bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-density, high surface area electromyography of the hamstring muscles during running and kicking
Authors: Sakthibalan S , Twycross-Lewis R , Woledge R , Hao Y , Morrissey D
Published: January 2011

Background

Surface electromyography (sEMG) is used extensively in the assessment of hamstring muscle activity. Conventional sEMG techniques may not fully represent overall muscle activity, despite clinically standardised placement of electrodes. High density EMG provides more information about biopotential activity but it is limited to signal collection over a small surface area. Our work proposes a low density high surface area EMG method to analyse muscle biopotentials over an entire muscle belly.

Objectives

To assess whether there is a pattern of EMG output over an entire muscle during running and repeated kicking.

Method

16 channel EMG and motion analysis data were collected for 10 healthy volunteers during treadmill running at 10 km/h, and kicking a football. Active infra-red motion analysis instrumentation was used to register limb segment movement with the raw time series EMG signals. Each EMG channel was subjected to Windowed Fourier Transform for construction of a false colour map for the hamstring. Each EMG and motion analysis channel were analysed by ANCOVA.

Results

Visual analysis showed that different areas of the hamstring muscles are active at different points in the running cycle independently of each other. Quantitative analysis within a single subject showed main effects for electrode position and stride point (p<0.001) during running. A significant interaction between stride point and electrode position was noted.

Conclusion

Results suggest the presence of an EMG activity pattern showing consistent variation within stride-point and channel location during running. A larger subject group is needed to further investigate EMG patterns in kicking. The scope for further research using the results of this paper as a foundation is vast, with the future inclusion of wireless EMG, electrode arrays and custom garments. The findings may lead to an application in a screening, rehabilitation and diagnosis setting.
Changes in the symptoms and ultrasound signs of achilles tendinopathy during a twelve week course of loaded eccentric training: a pilot study
Authors: Jangra A , Perry M , Maffulli N , Malliaras P , Morrissey D
Published: January 2011

Background

12 weeks of eccentric exercise has been shown to be a useful therapy for Achilles tendinopathy, but little is known of the time-course of recovery, or the nature of any structural changes during therapy.

Objectives

To assess the time-course and pattern of Achilles tendon symptoms, thickness, stiffness, and ultrasound (US) signs during 12 weeks of eccentric exercise (EE).

Methods

Five subjects of age range (mean) 38–52 (46) years with main-body AT were included. For each subject, serial measurements of VISA-A score, the presence of neovascularisation and grey-scale US signs within the tendon, and the thickness of the Achilles tendon at 3 points were recorded for the first three weeks of a twelve week EE programme.

Results

Median VISA-A score increased from 48.5 to 54.5 (p=0.116). Median mid-tendon thickness decreased from 0.834 cm to 0.790 cm (p=0.107). A trend towards a decrease in tendon thickness was noted directly superior to the retrocalcaneal bursa and at the soleus myotendinous junction. Neovascularisation, paratenon blurring and hypoechoic areas improved in 1/3, 1/3 and 2/5 tendons respectively. No significant change occurred in median tendon stiffness.

Conclusion

3 weeks of EE do not produce significant changes in AT symptoms and tendon thickness or stiffness, but improve US signs and neovascularisation in some subjects. The non-significance of findings may be a type II error and further work with larger sample sizes is planned.
Platelet-rich plasma for chronic achilles tendinopathy: a double-blind randomised controlled trial with one year follow-up
Authors: de Jonge S , de Vos R J , Weir A , van Schie H T M , Bierma-Zeinstra S M A , Verhaar J A N , Weinans H , Tol J L
Published: January 2011

Introduction

Chronic Achilles tendinopathy occurs frequently and is very hard to treat. The disease involves local degeneration of tendon tissue, of which regeneration may be improved by injecting platelet-rich plasma (PRP), an increasingly used therapy for releasing growth factors into degenerative tendon. However, high-quality randomised clinical trials on this topic are lacking. The aim of this study was to evaluate the effect of a PRP injection in patients with chronic Achilles tendinopathy.

Methods

In this stratified, block randomised, double-blind, placebo-controlled trial at single center 54 patients aged 18–70 years were randomised in two treatment groups. Next to an eccentric training program the patients received a blinded injection containing either PRP group or saline (placebo group). Primary outcome, the objective and validated Victorian Institute of Sports Assessment-Achilles (VISA-A) score, was assessed and ultrasound examination was performed at baseline and all follow-up appointments.

Results

After randomisation into the PRP group (n=27) and the placebo group (n=27) there was a complete follow-up. After one year, the mean VISA-A score improved in both the PRP-group and the placebo group. There was no significant difference in increase between both groups (adjusted between-group difference, 5.5; 95% CI, −4.9 to 15.8, p=0.292). Ultrasonographic tendon structure improved significantly in both groups, but not significant different between both groups (adjusted between-group difference, 1.2 %, 95% CI, −4.1 to 6.6, p=0.647)

Conclusion

One-year follow-up analysis of the world’s first randomised controlled trial showed no evidence for the use of platelet-rich plasma injection in chronic Achilles tendinopathy. These findings are in line with our 6 months results (De Voset alJAMA 2010).
Nutrition intakes and practices of marathon swimmers
Authors: Papadopoulou S K , Xyla E , Grammatikopoulou M , Hassapidou M
Published: January 2011

Introduction

The purpose of this study was to assess nutritional status of swimmers, during the marathon swimming event of crossing Toroneos (26 km). The participants were 24 athletes mean aged 36.08±12.52 years. The sample was divided into two groups, according to their age: (1) 18–34 years (12 athletes) and (2) 35–68 years (12 athletes).

Methods

The athletes recorded their food intake for 3 training days and during the race. Food intake was analysed in nutrients using the Food Processor nutrition program (version 7.4, 1997, ESHA Research Salem, Oregon). For the statistical analysis, SPSS (v.15) was used.

Results

The athletes had inadequate intake of energy during the training period. There were no differences in energy intake, according to age (2144±190 kcal for the athletes aged 18–24 years and 2181±198 kcal for the athletes aged 35–68 years). Both groups had inadequate intake of carbohydrates (4.6±0.96 g/kg body weight or 67.55±10.74% of energy intake, for the younger athletes and 4.0±1.21 g/kg BW or 68.44±9.16% of EI for the older athletes). Protein intake was 0.95±0.20 g/kg BW or 14.30±4.46% of EI, and 0.93±0.31 g/kg BW or 15.71±3.81% of EI for the younger and the older athletes, respectively. Fat intake was above the recommended values for both age groups (18–34 years: 32.70±2.60% of EI, 35–68 years: 35.13±3.10% of EI). Both groups met the recommended daily allowances (RDA) for all micronutrients, with the exception of B3, Zn and Mn.

During the race, the athletes consumed 12 types of solid food and 7 types of fluids. The preferred foods were: bananas, energy gel and honey. From liquid beverages the preferred ones were: isotonic drinks, water and soft type cola. Energy intake during the race was 1048±447 kcal for the younger group and 948±504 kcal for the older group. There was no difference between the two groups in energy intake. Younger athletes maintain a stable body weight, while older ones lost 1.62±1.89 kg, during the race.

Conclusion

The athletes had insufficient energy and carbohydrate intake, factors that can influence their athletic performance. There was no significant difference between the two groups in energy and macronutrient intake. However, the older athletes had higher demands during the race in energy and nutrients, due to their higher energy expenditure, as the duration of the race was longer for them and lead to a loss of body weight.
Validation of a non-radiographic ankle arthrometer
Authors: Nauck Tanja , Lohrer Heinz
Published: January 2011

Introduction

Commonly used stress tests require radiography. The respective reliability and sensitivity is still under debate. We developed a non-radiographic ankle arthrometer to objectively assess mechanical ankle stability. The aim of the present study was to validate the ankle arthrometer in a cadaver and in vivo set up.

Methods

Cadaver studyNine cadaver specimens were tested under different anterior drawer load and ankle angle positions against standardised radiography. Lateral ankle ligaments were sequentially cut during testing procedure. Stiffness was calculated and the diagnostic validity of the ankle arthrometer was analysed.

In vivo study23 subjects participated in the study. An orthopaedic surgeon first performed a manual anterior talar drawer test to classify the subjects’ ankles as stable or unstable. Subjects then underwent ankle arthrometer testing up to 200 N anterior drawer load twice and the stiffness were calculated.

Results

Cadaver studyStable and unstable ankles were significantly differentiated by stiffness analyses (p=0.01) with the ankle arthrometer adjusted to 0 degrees of plantarflexion and 50 N anterior drawer load application.

Results from the ankle arthrometer radiographs and the standardised stress testing device correlated significantly (r=0.73–0.94; p=0.00–0.03). Stiffness analyses discriminate stable and unstable ankles with a sensitivity of 91.7% and specificity of 62.5%.

In vivo studyUsing the manual anterior drawer test, 16 ankles were classified as stable and 7 as unstable. Stiffness group analysis differentiated stable from unstable ankles significantly (p=0.00 and p=0.01). Test-retest demonstrated an accurate reliability (intraclass correlation coefficient=0.80).

Conclusions

Validation and reliability of the non-radiographic ankle arthrometer was demonstrated in a cadaver and in vivo set up. The ankle arthrometer stiffness analyses may be relevant to screen athletes at risk for lateral ankle instability, for follow-up studies, and to implement preventive strategies.
Effect of trampoline-based intervention program in static balance of children with developmental coordination disorder
Authors: Mitsiou M , Sidiropoulou M , Giagkazoglou P , Tsimaras V ,   Laboratory of Developmental Medicine and Special Education
Published: January 2011

Published studies have shown that the presence of developmental coordination disorder (DCD) (APA,1994), involves about 5–15% of the population. This work focused on the study of the effect of an intervention program with trampoline on school children of ages from 6 to 11 years old, exhibiting DCD. The study included DCD detection with the quantitative diagnosis test of neuromuscular coordination of the entire body (Körperkoordinationstest für Kinder KTK, Kiphard & Schilling, 2002, 1974), leading to 20 (out of a total of 200) children exhibiting DCD (intervention and control groups). Furthermore, a group of 10 students constituted a control group without DCD. A static balance measurement test was applied, using the balance platform (footchecker 3.2, Lovan Engineering S.r.l., Bologna, Italy) for all 30 students as follows: standing with open and closed eyes, and balance maintenance while standing on each one foot for 30″. An intervention program for multifaceted practicing of coordination abilities with trampoline was also applied to the intervention group, whereas the control groups followed the typical physical education timetable. An important effect of the intervention group (p<0.001), regarding the SD of the centre of pressure (CP) in the anteroposterior axis (Y), was observed during measurement with open eyes and standing on the right foot, as well as in the collateral axis (X), while standing on the left foot. A statistically significant difference (p<0.001) was also exhibited in the Y-axis, concerning the shifting of the CP, for the case of measurement with open eyes and standing on each foot. Regarding the within groups interaction, a significant effect (p<0.05) was observed for the shifting of the CP along the Y-axis for all conditions of measurement. These results support the hypothesis that the use of trampoline may improve the neuromuscular coordination, hence could provide a valid diagnostic tool for DCD.
Clinical practice guide for muscular injuries: epidemiology, diagnosis, treatment and prevention
Authors: Valle X
Published: January 2011

Lecture 20

Muscular injuries are very frequent in sport. The epidemiological studies show that muscular injuries represent more than 30% of all injuries (1.8–2.2/1000 h of exposure), which means that a professional football team suffers an average of 12 muscular injuries per season, equivalent to more than 300 lost sporting days.

Despite their high frequency and the interest in finding solutions, there is little scientific evidence on aspects as important as prevention and treatment, we will outline some weak points. Diagnosis of muscular injuries is based on clinical medicine, fundamentally on symptomatology and especially on the anamnesis of the injury mechanism and physical examination. Imaging studies through the musculoskeletal echography and magnetic resonance are complementary studies, despite the fact that they could be increasingly more useful when confirming a diagnosis or especially when giving a prognosis. There is no sufficiently specific biochemical marker available that could help with the diagnosis of the seriousness and the definitive prognosis of each of the different muscular injuries.

Treatment guidelines for muscular injuries do not follow a unique model, despite the fact that the different alternatives have been modified very little. Finally, new expectations have been raised thanks to research within the field of biological repair and regeneration.

Prevention programmes can reduce the incidence of suffering muscular injuries, but scientific evidence is still limited and it has only been possible to verify them in certain groups of sportsmen.

The objective of this talk is to show the diagnostic, therapeutic and preventive approaches that should be taken when faced with the various muscular injuries suffered by the football players of Barcelona football club. The protocols are based on current knowledge from recent years in the daily work of dealing with these types of injuries.
Platelet-rich plasma usage in orthopaedics and sports medicine
Authors: Eglinton Daniel Thomas
Published: January 2011

Lecture 22

It's been almost 50 years since the discovery of BMPs in the 1960s. Despite the advances in technology we still remain in the infancy period concerning the development of the vast potential available from growth factors. A plethora of articles on platelet-derived growth factors have recently begun appearing in all areas of medicine. The results, techniques and experiences of the examiners have been varied. There have been very few physicians that have believed and used this technology since its inception 17 years ago, and still remain committed to its uses today.

This lecture will provide a review of the biology of BMPs and a literature review, 17 years of experience with its use in orthopaedics disorders, as well as a treatment protocol. Details on injection technique utilising C-arm and ultrasound guidance will also be discussed.

Current treatment regimens are costly, and variable in their results. It is the hope of many that these technologies will allow us to be proactive instead of reactive, therefore, taking the costly care out of the healthcare industry. For those of us that have tried this primordial soup, we feel its time to lead, follow, or get out of the way, as this technology is here to stay.
University of Craiova, Faculty of Physical education, Sports & Kinesiology
Authors: Ligia Rusu
Published: January 2011

Lecture 26

University of Craiova is one of the most important universities in Romania. It includes also Faculty of Physical Education, Sport and Kinesiology that prepare the future specialists in sport performance, trainers and sport rehabilitation. Most of the teachers of this faculty are sports medicine physicians and they have also medical activity in the Sport Medicine Department of Emergency Hospital Craiova.

In our university we coordinate the programmes that included important aspects of sports medicine like: anatomy and biomechanic, physiology and sport physiology, rehabilitation and recovery in sport, sports medicine in chronic diseases. Practical activity included working with sports centres from south region of Romania, by specific assistance to athletes in Sports Medicine Department of our hospital. The sports medicine physicians in accordance with European Standards of Sports Medicine speciality give specific assistance by: clinical examination, cardiology exam, orthopaedic and rehabilitation exams, assessment of effort capacity and functional assessment, biometric assessment. The final diagnosis helps the athletes to have the best recommendations regards effort, nutrition, recovery and rehabilitation.

In side of our university we have a research centre named ‘Research centre for study human body motricity’. This research centre has an activity in according with European ethics recommendations. It has departments for research in field of sports medicine and sport performance, sport rehabilitation using results of fundamental research regards how the sport activity induce functional and structural changes of human body. The centre has the following departments: motric anthropology, structural anthropology, kinesiology, physical therapy, sport medicine, statistic analyse of research. Focus group of our research are physicians from sports medicine, orthopaedics, rehabilitation and also athletes and trainers.

Research activity in field of sports medicine is developed in relation with practical activity in field of sports by cooperation with sports centres like: athletic team, football teams, volleyball, handball and basket teams.

In Romania sports medicine is a medical speciality and the future specialist have to prepare in this field for 4 years and they obtain the title of sports medicine physician specialist. During 4 years they obtain knowledge regards traumatology, physical therapy, cardiologic assessment of heart athletes, sport specific adaptations and specific rehabilitation and training.
Gene, injury and performance
Authors: Maffulli Nicola
Published: January 2011

Lecture 28

The limit of each individual to perform a given type of exercise depends on the nature of the task, and is influenced by a variety of factors, including psychology, environment and genetic make up. Genetics provide useful insights, as sport performances can be ultimately defined as a polygenic trait. The physical performance phenotypes for which a genetic basis can be suspected include endurance capacity, muscle performance, physiological attitude to train and ability of tendons and ligaments to withstand injury. The translation of an advantageous genotype into a champion's phenotype is still influenced by environmental, psychological and sociological factors. Since exercise training regulates the expression of genes encoding various enzymes in muscle and other tissues, genetic research in sports will help clarify several aspects of human biology and physiology, such as RNA and protein level regulation under specific circumstances. Genetic testing in sport would permit to identify individuals with optimal physiology and morphology, and also those with a greater capacity to respond/adapt to training and a lesser chance of suffering from injuries. Ethical and practical caveats should be clearly emphasised. The current scientific evidence on the relationship between genetics and sports look promising. There is a need for additional studies to determine whether genomewide genotyping arrays would be really useful and cost-effective.
Sudden cardiac death in the young
Authors: Sharma Sanjay
Published: January 2011

Lecture 30

The sudden death of a young (<35 years old) is a particularly tragic event given the potential number of life years lost. There are between 10 and 12 sudden cardiac deaths in young individuals per week in the UK. Most deaths are secondary to inherited or congenital abnormalities of the heart, the commonest being the hereditary cardiomyopathies. The phenotypic manifestation of some of the disorders implicated is heterogeneous and therefore expert input is essential. Most disorders can be diagnosed using non-invasive investigations and treatments range from life style modifications to cardiac surgery.

Objectives

To define:

magnitude of the problem

demographics of the victims

causes of sudden cardiac death

clinical manifestations of disorders

investigation and management of conditions causing sudden cardiac death.
Posterior cruciate ligament injuries in sports: treatment options
Authors: Tsikouris George
Published: January 2011

Lecture 4

Diagnosis and management of posterior and cruciate ligament tears has advanced over the past two decades due to important understanding of the natural history of injury and basic science principles. Despite the current advances, our understanding of posterior cruciate ligament (PCL) injury and treatment continues to lag behind that of the anterior cruciate ligament (ACL). In addition, there is still controversy regarding indications for surgical intervention, use of one versus two reconstructive graft bundles, location of the femoral tunnels and the ideal degree of graft tensioning.

The classic mechanism of injury to the PCL in sports due to a fall on a flexed knee with the foot in plantar flexion. A PCL injury can be partial or complete and it can be isolated or involve multiple ligaments.

The grading system is normal: A, B and C. Grade A is defined as partial tear and grade B as a complete PCL tear. Grade C PCL injuries are frequently associated with additional injury to the posterolateral corner or the medial aspect of the knee.

In general, acute isolated grade A and B PCL injuries can be treated non-operatively. In grade C injuries with associated ligament pathology, we recommend repairing or reconstructing all ligaments.
Overview of exercise induced lower leg pain
Authors: Allen Mike
Published: January 2011

Lecture 8

This paper discusses the common causes of exercise induced lower leg pain, including chronic compartment syndrome (CCS), medial tibial stress syndrome (MTSS) and chronic calf tears (CCT).

The pathogenesis, clinical presentation, diagnosis and treatment of the more popular conditions are discussed.

CCSs are due to an increased pressure in one or more of the four compartments of the lower leg, brought on by exercise and relieved by rest. Clinical examination of the limb is normal. Diagnosis is made by measuring the compartment pressures during exercise. Treatment is by a subcutaneous fasciotomy of the affected compartments.

MTSS is thought to be due to abnormal biomechanics leading to a periostalgia of the inner tibial border both during and after exercise, with symptoms lasting up to 24–48 h postexercise. Patients always locate their pain to the inner tibial border. Examination of the limb shows the lower and often the middle inner tibial border to be tender. Diagnosis is largely clinical but may be helped by MRI scans. Treatment is initially by physiotherapy in the form of flexibility and strengthening exercises and the fitting of orthotics. If this fails then major surgery is the only other alternative.

CCT occur as a result of scar tissue in the muscle or adhesions developing between the fascia and the muscle causing pain in the posterior aspect of the calf. Often there is a past history of an acute calf tear. The pain presents during a run and often the athlete will describe pain in the posterior aspect of the calf which will increase with the intensity of exercise and if they try to run through the pain they experience a tearing sensation in the calf muscle sufficient to stop them exercising and cause them to limp up to a period of 3 days. Clinical examination often reveals tenderness over the medial head of gastrocnemius. An MRI scan may or may not aide in the diagnosis. Treatment initially is in the form of physiotherapy and if this fails then operative surgery which carries an 80% success rate.

Finally other rarer causes of exercise induced leg pain are discussed, namely muscle hernia, popliteal artery entrapment syndrome, nerve entrapments and metabolic disorders.
A NOVEL SWITCHED-CURRENT SUCCESSIVE APPROXIMATION ADC
Authors: TANG XIAN , PUN KONG PANG
Published: January 2011

A novel switched-current successive approximation ADC is presented in this paper with high speed and low power consumption. The proposed ADC contains a new high-accuracy and power-efficient switched-current S/H circuit and a speed-improved current comparator. Designed and simulated in a 0.18-μm CMOS process, this 8-bit ADC achieves 46.23 dB SNDR at 1.23 MS/s consuming 73.19 μW under 1.2 V voltage supply, resulting in an ENOB of 7.38-bit and an FOM of 0.357 pJ/Conv.-step.
THE WOLFRAM MACHINE
Authors: FORTUNA LUIGI , FRASCA MATTIA , FIORE ANGELO SARRA , CHUA LEON O.
Published: January 2011

A new stand-alone complex system hardware emulator, called the Wolfram Machine, is introduced in this paper. The system is a programmable hardware cellular automaton able to emulate and show the outcome of all elementary cellular automata, allowing for their experimental analysis. The system consists of an LED matrix and a board equipped with a microcontroller. This simple low-cost system can be programmed to reproduce the complex behavior of Wolfram's cellular automata, ranging from periodic patterns to Turing machines and Isles of Eden. A complete gallery of experiments is included.
CRITERION OF CHAOS FOR SWITCHED LINEAR SYSTEMS WITH CONTROLLERS
Authors: XIE LINGLI , ZHOU YI , ZHAO YI
Published: January 2011

In this paper, a sufficient criterion for time-invariant switched linear systems with controllers to be chaotic in the sense of Li–Yorke and Devaney is presented. The switched linear systems consist of an unstable subsystem with expanding flows and a controllable subsystem. It is exposed that the controllability of dynamic systems, instead of asymptotic stability, plays an important role in generating chaos. Finally, we give a numerical simulation for an example with some variable parameters to illustrate the validity of the result.
LIMIT CYCLES AND CENTERS IN A CUBIC PLANAR SYSTEM
Authors: CHERKAS LEONID , ROMANOVSKI VALERY G. , XING YEPENG
Published: January 2011

In this paper, we obtain the necessary and sufficient conditions for centers for a cubic planar system with Z2-symmetry studied by Yu and Han [2004]. We also give an example of such a system with 12 limit cycles of "real" (relatively large) size.
FIRM EVIDENCE OF CHAOS FOR HEARTBEATS IN DOGS UNDER CONSTANT FLOW VENTILATION
Authors: NAKAI TERUMI , HIRATA YOSHITO , HORAI SHUNSUKE , AKAGI MICHIO , AIHARA KAZUYUKI
Published: January 2011

We show that heartbeats can be chaotic under the influence of the central nerve systems only. By using constant flow ventilation, the heartbeats of dogs were separated from phasic respiratory motion and measured. By using techniques of nonlinear time series analysis, three pieces of evidence are presented for the existence of chaos.
ACOUSTIC RAY STABILITY FOR LONG-RANGE SOUND SPEED PROFILE TRANSITION SCENARIOS
Authors: BÓDAI TAMÁS , WIERCIGROCH MARIAN
Published: January 2011

Range-dependency in the background sound speed structure for deep ocean propagation scenarios is typical. Here a special case is considered when there is a gradual transition between single and double minimum sound speed profiles. Ray stability, an important measure for many applications, is analyzed. It is done by studying the unperturbed autonomous ray equations in the quasistatic limit. The wave guide is mapped out in terms of constant action curves in the vertical plane of propagation, which reveals a bifurcation effect in the studied wave guides. Conditions for the constancy or a sudden change of the action of a ray trajectory, an effect that impacts on the "use" of a ray, are given.
CONTROLLER DESIGN AND ANALYSIS FOR A TWO-CELL DC-DC CONVERTER IN THE PRESENCE OF SATURATION
Authors: HAMZA R. , FEKI M. , DERBEL N. , ROBERT B. G. M. , EL AROUDI A.
Published: January 2011

In this work, a zero static error proportional controller for a two-cell DC-DC buck converter is synthesized and analyzed. Under a traditional proportional control scheme, the system presents a constant error of the current supplying the output load. As the proportional feedback gain is increased, the average static error decreases. However, subharmonic oscillations and chaotic behavior emerge beyond successive bifurcations. To achieve zero current and zero voltage static error, we suggest a modification of the traditional proportional controller. By optimizing the feedback gain, the settling time is also decreased. Then, using nonlinear analysis and Lyapunov stability theory, we prove that zero static error is achieved even in the presence of duty cycle saturation. Numerical simulations are presented to confirm our theoretical results.
TEST TIME REDUCTION THROUGH OPTIMAL DEGRADATION TESTING
Authors: YANG GUANGBIN
Published: January 2011

In industry, bogey testing, also known as the zero-failure testing, is often used to demonstrate that a product achieves the required reliability at a high confidence level. This test method is simple to apply; however, it requires excessive test time and/or a large sample size, and thus is usually unaffordable. For some products whose failure is defined as a performance characteristic exceeding a threshold, it is possible to measure the performance characteristic during testing. The measurement data can be employed to predict whether or not a test unit will fail by the end of test. When there are sufficient data to make such a prediction with a high degree of confidence, the test of the unit can be terminated. As a result, the test time is reduced. Yang studies the test time reduction for Weibull and binomial distributions.1 This paper describes the test method for lognormal distribution. In particular, this paper describes the sample size, degradation models, and cost function for the lognormal distribution. Then the paper describes the optimum test plans, which choose the optimal sample size and the expected test time, by minimizing the total test cost and simultaneously satisfying the constraints on the type II error and the available sample size. An example is given to illustrate the test method.
Wnt4 activates the canonical β-catenin pathway and regulates negatively myostatin: functional implication in myogenesis
Authors: Bernardi Henri , Gay Stephanie , Fedon Yann , Vernus Barbara , Bonnieu Anne , Bacou Francis
Published: January 2011

Expression of Wnt proteins is known to be important for developmental processes such as embryonic pattern formation and determination of cell fate. Previous studies have shown that Wn4 was involved in the myogenic fate of somites, in the myogenic proliferation, and differentiation of skeletal muscle. However, the function of this factor in adult muscle homeostasis remains not well understood. Here, we focus on the roles of Wnt4 during C2C12 myoblasts and satellite cells differentiation. We analyzed its myogenic activity, its mechanism of action, and its interaction with the anti-myogenic factor myostatin during differentiation. Established expression profiles indicate clearly that both types of cells express a few Wnts, and among these, only Wnt4 was not or barely detected during proliferation and was strongly induced during differentiation. As attested by myogenic factors expression pattern analysis and fusion index determination, overexpression of Wnt4 protein caused a strong increase in satellite cells and C2C12 myoblast differentiation leading to hypertrophic myotubes. By contrast, exposure of satellite and C2C12 cells to small interfering RNA against Wnt4 strongly diminished this process, confirming the myogenic activity of Wnt4. Moreover, we reported that Wnt4, which is usually described as a noncanonical Wnt, activates the canonical β-catenin pathway during myogenic differentiation in both cell types and that this factor regulates negatively the expression of myostatin and the regulating pathways associated with myostatin. Interestingly, we found that recombinant myostatin was sufficient to antagonize the differentiation-promoting activities of Wnt4. Reciprocally, we also found that the genetic deletion of myostatin renders the satellite cells refractory to the hypertrophic effect of Wnt4. These results suggest that the Wnt4-induced decrease of myostatin plays a functional role during hypertrophy. We propose that Wnt4 protein may be a key factor that regulates the extent of differentiation in satellite and C2C12 cells.
Temporal and spatial patterns of endogenous danger signal expression after wound healing and in response to lymphedema
Authors: Zampell Jamie C. , Yan Alan , Avraham Tomer , Andrade Victor , Malliaris Stephanie , Aschen Seth , Rockson Stanley G. , Mehrara Babak J.
Published: January 2011

While acute tissue injury potently induces endogenous danger signal expression, the role of these molecules in chronic wound healing and lymphedema is undefined. The purpose of this study was to determine the spatial and temporal expression patterns of the endogenous danger signals high-mobility group box 1 (HMGB1) and heat shock protein (HSP)70 during wound healing and chronic lymphatic fluid stasis. In a surgical mouse tail model of tissue injury and lymphedema, HMGB1 and HSP70 expression occurred along a spatial gradient relative to the site of injury, with peak expression at the wound and greater than twofold reduced expression within 5 mm ( P < 0.05). Expression primarily occurred in cells native to injured tissue. In particular, HMGB1 was highly expressed by lymphatic endothelial cells (>40% positivity; twofold increase in chronic inflammation, P < 0.001). We found similar findings using a peritoneal inflammation model. Interestingly, upregulation of HMGB1 (2.2-fold), HSP70 (1.4-fold), and nuclear factor (NF)-κβ activation persisted at least 6 wk postoperatively only in lymphedematous tissues. Similarly, we found upregulation of endogenous danger signals in soft tissue of the arm after axillary lymphadenectomy in a mouse model and in matched biopsy samples obtained from patients with secondary lymphedema comparing normal to lymphedematous arms (2.4-fold increased HMGB1, 1.9-fold increased HSP70; P < 0.01). Finally, HMGB1 blockade significantly reduced inflammatory lymphangiogenesis within inflamed draining lymph nodes (35% reduction, P < 0.01). In conclusion, HMGB1 and HSP70 are expressed along spatial gradients and upregulated in chronic lymphatic fluid stasis. Furthermore, acute expression of endogenous danger signals may play a role in inflammatory lymphangiogenesis.
Maternal diabetes increases large conductance Ca2+-activated K+outward currents that alter action potential properties but do not contribute to attenuated excitability of parasympathetic cardiac motoneurons in the nucleus ambiguus of neonatal mice
Authors: Lin Min , Hatcher Jeff T. , Chen Qing-Hui , Wurster Robert D. , Li Lihua , Cheng Zixi (Jack)
Published: January 2011

Previously, we demonstrated that maternal diabetes reduced the excitability and increased small-conductance Ca2+-activated K+(SK) currents of parasympathetic cardiac motoneurons (PCMNs) in the nucleus ambiguus (NA). In addition, blockade of SK channels with apamin completely abolished this reduction. In the present study, we examined whether maternal diabetes affects large-conductance Ca2+-activated K+(BK) channels and whether BK channels contribute to the attenuation of PCMN excitability observed in neonates of diabetic mothers. Neonatal mice from OVE26 diabetic mothers (NMDM) and normal FVB mothers (control) were used. The pericardial sac of neonatal mice at postnatal days 7–9 was injected with the tracer X-rhodamine-5 (and 6)-isothiocyanate 2 days prior to the experiment to retrogradely label PCMNs in the NA. Whole cell current- and voltage-clamps were used to measure spike frequency, action potential (AP) repolarization (half-width), afterhyperpolarization potential (AHP), transient outward currents, and afterhyperpolarization currents ( IAHP). In whole cell voltage clamp mode, we confirmed that maternal diabetes increased transient outward currents and IAHPcompared with normal cells. Using BK channel blockers charybdotoxin (CTx) and paxilline, we found that maternal diabetes increased CTx- and paxilline-sensitive transient outward currents but did not change CTx- and paxilline-sensitive IAHP. In whole cell current-clamp mode, we confirmed that maternal diabetes increased AP half-width and AHP, and reduced excitability of PCMNs. Furthermore, we found that after blockade of BK channels with CTx or paxilline, maternal diabetes induced a greater increase of AP half-width but similarly decreased fast AHP without affecting medium AHP. Finally, blockade of BK channels decreased spike frequency in response to current injection in both control and NMDM without reducing the difference of spike frequency between the two groups. Therefore, we conclude that although BK transient outward currents, which may alter AP repolarization, are increased in NMDM, BK channels do not directly contribute to maternal diabetes-induced attenuation of PCMN excitability. In contrast, based on evidence from our previous and present studies, reduction of PCMN excitability in neonates of diabetic mothers is largely dependent on altered SK current associated with maternal diabetes.
House sparrows (Passer domesticus) increase protein catabolism in response to water restriction
Authors: Gerson Alexander R. , Guglielmo Christopher G.
Published: January 2011

Birds primarily rely on fat for energy during fasting and to fuel energetically demanding activities. Proteins are catabolized supplemental to fat, the function of which in birds remains poorly understood. It has been proposed that birds may increase the catabolism of body protein under dehydrating conditions as a means to maintain water balance, because catabolism of wet protein yields more total metabolic and bound water (0.155·H2O−1·kJ−1) than wet lipids (0.029 g·H2O−1·kJ−1). On the other hand, protein sparing should be important to maintain function of muscles and organs. We used quantitative magnetic resonance body composition analysis and hygrometry to investigate the effect of water restriction on fat and lean mass catabolism during short-term fasting at rest and in response to a metabolic challenge (4-h shivering) in house sparrows ( Passer domesticus ). Water loss at rest and during shivering was compared with water gains from the catabolism of tissue. At rest, water-restricted birds had significantly greater lean mass loss, higher plasma uric acid concentration, and plasma osmolality than control birds. Endogenous water gains from lean mass catabolism offset losses over the resting period. Water restriction had no effect on lean mass catabolism during shivering, as water gains from fat oxidation appeared sufficient to maintain water balance. These data provide direct evidence supporting the hypothesis that water stress can increase protein catabolism at rest, possibly as a metabolic strategy to offset high rates of evaporative water loss.
Neocortical layer 4 as a pluripotent function linearizer
Authors: Favorov Oleg V. , Kursun Olcay
Published: January 2011

A highly effective kernel-based strategy used in machine learning is to transform the input space into a new “feature” space where nonlinear problems become linear and more readily solvable with efficient linear techniques. We propose that a similar “problem-linearization” strategy is used by the neocortical input layer 4 to reduce the difficulty of learning nonlinear relations between the afferent inputs to a cortical column and its to-be-learned upper layer outputs. The key to this strategy is the presence of broadly tuned feed-forward inhibition in layer 4: it turns local layer 4 domains into functional analogs of radial basis function networks, which are known for their universal function approximation capabilities. With the use of a computational model of layer 4 with feed-forward inhibition and Hebbian afferent connections, self-organized on natural images to closely match structural and functional properties of layer 4 of the cat primary visual cortex, we show that such layer-4-like networks have a strong intrinsic tendency to perform input transforms that automatically linearize a broad repertoire of potential nonlinear functions over the afferent inputs. This capacity for pluripotent function linearization, which is highly robust to variations in network parameters, suggests that layer 4 might contribute importantly to sensory information processing as a pluripotent function linearizer, performing such a transform of afferent inputs to a cortical column that makes it possible for neurons in the upper layers of the column to learn and perform their complex functions using primarily linear operations.
Adaptations in biceps brachii motor unit activity after repeated bouts of eccentric exercise in elbow flexor muscles
Authors: Dartnall Tamara J. , Nordstrom Michael A. , Semmler John G.
Published: January 2011

The purpose of this study was to examine changes in motor unit activity in the biceps brachii muscle after an initial ( Bout 1) and repeated ( Bout 2) session of eccentric exercise separated by 1 wk. Eight subjects (aged 22 ± 2 yr) participated in experimental assessments of neuromuscular function obtained before, immediately after, 24 h after, and 7 days after each exercise bout. Each experimental session involved assessments of elbow-flexor force and biceps and triceps brachii electromyography during maximum voluntary isometric contractions (MVCs) and constant-force isometric contractions at five contraction intensities (5–50% MVC), along with indicators of muscle damage (muscle pain and passive tension). In addition, motor unit recordings were obtained before exercise, 7 days after Bout 1, and 24 h after Bout 2 to assess motor unit synchronization and recruitment thresholds. Following a single eccentric exercise session that elicited significant indicators of muscle damage, we found a 57% increase in motor unit synchronization 7 days later compared with before exercise, despite the recovery of maximal strength, soreness, and relaxed elbow-joint angle at this time. Furthermore, a second bout of the same eccentric exercise resulted in reduced indicators of muscle damage and a decline in the strength of motor unit synchronization (24 h after Bout 2) toward levels observed before both exercise sessions. In contrast, no changes in motor unit recruitment thresholds were observed 7 days after Bout 1 or 24 h after Bout 2 compared with before exercise. The increased motor unit synchronization 7 days after a single eccentric exercise session provides new evidence of changes in motor unit activity during the putative repair and regeneration phase following eccentric muscle damage.
The timing of associative memory formation: frontal lobe and anterior medial temporal lobe activity at associative binding predicts memory
Authors: Hales J. B. , Brewer J. B.
Published: January 2011

The process of associating items encountered over time and across variable time delays is fundamental for creating memories in daily life, such as for stories and episodes. Forming associative memory for temporally discontiguous items involves medial temporal lobe structures and additional neocortical processing regions, including prefrontal cortex, parietal lobe, and lateral occipital regions. However, most prior memory studies, using concurrently presented stimuli, have failed to examine the temporal aspect of successful associative memory formation to identify when activity in these brain regions is predictive of associative memory formation. In the current study, functional MRI data were acquired while subjects were shown pairs of sequentially presented visual images with a fixed interitem delay within pairs. This design allowed the entire time course of the trial to be analyzed, starting from onset of the first item, across the 5.5-s delay period, and through offset of the second item. Subjects then completed a postscan recognition test for the items and associations they encoded during the scan and their confidence for each. After controlling for item-memory strength, we isolated brain regions selectively involved in associative encoding. Consistent with prior findings, increased regional activity predicting subsequent associative memory success was found in anterior medial temporal lobe regions of left perirhinal and entorhinal cortices and in left prefrontal cortex and lateral occipital regions. The temporal separation within each pair, however, allowed extension of these findings by isolating the timing of regional involvement, showing that increased response in these regions occurs during binding but not during maintenance.
Comparative Risk Aversion under Background Risk Revisited
Authors: Ohnishi Masamitsu , Osaki Yusuke
Published: January 2011

This paper determines a new sufficient condition of the (von Neumann‐Morgenstern) utility function that preserves comparative risk aversion under
background risk. It is the single crossing condition of risk aversion. Because
this condition requires monotonicity in the local sense, it may satisfy the
U‐shaped risk aversion observed in the recent empirical literature.
Intrathoracic Caecal Perforation Presenting as Dyspnea
Authors: Granier Vincent , Coche Emmanuel , Hantson Philippe , Thoma Maximilien
Published: January 2011

Introduction. Bochdalek hernia is a congenital defect of the diaphragm that is usually diagnosed in the neonatal period and incidentally in asymptomatic adults. Small bowel incarceration in a right-sided Bochdalek hernia is exceptional for an adult.Case Presentation. A 54-year-old woman was admitted for acute dyspnea, tachycardia, hypotension, and fever. Five days before, she had been experiencing an episode of diffuse abdominal pain. The admission chest X-ray was interpreted as right pleural effusion and pneumothorax with left mediastinal shift. Chest tube drainage was purulent. The thoracoabdominal CT examination suspected an intestinal incarceration through a right diaphragmatic defect. At laparotomy, a right-sided Bochdalek hernia was confirmed with a complete necrosis of the incarcerated caecum. Ileocaecal resection was performed, but the patient died from delayed septic complications.Conclusion. Intrathoracic perforation of the caecum is a rare occurrence; delayed diagnosis due to misleading initial symptoms may lead to severe complications and poor prognosis.
Trisomy 14 as a Sole Chromosome Abnormality Is Associated with Older Age, a Heterogenous Group of Myeloid Neoplasms with Dysplasia, and a Wide Spectrum of Disease Progression
Authors: Cui Wei , Bueso-Ramos Carlos E. , Yin C. Cameron , Sun Jianlan , Chen Su , Muddasani Ramya , Lu Gary
Published: January 2011

Trisomy 14 is a rare recurrent cytogenetic abnormality in myeloid neoplasms; however, its clinicopathologic features have not been well described. We report the clinicopathologic, immunophenotypic, and molecular genetic features of 16 cases of myeloid neoplasms with isolated trisomy 14. Our results show that cases with isolated trisomy 14 encompass a heterogenous group of myeloid neoplasms including myelodysplastic syndrome (MDS, 44%), myelodysplastic/myeloproliferative neoplasms (31%), and acute myeloid leukemia (25%). The patients are usually elder (median age 71 years), and there is a male predominance (82%). Multilineage dysplasia is noted in all cases. Oncogenic mutations of genes involved in cell proliferation and/or survival rarely occur. Compared with cases of MDS with diploid karyotype, patients of MDS with isolated trisomy 14 demonstrate a similar overall survival and rate of leukemia transformation.