Investigation of ion induced bending mechanism for nanostructures

Ion induced bending is a promising controlled technique for manipulating nanoscale structures. However, the underlying mechanism of the process is not well understood. In this letter, we report a detailed study of the bending mechanism of Si nanowires (NWs) under Ga+ irradiation. The microstructural changes in the NW due to ion beam irradiation are studied and molecular dynamics simulations are used to explore the ion–NW interaction processes. The simulation results are compared with the microstructural studies of the NW. The investigations inform a generic understanding of the bending process in crystalline materials, which we suggest to be feasible as a versatile manipulation and integration technique in nanotechnology

Rapid and Sensitive Detection of Yersinia pestis Using Amplification of Plague Diagnostic Bacteriophages Monitored by Real-Time PCR

BACKGROUND: Yersinia pestis, the agent of plague, has caused many millions of human deaths and still poses a serious threat to global public health. Timely and reliable detection of such a dangerous pathogen is of critical importance. Lysis by specific bacteriophages remains an essential method of Y. pestis detection and plague diagnostics. METHODOLOGY/PRINCIPAL FINDINGS: The objective of this work was to develop an alternative to conventional phage lysis tests--a rapid and highly sensitive method of indirect detection of live Y. pestis cells based on quantitative real-time PCR (qPCR) monitoring of amplification of reporter Y. pestis-specific bacteriophages. Plague diagnostic phages phiA1122 and L-413C were shown to be highly effective diagnostic tools for the detection and identification of Y. pestis by using qPCR with primers specific for phage DNA. The template DNA extraction step that usually precedes qPCR was omitted. phiA1122-specific qPCR enabled the detection of an initial bacterial concentration of 10(3) CFU/ml (equivalent to as few as one Y. pestis cell per 1-microl sample) in four hours. L-413C-mediated detection of Y. pestis was less sensitive (up to 100 bacteria per sample) but more specific, and thus we propose parallel qPCR for the two phages as a rapid and reliable method of Y. pestis identification. Importantly, phiA1122 propagated in simulated clinical blood specimens containing EDTA and its titer rise was detected by both a standard plating test and qPCR. CONCLUSIONS/SIGNIFICANCE: Thus, we developed a novel assay for detection and identification of Y. pestis using amplification of specific phages monitored by qPCR. The method is simple, rapid, highly sensitive, and specific and allows the detection of only live bacteria

Heart Valve Tissue Engineering: Concepts, Approaches, Progress, and Challenges

Potential applications of tissue engineering in regenerative medicine range from structural tissues to organs with complex function. This review focuses on the engineering of heart valve tissue, a goal which involves a unique combination of biological, engineering, and technological hurdles. We emphasize basic concepts, approaches and methods, progress made, and remaining challenges. To provide a framework for understanding the enabling scientific principles, we first examine the elements and features of normal heart valve functional structure, biomechanics, development, maturation, remodeling, and response to injury. Following a discussion of the fundamental principles of tissue engineering applicable to heart valves, we examine three approaches to achieving the goal of an engineered tissue heart valve: (1) cell seeding of biodegradable synthetic scaffolds, (2) cell seeding of processed tissue scaffolds, and (3) in-vivo repopulation by circulating endogenous cells of implanted substrates without prior in-vitro cell seeding. Lastly, we analyze challenges to the field and suggest future directions for both preclinical and translational (clinical) studies that will be needed to address key regulatory issues for safety and efficacy of the application of tissue engineering and regenerative approaches to heart valves. Although modest progress has been made toward the goal of a clinically useful tissue engineered heart valve, further success and ultimate human benefit will be dependent upon advances in biodegradable polymers and other scaffolds, cellular manipulation, strategies for rebuilding the extracellular matrix, and techniques to characterize and potentially non-invasively assess the speed and quality of tissue healing and remodeling

Surgical Management of Sirenomelia: A Case Study

Background: Sirenomelia is a rare congenital condition characterized by fusion of the lower limbs. Patients with sirenomelia generally do not survive long after birth because the condition is associated with multisystem organ dysfunction due to developmental anomalies. Considering the low incidence and few cases surviving the neonatal period, there is minimal understanding regarding the surgical management of sirenomelia. We present a unique case of an infant born with type 1 sirenomelia, absence of external genitalia, presence of a cloaca, absence of the bladder, and presence of an imperforate and vestigial anus, who not only survived the birth process, but, at the age of 11 months, was determined to be a candidate for surgical separation of the lower extremities. Methods: This case was approached much like a dorsal rectangular flap syndactyly release. Large Z-plasty flaps were designed and raised, and the soft tissue within the skin bridge was meticulously dissected to preserve anatomy and to provide adequate skin flaps without perineal skin grafting. A quadrangular flap was designed to reconstruct the perineum and produce a neo-vulva using de-epithelialization. Results: Successful lower extremity separation was achieved. There were no major postoperative complications. The patient progressed with lower extremity function, and eventually achieved independent ambulation. Conclusions: Management of sirenomelia is incredibly challenging, and data to guide surgical management are limited. This report details our approach to a successful lower extremity separation, repair, and neo-vulvar reconstruction in a case of type I sirenomelia

Outcomes after Anterior Interosseous Nerve to Ulnar Motor Nerve Transfer

Background: Ulnar nerve lesions proximal to the elbow can result in loss of intrinsic muscle function of the hand. The anterior interosseous nerve (AIN) to deep motor branch of the ulnar nerve (DBUN) transfer has been demonstrated to provide intrinsic muscle reinnervation, thereby preventing clawing and improving pinch and grip strength. The purpose of this study was to evaluate the efficacy of the AIN to DBUN transfer in restoring intrinsic muscle function for patients with traumatic ulnar nerve lesions. Methods: We performed a prospective, multi-institutional study of outcomes following AIN to DBUN transfer for high ulnar nerve injuries. Twelve patients were identified, nine of which were enrolled in the study. The mean time from injury to surgery was 15 weeks. Results: At final follow-up (mean postoperative follow-up 18 months + 15.5), clawing was observed in all nine patients with metacarpophalangeal joint hyperextension of the ring finger averaging 8.9 degrees (+ 10.8) and small finger averaging 14.6 degrees (+ 12.5). Grip strength of the affected hand was 27% of the unaffected extremity. Pinch strength of the affected hand was 29% of the unaffected extremity. None of our patients experienced claw prevention after either end-to-end ( n  = 4) or end-to-side ( n  = 5) AIN to DBUN transfer. Conclusion: We conclude that, in traumatic high ulnar nerve injuries, the AIN to DBUN transfer does not provide adequate intrinsic muscle reinnervation to prevent clawing and normalize grip and pinch strength

Supraclavicular Approach to the Brachial Plexus

Background: The brachial plexus consists of an intricate array of nerves originating from the C5–T1 ventral rami of the spinal cord. Their course is complex and can be substantially distorted after injury. Thus, dissection of the brachial plexus can be difficult. Here, we present a practical approach to the supraclavicular dissection of the brachial plexus, with emphasis on relevant anatomy and surgical landmarks. Methods: This anatomical review was prepared using intraoperative surgical imaging. In addition, illustrations are used to display the images in schematic form. We present a stepwise surgical approach to the supraclavicular dissection of the brachial plexus. We highlight the differences between pre- and postganglionic nerve root injuries, and also relevant anatomical variants of the brachial plexus. Results: Eleven steps are recommended to facilitate the supraclavicular approach to the brachial plexus. Conclusion: The supraclavicular dissection of the brachial plexus is reliable with consistent landmarks and can be carried out in a stepwise fashion

Enhancement of Facial Nerve Motoneuron Regeneration through Cross-Face Nerve Grafts by Adding End-to-Side Sensory Axons

Background: In unilateral facial palsy, cross-face nerve grafts are used for emotional facial reanimation. Facial nerve regeneration through the grafts takes several months, and the functional results are sometimes inadequate. Chronic denervation of the cross-face nerve graft results in incomplete nerve regeneration. The authors hypothesize that donor axons from regional sensory nerves will enhance facial motoneuron regeneration, improve axon regeneration, and improve the amplitude of facial muscle movement. Methods: In the rat model, a 30-mm nerve graft (right common peroneal nerve) was used as a cross-face nerve graft. The graft was coapted to the proximal stump of the transected right buccal branch of the facial nerve and the distal stumps of the transected left buccal and marginal mandibular branches. In one group, sensory occipital nerves were coapted end-to-side to the cross-face nerve graft. Regeneration of green fluorescent protein-positive axons was imaged in vivo in transgenic Thy1-green fluorescent protein rats, in which all neurons express green fluorescence. After 16 weeks, retrograde labeling of regenerated neurons and histomorphometric analysis of myelinated axons was performed. Functional outcomes were assessed with video analysis of whisker motion. Results: Pathway protection with sensory axons significantly enhanced motoneuron regeneration, as assessed by retrograde labeling, in vivo fluorescence imaging, and histomorphometry, and significantly improved whisker motion during video analysis. Conclusion: Sensory pathway protection of cross-face nerve grafts counteracts chronic denervation in nerve grafts and improves regeneration and functional outcomes

High-Sensitivity Cardiac Troponin I Levels and Prediction of Heart Failure: Results From the BiomarCaRE Consortium

Objectives: The aims of this study were to characterize the association of high-sensitivity cardiac troponin I (hs-cTnI) with heart failure (HF), to determine its predictive value beyond classical cardiovascular risk factors (CVRFs) and N-terminal pro\u2013B-type natriuretic peptide, and to derive a relevant cutoff for potential clinical application. Background: HF is an important contributor to the overall burden of cardiovascular disease. Early identification of individuals at risk could be beneficial for preventive therapies. Methods: Based on the Biomarker for Cardiovascular Risk Assessment in Europe consortium, we analyzed individual-level data from 4 prospective population-based cohort studies including 48,455 individuals. Participants with myocardial infarction, HF, and stroke at baseline were excluded. We investigated the value of adding hs-cTnI to CVRFs and N-terminal pro\u2013B-type natriuretic peptide using Cox proportional hazards survival models and for prediction by calculating C-statistics and Brier score. Results: The median age of the study population was 51 years, and the median follow-up time for occurrence of HF was 6.61 years. Cox regression models adjusted for age, sex, and CVRFs revealed a significant association of hs-cTnI with incident HF (hazard ratio: 1.42 per log [ng/l] unit change [95% confidence interval: 1.31 to 1.53]). The best predictive value was achieved in the model with CVRFs (base model) and both biomarkers (C-index = 0.862; 95% confidence interval: 0.841 to 0.882). Optimal hs-cTnI cutoff values of 2.6 ng/l for women and 4.2 ng/l for men were derived for selecting individuals at risk. Conclusions: In this large dataset from the general population, hs-cTnI could show its independence for the prognosis of HF

Worldwide Testing of the eFACE Facial Nerve Clinician-Graded Scale

Item does not contain fulltextBACKGROUND: The electronic, clinician-graded facial function scale (eFACE) is a potentially useful tool for assessing facial function. Beneficial features include its digital nature, use of visual analogue scales, and provision of graphic outputs and scores. The authors introduced the instrument to experienced facial nerve clinicians for feedback, and examined the effect of viewing a video tutorial on score agreement. METHODS: Videos of 30 patients with facial palsy were embedded in an Apple eFACE application. Facial nerve clinicians were invited to perform eFACE video rating and tutorial observation. Participants downloaded the application, viewed the clips, and applied the scoring. They then viewed the tutorial and rescored the clips. Analysis of mean, standard deviation, and confidence interval were performed. Values were compared before and after tutorial viewing, and against scores obtained by an experienced eFACE user. RESULTS: eFACE feedback was positive; participants reported eagerness to apply the instrument in clinical practice. Standard deviation decreased significantly in only two of the 16 categories after tutorial viewing. Subscores for static, dynamic, and synkinesis all demonstrated stable standard deviations, suggesting that the instrument is intuitive. Participants achieved posttutorial scores closer to the experienced eFACE user in 14 of 16 scores, although only a single score, nasolabial fold orientation with smiling, achieved statistically significant improvement. CONCLUSIONS: The eFACE may be a suitable, cross-platform, digital instrument for facial function assessment, and was well received by facial nerve experts. Tutorial viewing does not appear to be necessary to achieve agreement, although it does mildly improve agreement between occasional and frequent eFACE users