bluuebunny/crossref_metadata_2025_split huggingface dataset:
Foot Center of Pressure Trajectory Alteration by Biomechanical Manipulation of Shoe Design
Authors: Khoury Mona , Wolf Alon , Debbi Eytan M. , Herman Amir , Haim Amir 
Published: March 2013

Background: Footwear-generated biomechanical manipulations have been shown to alter lower limb kinetics. It has been suggested that this is due to altered trajectory of the foot’s center of pressure (COP), conveying a shift in location of the ground reaction force and modifying moments and forces acting on proximal body segments. However, past studies have focused on qualitative association between footwear design and the COP locus. Moreover, this association was calculated via indirect analysis. The purpose of the present study was to directly examine and quantify the correlation between measured footwear biomechanical manipulation and the location of the COP trajectory during gait. Methods: A novel biomechanical device allowing flexible positioning of 2 convex-shaped elements attached to its sole was utilized. A total of 20 healthy male adults underwent direct in-shoe pressure measurements while walking with the device set at 7 mediolateral configurations. COP data were collected during gait and analyzed with respect to different stance subphases. Results: COP location significantly correlated with a shift of the elements medially or laterally. The linear model describing this correlation was found to be statistically significant. Conclusion: There was significant correlation between the plantar orientation of the shoe device configuration and the COP. Clinical Relevance: Changes in COP trajectory may be valuable in patients suffering from multiple foot disorders elevating pressure on the foot. Accurate COP control could aid in the manipulation of the forces acting on the proximal joints during gait. In addition, these findings may have implications in the field of biomechanical apparatus design and practice.
Fixation Strength of Anteriorly Inserted Headless Screws for Talar Neck Fractures
Authors: Capelle Jonathan H. , Couch Cory G. , Wells Kevin M. , Morris Randal P. , Buford William L. , Merriman David J. , Panchbhavi Vinod K. 
Published: March 2013

Background: For noncomminuted talar neck fractures, traditional fixation is with small fragment screws or cannulated screws. Newer screw systems on the market allow placement of cannulated headless screws, which provide compression by virtue of a variable-pitch thread. The headless construct has an inherent advantage, particularly for the talus, when the screws must be countersunk to prevent wear of the joint articular surfaces. This study tested the biomechanical fixation strength of cannulated headless variable-pitch screws compared with conventional cannulated screws, both placed in an anterior to posterior direction. Methods: A reproducible talar neck fracture was created in nine paired, preserved, cadaver talar necks using a materials testing machine. Talar head fixation was then performed with two cannulated headless variable-pitch 4/5 screws or two 4.0-mm conventional cannulated screws. The specimens were tested to failure and the fixations were normalized to their intact pairs and compared. Results: The headless variable-pitch screw fixation had significantly lower failure displacement than the conventional screw fixation. No significant differences were found between the two fixations for failure stiffness, load at failure or energy absorbed. Conclusions: Cannulated headless variable-pitch screws significantly improved failure displacement when compared to conventional cannulated screws in a cadaveric model, and may be a viable option for talus fracture fixation. Clinical Relevance: Headless, fully threaded, variable-pitch screws have inherent advantages over conventional screws in that they may be less damaging to the articular surface and can compress the fracture for improved reduction. This study demonstrates these screws are also biomechanically similar to conventional screws.
Comparative Analysis of Inter- and Intraligamentous Distribution of Sensory Nerve Endings in Ankle Ligaments
Authors: Rein Susanne , Hanisch Uwe , Zwipp Hans , Fieguth Armin , Lwowski Sophie , Hagert Elisabet 
Published: March 2013

Background: The aim of this study was to analyze the inter-, intraligamentous, and side-related patterns of sensory nerve endings in ankle ligaments. Methods: A total of 140 ligaments from 10 cadaver feet were harvested. Lateral: calcaneofibular, anterior-, posterior talofibular; sinus tarsi: lateral- (IERL), intermediate-, medial-roots inferior extensor retinaculum, talocalcaneal oblique and canalis tarsi (CTL); medial: tibionavicular (TNL), tibiocalcaneal (TCL), superficial tibiotalar, anterior/posterior tibiotalar portions; syndesmosis: anterior tibiofibular. Following immunohistochemical staining, the innervation and vascularity was analyzed between ligaments of each anatomical complex, left/right feet, and within the 5 levels of each ligament. Results: Significantly more free nerve endings were seen in all ligaments as compared to Ruffini, Pacini, Golgi-like, and unclassifiable corpuscles ( P ≤ .005). The IERL had significantly more free nerve endings and blood vessels than the CTL ( P ≤ .001). No significant differences were seen in the side-related distribution, except for Ruffini endings in right TCL ( P = .016) and unclassifiable corpuscles in left TNL ( P = .008). The intraligamentous analysis in general revealed no significant differences in mechanoreceptor distribution. Conclusions: The IERL at the entrance of the sinus tarsi contained more free nerve endings and blood vessels, as compared to the deeper situated CTL. Despite different biomechanical functions in the medial and lateral ligaments, the interligamentous distribution of sensory nerve endings was equal. Clinical Relevance: The intrinsic innervation patterns of the ankle ligaments provides an understanding of their innate healing capacities following injury as well as the proprioception properties in postoperative rehabilitation.
Etiology, endoscopic management and mortality of upper gastrointestinal bleeding in patients with cancer
Authors: Maluf‐Filho Fauze , Martins Bruno da Costa , de Lima Marcelo Simas , Leonardo Daniel Valdivia , Retes Felipe Alves , Kawaguti Fábio Shiguehissa , Sato Cezar Fabiano Manabu , Hondo Fábio Yuji , Safatle‐Ribeiro Adriana Vaz , Ribeiro Ulysses 
Published: March 2013

BackgroundThe source and outcomes of upper gastrointestinal bleeding (UGIB) in oncologic patients are poorly investigated.ObjectiveThe study aimed to investigate these issues in a tertiary academic referral center specialized in cancer treatment.MethodsThis was a retrospective study including all patients with cancer referred to endoscopy due to UGIB in 2010.ResultsUGIB was confirmed in 147 (of 324 patients) referred to endoscopy for a suspected episode of GI bleeding. Tumor was the most common cause of bleeding (N  = 35, 23.8%), followed by varices (N  = 30, 19.7%), peptic ulcer (N  = 29, 16.3%) and gastroduodenal erosions (N  = 16, 10.9%). Among the 32 patients with cancer of the upper GI tract, the main causes of bleeding were cancer (N  = 27, 84.4%) and peptic ulcer (N  = 5, 6.3%). Forty‐one patients (27.9%) presented with bleeding from the primary tumor or from a metastatic lesion, and seven received endoscopic therapy, with successful initial hemostasis in six (85.7%). Rebleeding and mortality rates were not different between endoscopically treated (N  = 7) and non‐treated (N  = 34) patients (28.6% vs. 14.7%, p  = 0.342; 43.9% vs. 44.1%, p  = 0.677). Median survival was 20 days, and the overall 30‐day mortality rate was 44.9%. There was no predictive factor of mortality or rebleeding.ConclusionTumor bleeding is the most common cause of UGIB in cancer patients. UGIB in cancer patients correlates with a high mortality rate regardless of the bleeding source. Current endoscopic treatments may not be effective in preventing rebleeding or improving survival.
MethylPCA: a toolkit to control for confounders in methylome-wide association studies
Authors: Chen Wenan , Gao Guimin , Nerella Srilaxmi , Hultman Christina M , Magnusson Patrik KE , Sullivan Patrick F , Aberg Karolina A , van den Oord Edwin JCG 
Published: March 2013

Abstract

Background
In methylome-wide association studies (MWAS) there are many possible differences between cases and controls (e.g. related to life style, diet, and medication use) that may affect the methylome and produce false positive findings. An effective approach to control for these confounders is to first capture the major sources of variation in the methylation data and then regress out these components in the association analyses. This approach is, however, computationally very challenging due to the extremely large number of methylation sites in the human genome.

Result
We introduce MethylPCA that is specifically designed to control for potential confounders in studies where the number of methylation sites is extremely large. MethylPCA offers a complete and flexible data analysis including 1) an adaptive method that performs data reduction prior to PCA by empirically combining methylation data of neighboring sites, 2) an efficient algorithm that performs a principal component analysis (PCA) on the ultra high-dimensional data matrix, and 3) association tests. To accomplish this MethylPCA allows for parallel execution of tasks, uses C++ for CPU and I/O intensive calculations, and stores intermediate results to avoid computing the same statistics multiple times or keeping results in memory. Through simulations and an analysis of a real whole methylome MBD-seq study of 1,500 subjects we show that MethylPCA effectively controls for potential confounders.

Conclusions
MethylPCA provides users a convenient tool to perform MWAS. The software effectively handles the challenge in memory and speed to perform tasks that would be impossible to accomplish using existing software when millions of sites are interrogated with the sample sizes required for MWAS.
Enzymatic analysis of the effect of naturally occurring Leu138Pro mutation identified in SHV β-lactamase on hydrolysis of penicillin and ampicillin
Authors: Rayamajhi Nabin , Joo Jeong Chan , Cha Seung Bin , Pokherl Subarna , Shin Min Kyung , Yoo Young Je , Yoo Han Sang 
Published: March 2013

Abstract

Background
The aim of this study was to analyze the significance of leucine to proline substitution at position 138(Leu138Pro) on the hydrolysis of penicillin and ampicillin that we identified in the bla
SHV gene of clinical Escherichia coli swine isolate.

Results
Kinetic analysis of the mutant proteins showed that K

m
value of the purified L138P mutant was comparatively higher than SHV-1, SHV-33 and SHV-33(L138P) enzyme for penicillin and ampicillin. Docking simulation of the SHV-1 and SHV-(L138P) enzymes also confirmed that β-lactamases preferred penicillin to ampicillin and the SHV-1 had a higher binding affinity for antibiotics compared to the SHV-(L138P) and other mutants.

Conclusions
Our result demonstrated that L138P has a reduced role in penicillin and ampicillin hydrolyzing properties of SHV β-lactamases. These naturally occurring mutations rendering reduced function of the existing protein could trigger the emergence or acquisition of more effective alternative mechanisms for β-lactam hydrolysis.
Comparative transcription analysis and toxin production of two fluoroquinolone-resistant mutants of Clostridium perfringens
Authors: Park Sunny , Park Miseon , Rafii Fatemeh 
Published: March 2013

Abstract

Background
Fluoroquinolone use has been listed as a risk factor for the emergence of virulent clinical strains of some bacteria. The aim of our study was to evaluate the effect of fluoroquinolone (gatifloxacin) resistance selection on differential gene expression, including the toxin genes involved in virulence, in two fluoroquinolone-resistant strains of Clostridium perfringens by comparison with their wild-type isogenic strains.

Results
DNA microarray analyses were used to compare the gene transcription of two wild types, NCTR and ATCC 13124, with their gatifloxacin-resistant mutants, NCTRR and 13124R. Transcription of a variety of genes involved in bacterial metabolism was either higher or lower in the mutants than in the wild types. Some genes, including genes for toxins and regulatory genes, were upregulated in NCTRR and downregulated in 13124R. Transcription analysis by quantitative real-time PCR (qRT-PCR) confirmed the altered expression of many of the genes that were affected differently in the fluoroquinolone-resistant mutants and wild types. The levels of gene expression and enzyme production for the toxins phospholipase C, perfringolysin O, collagenase and clostripain had decreased in 13124R and increased in NCTRR in comparison with the wild types. After centrifugation, the cytotoxicity of the supernatants of NCTRR and 13224R cultures for mouse peritoneal macrophages confirmed the increased cytotoxicity of NCTRR and the decreased cytotoxicity of 13124R in comparison with the respective wild types. Fluoroquinolone resistance selection also affected cell shape and colony morphology in both strains.

Conclusion
Our results indicate that gatifloxacin resistance selection was associated with altered gene expression in two C. perfringens strains and that the effect was strain-specific. This study clearly demonstrates that bacterial exposure to fluoroquinolones may affect virulence (toxin production) in addition to drug resistance.
A threshold method for immunological correlates of protection
Authors: Chen Xuan , Bailleux Fabrice , Desai Kamal , Qin Li , Dunning Andrew J 
Published: March 2013

Abstract

Background
Immunological correlates of protection are biological markers such as disease-specific antibodies which correlate with protection against disease and which are measurable with immunological assays. It is common in vaccine research and in setting immunization policy to rely on threshold values for the correlate where the accepted threshold differentiates between individuals who are considered to be protected against disease and those who are susceptible. Examples where thresholds are used include development of a new generation 13-valent pneumococcal conjugate vaccine which was required in clinical trials to meet accepted thresholds for the older 7-valent vaccine, and public health decision making on vaccination policy based on long-term maintenance of protective thresholds for Hepatitis A, rubella, measles, Japanese encephalitis and others. Despite widespread use of such thresholds in vaccine policy and research, few statistical approaches have been formally developed which specifically incorporate a threshold parameter in order to estimate the value of the protective threshold from data.

Methods
We propose a 3-parameter statistical model called the a:b model which incorporates parameters for a threshold and constant but different infection probabilities below and above the threshold estimated using profile likelihood or least squares methods. Evaluation of the estimated threshold can be performed by a significance test for the existence of a threshold using a modified likelihood ratio test which follows a chi-squared distribution with 3 degrees of freedom, and confidence intervals for the threshold can be obtained by bootstrapping. The model also permits assessment of relative risk of infection in patients achieving the threshold or not. Goodness-of-fit of the a:b model may be assessed using the Hosmer-Lemeshow approach. The model is applied to 15 datasets from published clinical trials on pertussis, respiratory syncytial virus and varicella.

Results
Highly significant thresholds with p-values less than 0.01 were found for 13 of the 15 datasets. Considerable variability was seen in the widths of confidence intervals. Relative risks indicated around 70% or better protection in 11 datasets and relevance of the estimated threshold to imply strong protection. Goodness-of-fit was generally acceptable.

Conclusions
The a:b model offers a formal statistical method of estimation of thresholds differentiating susceptible from protected individuals which has previously depended on putative statements based on visual inspection of data.
Intrarenal resistance index for the assessment of acute renal injury in a rat liver transplantation model
Authors: Kong Hai-Ying , Chen Fen , He Yong , Wu Lin-Jiao , Wang Li-Qing , Zhu Sheng-Mei , Zheng Shu-Sen 
Published: March 2013

Abstract

Background
Acute kidney injury (AKI) is a common complication after liver transplantation (LT) and associated with a high mortality. The renal resistive index (RI) is used to assess early renal function impairment in critical care patients. However, limited data are available concerning changes of renal RI and the development of AKI early after reperfusion. We approached to investigate the changes of renal RI and AKI after reperfusion in a rat liver transplantation model.

Methods
Rats were randomly divided into sham group or LT group. Ten rats in each group were used for the hemodynamic study and twenty for Doppler measurements during the procedure. Ten rats were sacrificed 30 min or 2 h after the reperfusion. We harvested kidneys, serum and urine for further analysis of the renal function.

Results
The intrarenal RI increased significantly in the anhepatic stage and decreased significantly after the reperfusion in the LT group compared with sham group (P < 0.05). AKI was seen after the reperfusion in the LT group. No correlation was noted between the RI and renal function parameters 30 min after reperfusion.

Conclusions
The intrarenal RI increased significantly during the anhepatic stage, and decreased significantly early after the reperfusion. Intrarenal RI was unable to assess renal function in a rat liver transplantation model.
Reduction of the domino effect in osteoporotic vertebral compression fractures through short-segment fixation with intravertebral expandable pillars compared to percutaneous kyphoplasty: a case control study
Authors: Hsieh Jui-Yang , Wu Chung-Ding , Wang Ting-Ming , Chen Hsuan-Yu , Farn Chui-Jia , Chen Po-Quang 
Published: March 2013

Abstract

Background
Osteoporotic vertebral compression fracture is the leading cause of disability and morbidity in elderly people. Treatment of this condition remains a challenge. Osteoporotic vertebral compression fractures can be managed with various approaches, but each has limitations. In this study, we compared the clinical outcomes obtained using short-segment fixation with intravertebral expandable pillars (I-VEP) to those obtained with percutaneous kyphoplasty in patients who had suffered vertebral compression fractures.

Methods
The study included 46 patients with single-level osteoporotic thoracolumbar fractures. Twenty-two patients in Group I underwent short-segment fixation with I-VEP and 24 patients in Group II underwent kyphoplasty. All patients were evaluated pre- and postoperatively using a visual analogue scale, anterior height of the fractured vertebra, and kyphotic angle of the fractured vertebra. The latter 2 radiological parameters were measured at the adjacent segments as well.

Results
There was no significant difference between the groups in terms of gender or fracture level, but the mean age was greater in Group II patients (p = 0.008). At the 1-year follow-up, there were no significant differences in the visual analogue scale scores, anterior height of the fractured vertebra, or the value representing anterior height above the fractured vertebra and kyphotic angle below the fractured vertebra, after adjusting for the patients’ gender, fracture level, and age. When considered separately, the anterior height below the fractured vertebra was significantly higher and the kyphotic angle above the fractured vertebra was significantly smaller in Group I than in Group II (p = 0.029 and p = 0.008, respectively). The kyphotic angle of the fractured vertebra was significantly smaller in Group II than in Group I (p < 0.001).

Conclusions
In older individuals with vertebral compression fractures, kyphoplasty restored and maintained the collapsed vertebral body with less kyphotic deformity than that induced by short-segment fixation with I-VEP. Short-segment fixation with I-VEP was more effective in maintaining the integrity of adjacent segments, which prevented the domino effect often observed in patients with osteoporotic kyphotic spines.
Stem cells: a new paradigm for disease modeling and developing therapies for age-related macular degeneration
Authors: Melville Heather , Carpiniello Matthew , Hollis Kia , Staffaroni Andrew , Golestaneh Nady 
Published: March 2013

Abstract
Age-related macular degeneration (AMD) is the leading cause of blindness in people over age 55 in the U.S. and the developed world. This condition leads to the progressive impairment of central visual acuity. There are significant limitations in the understanding of disease progression in AMD as well as a lack of effective methods of treatment. Lately, there has been considerable enthusiasm for application of stem cell biology for both disease modeling and therapeutic application. Human embryonic stem cells and induced pluripotent stem cells (iPSCs) have been used in cell culture assays and in vivo animal models. Recently a clinical trial was approved by FDA to investigate the safety and efficacy of the human embryonic stem cell-derived retinal pigment epithelium (RPE) transplantation in sub-retinal space of patients with dry AMD These studies suggest that stem cell research may provide both insight regarding disease development and progression, as well as direction for therapeutic innovation for the millions of patients afflicted with AMD.
Planning and adjustments for the control of reach extent in a virtual environment
Authors: Stewart Jill Campbell , Gordon James , Winstein Carolee J 
Published: March 2013

Abstract

Background
Skilled performance of reach actions includes both anticipatory planning and compensatory adjustments made while moving. The execution of reach actions in a virtual environment (VE) demonstrates similar characteristics to reaches performed in the real-world, however, it is unclear whether the VE itself significantly impacts movement planning or compensatory adjustments. The purpose of this study was to directly compare the use of planning and adjustments to control extent for unconstrained reach actions performed in an immersive VE to those performed in an analogous real-world environment (RWE).

Methods
Five non-disabled adults (29 ± 5 years) reached with the dominant, right arm to six targets presented in two directions (+45°, -45°) and three distances (8, 16, 24 cm) in a VE and an analogous RWE. Position data were sampled at 120 Hz from an electromagnetic marker on the index finger and differentiated to determine velocity and acceleration. The control of reach extent was compared between the two environments (paired t-test) as to the use of planning (correlation of peak acceleration with movement distance), compensatory adjustments prior to peak velocity (correlation of time to peak velocity with movement distance), and compensatory adjustments after peak velocity (variance in movement distance accounted for by deterministic statistical model).

Results
Reach movements were relatively fast (<400 msec) and scaled to target distance in both the VE and RWE. Overall, the control of reach extent was similar in all respects between the two environments. In both environments, a hybrid control pattern was observed. That is, individuals utilized a combined strategy that relied on both planning and compensatory adjustments to capture the target. Adjustments to the reach were evident prior to peak velocity through changes in acceleration duration as well as after peak velocity based on target information. The two factor deterministic statistical model (peak velocity, target distance) explained >92% of the variance in movement distance across participants and environments.

Conclusions
The VE did not impact movement planning or subsequent compensatory adjustments for the control of reach extent when directly compared to an analogous RWE. An immersive VE is a valid environment for the study of unconstrained reach actions.