bluuebunny/crossref_metadata_2025 huggingface dataset:
Escape Hepatitis B Virus Mutations in Recipients of Antibody To Hepatitis B Core Antigen–Positive Liver Grafts Receiving Hepatitis B Immunoglobulins
Authors: Roche Bruno , Roque-Afonso Anne-Marie , Sebagh Mylene , Delvart Valerie , Duclos-Vallee Jean Charles , Castaing Denis , Samuel Didier
Published: April 2010

A variety of prophylactic strategies are used to prevent the risk of hepatitis B virus (HBV) transmission from antibody to hepatitis B core antigen (anti-HBc)–positive donors. The mechanisms underlying the failure of HBV immunoglobulin monoprophylaxis have been poorly evaluated. Seventy-seven anti-HBc–positive grafts were used in 21 hepatitis B surface antigen (HBsAg)–positive recipients and 56 HBsAg-negative recipients. HBsAg-positive recipients received prophylaxis comprising hepatitis B immunoglobulins (HBIG) and antiviral agents, 45 HBsAg-negative recipients received a modified HBIG regimen, and 11 HBsAg-negative recipients received no prophylaxis. Both donors and recipients were screened for HBsAg, antibody to HBsAg (anti-HBs) and anti-HBc in their sera and for HBV DNA in both their sera and liver. S gene mutations were investigated after HBV reinfection. HBV infection occurred in 15 HBsAg-negative recipients (19.4%) at a median interval of 16 months (range = 6-67 months) post-transplant and in none of the HBsAg-positive recipients. HBV infections were observed in 31.6% of HBV-naive recipients and 7.7% of HBV-immune recipients receiving HBIG prophylaxis versus 100% of HBV-naive recipients (P = 0.0068) and 33% of HBV-immune recipients (P = 0.08) with no such prophylaxis. S gene mutations were identified in 9 recipients. In conclusion, priority should be given to using anti-HBc positive grafts for HBsAg-positive or HBV-immune recipients. Our study has confirmed the high risk of HBV transmission to naive recipients. HBIG monoprophylaxis was associated with a significant risk of de novo HBV infection and HBV escape mutations. In these patients, we therefore recommend prophylaxis with lamivudine or new nucleos(t)ides analogues. The potential benefits of HBIG prophylaxis combined with antiviral drugs require further evaluations. Long-term prophylaxis is needed because of the long interval of de novo HBV infection post-transplant in some patients. Liver Transpl 16:885–894, 2010. © 2010 AASLD.
Prioritizing Hits with Appropriate Trade‐Offs Between HIV‐1 Reverse Transcriptase Inhibitory Efficacy and MT4 Blood Cells Toxicity Through Desirability‐Based Multiobjective Optimization and Ranking
Authors: Cruz‐Monteagudo Maykel , PhamThe Hai , Cordeiro M. Natalia D. S. , Borges Fernanda
Published: April 2010

Nonnucleoside reverse transcriptase (RT) inhibitors (NNRTIs) constitute a promising therapeutic option for AIDS. However, the emergence of virus‐NNRTIs resistance was found to be a major problem in the field. Toward that goal, a “knock‐out” strategy stands out between the several options to circumvent the problem. However the high drug or drug‐drug concentrations often used generate additional safety concerns. The need for approaches able to early integrate drug‐ or lead‐likeness, toxicity and bioavailability criteria in the drug discovery phase is an emergent issue. Given that, we propose a combined strategy based on desirability‐based multiobjective optimization (MOOP) and ranking for the prioritization of HIV‐1 NNRTIs hits with appropriate trade‐offs between inhibitory efficacy over the HIV‐1 RT and toxic effects over MT4 blood cells. Through the MOOP process, the theoretical levels of the predictive variables required to reach a desirable RT inhibitor candidate with the best possible compromise between efficacy and safety were found. This information is used as a pattern to rank the library of compounds according to a similarity‐based structural criterion, providing a ranking quality of 64 %/71 %/73 % in training/validation/test set. A comparative study between the sequential, parallel and multiobjective virtual screening revealed that the multiobjective approach can outperform the other approaches. These results suggest that the identification of NNRTIs hits with appropriate trade‐offs between potency and safety, rather than fully optimized hits solely based on potency, can facilitate the hit to lead transition and increase the likelihood of the candidate to evolve into a successful antiretroviral drug.
Electrical stimulation impairs early functional recovery and accentuates skeletal muscle atrophy after sciatic nerve crush injury in rats
Authors: Gigo‐Benato Davilene , Russo Thiago Luiz , Geuna Stefano , Domingues Natalia Rezende Santa Rosa , Salvini Tania Fátima , Parizotto Nivaldo Antonio
Published: April 2010

Neuromuscular recovery after peripheral nerve lesion depends on the regeneration of severed axons that re‐establish their functional connection with the denervated muscle. The aim of this study was to determine the effects of electrical stimulation (ES) on the neuromuscular recovery after nerve crush injury in rats. Electrical stimulation was carried out on the tibialis anterior (TA) muscle after sciatic nerve crush injury in a rat model. Six ES sessions were administered every other day starting from day 3 postinjury until the end of the experiment (day 14). The sciatic functional index was calculated. Muscle excitability, neural cell adhesion molecule (N‐CAM) expression, and muscle fiber cross‐sectional area (CSA) were accessed from TA muscle. Regenerated sciatic nerves were analyzed by light and confocal microscopy. Both treated (crush+ES) and untreated (crush) groups had their muscle weight and CSA decreased compared with the normal group (P < 0.05). Electrical stimulation accentuated muscle fiber atrophy more in the crush+ES than in the crush group (P < 0.05). N‐CAM expression increased in both crush and crush+ES groups compared with the normal group (P < 0.05). Regenerated nerves revealed no difference between the crush and crush+ES groups. Nevertheless, functional recovery at day 14 post‐injury was significantly lower in crush+ES group compared with the crush group. In addition, the crush+ES group had chronaxie values significantly higher on days 7 and 13 compared with the crush group, which indicates a decrease in muscle excitability in the crush+ES animals. The results of this study do not support a benefit of the tested protocol of ES during the period of motor nerve recovery following injury. Muscle Nerve, 2010
Sonographic evaluation of the sciatic nerve in patients with lower‐limb amputations
Authors: Göktepe A. Salim , Özçakar Levent , Kömürcü Erkam , Safaz İsmail , Yazicioğlu Kamil
Published: April 2010

Hypertrophy of the sciatic nerve after lower‐limb amputation in patients with sarcomas has been previously reported by magnetic resonance imaging; however, sonographic evaluation of the sciatic nerve after lower‐limb amputation due to nonmalignant causes has not been done before. Therefore, the aim of this study was to perform imaging of the sciatic nerve in lower‐limb amputees and to find out whether sonographic findings were related to clinical characteristics. Twenty‐three males with lower‐limb amputations due to traumatic injuries were enrolled. Sonographic evaluations were performed using a linear array probe (Aloka UST‐5524‐7.5 MHZ). Sciatic nerve diameters were measured bilaterally at the same level, and the values of the normal limbs were taken as controls. Sciatic nerve width and thickness values were found to be greater on the amputated sides than the normal sides (P = 0.001). The thickness values were greater in above‐knee amputees than below‐knee amputees (P = 0.05). Subjects with a neuroma also had thicker sciatic nerves (P = 0.04). The diameters were found not to change between subjects with different liners (P > 0.05), but they were correlated with time after amputation (r = 0.6, P = 0.006; r = 0.4, P = 0.05, respectively). Our results clearly show that the sciatic nerves were wider and thicker on the amputated sides. Amputation level, duration, and the presence of a neuroma seem to affect the eventual diameters of the nerves. Muscle Nerve, 2010
Mycophenolate mofetil in AChR‐antibody‐positive myasthenia gravis: Outcomes in 102 patients
Authors: Hehir Michael K. , Burns Ted M. , Alpers Joshua , Conaway Mark R. , Sawa Michael , Sanders Donald B.
Published: April 2010

Two recent randomized, controlled trials failed to demonstrate a benefit of mycophenolate mofetil (MMF) over prednisone in the treatment of myasthenia gravis (MG). We reviewed our experience with MMF in MG to determine whether these trials may have been unsuccessful because of their short duration and the unpredicted benefit of prednisone. We reviewed outcomes and prednisone dosage for all our acetylcholine‐receptor (AChR)‐antibody positive MG patients treated with MMF alone or with prednisone for at least 3 months. The percentage of patients with a desirable outcome (MG‐specific Manual Muscle Test score <4 or Myasthenia Gravis Foundation of America post‐invention status of minimal manifestations or better) began to increase after 6 months; 80% of those followed for >24 months had a desirable outcome. Prednisone dose decreased after 12 months; after 25 months, 54.5% of patients took no prednisone and 75% took <7.5 mg/day. This retrospective analysis provides class IV evidence that MMF begins to improve AChR‐positive MG after 6 months, both with prednisone and as monotherapy. Muscle Nerve 41: 593–598, 2010
Crimson carrier, A long‐acting contrast agent for in vivo near‐infrared imaging of injured and diseased muscle
Authors: Prajapati Suresh I. , Martinez Carlo O. , Abraham Jinu , Mccleish Amanda T. , Michalek Joel E. , McManus Linda M. , Rubin Brian P. , Shireman Paula K. , Keller Charles
Published: April 2010

The near‐infrared wavelengths (700–900 nm) are the most suitable optical window for light penetration and deep tissue imaging in small animals. Herein we report a near‐infrared fluorescent contrast agent, crimson carrier, which acts as a blood pool contrast agent to detect and quantify injury and disease in live animals. After determining the excitation–emission spectra and pharmacokinetics, crimson carrier was injected into myoinjured mice to monitor their recovery. Crimson carrier was also used to image transgenic mice with spontaneous tumors. Crimson carrier has maximal excitation and emission wavelengths of 745 nm and 820 nm, respectively. Elimination occurs predominantly via urinary excretion. We demonstrate the utility of this contrast agent for serial imaging of traumatized muscle as well as muscle tumors. The unique long‐acting pharmacokinetics and urinary excretion route characteristics make crimson carrier a contrast agent of choice for the visualization of tumors and injured muscle or other tissues in live animal studies. Muscle Nerve, 2010
Edward McGuire's influence in the field of stress urinary incontinence and bladder storage symptoms
Authors: Chai Toby C.
Published: April 2010

Aims

Dr. Edward McGuire's academic career spans four decades. His impact in our field of female urology and urodynamics is reflected by the many residents and fellows he has trained that are now academic leaders in our subspecialty. For this festschrift, my goals are to: (1) review the history of the surgical approaches to alleviate stress urinary incontinence (SUI) (2) discuss recent research in SUI and bladder storage symptoms and the influence of Dr. McGuire in these areas and (3) propose a paradigm shift in the understanding of the function of the bladder urothelium from providing barrier function to providing afferent input that affects bladder storage function.

Methods

A literature review of the publications related to SUI and bladder storage symptoms was performed. Using Thompson Reuters ISI Web of Knowledge, the two most cited papers by Dr. McGuire are discussed.

Results

Dr. McGuire's two most cited publications are related to valsalva leak point pressure (VLPP) and the utility of the American Urologic Association Symptom Index (AUASI). These two instruments, one objective and one subjective, address two canonical areas in our subspecialty: 1. role of urethral function in continence and 2. pathophysiology of lower urinary tract symptoms. These two areas continue today to be fertile areas for research and creativity. Recent investigations have proposed that bladder urothelium may play a role in bladder afferent function; thus mediating bladder storage.

Conclusions

Dr. McGuire helped establish the scientific foundation for our subspecialty. His influence remains pertinent today as it ever has. Neurourol. Urodynam. 29:S32–S35, 2010. © 2010 Wiley‐Liss, Inc.
Management of difficult cases in female urology and neurourology at the Reed M. Nesbit society meeting festschrift in honor of Edward J. McGuire, MD
Authors: Blaivas Jerry , McGuire Edward J. , Stöhrer Manfred , Webster George D. , Cameron Anne P.
Published: April 2010

This is a panel discussion of seven complex urologic cases in female urology and neurourology. Differences in diagnosis and management are discussed by this international panel of experts. Neurourol. Urodynam. 29:S2–S12, 2010. © 2010 Wiley‐Liss, Inc.
Vaginal flap urethroplasty for female urethral stricture disease
Authors: Gormley E. Ann
Published: April 2010

Aims

Urethral stricture disease in females is uncommon and is often treated with repeat dilation or internal urethrotomies. Various surgical techniques requiring tissue transfer or grafting to repair strictures have been described with successful results. The vaginal inlay flap is simple and easy to learn. In this follow‐up report of the use of this flap with additional patients more complications with urge symptoms and difficulties with catheterization are reported.

Methods

Twelve symptomatic women with a history of traumatic or difficult catheterization, a history of at least 1 urethral dilation or urethrotomy and difficult or a failed attempt at catheter placement underwent urethroplasty. The technique consisted of incising the posterior aspect of the stricture and advancing a vaginal inlay flap. A retrospective chart review was performed.

Results

Follow‐up was 3 months to 9 years. All patients had subjective relief of most of their symptoms and were able to catheterize with a 14Fr catheter. One patient underwent repeat dilation 3 weeks after the primary procedure with no recurrence and another woman required a cystoscopy and catheter insertion in the OR fifty‐eight months post operatively. No patient had stress urinary incontinence. Irritative symptoms, particularly urge, and difficulties with catheterization persisted in some patients post operatively despite having a technically good repair.

Conclusion

Urethral stricture disease in females is an uncommon entity that can cause voiding symptoms, recurrent infections, retention and renal impairment. This method of surgical repair offers a durable result with a low incidence of complications. Neurourol. Urodynam. 29:S42–S45, 2010. © 2010 Wiley‐Liss, Inc.
Why do women have stress urinary incontinence?
Authors: DeLancey John O.L.
Published: April 2010

This article reviews progress made in understanding the causes of stress urinary incontinence. Over the last century, several hypotheses have been proposed to explain stress urinary incontinence. These theories are based on clinical observations and focus primarily on the causative role of urethral support loss and an open vesical neck. Recently these hypotheses have been tested by comparing measurements of urethral support and function in women with primary stress urinary incontinence to asymptomatic volunteers who were recruited to be similar in age, race, and parity. Maximal urethral closure pressure is the parameter that differs the most between groups being 43% lower in women with stress incontinence than similar asymptomatic women having as effect size of 1.6. Measures of urethral support effect sizes range from 0.5 to 0.6. Because any one objective measure of support may not capture the full picture of urethrovesical mobility, review of blinded ultrasounds of movements during cough were reviewed by an expert panel. The panel was able to identify women with stress incontinence correctly 57% of the time; just 7% above the 50% that would be expected by chance alone, confirming that urethrovesical mobility is not strongly associated with stress incontinence. Although operations that provide differential support to the urethra are effective, urethral support is not the predominant cause of stress incontinence. Improving our understanding of factors affecting urethral closure may lead to novel treatments targeting the urethra and improved understanding of the small but persistent failure rate of current surgery. Neurourol. Urodynam. 29:S13–S17, 2010. © 2010 Wiley‐Liss, Inc.
Effects of different types of polyethylene on the morphology and properties of recycled poly(ethylene terephthalate)/polyethylene compatibilized blends
Authors: Zhang Yue , Zhang Hongsheng , Guo Weihong , Wu Chifei
Published: April 2010

Recycled poly(ethylene terephthalate) (R‐PET) was blended with four types of polyethylene (PE), linear low density polyethylene (LLDPE; LL0209AA, Fs150), low density polyethylene (LDPE; F101‐1), and metallocene‐LLDPE (m‐LLDPE; Fv203) by co‐rotating twin‐screw extruder. Maleic anhydride‐grafted poly(styrene‐ethylene/butyldiene‐styrene) (SEBS‐g‐MA) was added as compatibilizer. R‐PET/PE/SEBS‐g‐MA blends were examined by scanning electron microscopy (SEM), differential scanning calorimeter (DSC), dynamic mechanical analysis (DMA), and mechanical property testing. The results indicated that the morphology and properties of the blends depended to a great extent on the miscibility between the olefin segments of SEBS‐g‐MA and PE. Due to the proper interaction between SEBS‐g‐MA and LDPE (F101‐1), most SEBS‐g‐MA, located at the interface between two phases of PET and LDPE to increase the interfacial adhesion, lead to better mechanical properties of R‐PET/LDPE (F101‐1) blend. However, both the poor miscibility of SEBS‐g‐MA with LLDPE (LL0209AA) and the excessive miscibility of SEBS‐g‐MA with LLDPE (Fs150) and m‐LLDPE (Fv203) reduced the compatibilization effect of SEBS‐g‐MA. DSC results showed that the interaction between SEBS‐g‐MA and PE obviously affected the crystallization of PET and PE. DMA results indicated that PE had more influence on the movement of SEBS‐g‐MA than PE did. Copyright © 2010 John Wiley & Sons, Ltd.
Preparation and characterization of bacterial cellulose/heparin hybrid nanofiber for potential vascular tissue engineering scaffolds
Authors: Wan Yizao , Gao Chuan , Han Ming , Liang Hui , Ren Kaijing , Wang Yulin , Luo Honglin
Published: April 2010

Blending two polymers is a common and effective way to develop a new material with combinations of properties not possessed by individual polymers and to overcome some limitations of individual components. This study aimed at developing a novel scaffold to mimic natural extracellular matrix (ECM) and to promote blood compatibility. Heparin (Hep) and bacterial cellulose (BC), for the first time, were hybridized to prepare a novel class of nanofibrous scaffold for vascular tissue engineering by the co‐synthesis process. The morphology of Hep–BC hybrid nanofiber was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The hybrid was further characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and X‐ray diffraction (XRD). The results show that hybridizing heparin brings anticoagulant sulfate groups into BC nanofiber and that Hep–BC nanofiber has a different structure in comparison to pristine BC. This work paves a new way of improving anticoagulant property of tissue engineered vessels other than coating process. Copyright © 2010 John Wiley & Sons, Ltd.
Glomerular toxicity persists 10 years after ifosfamide treatment in childhood and is not predictable by age or dose
Authors: Skinner Roderick , Parry Annie , Price Lisa , Cole Michael , Craft Alan W. , Pearson Andrew D.J.
Published: April 2010

Background

This prospective longitudinal single institution cohort study evaluated the natural history of and risk factors for chronic nephrotoxicity 10 years after ifosfamide treatment in childhood.

Procedure

Twenty‐five patients (16 males) treated with ifosfamide were investigated at end of treatment (End), 1 and 10 years later. Glomerular filtration rate (GFR), serum phosphate (PO4) and bicarbonate (HCO3) and renal tubular threshold for phosphate (Tmp/GFR) were measured, and total nephrotoxicity score (Ns) graded.

Results

More patients had a low GFR at 1 (72%) and 10 (50%) years than at End (26%) (P = 0.006 for End vs. 1 year). Electrolyte supplementation requirements for tubular toxicity resolved by 10 years (0% vs. 32% at End and 24% at 1 year; both P < 0.05). At 10 years, 17% of patients had moderate overall nephrotoxicity and 13% clinically significant reduction of GFR (<60 ml/min/1.73 m2). Neither dose nor age at treatment predicted any measure of toxicity at 10 years or reduced GFR at any timepoint. Higher cumulative ifosfamide dose correlated with greater tubular and overall nephrotoxicity at End and/or 1 year (P < 0.05 for each of PO4, HCO3, Tmp/GFR, Ns), but age at treatment did not differ between patients with normal or abnormal results.

Conclusions

Although clinically significant tubular toxicity had resolved by 10 years, GFR was <60 ml/min/1.73 m2 in 13% of patients, raising concerns about very long‐term glomerular function. Higher cumulative dose was associated with greater tubular and overall toxicity at End and 1 year, but not at 10 years. Age at treatment did not predict nephrotoxicity at any timepoint. Pediatr Blood Cancer 2010;54:983–989 © 2010 Wiley‐Liss, Inc.
Extended phase I evaluation of vincristine, irinotecan, temozolomide, and antibiotic in children with refractory solid tumors
Authors: McNall‐Knapp René Y. , Williams Cydni N. , Reeves Elaine N. , Heideman Richard L. , Meyer William H.
Published: April 2010

Background

The combination of irinotecan, temozolomide, and vincristine is appealing because of potentially synergistic mechanisms of action and non‐overlapping toxicities. This phase I study was designed to determine the toxicity and maximum tolerated dose (MTD) of escalating daily protracted doses of irinotecan given in this combination. With extended accrual, we more fully explored the toxicity of multiple courses at the MTD.

Procedure

Patients under 22 years with recurrent or refractory solid tumors were eligible. A course of chemotherapy was given every 28 days. Cefpodoxime was given for diarrhea prophylaxis. Vincristine (1.5 mg/m2, max 2 mg) was given intravenously (IV) on days 1 and 8. Temozolomide (100 mg/m2/day) was given orally on days 1–5. Irinotecan was given IV over 1 hr on days 1–5 and 8–12. Dose escalation was done in the standard 3 + 3 cohort design, starting at 15 mg/m2/day.

Results

Twenty‐five of 26 eligible patients were evaluable for toxicity and response. They received 111 courses (1–13, median 4). Dose limiting toxicity (DLT—pancreatitis, transaminitis) was seen in two of three patients at dose level 2 (20 mg/m2). No patients at level 1 had DLT during the first two cycles. Thus, the MTD of irinotecan in this combination is 15 mg/m2/day × 10 doses. Hematologic toxicity was mild and not prolonged. Grade 3 diarrhea was seen in five courses. Responses included two complete and two partial with 12 stable disease (SD) (median 6 months).

Conclusions

This combination is safe and shows activity in pediatric patients with recurrent malignancy. Pediatr Blood Cancer 2010;54:909–915 © 2010 Wiley‐Liss, Inc.
Myeloid leukaemia in children with down syndrome: Report of the registry‐based French experience between 1990 and 2003
Authors: Tandonnet Julie , Clavel Jacqueline , Baruchel André , Nacka Fabienne , Pérel Yves
Published: April 2010

Aim

To determine the epidemiology of myeloid leukaemia (ML) in children with Down syndrome (DS) and the efficacy of two approaches, low‐dose cytarabine‐based regimen (LDC) and standard‐dose intensive chemotherapy (SD).

Procedure

All children with Down syndrome aged from 2 months to 15 years with ML/myelodysplasia registered in the French registry between January 1990 and December 2003 were included.

Results

Forty‐four patients were included. The median age was 1.75 years. The French–America–British subtypes were as follows: M7: 24, M0: 6, M2: 5, M6: 2. Forty‐three patients were treated with curative prospect, 20 patients with LDC regimen and 22 according to SD protocols, 1 was given the LDC regimen plus autologous stem‐cell transplantation. The event‐free survival (EFS) and overall survival (OS) at 5 years were 64.4% and 76.8%. At 5 years, OS in LDC and SD groups were 65% and 85.9% (P = 0.08). EFS were 45% and 80.3% respectively (P < 0.01).

Conclusion

Children with DS can adequately tolerate SD chemotherapy with a significant superiority of EFS relative to LDC. We suggest that higher levels of cure can be obtained in DS‐ML with SD chemotherapy including cytarabine and anthracyclines. Pediatr Blood Cancer 2010;54:927–933 © 2010 Wiley‐Liss, Inc.
Differential expression of protease activity in serum samples of prostate carcinoma patients with metastases
Authors: Dekker Lennard J. M. , Burgers Peter C. , Charif Halima , van Rijswijk Angelique L. C. T. , Titulaer Mark K. , Jenster Guido , Bischoff Rainer , Bangma Chris H. , Luider Theo M.
Published: April 2010

We present here the results from MS peptide profiling experiments of prostate carcinoma patients and controls with a specific focus on protease activity‐related protein fragments. After purification with surface‐active magnetic beads, MALDI‐TOF profiling experiments were performed on tryptic digests of serum samples of prostate cancer patients with metastases (n=27) and controls (n=30). This resulted in the reproducible detection of eight differentially expressed peptides, which were then identified by nanoLC‐MALDI‐TOF/TOF and confirmed by MALDI‐FTMS exact mass measurements. All differentially expressed peptides are derived from two homologous parts of human serum albumin; two of the eight peptides were tryptic and six were nontryptic. The presence of the nontryptic fragments indicates that a proteolysis process occurs which is not mediated by trypsin. Since the nontryptic fragments were found at significantly higher levels in control samples compared with metastases samples, it is proposed that a specific proteolytic inhibition process is in effect in the serum of prostate cancer patients. Experiments using synthetic peptides showed that this proteolytic activity occurs ex vivo and is sequence specific. Importantly, the observed prostate carcinoma‐related inhibition of the proteolysis was reproduced ex vivo using synthetic peptides.
Comparative proteome analysis of metabolic proteins from seeds of durum wheat (cv. Svevo) subjected to heat stress
Authors: Laino Paolo , Shelton Dale , Finnie Christine , De Leonardis Anna Maria , Mastrangelo Anna Maria , Svensson Birte , Lafiandra Domenico , Masci Stefania
Published: April 2010

In Central and Southern Italy, where durum wheat represents one of the most widely cultivated crops, grain filling occurs during Spring, a period characterized by sudden increases in temperature. Wheat grain proteins are classified into albumins, globulins, and prolamins. The nonprolamin fractions include proteins with metabolic activity or structural function. In order to investigate the consequences of heat stress on the accumulation of nonprolamin proteins in mature durum wheat kernels, the Italian cultivar Svevo was subjected to two thermal regimes (heat stress versus control). The 2‐D patterns of nonprolamin proteins were monitored to identify polypeptides affected by heat stress during grain fill. This study shows that heat stress alters significantly the durum wheat seed proteome, although the changes range is only between 1.2‐ and 2.2‐fold. This analysis revealed 132 differentially expressed polypeptides, 47 of which were identified by MALDI‐TOF and MALDI‐TOF‐TOF MS and included HSPs, proteins involved in the glycolysis and carbohydrate metabolism, as well as stress‐related proteins. Many of the heat‐induced polypeptides are considered to be allergenic for sensitive individuals.
Conformational pathways of simple six‐membered rings
Authors: Stortz Carlos A.
Published: April 2010

The conformational equilibria of cyclohexane (as well as its fluoro‐, chloro‐, methyl‐, hydroxy‐, and t‐butyl derivatives), cyclohexanone, piperidine, tetrahydropyran (and its 2‐hydroxy derivative) were studied by ab initio and DFT procedures. The transition states were calculated at HF/6‐31G, B3LYP/6‐31+G*, and B3LYP/6‐311+G** levels, whereas the intrinsic reaction coordinates (IRCs) were evaluated at the B3LYP/6‐31+G* level. The degree of puckering and energy data was nearly not basis set‐dependent (using B3LYP) in most of the cases. However, DFT methods gave better agreement with experimental data than HF methods, as expected from electron correlation inclusion. Fluorocyclohexane and 2‐hydroxytetrahydropyran showed the largest basis set‐energy dependence. It was found that the conversion from chair to skew is direct in some cases, whereas in others it goes through the pseudorotational (skew/boat) pathway. The case of t‐butylcyclohexane, with a skew form as stable as one of the chairs, is especially interesting. In this compound, as well as in cyclohexanone and 2‐hydroxytetrahydropyran, large deviations from the known pseudorotation/inversion scheme are observed. Copyright © 2010 John Wiley & Sons, Ltd.
Proton coupled electron transfer reaction of phenols with excited state ruthenium(II) – polypyridyl complexes
Authors: Swarnalatha K. , Rajkumar E. , Rajagopal S. , Ramaraj R. , Banu I. Sadhiya , Ramamurthy P.
Published: April 2010

The reaction of phenols with the excited state, *[Ru(bpy)3]2+ (E0 = 0.76 V) and *[Ru(H2dcbpy)3]2+, (dcbpy = 4,4′‐dicarboxy‐2,2′‐bipyridine) (E0 = 1.55 V vs. SCE) complexes in CH3CN has been studied by luminescence quenching technique and the quenching is dynamic. The formation of phenoxyl radical as a transient is confirmed by its characteristic absorption at 400 nm. The kq value is highly sensitive to the change of pH of the medium and ΔG0 of the reaction. Based on the treatment of kq data in terms of energetics of the reaction and pH of the medium, proton coupled electron transfer (PCET) mechanism has been proposed for the reaction. Copyright © 2010 John Wiley & Sons, Ltd.
Relationships between functional subclasses and information contained in active‐site and ligand‐binding residues in diverse superfamilies
Authors: Nagao Chioko , Nagano Nozomi , Mizuguchi Kenji
Published: April 2010

To investigate the relationships between functional subclasses and sequence and structural information contained in the active‐site and ligand‐binding residues (LBRs), we performed a detailed analysis of seven diverse enzyme superfamilies: aldolase class I, TIM‐barrel glycosidases, α/β‐hydrolases, P‐loop containing nucleotide triphosphate hydrolases, collagenase, Zn peptidases, and glutamine phosphoribosylpyrophosphate, subunit 1, domain 1. These homologous superfamilies, as defined in CATH, were selected from the enzyme catalytic‐mechanism database. We defined active‐site and LBRs based solely on the literature information and complex structures in the Protein Data Bank. From a structure‐based multiple sequence alignment for each CATH homologous superfamily, we extracted subsequences consisting of the aligned positions that were used as an active‐site or a ligand‐binding site by at least one sequence. Using both the subsequences and full‐length alignments, we performed cluster analysis with three sequence distance measures. We showed that the cluster analysis using the subsequences was able to detect functional subclasses more accurately than the clustering using the full‐length alignments. The subsequences determined by only the literature information and complex structures, thus, had sufficient information to detect the functional subclasses. Detailed examination of the clustering results provided new insights into the mechanism of functional diversification for these superfamilies. Proteins 2010. © 2010 Wiley‐Liss, Inc.
Diterpene cyclases and the nature of the isoprene fold
Authors: Cao Rong , Zhang Yonghui , Mann Francis M. , Huang Cancan , Mukkamala Dushyant , Hudock Michael P. , Mead Matthew E. , Prisic Sladjana , Wang Ke , Lin Fu‐Yang , Chang Ting‐Kai , Peters Reuben J. , Oldfield Eric
Published: April 2010

The structures and mechanism of action of many terpene cyclases are known, but no structures of diterpene cyclases have yet been reported. Here, we propose structural models based on bioinformatics, site‐directed mutagenesis, domain swapping, enzyme inhibition, and spectroscopy that help explain the nature of diterpene cyclase structure, function, and evolution. Bacterial diterpene cyclases contain ∼20 α‐helices and the same conserved “QW” and DxDD motifs as in triterpene cyclases, indicating the presence of a βγ barrel structure. Plant diterpene cyclases have a similar catalytic motif and βγ‐domain structure together with a third, α‐domain, forming an αβγ structure, and in H+‐initiated cyclases, there is an EDxxD‐like Mg2+/diphosphate binding motif located in the γ‐domain. The results support a new view of terpene cyclase structure and function and suggest evolution from ancient (βγ) bacterial triterpene cyclases to (βγ) bacterial and thence to (αβγ) plant diterpene cyclases. Proteins 2010. © 2010 Wiley‐Liss, Inc.
English field samples of Thrips tabaci show strong and ubiquitous resistance to deltamethrin
Authors: Foster Stephen P , Gorman Kevin , Denholm Ian
Published: April 2010

BACKGROUND: Onion thrips, Thrips tabaci Lindeman, is a prevalent pest of glasshouse and field vegetables, such as leeks and salad onions. Pesticides are the main option for control, but this approach risks the evolution and spread of insecticide resistance. In the light of anecdotal reports in the United Kingdom of poor efficacy of pyrethroids against T. tabaci, thought to be primarily a consequence of resistance, the responses to deltamethrin of ten English samples of T. tabaci, collected from field leeks and salad onions in 2006, were measured to establish the level and prevalence of potential resistance to this compound.

RESULTS: All the samples showed significant deltamethrin resistance that was comparable or slightly lower than the maximum level reported previously for T. tabaci from New Zealand.

CONCLUSION: The mechanism(s) conferring deltamethrin resistance remain unknown at present but are likely to extend to other synthetic pyrethroids approved for use against this species. The findings suggest that these compounds are unlikely to give satisfactory control of T. tabaci in England and have stimulated the recommendation to use alternatives. Copyright © 2010 Society of Chemical Industry
Spin properties of trions in a dense 2DEG
Authors: Kochereshko V. , Besombes L. , Mariette H. , Wojtowicz T. , Karczewski G. , Kossut J.
Published: April 2010

Reflectivity and photoluminescence spectra from CdTe/CdMgTe modulation‐doped quantum well structures were studied. We have found that in reflectivity spectra the value and the sign of the Zeeman splitting of the trion lines depend on the electron concentration in the quantum well, whereas, the value and sign of the exciton line splitting are constant for all studied electron concentrations. On the other hand, in the photoluminescence spectra the sign and value of the Zeeman splitting are the same for trion and exciton. Such “renormalization” of the trion g‐factor is explained in the model of combined exciton–electron processes.
Excitonic polaritons in transverse magnetic fields
Authors: Loginov D.K. , Kochereshko V.P. , Cox R.T. , Besombes L. , Mariette H. , Davies J.J. , Wolverson D. , Smith L.C.
Published: April 2010

Exciton‐polariton reflectivity of wide CdTe/CdZnTe quantum‐wells (with well widths exceeding by far the exciton Bohr radius) was measured in the Voigt geometry in a magnetic field. In a magnetic field, forbidden exciton lines were observed to appear for each exciton quantization level. The exciton diamagnetic shift constant was observed to decrease noticeably with increasing quantum number of the confined level. A comparison of calculated with experimental spectra reveals a growth of the exciton translational mass with increasing magnetic field. It has been shown that both the growth of mass and the decrease of the diamagnetic shift can be traced to mixing between exciton internal and translational motion states.
Determination of the band‐gap of MgS and MgS‐rich Zn1−xMgxSySe1−y alloys from optical transmission measurements
Authors: Davidson Ian A. , Moug Richard T. , Izdebski Frauke , Bradford Christine , Prior Kevin A.
Published: April 2010

As part of our development of an epitaxial lift‐off process, utilising a sacrificial magnesium sulphide (MgS) layer, we have developed a MgS‐rich ZnMgSSe alloy which provides excellent carrier confinement and resists both oxidation and acid attack. Here the optical transmission of the alloy has been measured and its bandgap determined as a direct transition at 4.19 ± 0.04 eV. Its composition has also been determined by X‐ray interference (XRI) and comparison with simulations. For a range of alloy samples we obtain compositions of the Zn1−xMgxSySe1−y layers which are (x, y) = (0.80 ± 0.02, 0.645 ± 0.025). Using the alloy bandgap and composition we have determined direct bandgap transition energy for MgS by extrapolation. This is found to be 4.78 ± 0.14 eV.
Clustering in a self‐assembled CdTe/ZnTe quantum dot plane revealed by inter‐dot coupling
Authors: Kazimierczuk T. , Golnik A. , Wojnar P. , Gaj J. A. , Kossacki P.
Published: April 2010

We study probability of coupling between randomly distributed quantum dots (QDs) in self‐assembled CdTe/ZnTe heterostructures grown with different thicknesses of CdTe formation layer. Photoluminescence excitation spectra reveal a number of QD pairs involved in inter‐dot energy transfer. The statistics of dot pairs was collected at numerous spots of samples. It shows that the observed coupling is more frequent than that expected for a uniform random distribution of QDs.
Exciton magnetic polaron in CdMnSe/CdMgSe quantum wells
Authors: Godde T. , Reshina I.I. , Ivanov S.V. , Akimov I.A. , Yakovlev D.R. , Bayer M.
Published: April 2010

We study exciton magnetic polaron (EMP) formation in (Cd,Mn)Se/(Cd,Mg)Se diluted magnetic semiconductor quantum wells (QWs) using time‐resolved photoluminescence (PL). Magnetic field dependence of the transients allows us to separate the non‐magnetic and magnetic contributions of the exciton localization. We find binding energy of 18 meV and formation time of 500 ps for the EMP. We propose that long polaron formation time is related to auto‐localization process, accompanied with the squeezing of the heavy‐hole envelope wave function. This conclusion is supported by a strong reduction of the exciton radiative lifetime from 600  to 200 ps with increase of magnetic field.
Sub‐ns electrical control of spin polarization in a semiconductor by microscale current loops
Authors: Chen Y. S. , Wiater M. , Karczewski G. , Wojtowicz T. , Bacher G.
Published: April 2010

We demonstrate a method to electrically control the spin polarization in a diluted magnetic semiconductor (DMS) quantum well (QW) on a micrometer length scale. A variable magnetic field generated from a microscale current loop atop a single CdMnTe/CdMgTe QW magnetizes the Mn2+ ion spins in the DMS QW and, via the sp–d exchange interaction, polarizes the spins of photon‐generated carriers. In the absence of an external field, the spin polarization can be switched on a time scale clearly below 1 ns.
Structural and optical properties of ZnSe‐based diluted magnetic semiconductor quantum‐well wire arrays by wet chemical etching
Authors: Muranaka Tsutomu , Iizuka Suguru , Hishikawa Masao , Kodama Kazuki , Ohmori Kenta , Nabetani Yoichi , Matsumoto Takashi
Published: April 2010

The ZnSe‐based mesa structures with well‐defined and smooth facets were successfully demonstrated by using molecular beam epitaxy (MBE) and wet chemical etching. The ZnSe structures were found to be bound by (111) and (‐1‐11) facets along the [‐110] direction, and bound by (1‐11) and (‐111) facets along the [110] direction, respectively. The intensities of the non‐polarized PL peaks from the [‐110]‐ and [110]‐oriented QWW structures were almost proportional to the unetched region and additional decreases were not observed. The PL peaks from the QWW structures were found to be highly polarized when the polarization angle was aligned parallel to the wire direction. The degrees of the linear polarization were 18% for the [‐110]‐oriented QWW structure and 26% for the [‐110]‐oriented QWW structure, respectively. The results of the PL and magneto‐PL measurements show no process‐induced damage to degrade magneto‐optical performance of the DMS structures by using this method. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nanocrystalline Ni3Al‐based alloys produced by mechanical alloying of Ni‐Al‐Co powders and consolidation
Authors: Antolak‐Dudka Anna , Krasnowski Marek , Kulik Tadeusz
Published: April 2010

In this work, preparation of nanocrystalline Ni3Al‐based alloys by mechanical alloying process followed by hot‐pressing consolidation is reported. Ni75Al20Co5 and Ni70Al25Co5 elemental powder mixtures were subjected to ball milling. Subsequently, the milling products were sintered at 1000 °C under a pressure of 7.7 GPa. The powders and the consolidated pellets were investigated by X‐ray diffraction. The results obtained show that the milling products were in both cases supersaturated solid solutions Ni(Al,Co) and that during the hot‐pressing consolidation they had transformed into nanocrystalline Ni3Al‐based intermetallic compounds. The microhardness of the produced Ni3Al‐based alloys is 918 HV0.1 in the case of Ni75Al20Co5 composition and 1033 HV0.1 in the second case. The density of compacted materials is close to the theoretical value and their open porosity is negligible. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tailoring mechanical properties of nano‐structured Eurofer 97 steel for fusion applications
Authors: Kozikowski Paweł M. , Krawczyńska Agnieszka T. , Kulczyk Mariusz , Lewandowska Małgorzata , Kurzydłowski Krzysztof J.
Published: April 2010

EUROFER 97 steel is a candidate structural material for future fusion reactors and Test Blanket Modules (TBMs). In the present work microstructure of Eurofer 97 was modified by hydrostatic extrusion in multi‐step process with total true strain exceeding 3. TEM observations showed that HE causes significant grain refinement from about 400 to 80 nm. This is accompanied by improvement of the tensile mechanical properties and microhardness. On the other hand, there is a clear decrease in the resistance to brittle fracture as measured in the Charpy impact tests. In order to improve strength/ductility/fracture toughness balance, the extruded samples were annealed for 1 hour at temperature range of 473‐1073K. The results obtained for samples after post‐extrusion annealing are discussed in terms of mechanical properties of Eurofer 97 steel. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of deformation and strain rate on the microstructure refinement of the aluminium alloys (AlCu4Zr0.5 and AlZn6Mg3CuZr)
Authors: Leszczyńska‐Madej Beata , Richert Maria , Kurzydłowski Krzysztof J. , Pachla Wacław
Published: April 2010

The well known refinement of grain size by the Severe Plastic Deformation (SPD) methods is the subject of the presented work. The effect of intense deformation is a nanometric feature of microstructure found after SPD in various materials, such as aluminium alloys, iron and many others. The observed changes depended on the properties of the deformed material, its phase composition, stacking fault energy, degree of deformation, strain rate, etc. Nowadays, the influence of strain and strain rate on microstructure is being extensively investigated. Two aluminium alloys: AlCu4Zr0.5 and AlZn6Mg3CuZr were deformed by hydrostatic extrusion. The samples were deformed at a strain rate (έ) ranging from 7.4×101 to 3.84×102s‐1 and in the range of true strains (ϕ) between 1.39 and 2.4. The evolution of microstructure and properties were investigated after deformation. A large amount of microbands and microshearbands was found in the tested samples. The microbands geometry (width of microbands) was analysed statistically and microhardness was measured. It has been found that the microbands show a large misorientation with respect to the matrix. An increase in the strain rate and degree of deformation resulted in a reduction in the microbands width in AlZn6Mg3CuZr alloy. In both alloys the mean width of microbands (d) fell into the range 100÷120 nm after deformation ϕ = 2.4 (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of the phase composition of Fe2O3 and Fe2O3/TiO2 nanoparticles using X‐ray diffraction and Debye formula
Authors: Valeš Václav , Poltierová‐Vejpravová Jana , Holý Václav , Tyrpekl Václav , Brázda Petr , Doyle Stephen
Published: April 2010

Phase changes in Fe2O3 and Fe2O3/TiO2 nanoparticles were studied by X‐ray diffraction. Because of a very small size of the particles, standard methods of data analysis based on the physical broadening of lines and instrumental function fail and calculations based on the Debye formula were used instead. The measured data from both types of particles were analyzed assuming a core‐shell model of the phase composition of the particles and the dependence of the particle size and phase composition on the annealing temperature was determined. In both types of nanoparticles a phase transition was observed and the amount of a new phase increases with the annealing temperature. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of nanocrystalline Ni layers electrodeposited in Watts bath with addition of C4Br ionic liquids
Authors: Moszczyński Piotr , Trzaska Maria
Published: April 2010

The influence of different contents of the C4Br (Butyl‐(‐2‐hydroxyethyl)‐dimethylammonium Bromide) ionic liquid into Watts bath with saccharine addition on properties of nanocrystalline Ni surface layers is investigated. The structural analyses of prepared layers were performed by using the X‐ray diffraction measurement and transmission electron microscopy. The mean crystalline size of nc‐Ni layers was reduced from 14 to 7 nm by the different contents of ionic liquid addition to the electrolyte. The morphology and topography of produced layers were investigated by scanning electron microscopy. The higher additions of C4Br in the bath have involved nodular structures of plating nickel surface layers. Results determined by Vickers tests of prepared layers have shown much larger hardness of layers prepared in modified bath in comparison to basic bath. The hardness (HV) was increased from 600 to 1130 by the addition of 1.2 g/dm3C4Br to the bath. Results of performed investigations have showed that the introduction of ionic liquids into bath leads to important improvements of mechanical properties of the nanocrystalline Ni surface layers produced by the electrodeposition method. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of suspended fully metallic ultra‐small capacitance nano‐junctions
Authors: Kim Chulki , Kim Hyun S. , Park Jonghoo , Blick Robert H.
Published: April 2010

We demonstrate the fabrication of freely suspended metallic islands using an SF6 etching and deposition technique. The resulting structure consists of nanoscale islands connected to source and drain contacts by thin CF2 layers. This enables operation of the suspended island as a coupled metal–insulator–metal (MIM) junction with application as ultra‐sensitive nano‐diodes. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)