bluuebunny/crossref_metadata_2025 huggingface dataset:
Controllable synthesis of high surface area Nb2O5 nanowires by polyamide
Authors: Zhang Zhenwei , Zhang Jintao , Chuanjun Yue , Jianheng Hu , Shifu Zheng
Published: September 2017

A high surface area Nb2O5 nanowire material was synthesised by the soft chemical method using polyamide (Pebax) as a structure direct agent and isopropanol as a solvent. The crystal size and BET surface area of Nb2O5 were tuned by the quantity of Pebax. The surface area can reach up to 402 m2 g−1, which is higher than the reported value in the literature. Adsorption properties and photocatalyst properties were tested using methylene blue (MB), neural red (NR), Rhodamine B (RhB), and methyl orange (MO). The results show that MB and NR exhibit a good adsorption performance, the molecular structures of the dyes have a tricyclic aromatic ring and several amine groups can improve their adsorption properties. In a photocatalyst reaction, Nb2O5 has a selective activity for dye degradation. After 2 h of ultraviolet irradiation, the degradation rate of MB is about 91.9%, but the NR was degraded little.
Platelets as Modulators of Liver Diseases
Authors: Luyendyk James , Lisman Ton
Published: September 2017

Platelets are key players in thrombosis and hemostasis. Alterations in platelet count and function are common in liver disease, and may contribute to bleeding or thrombotic complications in liver diseases and during liver surgery. In addition to their hemostatic function, platelets may modulate liver diseases by mechanisms that are incompletely understood. Here, we present clinical evidence for a role of platelets in the progression of chronic and acute liver diseases, including cirrhosis, acute liver failure, and hepatocellular carcinoma. We also present clinical evidence that platelets promote liver regeneration following partial liver resection. Subsequently, we summarize studies in experimental animal models that support these clinical observations, and also highlight studies that are in contrast with clinical observations. The combined results of clinical and experimental studies suggest that platelets may be a therapeutic target in the treatment of liver injury and repair, but the gaps in our understanding of mechanisms involved in platelet-mediated modulation of liver diseases call for caution in clinical application of these findings.
Getting Started: A Social Media Primer
Authors: Ferguson Dalya , Kao Lillian
Published: September 2017

Social media use has increased both in the general public and in the surgical profession. A variety of social media platforms have been used, with Twitter being one of the most common and interactive platforms. Common uses by surgeons and scientists for social media include dissemination of information, information exchange, education, research recruitment, community consultation for clinical trials, and hospital or surgeon ratings. As social media use increases, a new language as well as metrics has been developed to track impact and reach of research incorporating social media platforms. All surgeons should be encouraged to familiarize themselves with social media, regardless of whether or not they choose to actively engage in it.
How Can Social Media Get Us in Trouble?
Authors: Batra Rishi , Langenfeld Sean
Published: September 2017

When utilized properly, social media offers several personal and professional benefits for the practicing surgeon, including peer networking, education, e-mentorship, marketing, recruitment, and patient outreach. However, unprofessional online behavior is common among surgeons, and this improper use of social media can be quite dangerous. This article reviews the dangers of social media and illustrates this with examples of unprofessional behavior and the associated consequences. It also provides recommendations for maintaining a professional and productive online persona. Surgeons must understand the various social media platforms and their target audience while upholding online professionalism at all times.
The Complications of Vascular Access in Hemodialysis
Authors: Masud Avais , Costanzo Eric , Zuckerman Roman , Asif Arif
Published: September 2017

Complications related to hemodialysis vascular access continue to have a major impact on morbidity and mortality. Vascular access dysfunction is the single most important factor that determines the quality of dialysis treatment. Vascular access stenosis is a common complication that develops in a great majority of patients with an arteriovenous access and leads to access dysfunction. By restricting luminal diameter, this complication leads to a reduction in blood flow and places the access at risk for thrombosis. Similarly, the development of catheter-related fibroepithelial sheath also causes catheter dysfunction with its detrimental effects on blood flow. In this article, we discuss the most common complications associated with dialysis access and provide therapeutic options to manage these problems.
Estudio comparativo de reconstrucción de ligamento cruzado anterior con y sin lesiones condrales; resultados funcionales a largo plazo
Authors: Figueroa David , Arellano Sergio , Schmidt-Hebbel Andrés , Gomez Carlos , Calvo Rafael , Vaisman Alex
Published: September 2017

Introducción La lesión del ligamento cruzado anterior (LCA), es una patología frecuente, y el éxito de la reconstrucción depende de diversos factores, tales como la técnica quirúrgica empleada, la edad del paciente, índice masa corporal, nivel de actividad y lesiones asociadas. El objetivo de este estudio es comparar los resultados funcionales a largo plazo de pacientes con lesiones condrales tratadas y sin lesiones condrales sometidos a la reconstrucción de LCA (RLCA), con autoinjerto semitendinoso-gracilis (ST-G).

Materiales y Métodos Estudio analítico retrospectivo. Cuarenta y nueve pacientes (34 hombres y 15 mujeres), fueron sometidos a la RLCA con autoinjerto ST-G. Se compararon dos grupos. Grupo RLCA + LC: 24 pacientes con lesiones condrales ICRS grado III y IV tratadas en el mismo acto quirúrgico y grupo RLCA: 25 pacientes sin lesiones condrales concomitantes. Las edades promedio fueron de 32 y 28 años en cada grupo respectivamente. La funcionalidad de los pacientes a largo plazo fue evaluada con el test de Lysholm, IKDC y retorno deportivo. Se compararon los promedios de los scores funcionales según cada grupo con Test de Mann-Whitney. La asociación entre ambos grupos y el retorno deportivo se analizó con Test de Chi2. Los análisis estadísticos se realizaron con Stata IC 13.

Resultados El seguimiento promedio fue de 106,8 meses (rango: 86–125). Los resultados funcionales obtenidos al comparar el grupo RLCA + LC vs grupo RLCA fueron significativamente peores en el primero, con un promedio del score de Lysholm de 84,87 vs 94,52 (p = 0.0001) e IKDC de 84,43 vs 92,08 (p = 0,004), respectivamente. El retorno deportivo de cada grupo fue de 70,8% y 88% (p = 0,136).

Conclusión La funcionalidad a largo plazo de los pacientes con una RLCA y que tengan alguna LC profunda tratada concomitante, es significativamente inferior que aquellos pacientes con RLCA aislada. No existen diferencias significativas en el porcentaje de retorno deportivo entre ambos grupos. Nivel de evidencia: tipo IV
Interobserver Variation of the Bolus-and-Burst Method for Pancreatic Perfusion with Dynamic – Contrast-Enhanced Ultrasound
Authors: Stangeland Marcus , Engjom Trond , Mezl Martin , Jirik Radovan , Gilja Odd , Dimcevski Georg , Nylund Kim
Published: September 2017

Purpose Dynamic contrast-enhanced ultrasound (DCE-US) can be used for calculating organ perfusion. By combining bolus injection with burst replenishment, the actual mean transit time (MTT) can be estimated. Blood volume (BV) can be obtained by scaling the data to a vessel on the imaging plane. The study aim was to test interobserver agreement for repeated recordings using the same ultrasound scanner and agreement between results on two different scanner systems.

Materials and Methods Ten patients under evaluation for exocrine pancreatic failure were included. Each patient was scanned two times on a GE Logiq E9 scanner, by two different observers, and once on a Philips IU22 scanner, after a bolus of 1.5 ml Sonovue. A 60-second recording of contrast enhancement was performed before the burst and the scan continued for another 30 s for reperfusion. We performed data analysis using MATLAB-based DCE-US software. An artery in the same depth as the region of interest (ROI) was used for scaling. The measurements were compared using the intraclass correlation coefficient (ICC) and Bland Altman plots.

Results The interobserver agreement on the Logiq E9 for MTT (ICC=0.83, confidence interval (CI) 0.46–0.96) was excellent. There was poor agreement for MTT between the Logiq E9 and the IU22 (ICC=−0.084, CI −0.68–0.58). The interobserver agreement for blood volume measurements was excellent on the Logiq E9 (ICC=0.9286, CI 0.7250–0.98) and between scanners (ICC=0.86, CI=0.50–0.97).

Conclusion Interobserver agreement was excellent using the same scanner for both parameters and between scanners for BV, but the comparison between two scanners did not yield acceptable agreement for MTT. This was probably due to incomplete bursting of bubbles in some of the recordings on the IU22.
Der G-Score – ein Screeninginstrument zur Erfassung der subjektiven körperlichen Gesundheit
Authors: Schneider Juliana , Zenger Markus , Brähler Elmar , Stöbel-Richter Yve , Berth Hendrik
Published: September 2017

Einleitung Die Erfassung der subjektiv eingeschätzten körperlichen Gesundheit ist wichtig im Kontext vieler klinischer und Forschungsfragestellungen. In der vorliegenden Arbeit wird eine Untersuchung der psychometrischen Kriterien des G-Scores, einem 4 Items umfassenden Screeninginstrument zur Selbstbeurteilung der körperlichen Gesundheit, vorgenommen.

Material und Methoden Es erfolgten Einschätzungen der Objektivität, der Validität und der Reliabilität, eine Itemanalyse und die Bestimmung eines geeigneten Cut-Off-Wertes zur Unterscheidung gesunder von körperlich auffälligen Personen anhand von Daten der Sächsischen Längsschnittstudie 1998–2013 (N=324–417 Personen der Normalbevölkerung).

Ergebnisse Die Objektivität des G-Scores kann aufgrund seiner Standardisierung als gegeben angesehen werden. Als Cut-Off-Wert zur Unterscheidung körperlich auffälliger von gesunden Personen wird ein G-Score von 4 vorgeschlagen. Die Inhaltsvalidität ist anhand des a posteriori definierten Konstruktes der körperlichen Gesundheit als gut einzuschätzen. Die Korrelationen mit assoziierten und nicht-assoziierten Konstrukten sprechen für einen Zusammenhang körperlicher mit psychischen Beschwerden. Die prädiktive Validität des Instruments ist gut. Die Reliabilitätsanalysen ergeben Werte im zufriedenstellenden Bereich. Dies spricht für eine hohe Änderungssensitivität des erfassten Konstrukts.

Diskussion und Schlussfolgerungen Aufgrund der Ergebnisse empfiehlt sich der G-Score für den Einsatz als Screeninginstrument im Forschungsbereich. Es sollten weitere psychometrische Untersuchungen des G-Scores an einer bevölkerungsrepräsentativen Stichprobe und mit objektiven Vergleichsdaten durchgeführt werden.
Symptoms Of Common Mental Disorders In Professional Rugby: An International Observational Descriptive Study
Authors: Gouttebarge Vincent , Hopley Phil , Kerkhoffs Gino , Verhagen Evert , Viljoen Wayne , Wylleman Paul , Lambert Mike
Published: September 2017

The aim of the study was to determine the prevalence of symptoms of common mental disorders among professional rugby players across countries. A cross-sectional analysis of the baseline questionnaires from an ongoing prospective cohort study was conducted. Nine national players’ associations and three rugby unions distributed questionnaires based on validated scales for assessing symptoms of common mental disorders. Among the whole study sample (N=990; overall response rate of 28%), prevalence (4-week) of symptoms of common mental disorders ranged from 15% for adverse alcohol use to 30% for anxiety/depression. These findings support the prevalence rates of symptoms of common mental disorders found in previous studies among professional (i. e., elite) athletes across other sports, and suggestions can be made that the prevalence of symptoms of anxiety/depression seems slightly higher in professional rugby than in other general/occupational populations. Awareness of the prevalence of symptoms of common mental disorders should be improved in international rugby, and an interdisciplinary approach including psychological attention should be fostered in the medical care of professional rugby players. Adequate supportive measures to enhance awareness and psychological resilience would lead not only to improved health and quality of life among rugby players but arguably to enhanced performance in rugby.
Physical activity during video capsule endoscopy correlates with shorter bowel transit time
Authors: Stanich Peter , Peck Joshua , Murphy Christopher , Porter Kyle , Meyer Marty
Published: September 2017

Background and study aim Video capsule endoscopy (VCE) is limited by reliance on bowel motility for propulsion, and lack of physical activity has been proposed as a cause of incomplete studies. Our aim was to prospectively investigate the association between physical activity and VCE bowel transit.

Patients and methods Ambulatory outpatients receiving VCE were eligible for the study. A pedometer was attached at the time of VCE ingestion and step count was recorded at the end of the procedure. VCE completion was assessed by logistic regression models, which included step count (500 steps as one unit). Total transit time was analyzed by Cox proportional hazards models. The hazard ratios (HR) with 95 % confidence interval (CI) indicated the “hazard” of completion, such that HRs > 1 indicated a reduced transit time.

Results A total of 100 patients were included. VCE was completed in 93 patients (93 %). The median step count was 2782 steps. Step count was not significantly associated with VCE completion (odds ratio 1.45, 95 %CI 0.84, 2.49). Pedometer step count was significantly associated with shorter total, gastric, and small-bowel transit times (HR 1.09, 95 %CI 1.03, 1.16; HR 1.05, 95 %CI 1.00, 1.11; HR 1.07, 95 %CI 1.01, 1.14, respectively). Higher body mass index (BMI) was significantly associated with VCE completion (HR 1.87, 95 %CI 1.18, 2.97) and shorter bowel transit times (HR 1.05, 95 %CI 1.02, 1.08).

Conclusions Increased physical activity during outpatient VCE was associated with shorter bowel transit times but not with study completion. In addition, BMI was a previously unreported clinical characteristic associated with VCE completion and should be included as a variable of interest in future studies.
The PI3K/Akt1-FoxO1 Translocation Pathway Mediates EXf Effects on NIT-1 Cell Survival
Authors: Hou Guo-jiang , Li Cai-na , Huan Yi , Liu Shuai-nan , Liu Quan , Liu Min-zhi , Shen Zhu-fang
Published: September 2017

EXf, a glucagon-like peptide 1 (GLP-1) receptor agonist, stimulates β-cell proliferation and reduces apoptosis in diabetic animal models, but the underlying mechanisms are not fully understood. We constructed a FoxO1-GFP fusion protein expression plasmid and transiently transfected it into NIT-1 cells to investigate whether FoxO1 mediates EXf effects on NIT-1 cell survival. Our results showed that EXf could increase cell viability by inhibiting apoptosis and stimulating proliferation, and it could also promote the translocation of the FoxO1-GFP fusion protein from the nucleus to the cytoplasm in NIT-1 cells. However, the above effects of EXf were suppressed by the inhibitor of PI3K. Comparative transcription analysis showed up-regulation of igf-1r, irs-2, pI3k, akt1 and pdx-1 in NIT-1 cells after EXf treatment. Moreover, the up-regulation of PI3K and phosphorylation of Akt1 upon EXf treatment was confirmed by Western blot, both phenomena were abrogated by wortmannin, an inhibitor of PI3K. In summary, FoxO1 may mediate the effects of EXf on NIT-1 cell survival by activating the PI3K/Akt1 pathway.
Lactobacilus Delbrueckii subsp. Bulgaricus Modulates the Secretion of Th1/Th2 and Treg Cell-Related Cytokines by PBMCs from Patients with Atopic Dermatitis
Authors: Sheikhi Abdolkarim , Giti Hojjat , Heibor Mohammad , Jafarzadeh Abdollah , Shakerian Mansour , Baharifar Narges , Niruzad Fereidon , Moghaddam Ali , Kokhaei Parviz , Baghaeifar Mohammad
Published: September 2017

Background Atopic dermatitis (AD) is an inflammatory skin disease which may be due to the imbalance between Th1-, Th2 and Treg cell-related immune responses. Evidences suggest that appropriate stimulation with probiotics may correct the skewed immune response in children with AD. The aim was to determine the effects of the yogurt culture lactobacillus Bulgaricus on the secretion of Th1/Th2/Treg type cytokines by PBMCs from children with AD.

Methods L. Bulgaricus was cultivated on MRS broth. The PBMCs from 20 children with AD were separated by Ficoll-Hypaque centrifugation and co-cultured with different concentrations of UV killed bacteria in RPMI-1640 plus 10% FCS for 48/72 h. The levels of IL-10, IL-4, IL-12 and IFN-γ were measured in supernatant of PBMCs by ELISA.

Results L. Bulgaricus significantly up-regulated the secretion of IL-10, IL-12 and IFN-γ, whereas decreased the secretion of IL-4 by PBMCs at both incubation times 48 h/72 h and both bacteria:PBMCs ratios 100:1/50:1, compared to control (p<0.05). There were no significant differences between incubation times 48 h and 72 h regarding the secretion levels of IL-12, IFN-γ and IL-4. However, the secretion of IL-10 by L. Bulgaricus-stimulated PBMCs at incubation time 72 h and in the presence of bacteria:PBMCs ratio 100:1 was significantly higher than in incubation time 48 h and in the presence of bacteria:PBMCs ratio 50:1 (P<0.000 and P<0.00, respectively).

Conclusion These data show that L. Bulgaricus may modulate the secretion of Th1-, Th2-Treg-related cytokines in AD patients. Therefore, the possible potential therapeutic of L. Bulgaricus for treatment of AD should be consider in further investigation.
Neuroanatomie des okulomotorischen Systems
Authors: Heermann Stephan
Published: September 2017

Neuroanatomische Kenntnisse erlauben dem erfahrenen Untersucher von Patienten mit Erkrankungen des Nervensystems bereits nach einer klinischen Untersuchung eine gute Topodiagnostik. Dies trifft auch auf die Elemente des Nervensystems zu, die an der Steuerung der Augen beteiligt sind. In diesem Beitrag sind neuroanatomische Grundlagen zusammengetragen, welche die Okulomotorik betreffen. Der Beitrag soll dazu dienen, den Aufbau und die Funktion dieses Systems zu verstehen und pathologische Veränderungen bestimmten Läsionsorten zuordnen zu können. Nach einer kurzen Einführung werden zunächst die einzelnen Elemente, wie die extraokulären Muskeln und die sie versorgenden Nerven, vorgestellt. Der folgende Teil dieses Beitrags beschäftigt sich schließlich mit der Kontrolle der Augenbewegung, mit unterschiedlichen Bereichen des zentralen Nervensystems (ZNS), die hierbei beteiligt sind, und mit spezifischen Bewegungsmustern. Darüber hinaus soll dieser Beitrag aber auch einen kurzen Überblick über die Steuerung der inneren Augenmuskeln liefern.
Higher adenoma detection rate with the endocuff: a randomized trial
Authors: González-Fernández Coty , García-Rangel David , Aguilar-Olivos Nancy , Barreto-Zúñiga Rafael , Romano-Munive Adriana , Grajales-Figueroa Guido , Zamora-Nava Luis , Téllez-Avila Félix
Published: September 2017

Background and study aim Different techniques have been introduced to improve the endoscopist’s view and enhance the detection of polyps. The endocuff is a polymer sleeve cap that is connected to the tip of the colonoscope in order to improve visualization of the mucosa during colonoscopy. The aim of the study was to compare adenoma detection rates (ADR) of endocuff-assisted colonoscopy and conventional colonoscopy.

Patients and methods Patients 50 years or older were randomized into two groups: an endocuff-assisted colonoscopy group and a conventional colonoscopy group without the endocuff.

Results A total of 337 patients were included: 174 in the endocuff group and 163 in the conventional group. The median age was 61 years (interquartile range 55 – 70 years), and 74 % were women. The ADR was higher in the endocuff group than in the conventional group (22.4 % vs. 13.5 %; P = 0.02). The mean number of adenomas was 0.30 (SD 0.25) in the endocuff group and 0.21 (SD 0.26) in the conventional group (P  = 0.02). The rate of ileal intubation was lower in the endocuff group (73 % vs. 87 %; P < 0.001). No serious adverse events occurred with the use of the endocuff.

Conclusions Endocuff colonoscopy achieved a greater ADR than conventional colonoscopy.

Trial registered at ClinicalTrials.gov (NTC02387593).
Application of Spray Drying Technique for Flowability enhancement of Divalproex Sodium
Authors: Ghanbarzadeh Saeed , Valizadeh Hadi , Yaqoubi Shadi , Asdagh Arash , Hamishehkar Hamed
Published: September 2017

Background Tablets and capsules are the most accepted and widely used solid dosage forms in the medical therapy. Flow property of the powders is playing a key role in the various pharmaceutical fields especially in the fomulation of tablets and capsules. The high hygroscopic crystalline structure of anhydrous Divalproex sodium (DVX) makes it to be appear as waxy white ﬂakes with almost no powder flowability which cause serious problems during the tabletting and capsule filling procedures.

Purpose The main objective of this study was to improve the flowability of DVX powder.

Methods DVX was mixed with mannitol or lactos in different ratios, dissolved in water and differet binary mixtures of ethanol:water, and finally spray dried with different spray drying conditions. Particle size and powders morphology were assessed by Scanning Electron Microscopy (SEM). The poweder flowability was assessed by measurmet of Hausner ratio (HR), Carr’s index (CI) and angle of repose (AOR) indexes. Furthermore, the content uniformity of DVX in spray-dried powders was determined by using a validated HPLC technique.

Results The results showed that spray drying technique improved DVX flowability by forming spherical particles with narrow size distribution AOR value of DVX was decrease from not flowable to 36.1° in spray dried solid dispersion indicating the improvmet of powder flowability from very poor to fair/good condition.

Conclusion Findings suggest that the spray drying technique improves DVX flowability and may pave the way for improvement in the tabletting procedure of DVX.
Insertion of percutaneous endoscopic gastrostomy tubes with jejunal extensions using the “wedge” technique: a novel method to prevent retrograde tube migration into the stomach
Authors: Sey Michael , Gregor Hannah , Gregor Jamie , Yan Brian
Published: September 2017

Background and study aim In percutaneous endoscopic gastrostomy (PEG) with jejunal extension (PEGJ) procedures, retrograde migration of the jejunal extension tube into the stomach during endoscope withdrawal is a frustrating problem. We describe the novel “wedge” technique for inserting the jejunal extension tube, utilizing single-balloon enteroscopy to anchor it in place.

Patients and methods Prospective 1-year study of consecutive patients undergoing PEGJ insertion at a single tertiary care center. The primary outcome was number of pyloric intubations required to place the jejunal extension tube. Secondary outcomes included success rate, time, and complications related to jejunal extension tube insertion.

Results 17 patients underwent the procedure. The jejunal extension tube was inserted at the first attempt in 15 patients (88.2 %) and 2 required another pyloric intubation. Abdominal X-ray showed that all PEGJ tubes were successfully seated in the proximal jejunum. The mean (SD) time required for jejunal extension insertion was 16.9 (8.6) minutes. Two adverse events occurred due to PEG insertion although none were related to the jejunal extension insertion itself.

Conclusions: The “wedge” technique is an effective and easy method for inserting a jejunal extension tube after PEG insertion.
Balanced Coagonist of GLP-1 and Glucagon Receptors Corrects Dyslipidemia by Improving FGF21 Sensitivity in Hamster Model
Authors: Patel Vishal , Joharapurkar Amit , Kshirsagar Samadhan , Patel Hiren , Pandey Dheerendra , Patel Dipam , Sutariya Brijesh , Patel Maulik , Bahekar Rajesh , Jain Mukul
Published: September 2017

Hyperlipidemia is often associated with obesity and diabetes, and can lead to serious complications like atherosclerosis and fatty liver disease. Coagonist of GLP-1 and glucagon receptors is a therapy under clinical investigation for treatment of obesity and diabetes. In this study, we have characterized the mechanism of hypolipidemic effect of a balanced coagonist using high cholesterol-fed hamsters. Tyloxapol-induced hypertriglyceridemia, lipolysis in adipose tissue, and bile homeostasis were assessed after repeated dose treatment of the coagonist of GLP-1 and glucagon receptors (Aib2 C24 chimera 2, SC). Antagonists of GLP-1, glucagon, and FGF21 receptors were coadministered, and FGF21 sensitivity was determined in liver and adipose tissue. Repeated dose treatment of coagonist reduced cholesterol and increased FGF21 in blood and liver. Coagonist treatment reduced hepatic triglyceride secretion, increased lipolysis and reduced body weight. Antagonism of GLP-1 and glucagon receptors partially blocked the effect of the coagonist on lipid metabolism in circulation and liver, while FGF21 receptor antagonist completely abolished it. Glucagon and GLP-1 receptors antagonists blocked the action of coagonist on cholesterol excretion and bile flow in liver, but FGF21 antagonist was not effective. Treatment with the coagonist increased expression of FGF21, FGF21R and cofactor ßKlotho in liver and adipose. In conclusion, coagonist of GLP-1 and glucagon receptors improved lipid metabolism in liver of dyslipidemic hamsters. This effect is partially mediated by GLP-1 and glucagon receptors, and the improved FGF21 sensitivity could be the mechanism of hypolipidemic action of the coagonist of GLP-1/glucagon receptors.
Enhanced green fluorescent protein in optofluidic Fabry-Perot microcavity to detect laser induced temperature changes in a bacterial culture
Authors: Lahoz F. , Martín I. R. , Walo D. , Freire R. , Gil-Rostra J. , Yubero F. , Gonzalez-Elipe A. R.
Published: September 2017

Thermal therapy using laser sources can be used in combination with other cancer therapies to eliminate tumors. However, high precision temperature control is required to avoid damage in healthy surrounding tissues. Therefore, in order to detect laser induced temperature changes, we have used the fluorescence signal of the enhanced Green Fluorescent Protein (eGFP) over-expressed in an E. coli bacterial culture. For that purpose, the bacteria expressing eGFP are injected in a Fabry-Perot (FP) optofluidic planar microcavity. In order to locally heat the bacterial culture, external infrared or ultraviolet lasers were used. Shifts in the wavelengths of the resonant FP modes are used to determine the temperature increase as a function of the heating laser pump power. Laser induced local temperature increments up to 6–7 °C were measured. These results show a relatively easy way to measure laser induced local temperature changes using a FP microcavity and using eGFP as a molecular probe instead of external nanoparticles, which could damage/alter the cell. Therefore, we believe that this approach can be of interest for the study of thermal effects in laser induced thermal therapies.
Error modeling and calibration of a 4ṞRR redundant positioning system
Authors: Yao Sheng , Zhang Xianmin , Yu Jing , Zhu Benliang
Published: September 2017

Using the macro-micro combination positioning system for nanomanipulating can fulfill the requirements of large workspace, high precision and multi-degrees of freedom. As a macro part of the macro-micro combination positioning system, a redundantly actuated three degrees-of-freedom (DOF) parallel kinematic mechanism (4ṞRR) with a directly driven system is studied in this paper. Firstly, the error sensitivity of the 4ṞRR planar parallel mechanism is analyzed with global errors sensitive index (GESI) based on the error model of the positioning system. Then, a novel and practical calibration method combined with an error compensation strategy is proposed for the 4ṞRR positioning system. Finally, in order to verify the proposed method, a series of experiments are conducted with the laser measurement system in creditable conditions, and the data are illustrated for comparisons. The experimental results show that the positioning accuracy of the 4ṞRR positioning system is improved, and the performances of the end-effector are enhanced based on the proposed method.
Growth of Ca, Zr co-doped BaTiO3 lead-free ferroelectric single crystal and its room-temperature piezoelectricity
Authors: Liu Donglin , Shim Jaeshik , Sun Yue , Li Qiang , Yan Qingfen
Published: September 2017

Lead-free Ca, Zr co-doped BaTiO3 (BCZT) single crystal with a dimension up to 2mm×2mm×2mm was grown by a spontaneous nucleation technique using KF as the flux. The composition of the studied single crystal was defined to be Ba0.798Ca0.202Zr0.006Ti0.994O3, corresponding to a tetragonal phase at room temperature. The <001> oriented single crystal exhibited a quasi-static piezoelectric constant of approximately 232 pC/N. The effective piezoelectric coefficient d33* of the single domain crystal obtained under a unipolar electric field of 35 kV/cm was 179 pm/V. Rayleigh analysis was used to identify the intrinsic and extrinsic contributions to the room-temperature piezoelectricity of BCZT single crystal. The extrinsic contribution was estimated up to 40% due to the irreversible domain wall movement. Furthermore a sixth-order polynomial of Landau expansion was employed to analyze the intrinsic contribution to piezoelectricity of BCZT single crystal. The large energy barriers inhibited polarization rotations, leading to the relatively low piezoelectricity.
Influence of the particle size on polarization-based range-gated imaging in turbid media
Authors: Tian Heng , Zhu Jingping , Tan Shuwen , Zhang Yunyao , Hou Xun
Published: September 2017

The influence of size of the scatterer on the image contrast for polarization-based range-gated imaging in turbid media is investigated here by Monte Carlo method. Circularly polarized light would be more efficient to eliminate the noise photons for both the isotropic medium as well as the anisotropic medium, as compared with linearly polarized light. The improvement in contrast is pronounced for isotropic medium using either linear or circular polarization. The plausible explanations for these observations are also presented.
Renormalization of SU(2) Yang–Mills theory with flow equations
Authors: Efremov Alexander N. , Guida Riccardo , Kopper Christoph
Published: September 2017

We give a proof of perturbative renormalizability of SU(2) Yang–Mills theory in four-dimensional Euclidean space which is based on the flow equations of the renormalization group. The main motivation is to present a proof which does not make appear mathematically undefined objects (as, for example, dimensionally regularized generating functionals), which permits to parametrize the theory in terms of physical renormalization conditions, and which allows to control the singularities of the correlation functions of the theory in the infrared domain. Thus a large part of the proof is dedicated to bounds on massless correlation functions.
A proposal of Fourier-Bessel expansion with optimized ensembles of bases to analyse two dimensional image
Authors: Yamasaki K. , Fujisawa A. , Nagashima Y.
Published: September 2017

It is a critical issue to find the best set of fitting function bases in mode structural analysis of two dimensional images like plasma emission profiles. The paper proposes a method to optimize a set of the bases in the case of Fourier-Bessel function series, using their orthonormal property, for more efficient and precise analysis. The method is applied on a tomography image of plasma emission obtained with the Maximum-likelihood expectation maximization method in a linear cylindrical device. The result demonstrates the excellency of the method that realizes the smaller residual error and minimum Akaike information criterion using smaller number of fitting function bases.
Position calibration of a 3-DOF hand-controller with hybrid structure
Authors: Zhu Chengcheng , Song Aiguo
Published: September 2017

A hand-controller is a human-robot interactive device, which measures the 3-DOF (Degree of Freedom) position of the human hand and sends it as a command to control robot movement. The device also receives 3-DOF force feedback from the robot and applies it to the human hand. Thus, the precision of 3-DOF position measurements is a key performance factor for hand-controllers. However, when using a hybrid type 3-DOF hand controller, various errors occur and are considered originating from machining and assembly variations within the device. This paper presents a calibration method to improve the position tracking accuracy of hybrid type hand-controllers by determining the actual size of the hand-controller parts. By re-measuring and re-calibrating this kind of hand-controller, the actual size of the key parts that cause errors is determined. Modifying the formula parameters with the actual sizes, which are obtained in the calibrating process, improves the end position tracking accuracy of the device.
The classical dynamic symmetry for the Sp(1)-Kepler problems
Authors: Bouarroudj Sofiane , Meng Guowu
Published: September 2017

A Poisson realization of the simple real Lie algebra so*(4n) on the phase space of each Sp(1)-Kepler problem is exhibited. As a consequence, one obtains the Laplace-Runge-Lenz vector for each classical Sp(1)-Kepler problem. The verification of these Poisson realizations is greatly simplified via an idea of Weinstein. The totality of these Poisson realizations is shown to be equivalent to the canonical Poisson realization of so*(4n) on the Poisson manifold T*H*n/Sp(1). (Here H*n≔Hn\{0} and the Hamiltonian action of Sp(1) on T*H*n is induced from the natural right action of Sp(1) on H*n.)
Attracting subspaces in a hyper-spherical representation of autonomous dynamical systems
Authors: Ceccato Alessandro , Nicolini Paolo , Frezzato Diego
Published: September 2017

In this work, we focus on the possibility to recast the ordinary differential equations (ODEs) governing the evolution of deterministic autonomous dynamical systems (conservative or damped and generally non-linear) into a parameter-free universal format. We term such a representation “hyper-spherical” since the new variables are a “radial” norm having physical units of inverse-of-time and a normalized “state vector” with (possibly complex-valued) dimensionless components. Here we prove that while the system evolves in its physical space, the mirrored evolution in the hyper-spherical space is such that the state vector moves monotonically towards fixed “attracting subspaces” (one at a time). Correspondingly, the physical space can be split into “attractiveness regions.” We present the general concepts and provide an example of how such a transformation of ODEs can be achieved for a class of mechanical-like systems where the physical variables are a set of configurational degrees of freedom and the associated velocities in a phase-space representation. A one-dimensional case model (motion in a bi-stable potential) is adopted to illustrate the procedure.
Transmission-line resonators for the study of individual two-level tunneling systems
Authors: Brehm Jan David , Bilmes Alexander , Weiss Georg , Ustinov Alexey V. , Lisenfeld Jürgen
Published: September 2017

Parasitic two-level tunneling systems (TLS) emerge in amorphous dielectrics and constitute a serious nuisance for various microfabricated devices, where they act as a source of noise and decoherence. Here, we demonstrate a new test bed for the study of TLS in various materials which provides access to properties of individual TLS as well as their ensemble response. We terminate a superconducting transmission-line resonator with a capacitor that hosts TLS in its dielectric. By tuning TLS via applied mechanical strain, we observe the signatures of individual TLS strongly coupled to the resonator in its transmission characteristics and extract the coupling components of their dipole moments and energy relaxation rates. The strong and well-defined coupling to the TLS bath results in pronounced resonator frequency fluctuations and excess phase noise, through which we can study TLS ensemble effects such as spectral diffusion, and probe theoretical models of TLS interactions.
Obliquely propagating ion acoustic solitary structures in the presence of quantized magnetic field
Authors: Iqbal Shaukat Muzzamal
Published: September 2017

The effect of linear and nonlinear propagation of electrostatic waves have been studied in degenerate magnetoplasma taking into account the effect of electron trapping and finite temperature with quantizing magnetic field. The formation of solitary structures has been investigated by employing the small amplitude approximation both for fully and partially degenerate quantum plasma. It is observed that the inclusion of quantizing magnetic field significantly affects the propagation characteristics of the solitary wave. Importantly, the Zakharov-Kuznetsov equation under consideration has been found to allow the formation of compressive solitary structures only. The present investigation may be beneficial to understand the propagation of nonlinear electrostatic structures in dense astrophysical environments such as those found in white dwarfs.
Novel functionalities of hybrid paper-polymer centrifugal devices for assay performance enhancement
Authors: Wiederoder M. S. , Smith S. , Madzivhandila P. , Mager D. , Moodley K. , DeVoe D. L. , Land K. J.
Published: September 2017

The presented work demonstrates novel functionalities of hybrid paper-polymer centrifugal devices for assay performance enhancement that leverage the advantages of both paper-based and centrifugal microfluidic platforms. The fluid flow is manipulated by balancing the capillary force of paper inserts with the centrifugal force generated by disc rotation to enhance the signal of a colorimetric lateral flow immunoassay for pathogenic E. coli. Low-cost centrifugation for pre-concentration of bacteria was demonstrated by sample sedimentation at high rotational speeds before supernatant removal by a paper insert via capillary force after deceleration. The live bacteria capture efficiency of the device was similar to a commercial centrifuge. This pre-concentrated sample when combined with gold nanoparticle immunoconjugate probes resulted in a detection limit that is 10× lower than a non-concentrated sample for a lateral flow immunoassay. Signal enhancement was also demonstrated through rotational speed variation to prevent the flow for on-device incubation and to reduce the flow rate, thus increasing the sample residence time for the improved capture of gold nanoparticle-bacteria complexes in an integrated paper microfluidic assay. Finally, multiple sequential steps including sample pre-concentration, filtration, incubation, target capture by an integrated paper microfluidic assay, silver enhancement and quenching, and index matching were completed within a single device. The detection limit was 105 colony forming units per ml, a 100× improvement over a similar paper-based lateral flow assay. The techniques utilize the advantages of paper-based microfluidic devices, while facilitating additional functionalities with a centrifugal microfluidic platform for detection performance enhancement in a low-cost, automated platform amenable to point-of-care environments.
Genetic disruption of ankyrin-G in adult mouse forebrain causes cortical synapse alteration and behavior reminiscent of bipolar disorder
Authors: Zhu Shanshan , Cordner Zachary A. , Xiong Jiali , Chiu Chi-Tso , Artola Arabiye , Zuo Yanning , Nelson Andrew D. , Kim Tae-Yeon , Zaika Natalya , Woolums Brian M. , Hess Evan J. , Wang Xiaofang , Chuang De-Maw , Pletnikov Mikhail M. , Jenkins Paul M. , Tamashiro Kellie L. , Ross Christopher A.
Published: September 2017

Significance

The
ANK3
gene locus has been repeatedly shown to confer risk for bipolar disorder in genome-wide association studies. We generated a mouse model with conditional disruption of
ANK3
gene in neurons in adult forebrain (Ank-G cKO). The mice showed robust behavioral phenotypes reminiscent of aspects of human mania, ameliorated by antimania drugs. Repeated stress resulted in dramatic behavioral changes between “mania-like” and “depression-like” status, reminiscent of human bipolar disorder. Histological studies imply that cortical microcircuitry alterations are involved in pathogenesis. Overall, we suggest that this Ank-G cKO mouse model recapitulates core features of human bipolar disorder, and may be useful for studying disease pathophysiology and for developing experimental therapeutics.
Structures of the peptide-modifying radical SAM enzyme SuiB elucidate the basis of substrate recognition
Authors: Davis Katherine M. , Schramma Kelsey R. , Hansen William A. , Bacik John P. , Khare Sagar D. , Seyedsayamdost Mohammad R. , Ando Nozomi
Published: September 2017

Significance

Ribosomally synthesized and posttranslationally modified peptides (RiPPs) are an important class of bioactive natural products. The tailoring enzymes involved in their biogenesis include radical (
S
-adenosylmethionine) SAM metalloenzymes, which often install unusual modifications. The structural basis for substrate recognition in these reactions remains unknown. Herein, we present the X-ray crystal structures of a radical SAM enzyme involved in RiPP biosynthesis. Our structures identify conformational changes correlated with the binding of peptide-substrate and SAM. Surprisingly, we find that the peptide-substrate is not associated with the RiPP recognition element (RRE) but rather observe key contacts to the active site and an important, previously unidentified, bridging domain. These findings reveal unanticipated roles for the RRE and additional domains during RiPP biosynthesis by radical SAM enzymes.
Universal nanodroplet branches from confining the Ouzo effect
Authors: Lu Ziyang , Schaarsberg Martin H. Klein , Zhu Xiaojue , Yeo Leslie Y. , Lohse Detlef , Zhang Xuehua
Published: September 2017

Significance

The phenomenon of spontaneous nanodroplet formation termed the “Ouzo effect” is the basis for many processes, from preparation of pharmaceutical products, to formulation of cosmetics and insecticides, to liquid–liquid microextraction. This work attempts to disentangle the effects of concentration gradients from the extrinsic mixing dynamics by spatiotemporally following the nanodroplet formation from the Ouzo effect confined in a quasi-2D geometry. We observe striking universal branch structures of the nucleating droplets under the external diffusive field, analogous to the ramification of stream networks in large scale, and the enhanced local mobility of colloidal particles driven by the concentration gradient emerging from the development of the branch patterns. We further demonstrate that these nanodroplets can be exploited for single-step nanoextraction and detection.
Cortically coordinated NREM thalamocortical oscillations play an essential, instructive role in visual system plasticity
Authors: Durkin Jaclyn , Suresh Aneesha K. , Colbath Julie , Broussard Christopher , Wu Jiaxing , Zochowski Michal , Aton Sara J.
Published: September 2017

Significance

Previous studies have demonstrated a role of state-specific neural activity in plasticity; however, a mechanism for these changes has yet to be elucidated. Here, we demonstrate that sensory response changes occur in thalamic neurons immediately following novel visual experience, but that subsequent nonrapid eye movement (NREM) oscillations are required for subsequent response changes in the primary visual cortex (V1). Consequently, we show that disruption of NREM oscillations specifically blocks sleep-dependent plasticity in V1. We conclude that following a novel sensory experience, neural activity patterns unique to NREM facilitate transfer of information from the visual thalamus to the V1, leading to adaptive response changes in V1 neurons.
Public willingness to pay for a US carbon tax and preferences for spending the revenue
Authors: Kotchen Matthew J , Turk Zachary M , Leiserowitz Anthony A
Published: September 2017

We provide evidence from a nationally representative survey on Americans’ willingness to pay (WTP) for a carbon tax, and public preferences for how potential carbon-tax revenue should be spent. The average WTP for a tax on fossil fuels that increases household energy bills is US$177 per year. This translates into an average WTP of 14% more on average for households across the United States, where energy costs differ significantly across states. Regarding the tax revenues, Americans are most in support of using the money to invest in clean energy and infrastructure. There is relatively less support for reducing income or payroll taxes, returning dividends to households, and other expenditure categories. Finally, Americans support using the tax revenues to assist displaced workers in the coal industry enough to compensate each miner nearly US$146 000 upon passage of a carbon tax.
Characteristics of Interim Deans at U.S. Medical Schools: Implications for Institutions and Individuals
Authors: Bunton Sarah A. , Sass Pamela , Sloane Rae Anne , Grigsby R. Kevin
Published: September 2017

Purpose

To provide a baseline, descriptive understanding of individuals serving as interim deans at U.S. medical schools. Over the past quarter century, roughly 9% to 16% of all medical school deans were serving as interim leaders. This research reviews demographic characteristics, how long they served, and the impact of having served on one’s likelihood of serving as a permanent dean.

Method

The Association of American Medical Colleges’ Council of Deans national database was the data source for this study. The authors reviewed counts and information by year for academic years 1989–1990 through 2014–2015 to yield a snapshot of interim dean counts. The authors analyzed data by demographic characteristics—namely, sex, race/ethnicity, degree, specialty, and years of service—and compared data with those of permanent deans. Descriptive statistics are presented.

Results

Overall, between 14 and 27 individuals served as interim deans during each academic year in this study (9%–16% of all unique individuals with a dean or interim dean appointment). Of all individuals serving as interim deans in this time frame, 88% were men (228/259) and 86% were white (222/259). The average time in the interim dean role was roughly 13 months, and a high percentage went on to serve as permanent deans (ranging from 15% to 63%).

Conclusions

The results of this study add detail to the collective understanding of these leaders in medical schools. The authors discuss how individuals and institutions can facilitate success and preparedness for an interim dean appointment.