between the uranyl(VI) ion and formic acid was studied by infrared absorption (IR) and X-ray absorption (EXAFS) spectroscopy as well as density functional theory (DFT) calculations. In contrast to the acetate ion which forms exclusively a bidentate complex with uranyl(VI), the formate ion binds to uranyl(VI) in a unidentate fashion. The photochemistry of the uranyl(VI)-formic acid system was explored by DFT calculations and photoreduction of uranyl(VI) in the presence of formic acid was found to occur via an intermolecular process, that is, hydrogen abstraction from hydrogenformate by the photo-excited uranyl(VI). There is no photo-induced decarboxylation of uranyl(VI) formate via an intramolecular process, presumably due to lack of a C=C double bond.

U(VI) adsorption on aquifer sediments at the Hanford Site.

PubMed

Um, Wooyong; Serne, R Jeffrey; Brown, Christopher F; Last, George V

2007-08-15

Aquifer sediments collected via split-spoon sampling in two new groundwater wells in the 200-UP-1 operable unit at the Hanford Site were characterized and showed typical Ringold Unit E Formation properties dominated by gravel and sand. High iron-oxide content in Fe oxide/clay coatings caused the highest U(VI) adsorption as quantified by batch K(d) values, indicating iron oxides are the key solid adsorbent in the 200-UP-1 sediments that affect U(VI) fate and mobility. Even though U(VI) adsorption on the gravel-sized fraction of the sediments is considered to be negligible, careful characterization should be conducted to determine U(VI) adsorption on gravel, because of presence of Fe oxides coatings and diffusion-controlled adsorption into the gravel particles' interior surfaces. A linear adsorption isotherm was observed up to 10(-6) M (238 microg/L) of total U(VI) concentration in batch U(VI) adsorption tests with varying total U(VI) concentrations in spiked groundwater. U(VI) adsorption decreased with increasing concentrations of dissolved carbonate, because strong anionic aqueous uranium-carbonate complexes formed at high pH and high alkalinity conditions. Noticeable uranium desorption hysteresis was observed in a flow-through column experiment, suggesting that desorption K(d) values for aged uranium-contaminated sediments at the Hanford Site can be larger than adsorption K(d) values determined in short-term laboratory experiments and slow uranium release from contaminated sediments into the groundwater is expected.

Remediation of Cr(VI)-Contaminated Soil Using the Acidified Hydrazine Hydrate.

PubMed

Ma, Yameng; Li, Fangfang; Jiang, Yuling; Yang, Weihua; Lv, Lv; Xue, Haotian; Wang, Yangyang

2016-09-01

Acidified hydrazine hydrate was used to remediate Cr(VI)-contaminated soil. The content of water-soluble Cr(VI) in contaminated soil was 4977.53 mg/kg. The optimal initial pH of hydrazine hydrate solution, soil to solution ratio and molar ratio of Cr(VI) to hydrazine hydrate for remediation of Cr(VI)-contaminated soil were 5.0, 3:1 and 1:3, respectively. Over 99.50 % of water-soluble Cr(VI) in the contaminated soil was reduced at the optimal condition within 30 min. The remediated soil can keep stable within 4 months. Meanwhile the total phosphorus increased from 0.47 to 4.29 g/kg, indicating that using of acidified hydrazine hydrate is an effective method to remediate Cr(VI)-contaminated soil.

Detection and Persistence of Vi Antigen in Tissues of Actively Immunized Mice1

PubMed Central

Gaines, Sidney; Currie, Julius A.; Tully, Joseph G.

1965-01-01

Gaines, Sidney (Walter Reed Army Institute of Research, Washington, D.C.), Julius A. Currie, and Joseph G. Tully. Detection and persistence of Vi antigen in tissues of actively immunized mice. J. Bacteriol. 89:776–781. 1965.—The presence, distribution, and persistence of Vi antigen in mouse tissue was determined by means of active immunization tests with tissue extracts. Mice were injected intraperitoneally with purified Vi antigen or Vi-containing bacilli. At appropriate intervals, animals were killed, and saline extracts of their tissues were prepared. Mice were immunized with these extracts and challenged 6 days later with 10 ld50 of Salmonella typhosa Ty2. Protection was afforded by tissue extracts from Vi-injected mice, but not by normal tissue extracts. That the immunizing capacity of tissue extracts from Vi-injected mice was attributable to Vi antigen was affirmed by the demonstration that these extracts stimulated the production of Vi antibody in mice, coated erythrocytes for agglutination by Vi antiserum, and inhibited agglutination of Vi-sensitized red blood cells by known Vi antisera. Vi antigen could be detected in the liver and spleen of mice injected with as little as 1 μg. In mice given 150 μg, the antigen was still present in liver tissue 231 days later. PMID:14273660

Simultaneous Cr(VI) bio-reduction and methane production by anaerobic granular sludge.

PubMed

Hu, Qian; Sun, Jiaji; Sun, Dezhi; Tian, Lan; Ji, Yanan; Qiu, Bin

2018-08-01

Wastewater containing toxic hexavalent chromium (Cr(VI)) were treated with well-organized anaerobic granular sludge in this study. Results showed that the anaerobic granular sludge rapidly removed Cr(VI), and 2000 µg·L -1 Cr(VI) was completely eliminated within 6 min, which was much faster than the reported duration of removal by reported artificial materials. Sucrose added as a carbon source acted as an initial electron donor to reduce Cr(VI) to Cr(III). This process was considered as the main mechanism of Cr(VI) removal. Methane production by anaerobic granular sludge was improved by the addition of Cr(VI) at a concentration lower than 500 µg·L -1 . Anaerobic granular sludge had a well-organized structure, which presented good resistance against toxic Cr(VI). Trichoccus accelerated the degradation of organic substances to generate acetates with a low Cr(VI) concentration, thereby enhancing methane production by acetotrophic methanogens. Copyright © 2018 Elsevier Ltd. All rights reserved.

Re-examination of immune response and estimation of anti-Vi IgG protective threshold against typhoid fever-based on the efficacy trial of Vi conjugate in young children.

PubMed

Szu, Shousun C; Klugman, Keith P; Hunt, Steven

2014-04-25

The capsular polysaccharide of Salmonella enterica serovar Typhi, Vi antigen, is an essential virulence factor and a protective antigen. Similar to other polysaccharide vaccines, the protective action of Vi, both to the polysaccharide alone or when presented as a conjugate, is mediated by serum IgG Vi antibodies. The evaluation of Vi capsular polysaccharide based vaccines to prevent typhoid fever would be significantly facilitated by the identification of a "protective level" of serum antibodies to Vi antigen. The protective level of anti-Vi IgG against typhoid fever was derived from the protective efficacy and immune response of a Vi-rEPA conjugate vaccine efficacy trial. The estimation was derived by two methods: correlation of the percent efficacy and the antibody distribution profile in the vaccine group at a given period of observation, and use of the relative ratio of anti-Vi IgG levels between the vaccine and placebo groups greater or equal to the Relative Risk of typhoid fever used in the efficacy determination. Both methods predicted a similar range of a minimum protective level of anti-Vi IgG between 1.4 and 2.0μg/ml (short term threshold). When applying a protective threshold of 10μg/ml at 6 months post immunization, an IgG level in excess of 1.4μg/ml was achieved by 90% of children at 46 months post immunization, consistent with an 89% level of protection over the duration of the study. We thus suggest that the proportion of children with Vi IgG>10μg/ml (long term threshold) 6 months after immunization may reflect the proportion protected over at least a 4 year period. The current assignment of an anti-Vi IgG protective level may be of value when evaluating vaccine performance of future Vi conjugate vaccines. Published by Elsevier Ltd.

Re-examination of immune response and estimation of anti-Vi IgG protective threshold against typhoid fever-based on the efficacy trial of Vi conjugate in young children

PubMed Central

Szu, Shousun C.; Klugman, Keith P.; Hunt, Steven

2014-01-01

Background The capsular polysaccharide of Salmonella enterica serovar Typhi, Vi antigen, is an essential virulence factor and a protective antigen. Similar to other polysaccharide vaccines, the protective action of Vi, both to the polysaccharide alone or when presented as a conjugate, is mediated by serum IgG Vi antibodies. The evaluation of Vi capsular polysaccharide based vaccines to prevent typhoid fever would be significantly facilitated by the identification of a “protective level” of serum antibodies to Vi antigen. Methods The protective level of anti-Vi IgG against typhoid fever was derived from the protective efficacy and immune response of a Vi-rEPA conjugate vaccine efficacy trial. The estimation was derived by two methods: correlation of the percent efficacy and the antibody distribution profile in the vaccine group at a given period of observation, and use of the relative ratio of anti-Vi IgG levels between the vaccine and placebo groups greater or equal to the Relative Risk of typhoid fever used in the efficacy determination. Results Both methods predicted a similar range of a minimum protective level of anti-Vi IgG between 1.4 and 2.0 μg/ml (short term threshold). When applying a protective threshold of 10 μg/ml at 6 months post immunization, an IgG level in excess of 1.4 μg/ml was achieved by 90% of children at 46 months post immunization, consistent with an 89% level of protection over the duration of the study. We thus suggest that the proportion of children with Vi IgG > 10 μg/ml (long term threshold) 6 months after immunization may reflect the proportion protected over at least a 4 year period. Conclusion The current assignment of an anti-Vi IgG protective level may be of value when evaluating vaccine performance of future Vi conjugate vaccines. PMID:24630869

Minimal Clinically Important Differences for American Orthopaedic Foot & Ankle Society Score in Hallux Valgus Surgery.

PubMed

Chan, Hiok Yang; Chen, Jerry Yongqiang; Zainul-Abidin, Suraya; Ying, Hao; Koo, Kevin; Rikhraj, Inderjeet Singh

2017-05-01

The American Orthopaedic Foot & Ankle Society (AOFAS) score is one of the most common and adapted outcome scales in hallux valgus surgery. However, AOFAS is predominantly physician based and not patient based. Although it may be straightforward to derive statistical significance, it may not equate to the true subjective benefit of the patient's experience. There is a paucity of literature defining MCID for AOFAS in hallux valgus surgery although it could have a great impact on the accuracy of analyzing surgical outcomes. Hence, the primary aim of this study was to define the Minimal Clinically Important Difference (MCID) for the AOFAS score in these patients, and the secondary aim was to correlate patients' demographics to the MCID. We conducted a retrospective cross-sectional study. A total of 446 patients were reviewed preoperatively and followed up for 2 years. An anchor question was asked 2 years postoperation: "How would you rate the overall results of your treatment for your foot and ankle condition?" (excellent, very good, good, fair, poor, terrible). The MCID was derived using 4 methods, 3 from an anchor-based approach and 1 from a distribution-based approach. Anchor-based approaches were (1) mean difference in 2-year AOFAS scores of patients who answered "good" versus "fair" based on the anchor question; (2) mean change of AOFAS score preoperatively and at 2-year follow-up in patients who answered good; (3) receiver operating characteristic (ROC) curves method, where the area under the curve (AUC) represented the likelihood that the scoring system would accurately discriminate these 2 groups of patients. The distribution-based approach used to calculate MCID was the effect size method. There were 405 (90.8%) females and 41 (9.2%) males. Mean age was 51.2 (standard deviation [SD] = 13) years, mean preoperative BMI was 24.2 (SD = 4.1). Mean preoperative AOFAS score was 55.6 (SD = 16.8), with significant improvement to 85.7 (SD = 14.4) in 2 years ( P value

Oxidation of Oil Sands Process-Affected Water by Potassium Ferrate(VI).

PubMed

Wang, Chengjin; Klamerth, Nikolaus; Huang, Rongfu; Elnakar, Haitham; Gamal El-Din, Mohamed

2016-04-19

This paper investigates the oxidation of oil sands process-affected water (OSPW) by potassium ferrate(VI). Due to the selectivity of ferrate(VI) oxidation, two-ring and three-ring fluorescing aromatics were preferentially removed at doses <100 mg/L Fe(VI), and one-ring aromatics were removed only at doses ≥100 mg/L Fe(VI). Ferrate(VI) oxidation achieved 64.0% and 78.4% removal of naphthenic acids (NAs) at the dose of 200 mg/L and 400 mg/L Fe(VI) respectively, and NAs with high carbon number and ring number were removed preferentially. (1)H nuclear magnetic resonance ((1)H NMR) spectra indicated that the oxidation of fluorescing aromatics resulted in the opening of some aromatic rings. Electron paramagnetic resonance (EPR) analysis detected signals of organic radical intermediates, indicating that one-electron transfer is one of the probable mechanisms in the oxidation of NAs. The inhibition effect of OSPW on Vibrio fischeri and the toxicity effect on goldfish primary kidney macrophages (PKMs) were both reduced after ferrate(VI) oxidation. The fluorescing aromatics in OSPW were proposed to be an important contributor to this acute toxicity. Degradation of model compounds with ferrate(VI) was also investigated and the results confirmed our findings in OSPW study.

Sorption characteristic of uranium(VI) ion onto K-feldspar.

PubMed

Gao, Xiaoqing; Bi, Mingliang; Shi, Keliang; Chai, Zhifang; Wu, Wangsuo

2017-10-01

The effect of pH, contact time, temperature, ionic strength and initial U(VI) concentration on U(VI) sorption onto K-feldspar was investigated using batch techniques. The sorption kinetics was evaluated and the activation energy was obtained based on the rate constants at different temperature. Graphical correlations of sorption isotherm models have been evaluated and applied for U(VI) uptake by K-feldspar. Various thermodynamic parameters, such as, Gibb's free energy, entropy and enthalpy of the on-going sorption process have been calculated and the possible sorption mechanism of U(VI) was deduced. The results are expected to help better understand the migration of uranium in the host materials of granite. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microstructural analyses of Cr(VI) speciation in chromite ore processing Residue (COPR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

CHRYSOCHOOU, MARIA; FAKRA, SIRINE C .; Marcus, Matthew A.

2010-03-01

The speciation and distribution of Cr(VI) in the solid phase was investigated for two types of chromite ore processing residue (COPR) found at two deposition sites in the United States: gray-black (GB) granular and hard brown (HB) cemented COPR. COPR chemistry and mineralogy were investigated using micro-X-ray absorption spectroscopy and micro-X-ray diffraction, complemented by laboratory analyses. GB COPR contained 30percent of its total Cr(VI) (6000 mg/kg) as large crystals(>20 ?m diameter) of a previously unreported Na-rich analog of calcium aluminum chromate hydrates. These Cr(VI)-rich phases are thought to be vulnerable to reductive and pH treatments. More than 50percent of themore » Cr(VI) was located within nodules, not easily accessible to dissolved reductants, and bound to Fe-rich hydrogarnet, hydrotalcite, and possibly brucite. These phases are stable over a large pH range, thus harder to dissolve. Brownmilleritewasalso likely associated with physical entrapment of Cr(VI) in the interior of nodules. HB COPR contained no Cr(VI)-rich phases; all Cr(VI) was diffuse within the nodules and absent from the cementing matrix, with hydrogarnet and hydrotalcite being the main Cr(VI) binding phases. Treatment ofHBCOPRis challenging in terms of dissolving the acidity-resistant, inaccessible Cr(VI) compounds; the same applies to ~;;50percent of Cr(VI) in GB COPR.« less

Use of 3D Printed Bone Plate in Novel Technique to Surgically Correct Hallux Valgus Deformities

PubMed Central

Smith, Kathryn E.; Dupont, Kenneth M.; Safranski, David L.; Blair, Jeremy; Buratti, Dawn; Zeetser, Vladimir; Callahan, Ryan; Lin, Jason; Gall, Ken

2016-01-01

Three-dimensional (3-D) printing offers many potential advantages in designing and manufacturing plating systems for foot and ankle procedures that involve small, geometrically complex bony anatomy. Here, we describe the design and clinical use of a Ti-6Al-4V ELI bone plate (FastForward™ Bone Tether Plate, MedShape, Inc., Atlanta, GA) manufactured through 3-D printing processes. The plate protects the second metatarsal when tethering suture tape between the first and second metatarsals and is a part of a new procedure that corrects hallux valgus (bunion) deformities without relying on doing an osteotomy or fusion procedure. The surgical technique and two clinical cases describing the use of this procedure with the 3-D printed bone plate are presented within. PMID:28337049

76 FR 62148 - Title VI; Proposed Circular, Environmental Justice; Proposed Circular

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-06

...-0055] Title VI; Proposed Circular, Environmental Justice; Proposed Circular AGENCY: Federal Transit... the September 29, 2011, Federal Register Notices titled ``Title VI; Proposed Circular'' and... September 29, 2011, Federal Register Notices titled ``Title VI; Proposed Circular'' (76 FR 60593) and...

Synthesis of surface Cr (VI)-imprinted magnetic nanoparticles for selective dispersive solid-phase extraction and determination of Cr (VI) in water samples.

PubMed

Qi, Xue; Gao, Shuang; Ding, Guosheng; Tang, An-Na

2017-01-01

A facile, rapid and selective magnetic dispersed solid-phase extraction (dSPE) method for the extraction and enrichment of Cr (VI) prior to flame atomic absorption spectrometry (AAS) was introduced. For highly selective and efficient extraction, magnetic Cr (VI)-imprinted nanoparticles (Fe 3 O 4 @ Cr (VI) IIPs) were prepared by hyphenating surface ion-imprinted with sol-gel techniques. In the preparation process, chromate (Cr(VI)) was used as the template ion; vinylimidazole and 3-aminopropyltriethoxysilane were selected as organic functional monomer and co-monomer respectively. Another reagent, methacryloxypropyltrimethoxysilane was adopted as coupling agent to form the stable covalent bonding between organic and inorganic phases. The effects of various parameters on the extraction efficiency, such as pH of sample solution, the amount of adsorbent, extraction time, the type and concentration of eluent were systematically investigated. Furthermore, the thermodynamic and kinetic properties of the adsorption process were studied to explore the internal adsorption mechanism. Under optimized conditions, the preconcentration factor, limit of detection and linear range of the established dSPE-AAS method for Cr (VI) were found to be 98, 0.29μgL -1 and 4-140μgL -1 , respectively. The developed method was also successfully applied to the analysis of Cr (VI) in different water samples with satisfactory results, proving its reliability and feasibility in real sample analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Ferrate(VI) oxidation of weak-acid dissociable cyanides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ria A. Yngard; Virender K. Sharma; Jan Filip

2008-04-15

Cyanide is commonly found in electroplating, mining, coal gasification, and petroleum refining effluents, which require treatment before being discharged. Cyanide in effluents exists either as free cyanide or as a metal complex. The kinetics of the oxidation of weak-acid dissociable cyanides by an environmentally friendly oxidant, ferrate, were studied as a function of pH (9.1-10.5) and temperature (15-45{sup o}C) using a stopped-flow technique. The weak-acid dissociable cyanides were Cd(CN){sub 4}{sup 2-} and Ni(CN){sub 4}{sup 2-}, and the rate-laws for the oxidation may be -d(Fe(VI))/dt = k (Fe(VI))(M(CN){sub 4}{sup 2-}){sup n} where n = 0.5 and 1 for Cd(CN){sub 4}{sup 2-}more » and Ni(CN){sub 4}{sup 2-}, respectively. The rates decreased with increasing pH and were mostly related to a decrease in concentration of the reactive protonated Fe(VI) species, HFeO{sub 4}{sup -}. The stoichiometries with Fe(VI) were determined to be: 4HFeO{sub 4}{sup -} + M(CN){sub 4}{sup 2-} + 6H{sub 2}O {yields} 4Fe(OH){sub 3} + M{sup 2+} + 4NCO{sup -} + O{sub 2} + 4OH{sup -}. Mechanisms are proposed that agree with the observed reaction rate-laws and stoichiometries of the oxidation of weak-acid dissociable cyanides by Fe(VI). Results indicate that Fe(VI) is effective in removing cyanide in coke oven plant effluent, where organics are also present. 27 refs., 3 figs., 2 tabs.« less

Inhibition of nitrate reduction by chromium (VI) in anaerobic soil microcosms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kourtev, P. S.; Nakatsu, C. H.; Konopka, Allan

2009-10-01

Chromium (VI) is often found as a co-contaminant at sites polluted with organic compounds. We used microcosms amended with glucose or protein, nitrate and increasing concentrations of chromium to study nitrate reduction in Cr(VI) polluted soils. Organic carbon stimulated bacterial activity, but the addition of Cr(VI) caused a lag and then slower rates 5 of CO2 accumulation. Nitrate reduction only occurred after Cr(VI) had been reduced. Bacterial activity was again inhibited when Cr(VI) was added a second time; thus not all Cr-sensitive bacteria were removed in the first phase. Glucose and protein selected for relatively similar bacterial communities, as assayedmore » by PCR-DGGE of the 16S rRNA gene; this selection was modified by the addition of 10 Cr(VI). Cr-resistant bacteria isolated from microcosms were closely related to members of Bacillus, Enterococcus and Propionibacterium sp. Our results indicate that carbon utilization and nitrate reduction in these soils in the presence of Cr(VI) are contingent upon the reduction of the added heavy metal by a limited subset of the bacterial community. The amount of Cr(VI) required to inhibit nitrate reduction was 10-fold less than for aerobic catabolism of the same 15 substrate. We hypothesize that the resistance level of a microbial process is directly related to the diversity of microbes capable of conducting it.« less

Effect of phosphate on U(VI) sorption to montmorillonite: Ternary complexation and precipitation barriers

NASA Astrophysics Data System (ADS)

Troyer, Lyndsay D.; Maillot, Fabien; Wang, Zheming; Wang, Zimeng; Mehta, Vrajesh S.; Giammar, Daniel E.; Catalano, Jeffrey G.

2016-02-01

Phosphate addition is a potential treatment method to lower the solubility of U(VI) in soil and groundwater systems by causing U(VI) phosphate precipitation as well as enhancing adsorption. Previous work has shown that iron oxide surfaces may facilitate the nucleation of U(VI) phosphate minerals and, that under weakly acidic conditions, phosphate also enhances U(VI) adsorption to such phases. Like iron oxides, clays are important reactive phases in the subsurface but little is known about the interaction of U(VI) and phosphate with these minerals. The effect of aqueous phosphate on U(VI) binding to Wyoming montmorillonite (SWy-2) in air-equilibrated systems was investigated. Equilibrium U(VI) uptake to montmorillonite was determined at pH 4, 6 and 8 at discrete initial phosphate concentrations between 0 and 100 μM. The observed behavior of U(VI) indicates a transition from adsorption to precipitation with increasing total uranium and phosphate concentrations at all pH values. At the highest phosphate concentration examined at each pH value, a barrier to U(VI) phosphate nucleation is observed. At lower concentrations, phosphate has no effect on macroscopic U(VI) adsorption. To assess the mechanisms of U(VI)-phosphate interactions on smectite surfaces, U(VI) speciation was investigated under selected conditions using laser-induced fluorescence spectroscopy (LIFS) and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Samples above the precipitation threshold display EXAFS and LIFS spectral signatures consistent with the autunite family of U(VI) phosphate minerals. However, at lower U(VI) concentrations, changes in LIFS spectra upon phosphate addition suggest that U(VI)-phosphate ternary surface complexes form on the montmorillonite surface at pH 4 and 6 despite the lack of a macroscopic effect on adsorption. The speciation of solid-associated U(VI) below the precipitation threshold at pH 8 is dominated by U(VI)-carbonate surface complexes. This work

Effect of Phosphate on U(VI) Sorption to Montmorillonite: Ternary Complexation and Precipitation Barriers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Troyer, Lyndsay D.; Maillot, Fabien; Wang, Zheming

Phosphate addition is a potential treatment method to lower the solubility of U(VI) in soil and groundwater systems by causing U(VI) phosphate precipitation as well as enhancing adsorption. Previous work has shown that iron oxide surfaces may facilitate the nucleation of U(VI) phosphate minerals and, that under weakly acidic conditions, phosphate also enhances U(VI) adsorption to such phases. Like iron oxides, clays are important reactive phases in the subsurface but little is known about the interaction of U(VI) and phosphate with these minerals. The effect of aqueous phosphate on U(VI) binding to Wyoming montmorillonite (SWy-2) in air-equilibrated systems was investigated.more » Equilibrium U(VI) uptake to montmorillonite was determined at pH 4, 6 and 8 at discrete initial phosphate concentrations between 0 and 100 μM. The observed behavior of U(VI) indicates a transition from adsorption to precipitation with increasing total uranium and phosphate concentrations at all pH values. At the highest phosphate concentration examined at each pH value, a barrier to U(VI) phosphate nucleation is observed. At lower concentrations, phosphate has no effect on macroscopic U(VI) adsorption. To assess the mechanisms of U(VI)-phosphate interactions on smectite surfaces, U(VI) speciation was investigated under selected conditions using laser-induced fluorescence spectroscopy (LIFS) and extended X-ray absorption fine-structure (EXAFS) spectroscopy. Samples above the precipitation threshold display EXAFS and LIFS spectral signatures consistent with the autunite family of U(VI) phosphate minerals. However, at lower U(VI) concentrations, changes in LIFS spectra upon phosphate addition suggest that U(VI)-phosphate ternary surface complexes form on the montmorillonite surface at pH 4 and 6 despite the lack of a macroscopic effect on adsorption. The speciation of solid-associated U(VI) below the precipitation threshold at pH 8 is dominated by U(VI)-carbonate surface complexes. This

The MK VI - A second generation attitude control system

NASA Astrophysics Data System (ADS)

Meredith, P. J.

1986-10-01

The MK VI, a new multipurpose attitude control system for the exoatmospheric attitude control of sounding rocket payloads, is described. The system employs reprogrammable microcomputer memory for storage of basic control logic and for specific mission event control data. The paper includes descriptions of MK VI specifications and configuration; sensor characteristics; the electronic, analog, and digital sections; the pneumatic system; ground equipment; the system operation; and software. A review of the MK VI performance for the Comet Halley flight is presented. Block diagrams are included.

Kandinsky's "Composition VI": Heideggerian Poetry in Noah's Ark

ERIC Educational Resources Information Center

Hall, Joshua M.

2012-01-01

The author will begin his investigation of Wassily Kandinsky's painting "Composition VI" with Kandinsky's own commentary on the painting. He will then turn to the analysis of Kandinsky and the "Compositions" in John Sallis's book "Shades." Using this analysis as his point of departure, the author will consider how "Composition VI" resonates with…

Quantifying Cr(VI) Production and Export from Serpentine Soil of the California Coast Range.

PubMed

McClain, Cynthia N; Fendorf, Scott; Webb, Samuel M; Maher, Kate

2017-01-03

Hexavalent chromium (Cr(VI)) is generated in serpentine soils and exported to surface and groundwaters at levels above health-based drinking water standards. Although Cr(VI) concentrations are elevated in serpentine soil pore water, few studies have reported field evidence documenting Cr(VI) production rates and fluxes that govern Cr(VI) transport from soil to water sources. We report Cr speciation (i) in four serpentine soil depth profiles derived from the California Coast Range serpentinite belt and (ii) in local surface waters. Within soils, we detected Cr(VI) in the same horizons where Cr(III)-minerals are colocated with biogenic Mn(III/IV)-oxides, suggesting Cr(VI) generation through oxidation by Mn-oxides. Water-extractable Cr(VI) concentrations increase with depth constituting a 7.8 to 12 kg/km 2 reservoir of Cr(VI) in soil. Here, Cr(VI) is produced at a rate of 0.3 to 4.8 kg Cr(VI)/km 2 /yr and subsequently flushed from soil during water infiltration, exporting 0.01 to 3.9 kg Cr(VI)/km 2 /yr at concentrations ranging from 25 to 172 μg/L. Although soil-derived Cr(VI) is leached from soil at concentrations exceeding 10 μg/L, due to reduction and dilution during transport to streams, Cr(VI) levels measured in local surface waters largely remain below California's drinking water limit.

Removal of chromium (VI) from aqueous solution using walnut hull.

PubMed

Wang, Xue Song; Li, Zhi Zhong; Tao, Sheng Rong

2009-02-01

In this study, removal of chromium (VI) from aqueous solution by walnut hull (a local low-cost adsorbent) was studied. The extent of adsorption was investigated as a function of solution pH, contact time, adsorbent and adsorbate concentration, reaction temperature and supporting electrolyte (sodium chloride). The Cr (VI) removal was pH-dependent, reaching a maximum (97.3%) at pH 1.0. The kinetic experimental data were fitted to the first-order, modified Freundlich, intraparticle diffusion and Elovich models and the corresponding parameters were obtained. A 102.78 kJ/mol Ea (activation energy) for the reaction of chromium (VI) adsorption onto walnut indicated that the rate-limiting step in this case might be a chemically controlled process. Both the Langmuir and Freundlich isotherms were suitable for describing the biosorption of chromium (VI) onto walnut hull. The uptake of chromium (VI) per weight of adsorbent increased with increasing initial chromium (VI) concentration up to 240-480 mg/L, and decreased sharply with increasing adsorbent concentration ranging from 1.0 to 5.0 g/L. An increase in sodium chloride (as supporting electrolyte) concentration was found to induce a negative effect while an increase in temperature was found to give rise to a positive effect on the chromium (VI) adsorption process. Compared to the various other adsorbents reported in the literature, the walnut hull in this study shows very good promise for practical applicability.

Kinetic evaluation of chromium(VI) sorption by water lettuce (Pistia).

PubMed

Chakraborty, Rupa; Karmakar, Sukalpa; Mukherjee, Somnath; Kumar, Sunil

2014-01-01

An investigation was performed to evaluate the uptake capacity of Pistia in living condition for adsorptive removal of chromium(VI) from spiked solution for examining a remedial measure for disposal of chrome-laden wastewater in an urban wetland system. Kinetics results show about 78% removal was achieved for 3 mg/L initial concentration of Cr(VI). Experimental data showed that the root portion absorbed more Cr(VI) (28.54 μg/g) compared to accumulation in leaf (5.73 μg/g). It was also noted that the plant could effectively remove Cr(VI) from the solution with minor damage up to an initial Cr(VI) concentration of 3 mg/L, for which the adsorption isotherm studies were conducted. The maximum uptake capacity of the plant was recorded as 0.05 mg/g of Cr(VI) at the equilibrium level after a contact period of 7 days for an initial concentration of 8 mg /L, although severe physiological damage occurred. The experimental results were plotted in Langmuir and Freundlich isotherm models and both were found to be well fitted (r(2) = 0.979 and r(2) = 0.974 respectively). The high value of n (2.16) reveals a strong bond between the plant root and dissolved Cr(VI), which favours the adsorption process. The order of the reaction was also examined on the basis of uptake capacity and it was found that the second order model fitted best.

75 FR 80818 - Funding Availability for Title VI Grant Applications; Extension

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-23

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Administration on Aging Funding Availability for Title VI... Administration on Aging is extending the date for which the Title VI grants applications for the grant period... on March 31, 2011. Funding Opportunity Title/Program Name: Older Americans Act (OAA), Title VI, Part...

GWM-VI: groundwater management with parallel processing for multiple MODFLOW versions

USGS Publications Warehouse

Banta, Edward R.; Ahlfeld, David P.

2013-01-01

Groundwater Management–Version Independent (GWM–VI) is a new version of the Groundwater Management Process of MODFLOW. The Groundwater Management Process couples groundwater-flow simulation with a capability to optimize stresses on the simulated aquifer based on an objective function and constraints imposed on stresses and aquifer state. GWM–VI extends prior versions of Groundwater Management in two significant ways—(1) it can be used with any version of MODFLOW that meets certain requirements on input and output, and (2) it is structured to allow parallel processing of the repeated runs of the MODFLOW model that are required to solve the optimization problem. GWM–VI uses the same input structure for files that describe the management problem as that used by prior versions of Groundwater Management. GWM–VI requires only minor changes to the input files used by the MODFLOW model. GWM–VI uses the Joint Universal Parameter IdenTification and Evaluation of Reliability Application Programming Interface (JUPITER-API) to implement both version independence and parallel processing. GWM–VI communicates with the MODFLOW model by manipulating certain input files and interpreting results from the MODFLOW listing file and binary output files. Nearly all capabilities of prior versions of Groundwater Management are available in GWM–VI. GWM–VI has been tested with MODFLOW-2005, MODFLOW-NWT (a Newton formulation for MODFLOW-2005), MF2005-FMP2 (the Farm Process for MODFLOW-2005), SEAWAT, and CFP (Conduit Flow Process for MODFLOW-2005). This report provides sample problems that demonstrate a range of applications of GWM–VI and the directory structure and input information required to use the parallel-processing capability.

Integrated Cr(VI) removal using constructed wetlands and composting.

PubMed

Sultana, Mar-Yam; Chowdhury, Abu Khayer Md Muktadirul Bari; Michailides, Michail K; Akratos, Christos S; Tekerlekopoulou, Athanasia G; Vayenas, Dimitrios V

2015-01-08

The present work was conducted to study integrated chromium removal from aqueous solutions in horizontal subsurface (HSF) constructed wetlands. Two pilot-scale HSF constructed wetlands (CWs) units were built and operated. One unit was planted with common reeds (Phragmites australis) and one was kept unplanted. Influent concentrations of Cr(VI) ranged from 0.5 to 10mg/L. The effect of temperature and hydraulic residence time (8-0.5 days) on Cr(VI) removal were studied. Temperature was proved to affect Cr(VI) removal in both units. In the planted unit maximum Cr(VI) removal efficiencies of 100% were recorded at HRT's of 1 day with Cr(VI) concentrations of 5, 2.5 and 1mg/L, while a significantly lower removal rate was recorded in the unplanted unit. Harvested reed biomass from the CWs was co-composted with olive mill wastes. The final product had excellent physicochemical characteristics (C/N: 14.1-14.7, germination index (GI): 145-157%, Cr: 8-10mg/kg dry mass), fulfills EU requirements and can be used as a fertilizer in organic farming. Copyright © 2014 Elsevier B.V. All rights reserved.

Hallux valgus, ankle osteoarthrosis and adult acquired flatfoot deformity: a review of three common foot and ankle pathologies and their treatments

PubMed Central

Crevoisier, Xavier; Assal, Mathieu; Stanekova, Katarina

2016-01-01

The pathogenesis of hallux valgus deformity is multifactorial. Conservative treatment can alleviate pain but is unable to correct the deformity. Surgical treatment must be adapted to the type and severity of the deformity. Success of surgical treatment ranges from 80% to 95%, and complication rates range from 10% to 30%. Ankle osteoarthrosis most commonly occurs as a consequence of trauma. Ankle arthrodesis and total ankle replacement are the most common surgical treatments of end stage ankle osteoarthrosis. Both types of surgery result in similar clinical improvement at midterm; however, gait analysis has demonstrated the superiority of total ankle replacement over arthrodesis. More recently, conservative surgery (extraarticular alignment osteotomies) around the ankle has gained popularity in treating early- to mid-stage ankle osteoarthrosis. Adult acquired flatfoot deformity is a consequence of posterior tibial tendon dysfunction in 80% of cases. Classification is based upon the function of the tibialis posterior tendon, the reducibility of the deformity, and the condition of the ankle joint. Conservative treatment includes orthotics and eccentric muscle training. Functional surgery is indicated for treatment in the early stages. In case of fixed deformity, corrective and stabilising surgery is performed. Cite this article: Crevoisier X, Assal M, Stanekova K. Hallux valgus, ankle osteoarthrosis and adult acquired flatfoot deformity: a review of three common foot and ankle pathologies and their treatments. EFORT Open Rev 2016;1:58–64. DOI: 10.1302/2058-5241.1.000015. PMID:28461929

A survey with Copernicus of interstellar O VI absorption

NASA Technical Reports Server (NTRS)

Jenkins, E. B.; Meloy, D. A.

1974-01-01

The presence of broad, shallow absorptions caused by O VI ions were revealed from UV spectra observations recorded by the Copernicus satellite for thirty-two stars. A table lists survey data on the stars observed for which values of the O VI column densities or their upper limits are extracted. Interstellar rather than circumstellar origin is evident from observation of the lack of correspondence between radical velocities of the stars and those of the O VI profiles. The presence of a low-density high-temperature phase of interstellar gas produced by supernova explosions is suggested.

Experimental Monitoring of Cr(VI) Bio-reduction Using Electrochemical Geophysics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Birsen Canan; Gary R. Olhoeft; William A. Smith

2007-09-01

Many Department of Energy (DOE) sites are contaminated with highly carcinogenic hexavalent chromium (Cr(VI)). In this research, we explore the feasibility of applying complex resistivity to the detection and monitoring of microbially-induced reduction of hexavalent chromium (Cr(VI)) to a less toxic form (Cr(III)). We hope to measure the change in ionic concentration that occurs during this reduction reaction. This form of reduction promises to be an attractive alternative to more expensive remedial treatment methods. The specific goal of this research is to define the minimum and maximum concentration of the chemical and biological compounds in contaminated samples for which themore » Cr(VI) - Cr(III) reduction processes could be detected via complex resistivity. There are three sets of experiments, each comprised of three sample columns. The first experiment compares three concentrations of Cr(VI) at the same bacterial cell concentration. The second experiment establishes background samples with, and without, Cr(VI) and bacterial cells. The third experiment examines the influence of three different bacterial cell counts on the same concentration of Cr(VI). A polarization relaxation mechanism was observed between 10 and 50 Hz. The polarization mechanism, unfortunately, was not unique to bio-chemically active samples. Spectral analysis of complex resistivity data, however, showed that the frequency where the phase minimum occurred was not constant for bio-chemically active samples throughout the experiment. A significant shifts in phase minima occurred between 10 to 20 Hz from the initiation to completion of Cr(VI) reduction. This phenomena was quantified using the Cole-Cole model and the Marquardt-Levenberg nonlinear least square minimization method. The data suggests that the relaxation time and the time constant of this relaxation are the Cole-Cole parameters most sensitive to changes in biologically-induced reduction of Cr(VI).« less

40 CFR Appendix Vi to Part 1039 - Nonroad Compression-ignition Composite Transient Cycle

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Nonroad Compression-ignition Composite Transient Cycle VI Appendix VI to Part 1039 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... ENGINES Pt. 1039, App. VI Appendix VI to Part 1039—Nonroad Compression-ignition Composite Transient Cycle...

Delineation and Diagnostic Criteria of Oral-Facial-Digital Syndrome Type VI

PubMed Central

2012-01-01

Oral-Facial-Digital Syndrome type VI (OFD VI) represents a rare phenotypic subtype of Joubert syndrome and related disorders (JSRD). In the original report polydactyly, oral findings, intellectual disability, and absence of the cerebellar vermis at post-mortem characterized the syndrome. Subsequently, the molar tooth sign (MTS) has been found in patients with OFD VI, prompting the inclusion of OFD VI in JSRD. We studied the clinical, neurodevelopmental, neuroimaging, and genetic findings in a cohort of 16 patients with OFD VI. We derived the following inclusion criteria from the literature: 1) MTS and one oral finding and polydactyly, or 2) MTS and more than one typical oral finding. The OFD VI neuroimaging pattern was found to be more severe than in other JSRD subgroups and includes severe hypoplasia of the cerebellar vermis, hypoplastic and dysplastic cerebellar hemispheres, marked enlargement of the posterior fossa, increased retrocerebellar collection of cerebrospinal fluid, abnormal brainstem, and frequently supratentorial abnormalities that occasionally include characteristic hypothalamic hamartomas. Additionally, two new JSRD neuroimaging findings (ascending superior cerebellar peduncles and fused thalami) have been identified. Tongue hamartomas, additional frenula, upper lip notch, and mesoaxial polydactyly are specific findings in OFD VI, while cleft lip/palate and other types of polydactyly of hands and feet are not specific. Involvement of other organs may include ocular findings, particularly colobomas. The majority of the patients have absent motor development and profound cognitive impairment. In OFD VI, normal cognitive functions are possible, but exceptional. Sequencing of known JSRD genes in most patients failed to detect pathogenetic mutations, therefore the genetic basis of OFD VI remains unknown. Compared with other JSRD subgroups, the neurological findings and impairment of motor development and cognitive functions in OFD VI are significantly

Quantifying Cr(VI) Production and Export from Serpentine Soil of the California Coast Range

DOE PAGES

McClain, Cynthia N.; Fendorf, Scott; Webb, Samuel M.; ...

2016-11-22

Here, hexavalent chromium (Cr(VI)) is generated in serpentine soils and exported to surface and groundwaters at levels above health-based drinking water standards. Although Cr(VI) concentrations are elevated in serpentine soil pore water, few studies have reported field evidence documenting Cr(VI) production rates and fluxes that govern Cr(VI) transport from soil to water sources. We report Cr speciation (i) in four serpentine soil depth profiles derived from the California Coast Range serpentinite belt and (ii) in local surface waters. Within soils, we detected Cr(VI) in the same horizons where Cr(III)-minerals are colocated with biogenic Mn(III/IV)-oxides, suggesting Cr(VI) generation through oxidation bymore » Mn-oxides. Water-extractable Cr(VI) concentrations increase with depth constituting a 7.8 to 12 kg/km 2 reservoir of Cr(VI) in soil. Here, Cr(VI) is produced at a rate of 0.3 to 4.8 kg Cr(VI)/km 2/yr and subsequently flushed from soil during water infiltration, exporting 0.01 to 3.9 kg Cr(VI)/km 2/yr at concentrations ranging from 25 to 172 μg/L. Although soil-derived Cr(VI) is leached from soil at concentrations exceeding 10 μg/L, due to reduction and dilution during transport to streams, Cr(VI) levels measured in local surface waters largely remain below California’s drinking water limit.« less

[Treatment of wastewater containing Cr(VI) by LDH synthesizing in situ].

PubMed

Chen, Tian-hu; Feng, You-liang; Xu, Hui-fang; Peng, Shu-chuan; Huang, Chuan-hui; Tang, Shu-pei

2004-03-01

The objective of this work was to investigate the efficiency and factors impacting of removal Cr(VI) from wastewater by layer double hydroxide synthesizing in situ. Principle of the method may be described as follow: Mg2+ and Al3+ hydrolysis and forms Mg/Al-LDH by adding Mg2+, Al3+ and NaOH into wastewater containing Cr(VI), Cr(VI) anions are selectively intercalated into interlayer of LDH to balance positive structural charge. While Mg2+ and Al3+ co-precipitates and forms LDH, the Cr(VI) in wastewater is removal by settle of LDH synthesizing in situ, which are confirmed by analysis of X-ray diffraction on settle and chemical analysis on aqueous. The results indicate that factors of impacting on efficiency of removal Cr(VI) include in amount of adding Mg2+ and Al3+, Mg/Al ratio, pH and concentration of Cr(VI) in wastewater. The maximal removal efficiency of Cr(VI) can be reached when pH values are between 8.5 and 9, and Mg/Al ratios are between 1:1 and 2:1, meanwhile, Mg and Al added can be taken good use of. This technology has present extraordinary efficiency of wastewater treatment.

Thermodynamic analysis of Cr(VI) extraction using TOPO impregnated membranes.

PubMed

Praveen, Prashant; Loh, Kai-Chee

2016-08-15

Solid/liquid extraction of Cr(VI) was accomplished using trioctylphosphine oxide impregnated polypropylene hollow fiber membranes. Extraction of 100-500mg/L Cr(VI) by the extractant impregnated membranes (EIM) was characterized by high uptake rate and capacity, and equilibrium was attained within 45min of contact. Extraction equilibrium was pH-dependent (at an optimal pH 2), whereas stripping using 0.2M sodium hydroxide yielded the highest recovery of 98% within 60min. The distribution coefficient was independent of initial Cr(VI) concentration, and the linear distribution equilibrium isotherm could be modeled using Freundlich isotherm. The mass transfer kinetics of Cr(VI) was examined using pseudo-second-order and intraparticle diffusion models and a mass transfer mechanism was deduced. The distribution coefficient increased with temperature, which indicated endothermic nature of the reaction. Enthalpy and entropy change during Cr(VI) extraction were positive and varied in the range of 37-49kJ/mol and 114-155J/mol, respectively. The free energy change was negative, confirming the feasibility and spontaneity of the mass transfer process. Results obtained suggest that EIMs are efficient and sustainable for extraction of Cr(VI) from wastewater. Copyright © 2016 Elsevier B.V. All rights reserved.

Kinetics of reduction of plutonium(VI) and neptunium(VI) by sulfide in neutral and alkaline solutions

USGS Publications Warehouse

Nash, K.L.; Cleveland, J.M.; Sullivan, J.C.; Woods, M.

1986-01-01

The rate of reduction of plutonium(VI) and neptunium(VI) by bisulfide ion in neutral and mildly alkaline solutions has been investigated by the stopped-flow technique. The reduction of both of these ions to the pentavalent oxidation state appears to occur in an intramolecular reaction involving an unusual actinide(VI)-hydroxide-bisulfide complex. For plutonium the rate of reduction is 27.4 (??4.1) s-1 at 25??C with ??H* = +33.2 (??1.0) kJ/mol and ??S* = -106 (??4) J/(mol K). The apparent stability constant for the transient complex is 4.66 (??0.94) ?? 103 M-1 at 25??C with associated thermodynamic parameters of ??Hc = +27.7 (??0.4) kJ/mol and ??Sc = +163 (??2) J/(mol K). The corresponding rate and stability constants are determined for the neptunium system at 25??C (k3 = 139 (??30) s-1, Kc. = 1.31 (??0.32) ?? 103 M-1), but equivalent parameters cannot be determined at reduced temperatures. The reaction rate is decreased by bicarbonate ion. At pH > 10.5, a second reaction mechanism, also involving a sulfide complex, is indicated. ?? 1986 American Chemical Society.

A highly selective chemiluminescent probe for the detection of chromium(VI)

NASA Astrophysics Data System (ADS)

Jin, Yan; Sun, Yonghua; Li, Chongying; Yang, Chao

2018-03-01

In present work, rhodamine B hydrazide and rhodamine 6G hydrazide were synthesized and the chemiluminescence performance has been investigated. Based on the chemiluminescence of rhodamine 6G hydrazide-chromium(VI), a selective and sensitive method for the direct detection of chromium(VI) was developed. The chemiluminescence intensity was linearly related to the concentration of chromium(VI) in the range of 2.60 × 10- 8-8.00 × 10- 6 mol/L with a correlation coefficient of r = 0.998 and a detection limit of 1.4 × 10- 8 mol/L (S/N = 3). The results indicated rhodamine 6G hydrazide was an excellent chemiluminescent probe for chromium(VI) without reduction of chromium(VI) to chromium(III). A possible mechanism of CL emission was also suggested.

Long-term diffusion of U(VI) in bentonite: Dependence on density

DOE PAGES

Joseph, Claudia; Mibus, Jens; Trepte, Paul; ...

2016-10-12

As a contribution to the safety assessment of nuclear waste repositories, U(VI) diffusion through the potential buffer material MX-80 bentonite was investigated at three clay dry densities over six years. Synthetic MX-80 model pore water was used as background electrolyte. Speciation calculations showed that Ca 2UO 2(CO 3) 3(aq) was the main U(VI) species. The in- and out-diffusion of U(VI) was investigated separately. U(VI) diffused about 3 mm, 1.5 mm, and 1 mm into the clay plug at ρ = 1.3, 1.6, and 1.9 g/cm 3, respectively. No through-diffusion of the U(VI) tracer was observed. However, leaching of natural uraniummore » contained in the clay occurred and uranium was detected in all receiving reservoirs. As expected, the effective and apparent diffusion coefficients, D e and D a, decreased with increasing dry density. The D a values for the out-diffusion of natural U(VI) were in good agreement with previously determined values. Surprisingly, D a values for the in-diffusion of U(VI) were about two orders of magnitude lower than values obtained in short-term in-diffusion experiments reported in the literature. Some potential reasons for this behavior that were evaluated are changes of the U(VI) speciation within the clay (precipitation, reduction) or changes of the clay porosity and pore connectivity with time. By applying Archie's law and the extended Archie's law, it was estimated that a significantly smaller effective porosity must be present for the long-term in-diffusion of U(VI). Finally, the results suggest that long-term studies of key transport phenomena may reveal additional processes that can directly impact long-term repository safety assessments.« less

HNO3 modified biochars for uranium (VI) removal from aqueous solution.

PubMed

Jin, Jie; Li, Shiwei; Peng, Xianqiang; Liu, Wei; Zhang, Chenlu; Yang, Yan; Han, Lanfang; Du, Ziwen; Sun, Ke; Wang, Xiangke

2018-05-01

The HNO 3 treatment was used to chemically modify the biochars produced from wheat straw (WH) and cow manure for U(VI) removal from aqueous solution. Macroscopic experiments proved that the enrichment of U(VI) on the biochars was regulated by surface complexation and electrostatic interactions. FTIR and XPS analyses confirmed that the highly efficient adsorption of U(VI) was due to the carboxyl groups on the biochar surfaces. The reducing agents of the R-CH 2 OH groups facilitated U(VI) adsorption on the untreated biochars. Owing to the higher contents of surface COO groups and more negative surface charge, the modified biochars showed enhanced U(VI) adsorption ability than the untreated ones. The maximum adsorption capacity of U(VI) by the oxidized WH was calculated to be 355.6 mg/g at pH 4.5 and 298 K, which was an improvement of 40 times relative to the untreated WH and was higher than that of most carbon-based adsorbents. Copyright © 2018 Elsevier Ltd. All rights reserved.

Clinical evaluation of complete solo surgery with the "ViKY®" robotic laparoscope manipulator.

PubMed

Takahashi, Masahiro; Takahashi, Masanori; Nishinari, Naoto; Matsuya, Hideki; Tosha, Tsutomu; Minagawa, Yukihiro; Shimooki, Osamu; Abe, Tadashi

2017-02-01

Advancement in both surgical technique and medical equipment has enabled solo surgery. ViKY ® Endoscope Positioning System (ViKY ® ) is a robotic system that remotely controls an endoscope and provides direct vision control to the surgeon. Here, we report our experience with ViKY ® -assisted solo surgery. We retrospectively examined 25 cases of solo surgery TAPP with ViKY ® . ViKY ® was setup by the surgeon alone, and the setup duration was determined as the time at which the side rail was positioned and that when the endoscope was installed. For assessing the control unit, the number of false movements was counted. We compared the operative results between ViKY ® -assisted solo surgery TAPP and the conventional method with an assistant. The average time to set up ViKY ® was 7.9 min. The average number of commands for ViKY ® during surgery was 98.3, and the average number of errors and no response of control unit was 7.9. The mean duration of surgery was 136 min for the ViKY ® group, including the setup time, and 117 min for the conventional method. No case required an assistant during the operation. There was also no difference between the two groups with regard to postoperative complications and the rate of recurrence. ViKY ® proved reliable in recognizing orders with very few failures, and the operations were performed safely and were comparable to the conventional operations with assistants. Solo surgery with ViKY ® was beneficial in this clinical evaluation.

Treatment of Alkaline Cr(VI)-Contaminated Leachate with an Alkaliphilic Metal-Reducing Bacterium.

PubMed

Watts, Mathew P; Khijniak, Tatiana V; Boothman, Christopher; Lloyd, Jonathan R

2015-08-15

Chromium in its toxic Cr(VI) valence state is a common contaminant particularly associated with alkaline environments. A well-publicized case of this occurred in Glasgow, United Kingdom, where poorly controlled disposal of a cementitious industrial by-product, chromite ore processing residue (COPR), has resulted in extensive contamination by Cr(VI)-contaminated alkaline leachates. In the search for viable bioremediation treatments for Cr(VI), a variety of bacteria that are capable of reduction of the toxic and highly soluble Cr(VI) to the relatively nontoxic and less mobile Cr(III) oxidation state, predominantly under circumneutral pH conditions, have been isolated. Recently, however, alkaliphilic bacteria that have the potential to reduce Cr(VI) under alkaline conditions have been identified. This study focuses on the application of a metal-reducing bacterium to the remediation of alkaline Cr(VI)-contaminated leachates from COPR. This bacterium, belonging to the Halomonas genus, was found to exhibit growth concomitant to Cr(VI) reduction under alkaline conditions (pH 10). Bacterial cells were able to rapidly remove high concentrations of aqueous Cr(VI) (2.5 mM) under anaerobic conditions, up to a starting pH of 11. Cr(VI) reduction rates were controlled by pH, with slower removal observed at pH 11, compared to pH 10, while no removal was observed at pH 12. The reduction of aqueous Cr(VI) resulted in the precipitation of Cr(III) biominerals, which were characterized using transmission electron microscopy and energy-dispersive X-ray analysis (TEM-EDX) and X-ray photoelectron spectroscopy (XPS). The effectiveness of this haloalkaliphilic bacterium for Cr(VI) reduction at high pH suggests potential for its use as an in situ treatment of COPR and other alkaline Cr(VI)-contaminated environments. Copyright © 2015, Watts et al.

A study of the kinetics and isotherms for Cr(VI) adsorption in a binary mixture of Cr(VI)-Ni(II) using hierarchical porous carbon obtained from pig bone.

PubMed

Li, Chengxian; Huang, Zhe; Huang, Bicheng; Liu, Changfeng; Li, Chengming; Huang, Yaqin

2014-01-01

Cr(VI) adsorption in a binary mixture Cr(VI)-Ni(II) using the hierarchical porous carbon prepared from pig bone (HPC) was investigated. The various factors affecting adsorption of Cr(VI) ions from aqueous solutions such as initial concentration, pH, temperature and contact time were analyzed. The results showed excellent efficiency of Cr(VI) adsorption by HPC. The kinetics and isotherms for Cr(VI) adsorption from a binary mixture Cr(VI)-Ni(II) by HPC were studied. The adsorption equilibrium described by the Langmuir isotherm model is better than that described by the Freundlich isotherm model for the binary mixture in this study. The maximum adsorption capacity was reliably found to be as high as 192.68 mg/g in the binary mixture at pH 2. On fitting the experimental data to both pseudo-first- and second-order equations, the regression analysis of the second-order equation gave a better R² value.

Multi-crystalline II-VI based multijunction solar cells and modules

DOEpatents

Hardin, Brian E.; Connor, Stephen T.; Groves, James R.; Peters, Craig H.

2015-06-30

Multi-crystalline group II-VI solar cells and methods for fabrication of same are disclosed herein. A multi-crystalline group II-VI solar cell includes a first photovoltaic sub-cell comprising silicon, a tunnel junction, and a multi-crystalline second photovoltaic sub-cell. A plurality of the multi-crystalline group II-VI solar cells can be interconnected to form low cost, high throughput flat panel, low light concentration, and/or medium light concentration photovoltaic modules or devices.

Uranium(VI) adsorption to ferrihydrite: Application of a surface complexation model

USGS Publications Warehouse

Waite, T.D.; Davis, J.A.; Payne, T.E.; Waychunas, G.A.; Xu, N.

1994-01-01

A study of U(VI) adsorption by ferrihydrite was conducted over a wide range of U(VI) concentrations, pH, and at two partial pressures of carbon dioxide. A two-site (strong- and weak-affinity sites, FesOH and FewOH, respectively) surface complexation model was able to describe the experimental data well over a wide range of conditions, with only one species formed with each site type: an inner-sphere, mononuclear, bidentate complex of the type (FeO2)UO2. The existence of such a surface species was supported by results of uranium EXAFS spectroscopy performed on two samples with U(VI) adsorption density in the upper range observed in this study (10 and 18% occupancy of total surface sites). Adsorption data in the alkaline pH range suggested the existence of a second surface species, modeled as a ternary surface complex with UO2CO30 binding to a bidentate surface site. Previous surface complexation models for U(VI) adsorption have proposed surface species that are identical to the predominant aqueous species, e.g., multinuclear hydrolysis complexes or several U(VI)-carbonate complexes. The results demonstrate that the speciation of adsorbed U(VI) may be constrained by the coordination environment at the surface, giving rise to surface speciation for U(VI) that is significantly less complex than aqueous speciation.

24 CFR 972.115 - Relationship between required conversions and HOPE VI developments.

Code of Federal Regulations, 2010 CFR

2010-04-01

... conversions and HOPE VI developments. 972.115 Section 972.115 Housing and Urban Development Regulations... Relationship between required conversions and HOPE VI developments. HUD actions to approve or deny proposed HOPE VI revitalization plans must be consistent with the requirements of this subpart. Developments...

Ferrate(VI) oxidation of polychlorinated diphenyl sulfides: Kinetics, degradation, and oxidized products.

PubMed

Chen, Jing; Xu, Xinxin; Zeng, Xiaolan; Feng, Mingbao; Qu, Ruijuan; Wang, Zunyao; Nesnas, Nasri; Sharma, Virender K

2018-06-13

This paper presents oxidation of polychlorinated diphenyl sulfides (PCDPSs), dioxin-like compounds, by ferrate(VI) (Fe VI O 4 2- , Fe(VI)). Kinetics of the reactions of Fe(VI) with seventeen PCDPSs, differ in number and positions of chlorine atoms (from 2 to 7), were investigated at pH 8.0. The second-order rate constants (k, M -1 s -1 ) of the reactions varied with the numbers and positions of chlorine atoms and appeared to be related with standard Gibbs free energy of formation (Δ f G 0 ) of PCDPSs. Degradation experiments in the presence of ions and humic acid demonstrated complete removal of PeCDPS by Fe(VI) in minutes. Pathways of the reaction were investigated by identifying oxidized products (OPs) of the reaction between Fe(VI) and 2,2',3',4,5-pentachlorodiphenyl sulfide (PeCDPS) at pH 8.0. Pathways of oxidation involved major pathway of attack on sulfur(II) by Fe(VI) in steps to yield sulfoxide type products, and subsequent breakage of C-S bond with the formation of sulfonic acid-containing trichloro compound. Minor pathways were hydroxylation of benzene ring and substitution of chlorine atom with hydroxyl group. Estimation of toxicity of OPs of the oxidation of PeCDPS by Fe(VI) suggested the decreased toxicity from the parent contaminant. Copyright © 2018. Published by Elsevier Ltd.

Enhanced Cr(VI) removal by polyethylenimine- and phosphorus-codoped hierarchical porous carbons.

PubMed

Chen, Shixia; Wang, Jun; Wu, Zeliang; Deng, Qiang; Tu, Wenfeng; Dai, Guiping; Zeng, Zheling; Deng, Shuguang

2018-08-01

The amino- and phosphorus-codoped (N,P-codoped) porous carbons derived from oil-tea shells were facilely fabricated through a combination of phosphoric acid (H 3 PO 4 ) activation and amino (polyethylenimine, PEI) modification method. The as-synthesized carbon adsorbents were systematically characterized and evaluated for Cr(VI) removal in aqueous solutions. The relationship between adsorbent properties and adsorption behaviors was illustrated. Moreover, the influences of contact time, initial Cr(VI) concentration, pH, coexisting anions and temperature were also investigated. The adsorption behavior of Cr(VI) could be perfectly described by the pseudo-second-order kinetic model and Sips adsorption model. The maximum adsorption capacity of Cr(VI) on the carbon adsorbents synthesized in this work was 355.0 mg/g, and this excellent Cr(VI) capacity could be sustained with other coexisting anions. In addition to high surface area and suitable pore size distribution, the high Cr(VI) removal capacity is induced by rich heteroatoms incorporation and the Cr(VI) removal mechanism was clearly illustrated. Furthermore, the continuous column breakthrough experiment on obtained N,P-codoped carbon was conducted and well fitted by the Thomas model. This work revealed that PEI modification and P-containing groups could significantly enhance Cr(VI) adsorption capacity and make these N,P-codoped biomass-derived carbons potent adsorbents in practical water treatment applications. Copyright © 2018 Elsevier Inc. All rights reserved.

Contribution of extracellular polymeric substances from Shewanella sp. HRCR-1 biofilms to U(VI) immobilization.

PubMed

Cao, Bin; Ahmed, Bulbul; Kennedy, David W; Wang, Zheming; Shi, Liang; Marshall, Matthew J; Fredrickson, Jim K; Isern, Nancy G; Majors, Paul D; Beyenal, Haluk

2011-07-01

The goal of this study was to quantify the contribution of extracellular polymeric substances (EPS) to U(VI) immobilization by Shewanella sp. HRCR-1. Through comparison of U(VI) immobilization using cells with bound EPS (bEPS) and cells with minimal EPS, we show that (i) bEPS from Shewanella sp. HRCR-1 biofilms contribute significantly to U(VI) immobilization, especially at low initial U(VI) concentrations, through both sorption and reduction; (ii) bEPS can be considered a functional extension of the cells for U(VI) immobilization and they likely play more important roles at lower initial U(VI) concentrations; and (iii) the U(VI) reduction efficiency is dependent upon the initial U(VI) concentration and decreases at lower concentrations. To quantify the relative contributions of sorption and reduction to U(VI) immobilization by EPS fractions, we isolated loosely associated EPS (laEPS) and bEPS from Shewanella sp. HRCR-1 biofilms grown in a hollow fiber membrane biofilm reactor and tested their reactivity with U(VI). We found that, when reduced, the isolated cell-free EPS fractions could reduce U(VI). Polysaccharides in the EPS likely contributed to U(VI) sorption and dominated the reactivity of laEPS, while redox active components (e.g., outer membrane c-type cytochromes), especially in bEPS, possibly facilitated U(VI) reduction.

Inactivation of bacteriophage MS2 with potassium ferrate(VI).

PubMed

Hu, Lanhua; Page, Martin A; Sigstam, Therese; Kohn, Tamar; Mariñas, Benito J; Strathmann, Timothy J

2012-11-06

Ferrate [Fe(VI); FeO(4)(2-)] is an emerging oxidizing agent capable of controlling chemical and microbial water contaminants. Here, inactivation of MS2 coliphage by Fe(VI) was examined. The inactivation kinetics observed in individual batch experiments was well described by a Chick-Watson model with first-order dependences on disinfectant and infective phage concentrations. The inactivation rate constant k(i) at a Fe(VI) dose of 1.23 mgFe/L (pH 7.0, 25 °C) was 2.27(±0.05) L/(mgFe × min), corresponding to 99.99% inactivation at a Ct of ~4 (mgFe × min)/L. Measured k(i) values were found to increase with increasing applied Fe(VI) dose (0.56-2.24 mgFe/L), increasing temperature (5-30 °C), and decreasing pH conditions (pH 6-11). The Fe(VI) dose effect suggested that an unidentified Fe byproduct also contributed to inactivation. Temperature dependence was characterized by an activation energy of 39(±6) kJ mol(-1), and k(i) increased >50-fold when pH decreased from 11 to 6. The pH effect was quantitatively described by parallel reactions with HFeO(4)(-) and FeO(4)(2-). Mass spectrometry and qRT-PCR analyses demonstrated that both capsid protein and genome damage increased with the extent of inactivation, suggesting that both may contribute to phage inactivation. Capsid protein damage, localized in the two regions containing oxidant-sensitive cysteine residues, and protein cleavage in one of the two regions may facilitate genome damage by increasing Fe(VI) access to the interior of the virion.

Research progress in the use of ferrate(VI) for the environmental remediation.

PubMed

Jiang, J Q

2007-07-31

The aim of this paper is to review the research progress of using ferrate(VI) in following fields of environmental remediation: (1) water disinfection; (2) degradation of synthetic organic pollutants; (3) treatment of emerging organic pollutants; (4) oxidation of inorganic pollutants; (5) removing humic substance; (6) wastewater treatment and disinfection; and (7) sewage sludge treatment. Whilst the superior performance of potassium ferrate(VI) as an oxidant/disinfectant for the environmental remediation has been demonstrated in various recent researches, challenges have existed to the implementation of ferrate(VI) technology in full-scale water, wastewater and sewage sludge treatment owing to either the instability property of a ferrate(VI) solution or a high preparation cost of a solid ferrate(VI). In addition to this, there are some fundamental issues which have not yet been studied thoroughly which are crucial for the implementation of ferrate(VI)-these lead to the future research work recommended by this paper.

Characterization of U(VI)-carbonato ternary complexes on hematite: EXAFS and electrophoretic mobility measurements

USGS Publications Warehouse

Bargar, John R.; Reitmeyer, Rebecca; Lenhart, John J.; Davis, James A.

2000-01-01

We have measured U(VI) adsorption on hematite using EXAFS spectroscopy and electrophoresis under conditions relevant to surface waters and aquifers (0.01 to 10 μM dissolved uranium concentrations, in equilibrium with air, pH 4.5 to 8.5). Both techniques suggest the existence of anionic U(VI)-carbonato ternary complexes. Fits to EXAFS spectra indicate that U(VI) is simultaneously coordinated to surface FeO6 octahedra and carbonate (or bicarbonate) ligands in bidentate fashions, leading to the conclusion that the ternary complexes have an inner-sphere metal bridging (hematite-U(VI)-carbonato) structure. Greater than or equal to 50% of adsorbed U(VI) was comprised of monomeric hematite-U(VI)-carbonato ternary complexes, even at pH 4.5. Multimeric U(VI) species were observed at pH ≥ 6.5 and aqueous U(VI) concentrations approximately an order of magnitude more dilute than the solubility of crystalline β-UO2(OH)2. Based on structural constraints, these complexes were interpreted as dimeric hematite-U(VI)-carbonato ternary complexes. These results suggest that Fe-oxide-U(VI)-carbonato complexes are likely to be important transport-limiting species in oxic aquifers throughout a wide range of pH values.

Cr(VI) Adsorption on Red Mud Modified by Lanthanum: Performance, Kinetics and Mechanisms

PubMed Central

Cui, You-Wei; Li, Jie; Du, Zhao-Fu; Peng, Yong-Zhen

2016-01-01

Water pollution caused by the highly toxic metal hexavalent chromium (Cr(VI)) creates significant human health and ecological risks. In this study, a novel adsorbent was used to treat Cr(VI)-containing wastewater; the adsorbent was prepared using red mud (RM) generated from the alumina production industry and the rare earth element lanthanum. This study explored adsorption performance, kinetics, and mechanisms. Results showed that the adsorption kinetics of the RM modified by lanthanum (La-RM), followed the pseudo-second-order model, with a rapid adsorption rate. Cr(VI) adsorption was positively associated with the absorbent dose, pH, temperature, and initial Cr(VI) concentration; coexisting anions had little impact. The maximum Cr(VI) adsorption capacity was 17.35 mg/g. Cr(VI) adsorption on La-RM was a mono-layer adsorption pattern, following the Langmuir isotherm model. Thermodynamic parameters showed the adsorption was spontaneous and endothermic. The adsorption of Cr(VI) on La-RM occurred as a result of LaOCl formation on the RM surface, which in turn further reacted with Cr(VI) in the wastewater. This study highlighted a method for converting industrial waste into a valuable material for wastewater treatment. The novel absorbent could be used as a potential adsorbent for treating Cr(VI)-contaminating wastewater, due to its cost-effectiveness and high adsorption capability. PMID:27658113

Cr(VI) remediation by enriched sediment with anthraquinone-2,6-disulfonate as electron shuttles

NASA Astrophysics Data System (ADS)

Chen, Hong; Li, Xiaojuan; Xu, Zhiwei

Hexavalent chromium (Cr(VI)) is a priority pollutant in the USA and many other countries. This study investigated the simultaneous remediation of Cr(VI) in sediment enriched with quinone-reducing microorganisms via a closely coupled, biotic-abiotic pathway. The results showed that Cr(VI) remediation was achieved by sediment adsorption and reduction of quinone-reducing microorganism. Moreover, microorganism reduction of Cr(VI) could be continued when sediment adsorption was saturated after long-term Cr(VI) remediation. The acetate and anthraquinone-2,6-disulfonate (AQDS), which acted as exogenous carbon and electron shuttle, respectively, were two crucial factors. The optimum concentrations of acetate and AQDS were 5 mM and 1 mM when the initial Cr(VI) concentration was 10 mg/L. AQDS was recycled, and it acted in a catalytic-type manner for the bacterial reduction of Cr(VI). Thus, biological humus reduction might provide an extensive pathway for the sequestration and detoxification of Cr(VI) in anaerobic soils, water, and industrial effluents.

Intervening O vi Quasar Absorption Systems at Low Redshift: A Significant Baryon Reservoir.

PubMed

Tripp; Savage; Jenkins

2000-05-01

Far-UV echelle spectroscopy of the radio-quiet QSO H1821+643 (zem=0.297), obtained with the Space Telescope Imaging Spectrograph (STIS) at approximately 7 km s-1 resolution, reveals four definite O vi absorption-line systems and one probable O vi absorber at 0.15vi absorbers are located near galaxies and are highly displaced from the quasar in redshift; these are likely intervening systems unrelated to the background QSO. In the case of the strong O vi system at zabs=0.22497, multiple components are detected in Si iii and O vi as well as H i Lyman series lines, and the differing component velocity centroids and b-values firmly establish that this is a multiphase absorption system. A weak O vi absorber is detected at zabs=0.22637, i.e., offset by approximately 340 km s-1 from the zabs=0.22497 system. Lyalpha absorption is detected at zabs=0.22613, but no Lyalpha absorption is significantly detected at 0.22637. Other weak O vi absorbers at zabs=0.24531 and 0.26659 and the probable O vi system at 0.21326 have widely diverse O vi/H i column density ratios with N(O vi)/N(H i) ranging from vi absorbers with rest equivalent width greater than 30 mÅ in the H1821+643 spectrum is remarkably high, dN&solm0;dz approximately 48, which implies with a high (90%) confidence that it is greater than 17 in the low-redshift intergalactic medium. We conservatively estimate that the cosmological mass density of the O vi systems is Omegab(Ovi&parr0; greater, similar0.0008 h-175. With an assumed metallicity of 1/10 solar and a conservative assumption that the fraction of oxygen in the O vi ionization stage is 0.2, we obtain Omegab(Ovi&parr0; greater, similar0.004 h-175. This is comparable to the combined cosmological mass density of stars and cool gas in galaxies and X-ray-emitting gas in galaxy clusters at low redshift.

Surgical treatment of subacute and chronic valgus instability in multiligament-injured knees with superficial medial collateral ligament reconstruction using Achilles allografts: a quantitative analysis with a minimum 2-year follow-up.

PubMed

Liu, Xin; Feng, Hua; Zhang, Hui; Hong, Lei; Wang, Xue Song; Zhang, Jin; Shen, Jie Wei

2013-05-01

Symptomatic medial collateral ligament (MCL) instability is rare, and it is frequently associated with multiligament injuries. Most clinical investigations have failed to clearly define the specific objective outcome measures assessing the stability of the MCL quantitatively before and after the reconstruction procedure. To quantitatively evaluate the early clinical outcomes of patients with valgus instability of knee joints who had undergone superficial MCL reconstruction using Achilles tendon allografts. Case series; Level of evidence, 4. From August 2005 to December 2010, 19 consecutive patients with MCL injuries were included in this study. The inclusion criteria were (1) a subacute or chronic MCL injury, with a time from initial injury to surgery of longer than 3 weeks, and (2) valgus laxity graded C or D according to the International Knee Documentation Committee (IKDC). All patients underwent superficial MCL reconstruction using Achilles tendon allografts. To evaluate the laxity of the MCL preoperatively and postoperatively, valgus stress radiographs using a Telos device were used. Other assessments included the IKDC subjective functional evaluation and Lysholm score estimation. Sixteen of the 19 patients (12 men and 4 women) were available for final follow-up. The median age of the patients was 37 years (range, 19-53 years); mean body mass index (BMI) was 26.4 (range, 21.7-29.4). The mean time from injury to surgery was 15.9 months (range, 24 days to 84 months), and median follow-up period was 34 months (range, 24-67 months). The mean medial knee laxity (side-to-side difference) was 8.9 ± 3.2 mm (range, 6-15.9 mm) preoperatively and 1.1 ± 0.9 mm (range, -1.1 to 3.2 mm) postoperatively (P < .001). The preoperative mean IKDC subjective knee functional score was 49.8 ± 6.9 (range, 31-57.5), while the postoperative functional score was 84.3 ± 6.0 (range, 71.3-93.1) (P < .001). The mean Lysholm score was 69.3 ± 5.9 (range, 55-78) preoperatively and 88.6 �

Contribution of Extracellular Polymeric Substances from Shewanella sp. HRCR-1 Biofilms to U(VI) Immobilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cao, Bin; Ahmed, B.; Kennedy, David W.

2011-06-05

The goal of this study was to quantify the contribution of extracellular polymeric substances (EPS) in U(VI) immobilization by Shewanella sp. HRCR-1. Through comparison of U(VI) immobilization using cells with bound EPS (bEPS) and cells without EPS, we showed that i) bEPS from Shewanella sp. HRCR-1 biofilms contributed significantly to U(VI) immobilization, especially at low initial U(VI) concentrations, through both sorption and reduction; ii) bEPS could be considered as a functional extension of the cells for U(VI) immobilization and they likely play more important roles at initial U(VI) concentrations; and iii) U(VI) reduction efficiency was found to be dependent uponmore » initial U(VI) concentration and the efficiency decreased at lower concentrations. To quantify relative contribution of sorption and reduction in U(VI) immobilization by EPS fractions, we isolated loosely associated EPS (laEPS) and bEPS from Shewanella sp. HRCR-1 biofilms grown in a hollow fiber membrane biofilm reactor and tested their reactivity with U(V). We found that, when in reduced form, the isolated cell-free EPS fractions could reduce U(VI). Polysaccharides in the EPS likely contributed to U(VI) sorption and dominated reactivity of laEPS while redox active components (e.g., outer membrane c-type cytochromes), especially in bEPS, might facilitate U(VI) reduction.« less

Bicarbonate Impact on U(VI) Bioreduction in a Shallow Alluvial Aquifer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Long, Philip E.; Williams, Kenneth H.; Davis, James A.

Field-scale biostimulation and desorption tracer experiments conducted in a uranium (U) contaminated, shallow alluvial aquifer have provided insight into the coupling of microbiology, biogeochemistry, and hydrogeology that control U mobility in the subsurface. Initial experiments successfully tested the concept that Fe-reducing bacteria such as Geobacter sp. could enzymatically reduce soluble U(VI) to insoluble U(IV) during in situ electron donor amendment (Anderson et al. 2003, Williams et al. 2011). In parallel, in situ desorption tracer tests using bicarbonate amendment demonstrated rate-limited U(VI) desorption (Fox et al. 2012). These results and prior laboratory studies underscored the importance of enzymatic U(VI)-reduction and suggestedmore » the ability to combine desorption and bioreduction of U(VI). Here we report the results of a new field experiment in which bicarbonate-promoted uranium desorption and acetate amendment were combined and compared to an acetate amendment-only experiment in the same experimental plot. Results confirm that bicarbonate amendment to alluvial aquifer desorbs U(VI) and increases the abundance of Ca-uranyl-carbonato complexes. At the same time, that the rate of acetate-promoted enzymatic U(VI) reduction was greater in the presence of added bicarbonate in spite of the increased dominance of Ca-uranyl-carbonato aqueous complexes. A model-simulated peak rate of U(VI) reduction was ~3.8 times higher during acetate-bicarbonate treatment than under acetate-only conditions. Lack of consistent differences in microbial community structure between acetate-bicarbonate and acetate-only treatments suggest that a significantly higher rate of U(VI) reduction the bicarbonate-impacted sediment may be due to a higher intrinsic rate of microbial reduction induced by elevated concentrations of the bicarbonate oxyanion. The findings indicate that bicarbonate amendment may be useful in improving the engineered bioremediation of uranium in aquifers.« less

Bicarbonate impact on U(VI) bioreduction in a shallow alluvial aquifer

NASA Astrophysics Data System (ADS)

Long, Philip E.; Williams, Kenneth H.; Davis, James A.; Fox, Patricia M.; Wilkins, Michael J.; Yabusaki, Steven B.; Fang, Yilin; Waichler, Scott R.; Berman, Elena S. F.; Gupta, Manish; Chandler, Darrell P.; Murray, Chris; Peacock, Aaron D.; Giloteaux, Ludovic; Handley, Kim M.; Lovley, Derek R.; Banfield, Jillian F.

2015-02-01

Field-scale biostimulation and desorption tracer experiments conducted in a uranium (U) contaminated, shallow alluvial aquifer have provided insight into the coupling of microbiology, biogeochemistry, and hydrogeology that control U mobility in the subsurface. Initial experiments successfully tested the concept that Fe-reducing bacteria such as Geobacter sp. could enzymatically reduce soluble U(VI) to insoluble U(IV) during in situ electron donor amendment (Anderson et al., 2003; Williams et al., 2011). In parallel, in situ desorption tracer tests using bicarbonate amendment demonstrated rate-limited U(VI) desorption (Fox et al., 2012). These results and prior laboratory studies underscored the importance of enzymatic U(VI)-reduction and suggested the ability to combine desorption and bioreduction of U(VI). Here we report the results of a new field experiment in which bicarbonate-promoted uranium desorption and acetate amendment were combined and compared to an acetate amendment-only experiment in the same experimental plot. Results confirm that bicarbonate amendment to alluvial aquifer sediments desorbs U(VI) and increases the abundance of Ca-uranyl-carbonato complexes. At the same time, the rate of acetate-promoted enzymatic U(VI) reduction was greater in the presence of added bicarbonate in spite of the increased dominance of Ca-uranyl-carbonato aqueous complexes. A model-simulated peak rate of U(VI) reduction was ∼3.8 times higher during acetate-bicarbonate treatment than under acetate-only conditions. Lack of consistent differences in microbial community structure between acetate-bicarbonate and acetate-only treatments suggest that a significantly higher rate of U(VI) reduction in the bicarbonate-impacted sediment may be due to a higher intrinsic rate of microbial reduction induced by elevated concentrations of the bicarbonate oxyanion. The findings indicate that bicarbonate amendment may be useful in improving the engineered bioremediation of uranium in

[Kinetics modeling and reaction mechanism of ferrate(VI) oxidation of triclosan].

PubMed

Yang, Bin; Ying, Guang-Guo; Zhao, Jian-Liang

2011-09-01

Triclosan (TCS) is a broad-spectrum antibacterial agent widely used in many personal care products. We investigated oxidation of TCS by aqueous ferrate Fe(VI) to determine reaction kinetics, interpreted the reaction mechanism by a linear free-energy relationship, and evaluated the degradation efficiency. Second-order reaction kinetics was used to model Fe (VI) oxidation of TCS, with the apparent second-order rate constant (k(app)) being 531.9 L x (mol x s)(-1) at pH 8.5 and (24 +/- 1) degrees C. The half life (t1/2) is 25.8 s for an Fe( VI) concentration of 10 mg x L(-1). The rate constants of the reaction decrease with increasing pH values. These pH-dependent variations in k(app) could be distributed by considering species-specific reactions between Fe(VI) species and acid-base species of an ionizable TCS. Species-specific second-order reaction rate constants, k, were determined for reaction of HFeO4(-) with each of TCS's acid-base species. The value of k determined for neutral TCS was (4.1 +/- 3.5) x 10(2) L x (mol x s)(-1), while that measured for anionic TCS was (1.8 +/- 0.1) x 10(4) L x (mol x s)(-1). The reaction between HFeO4(-) and the dissociated TCS controls the overall reaction. A linear free-energy relationship illustrated the electrophilic oxidation mechanism. Fe (VI) reacts initially with TCS by electrophilic attack at the latter's phenol moiety. At a n[Fe(VI)]: n(TCS) > 7: 1, complete removal of TCS was achieved. And lower concentration of the humic acid could enhance the k(app) of Fe( VI) with TCS. In conclusion, Fe(VI) oxidation technology appears to be a promising tool for applications of WWTPs effluents and other decontamination processes.

Hereditary motor and sensory neuropathy type VI with optic atrophy.

PubMed

Voo, Irene; Allf, Bryan E; Udar, Nitin; Silva-Garcia, Rosamaria; Vance, Jeffrey; Small, Kent W

2003-10-01

To present the detailed clinical findings of a large family with hereditary motor and sensory neuropathy type VI (HMSN VI), a syndrome featuring optic atrophy. Observational case series. A detailed history was obtained and physical examination was made of the extended family of the proband for evidence of neurologic dysfunction. The OPA1 gene was screened for mutations by direct DNA sequencing. Twelve of 97 family members examined are affected with signs of HMSN VI. Three other members have either optic atrophy or peripheral neuropathy, thus allowing an appreciation of the full clinical spectrum of disease. No mutations were found in the OPA1 gene. This family demonstrates the variable expressivity of this disorder as well as incomplete penetrance. This is the largest known family with HMSN VI. No association was found with changes in the OPA1 gene.

Increases in tibial force imbalance but not changes in tibiofemoral laxities are caused by varus-valgus malalignment of the femoral component in kinematically aligned TKA.

PubMed

Riley, Jeremy; Roth, Joshua D; Howell, Stephen M; Hull, Maury L

2018-01-29

The purposes of this study were to quantify the increase in tibial force imbalance (i.e. magnitude of difference between medial and lateral tibial forces) and changes in laxities caused by 2° and 4° of varus-valgus (V-V) malalignment of the femoral component in kinematically aligned total knee arthroplasty (TKA) and use the results to detemine sensitivities to errors in making the distal femoral resections. Because V-V malalignment would introduce the greatest changes in the alignment of the articular surfaces at 0° flexion, the hypotheses were that the greatest increases in tibial force imbalance would occur at 0° flexion, that primarily V-V laxity would significantly change at this flexion angle, and that the tibial force imbalance would increase and laxities would change in proportion to the degree of V-V malalignment. Kinematically aligned TKA was performed on ten human cadaveric knee specimens using disposable manual instruments without soft tissue release. One 3D-printed reference femoral component, with unmodified geometry, was aligned to restore the native distal and posterior femoral joint lines. Four 3D-printed femoral components, with modified geometry, introduced V-V malalignments of 2° and 4° from the reference component. Medial and lateral tibial forces were measured during passive knee flexion-extension between 0° to 120° using a custom tibial force sensor. Eight laxities were measured from 0° to 120° flexion using a six degree-of-freedom load application system. With the tibial component kinematically aligned, the increase in the tibial force imbalance from that of the reference component at 0° of flexion was sensitive to the degree of V-V malalignment of the femoral component. Sensitivities were 54 N/deg (medial tibial force increasing > lateral tibial force) (p < 0.0024) and 44 N/deg (lateral tibial force increasing > medial tibial force) (p < 0.0077) for varus and valgus malalignments, respectively. Varus-valgus

Determination of Cr(III) solids formed by reduction of Cr(VI) in a contaminated fractured bedrock aquifer: evidence for natural attenuation of Cr(VI)

EPA Science Inventory

Hexavalent chromium Cr(VI) is toxic and can be highly mobile in many aquifer systems. Redox reactions with naturally occurring minerals and organic compounds can reduce Cr(VI) to Cr(III), forming labile Cr(III) oxyhydroxide precipitates, which is a natural attenuation process. In...

Enhanced abiotic reduction of Cr(VI) in a soil slurry system by natural biomaterial addition.

PubMed

Park, Donghee; Ahn, Chi Kyu; Kim, Young Mi; Yun, Yeoung-Sang; Park, Jong Moon

2008-12-30

Among various plant-based natural biomaterials, pine bark was chosen as an efficient biomaterial capable of removing toxic Cr(VI) from aqueous solution. XPS spectra indicated that Cr(VI) was abiotically reduced to Cr(III) in both liquid and solid phases. The Cr(VI)-reducing capacity of pine bark was determined as 545 (+/-1.3)mg-Cr(VI)g(-1) of it, which was 8.7 times higher than that of a common chemical Cr(VI)-reductant, FeSO4 x 7H2O. Because pine bark could completely reduce toxic Cr(VI) to less toxic or nontoxic Cr(III) even at neutral pH, it was used as an organic reductant to remediate Cr(VI)-contaminated soil in this study. Soil slurry system using a bottle roller was applied to ex situ slurry-phase remediation experiments. In the soil slurry system, pine bark completely reduced Cr(VI) to Cr(III) and adsorbed the reduced-Cr(III) on its surface. Abiotic remediation rate of Cr(VI)-contaminated soil increased with the increase of pine bark dosage and with the decreases of Cr(VI) and water contents. In conclusion, pine bark can be used to remediate Cr(VI)-contaminated soil efficiently and environmentally friendly.

Cr(VI) Occurrence and Geochemistry in Water From Public-Supply Wells in California

DOE PAGES

Izbicki, John A.; Wright, Michael T.; Seymour, Whitney A.; ...

2015-08-18

Hexavalent chromium, Cr(VI), in 918 wells sampled throughout California between 2004 and 2012 by the Groundwater Ambient Monitoring and Assessment Program—Priority Basin Project (GAMA—PBP) ranged from less than the study reporting limit (SRL) of 1 microgram per liter (μg/L) to 32 μg/L. Statewide, Cr(VI) was reported in 31 percent of sampled wells and equaled or exceeded the recently established (2014) California Maximum Contaminant Level (MCL) for Cr(VI) of 10 μg/L in 4 percent of sampled wells. Cr(VI) data collected for regulatory purposes overestimate Cr(VI) occurrence. Ninety percent of chromium was present as Cr(VI), which was detected more frequently and atmore » higher concentrations in alkaline (pH > 8), oxic water, and more frequently in agricultural and urban land uses compared to native land uses. Chemical, isotopic (tritium and carbon-14), and noble-gas data show high Cr(VI) in water from wells in alluvial aquifers in the southern California deserts result from long groundwater-residence times and geochemical reactions such as silicate weathering that increase pH, while oxic conditions persist. High Cr(VI) in water from wells in alluvial aquifers along the west-side of the Central Valley results from high-chromium abundance in source rock eroded to form those aquifers, and areal recharge processes (including irrigation return) that mobilize chromium from the unsaturated zone. Cr(VI) co-occurred with oxyanions having similar chemistry, including vanadium, selenium, and uranium. Cr(VI) was positively correlated with nitrate, consistent with increased concentrations in areas of agricultural land use and mobilization of chromium from the unsaturated zone by irrigation return.« less

Cr(VI) occurrence and geochemistry in water from public-supply wells in California

USGS Publications Warehouse

Izbicki, John; Wright, Michael; Seymour, Whitney A.; McCleskey, R. Blaine; Fram, Miranda S.; Belitz, Kenneth; Esser, Bradley K.

2015-01-01

Hexavalent chromium, Cr(VI), in 918 wells sampled throughout California between 2004 and 2012 by the Groundwater Ambient Monitoring and Assessment-Priority Basin Project (GAMA-PBP) ranged from less than the study reporting limit of 1 microgram per liter (μg/L) to 32 μg/L. Statewide, Cr(VI) was reported in 31 percent of wells and equaled or exceeded the recently established (2014) California Maximum Contaminant Level (MCL) for Cr(VI) of 10 μg/L in 4 percent of wells. Cr(VI) data collected for regulatory purposes overestimated Cr(VI) occurrence compared to spatially-distributed GAMA-PBP data. Ninety percent of chromium was present as Cr(VI), which was detected more frequently and at higher concentrations in alkaline (pH ≥ 8), oxic water; and more frequently in agricultural and urban land uses compared to native land uses. Chemical, isotopic (tritium and carbon-14), and noble-gas data show high Cr(VI) in water from wells in alluvial aquifers in the southern California deserts result from long groundwater-residence times and geochemical reactions such as silicate weathering that increase pH, while oxic conditions persist. High Cr(VI) in water from wells in alluvial aquifers along the west-side of the Central Valley results from high-chromium in source rock eroded to form those aquifers, and areal recharge processes (including irrigation return) that can mobilize chromium from the unsaturated zone. Cr(VI) co-occurred with oxyanions having similar chemistry, including vanadium, selenium, and uranium. Cr(VI) was positively correlated with nitrate, consistent with increased concentrations in areas of agricultural land use and mobilization of chromium from the unsaturated zone by irrigation return.

Characterization of the biochemical-pathway of uranium (VI) reduction in facultative anaerobic bacteria.

PubMed

Mtimunye, Phalazane J; Chirwa, Evans M N

2014-10-01

Cultures of U(VI) reducing bacteria sourced from abandoned uranium mine tailing dam were evaluated for their ability to reduce U(VI) to U(IV). The species in the cultures reduced U(VI) in solutions with initial U(VI) concentration up to 400mgL(-)(1) under a near neutral pH of 6.5. The electron flow pathway and fate of reduced species was also analysed in the individual species in order to evaluate the potential for control and optimisation of the reduction potential at the biochemical level. The results showed that U(VI) reduction in live cells was completely blocked by the NADH-dehydrogenase inhibitor, rotenone (C23H22O6), and thioredoxin inhibitor, cadmium chloride (CdCl2), showing that U(VI) reduction involves the electron flow through NADH-dehydrogenase, a primary electron donor to the electron transport respiratory (ETR) system. Mass balance analysis of uranium species aided by visual and electron microscopy suggest that most U(VI) reduction occurred on the cell surface of the isolated species. This finding indicates the possibility of easy uranium recovery for beneficial use through biological remediation. Should the U(VI) be reduced inside the cell, recovery would require complete disruption of the cells and therefore would be difficult. The study contributes new knowledge on the underlying mechanisms in the U(VI) reduction in facultative anaerobes. Copyright © 2014 Elsevier Ltd. All rights reserved.

Mobilization of Cr(VI) from chromite ore processing residue through acid treatment.

PubMed

Tinjum, James M; Benson, Craig H; Edil, Tuncer B

2008-02-25

Batch leaching studies on chromite ore processing residue (COPR) were performed using acids to investigate leaching of hexavalent chromium, Cr(VI), with respect to particle size, reaction time, and type of acid (HNO(3) and H(2)SO(4)). Aqueous Cr(VI) is maximized at approximately 0.04 mol Cr(VI) per kg of dry COPR at pH 7.6-8.1. Cr(VI) mobilized more slowly for larger particles, and the pH increased with time and increased more rapidly for smaller particles, suggesting that rate limitations occur in the solid phase. With H(2)SO(4), the pH stabilized at a higher value (8.8 for H(2)SO(4) vs. 8.0 for HNO(3)) and more rapidly (16 h vs. 30 h), and the differences in pH for different particle sizes were smaller. The acid neutralization capacity (ANC) of COPR is very large (8 mol HNO(3) per kg of dry COPR for a stable eluate pH of 7.5). Changes to the elemental and mineralogical composition and distribution in COPR particles after mixing with acid indicate that Cr(VI)-bearing solids dissolved. However, concentrations of Cr(VI) >2800 mg kg(-1) (>50% of the pre-treatment concentration) were still found after mixing with acid, regardless of the particle size, reaction time, or type of acid used. The residual Cr(VI) appears to be partially associated with poorly-ordered Fe and Al oxyhydroxides that precipitated in the interstitial areas of COPR particles. Remediation strategies that use HNO(3) or H(2)SO(4) to neutralize COPR or to maximize Cr(VI) in solution are likely to require extensive amounts of acid, may not mobilize all of the Cr(VI), and may require extended contact time, even under well-mixed conditions.

Bioreduction of U(VI) and stability of immobilized uranium under suboxic conditions.

PubMed

Hu, Nan; Ding, De-xin; Li, Shi-mi; Tan, Xiang; Li, Guang-yue; Wang, Yong-dong; Xu, Fei

2016-04-01

In order to study the bioreduction of U(VI) and stability of immobilized uranium under suboxic conditions, microcosm were amended with ethanol, lactate and glucose, and incubated under suboxic conditions. During the incubation, total dissolved U in amended microcosms decreased from 0.95 mg/L to 0.03 mg/L. Pyrosequencing results showed that, the proportion of anaerobic microorganisms capable of reducing U(VI) under suboxic conditions was small compared with that under anoxic conditions; the proportion of aerobic and facultative anaerobic microorganisms capable of consuming the dissolved oxygen was large; and some of the facultative anaerobic microorganisms could reduce U(VI). These results indicated that different microbial communities were responsible for the bioreduction of U(VI) under suboxic and anoxic conditions. After the electron donors were exhausted, total dissolved U in the amended microcosms remained unchanged, while the U(VI)/U(IV) ratio in the solid phase of sediments increased obviously. This implied that the performance of bioreduction of the U(VI) can be maintained under suboxic condition. Copyright © 2016 Elsevier Ltd. All rights reserved.

Oxidation of diclofenac by potassium ferrate (VI): reaction kinetics and toxicity evaluation.

PubMed

Wang, Yingling; Liu, Haijin; Liu, Guoguang; Xie, Youhai; Gao, Shuyan

2015-02-15

The reaction kinetics and toxicity of diclofenac (DCF) oxidation by ferrate (VI) under simulated water disinfection conditions were investigated. Experimental results indicated that the reaction between DCF and Fe(VI) followed first-order kinetics with respect to each reactant. Furthermore, the effects of pH and temperature on DCF oxidation by Fe(VI) were elucidated using a systematic examination. The apparent second-order rate constants (kapp) increased significantly from 2.54 to 11.6M(-1)s(-1), as the pH of the solution decreased from 11.0 to 7.0, and the acid-base equilibriums of Fe(VI) and DCF were proposed to explain the pH dependence of kapp. The acute toxicity of DCF solution during Fe(VI) oxidation was evaluated using a Microtox bioassay. Overall, the DCF degradation process resulted in a rapid increase of the inhibition rate of luminescent bacteria. These toxicity tests suggest that the formation of enhanced toxic intermediates during the Fe(VI) disinfection process may pose potential health risk to consumers. Copyright © 2014 Elsevier B.V. All rights reserved.

[Mechanism and promotion effect of K+ on yield of Fe(VI)].

PubMed

Zhang, Yan-Ping; Xu, Guo-Ren; Li, Gui-Bai

2008-03-01

The mechanism and promotion effects of K+ on the yield of Fe(VI) were studied during the reaction of forming ferrate. The experiment results showed that K+ is far better than Na+ for the preparation of Fe(VI) at temperatures higher than 50 degrees C. The optimal temperature for the preparation of Fe(VI) with K+ is 65 degrees C. During the reaction, the yield of ferrate increases with the concentration of K+, and the promotion effect of K+ is obviously with ferric nitrate dosage increase. The Fe(VI) concentration prepared with 4.4 mol/L KOH is 0.05 mol/L at 85 g/L ferric nitrate; and which achieves 0.15 mol/L when added 2 mol/L K+. The promotion effect of K+ on the yield of ferrate is remarkable when ferric nitrate dosage is higher than 75 g/L, reaction temperature is below 55 degrees C and ClO(-) concentration is lower than 1.16 mol/L. The K+ can substitute for partly alkalinity and reduce the concentration of OH(-) in the reaction solution. During the reaction, the K+ can enwrap around FeO4(2-) that can reduce the contact between Fe(3+) and FeO4(2-), and decrease the catalysis effect of Fe(3+) on FeO4(2-). At the same time, K+ can react with FeO4(2-) to form solid K4FeO4, whichwill lower the Fe(VI) concentration, decrease the decomposition rate of Fe(VI), enhance the stability and improve the yield of Fe(VI).

Clinical and serological responses following primary and booster immunization with Salmonella typhi Vi capsular polysaccharide vaccines.

PubMed

Keitel, W A; Bond, N L; Zahradnik, J M; Cramton, T A; Robbins, J B

1994-01-01

Clinical and serum antibody responses following intramuscular injection of two formulations of Salmonella typhi Vi capsular polysaccharide (Vi) were assessed in a double-blind evaluation. Healthy adults were randomly assigned to receive a 25 micrograms dose of liquid (Vi-Liq; n = 182) or freeze-dried Vi vaccine (Vi-Lyoph; n = 55), or placebo (n = 86). Erythema and/or induration > or = 1 cm in diameter at the injection site developed in 13/182 (7%) of Vi-Liq and 3/55 (5%) of Vi-Lyoph recipients (not significant, n.s.). Fever (oral temperature > or = 100 degrees F (37.8 degrees C)) occurred in < 2% of vaccinees. The frequencies of rises of fourfold or greater and of maximal Vi antibody levels were similar in the two vaccine groups. Fourfold or greater rises in serum Vi antibody levels (RIA) developed in 53% of Vi-Lyoph and 60% of Vi-Liq recipients by 1 week (n.s.), and 98 and 93%, respectively, by 1 month (n.s.). The frequencies of adverse reactions and mean Vi antibody levels following booster immunization with Vi-Liq 27 to 34 months after primary immunization (n = 55) were similar to those observed following primary immunization, although subjects given a booster dose were more likely to develop local reactions > or = 1 cm in diameter than those given a first dose (10/55 versus 13/182, p = 0.013 by the chi 2 test). Primary and booster immunizations with the Vi vaccines are well tolerated in healthy adults; mean Vi antibody levels remain significantly elevated for up to 34 months after primary immunization.

Methods for Estimating Adsorbed Uranium(VI) and Distribution Coefficients of Contaminated Sediments

USGS Publications Warehouse

Kohler, M.; Curtis, G.P.; Meece, D.E.; Davis, J.A.

2004-01-01

Assessing the quantity of U(VI) that participates in sorption/desorption processes in a contaminated aquifer is an important task when investigating U migration behavior. U-contaminated aquifer sediments were obtained from 16 different locations at a former U mill tailings site at Naturita, CO (U.S.A.) and were extracted with an artificial groundwater, a high pH sodium bicarbonate solution, hydroxylamine hydrochloride solution, and concentrated nitric acid. With an isotopic exchange method, both a KD value for the specific experimental conditions as well as the total exchangeable mass of U(VI) was determined. Except for one sample, KD values determined by isotopic exchange with U-contaminated sediments that were in equilibrium with atmospheric CO2 agreed within a factor of 2 with KD values predicted from a nonelectrostatic surface complexation model (NEM) developed from U(VI) adsorption experiments with uncontaminated sediments. The labile fraction of U(VI) and U extracted by the bicarbonate solution were highly correlated (r2 = 0.997), with a slope of 0.96 ?? 0.01. The proximity of the slope to one suggests that both methods likely access the same reservoir of U(VI) associated with the sediments. The results indicate that the bicarbonate extraction method is useful for estimating the mass of labile U(VI) in sediments that do not contain U(IV). In-situ KD values calculated from the measured labile U(VI) and the dissolved U(VI) in the Naturita alluvial aquifer agreed within a factor of 3 with in-situ K D values predicted with the NEM and groundwater chemistry at each well.

Natural and man-made hexavalent chromium, Cr(VI), in groundwater near a mapped plume, Hinkley, California—study progress as of May 2017, and a summative-scale approach to estimate background Cr(VI) concentrations

USGS Publications Warehouse

Izbicki, John A.; Groover, Krishangi D.

2018-03-22

This report describes (1) work done between January 2015 and May 2017 as part of the U.S. Geological Survey (USGS) hexavalent chromium, Cr(VI), background study and (2) the summative-scale approach to be used to estimate the extent of anthropogenic (man-made) Cr(VI) and background Cr(VI) concentrations near the Pacific Gas and Electric Company (PG&E) natural gas compressor station in Hinkley, California. Most of the field work for the study was completed by May 2017. The summative-scale approach and calculation of Cr(VI) background were not well-defined at the time the USGS proposal for the background Cr(VI) study was prepared but have since been refined as a result of data collected as part of this study. The proposed summative scale consists of multiple items, formulated as questions to be answered at each sampled well. Questions that compose the summative scale were developed to address geologic, hydrologic, and geochemical constraints on Cr(VI) within the study area. Each question requires a binary (yes or no) answer. A score of 1 will be assigned for an answer that represents data consistent with anthropogenic Cr(VI); a score of –1 will be assigned for an answer that represents data inconsistent with anthropogenic Cr(VI). The areal extent of anthropogenic Cr(VI) estimated from the summative-scale analyses will be compared with the areal extent of anthropogenic Cr(VI) estimated on the basis of numerical groundwater flow model results, along with particle-tracking analyses. On the basis of these combined results, background Cr(VI) values will be estimated for “Mojave-type” deposits, and other deposits, in different parts of the study area outside the summative-scale mapped extent of anthropogenic Cr(VI).

Mechanism of uranium (VI) removal by two anaerobic bacterial communities.

PubMed

Martins, Mónica; Faleiro, Maria Leonor; da Costa, Ana M Rosa; Chaves, Sandra; Tenreiro, Rogério; Matos, António Pedro; Costa, Maria Clara

2010-12-15

The mechanism of uranium (VI) removal by two anaerobic bacterial consortia, recovered from an uncontaminated site (consortium A) and other from an uranium mine (consortium U), was investigated. The highest efficiency of U (VI) removal by both consortia (97%) occurred at room temperature and at pH 7.2. Furthermore, it was found that U (VI) removal by consortium A occurred by enzymatic reduction and bioaccumulation, while the enzymatic process was the only mechanism involved in metal removal by consortium U. FTIR analysis suggested that after U (VI) reduction, U (IV) could be bound to carboxyl, phosphate and amide groups of bacterial cells. Phylogenetic analysis of 16S rRNA showed that community A was mainly composed by bacteria closely related to Sporotalea genus and Rhodocyclaceae family, while community U was mainly composed by bacteria related to Clostridium genus and Rhodocyclaceae family. Copyright © 2010 Elsevier B.V. All rights reserved.

Leg stiffness, valgus knee motion, and Q-angle are associated with hypertrophic soft patella tendon and idiopathic knee pain in adolescent basketball players.

PubMed

Satkunskiene, Danguole; Mickevicius, Mantas; Snieckus, Audrius; Kamandulis, Sigitas

2017-01-01

Knee pain without knee degenerative symptoms is a common phenomenon among young basketball players. The aim of this study was to identify factors predisposing young basketball players to suffer from knee pain. The study involved 20 male adolescent (14-15 years) basketball players who were divided into two equal groups based on knee pain symptoms. Legs torque was tested on an isokinetic dynamometer. The length, elongation and the cross-sectional area (CSA) of the patellar tendon were measured with ultrasonography. Quadriceps angle (Q-angle), knee valgus motion, and joint angular displacement in the sagittal plane were analyzed using video recording during countermovement jump. Ground reaction force was measured using a force platform. Knee pain (KP) participants had a significantly lower Q-angle (P=0.045) and lower maximum varus knee angle (P=0.035), and a greater knee inside displacement (P=0.039) during squat phase. In the KP group, the CSA at the top of the tendon was significantly greater than in the middle (P=0.006) and at the bottom (P=0.039). Absolute tendon stiffness (P=0.013) and Young's modulus (P=0.034) were significantly lower in the KP group compared with controls. Leg stiffness during landing was significantly greater in the control group (P=0.015). Leg stiffness, valgus knee motion, and Q-angle are associated with hypertrophic soft patella tendon and idiopathic knee pain in adolescent basketball players.

Biased Brownian motion mechanism for processivity and directionality of single-headed myosin-VI.

PubMed

Iwaki, Mitsuhiro; Iwane, Atsuko Hikikoshi; Ikebe, Mitsuo; Yanagida, Toshio

2008-01-01

Conventional form to function as a vesicle transporter is not a 'single molecule' but a coordinated 'two molecules'. The coordinated two molecules make it complicated to reveal its mechanism. To overcome the difficulty, we adopted a single-headed myosin-VI as a model protein. Myosin-VI is an intracellular vesicle and organelle transporter that moves along actin filaments in a direction opposite to most other known myosin classes. The myosin-VI was expected to form a dimer to move processively along actin filaments with a hand-over-hand mechanism like other myosin organelle transporters. However, wild-type myosin-VI was demonstrated to be monomer and single-headed, casting doubt on its processivity. Using single molecule techniques, we show that green fluorescent protein (GFP)-fused single-headed myosin-VI does not move processively. However, when coupled to a 200 nm polystyrene bead (comparable to an intracellular vesicle in size) at a ratio of one head per bead, single-headed myosin-VI moves processively with large (40 nm) steps. Furthermore, we found that a single-headed myosin-VI-bead complex moved more processively in a high-viscous solution (40-fold higher than water) similar to cellular environment. Because diffusion of the bead is 60-fold slower than myosin-VI heads alone in water, we propose a model in which the bead acts as a diffusional anchor for the myosin-VI, enhancing the head's rebinding following detachment and supporting processive movement of the bead-monomer complex. This investigation will help us understand how molecular motors utilize Brownian motion in cells.

Oxidation of Sulfonamides in Aqueous Solution by UV-TiO2-Fe(VI).

PubMed

Ma, Yan; Zhang, Kejia; Li, Cong; Zhang, Tuqiao; Gao, Naiyun

2015-01-01

The photocatalytic degradation of sulfonamides in aqueous TiO2 suspension under UV irradiation has been investigated using potassium ferrate as electron acceptors. The results showed that the stability of Fe(VI) is dependent on pH significantly, and the stability reduces obviously in the presence of UV-TiO2. The experiments indicated that Fe(VI) could effectively scavenge the conduction band electrons from the surface of TiO2. The photocatalytic oxidation of sulfonamides with Fe(VI) was found to be much faster than that without Fe(VI). The SD, SM, and SMX concentration was greatly reduced by 89.2%, 83.4%, and 82.0%, respectively, after 10 min with UV-TiO2-Fe(VI), comparing to 65.2%, 66.0%, and 71.9%, respectively, with Fe(VI) only in the dark and 71.3%, 72.7%, and 76.0%, respectively, with UV-TiO2. The pH value of solution significantly influenced the sulfonamides degradation in UV-TiO2-Fe(VI) system. The degradation amount of sulfonamides after 10 min was a maximum at pH 7. The intermediate products of sulfonamides oxidation by UV-TiO2-Fe(VI) were analysed by LC-HESI-MS-MS and the results suggested that a majority of sulfonamides turned into large-molecule products without complete mineralization.

Oxidation of Sulfonamides in Aqueous Solution by UV-TiO2-Fe(VI)

PubMed Central

Ma, Yan; Zhang, Kejia; Li, Cong; Zhang, Tuqiao; Gao, Naiyun

2015-01-01

The photocatalytic degradation of sulfonamides in aqueous TiO2 suspension under UV irradiation has been investigated using potassium ferrate as electron acceptors. The results showed that the stability of Fe(VI) is dependent on pH significantly, and the stability reduces obviously in the presence of UV-TiO2. The experiments indicated that Fe(VI) could effectively scavenge the conduction band electrons from the surface of TiO2. The photocatalytic oxidation of sulfonamides with Fe(VI) was found to be much faster than that without Fe(VI). The SD, SM, and SMX concentration was greatly reduced by 89.2%, 83.4%, and 82.0%, respectively, after 10 min with UV-TiO2-Fe(VI), comparing to 65.2%, 66.0%, and 71.9%, respectively, with Fe(VI) only in the dark and 71.3%, 72.7%, and 76.0%, respectively, with UV-TiO2. The pH value of solution significantly influenced the sulfonamides degradation in UV-TiO2-Fe(VI) system. The degradation amount of sulfonamides after 10 min was a maximum at pH 7. The intermediate products of sulfonamides oxidation by UV-TiO2-Fe(VI) were analysed by LC-HESI-MS-MS and the results suggested that a majority of sulfonamides turned into large-molecule products without complete mineralization. PMID:26347888

Biological Cr(VI) removal using bio-filters and constructed wetlands.

PubMed

Michailides, Michail K; Sultana, Mar-Yam; Tekerlekopoulou, Athanasia G; Akratos, Christos S; Vayenas, Dimitrios V

2013-01-01

The bioreduction of hexavalent chromium from aqueous solution was carried out using suspended growth and packed-bed reactors under a draw-fill operating mode, and horizontal subsurface constructed wetlands. Reactors were inoculated with industrial sludge from the Hellenic Aerospace Industry using sugar as substrate. In the suspended growth reactors, the maximum Cr(VI) reduction rate (about 2 mg/L h) was achieved for an initial concentration of 12.85 mg/L, while in the attached growth reactors, a similar reduction rate was achieved even with high initial concentrations (109 mg/L), thus confirming the advantage of these systems. Two horizontal subsurface constructed wetlands (CWs) pilot-scale units were also built and operated. The units contained fine gravel. One unit was planted with common reeds and one was kept unplanted. The mean influent concentrations of Cr(VI) were 5.61 and 5.47 mg/L for the planted and unplanted units, respectively. The performance of the planted CW units was very effective as mean Cr(VI) removal efficiency was 85% and efficiency maximum reached 100%. On the contrary, the unplanted CW achieved very low Cr(VI) removal with a mean value of 26%. Both attached growth reactors and CWs proved efficient and viable means for Cr(VI) reduction.

Phase VI Glove Durability Testing

NASA Technical Reports Server (NTRS)

Mitchell, Kathryn

2011-01-01

The current state-of-the-art space suit gloves, the Phase VI gloves, have an operational life of 25 -- 8 hour Extravehicular Activities (EVAs) in a dust free, manufactured microgravity EVA environment. Future planetary outpost missions create the need for space suit gloves which can endure up to 90 -- 8 hour traditional EVAs or 576 -- 45 minute suit port-based EVAs in a dirty, uncontrolled planetary environment. Prior to developing improved space suit gloves for use in planetary environments, it is necessary to understand how the current state-of-the-art performs in these environments. The Phase VI glove operational life has traditionally been certified through cycle testing consisting of International Space Station (ISS)-based EVA tasks in a clean environment, and glove durability while performing planetary EVA tasks in a dirty environment has not previously been characterized. Testing was performed in the spring of 2010 by the NASA Johnson Space Center (JSC) Crew and Thermal Systems Division (CTSD) to characterize the durability of the Phase VI Glove and identify areas of the glove design which need improvement to meet the requirements of future NASA missions. Lunar simulant was used in this test to help replicate the dirty lunar environment, and generic planetary surface EVA tasks were performed during testing. A total of 50 manned, pressurized test sessions were completed in the Extravehicular Mobility Unit (EMU) using one pair of Phase VI gloves as the test article. The 50 test sessions were designed to mimic the total amount of pressurized cycling the gloves would experience over a 6 month planetary outpost mission. The gloves were inspected periodically throughout testing, to assess their condition at various stages in the test and to monitor the gloves for failures. Additionally, motion capture and force data were collected during 18 of the 50 test sessions to assess the accuracy of the cycle model predictions used in testing and to feed into the

Chlorine decay and trihalomethane formation following ferrate(VI) preoxidation and chlorination of drinking water.

PubMed

Li, Cong; Luo, Feng; Dong, Feilong; Zhao, Jingguo; Zhang, Tuqiao; He, Guilin; Cizmas, Leslie; Sharma, Virender K

2017-11-01

This paper presents the effect of preoxidation with ferrate(VI) (Fe VI O 4 2- , Fe(VI)) prior to chlorination on chlorine decay and formation of disinfection by-products in filtered raw water from a full-scale drinking water treatment plant. The rate of chlorine decay became significantly faster as the concentration of ferrate(VI) increased. Chlorine degradation followed two first-order decay reactions with rate constants k 1 and k 2 for fast and slow decay, respectively. Kinetic modeling established the relationships between k 1 and k 2 and varying dosages of chlorine and ferrate(VI). When ferrate(VI) was used as a pre-oxidant, the levels of trihalomethanes (trichloromethane (TCM), dichlorobromomethane (DCBM), dibromochloromethane (DBCM), and tribromomethane (TBM)) in water samples decreased as the ferrate(VI) concentration increased. The concentrations of these trihalomethanes followed the order TCM > DCBM ≈ DBCM > TBM. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polyaniline (PANI) modified bentonite by plasma technique for U(VI) removal from aqueous solution

NASA Astrophysics Data System (ADS)

Liu, Xinghao; Cheng, Cheng; Xiao, Chengjian; Shao, Dadong; Xu, Zimu; Wang, Jiaquan; Hu, Shuheng; Li, Xiaolong; Wang, Weijuan

2017-07-01

Polyaniline (PANI) modified bentonite (PANI/bentonie) was synthesized by plasma induced polymerization of aniline on bentonite surface, and applied to uptake of uranium(VI) ions from aqueous solution. The as-synthesized PANI/bentonie was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). Batch adsorption technique was utilized to investigate the adsorption of U(VI) on bentonite and PANI/bentonite. The adsorption of U(VI) (10 mg/L) on PANI/bentonite surface is fairly depend on solution pH, ionic strength, and temperature in solution. The modified PANI on PANI/bentonite surface significantly enhances its adsorption capability for U(VI). The presence of humic acid (HA) can sound enhance U(VI) adsorption on PANI/bentonite at pH < 6.5 because of the strong complexation, and inhibits U(VI) adsorption at pH > 6.5. According to the thermodynamic parameters, the adsorption of U(VI) on PANI/bentonite surface is a spontaneous and endothermic process. The results highlight the application of PANI/bentonite composites as candidate material for the uptake of trace U(VI) from aqueous solution.

23 CFR 200.11 - Procedures for processing Title VI reviews.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Procedures for processing Title VI reviews. 200.11 Section 200.11 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.11 Procedures for processing Title...

23 CFR 200.11 - Procedures for processing Title VI reviews.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Procedures for processing Title VI reviews. 200.11 Section 200.11 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.11 Procedures for processing Title...

23 CFR 200.11 - Procedures for processing Title VI reviews.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Procedures for processing Title VI reviews. 200.11 Section 200.11 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.11 Procedures for processing Title...

23 CFR 200.11 - Procedures for processing Title VI reviews.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Procedures for processing Title VI reviews. 200.11 Section 200.11 Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION CIVIL RIGHTS TITLE VI PROGRAM AND RELATED STATUTES-IMPLEMENTATION AND REVIEW PROCEDURES § 200.11 Procedures for processing Title...

Thermodynamic Insight into the Solvation and Complexation Behavior of U(VI) in Ionic Liquid: Binding of CMPO with U(VI) Studied by Optical Spectroscopy and Calorimetry.

PubMed

Wu, Qi; Sun, Taoxiang; Meng, Xianghai; Chen, Jing; Xu, Chao

2017-03-06

The complexation of U(VI) with octylphenyl-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO, denoted as L) in ionic liquid (IL) C 4 mimNTf 2 was investigated by UV-vis absorption spectrophotometry and isothermal titration calorimetry. Spectro-photometric titration suggests that three successive complexes, UO 2 L j 2+ (j = 1-3), formed both in "dry" (water content < 250 ppm) and "wet" (water content ≈ 12 500 ppm) ionic liquid. However, the thermodynamic parameters are distinctly different in the two ILs. In dry IL, the complexation strength between CMPO and U(VI) is much stronger, with stability constants of the respective complexes more than 1 order of magnitude higher than that in wet IL. Energetically, the complexation of U(VI) with CMPO in dry IL is mainly driven by negative enthalpies. In contrast, the complexation in wet IL is overwhelmingly driven by highly positive entropies as a result of the release of a large amount of water molecules from the solvation sphere of U(VI). Moreover, comparisons between the fitted absorption spectra of complexes in wet IL and that of extractive samples from solvent extraction have identified the speciation involved in the extraction of U(VI) by CMPO in ionic liquid. The results from this study not only offer a thermodynamic insight into the complexation behavior of U(VI) with CMPO in IL but also provide valuable information for understanding the extraction behavior in the corresponding solvent extraction system.

Kinetics and Products of Chromium(VI) Reduction by Iron(II/III)-Bearing Clay Minerals.

PubMed

Joe-Wong, Claresta; Brown, Gordon E; Maher, Kate

2017-09-05

Hexavalent chromium is a water-soluble pollutant, the mobility of which can be controlled by reduction of Cr(VI) to less soluble, environmentally benign Cr(III). Iron(II/III)-bearing clay minerals are widespread potential reductants of Cr(VI), but the kinetics and pathways of Cr(VI) reduction by such clay minerals are poorly understood. We reacted aqueous Cr(VI) with two abiotically reduced clay minerals: an Fe-poor montmorillonite and an Fe-rich nontronite. The effects of ionic strength, pH, total Fe content, and the fraction of reduced structural Fe(II) [Fe(II)/Fe(total)] were examined. The last variable had the largest effect on Cr(VI) reduction kinetics: for both clay minerals, the rate constant of Cr(VI) reduction varies by more than 3 orders of magnitude with Fe(II)/Fe(total) and is described by a linear free energy relationship. Under all conditions examined, Cr and Fe K-edge X-ray absorption near-edge structure spectra show that the main Cr-bearing product is a Cr(III)-hydroxide and that Fe remains in the clay structure after reacting with Cr(VI). This study helps to quantify our understanding of the kinetics of Cr(VI) reduction by Fe(II/III)-bearing clay minerals and may improve predictions of Cr(VI) behavior in subsurface environments.

Study on Cr(VI) Leaching from Cement and Cement Composites

PubMed Central

Palascakova, Lenka; Kanuchova, Maria

2018-01-01

This paper reports an experimental study on hexavalent chromium leaching from cement samples and cement composites containing silica fume and zeolite additions that were subjected to various leaching agents. The water-soluble Cr(VI) concentrations in cements ranged from 0.2 to 3.2 mg/kg and represented only 1.8% of the total chromium content. The presence of chromium compounds with both chromium oxidation states of III and VI was detected in the cement samples by X-ray photoelectron spectroscopy (XPS). Leaching tests were performed in a Britton-Robinson buffer to simulate natural conditions and showed increased dissolution of Cr(VI) up to 6 mg/kg. The highest amount of leached hexavalent chromium was detected after leaching in HCl. The findings revealed that the leaching of chromium from cements was higher by 55–80% than that from the cement composites. A minimum concentration was observed for all cement samples when studying the relationship between the soluble Cr(VI) and the cement storage time. PMID:29690550

Study on Cr(VI) Leaching from Cement and Cement Composites.

PubMed

Estokova, Adriana; Palascakova, Lenka; Kanuchova, Maria

2018-04-22

This paper reports an experimental study on hexavalent chromium leaching from cement samples and cement composites containing silica fume and zeolite additions that were subjected to various leaching agents. The water-soluble Cr(VI) concentrations in cements ranged from 0.2 to 3.2 mg/kg and represented only 1.8% of the total chromium content. The presence of chromium compounds with both chromium oxidation states of III and VI was detected in the cement samples by X-ray photoelectron spectroscopy (XPS). Leaching tests were performed in a Britton-Robinson buffer to simulate natural conditions and showed increased dissolution of Cr(VI) up to 6 mg/kg. The highest amount of leached hexavalent chromium was detected after leaching in HCl. The findings revealed that the leaching of chromium from cements was higher by 55⁻80% than that from the cement composites. A minimum concentration was observed for all cement samples when studying the relationship between the soluble Cr(VI) and the cement storage time.

A critical review of ferrate(VI)-based remediation of soil and groundwater.

PubMed

Rai, Prabhat Kumar; Lee, Jechan; Kailasa, Suresh Kumar; Kwon, Eilhann E; Tsang, Yiu Fai; Ok, Yong Sik; Kim, Ki-Hyun

2018-01-01

Over the past few decades, diverse chemicals and materials such as mono- and bimetallic nanoparticles, metal oxides, and zeolites have been used for soil and groundwater remediation. Ferrate (Fe VI O 4 2- ) has been widely employed due to its high-valent iron (VI) oxo compound with high oxidation/reduction potentials. Ferrate has received attention for wide environmental applications including water purification and sewage sludge treatment. Ferrate provides great potential for diverse environmental applications without any environmental problems. Therefore, this paper provides comprehensive information on the recent progress on the use of (Fe VI O 4 2- ) as a green material for use in sustainable treatment processes, especially for soil and water remediation. We reviewed diverse synthesis recipes for ferrates (Fe VI O 4 2- ) and their associated physicochemical properties as oxidants, coagulants, and disinfectants for the elimination of a diverse range of chemical and biological species from water/wastewater samples. A summary of the eco-sustainable performance of ferrate(VI) in water remediation is also provided and the future of ferrate(VI) is discussed in this review. Copyright © 2017 Elsevier Inc. All rights reserved.

Probing chromium(III) from chromium(VI) in cells by a fluorescent sensor

NASA Astrophysics Data System (ADS)

Hu, Xiangquan; Chai, Jie; Liu, Yanfei; Liu, Bin; Yang, Binsheng

2016-01-01

Cellular uptake of Cr(VI), followed by its reduction to Cr(III) with the formation of kinetically inert Cr(III) complexes, is a complex process. To better understand its physiological and pathological functions, efficient methods for the monitoring of Cr(VI) are desired. In this paper a selective fluorescent probe L, rhodamine hydrazide bearing a benzo[b]furan-2-carboxaldehyde group, was demonstrated as a red chemosensor for Cr(III) at about 586 nm. This probe has been used to probe Cr(III) which is reduced from Cr(VI) by reductants such as glutathione (GSH), vitamin C, cysteine (Cys), H2O2 and Dithiothreitol (DTT) by fluorescence spectra. Cr(VI) metabolism in vivo is primarily driven by Vc and GSH. Vc could reduce CrO42 - to Cr(III) in a faster rate than GSH. The indirectly detection limit for Cr(VI) by L + GSH system was determined to be 0.06 μM at pH = 6.2. Moreover, the confocal microscopy image experiments indicated that Cr(VI) can be reduced to Cr(III) inside cells rapidly and the resulted Cr(III) can be captured and imaged timely by L.

VI-14, a novel flavonoid derivative, inhibits migration and invasion of human breast cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Fanni; Li, Chenglin; Zhang, Haiwei

It has been well characterized that flavonoids possess pronounced anticancer potentials including anti-angiogenesis, anti-metastasis, and pro-apoptosis. Herein, we report, for the first time, that VI-14, a novel flavonoid derivative, possesses anti-cancer properties. The purpose of this study is to investigate the anti-migration and anti-invasion activities of VI-14 in breast cancer cells. Our data indicate that VI-14 inhibits adhesion, migration and invasion of MDA-MB-231 and MDA-MB-435 human breast cancer cells. MDA-MB-231 cells treated with VI-14 display reduced activities and expressions of ECM degradation-associated proteins including matrix metalloproteinase 2 (MMP-2) and 9 (MMP-9) at both the protein and mRNA levels. Meanwhile, VI-14more » treatment induces an up-regulated expression of tissue inhibitor of metalloproteinase 1 (TIMP-1) and 2 (TIMP-2) in MDA-MB-231 cells. Western blotting results show that phosphorylation levels of critical components of the MAPK signaling pathway, including ERK, JNK and P38, are dramatically decreased in VI-14-treated MDA-MB-231 cells. Furthermore, treatment of VI-14 significantly decreases the nuclear levels and the binding ability of nuclear factor-kappa B (NF-κB) and activator protein-1 (AP-1). Taken together, our data suggest that VI-14 treatment suppresses migration and motility of breast cancer cells, and VI-14 may be a potential compound for cancer therapy. Highlights: ► We report for the first time that VI-14 possesses anti-cancer properties. ► VI-14 weakens the adhesion, migration and invasion of human breast cancer cells. ► VI-14 decreases the activities and expressions of MMP-2/9. ► VI-14 suppresses the phosphorylation levels of the MAPK signaling pathway. ► VI-14 decreases the nuclear levels and the binding ability of NF-κB and AP-1.« less

AM(VI) partitioning studies. FY14 final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mincher, Bruce J.

2014-10-01

The use of higher oxidation states of americium in partitioning from the lanthanides is under continued investigation by the sigma team. This is based on the hypothesis that Am(VI) can be produced and remain stable in irradiated first cycle raffinate solution long enough to perform solvent extraction for separations. The stability of Am(VI) to autoreduction was measured using millimolar americium concentrations in a 1-cm cell with a Cary 6000 UV/Vis spectrophotometer for data acquisition. At millimolar americium concentrations, Am(VI) is stable enough against its own autoreduction for separations purposes. A second major accomplishment during FY14 was the hot test. Americiummore » oxidation and extraction was performed using a centrifugal contactor-based test bed consisting of an extraction stage and two stripping stages. Sixty-three percent americium extraction was obtained in one extraction stage, in agreement with batch contacts. Promising electrochemical oxidation results have also been obtained, using terpyridine ligand derivatized electrodes for binding of Am(III). Approximately 50 % of the Am(III) was oxidized to Am(V) over the course of 1 hour. It is believed that this is the first demonstration of the electrolytic oxidation of americium in a non-complexing solution. Finally, an initial investigation of Am(VI) extraction using diethylhexylbutyramide (DEHBA) was performed.« less

Reaction kinetics and oxidation product formation in the degradation of acetaminophen by ferrate (VI).

PubMed

Wang, Hongyu; Liu, Yibing; Jiang, Jia-Qian

2016-07-01

This paper investigates the degradation of acetaminophen (AAP) in aqueous solutions by ferrate (VI), aiming to propose the kinetics, pathways and the oxidation products' formation in the AAP degradation. A series of jar tests were undertaken over ferrate (VI) dosages (molar ratios of ferrate (VI):AAP, 5:1 to 25:1) and pH values (4-11). The effects of co-existing ions (0.2-5 mM) and humic acid (10-50 mg l(-1)) on the AAP removal were investigated. Ferrate (VI) can remove 99.6% AAP (from 1000 μg l(-1)) in 60 min under study conditions when majority of the AAP reduction occurred in the first 5 min. The treatment performance depended on the ferrate(VI) dosage, pH and the type and strength of co-existing ions and humic acid. Raising ferrate (VI) dosage with optimal pH 7 improved the AAP degradation. In the presence of humic acid, the AAP degradation by ferrate (VI) was promoted in a short period (<30 min) but then inhibited with increasing in humic acid contents. The presence of Al(3+), CO3(2-) and PO4(3-) ions declined but the existence of K(+), Na(+), Mg(2+) and Ca(2+) ions can improve the AAP removal. The catalytic function of Al(3+) on the decomposition of ferrate (VI) in aqueous solution was found. The kinetics of the reaction between ferrate (VI) and AAP was pseudo first-order for ferrete (VI) and pseudo second-order for AAP. The pseudo rate constant of ferrate (VI) with AAP was 1.4 × 10(-5) L(2) mg(-2) min(-1). Three oxidation products (OPs) were identified and the AAP degradation pathways were proposed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Group I-III-VI.sub.2 semiconductor films for solar cell application

DOEpatents

Basol, Bulent M.; Kapur, Vijay K.

1991-01-01

This invention relates to an improved thin film solar cell with excellent electrical and mechanical integrity. The device comprises a substrate, a Group I-III-VI.sub.2 semiconductor absorber layer and a transparent window layer. The mechanical bond between the substrate and the Group I-III-VI.sub.2 semiconductor layer is enhanced by an intermediate layer between the substrate and the Group I-III-VI.sub.2 semiconductor film being grown. The intermediate layer contains tellurium or substitutes therefor, such as Se, Sn, or Pb. The intermediate layer improves the morphology and electrical characteristics of the Group I-III-VI.sub.2 semiconductor layer.

On the Stark broadening of Cr VI spectral lines in astrophysical plasma

NASA Astrophysics Data System (ADS)

Dimitrijević, M. S.; Simić, Z.; Sahal-Bréchot, S.

2017-02-01

Stark broadening parameters for Cr VI lines have been calculated using semiclassical perturbation method for conditions of interest for stellar plasma. Here are presented, as an example of obtained results, Stark broadening parameters for electron- and proton-impact broadening for Cr VI 4s 2S-4p 2P° λ = 1430 Å and Cr VI 4p 2P°-5s 2S λ = 611.8 Å multiplets. The obtained results are used to demonstrate the importance of Stark broadening of Cr VI in DO white dwarf atmospheres. Also the obtained results will enter in STARK-B database which is included in Virtual Atomic and Molecula Data Center - VAMDC.

Characterization of U(VI) reduction in contaminated sediments with slow-degrading electron donor source

NASA Astrophysics Data System (ADS)

Wu, W.; Watson, D. B.; Zhang, G.; Mehlhorn, T.; Lowe, K.; Earles, J.; Phillips, J.; Kelly, S. D.; Boyanov, M.; Kemner, K. M.; Schadt, C.; Criddle, C. S.; Jardine, P. M.; Brooks, S. C.

2011-12-01

In order to select sustainable, high efficiency and cost effective electron donor source, oleate and emulsified vegetable oil (EVO) were tested uranium (VI) reduction in comparison with ethanol in microcosms using uranium contaminated sediments and groundwater from the US DOE Oak Ridge Integrated Field Research Challenge (ORIFRC) site. The effect of initial sulfate concentration on U(VI) reduction was also tested. Both oleate and EVO were effective electron donor sources for U(VI) reduction. Accumulation of acetate as a major product and the removal of aqueous U(VI) were observed and were associated with sulfate reduction. Both oleate and EVO supported U(VI) reduction but at slower rates with a comparable but slightly lower extent of reduction than ethanol. X-ray absorption near-edge spectroscopy (XANES) analysis confirmed reduction of U(VI) to U(IV). The extent of U(VI) reduction in solid phase was negatively influenced by aqueous calcium concentration. The majority of electrons of the three substrates were consumed by sulfate reduction, Fe(III) reduction, and methanogenesis. Initial U(VI) concentration in the aqueous phase increased with increased sulfate concentration (1 versus 5 mM), likely due to U(VI) desorption from the solid phase. At the higher initial sulfate concentration more U(VI) was reduced and fewer electrons were used in methanogenesis. Analysis of bacterial and archeal populations using 16S rRNA gene libraries showed a significant increase in Deltaproteobacteria after biostimulation. The microbial community structures developed with oleate and EVO were significantly distinct from those developed with ethanol. Bacteria similar to Desulforegula spp. was predominant for oleate and EVO degradation but were not observed in ethanol-amended microcosms. Known U(VI)-reducing bacteria in the microcosms amended with the three electron donor sources included iron(III) reducing Geobacter spp. but in lower abundances than sulfate-reducing Desulfovibrio spp. The

Diffusion of U(VI) in Opalinus Clay: Influence of temperature and humic acid

NASA Astrophysics Data System (ADS)

Joseph, C.; Van Loon, L. R.; Jakob, A.; Steudtner, R.; Schmeide, K.; Sachs, S.; Bernhard, G.

2013-05-01

The diffusion of U(VI) (c0 = 1 × 10-6 mol/L) in compacted Opalinus Clay from the Mont Terri underground laboratory, Switzerland, was studied in the absence and presence of humic acid (10 mg/L) at two different temperatures (25 °C, 60 °C) under anaerobic conditions. As background electrolyte synthetic Opalinus Clay pore water (pH 7.6, I = 0.36 mol/L) was used. The diffusion-accessible porosity, ɛ, was determined for each Opalinus Clay bore core sample by through-diffusion experiments with tritiated water (HTO) before the U(VI) diffusion experiments were carried out. The values for the effective diffusion and distribution coefficients De and Kd obtained for U(VI) and humic acid at 25 °C as well as at 60 °C showed that humic acid has no significant influence on the U(VI) diffusion. The diffusion profiles of humic acid in Opalinus Clay at 25 and 60 °C indicate the contributions of two different humic acid particle size fractions (<1 kDa and 10-100 kDa). The small-sized humic acid fraction diffused through the whole Opalinus Clay samples at both temperatures within the 3 month duration of the U(VI) diffusion experiments. At 60 °C, diffusion profiles of two different U(VI) species were observed. In a separate experiment the U(VI) speciation in the source reservoir solution at 60 °C was analyzed by laser-induced fluorescence spectroscopy, photon correlation spectroscopy and scanning electron microscopy with an energy dispersive X-ray detector. The two diffusion profiles could be attributed to an unknown colloidal and a known aquatic U(VI) species (Ca2UO2(CO3)3(aq)). The diffusion results showed that the interaction of U(VI) and of the large-sized humic acid colloid fraction with the clay is stronger at 60 °C. An increase of Kd from 0.025 ± 0.003 m3/kg at 25 °C to 0.25 ± 0.05 m3/kg for U(VI)colloidal at 60 °C was determined. In addition, the value for De of U(VI) increased with increasing temperature. Using the De values at 25 and 60 °C, a preliminary

Sero-efficacy of Vi-polysaccharide tetanus-toxoid typhoid conjugate vaccine (Typbar-TCV).

PubMed

Voysey, Merryn; Pollard, Andrew J

2018-01-17

Salmonella Typhi is the major cause of enteric fever in lower income countries. New conjugate vaccines show promise as public health interventions, however there are no efficacy data available from endemic areas. Data were obtained from a previously published phase 3 randomised controlled trial comparing Vi-polysaccharide tetanus-toxoid conjugate vaccine (Typbar-TCV; Bharat Biotech Intl Ltd, India): (Vi-TT) with Vi-polysaccharide (Typbar; Bharat Biotech Intl Ltd, India): (Vi-PS) in participants aged 2- 45 years. An additional open-label arm administered Vi-TT to children aged 6 months to 23 months. The proportion of participants with presumed clinical or subclinical infection ('seroincidence'), was determined using mixture models and compared using relative risks. 81/387 (21%) participants were classified as having presumed typhoid infection during the 2 year period post-vaccination. Seroincidence was lower in those randomised to Vi-TT than Vi-PS in those aged 2-45 years; 21/155 (13.5%) vs 47/129 (36.4%); RR 0.372 (95%CI 0.235-0.588), p<0.0001 and in those aged 2-15 years RR 0.424 (95%CI 0.231-0.778), p=0.0039. There was no difference in seroincidence in those receiving Vi-TT aged 2-45 years and those aged 6-23 months; 21/155 (13.5%) vs 13/103 (12.6%); RR 1.073 (0.563, 2.046), p=0.8293. Vaccine seroefficacy was 85% (95%CI 80-88%). This is the first field estimate of the seroefficacy of a Vi-TT vaccine and shows that Typbar TCV substantially reduces the number of serologically defined (sub)clinical infections in infants, children and adults. These results support the recent World Health Organisation recommendations for deployment of typhoid conjugate vaccines in high burden areas. © The Author(s) 2018. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.

ESL VI Curriculum Guide.

ERIC Educational Resources Information Center

Flander, Leonard

This curriculum guide for English as a Second Language (ESL) Level VI is the sixth of six in a Guam Community College ESL project series. The other five guides, a companion teacher's guide and pre- and post-tests are available separately (see note). The entire project centers around the Peabody Kits P, Level P, Level 1, Level 2, Level 3, and the…

Ferrate(VI) as a greener oxidant: Electrochemical generation and treatment of phenol.

PubMed

Sun, Xuhui; Zhang, Qi; Liang, He; Ying, Li; Xiangxu, Meng; Sharma, Virender K

2016-12-05

Ferrate(VI) (Fe(VI)O4(2-), Fe(VI)) is a greener oxidant in the treatment of drinking water and wastewater. The electrochemical synthesis of Fe(VI) may be considered environmentally friendly because it involves one-step process to convert Fe(0) to Fe(VI) without using harmful chemicals. Electrolysis was performed by using a sponge iron as an anode in NaOH solution at different ionic strengths. The cyclic voltammetric (CV) curves showed that the sponge iron had higher electrical activity than the grey cast iron. The optimum current density was 0.054mAcm(-2) in 10M NaOH solution, which is much lower than the electrolyte concentrations used in other electrode materials. A comparison of current efficiency and energy consumption was conducted and is briefly discussed. The generated ferrate solution was applied to degrade phenol in water at two levels (2mgL(-1) and 5mgL(-1)). The maximum removal efficiency was ∼70% and the optimum pH for phenol treatment was 9.0. Experiments on phenol removal using conventional coagulants (ferric chloride (FeCl3) and polyaluminium chloride (PAC)) were performed independently to demonstrate that removal of phenol by Fe(VI) occurred mainly by oxidative transformation. A combination of Fe(VI) and coagulant may be advantageous in enhancing removal efficiency, adjusting pH, and facilitating flocculation. Copyright © 2015 Elsevier B.V. All rights reserved.

The O VI Mystery: Mismatch between X-Ray and UV Column Densities

NASA Astrophysics Data System (ADS)

Mathur, S.; Nicastro, F.; Gupta, A.; Krongold, Y.; McLaughlin, B. M.; Brickhouse, N.; Pradhan, A.

2017-12-01

The UV spectra of Galactic and extragalactic sightlines often show O VI absorption lines at a range of redshifts, and from a variety of sources from the Galactic circumgalactic medium to active galactic nuclei (AGN) outflows. Inner shell O VI absorption is also observed in X-ray spectra (at λ =22.03 Å), but the column density inferred from the X-ray line was consistently larger than that from the UV line. Here we present a solution to this discrepancy for the z = 0 systems. The O II Kβ line {}4{S}0\\to {(}3D)3{p}4P at 562.40 eV (≡22.04 Å) is blended with the O VI Kα line in X-ray spectra. We estimate the strength of this O II line in two different ways, and show that in most cases the O II line accounts for the entire blended line. The small amount of O VI equivalent width present in some cases has column density entirely consistent with the UV value. This solution to the O VI discrepancy, however, does not apply to high column-density systems like AGN outflows. We discuss other possible causes to explain their UV/X-ray mismatch. The O VI and O II lines will be resolved by gratings on board the proposed mission Arcus and the concept mission Lynx, and would allow the detection of weak O VI lines not just at z = 0, but also at higher redshift.

Chromium VI and stomach cancer: a meta-analysis of the current epidemiological evidence.

PubMed

Welling, Roberta; Beaumont, James J; Petersen, Scott J; Alexeeff, George V; Steinmaus, Craig

2015-02-01

Chromium VI (hexavalent chromium, Cr(VI)) is an established cause of lung cancer, but its association with gastrointestinal cancer is less clear. The goal of this study was to examine whether the current human epidemiological research on occupationally inhaled Cr(VI) supports the hypothesis that Cr(VI) is associated with human stomach cancer. Following a thorough literature search and review of individual studies, we used meta-analysis to summarise the current epidemiological literature on inhaled Cr(VI) and stomach cancer, explore major sources of heterogeneity, and assess other elements of causal inference. We identified 56 cohort and case-control studies and 74 individual relative risk (RR) estimates on stomach cancer and Cr(VI) exposure or work in an occupation associated with high Cr(VI) exposure including chromium production, chrome plating, leather work and work with Portland cement. The summary RR for all studies combined was 1.27 (95% CI 1.18 to 1.38). In analyses limited to only those studies identifying increased risks of lung cancer, the summary RR for stomach cancer was higher (RR=1.41, 95% CI 1.18 to 1.69). Overall, these results suggest that Cr(VI) is a stomach carcinogen in humans, which is consistent with the tumour results reported in rodent studies. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

GeoViQua: quality-aware geospatial data discovery and evaluation

NASA Astrophysics Data System (ADS)

Bigagli, L.; Papeschi, F.; Mazzetti, P.; Nativi, S.

2012-04-01

GeoViQua (QUAlity aware VIsualization for the Global Earth Observation System of Systems) is a recently started FP7 project aiming at complementing the Global Earth Observation System of Systems (GEOSS) with rigorous data quality specifications and quality-aware capabilities, in order to improve reliability in scientific studies and policy decision-making. GeoViQua main scientific and technical objective is to enhance the GEOSS Common Infrastructure (GCI) providing the user community with innovative quality-aware search and evaluation tools, which will be integrated in the GEO-Portal, as well as made available to other end-user interfaces. To this end, GeoViQua will promote the extension of the current standard metadata for geographic information with accurate and expressive quality indicators, also contributing to the definition of a quality label (GEOLabel). GeoViQua proposed solutions will be assessed in several pilot case studies covering the whole Earth Observation chain, from remote sensing acquisition to data processing, to applications in the main GEOSS Societal Benefit Areas. This work presents the preliminary results of GeoViQua Work Package 4 "Enhanced geo-search tools" (WP4), started in January 2012. Its major anticipated technical innovations are search and evaluation tools that communicate and exploit data quality information from the GCI. In particular, GeoViQua will investigate a graphical search interface featuring a coherent and meaningful aggregation of statistics and metadata summaries (e.g. in the form of tables, charts), thus enabling end users to leverage quality constraints for data discovery and evaluation. Preparatory work on WP4 requirements indicated that users need the "best" data for their purpose, implying a high degree of subjectivity in judgment. This suggests that the GeoViQua system should exploit a combination of provider-generated metadata (objective indicators such as summary statistics), system-generated metadata (contextual

A Salmonella Typhimurium-Typhi Genomic Chimera: A Model to Study Vi Polysaccharide Capsule Function In Vivo

PubMed Central

Clare, Simon; Goulding, David; Holt, Kathryn E.; Grant, Andrew J.; Mastroeni, Piero; Dougan, Gordon; Kingsley, Robert A.

2011-01-01

The Vi capsular polysaccharide is a virulence-associated factor expressed by Salmonella enterica serotype Typhi but absent from virtually all other Salmonella serotypes. In order to study this determinant in vivo, we characterised a Vi-positive S. Typhimurium (C5.507 Vi+), harbouring the Salmonella pathogenicity island (SPI)-7, which encodes the Vi locus. S. Typhimurium C5.507 Vi+ colonised and persisted in mice at similar levels compared to the parent strain, S. Typhimurium C5. However, the innate immune response to infection with C5.507 Vi+ and SGB1, an isogenic derivative not expressing Vi, differed markedly. Infection with C5.507 Vi+ resulted in a significant reduction in cellular trafficking of innate immune cells, including PMN and NK cells, compared to SGB1 Vi− infected animals. C5.507 Vi+ infection stimulated reduced numbers of TNF-α, MIP-2 and perforin producing cells compared to SGB1 Vi−. The modulating effect associated with Vi was not observed in MyD88−/− and was reduced in TLR4−/− mice. The presence of the Vi capsule also correlated with induction of the anti-inflammatory cytokine IL-10 in vivo, a factor that impacted on chemotaxis and the activation of immune cells in vitro. PMID:21829346

Ferric chloride modified zeolite in wastewater on Cr (VI) adsorption characteristics

NASA Astrophysics Data System (ADS)

Wu, Xiaoqing; Zhang, Kang; Chen, Wen; Zhang, Hua

2018-03-01

Zeolite was modified by ferric chloride(Fe-Z) removal Cr (VI) ion from wastewater. The results showed that the effect of Cr(VI) adsorption on modified zeolite depended significantly on pH. It is favorable for the adsorption of Cr(VI) in acid condition. The Langmuir isotherm model has high fitting accuracy with experimental data, demonstrated that is monolayer adsorption and chemical adsorption.The pseudo-second-order equation provided the best correlation to the data. The model can describe the adsorption reaction process well.

Aqueous solubility of Cr(VI) compounds in ferrochrome bag filter dust and the implications thereof

DOE PAGES

Du Preez, S. P.; Beukes, J. P.; Van Dalen, W. P. J.; ...

2017-04-21

The production of ferrochrome (FeCr) is a reducing process. However, it is impossible to completely exclude oxygen from all of the high-temperature production process steps, which may lead to unintentional formation of small amounts of Cr(VI). The majority of Cr(VI) is associated with particles found in the off-gas of the high-temperature processes, which are cleaned by means of venturi scrubbers or bag filter dust (BFD) systems. BFD contains the highest concentration of Cr(VI) of all FeCr wastes. In this study, the solubility of Cr(VI) present in BFD was determined by evaluating four different BFD samples. The results indicate that themore » currently applied Cr(VI) treatment strategies of the FeCr producer (with process water pH ≤ 9) only effectively extract and treat the water-soluble Cr(VI) compounds, which merely represented approximately 31% of the total Cr(VI) present in the BFD samples evaluated. Extended extraction time, within the afore-mentioned pH range, proved futile in extracting sparingly-soluble and water-insoluble Cr(VI) species, which represented approximately 34% and 35% of the total Cr(VI), respectively. Due to the deficiencies of the current treatment strategies, it is highly likely that sparingly water-soluble Cr(VI) compounds will leach from waste storage facilities (e.g. slimes dams) over time. Therefore, it is critical that improved Cr(VI) treatment strategies be formulated, which should be an important future perspective for FeCr producers and researchers alike.« less

Chromium (VI) purification using pine sawdust in batch systems

NASA Astrophysics Data System (ADS)

Politi, Dorothea; Sidiras, Dimitris

2012-12-01

Pine sawdust, a waste generated in furniture industry, has been used as low-cost potential adsorbent. This low-cost adsorbent was used for the removal of chromium (VI) from an aqueous solution. The kinetics of adsorption and extent of adsorption at equilibrium are dependent on the physical and chemical characteristics of the adsorbent and adsorbate. The effect of hydrogen ion concentration, contact time, adsorbent dose and initial concentration of adsorbate on the uptake of chromium were studied in batch experiments. The adsorption data has been correlated with Lagergren - Eldridge pseudofirst order kinetic model. The efficiency of adsorbent material for the removal of Cr(VI) was found to be between 13.1 and 95.6%, respectively. These results depend on the conditions of pH, contact time, sawdust dose and Cr(VI) concentration.

Experiments indicating a second hydrogen ordered phase of ice VI

PubMed Central

Gasser, Tobias M.; Thoeny, Alexander V.; Plaga, Lucie J.; Köster, Karsten W.; Etter, Martin; Böhmer, Roland

2018-01-01

In the last twelve years five new ice phases were experimentally prepared. Two of them are empty clathrate hydrates and three of them represent hydrogen ordered counterparts of previously known disordered ice phases. Here, we report on hydrogen ordering in ice VI samples produced by cooling at pressures up to 2.00 GPa. Based on results from calorimetry, dielectric relaxation spectroscopy, Raman spectroscopy, and powder X-ray diffraction the existence of a second hydrogen ordered polymorph related to ice VI is suggested. Powder X-ray data show the oxygen network to be the one of ice VI. For the 1.80 GPa sample the activation energy from dielectric spectroscopy is 45 kJ mol–1, which is much larger than for the known hydrogen ordered proxy of ice VI, ice XV. Raman spectroscopy indicates the 1.80 GPa sample to be more ordered than ice XV. It is further distinct from ice XV in that it experiences hydrogen disordering above ≈103 K which is 26 K below the ice XV to ice VI disordering transition. Consequently, below 103 K it is thermodynamically more stable than ice XV, adding a stability region to the phase diagram of water. For the time being we suggest to call this new phase ice β-XV and to relabel it ice XVIII once its crystal structure is known. PMID:29780552

Experiments indicating a second hydrogen ordered phase of ice VI.

PubMed

Gasser, Tobias M; Thoeny, Alexander V; Plaga, Lucie J; Köster, Karsten W; Etter, Martin; Böhmer, Roland; Loerting, Thomas

2018-05-14

In the last twelve years five new ice phases were experimentally prepared. Two of them are empty clathrate hydrates and three of them represent hydrogen ordered counterparts of previously known disordered ice phases. Here, we report on hydrogen ordering in ice VI samples produced by cooling at pressures up to 2.00 GPa. Based on results from calorimetry, dielectric relaxation spectroscopy, Raman spectroscopy, and powder X-ray diffraction the existence of a second hydrogen ordered polymorph related to ice VI is suggested. Powder X-ray data show the oxygen network to be the one of ice VI. For the 1.80 GPa sample the activation energy from dielectric spectroscopy is 45 kJ mol -1 , which is much larger than for the known hydrogen ordered proxy of ice VI, ice XV. Raman spectroscopy indicates the 1.80 GPa sample to be more ordered than ice XV. It is further distinct from ice XV in that it experiences hydrogen disordering above ≈103 K which is 26 K below the ice XV to ice VI disordering transition. Consequently, below 103 K it is thermodynamically more stable than ice XV, adding a stability region to the phase diagram of water. For the time being we suggest to call this new phase ice β-XV and to relabel it ice XVIII once its crystal structure is known.

Spectroscopic confirmation of uranium(VI)-carbonato adsorption complexes on hematite

USGS Publications Warehouse

Bargar, John R.; Reitmeyer, Rebecca; Davis, James A.

1999-01-01

Evaluating societal risks posed by uranium contamination from waste management facilities, mining sites, and heavy industry requires knowledge about uranium transport in groundwater, often the most significant pathway of exposure to humans. It has been proposed that uranium mobility in aquifers may be controlled by adsorption of U(VI)−carbonato complexes on oxide minerals. The existence of such complexes has not been demonstrated, and little is known about their compositions and reaction stoichiometries. We have used attenuated total reflectance Fourier transform infrared (ATR-FTIR) and extended X-ray absorption fine structure (EXAFS) spectroscopies to probe the existence, structures, and compositions of ≡FeOsurface−U(VI)−carbonato complexes on hematite throughout the pH range of uranyl uptake under conditions relevant to aquifers. U(VI)−carbonato complexes were found to be the predominant adsorbed U(VI) species at all pH values examined, a much wider pH range than previously postulated based on analogy to aqueous U(VI)−carbonato complexes, which are trace constituents at pH < 6. This result indicates the inadequacy of the common modeling assumption that the compositions and predominance of adsorbed species can be inferred from aqueous species. By extension, adsorbed carbonato complexes may be of major importance to the groundwater transport of similar actinide contaminants such as neptunium and plutonium.

[Adsorptive Stabilization of Soil Cr (VI) Using HDTMA Modified Montmorillonite].

PubMed

2016-03-15

A series of organo-montomorillonites were prepared using Na-montomorillonite and hexadecyl trimethyl ammonium bromide (HDTMA). The organo-montomorillonites were then investigated for the remediation of Cr(VI) contaminated soils. FT-IR, XRD, SEM and N2 -BET, CEC, Zeta potential measurement were conducted to understand the structural changes of montmorillonites as different amounts of HDTMAs were added as modifier. The characterization results indicated that the clay interlayer spacing distance increased from 1. 25 nm to 2. 13 nm, the clay surface roughness decreased, the clay surface area reduced from 38.91 m² · g⁻¹ to 0.42 m² · g⁻¹, the clay exchangeable cation amount reduced from 62 cmol · kg⁻¹ to 9.9 cmol · kg⁻¹ and the clay surface charge changed from -29.1 mV to 5.59 mV as the dosage of HDTMA in montmorillonite was increased. The TCLP (toxicity characteristic leaching procedure) was used to evaluate the leachate toxicity of Cr(VI). The effects of the initial soil Cr(VI) concentration, montmorillonites dosage, reaction time and HDTMA modification amount were investigated, respectively. The results revealed that modification of montmorillonites would manifest an attenuated physical adsorptive effect and an enhanced electrostatic adsorptive effect on Cr(VI), suggesting electrostatic effect was the major force that resulted in improved Cr(VI) adsorption onto HDTMA modified montmorillonites.

Remediation of chromium-slag leakage with electricity cogeneration via a urea-Cr(VI) cell

PubMed Central

Yu, Binbin; Zhang, Huimin; Xu, Wei; Li, Gang; Wu, Zucheng

2014-01-01

Chromium pollution has been historically widespread throughout the world. Most available remediation technologies often require energy consumption. This study is aimed to develop electrochemical remediation for Cr(VI) in chromium-slag leakage with self-generated electricity. Dynamic leaching experiments of chromium-slag samples were conducted to survey the release and leaching behavior of Cr(VI). Based on previous work, a unique urea-Cr(VI) was designed, in which urea was employed as the fuel and Cr(VI) from the leakage of the dichromate slag served as the oxidant. Furthermore, the electrochemical results showed that the removal percent of Cr(VI) was more than 96% after 18 h with the leakage Cr(VI) concentration of 2.69 mM. The open circuit potential (OCP) varied in the range of 1.56 ~ 1.59 V under different initial Cr(VI) leakage concentrations. The approach explores the feasibility of the promising technique without the need of energy input for simultaneous chromium-slag remediation and generation of electricity. PMID:25168513

Reduction of toxic Cr(VI)-humic acid in an ionic liquid

NASA Astrophysics Data System (ADS)

Huang, Hsin-Liang; Huang, Hsin-Hung; Wei, Yu Jhe

2017-07-01

Remediation of soil contaminated by toxic hexavalent chromium species associated with humic acid (Cr(VI)-HA) and absorbed Cr(VI) in pores frequently experiences technical difficulties. In the present work, a feasibility study for extraction of the Cr(VI) species from a molecular sieve MCM-41 (Mobil Composition of Matter No. 41) that was used to simulate the pore system of soil, with a green solvent (ionic liquid), 1-butyl-3-methylimidazolium chloride ([C4mim][Cl]), was carried out. After a 30-min extraction, approximately 70% of the Cr(VI) species can be extracted. By component fitted X-ray absorption near edge structure (XANES) spectroscopy, about 48% of the Cr(VI)-HA are reduced to form less toxic species (Cr(III)-HA) during extraction with [C4mim][Cl]. Note that the Cr-O in the [C4mim][Cl] phase has a slightly greater bond distance (BD) (0.162 nm) possibly due to the fact of that the fraction of Cr(III) is increased in the extraction process. The non-extractable chromium remaining in MCM-41 has a much greater fraction of Cr(III) (78%) and its BD is further increased to 0.195 nm. The coordination numbers of chromium for the 1st shell Cr-O in the Cr(VI) and Cr(III) species are in the range of 2.4-2.9, suggesting that chromium is chelated with HA and adsorbed in MCM-41. The 1H NMR data also suggest that the enhanced reduction of the Cr(VI) species may be related to interactions between chromium species and electron-rich imidazole ring of the [C4mim]+. This work also exemplifies that the fate of toxic chromium species in the complicated remediation of contaminated soils can be revealed in a molecule-scale study by synchrotron X-ray absorption spectroscopy.

Bacterial reduction of Cr(VI) at technical scale--the Malaysian experience.

PubMed

Zakaria, Zainul Akmar; Ahmad, Wan Azlina; Zakaria, Zainoha; Razali, Firdausi; Karim, Norsuhada Abdul; Sum, Mohamad Md; Sidek, Mohd Saufi Mohd

2012-07-01

The bacterial reduction of Cr(VI) from industrial wastewater was evaluated using a 2.0-m(3) bioreactor. Liquid pineapple waste was used as a nutrient for the biofilm community formed inside the bioreactor. The use of rubber wood sawdust as packing material was able to immobilize more than 10(6) CFU mL(-1) of Acinetobacter haemolyticus cells after 3 days of contact time. Complete reduction of 15-240 mg L(-1) of Cr(VI) was achieved even after 3 months of bioreactor operation. Cr(VI) was not detected in the final effluent fraction indicating complete removal of Cr from solution from the flocculation/coagulation step and the unlikely re-oxidation of Cr(III) into Cr(VI). Impatiens balsamina L. and Gomphrena globosa L. showed better growth in the presence of soil-sludge mixture compared to Coleus scutellarioides (L.) Benth. Significant amounts of Cr accumulated at different sections of the plants indicate its potential application in Cr phytoremediation effort. The bacterial-based system was also determined not to be detrimental to human health based on the low levels of Cr detected in the hair and nail samples of the plant operators. Thus, it can be said that bacterial-based Cr(VI) treatment system is a feasible alternative to the conventional system especially for lower Cr(VI) concentrations, where sludge generated can be used as growth supplement for ornamental plant as well as not detrimental to the health of the workers.

Fate of Adsorbed U(VI) during Sulfidization of Lepidocrocite and Hematite

PubMed Central

2017-01-01

The impact on U(VI) adsorbed to lepidocrocite (γ-FeOOH) and hematite (α-Fe2O3) was assessed when exposed to aqueous sulfide (S(-II)aq) at pH 8.0. With both minerals, competition between S(-II) and U(VI) for surface sites caused instantaneous release of adsorbed U(VI). Compared to lepidocrocite, consumption of S(-II)aq proceeded slower with hematite, but yielded maximum dissolved U concentrations that were more than 10 times higher, representing about one-third of the initially adsorbed U. Prolonged presence of S(-II)aq in experiments with hematite in combination with a larger release of adsorbed U(VI), enhanced the reduction of U(VI): after 24 h of reaction about 60–70% of U was in the form of U(IV), much higher than the 25% detected in the lepidocrocite suspensions. X-ray absorption spectra indicated that U(IV) in both hematite and lepidocrocite suspensions was not in the form of uraninite (UO2). Upon exposure to oxygen only part of U(IV) reoxidized, suggesting that monomeric U(IV) might have become incorporated in newly formed iron precipitates. Hence, sulfidization of Fe oxides can have diverse consequences for U mobility: in short-term, desorption of U(VI) increases U mobility, while reduction to U(IV) and its possible incorporation in Fe transformation products may lead to long-term U immobilization. PMID:28121137

Determination of free polysaccharide in Vi glycoconjugate vaccine against typhoid fever.

PubMed

Giannelli, C; Cappelletti, E; Di Benedetto, R; Pippi, F; Arcuri, M; Di Cioccio, V; Martin, L B; Saul, A; Micoli, F

2017-05-30

Glycoconjugate vaccines based on the Vi capsular polysaccharide directed against Salmonella enterica serovar Typhi are licensed or in development against typhoid fever, an important cause of morbidity and mortality in developing countries. Quantification of free polysaccharide in conjugate vaccines is an important quality control for release, to monitor vaccine stability and to ensure appropriate immune response. However, we found that existing separation methods based on size are not appropriate as free Vi non-specifically binds to unconjugated and conjugated protein. We developed a method based on free Vi separation by Capto Adhere resin and quantification by HPAEC-PAD. The method has been tested for conjugates of Vi derived from Citrobacter freundii with different carrier proteins such as CRM 197 , Tetanus Toxoid and Diphtheria Toxoid. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Removal of Cr(VI) from Aqueous Environments Using Micelle-Clay Adsorption

PubMed Central

Qurie, Mohannad; Khamis, Mustafa; Manassra, Adnan; Ayyad, Ibrahim; Nir, Shlomo; Scrano, Laura; Bufo, Sabino A.; Karaman, Rafik

2013-01-01

Removal of Cr(VI) from aqueous solutions under different conditions was investigated using either clay (montmorillonite) or micelle-clay complex, the last obtained by adsorbing critical micelle concentration of octadecyltrimethylammonium ions onto montmorillonite. Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI) from aqueous solutions. Langmuir adsorption isotherm fitted the experimental data giving significant results. Filtration experiments using columns filled with micelle-clay complex mixed with sand were performed to assess Cr(VI) removal efficiency under continuous flow at different pH values. The micelle-clay complex used in this study was capable of removing Cr(VI) from aqueous solutions without any prior acidification of the sample. Results demonstrated that the removal effectiveness reached nearly 100% when using optimal conditions for both batch and continuous flow techniques. PMID:24222757

Study of sorption-retarded U(VI) diffusion in Hanford silt/clay material.

PubMed

Bai, Jing; Liu, Chongxuan; Ball, William P

2009-10-15

A diffusion cell method was applied to measure the effective pore diffusion coefficient (Dp) for U(VI) under strictly controlled chemical conditions in a silt/clay sediment from the U.S. Department of Energy Hanford site, WA. "Inward-flux" diffusion studies were conducted in which [U(VI)] in both aqueous and solid phases was measured as a function of distance in the diffusion cell under conditions of constant concentration at the cell boundaries. A sequential extraction method was developed to measure sorbed contaminant U(VI) in the solid phase containing extractable background U(VI). The effect of sorption kinetics on U(VI) interparticle diffusion was evaluated by comparing sorption-retarded diffusion models with sorption described either as equilibrium or intraparticle diffusion-limited processes. Both experimental and modeling results indicated that (1) a single pore diffusion coefficient can simulate the diffusion of total aqueous U(VI), and (2) the local equilibrium assumption (LEA) is appropriate for modeling sorption-retarded diffusion under the given experimental conditions. Dp of 1.6-1.7 x 10(-6) cm2/s was estimated in aqueous solution at pH 8.0 and saturated with respect to calcite, as relevant to some subsurface regions of the Hanford site.

Chromium isotope variation along a contaminated groundwater plume: a coupled Cr(VI)- reduction, advective mixing perspective

NASA Astrophysics Data System (ADS)

Bullen, T.; Izbicki, J.

2007-12-01

Chromium (Cr) is a common contaminant in groundwater, used in electroplating, leather tanning, wood preservation, and as an anti-corrosion agent. Cr occurs in two oxidation states in groundwater: Cr(VI) is highly soluble and mobile, and is a carcinogen; Cr(III) is generally insoluble, immobile and less toxic than Cr(VI). Reduction of Cr(VI) to Cr(III) is thus a central issue in approaches to Cr(VI) contaminant remediation in aquifers. Aqueous Cr(VI) occurs mainly as the chromate (CrO22-) and bichromate (HCrO2-) oxyanions, while Cr(III) is mainly "hexaquo" Cr(H2O)63+. Cr has four naturally-occurring stable isotopes: 50Cr, 52Cr, 53Cr and 54Cr. When Cr(VI) is reduced to Cr(III), the strong Cr-O bond must be broken, resulting in isotopic selection. Ellis et al. (2002) demonstrated that for reduction of Cr(VI) on magnetite and in natural sediment slurries, the change of isotopic composition of the remnant Cr(VI) pool was described by a Rayleigh fractionation model having fractionation factor ɛCr(VI)-Cr(III) = 3.4‰. We attempted to use Cr isotopes as a monitor of Cr(VI) reduction at a field site in Hinkley, California (USA) where groundwater contaminated with Cr(VI) has been under assessment for remediation. Groundwater containing up to 5 ppm Cr(VI) has migrated down-gradient from the contamination source through the fluvial to alluvial sediments to form a well-defined plume. Uncontaminated groundwater in the aquifer immediately adjacent to the plume has naturally-occurring Cr(VI) of 4 ppb or less (CH2M-Hill). In early 2006, colleagues from CH2M-Hill collected 17 samples of groundwater from within and adjacent to the plume. On a plot of δ53Cr vs. log Cr(VI), the data array is strikingly linear and differs markedly from the trend predicted for reduction of Cr(VI) in the contaminated water. There appear to be two groups of data: four samples with δ53Cr >+2‰ and Cr(VI) <4 ppb, and 13 samples with δ53Cr <+2‰ and Cr(VI) >15 ppb. Simple mixing lines between the

Genetics Home Reference: glycoprotein VI deficiency

MedlinePlus

... protein called glycoprotein VI (GPVI). This protein is embedded in the outer membrane of blood cell fragments ... erythematosus (SLE). Autoimmune disorders occur when the immune system malfunctions and attacks the body's own cells and ...

Identification of Type VI Collagen Synthesizing Cells in Human Diabetic Glomerulosclerosis Using Renal Biopsy Sections

PubMed Central

Razzaque, Mohammed Shawkat; Koji, Takehiko; Harada, Takashi; Taguchi, Takashi

1997-01-01

Although the role of extracellular matrices in the development of glomerulosclerosis has been discussed widely, the cellular origin of type VI collagen in diabetic nephropathy (DN) has remained relatively unexplored. This study reports the distribution and cellular origin of type VI collagen in DN. Type VI collagen‐specific oligonucleotide probes and monoclonal antibody were used to assess the relative expression of mRNA for \\alpha1 (VI) chain and its translated protein in paraffin‐embedded renal biopsy sections of DN. By immunohistochemistry, compared to the control, increased deposition of type VI collagen was noted in the diffuse and nodular lesions of diabetic glomeruli. For cellular localization of type VI collagen mRNA, paraffin‐embedded renal sections of the control and DN were hybridized in situ with digoxigenin (Dig)‐labeled antisense oligo‐DNA probe complementary to a part of \\alpha1 (VI) mRNA. In comparison to the control kidney sections, increased numbers of intraglomerular cells (both mesangial and epithelial cells) were positive for α1 (VI) mRNA in renal biopsy sections of DN. From the results, we conclude that overexpression of type VI collagen by intraglomerular cells with its increased deposition might significantly contribute to the glomerulosclerosis found in DN. PMID:9497854

Final Technical Report -- GEO-VI - USGEO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirsch, Leonard

2009-11-30

Representatives of US earth observations departments and agencies, other participating governments, NGOs and civil society participated in the Sixth Plenary Meeting of the Group on Earth Observations (GEO-VI), hosted by the United States in Washington, DC on November 17 and 18, 2009. The meeting was held in the Atrium Ballroom of the Ronald Reagan International Trade Center. Exhibitions of international Earth observation technology and programs were held concurrently in the same venue. A number of GEO committee meetings and side events were held in conjunction with the GEO-VI Plenary, including the GEO-IGOS Symposium on Earth observation science and applications, themore » GEOSS in the Americas Forum on Coastal Zones, and separate meetings of the GEO Communities of Practice on Carbon, Health, and Air Quality.« less

Effect of potassium ferrate(VI) on survival and reproduction of Ichthyophthirius multifiliis tomonts.

PubMed

Ling, Fei; Wang, Jian-Guo; Wang, Gao-Xue; Gong, Xiao-Ning

2011-11-01

Ichthyophthirius multifiliis is an important freshwater teleost pathogen that can infect most species of freshwater fish worldwide and often leads to significant economic losses to the aquaculture industry. Potassium ferrate(VI), as a potential therapeutic agent for external protozoan parasite infections, has been proven to kill I. multifiliis theronts effectively; however, no information is available on effects of potassium ferrate(VI) exposure to I. multifiliis tomonts. This study evaluated the effects of potassium ferrate(VI) on the survival and reproduction of I. multifiliis tomonts. The results of experiment 1 showed that potassium ferrate(VI) at concentrations of 2.4, 4.8, 9.6, and 19.2 mg/L resulted in tomont survival rates of 82.2%, 34.2%, 14.6%, and 0, respectively, and significant differences were noted in tomont reproduction between the treatments and the control (P < 0.05). Additionally, this study was designed to determine the effect of potassium ferrate(VI) toxicity on age of the tomont. The results indicated that encysted I. multifiliis was more resistant to potassium ferrate(VI) treatments. In addition, this study was designed to investigate I. multifiliis tomont survival and reproduction when collected from infested goldfish in potassium ferrate(VI) solutions at different concentrations (0, 2.4, 4.8, 9.6, and 19.2 mg/L) for 30 min. It was found that the tomont survivals in the treatments were significantly lower than those in the control (P < 0.05). This study demonstrated that a bath with potassium ferrate(VI) possibly was an effective method to treat ichthyophthiriasis.

Modeling of Cr(VI) Bioreduction Under Fermentative and Denitrifying Conditions

NASA Astrophysics Data System (ADS)

Molins, S.; Steefel, C.; Yang, L.; Beller, H. R.

2011-12-01

The mechanisms of bioreductive immobilization of Cr(VI) were investigated by reactive transport modeling of a set of flow-through column experiments performed using natural Hanford 100H aquifer sediment. The columns were continuously eluted with 5 μM Cr(VI), 5 mM lactate as the electron donor, and selected electron acceptors (tested individually). Here we focus on the two separate experimental conditions that showed the most removal of Cr(VI) from solution: fermentation and denitrification. In each case, a network of enzymatic and abiotic reaction pathways was considered to interpret the rate of chromate reduction. The model included biomass growth and decay, and thermodynamic limitations on reaction rates, and was constrained by effluent concentrations measured by IC and ICP-MS and additional information from bacterial isolates from column effluent. Under denitrifying conditions, Cr(VI) reduction was modeled as co-metabolic with nitrate reduction based on experimental observations and previous studies on a denitrifying bacterium derived from the Hanford 100H aquifer. The reactive transport model results supported this interpretation of the reaction mechanism and were used to quantify the efficiency of the process. The models results also suggest that biomass growth likely relied on a nitrogen source other than ammonium (e.g. nitrate). Under fermentative conditions and based on cell suspension studies performed on a bacterial isolate from the columns, the model assumes that Cr(VI) reduction is carried out directly by fermentative bacteria that convert lactate into acetate and propionate. The evolution to complete lactate fermentation and Cr(VI) reduction took place over a week's time and simulations were used to determine an estimate for a lower limit of the rate of chromate reduction by calibration with the flow-through column experimental results. In spite of sulfate being added to these columns, sulfate reduction proceeded at a slow rate and was not well

Measurement of varus-valgus and internal-external rotational knee laxities in vivo--Part II: relationship with anterior-posterior and general joint laxity in males and females.

PubMed

Shultz, Sandra J; Shimokochi, Yohei; Nguyen, Anh-Dung; Schmitz, Randy J; Beynnon, Bruce D; Perrin, David H

2007-08-01

We examined sex differences in general joint laxity (GJL), and anterior-posterior displacement (ANT-POST), varus-valgus rotation (VR-VL), and internal-external rotation (INT-EXT) knee laxities, and determined whether greater ANT and GJL predicted greater VR-VL and INT-EXT. Twenty subjects were measured for GJL, and scored on a scale of 0-9. ANT and POST were measured using a standard knee arthrometer at 133 N. VR-VL and INT-EXT were measured using a custom joint laxity testing device, defined as the angular displacements (deg) of the tibia relative to the femur produced by 0-10 Nm of varus-valgus torques, and 0-5 Nm of internal-external torques, respectively. INT-EXT were measured during both non-weight-bearing (NWB) and weight-bearing (WB = 40% body weight) conditions while VR-VL were measured NWB. All laxity measures were greater for females compared to males except for POST. ANT and GJL positively predicted 62.5% of the variance in VR-VL and 41.8% of the variance in WB INT-EXT. ANT was the sole predictor of INT-EXT in NWB, explaining 42.3% of the variance. These findings suggest that subjects who score higher on clinical measures of GJL and ANT are also likely to have greater VR-VL and INT-EXT knee laxities.

Hallux Valgus, By Nature or Nurture? A Twin Study.

PubMed

Munteanu, Shannon E; Menz, Hylton B; Wark, John D; Christie, Jemma J; Scurrah, Katrina J; Bui, Minh; Erbas, Bircan; Hopper, John L; Wluka, Anita E

2017-09-01

To evaluate the contributions of shared but unmeasured genetic and environmental factors to hallux valgus (HV). Between 2011 and 2012, 74 monozygotic (MZ) and 56 dizygotic (DZ) female twin pairs self-reported HV and putative risk factors, including footwear use across their lifespan. Estimates of casewise concordance (P C ), correlation (ρ), and odds ratios (ORs) were calculated, adjusting for age and other risk factors, and compared between MZ and DZ pairs using logistic regression, generalized estimating equations, and a maximum likelihood-based method, respectively. A total of 70 participants (27%) reported HV, with 12 MZ and 7 DZ pairs being concordant. After adjusting for age, twins were correlated (ρ = 0.27 [95% confidence interval (95% CI) 0.08, 0.46]) and concordant (P C  = 0.45 [95% CI 0.29, 0.61]; mean age 58 years), with no difference between MZ and DZ pairs (P = 0.7). HV was associated with regularly wearing footwear with a constrictive toe-box during the fourth decade (adjusted OR 2.73 [95% CI 1.12, 6.67]). This risk factor was correlated in MZ (ρ = 0.38 [95% CI 0.15, 0.60]) but not DZ (ρ = -0.20 [95% CI -0.43, 0.03]) pairs. These correlations were significantly different (P = 0.002). Twins are correlated for HV, but we found no evidence that correlation was due to shared genetic factors. We identified an environmental risk factor, footwear with a constrictive toe-box, that is not shared to the same extent by MZ and DZ pairs, contrary to the assumption of the classic twin model. Footwear, and possibly genetic factors and unknown shared environmental factors, could contribute to developing HV. © 2016, American College of Rheumatology.

Remediation of uranium contaminated soils with bicarbonate extraction and microbial U(VI) reduction

USGS Publications Warehouse

Philips , Elizabeth J.P.; Landa, Edward R.; Lovely, Derek R.

1995-01-01

A process for concentrating uranium from contaminated soils in which the uranium is first extracted with bicarbonate and then the extracted uranium is precipitated with U(VI)-reducing microorganisms was evaluated for a variety of uranuum-contaminated soils. Bicarbonate (100 mM) extracted 20–94% of the uranium that was extracted with nitric acid. The U(VI)-reducing microorganism,Desulfovibrio desulfuricans reduced the U(VI) to U(IV) in the bicarbonate extracts. In some instances unidentified dissolved extracted components, presumably organics, gave the extract a yellow color and inhibited U(VI) reduction and/or the precipitation of U(IV). Removal of the dissolved yellow material with the addition of hydrogen peroxide alleviated this inhibition. These results demonstrate that bicarbonate extraction of uranium from soil followed by microbial U(VI) reduction might be an effective mechanism for concentrating uranium from some contaminated soils.

Osteogenesis Imperfecta Type VI in Individuals from Northern Canada.

PubMed

Ward, Leanne; Bardai, Ghalib; Moffatt, Pierre; Al-Jallad, Hadil; Trejo, Pamela; Glorieux, Francis H; Rauch, Frank

2016-06-01

Osteogenesis imperfecta (OI) type VI is a recessively inherited form of OI that is caused by mutations in SERPINF1, the gene coding for pigment-epithelium derived factor (PEDF). Here, we report on two apparently unrelated children with OI type VI who had the same unusual homozygous variant in intron 6 of SERPINF1 (c.787-10C>G). This variant created a novel splice site that led to the in-frame addition of three amino acids to PEDF (p.Lys262_Ile263insLeuSerGln). Western blotting showed that skin fibroblasts with this mutation produced PEDF but failed to secrete it. Both children were treated with intravenous bisphosphonates, but the treatment of Individual 1 was switched to subcutaneous injections of denosumab (dose 1 mg per kg body weight, repeated every 3 months). An iliac bone sample obtained after 5 denosumab injections (and 3 months after the last injection) showed no change in the increased osteoid parameters that are typical of OI type VI, but the number of osteoclasts in trabecular bone was markedly increased. This suggests that the effect of denosumab on osteoclast suppression is of shorter duration in children with OI type VI than what has previously been reported on adults with osteoporosis.

IN SITU CR(VI) TREATMENT USING A FERROUS IRON-BASED REDUCTANT

EPA Science Inventory

Laboratory and field studies were conducted to evaluate the performance of a ferrous sulfate/ sodium hydrosulfite (dithionite) reductant blend in treating a hexavalent chromium (Cr(VI)) source area and Cr(VI) dissolved phase plume at a former industrial site in Charleston, South ...

Flow injection for the determination of Se(IV) and Se(VI) by hydride generation atomic absorption spectrometry with microwave oven on-line prereduction of Se(VI) to Se(IV)

NASA Astrophysics Data System (ADS)

Burguera, J. L.; Carrero, P.; Burguera, M.; Rondon, C.; Brunetto, M. R.; Gallignani, M.

1996-12-01

An on-line flow injection system has been developed for the selective determination of Se(IV) and Se(VI) in citric fruit juices and geothermal waters by hydride generation atomic absorption spectrometry with microwave-aided heating prereduction of Se(VI) to Se(IV). The samples and the prereductant solutions (4 mol l -1 HCl for Se(IV) and 12 mol l -1 HCl for Se(VI)) which circulated in a closed-flow circuit were injected by means of a time-based injector. This mixture was displaced by a carrier solution of 1% v/v of hydrochloric acid through a PTFE coil located inside the focused microwave oven and mixed downstream with a borohydride solution to generate the hydride. The linear ranges were 0-120 and 0-100 μg l -1 of Se(IV) and Se(VI), respectively. The detection limits were 1.0 μg l -1 for Se(IV) and 1.5 μg l -1 for Se(VI). The precision (about 2.0-2.5% RSD) and recoveries (96-98% for Se(IV) and 94-98% for Se(VI)) were good. Total selenium values were also obtained by electrothermal atomic absorption spectrometry which agreed with the content of both selenium species. The sample throughput was about 50 measurements per hour. The main advantage of the method is that the selective determination of Se(IV) and Se(VI) in citric fruit juices and geothermal waters is performed in a closed system with a minimum sample manipulation, exposure to the environment, minimum sample waste and operator attention.

Box-Behnken experimental design for chromium(VI) ions removal by bacterial cellulose-magnetite composites.

PubMed

Stoica-Guzun, Anicuta; Stroescu, Marta; Jinga, Sorin Ion; Mihalache, Nicoleta; Botez, Adriana; Matei, Cristian; Berger, Daniela; Damian, Celina Maria; Ionita, Valentin

2016-10-01

In this study bacterial cellulose-magnetite composites were synthesised for the removal of chromium(VI) from aqueous solutions. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the bacterial cellulose-magnetite composites and to reveal the uniform dispersion of nanomagnetite in the BC matrix. Magnetic properties were also measured to confirm the magnetite immobilization on bacterial cellulose membrane. The effects of initial Cr(VI) concentration, solution pH and solid/liquid ratio upon chromium removal were examined using the statistical Box-Behnken Design. Because of the possibility of magnetite dissolution during chromium(VI) adsorption, the degree of iron leaching was also analysed in the same conditions as Cr(VI) adsorption. From the factors affecting chromium(VI) adsorption the most important was solution pH. The highest Cr(VI) removal efficiency was observed at pH 4, accompanied by the lowest iron leaching in the solution. The adsorption experiments also indicated that the adsorption process of chromium(VI) is well described by Freundlich adsorption model. Our results proved that the BC-magnetite composites could be used for an efficient removal of chromium(VI) from diluted solutions with a minimum magnetite dissolution during operation. Copyright © 2016 Elsevier B.V. All rights reserved.

Bacterial Cr(VI) reduction concurrently improves sunflower (Helianthus Annuus L.) growth.

PubMed

Faisal, Muhammad; Hasnain, Shahida

2005-07-01

Four Cr(VI)-reducing bacterial strains (Ochrobactrum intermedium, CrT-2, CrT-3 and CrT-4) previously isolated from chromium-contaminated sites were inoculated on to seeds of sunflower (Helianthus annuus var SF-187), which were germinated and grown along with non-inoculated controls with chromate salts (300 microg CrCl3 or K2CrO4 ml(-1)). Severe reduction (20%) in seed germination was observed in Cr(VI) stress. Plant height decreased (36%) with Cr(VI) when compared with chromium-free control, while O. intermedium inoculation resulted a 20% increment in this parameter as compared to non-inoculated chromium-free control. CrT-3 inoculation resulted a 69% increment in auxin content as compared to non-inoculated control. O. intermedium caused 30% decrease in chromium uptake in sunflower plant roots under Cr(VI) stress as compared to chromium-free control plants.

Reaction kinetics and oxidation products formation in the degradation of ciprofloxacin and ibuprofen by ferrate(VI).

PubMed

Zhou, Zhengwei; Jiang, Jia-Qian

2015-01-01

The treatment of ciprofloxacin (CIP) and ibuprofen (IBU) in test solutions by ferrate(VI) was investigated in this study. A series of jar test was performed in bench-scale at pH 6-9 and ferrate(VI) dose of 1-5 mg L(-1). Results demonstrated that ferrate(VI) removed CIP from test solutions efficiently, with above 70% of reduction under study conditions. In contrary, the removal rates of IBU were very low, less than 25% in all conditions. Raising ferrate(VI) dose improved the treatment performance, while the influence of solution pH was not significant at pH 6-9 compared with that of ferrate(VI) dose. In addition, kinetic studies of ferrate(VI) with both compounds were carried out at pH 8 and pH 9 (20 °C). Ferrate(VI) had a much higher reactivity with CIP than IBU at pH 8 and pH 9, with CIP's apparent second-order rate constants of 113.7±6.3 M(-1) s(-1) and 64.1±1.0 M(-1) s(-1), respectively. The rate constants of ferrate(VI) with IBU were less than 0.2 M(-1) s(-1) at pH 8 and pH 9. Furthermore, seven oxidation products (OPs) were formed during CIP degradation by ferrate(VI). The attack on the piperazinyl ring of the CIP by ferrate(VI) appeared to lead to the cleavage or hydroxylation of the rings, and the attack on the quinolone moiety by ferrate(VI) might lead to the cleavage of the double bond at the six-member heterocyclic ring. No OPs of IBU were detected during ferrate(VI) oxidation due to very small part of IBU was degraded by ferrate(VI). Copyright © 2014 Elsevier Ltd. All rights reserved.

Title VI: 1995-96 Final Report. Publication No. 95.11.

ERIC Educational Resources Information Center

Griffith, Julia E.

Title VI provide Federal funds to states through the Elementary and Secondary Education Act of 1965 as amended in 1994. Title VI funds can support one or more programs that include school reform activities, the purchase and use of instructional and educational materials, programs for the gifted and talented, and programs of various sorts for the…

Preparation and Cr(VI) removal performance of corncob activated carbon.

PubMed

Li, Hongyan; Gao, Pei; Cui, Jianguo; Zhang, Feng; Wang, Fang; Cheng, Jici

2018-05-12

Corncob activated carbon (CCAC) was prepared by a H 3 PO 4 activation method. The optimum conditions for the preparation of CCAC were determined by orthogonal experiments. The effects of pH, reaction time, CCAC dosage, and hexavalent chromium (Cr(VI)) concentrations on Cr(VI) removal by CCAC were studied. Corn straw activated carbon (CSAC) was also prepared using the optimum preparation conditions determined for CCAC. The properties of samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analysis, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The results showed that the optimum preparation conditions for CCAC were as follows: a mass of corncob of 10 g; a mass ratio of corncob to H 3 PO 4 of 1:2; a 5% H 3 BO 3 content of 10 mL; an impregnation time of 45 min; a carbonization temperature of 500 °C. The optimum conditions for the removal of Cr(VI) were as follows: pH < 9; temperature, 308 K; rotation speed, 150 r min -1 ; reaction time, 60 min; CCAC dosage, 1 g L -1 . The Cr(VI) removal rate was above 98%, and the maximum adsorption capacity of CCAC was 9.985 mg g -1 . The concentration of residual Cr(VI) in water was less than 0.05 mg L -1 . FTIR showed that the surfaces of the samples had more oxygen-containing functional groups, which promoted the adsorption. XRD showed that CCAC and CSAC had similar peaks and that these peaks promoted the adsorption of Cr(VI). BET indicated that the number of pores in the samples followed the order CCAC > CSAC > CAC. SEM showed that the CCAC surface had a more porous structure, which enhanced adsorption. EDS showed that the C contents of CCAC and CSAC were much higher than that of CAC. Cr(VI) adsorption on CCAC followed quasi-second-order kinetics and was in accordance with a Langmuir adsorption isotherm, with monolayer adsorption. The adsorption reaction was endothermic, where higher

Papaya Seeds as A Low-Cost Sorbent for Removing Cr(VI) from The Aqueous Solution

NASA Astrophysics Data System (ADS)

Rahmawati, Atik; Marwoto, Putut; Karunia Z, Anita

2016-08-01

The presence of chromium (VI) contaminants and their toxicity in aqueous streams important environmental problems. Adsorption is one of the effective techniques that can be used for removing metal from wastewater. This research was initiated by preparing sorbent from papaya seeds and determining its functional group contents by using FT-IR. The adsorption process was carried out in a batch method. The study of adsorption aspects involved the pH, initial Cr (VI) concentration and contact time between Cr (VI) and sorbent. FT IR analysis results showed that the main functional groups are carbonyl, hydroxyl, and carboxylic. It was also found that the effective pH for Cr (VI) uptake is 2.0 and increasing contact time would increase the Cr (VI) uptake. In addition, the equilibrium was reached after 40 minutes interaction and the increase of initial chromium (VI) concentration would increase the sorbent uptake percentage. All these results indicated that papaya seed is a potential sorbent for removing Cr (VI) from aqueous solutions.

Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments

USGS Publications Warehouse

Yin, J.; Haggerty, R.; Stoliker, D.L.; Kent, D.B.; Istok, J.D.; Greskowiak, J.; Zachara, J.M.

2011-01-01

In the 300 Area of a U(VI)-contaminated aquifer at Hanford, Washington, USA, inorganic carbon and major cations, which have large impacts on U(VI) transport, change on an hourly and seasonal basis near the Columbia River. Batch and column experiments were conducted to investigate the factors controlling U(VI) adsorption/desorption by changing chemical conditions over time. Low alkalinity and low Ca concentrations (Columbia River water) enhanced adsorption and reduced aqueous concentrations. Conversely, high alkalinity and high Ca concentrations (Hanford groundwater) reduced adsorption and increased aqueous concentrations of U(VI). An equilibrium surface complexation model calibrated using laboratory batch experiments accounted for the decrease in U(VI) adsorption observed with increasing (bi)carbonate concentrations and other aqueous chemical conditions. In the column experiment, alternating pulses of river and groundwater caused swings in aqueous U(VI) concentration. A multispecies multirate surface complexation reactive transport model simulated most of the major U(VI) changes in two column experiments. The modeling results also indicated that U(VI) transport in the studied sediment could be simulated by using a single kinetic rate without loss of accuracy in the simulations. Moreover, the capability of the model to predict U(VI) transport in Hanford groundwater under transient chemical conditions depends significantly on the knowledge of real-time change of local groundwater chemistry. Copyright 2011 by the American Geophysical Union.

Transient groundwater chemistry near a river: Effects on U(VI) transport in laboratory column experiments

USGS Publications Warehouse

Yin, Jun; Haggerty, Roy; Stoliker, Deborah L.; Kent, Douglas B.; Istok, Jonathan D.; Greskowiak, Janek; Zachara, John M.

2011-01-01

In the 300 Area of a U(VI)-contaminated aquifer at Hanford, Washington, USA, inorganic carbon and major cations, which have large impacts on U(VI) transport, change on an hourly and seasonal basis near the Columbia River. Batch and column experiments were conducted to investigate the factors controlling U(VI) adsorption/desorption by changing chemical conditions over time. Low alkalinity and low Ca concentrations (Columbia River water) enhanced adsorption and reduced aqueous concentrations. Conversely, high alkalinity and high Ca concentrations (Hanford groundwater) reduced adsorption and increased aqueous concentrations of U(VI). An equilibrium surface complexation model calibrated using laboratory batch experiments accounted for the decrease in U(VI) adsorption observed with increasing (bi)carbonate concentrations and other aqueous chemical conditions. In the column experiment, alternating pulses of river and groundwater caused swings in aqueous U(VI) concentration. A multispecies multirate surface complexation reactive transport model simulated most of the major U(VI) changes in two column experiments. The modeling results also indicated that U(VI) transport in the studied sediment could be simulated by using a single kinetic rate without loss of accuracy in the simulations. Moreover, the capability of the model to predict U(VI) transport in Hanford groundwater under transient chemical conditions depends significantly on the knowledge of real-time change of local groundwater chemistry.

Validation of the Preverbal Visual Assessment (PreViAs) questionnaire.

PubMed

García-Ormaechea, Inés; González, Inmaculada; Duplá, María; Andres, Eva; Pueyo, Victoria

2014-10-01

Visual cognitive integrative functions need to be evaluated by a behavioral assessment, which requires an experienced evaluator. The Preverbal Visual Assessment (PreViAs) questionnaire was designed to evaluate these functions, both in general pediatric population or in children with high risk of visual cognitive problems, through primary caregivers' answers. We aimed to validate the PreViAs questionnaire by comparing caregiver reports with results from a comprehensive clinical protocol. A total of 220 infants (<2 years old) were divided into two groups according to visual development, as determined by the clinical protocol. Their primary caregivers completed the PreViAs questionnaire, which consists of 30 questions related to one or more visual domains: visual attention, visual communication, visual-motor coordination, and visual processing. Questionnaire answers were compared with results of behavioral assessments performed by three pediatric ophthalmologists. Results of the clinical protocol classified 128 infants as having normal visual maturation, and 92 as having abnormal visual maturation. The specificity of PreViAs questionnaire was >80%, and sensitivity was 64%-79%. More than 80% of the infants were correctly classified, and test-retest reliability exceeded 0.9 for all domains. The PreViAs questionnaire is useful to detect abnormal visual maturation in infants from birth to 24months of age. It improves the anamnesis process in infants at risk of visual dysfunctions. Copyright © 2014. Published by Elsevier Ireland Ltd.

Chromium (VI) biosorption by Saccharomyces cerevisiae subjected to chemical and thermal treatments.

PubMed

De Rossi, Andrea; Rigon, Magali Rejane; Zaparoli, Munise; Braido, Rafael Dalmas; Colla, Luciane Maria; Dotto, Guilherme Luiz; Piccin, Jeferson Steffanello

2018-05-28

The potential of chemically and thermally treated Saccharomyces cerevisiae as biosorbents for chromium (VI) was investigated in this work. The presence of this toxic metal in industrial effluents is harmful to the environment, so, it is important to develop environmental friendly methods for Cr(VI) removal from these effluents. Biosorption using microorganisms such as S. cerevisiae is a viable treatment option because this biomass is easily available as a residue of fermentation industries. In this study, the affecting variables on Cr(VI) biosorption were studied by constructing biosorption isotherms, using lyophilized yeast subjected to chemical and thermal treatments. S. cerevisiae was able to remove 99.66% of Cr(VI) from effluents by biosorption. The significant variables affecting biosorption were pH, initial Cr(VI) concentration, and contact time. The biosorption isotherms were represented by the Freundlich model for the untreated biomass, BET model for the chemically treated biomass, and Langmuir model for the heat-treated biomass. Thermal treatment increased the biosorption affinity of the biomass for chromium, while the chemical treatment facilitated the formation of a multilayer.

Influence of calcite and dissolved calcium on uranium(VI) sorption to a hanford subsurface sediment.

PubMed

Dong, Wenming; Ball, William P; Liu, Chongxuan; Wang, Zheming; Stone, Alan T; Bai, Jing; Zachara, John M

2005-10-15

The influence of calcite and dissolved calcium on U(VI) adsorption was investigated using a calcite-containing sandy silt/clay sediment from the U. S. Department of Energy Hanford site. U(VI) adsorption to sediment, treated sediment, and sediment size fractions was studied in solutions that both had and had not been preequilibrated with calcite, at initial [U(VI)] = 10(-7)-10(-5) mol/L and final pH = 6.0-10.0. Kinetic and reversibility studies (pH 8.4) showed rapid sorption (30 min), with reasonable reversibility in the 3-day reaction time. Sorption from solutions equilibrated with calcite showed maximum U(VI) adsorption at pH 8.4 +/- 0.1. In contrast, calcium-free systems showed the greatest adsorption at pH 6.0-7.2. At pH > 8.4, U(VI) adsorption was identical from calcium-free and calcium-containing solutions. For calcite-presaturated systems, both speciation calculations and laser-induced fluorescence spectroscopic analyses indicated that aqueous U(VI) was increasingly dominated by Ca2UO2(CO3)3(0)(aq) at pH < 8.4 and thatformation of Ca2UO2(CO3)3(0)(aq) is what suppresses U(VI) adsorption. Above pH 8.4, aqueous U(VI) speciation was dominated by UO2(CO3)3(4-) in all solutions. Finally, results also showed that U(VI) adsorption was additive in regard to size fraction but not in regard to mineral mass: Carbonate minerals may have blocked U(VI) access to surfaces of higher sorption affinity.

Cathodic reduction of hexavalent chromium [Cr(VI)] coupled with electricity generation in microbial fuel cells.

PubMed

Wang, Gang; Huang, Liping; Zhang, Yifeng

2008-11-01

A novel approach to Cr(VI)-contaminated wastewater treatment was investigated using microbial fuel cell technologies in fed-batch mode. By using synthetic Cr(VI)-containing wastewater as catholyte and anaerobic microorganisms as anodic biocatalyst, Cr(VI) at 100 mg/l was completely removed during 150 h (initial pH 2). The maximum power density of 150 mW/m(2) (0.04 mA/cm(2)) and the maximum open circuit voltage of 0.91 V were generated with Cr(VI) at 200 mg/l as electron acceptor. This work verifies the possibility of simultaneous electricity production and cathodic Cr(VI) reduction.

Molecular characterization and phylogenetic analysis of Citrus viroid VI variants from citrus in China

USDA-ARS?s Scientific Manuscript database

Citrus viroid VI (CVd-VI) was originally found from citrus and persimmon in Japan. We report here the identification and molecular characterization of CVd-VI from four production regions of China. A total of 90 cDNA clones from nine infected citrus cultivars were sequenced. The sequence homologies o...

Method of manufacturing semiconductor having group II-group VI compounds doped with nitrogen

DOEpatents

Compaan, Alvin D.; Price, Kent J.; Ma, Xianda; Makhratchev, Konstantin

2005-02-08

A method of making a semiconductor comprises depositing a group II-group VI compound onto a substrate in the presence of nitrogen using sputtering to produce a nitrogen-doped semiconductor. This method can be used for making a photovoltaic cell using sputtering to apply a back contact layer of group II-group VI compound to a substrate in the presence of nitrogen, the back coating layer being doped with nitrogen. A semiconductor comprising a group II-group VI compound doped with nitrogen, and a photovoltaic cell comprising a substrate on which is deposited a layer of a group II-group VI compound doped with nitrogen, are also included.

Catalytic effect of soil colloids on the reaction between CrVI and p-methoxyphenol.

PubMed

Zhou, D M; Chen, H M; Zheng, C R; Tu, C

2001-01-01

Adsorption of CrVI and p-methoxyphenol (PMP) on soil colloids at different pH media was studied. The resulting k1 and n of 1.89 x 10(2) and 0.53 (r2 = 0.99) and k2 and b of 0.13 and 1.25 x 10(3) (r2 = 0.96) were obtained from Freundlich (Q = k1Caqn) and Langmuir [Q = k2bCaq/(1 + k2Caq)] simulation equations, respectively, for CrVI adsorption on soil colloids (pH 4.20). The adsorption of PMP on soil colloids in pH 5.72 media was simulated by five different equations and the results indicated that the Fritz-Schluender one (r2 = 1.00) was the most suitable among them. Adsorption quantity of CrVI and PMP on colloids increased with increasing acidity in the pH range of 3.5-9.0. Study of CrVI adsorption kinetics indicated that the adsorption equilibrium of CrVI was reached rapidly within 2 h. In pure aqueous solution, CrVI reduction by PMP was observed only when the media's pH was lower than 4.0. Oxidation and reduction reaction between CrVI and p-methoxyphenol obviously occurred when soil colloids were involved in this system, even at pH > or = 7.0, which strongly suggested that minerals in soil colloids acted as catalysts to speed the reaction of CrVI and PMP. The oxidized product of PMP by CrVI, extracted by chloroform in acid media and analyzed by gas chromatography-mass spectrometry, was identified as benzoquinone. The reaction included two steps of one electron process.

Biodegradable magnesium-based screw clinically equivalent to titanium screw in hallux valgus surgery: short term results of the first prospective, randomized, controlled clinical pilot study

PubMed Central

2013-01-01

Purpose Nondegradable steel-and titanium-based implants are commonly used in orthopedic surgery. Although they provide maximal stability, they are also associated with interference on imaging modalities, may induce stress shielding, and additional explantation procedures may be necessary. Alternatively, degradable polymer implants are mechanically weaker and induce foreign body reactions. Degradable magnesium-based stents are currently being investigated in clinical trials for use in cardiovascular medicine. The magnesium alloy MgYREZr demonstrates good biocompatibility and osteoconductive properties. The aim of this prospective, randomized, clinical pilot trial was to determine if magnesium-based MgYREZr screws are equivalent to standard titanium screws for fixation during chevron osteotomy in patients with a mild hallux valgus. Methods Patients (n=26) were randomly assigned to undergo osteosynthesis using either titanium or degradable magnesium-based implants of the same design. The 6 month follow-up period included clinical, laboratory, and radiographic assessments. Results No significant differences were found in terms of the American Orthopaedic Foot and Ankle Society (AOFAS) score for hallux, visual analog scale for pain assessment, or range of motion (ROM) of the first metatarsophalangeal joint (MTPJ). No foreign body reactions, osteolysis, or systemic inflammatory reactions were detected. The groups were not significantly different in terms of radiographic or laboratory results. Conclusion The radiographic and clinical results of this prospective controlled study demonstrate that degradable magnesium-based screws are equivalent to titanium screws for the treatment of mild hallux valgus deformities. PMID:23819489

Genetics Home Reference: mucopolysaccharidosis type VI

MedlinePlus

... Citation on PubMed Garrido E, Cormand B, Hopwood JJ, Chabás A, Grinberg D, Vilageliu L. Maroteaux-Lamy ... N, Leão Teles E, Sá Miranda MC, Hopwood JJ. Mutational analysis of 105 mucopolysaccharidosis type VI patients. ...

Cr(VI) adsorption from electroplating plating wastewater by chemically modified coir pith.

PubMed

Suksabye, Parinda; Thiravetyan, Paitip

2012-07-15

Coir pith samples were chemically modified by grafting with acrylic acid for the removal of Cr(VI) from electroplating wastewater. The presence of acrylic acid on the coir pith surface was verified by a scanning electron microscope with an electron dispersive x-ray spectrometer (SEM/EDX), Fourier transform infrared spectroscopy (FTIR) and thermogravimetry (TG). The carbonyl groups (C==O) from the carboxylic acids (COOH) increased on the coir pith surface after grafting with acrylic acid. In addition, the thermal stability of the acrylic acid-grafted coir pith also improved. The optimum conditions for grafting the acrylic acid on the coir pith consisted of 2 M acrylic acid and 0.00125 M ceric ammonium nitrate (CAN, as an initiator). The maximum Cr(VI) removal (99.99 ± 0.07%) was obtained with the following conditions: a 1.3% (w/v) dosage of acrylic acid-grafted coir pith, a system pH of 2, a contact time of 22 h, a temperature of 30 °C, a particle size of <150 μm and an initial Cr(VI) of 1,171 mg l(-1). At system pH of 2, Cr(VI) in the HCrO(4)(-) form can be adsorbed with acrylic acid-grafted coir pith via an electrostatic attraction. The adsorption isotherm of 2 M acrylic acid-grafted coir pith exhibited a good fit with the Langmuir isotherm. The maximum Cr(VI) adsorption capacity of the 2 M acrylic acid-grafted coir pith was 196.00 mg Cr(VI) g(-1) adsorbent, whereas for coir pith without grafting, the maximum Cr(VI) removal was 165.00 mg Cr(VI) g(-1) adsorbent. The adsorption capacity of the acrylic acid-grafted coir pith for Cr(VI) was higher compared to the original coir pith. This result was due to the enhancement of the carbonyl groups on the coir pith surface that may have involved the mechanism of chromium adsorption. The X-ray absorption near edged structure (XANES) and desorption studies suggested that most of the Cr(III) that presented on the acrylic acid-grafted coir pith was due to the Cr(VI) being reduced to Cr(III) on the adsorbent surface. FTIR

Study on Adsorption of Chromium (VI) by Activated Carbon from Cassava Sludge

NASA Astrophysics Data System (ADS)

Yang, Jinhui; Li, Chuanshu; Yang, Bin; Kang, Sijun; Zhang, Zhen

2018-03-01

In this paper, a new type of adsorbent prepared by waste sludge from alcohol production industry was used to adsorb Cr (VI) in activated carbon from cassava sludge. A series of static adsorption experiments were carried out on the initial concentration of solution Cr (VI), pH value of solution, adsorption time and dosage of adsorbent. The results of single factor experiments show that the removal rate of Cr (VI) increases with the initial concentration of Cr(VI), while the adsorption amount is opposite. When the pH value of the solution is low, the adsorption effect of activated carbon is better.The adsorption time should be controlled within 40-60min. When the activated carbon dosage is increased, the removal rate increases but the adsorption capacity decreases.

Efficacy trial of Vi polysaccharide vaccine against typhoid fever in south-western China.

PubMed Central

Yang, H. H.; Wu, C. G.; Xie, G. Z.; Gu, Q. W.; Wang, B. R.; Wang, L. Y.; Wang, H. F.; Ding, Z. S.; Yang, Y.; Tan, W. S.; Wang, W. Y.; Wang, X. C.; Qin, M.; Wang, J. H.; Tang, H. A.; Jiang, X. M.; Li, Y. H.; Wang, M. L.; Zhang, S. L.; Li, G. L.

2001-01-01

OBJECTIVE: To test the efficacy of locally produced Vi vaccine over a time period of longer than one year. METHODS: A double-blinded, randomized field trial was performed in Guangxi Zhuang Autonomous Region in south-western China, using 30 micrograms doses of locally produced Vi. Enrolled subjects were 3-50 years of age, although the majority (92%) were school-aged children, who have the highest rate of typhoid fever in this setting. A total of 131,271 people were systematically allocated a single dose of 30 micrograms of Vi polysaccharide or saline placebo. The study population was followed for 19 months, with passive surveillance conducted in the Ministry of Health and the Regional Health and Anti-epidemic Centre (HAEC). Clinically suspected cases of typhoid fever were confirmed by blood culture, or by serological reaction with O-antigen (Widal tests). FINDINGS: After 19 months, there were 23 culture-confirmed cases of typhoid fever in the placebo group versus 7 cases in the Vi group (Protective efficacy (PE) = 69%; 95% CI = 28%, 87%). Most of the isolates were from school-aged children: 22 cases in the placebo group versus 6 in the Vi group (PE = 72%; 95% CI = 32%, 82%). No serious post-injection reactions were observed. The locally produced Vi polysaccharide vaccine showed levels of protective efficacy similar to those for Vi vaccine produced in industrial countries. CONCLUSION: The slightly higher dose of vaccine did not seem to alter efficacy significantly in China. PMID:11477965

Determination of chromium (VI) in primary and secondary fertilizer and their respective precursors.

PubMed

Krüger, Oliver; Fiedler, Francesca; Adam, Christian; Vogel, Christian; Senz, Rainer

2017-09-01

Hexavalent chromium species (Cr(VI)) are often carcinogenic, of high acute toxicity, highly mobile, and thus pose a severe risk to health and environment. Fertilizers usually contain significant amounts of chromium. Therefore, a reliable analysis of chromium and the fraction of Cr(VI) are crucial for safe use of fertilizers. This problem is expected to increase in the future, since more and more recycled fertilizers emerge due to increasing fertilizer demand and respective supply risks. However, existing analytical methods have been developed for conventional fertilizers and have to be tested whether they are suitable for the new materials. Thus, we performed a wet-chemical extraction for Cr(VI) on several matrices as well as respective quality control experiments including spiking with Cr(III) and Cr(VI) compounds. We found the Cr(VI) amounts to be below 2 mg/kg except for a thermally post-treated sewage sludge ash (SSA) that showed 12.3 mg/kg. The presence of organic matter e.g. in sludge or precipitated struvite caused a reduction of spiked Cr(VI) and thus no satisfying recovery for quality control. Cr(VI) reduction was also observed for SSA, presumably due to the presence of Fe(II) compounds. Even though the tested procedure can be hampered in some recycled fertilizer matrices, it might be adapted to be applicable also for these complex samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of calcium on aqueous uranium(VI) speciation and adsorption to ferrihydrite and quartz

USGS Publications Warehouse

Fox, P.M.; Davis, J.A.; Zachara, J.M.

2006-01-01

Recent studies of uranium(VI) geochemistry have focused on the potentially important role of the aqueous species, CaUO2 (CO3)32- and Ca2 UO2(CO3)30(aq), on inhibition of microbial reduction and uranium(VI) aqueous speciation in contaminated groundwater. However, to our knowledge, there have been no direct studies of the effects of these species on U(VI) adsorption by mineral phases. The sorption of U(VI) on quartz and ferrihydrite was investigated in NaNO3 solutions equilibrated with either ambient air (430 ppm CO2) or 2% CO2 in the presence of 0, 1.8, or 8.9 mM Ca2+. Under conditions where the Ca2UO2(CO3)30 (aq) species predominates U(VI) aqueous speciation, the presence of Ca in solution lowered U(VI) adsorption on quartz from 77% in the absence of Ca to 42% and 10% at Ca concentrations of 1.8 and 8.9 mM, respectively. U(VI) adsorption to ferrihydrite decreased from 83% in the absence of Ca to 57% in the presence of 1.8 mM Ca. Surface complexation model predictions that included the formation constant for aqueous Ca2UO2(CO3)30(aq) accurately simulated the effect of Ca2+ on U(VI) sorption onto quartz and ferrihydrite within the thermodynamic uncertainty of the stability constant value. This study confirms that Ca2+ can have a significant impact on the aqueous speciation of U(VI), and consequently, on the sorption and mobility of U(VI) in aquifers. ?? 2005 Elsevier Inc. All rights reserved.

On the mechanism of Cr (VI)-induced carcinogenesis: dose dependence of uptake and cellular responses.

PubMed

Liu, K; Husler, J; Ye, J; Leonard, S S; Cutler, D; Chen, F; Wang, S; Zhang, Z; Ding, M; Wang, L; Shi, X

2001-06-01

Cr (VI) compounds are widely used industrial chemicals and are recognized human carcinogens. The mechanisms of carcinogenesis associated with these compounds remain to be investigated. The present study focused on dose-dependence of Cr (VI)-induced uptake and cellular responses. The results show that Cr (VI) is able to enter the cells (human lung epithelial cell line A549) at low concentration (< 10 microM) and that the Cr (VI) uptake appears to be a combination of saturable transport and passive diffusion. Electron spin resonance (ESR) trapping measurements showed that upon stimulation with Cr (VI), A549 cells were able to generate reactive oxygen species (ROS). The amount of ROS generated depended on the Cr (VI) concentration. ROS generation involved NADPH-dependent flavoenzymes. Cr (VI) affected the following cellular parameters in a dose-dependent manner, (a) activation of nuclear transcription factors NF-kappaB, and p53, (b) DNA damage, (c) induction of cell apoptosis, and (d) inhibition of cell proliferation. The activation of transcription factors was assessed by electrophoretic mobility shift assay and western blot analysis, DNA damage by single cell gel electrophoresis assay, cell apoptosis by DNA fragmentation assay, and cell proliferation by a non-radioactive ELISA kit. At the concentration range used in the present study, no thresholds were found in all of these cell responses to Cr (VI). The results may guide further research to better understand and evaluate the risk of Cr (VI)-induced carcinogenesis at low levels of exposure.

Study of Cr(VI) adsorption onto magnetite nanoparticles using synchrotron-based X-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Chen, Yen-Hua; Liu, Dian-Yu; Lee, Jyh-Fu

2018-04-01

In this study, the efficiency of Cr(VI) adsorption onto nano-magnetite was examined by batch experiments, and the Cr(VI) adsorption mechanism was investigated using synchrotron-based X-ray absorption spectroscopy. Magnetite nanoparticles with a mean diameter of 10 nm were synthesized using an inexpensive and simple co-precipitation method. It shows a saturation magnetization of 54.3 emu/g, which can be recovered with an external magnetic field. The adsorption data fitted the Langmuir adsorption isotherm well, implying a monolayer adsorption behavior of Cr(VI) onto nano-magnetite. X-ray absorption spectroscopy results indicate that the adsorption mechanism involves electron transfer between Fe(II) in nano-magnetite (Fe2+OFe3+ 2O3) and Cr(VI) to transform into Cr(III), which may exist as an Fe(III)-Cr(III) mixed solid phase. Moreover, the Cr(III)/Cr(VI) ratio in the final products can be determined by the characteristic pre-edge peak area of Cr(VI) in the Cr K-edge spectrum. These findings suggest that nano-magnetite is effective for Cr(VI) removal from wastewater because it can transform highly poisonous Cr(VI) species into nontoxic Cr(III) compounds, which are highly insoluble and immobile under environmental conditions.

15 CFR Appendix Vi to Subpart P of... - Special-Use Areas Boundary Coordinates and Use Designations

Code of Federal Regulations, 2012 CFR

2012-01-01

... 15 Commerce and Foreign Trade 3 2012-01-01 2012-01-01 false Special-Use Areas Boundary Coordinates and Use Designations VI Appendix VI to Subpart P of Part 922 Commerce and Foreign Trade Regulations... Florida Keys National Marine Sanctuary Pt. 922, Subpt. P, App. VI Appendix VI to Subpart P of Part 922...

15 CFR Appendix Vi to Subpart P of... - Special-Use Areas Boundary Coordinates and Use Designations

Code of Federal Regulations, 2013 CFR

2013-01-01

... 15 Commerce and Foreign Trade 3 2013-01-01 2013-01-01 false Special-Use Areas Boundary Coordinates and Use Designations VI Appendix VI to Subpart P of Part 922 Commerce and Foreign Trade Regulations... Florida Keys National Marine Sanctuary Pt. 922, Subpt. P, App. VI Appendix VI to Subpart P of Part 922...

15 CFR Appendix Vi to Subpart P of... - Special-Use Areas Boundary Coordinates and Use Designations

Code of Federal Regulations, 2014 CFR

2014-01-01

... 15 Commerce and Foreign Trade 3 2014-01-01 2014-01-01 false Special-Use Areas Boundary Coordinates and Use Designations VI Appendix VI to Subpart P of Part 922 Commerce and Foreign Trade Regulations... Florida Keys National Marine Sanctuary Pt. 922, Subpt. P, App. VI Appendix VI to Subpart P of Part 922...

Reduction and removal of Cr(VI) from aqueous solutions using modified byproducts of beer production.

PubMed

Cui, Haojie; Fu, Minglai; Yu, Shen; Wang, Ming Kuang

2011-02-28

Biosorption, as an effective and low-cost technology treating industrial wastewaters containing Cr(VI), has become a significant concern worldwide. In this work, acid-modified byproducts of beer production (BBP) were used to remove Cr(VI) from aqueous solutions. Removal of Cr(VI) increases as the pH is decreased from 4.0 to 1.5, but the maximum of total Cr removal is obtained in a pH range from 2.0 to 2.5. Nearly 60% of the initial Cr(VI) (100 mg L(-1)) was adsorbed or reduced to Cr(III) within the first 10 min at pH 2.0. The Cr(VI) removal capability of acid-modified BBP materials was almost completely retained after regenerating with acid. FT-IR and XPS spectra revealed that carboxylate and carboxyl groups on the surface of modified BBP materials play a major role in Cr(VI) binding and reduction, whereas amide and other groups play a minor role in the Cr(VI) removal process. Copyright © 2010 Elsevier B.V. All rights reserved.

Adsorption isotherm studies of chromium (VI) from aqueous solutions using sol-gel hydrotalcite-like compounds.

PubMed

Ramos-Ramírez, Esthela; Ortega, Norma L Gutiérrez; Soto, Cesar A Contreras; Gutiérrez, Maria T Olguín

2009-12-30

In under-developed countries, industries such as paint and pigment manufacturing, leather tanning, chrome plating and textile processing, usually discharge effluents containing Cr(VI) and Cr(III) into municipal sanitary sewers. It has been reported that Cr(VI) acts as a powerful epithelial irritant and as a human carcinogen. In the present work, hydrotalcite-like compounds with a Mg/Al ratio=2 were synthesized by the sol-gel method. The hydrotalcite-like compounds and their corresponding thermally treated products were characterized by powder X-ray diffraction, infrared spectroscopy and N(2) adsorption. The hydrotalcite-like compounds and the heated solids were used as adsorbents for Cr(VI) in aqueous solutions. Adsorption isotherm studies of Cr(VI) from aqueous solution are described. The adsorbent capacity was determined using the Langmuir, Freundlich and Dubinin-Radushkevich adsorption isotherm models. The Cr(VI) adsorption isotherm data fit best to the Langmuir isotherm model. The maximum Cr(VI) uptake by hydrotalcite and the heated solids was determined using the Langmuir equation and was found to range between 26 and 29 mg Cr(VI)/g adsorbent.

Comparison of the proximal chevron and Ludloff osteotomies for the correction of hallux valgus.

PubMed

Choi, Woo Jin; Yoon, Han Kook; Yoon, Hang Seob; Kim, Bom Soo; Lee, Jin Woo

2009-12-01

Although several studies have described good results of proximal chevron and Ludloff osteotomies, there have been no studies comparing the results of these two techniques at a single institution. We consecutively evaluated 46 patients who underwent proximal chevron osteotomies and 52 patients who underwent Ludloff osteotomies. Patients were evaluated by preoperative and postoperative weight bearing radiographs and the American Orthopaedic Foot and Ankle Society (AOFAS) hallux MP score. Both groups had similarly high AOFAS scores and good correction by radiographic parameters. No statistically significant differences were found with respect to correction of hallux valgus angle (HVA) and intermetatarsal angle (IMA) between the two groups. Significant shortening of the first metatarsal was found after Ludloff osteotomy (p < 0.05). At 6 weeks after surgery, the pain subscore was significantly lower in the proximal chevron group than in the Ludloff group (p < 0.05). The proximal chevron and Ludloff osteotomies yielded equivalent clinical and radiological results. The Ludloff osteotomy with lag screw fixation is more stable and does not require postoperative hardware removal, although it is technically demanding and has a tendency toward greater shortening of the first metatarsal.

Being overweight has limited effect on SCARF osteotomy outcome for hallux valgus correction.

PubMed

Milczarek, Marcin A; Milczarek, Julia J; Tomasik, Bartłomiej; Łaganowski, Przemysław; Nowak, Krzysztof; Domżalski, Marcin

2017-04-01

The purpose of this study was to investigate the association between body mass index (BMI) and the results of SCARF osteotomy of the first metatarsal for hallux valgus (HV) correction, as the literature on this is scant. This prospective study was carried out between 2011 and 2015. One hundred and thirty-three patients diagnosed with moderate to severe HV underwent a SCARF corrective osteotomy. We divided the patients into two groups according to their BMI: normal and overweight. Postoperative follow-up was two years. All patients were examined twice by two medical doctors simultaneously: pre-operatively and post-operatively at two years' follow-up. Data collected included biometrical records, X-rays [HV angle (HVA), intermetatarsal angle (IMA), American Orthopaedic Foot and Ankle Society Hallux Metatarsophalangeal Index (AOFAS-HMI) and visual analogue scale (VAS) for pain and satisfaction]. There was a significant difference between patient age (p = 0.001), age at onset (p < 0.001) and AOFAS-HMI (p = 0.035) at follow-up. Other parameters were similar in both groups. Regardless of BMI, the radiological outcome was comparable. Despite a significant difference in AOFAS-HMI results, pain and satisfaction level were similar. The authors agreed that high BMI has protective role in the prevalence of HV.

Hydrothermal Carbonization of Microalgae (Chlorococcum sp.) for Porous Carbons With High Cr(VI) Adsorption Performance.

PubMed

Sun, Yuanyuan; Liu, Chang; Zan, Yifan; Miao, Gai; Wang, Hao; Kong, Lingzhao

2018-04-12

Porous carbon adsorbents were prepared from microalgae (Chlorococcum sp.) via directly hydrothermal carbonization coupled with KOH or NH 3 activation for Cr(VI) adsorption. KOH-activated porous carbons exhibit high Cr(VI) adsorption capacities than those obtained via NH 3 modification (370.37 > 95.70 mg/g). The superior Cr(VI) adsorption capacity is due to high surface areas (1784 m 2 /g) and pore volumes of porous carbon with mesoporous and macroporous structures. The Cr(VI) adsorption result was well fitted to the Langmuir model, showing that the removal of Cr(VI) was attributed to the monolayer adsorption of activity site on carbon surface.

A Green Microbial Fuel Cell-Based Biosensor for In Situ Chromium (VI) Measurement in Electroplating Wastewater.

PubMed

Wu, Li-Chun; Tsai, Teh-Hua; Liu, Man-Hai; Kuo, Jui-Ling; Chang, Yung-Chu; Chung, Ying-Chien

2017-10-27

The extensive use of Cr(VI) in many industries and the disposal of Cr(VI)-containing wastes have resulted in Cr(VI)-induced environmental contamination. Cr(VI) compounds are associated with increased cancer risks; hence, the detection of toxic Cr(VI) compounds is crucial. Various methods have been developed for Cr(VI) measurement, but they are often conducted offsite and cannot provide real-time toxicity monitoring. A microbial fuel cell (MFC) is an eco-friendly and self-sustaining device that has great potential as a biosensor for in situ Cr(VI) measurement, especially for wastewater generated from different electroplating units. In this study, Exiguobacterium aestuarii YC211, a facultatively anaerobic, Cr(VI)-reducing, salt-tolerant, and exoelectrogenic bacterium, was isolated and inoculated into an MFC to evaluate its feasibility as a Cr(VI) biosensor. The Cr(VI) removal efficiency of E. aestuarii YC211 was not affected by the surrounding environment (pH 5-9, 20-35 °C, coexisting ions, and salinity of 0-15 g/L). The maximum power density of the MFC biosensor was 98.3 ± 1.5 mW/m² at 1500 Ω. A good linear relationship ( r ² = 0.997) was observed between the Cr(VI) concentration (2.5-60 mg/L) and the voltage output. The developed MFC biosensor is a simple device that can accurately measure Cr(VI) concentrations in the actual electroplating wastewater that is generated from different electroplating units within 30 min with low deviations (-6.1% to 2.2%). After treating the actual electroplating wastewater with the MFC, the predominant family in the biofilm was found to be Bacillaceae (95.3%) and was further identified as the originally inoculated E. aestuarii YC211 by next generation sequencing (NGS). Thus, the MFC biosensor can measure Cr(VI) concentrations in situ in the effluents from different electroplating units, and it can potentially help in preventing the violation of effluent regulations.

A Green Microbial Fuel Cell-Based Biosensor for In Situ Chromium (VI) Measurement in Electroplating Wastewater

PubMed Central

Wu, Li-Chun; Tsai, Teh-Hua; Liu, Man-Hai; Kuo, Jui-Ling; Chang, Yung-Chu

2017-01-01

The extensive use of Cr(VI) in many industries and the disposal of Cr(VI)-containing wastes have resulted in Cr(VI)-induced environmental contamination. Cr(VI) compounds are associated with increased cancer risks; hence, the detection of toxic Cr(VI) compounds is crucial. Various methods have been developed for Cr(VI) measurement, but they are often conducted offsite and cannot provide real-time toxicity monitoring. A microbial fuel cell (MFC) is an eco-friendly and self-sustaining device that has great potential as a biosensor for in situ Cr(VI) measurement, especially for wastewater generated from different electroplating units. In this study, Exiguobacterium aestuarii YC211, a facultatively anaerobic, Cr(VI)-reducing, salt-tolerant, and exoelectrogenic bacterium, was isolated and inoculated into an MFC to evaluate its feasibility as a Cr(VI) biosensor. The Cr(VI) removal efficiency of E. aestuarii YC211 was not affected by the surrounding environment (pH 5–9, 20–35 °C, coexisting ions, and salinity of 0–15 g/L). The maximum power density of the MFC biosensor was 98.3 ± 1.5 mW/m2 at 1500 Ω. A good linear relationship (r2 = 0.997) was observed between the Cr(VI) concentration (2.5–60 mg/L) and the voltage output. The developed MFC biosensor is a simple device that can accurately measure Cr(VI) concentrations in the actual electroplating wastewater that is generated from different electroplating units within 30 min with low deviations (−6.1% to 2.2%). After treating the actual electroplating wastewater with the MFC, the predominant family in the biofilm was found to be Bacillaceae (95.3%) and was further identified as the originally inoculated E. aestuarii YC211 by next generation sequencing (NGS). Thus, the MFC biosensor can measure Cr(VI) concentrations in situ in the effluents from different electroplating units, and it can potentially help in preventing the violation of effluent regulations. PMID:29076985

Reduction of Cr(VI) to Cr(III) by green rust - sulphate

NASA Astrophysics Data System (ADS)

Skovbjerg, L.; Stipp, S.

2003-04-01

Chromium is widely used in industrial processes such as leather tanning, electro-plating and as colour pigments. Unfortunately, hexavalent chromium is both toxic and very soluble so it can be a problem for groundwater resources. Given the right redox conditions, however, Cr(VI) can be reduced to trivalent chromium, which is much less soluble and is an essential trace nutrient. Fe(II), an element common in soil and sediments under anaerobic conditions, can serve as a reducing agent for Cr(VI). Green Rust (GR) is a layered Fe(II),Fe(III)-hydroxide with various anions compensating charge in the interlayers. It is very effective in reducing Cr(VI) to Cr(III). GR exists in nature and is thought to be precursor for the formation of Fe(III)-oxides and oxyhydroxides at the redox boundary. It may be that the formation of GR is a key process in the effectiveness of reactive barriers for groundwater remediation that are based on Fe(0). The purpose of this work is to investigate the mechanisms controlling Cr(VI) reduction by Green Rust, to examine the effect of Cr adsorption and incorporation on GR morphology and composition, and to define the role of parameters such as interlayer anion, initial Cr(VI) concentration and time. We are using freshly synthesised material that has not been dried to avoid structural changes that may accompany dehydration and rehydration. X-Ray Diffraction (XRD) is used to characterise mineral structural changes and Atomic Force Microscopy (AFM), to examine changes in morphology as reactions take place. By adjusting the concentration of Cr(VI), we can control the rate of surface change and we can observe the nanoscale particles directly.

FANCD2 monoubiquitination and activation by hexavalent chromium [Cr(VI)] exposure

PubMed Central

Vilcheck, Susan K.; Ceryak, Susan; O’Brien, Travis J.; Patierno, Steven R.

2007-01-01

Fanconi anemia (FA) is a rare autosomal recessive disorder characterized by congenital abnormalities, progressive bone marrow failure, and cancer susceptibility. FA cells are hypersensitive to DNA crosslinking agents. FA is a genetically heterogeneous disease with at least 11 complementation groups. The eight cloned FA proteins interact in a common pathway with established DNA-damage-response proteins, including BRCA1 and ATM. Six FA proteins (A, C, E, F, G, and L) regulate the monoubiquitination of FANCD2 after DNA damage by crosslinking agents, which targets FANCD2 to BRCA1 nuclear foci containing BRCA2 (FANCD1) and RAD51. Some forms of hexavalent chromium [Cr(VI)] are implicated as respiratory carcinogens and induce several types of DNA lesions, including DNA interstrand crosslinks. We have shown that FA-A fibroblasts are hypersensitive to both Cr(VI)-induced apoptosis and clonogenic lethality. Here we show that Cr(VI) treatment induced monoubiquitination of FANCD2 in normal human fibroblasts, providing the first molecular evidence of Cr(VI)-induced activation of the FA pathway. FA-A fibroblasts demonstrated no FANCD2 monoubiquitination, in keeping with the requirement of FA-A for this modification. We also found that Cr(VI) treatment induced significantly more S-phase-dependent DNA double strand breaks (DSBs), as measured by γ-H2AX expression, in FA-A fibroblasts compared to normal cells. However, and notably, DSBs were repaired equally in both normal and FA-A fibroblasts during recovery from Cr(VI) treatment. While previous research on FA has defined the genetic causes of this disease, it is critical in terms of individual risk assessment to address how cells from FA patients respond to genotoxic insult. PMID:16893675

Diverse functions of myosin VI elucidated by an isoform-specific α-helix domain

PubMed Central

Magistrati, Elisa; Molteni, Erika; Lupia, Michela; Soffientini, Paolo; Rottner, Klemens; Cavallaro, Ugo; Pozzoli, Uberto; Mapelli, Marina; Walters, Kylie J.; Polo, Simona

2016-01-01

Myosin VI functions in endocytosis and cell motility. Alternative splicing of myosin VI mRNA generates two distinct isoform types, myosin VIshort and myosin VIlong, which differ in the C-terminal region. Their physiological and pathological role remains unknown. Here we identified an isoform-specific regulatory helix, named α2-linker that defines specific conformations and hence determines the target selectivity of human myosin VI. The presence of the α2-linker structurally defines a novel clathrin-binding domain that is unique to myosin VIlong and masks the known RRL interaction motif. This finding is relevant to ovarian cancer, where alternative myosin VI splicing is aberrantly regulated, and exon skipping dictates cell addiction to myosin VIshort for tumor cell migration. The RRL interactor optineurin contributes to this process by selectively binding myosin VIshort. Thus the α2-linker acts like a molecular switch that assigns myosin VI to distinct endocytic (myosin VIlong) or migratory (myosin VIshort) functional roles. PMID:26950368

Ankle joint pressure changes in a pes cavovarus model: supramalleolar valgus osteotomy versus lateralizing calcaneal osteotomy.

PubMed

Schmid, Timo; Zurbriggen, Sebastian; Zderic, Ivan; Gueorguiev, Boyko; Weber, Martin; Krause, Fabian G

2013-09-01

A fixed cavovarus foot deformity can be associated with anteromedial ankle arthrosis due to elevated medial joint contact stresses. Supramalleolar valgus osteotomies (SMOT) and lateralizing calcaneal osteotomies (LCOT) are commonly used to treat symptoms by redistributing joint contact forces. In a cavovarus model, the effects of SMOT and LCOT on the lateralization of the center of force (COF) and reduction of the peak pressure in the ankle joint were compared. A previously published cavovarus model with fixed hindfoot varus was simulated in 10 cadaver specimens. Closing wedge supramalleolar valgus osteotomies 3 cm above the ankle joint level (6 and 11 degrees) and lateral sliding calcaneal osteotomies (5 and 10 mm displacement) were analyzed at 300 N axial static load (half body weight). The COF migration and peak pressure decrease in the ankle were recorded using high-resolution TekScan pressure sensors. A significant lateral COF shift was observed for each osteotomy: 2.1 mm for the 6 degrees (P = .014) and 2.3 mm for the 11 degrees SMOT (P = .010). The 5 mm LCOT led to a lateral shift of 2.0 mm (P = .042) and the 10 mm LCOT to a shift of 3.0 mm (P = .006). Comparing the different osteotomies among themselves no significant differences were recorded. No significant anteroposterior COF shift was seen. A significant peak pressure reduction was recorded for each osteotomy: The SMOT led to a reduction of 29% (P = .033) for the 6 degrees and 47% (P = .003) for the 11 degrees osteotomy, and the LCOT to a reduction of 41% (P = .003) for the 5 mm and 49% (P = .002) for the 10 mm osteotomy. Similar to the COF lateralization no significant differences between the osteotomies were seen. LCOT and SMOT significantly reduced anteromedial ankle joint contact stresses in this cavovarus model. The unloading effects of both osteotomies were equivalent. More correction did not lead to significantly more lateralization of the COF or more reduction of peak pressure but a trend was

Removal of Cr(VI) from groundwater by Fe(0)

NASA Astrophysics Data System (ADS)

Gao, Yanjiao; Liu, Rui

2017-11-01

This research was conducted to investigate the treatment of hexavalent chromium (Cr(VI)) by iron powder (Fe(0)) columns of simulated permeable reactive barriers with and without calcium carbonate (CaCO3). Two columns filled with Fe(0) were used as Cr(VI) removal equipment running at a flow velocity of 10 ml/min at room temperature. After 200 days running of the two columns, the results showed that Fe(0) was an effective material for Cr(VI) reduction with an average removal rate of above 84.6%. The performance of Column 2 with CaCO3 was better than Column 1 without CaCO3 in terms of average Cr(VI) removal rate. The presence of CaCO3 buffered the increasing pH caused by Fe(0) corrosion in Column 2 and enhanced the removal rate of Column 2. Scanning Electron Microscopy (SEM) images of Fe(0) in the three stages of running of the two columns illustrated that the coat layer of Column 1 was a little thicker than that of Column 2. Energy-dispersive spectrometry (EDS) results showed that the surface of Fe(0) of Column 2 contained more chromium elements. Raman spectroscopy found that all iron oxide was generated on the Fe(0) surface of Column 1 and Column 2 and chromium class objects were only detected on Fe(0) surface in Column 2.

Spectroscopic characterization of iron-doped II-VI compounds for laser applications

NASA Astrophysics Data System (ADS)

Martinez, Alan

The middle Infrared (mid-IR) region of the electromagnetic spectrum between 2 and 15 ?m has many features which are of interest to a variety of fields such as molecular spectroscopy, biomedical applications, industrial process control, oil prospecting, free-space communication and defense-related applications. Because of this, there is a demand for broadly tunable, laser sources operating over this spectral region which can be easily and inexpensively produced. II-VI semiconductor materials doped with transition metals (TM) such as Co 2+, Cr2+, or Fe2+ exhibit highly favorable spectroscopic characteristics for mid-IR laser applications. Among these TM dopants, Fe2+ has absorption and emission which extend the farthest into the longer wavelength portion of the mid-IR. Fe2+:II-VI crystals have been utilized as gain elements in laser systems broadly tunable over the 3-5.5 microm range [1] and as saturable absorbers to Q -switch [2] and mode-lock [3] laser cavities operating over the 2.7-3 microm. TM:II-VI laser gain elements can be fabricated inexpensively by means of post-growth thermal diffusion with large homogeneous dopant concentration and good optical quality[4,5]. The work outlined in this dissertation will focus on the spectroscopic characterization of TM-doped II-VI semiconductors. This work can be categorized into three major thrusts: 1) the development of novel laser materials, 2) improving and extending applications of TM:II-VI crystals as saturable absorbers, and 3) fabrication of laser active bulk crystals. Because current laser sources based on TM:II-VI materials do not cover the entire mid-IR spectral region, it is necessary to explore novel laser sources to extend available emissions toward longer wavelengths. The first objective of this dissertation is the spectroscopic characterization of novel ternary host crystals doped with Fe2+ ions. Using crystal field engineering, laser materials can be prepared with emissions placed in spectral regions not

Study on the DNA-protein crosslinks induced by chromium (VI) in SPC-A1

NASA Astrophysics Data System (ADS)

Liu, Yanqun; Ding, Jianjun; Lu, Xiongbing; You, Hao

2018-01-01

Objective: This study was designed to investigate the effect of chromium (VI) on DNA-protein crosslinks (DPC) of SPC-A1 cells. Methods: We exposed SPC-A1 cells were cultured in 1640 medium and treated with the SPC-A1 cells in vitro to different concentrations of Hexavalent chromium Cr(VI) for 2h, the KC1-SDS precipitation assay were used to measure the DNA-protein cross-linking effect. Results: All the different concentrations of Cr(VI) could cause the increase of DPC coefficient in SPC-A1 cells. But this effect was not significant (P>0.05) at low concentrations; while in high concentration Cr(VI) induced SPC-A1 cells could produce DNA-protein cross-linking effect significantly (P<0.05). Conclusions: chromium (VI) could induce DNA-protein crosslink.

A modified model for calculating lattice thermal expansion of I{sub 2}-IV-VI{sub 3} and I{sub 3}-V-VI{sub 4} tetrahedral compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Omar, M.S.

2007-05-03

A general empirical formula was found for calculating lattice thermal expansion for compounds having their properties extended for compound groups having different mean ionicity as well as more than one type of cation atoms with that of different numbers of them such as I{sub 2}-IV-VI{sub 3} and I{sub 3}-V-VI{sub 4}. The difference in the valence electrons for cations and anions in the compound was used to correlate the deviations caused by the compound ionicity. The ionicity effects, which are due to their different numbers for their types, were also added to the correlation equation. In general, the lattice thermal expansionmore » for a compound semiconductor can be calculated from a relation containing melting point, mean atomic distance and number of valence electrons for the atoms forming the compound. The mean ionicity for the group compounds forming I{sub 2}-IV-VI{sub 3} was found to be 0.323 and 0.785 for the ternary group compounds of I{sub 3}-V-VI{sub 4}.« less

Removal of GaAs growth substrates from II-VI semiconductor heterostructures

NASA Astrophysics Data System (ADS)

Bieker, S.; Hartmann, P. R.; Kießling, T.; Rüth, M.; Schumacher, C.; Gould, C.; Ossau, W.; Molenkamp, L. W.

2014-04-01

We report on a process that enables the removal of II-VI semiconductor epilayers from their GaAs growth substrate and their subsequent transfer to arbitrary host environments. The technique combines mechanical lapping and layer selective chemical wet etching and is generally applicable to any II-VI layer stack. We demonstrate the non-invasiveness of the method by transferring an all-II-VI magnetic resonant tunneling diode. High resolution x-ray diffraction proves that the crystal integrity of the heterostructure is preserved. Transport characterization confirms that the functionality of the device is maintained and even improved, which is ascribed to completely elastic strain relaxation of the tunnel barrier layer.

AR4VI: AR as an Accessibility Tool for People with Visual Impairments.

PubMed

Coughlan, James M; Miele, Joshua

2017-10-01

Although AR technology has been largely dominated by visual media, a number of AR tools using both visual and auditory feedback have been developed specifically to assist people with low vision or blindness - an application domain that we term Augmented Reality for Visual Impairment (AR4VI). We describe two AR4VI tools developed at Smith-Kettlewell, as well as a number of pre-existing examples. We emphasize that AR4VI is a powerful tool with the potential to remove or significantly reduce a range of accessibility barriers. Rather than being restricted to use by people with visual impairments, AR4VI is a compelling universal design approach offering benefits for mainstream applications as well.

Spitznävi: unterschiedliche klinische, dermatoskopische und histopathologische Merkmale in der Kindheit.

PubMed

Dika, Emi; Neri, Iria; Fanti, Pier Alessandro; Barisani, Alessia; Ravaioli, Giulia Maria; Patrizi, Annalisa

2017-01-01

Die Charakterisierung der klinischen Merkmale und des biologischen Potenzials von Spitznävi hat in den letzten Jahrzehnten breites Interesse gefunden. Das Ziel dieser Arbeit ist die Beschreibung der klinischen und dermatoskopischen Merkmale von Spitznävi sowie des klinischen Ergebnisses nach chirurgischer Exzision von Spitznävi in drei pädiatrischen Altersgruppen. Restrospektive Studie zur Analyse von klinischen Merkmalen, videodermatoskopischen Bildern, histopathologischen Diagnosen und Behandlungsergebnissen. Der Grad der Pigmentierung wurde sowohl klinisch als auch histopathologisch beurteilt. Bei 71 Patienten wurden 72 spitzoide Neoplasien entfernt. Videodermatologische Bilder lagen für 41 Patienten vor. Das Muster der Pigmentierung korrelierte signifikant mit dem Alter der Patienten: Hyperpigmentierte Läsionen waren bei Vorschulkindern selten, bei Patienten von 7 bis 12 Jahren und ab 13 Jahren dagegen häufiger. Eine histopathologische Diagnose von atypischen Spitznävi wurde selten durchgeführt. Keiner der Patienten, bei denen ursprünglich ein atypischer Spitznävus diagnostiziert worden war, entwickelte ein Lokalrezidiv oder Metastasen während der anschließenden Nachbeobachtung. Pigmentierte Spitznävi traten im Alter ab 13 Jahren häufiger auf. Die Studie bestätigt andere Berichte über die Altersverteilung von Pigmentierungsmustern und hebt die geringe Anzahl atypischer Spitznävi bei pädiatrischen Patienten hervor sowie das Ausbleiben von Rezidiven bei der langfristigen Nachbeobachtung. © 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

Inhibition of bone resorption by Tanshinone VI isolated from Salvia miltiorrhiza Bunge.

PubMed

Nicolin, V; Dal Piaz, F; Nori, S L; Narducci, P; De Tommasi, N

2010-05-10

During the last decade, a more detailed knowledge of molecular mechanisms involved in osteoclastogenesis has driven research efforts in the development and screening of compound libraries of several small molecules that specifically inhibit the pathway involved in the commitment of the osteoclast precursor cells. Natural compounds that suppress osteoclast differentiation may have therapeutic value in treating osteoporosis and other bone erosive diseases such as rheumatoid arthritis or metastasis associated with bone loss. In ongoing investigation into anti-osteoporotic compounds from natural products we have analyzed the effect of Tanshinone VI on osteoclasts differentiation, using a physiologic three-dimensional osteoblast/bone marrow model of cell co-culture. Tanshinone VI is an abietane diterpene extracted from the root of Salvia miltiorrhiza Bunge (Labiatae), a Chinese traditional crude drug, "Tan-Shen". Tashinone has been widely used in clinical practice for the prevention of cardiac diseases, arthritis and other inflammation-related disorders based on its pharmacological actions in multiple tissues. Although Tanshinone VI A has been used as a medicinal agent in the treatment of many diseases, its role in osteoclast-related bone diseases remains unknown. We showed previously that Tanshinone VI greatly inhibits osteoclast differentiation and suppresses bone resorption through disruption of the actin ring; subsequently, we intended to examine the precise inhibitory mechanism of Tanshinone VI on osteoclast differentiating factor. This study shows, for the first time, that Tanshinone VI prevents osteoclast differentiation by inhibiting RANKL expression and NFkB induction.

Oxidation of indometacin by ferrate (VI): kinetics, degradation pathways, and toxicity assessment.

PubMed

Huang, Junlei; Wang, Yahui; Liu, Guoguang; Chen, Ping; Wang, Fengliang; Ma, Jingshuai; Li, Fuhua; Liu, Haijin; Lv, Wenying

2017-04-01

The oxidation of indometacin (IDM) by ferrate(VI) (Fe(VI)) was investigated to determine the reaction kinetics, transformation products, and changes in toxicity. The reaction between IDM and Fe(VI) followed first-order kinetics with respect to each reactant. The apparent second-order rate constants (k app ) decreased from 9.35 to 6.52 M -1  s -1 , as the pH of the solution increased from 7.0 to 10.0. The pH dependence of k app might be well explained by considering the species-specific rate constants of the reactions of IDM with Fe(VI). Detailed product studies using liquid chromatography-tandem mass spectrometry (LC-MS/MS) indicated that the oxidation products were primarily derived from the hydrolysis of amide linkages, the addition of hydroxyl groups, and electrophilic oxidation. The toxicity of the oxidation products was evaluated using the Microtox test, which indicated that transformation products exhibited less toxicity to the Vibrio fischeri bacteria. Quantitative structure-activity relationship (QSAR) analysis calculated by the ecological structure activity relationship (ECOSAR) revealed that all of the identified products exhibited lower acute and chronic toxicity than the parent pharmaceutical for fish, daphnid, and green algae. Furthermore, Fe(VI) was effective in the degradation IDM in water containing carbonate ions or fulvic acid (FA), and in lake water samples; however, higher Fe(VI) dosages would be required to completely remove IDM in lake water in contrast to deionized water.

ViSC Social Competence Program

ERIC Educational Resources Information Center

Strohmeier, Dagmar; Hoffmann, Christine; Schiller, Eva-Maria; Stefanek, Elisabeth; Spiel, Christiane

2012-01-01

The ViSC Social Competence Program has been implemented in Austrian schools within the scope of a national strategy plan, Together Against Violence. The program is a primary preventive program designed for grades 5 to 8. The prevention of aggression and bullying is defined as a school development task, and the initial implementation of the program…

The VI-SENSE-vaginal discharge self-test to facilitate management of vaginal symptoms.

PubMed

Geva, Adam; Bornstein, Jacob; Dan, Michael; Shoham, Hadar Kessary; Sobel, Jack D

2006-11-01

This study was undertaken to evaluate a diagnostic panty liner (VI-SENSE) (Common Sense, Caesarea, Israel) developed to facilitate diagnosis of vaginal infections by detecting disordered acidity level. Five hundred sixteen women with vulvovaginal symptoms were enrolled. Final clinical diagnosis included Amsel criteria, Gram stain analysis, pH determination, and Trichomonas vaginalis and Candida culture. VI-SENSE strip color status estimated by patients was compared with clinical diagnosis and pH measurement by using nitrazine paper. Statistical analysis included sensitivity and specificity calculations. The VI-SENSE test was positive in 226 of 249 patients (90.8%) with bacterial vaginosis or trichomoniasis. Nitrazine pH paper revealed elevated pH in 165 (66.5%) and the amine test was positive in 160 (64.3%) patients. The VI-SENSE test was negative in 217 of 267 patients (81.3%) without trichomoniasis or bacterial vaginosis. The VI-SENSE was positive in 85 of 92 women (92%), with mixed vaginal infection including Candida and bacterial vaginosis or trichomoniasis. Amine test, nitrazine pH paper and physician diagnosis relying only on speculum examination were inferior and positive in only 65 (70%), 59 (64%), and 66 (72%) patients, respectively. The VI-SENSE test was found to be superior to traditional individual tests in facilitating preliminary diagnosis of vaginal infections.

Unconstrained steps of myosin VI appear longest among known molecular motors.

PubMed

Ali, M Yusuf; Homma, Kazuaki; Iwane, Atsuko Hikikoshi; Adachi, Kengo; Itoh, Hiroyasu; Kinosita, Kazuhiko; Yanagida, Toshio; Ikebe, Mitsuo

2004-06-01

Myosin VI is a two-headed molecular motor that moves along an actin filament in the direction opposite to most other myosins. Previously, a single myosin VI molecule has been shown to proceed with steps that are large compared to its neck size: either it walks by somehow extending its neck or one head slides along actin for a long distance before the other head lands. To inquire into these and other possible mechanism of motility, we suspended an actin filament between two plastic beads, and let a single myosin VI molecule carrying a bead duplex move along the actin. This configuration, unlike previous studies, allows unconstrained rotation of myosin VI around the right-handed double helix of actin. Myosin VI moved almost straight or as a right-handed spiral with a pitch of several micrometers, indicating that the molecule walks with strides slightly longer than the actin helical repeat of 36 nm. The large steps without much rotation suggest kinesin-type walking with extended and flexible necks, but how to move forward with flexible necks, even under a backward load, is not clear. As an answer, we propose that a conformational change in the lifted head would facilitate landing on a forward, rather than backward, site. This mechanism may underlie stepping of all two-headed molecular motors including kinesin and myosin V.

ORFEUS spectroscopy of the O BT VI lines in symbiotic stars and the Raman scattering process

NASA Astrophysics Data System (ADS)

Schmid, H. M.; Krautter, J.; Appenzeller, I.; Barnstedt, J.; Dumm, T.; Fromm, A.; Gölz, M.; Grewing, M.; Gringel, W.; Haas, C.; Hopfensitz, W.; Kappelmann, N.; Krämer, G.; Lindenberger, A.; Mandel, H.; Mürset, U.; Schild, H.; Schmutz, W.; Widmann, H.

1999-08-01

We present orfeus spectra of the O vi lambda lambda 1032,1038 emission lines in the symbiotic stars AG Dra, V1016 Cyg, RR Tel, CD-43(deg) 14304, AG Peg and Z And. The O vi emission lines can convert into broad and highly polarized emission lines at lambda 6825 and lambda 7082 in a Raman scattering process by neutral hydrogen. From a comparison of direct and Raman scattered radiation we extract new information on the scattering geometry in symbiotic systems. The nebular O vi emission lines are in all objects redshifted by about +40 km s(-1) . This can be explained as a radiative line transfer effect in a slowly expanding emission region. A comparable redshift is measured in the Raman scattered O vi lines. In AG Peg the O vi emissions show beside a narrow nebular line a broad component from a fast stellar wind outflow. Many interstellar absorption lines of molecular hydrogen are detected, particularly near the O vi lambda 1038 component. With model calculations we investigate their impact on the O vi lines. From the dereddened line fluxes of the direct and Raman scattered O vi lines we derive the scattering efficiency, which is defined as photon flux ratio N_Raman/N_O VI. The efficiencies derived for RR Tel, V1016 Cyg and Z And indicate that about 30% of the released O vi lambda 1032 photons interact with the neutral scattering region. The efficiencies for AG Dra and CD-43(deg14304) are much higher, which may suggest that the O vi nebulosity is embedded in a H(0) -region. The D-type system RR Tel shows strong line profile differences between the direct O vi emission, which is single-peaked, and the Raman scattered emission, which is double-peaked. This indicates that the neutral scattering region in RR Tel ``sees'' different O vi line profiles, implying that the O vi nebulosity is far from spherically symmetric. In a tentative model we suggest for RR Tel an O vi flow pattern where material streams from the cool giant towards the hot component, which further

Chromium(VI) sorption efficiency of acid-activated banana peel over organo-montmorillonite in aqueous solutions.

PubMed

Ashraf, Anam; Bibi, Irshad; Niazi, Nabeel Khan; Ok, Yong Sik; Murtaza, Ghulam; Shahid, Muhammad; Kunhikrishnan, Anitha; Li, Dongwei; Mahmood, Tariq

2017-07-03

In the present study, we examined sorption of chromate (Cr(VI)) to acid-activated banana peel (AABP) and organo-montmorillonite (O-mont) as a function of pH, initial Cr(VI) concentration at a sorbent dose of 4 g L -1 and at 20 ± 1°C in aqueous solutions. In sorption edge experiments, maximum Cr(VI) removal was obtained at pH 3 after 2 hours by AABP and O-mont (88% and 69%). Sorption isotherm data showed that the sorption capacity of AABP was higher than O-mont (15.1 vs. 6.67 mg g -1 , respectively, at pH 4). Freundlich and Langmuir models provided the best fits to describe Cr(VI) sorption onto AABP (R 2 = 0.97) and O-mont (R 2 = 0.96). Fourier transform infrared spectroscopy elucidated that for AABP mainly the -OH, -COOH, -NH 2 , and for O-mont intercalated amines and -OH surface functional groups were involved in Cr(VI) sorption. The scanning electron microscopy combined with energy dispersive X-ray spectroscopy (SEM-EDX) analyses, although partly, indicate that the (wt. %) proportion of cations (e.g., Ca, Mg) in AABP decreased after Cr(VI) sorption. This may be due to ion exchange of chromite (Cr(III)) (produced from Cr(VI) reduction) with cationic elements in AABP. Also, Cr(VI) desorption (using phosphate solution) from AABP was lower (29%) than that from O-mont (51%) up to the third regeneration cycle. This bench scale comparative study highlights that the utilization of widely available and low-cost acid-activated biomaterials has a greater potential than organo-clays for Cr(VI) removal in aqueous media. However, future studies are warranted to precisely delineate different mechanisms of Cr(VI) sorption/reduction by acid-activated biomaterials and organo-clays.

Structural and elastic properties of AIBIIIC 2 VI semiconductors

NASA Astrophysics Data System (ADS)

Kumar, V.; Singh, Bhanu P.

2018-01-01

The plane wave pseudo-potential method within density functional theory has been used to calculate the structural and elastic properties of AIBIIIC 2 VI semiconductors. The electronic band structure, density of states, lattice constants (a and c), internal parameter (u), tetragonal distortion (η), energy gap (Eg), and bond lengths of the A-C (dAC) and B-C (dBC) bonds in AIBIIIC 2 VI semiconductors have been calculated. The values of elastic constants (Cij), bulk modulus (B), shear modulus (G), Young's modulus (Y), Poisson's ratio (υ), Zener anisotropy factor (A), Debye temperature (ϴD) and G/B ratio have also been calculated. The values of all 15 parameters of CuTlS2 and CuTlSe2 compounds, and 8 parameters of 20 compounds of AIBIIIC 2 VI family, except AgInS2 and AgInSe2, have been calculated for the first time. Reasonably good agreement has been obtained between the calculated, reported and available experimental values.

Treatment of selected pharmaceuticals by ferrate(VI): performance, kinetic studies and identification of oxidation products.

PubMed

Zhou, Zhengwei; Jiang, Jia-Qian

2015-03-15

The performance of ferrate(VI) in treating sulfamethoxazole (SMX), diclofenac (DCF), carbamazepine (CBZ) and bezafibrate (BZF) in test solutions containing the four compounds was investigated. A series of jar-test experiments was performed on a bench-scale at pH 6-9 and at a ferrate(VI) dose of 1-5 mg Fe/L. The results suggested that ferrate(VI) can effectively remove SMX, DCF and CBZ from the test solutions, with greater than 80% removal under optimum conditions. However, the removal efficiency of BZF was very low, less than 25% under the studied conditions. Increasing the dose of ferrate(VI) improved the treatment performance, while the influence of solution pH on ferrate(VI) performance varied among the different target compounds. Ferrate(VI) demonstrated the highest reactivity with SMX at pH 8 and pH 9 (20 °C), with apparent second-order rate constants of 360±17 M(-1) s(-1) and 1.26±0.02 M(-1) s(-1), respectively. However, BZF showed the lowest removal by ferrate(VI) with the smallest rate constants (less than 0.5 M(-1) s(-1)) at pH 8 and pH 9. Furthermore, a number of oxidation products (OPs) of SMX, DCF and CBZ during ferrate(VI) oxidation were detected by liquid chromatography and mass spectrometry (LC-MS), and their degradation pathways were tentatively proposed. No OPs of BZF were detected during ferrate(VI) oxidation. Copyright © 2014 Elsevier B.V. All rights reserved.

Desegregating America's Colleges and Universities. Title VI Regulation of Higher Education.

ERIC Educational Resources Information Center

Williams, John B., III, Ed.

Issues concerning desegregation of U.S. campuses and federal regulation of higher education under Title VI of the Civil Rights Act of 1964 are considered in 12 essays. Titles and authors are as follows: "Title VI Regulation of Higher Education" (John B. Williams, III); "The Production of Black Doctoral Recipients: A Description of…

The Oxidation of Secondary Alcohols with Cr(VI): A Spectrophotometric Method.

ERIC Educational Resources Information Center

Mason, Timothy J.; And Others

1985-01-01

Background information, procedures, and typical results are provided for an experiment in which spectrophotometry is used to examine the oxidation of secondary alcohols using chromium (VI). The overall change in oxidation state of chromium during the reaction is VI to III, corresponding to the familiar color change from orange to green. (JN)

Removing uranium (VI) from aqueous solution with insoluble humic acid derived from leonardite.

PubMed

Meng, Fande; Yuan, Guodong; Larson, Steven L; Ballard, John H; Waggoner, Charles A; Arslan, Zikri; Han, Fengxiang X

2017-12-01

The occurrence of uranium (U) and depleted uranium (DU)-contaminated wastes from anthropogenic activities is an important environmental problem. Insoluble humic acid derived from leonardite (L-HA) was investigated as a potential adsorbent for immobilizing U in the environment. The effect of initial pH, contact time, U concentration, and temperature on U(VI) adsorption onto L-HA was assessed. The U(VI) adsorption was pH-dependent and achieved equilibrium in 2 h. It could be well described with pseudo-second-order model, indicating that U(VI) adsorption onto L-HA involved chemisorption. The U(VI) adsorption mass increased with increasing temperature with maximum adsorption capacities of 91, 112 and 120 mg g -1 at 298, 308 and 318 K, respectively. The adsorption reaction was spontaneous and endothermic. We explored the processes of U(VI) desorption from the L-HA-U complex through batch desorption experiments in 1 mM NaNO 3 and in artificial seawater. The desorption process could be well described by pseudo-first-order model and reached equilibrium in 3 h. L-HA possessed a high propensity to adsorb U(VI). Once adsorbed, the release of U(VI) from L-HA-U complex was minimal in both 1 mM NaNO 3 and artificial seawater (0.06% and 0.40%, respectively). Being abundant, inexpensive, and safe, L-HA has good potential for use as a U adsorbent from aqueous solution or immobilizing U in soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effects of chromium(VI) on the thioredoxin system: Implications for redox regulation

PubMed Central

Myers, Charles R.

2014-01-01

Hexavalent chromium [Cr(VI)] compounds are highly redox active and have long been recognized as potent cytotoxins and carcinogens. The intracellular reduction of Cr(VI) generates reactive Cr intermediates, which are themselves strong oxidants, as well as superoxide, hydrogen peroxide, and hydroxyl radical. These probably contribute to the oxidative damage and effects on redox-sensitive transcription factors that have been reported. However, the identification of events that initiate these signaling changes has been elusive. More recent studies show that Cr(VI) causes irreversible inhibition of thioredoxin reductase (TrxR) and oxidation of thioredoxin (Trx) and peroxiredoxin (Prx). Mitochondrial Trx2/Prx3 are more sensitive to Cr(VI) treatment than cytosolic Trx1/Prx1, although both compartments show thiol oxidation with higher doses or longer treatments. Thiol redox proteomics demonstrate that Trx2, Prx3, and Trx1 are among the most sensitive proteins in cells to Cr(VI) treatment. Their oxidation could therefore represent initiating events that have widespread implications for protein thiol redox control and for multiple aspects of redox signaling. This review summarizes the effects of Cr(VI) on the TrxR/Trx system and how these events could influence a number of downstream redox signaling systems that are influenced by Cr(VI) exposure. Some of the signaling events discussed include the activation of apoptosis signal regulating kinase and MAP kinases (p38 and JNK) and the modulation of a number of redox-sensitive transcription factors including AP-1, NF-κB, p53, and Nrf2. PMID:22542445

The juxtamembrane domain of the E-cadherin cytoplasmic tail contributes to its interaction with Myosin VI

PubMed Central

Mangold, Sabine; Norwood, Suzanne J.; Yap, Alpha S.; Collins, Brett M.

2012-01-01

We recently identified the atypical myosin, Myosin VI, as a component of epithelial cell-cell junctions that interacts with E-cadherin. Recombinant proteins bearing the cargo-binding domain of Myosin VI (Myo VI-CBD) or the cytoplasmic tail of E-cadherin can interact directly with one another. In this report we further investigate the molecular requirements of the interaction between Myo VI-CBD and E-cadherin combining truncation mutation analysis with in vitro binding assays. We report that a short (28 amino acid) juxtamembrane region of the cadherin cytoplasmic tail is sufficient to bind Myo VI-CBD. However, central regions of the cadherin tail adjacent to the juxtamembrane sequence also display binding activity for Myo VI-CBD. It is therefore possible that the cadherin tail bears two binding sites for Myosin VI, or an extended binding site that includes the juxtamembrane region. Nevertheless, our biochemical data highlight the capacity for the juxtamembrane region to interact with functionally-significant cytoplasmic proteins. PMID:23007415

Removal of Cr(VI) by nanoscale zero-valent iron (nZVI) from soil contaminated with tannery wastes.

PubMed

Singh, Ritu; Misra, Virendra; Singh, Rana Pratap

2012-02-01

The illegal disposal of tannery wastes at Rania, Kanpur has resulted in accumulation of hexavalent chromium [Cr(VI)], a toxic heavy metal in soil posing risk to human health and environment. 27 soil samples were collected at various depths from Rania for the assessment of Cr(VI) level in soil. Out of 27 samples, five samples had shown significant level of Cr(VI) with an average concentration of 15.84 mg Kg(-1). Varied doses of nanoscale zero-valent iron (nZVI) were applied on Cr(VI) containing soil samples for remediation of Cr(VI). Results showed that 0.10 g L(-1) nZVI completely reduces Cr(VI) within 120 min following pseudo first order kinetics. Further, to test the efficacy of nZVI in field, soil windrow experiments were performed at the contaminated site. nZVI showed significant Cr(VI) reduction at field also, indicating it an effective tool for managing sites contaminated with Cr(VI).

Removal of chromium (VI) from electroplating wastewater using an anion exchanger derived from rice straw.

PubMed

Cao, Wei; Dang, Zhi; Yia, Xiao-Yun; Yang, Chen; Lu, Gui-Ning; Liu, Yun-Feng; Huang, Se-Yan; Zheng, Liu-Chun

2013-01-01

An anion exchanger from rice straw was used to remove Cr (VI) from synthetic wastewater and electroplating effluent. The exchanger was characterized using Fourier transform infrared (FTIR) spectrum and scanning electron microscopy (SEM), and it was found that the quaternary amino group and hydroxyl group are the main functional groups on the fibrous surface of the exchanger. The effect of contact time, initial concentration and pH on the removal of Cr (VI), and adsorption isotherms at different temperature, was investigated. The results showed that the removal of Cr (VI) was very rapid and was significantly affected by the initial pH of the solution. Although acidic conditions (pH = 2-6) facilitated Cr (VI) adsorption, the exchanger was effective in neutral solution and even under weak base conditions. The equilibrium data fitted well with Langmuir adsorption model, and the maximum Cr (VI) adsorption capacities at pH 6.4 were 0.35, 0.36 and 0.38 mmol/g for 15, 25 and 35 degrees C, respectively. The exchanger was finally tested with real electroplating wastewater, and at sorbent dosage of 10 g/L, the removal efficiencies for Cr (VI) and total Cr were 99.4% and 97.8%, respectively. In addition, the positive relationship between adsorbed Cr (VI) and desorbed Cl- suggested that Cr (VI) was mainly removed by ion exchange with chlorine.

Occurrence of Cr(VI) in drinking water of Greece and relation to the geological background.

PubMed

Kaprara, E; Kazakis, N; Simeonidis, K; Coles, S; Zouboulis, A I; Samaras, P; Mitrakas, M

2015-01-08

This study provides a survey on potential Cr(VI) exposure attributed to drinking water in Greece. For this reason, a wide sampling and chemical analysis of tap waters from around 600 sites, supplied by groundwater resources, was conducted focusing on areas in which the geological substrate is predominated by ultramafic minerals. Results indicate that although violations of the current chromium regulation limit in tap water are very rare, 25% of cases showed Cr(VI) concentrations above 10 μg/L, whereas Cr(VI) was detectable in 70% of the samples (>2 μg/L). Mineralogy and conditions of groundwater reservoirs were correlated to suggest a possible Cr(VI) leaching mechanism. Higher Cr(VI) values are observed in aquifers in alluvial and neogene sediments of serpentine and amphibolite, originating from the erosion of ophiolithic and metamorphic rocks. In contrast, Cr(VI) concentration in samples from ophiolithic and metamorphic rocks was always below 10 μg/L due to both low contact time and surface area, as verified by low conductivity and salt concentration values. These findings indicate that under specific conditions, pollution of water by Cr(VI) is favorable by a slow MnO2-catalyzed oxidation of soluble Cr(III) to Cr(VI) in which manganese products [Mn(III)/Mn(II)] are probably re-oxidized by oxygen. Copyright © 2014 Elsevier B.V. All rights reserved.

Comparison of Fe(VI) (FeO4(2-)) and ozone in inactivating Bacillus subtilis spores.

PubMed

Makky, Essam A; Park, Gui-Su; Choi, Ik-Won; Cho, Sung-Il; Kim, Hyunook

2011-05-01

The protozoan parasites such as Cryptosporidiumparvum and Giardialamblia have been recognized as a frequent cause of recent waterborne disease outbreaks because of their strong resistance against chlorine disinfection. In this study, ozone and Fe(VI) (i.e., FeO(4)(2-)) were compared in terms of inactivation efficiency for Bacillus subtilis spores which are commonly utilized as an indicator of protozoan pathogens. Both oxidants highly depended on water pH and temperature in the spore inactivation. Since redox potential of Fe(VI) is almost the same as that of ozone, spore inactivation efficiency of Fe(VI) was expected to be similar with that of ozone. However, it was found that ozone was definitely superior over Fe(VI): at pH 7 and 20°C, ozone with the product of concentration×contact time (C¯T) of 10mgL(-1)min inactivate the spores more than 99.9% within 10min, while Fe(VI) with C¯T of 30mgL(-1) min could inactivate 90% spores. The large difference between ozone and Fe(VI) in spore inactivation was attributed mainly to Fe(III) produced from Fe(VI) decomposition at the spore coat layer which might coagulate spores and make it difficult for free Fe(VI) to attack live spores. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

Effects of toe-in and toe-in with wider step width on level walking knee biomechanics in varus, valgus, and neutral knee alignments.

PubMed

Bennett, Hunter J; Shen, Guangping; Cates, Harold E; Zhang, Songning

2017-12-01

Increased peak external knee adduction moments exist for individuals with knee osteoarthritis and varus knee alignments, compared to healthy and neutrally aligned counterparts. Walking with increased toe-in or increased step width have been individually utilized to successfully reduce 1st and 2nd peak knee adduction moments, respectfully, but have not previously been combined or tested among all alignment groups. The purpose of this study was to compare toe-in only and toe-in with wider step width gait modifications in individuals with neutral, valgus, and varus alignments. Thirty-eight healthy participants with confirmed varus, neutral, or valgus frontal-plane knee alignment through anteroposterior radiographs, performed level walking in normal, toe-in, and toe-in with wider step width gaits. A 3×3 (group×intervention) mixed model repeated measures ANOVA compared alignment groups and gait interventions (p<0.05). The 1st peak knee adduction moment was reduced in both toe-in and toe-in with wider step width compared to normal gait. The 2nd peak adduction moment was increased in toe-in compared to normal and toe-in with wider step width. The adduction impulse was also reduced in toe-in and toe-in with wider step width compared to normal gait. Peak knee flexion and external rotation moments were increased in toe-in and toe-in with wider step width compared to normal gait. Although the toe-in with wider step width gait seems to be a viable option to reduce peak adduction moments for varus alignments, sagittal, and transverse knee loadings should be monitored when implementing this gait modification strategy. Copyright © 2017 Elsevier B.V. All rights reserved.

Collagen VI disorders: Insights on form and function in the extracellular matrix and beyond.

PubMed

Lamandé, Shireen R; Bateman, John F

2017-12-22

Mutations in the three canonical collagen VI genes, COL6A1, COL6A2 and COL6A3, cause a spectrum of muscle disease from Bethlem myopathy at the mild end to the severe Ullrich congenital muscular dystrophy. Mutations can be either dominant or recessive and the resulting clinical severity is influenced by the way mutations impact the complex collagen VI assembly process. Most mutations are found towards the N-terminus of the triple helical collagenous domain and compromise extracellular microfibril assembly. Outside the triple helix collagen VI is highly polymorphic and discriminating mutations from rare benign changes remains a major diagnostic challenge. Collagen VI deficiency alters extracellular matrix structure and biomechanical properties and leads to increased apoptosis and oxidative stress, decreased autophagy, and impaired muscle regeneration. Therapies that target these downstream consequences have been tested in a collagen VI null mouse and also in small human trials where they show modest clinical efficacy. An important role for collagen VI in obesity, cancer and diabetes is emerging. A major barrier to developing effective therapies is the paucity of information about how collagen VI deficiency in the extracellular matrix signals the final downstream consequences - the receptors involved and the intracellular messengers await further characterization. Copyright © 2017 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.