bluuebunny/crossref_metadata_2025 huggingface dataset:
Non‐invasive fibrosis score for hepatitis delta
Authors: Lutterkort Gunnar L. , Wranke Anika , Yurdaydin Cihan , Budde Eva , Westphal Max , Lichtinghagen Ralf , Stift Judith , Bremer Birgit , Hardtke Svenja , Keskin Onur , Idilman Ramazan , Koch Armin , Manns Michael P. , Dienes Hans P. , Wedemeyer Heiner , Heidrich Benjamin
Published: July 2016

Background & Aims

Identifying advanced fibrosis in chronic hepatitis delta patients and thus in need of urgent treatment is crucial. To avoid liver biopsy, non‐invasive fibrosis scores may be helpful but have not been evaluated for chronic hepatitis delta yet.

Methods

We evaluated eight non‐invasive fibrosis scores in 100 HDV RNA‐positive patients with available central histological reading. New cut‐off values were calculated by using Receiver Operating Characteristics and Youden indexes. Predictors for the presence of ISHAK F3‐6 were revealed by t‐tests or Mann–Whitney tests.

Results

None of the tested scores had an area under the curve (AUROC) > 0.8 and performed according to our predefined requirements of a sensitivity of >80% and a positive predictive value (PPV) >90% – even after adaption. However, the ELF score was able to identify advanced fibrosis with a high sensitivity (93%) and PPV (81%), but relies on expensive extracellular matrix markers with bad availability in many endemic regions of HDV. Thus, we developed a novel non‐invasive approach and identified low cholinesterase (P=.002), low albumin (P=.041), higher gamma glutamyl transferase, as well as older age (P<.001) as predictors of fibrosis resulting in the Delta Fibrosis Score (DFS). The DFS performed with a sensitivity of 85% and PPV of 93% with an AUROC of 0.87.

Conclusions

Existing non‐invasive fibrosis scores are either impracticable or do not perform well in chronic hepatitis delta patients. However, the new Delta Fibrosis Score is the first non‐invasive fibrosis score specifically developed for chronic hepatitis delta and requires only standard parameters.
Review of the natural conditions and anthropogenic threats to the Ethiopian Rift Valley rivers and lakes
Authors: Lemma Brook , Desta Hayal
Published: July 2016

This review article considers the lakes found within the Ethiopian Rift Valley system and the rivers draining from the highlands towards them. The Ethiopian Rift Valley system extends in a north‐east–south‐west direction, bisecting the Ethiopian highlands. They differ in sizes and hydrological and hydrogeological settings. The lakes support a variety of flora and fauna, mainly fishes, reptiles, birds and mammals. The lakes and their feeder rivers, however, are currently being subjected to more human use pressure than previously experienced, attributable mainly to water abstractions for irrigation, household water supply and industrial activities in the catchments. Soil erosion, primarily attributable to the lack of soil conservation practices on farm lands, overgrazing and deforestation, along with unregulated irrigation practices, are generating large quantities of silt reaching the lakes. Improper utilization of water and land resources in the catchments, along with population growth and climate change impacts, is escalating the threats to the health of the lake and river ecosystems. As a result, some of the lakes exhibited reduced water levels and increased salinity. This article reviews the major environmental changes happening to these lakes and their feeder rivers. Visits were made to the area to update previous information while also consolidating the trends of change in the aquatic systems and the watersheds attributed to intense development practices.
Niche modelling of the Chilean recluse spider Loxosceles laeta and araneophagic spitting spider Scytodes globula and risk for loxoscelism in Chile
Authors: CANALS M. , TAUCARE‐RIOS A. , BRESCOVIT A. D. , PEÑA‐GOMEZ F. , BIZAMA G. , CANALS A. , MORENO L. , BUSTAMANTE R.
Published: July 2016

In Chile, all necrotic arachnidism is attributed to the Chilean recluse spider Loxosceles laeta (Nicolet) (Araneae: Sicariidae). It is predated by the spitting spider Scytodes globula (Nicolet) (Araneae: Scytodidae). The biology of each of these species is not well known and it is important to clarify their distributions. The aims of this study are to elucidate the variables involved in the niches of both species based on environmental and human footprint variables, and to construct geographic maps that will be useful in estimating potential distributions and in defining a map of estimated risk for loxoscelism in Chile. Loxosceles laeta was found to be associated with high temperatures and low rates of precipitation, whereas although S. globula was also associated with high temperatures, its distribution was associated with a higher level of precipitation. The main variable associated with the distribution of L. laeta was the human footprint (48.6%), which suggests that this is a highly invasive species. Similarly to other species, the distribution of L. laeta reaches its southern limit at the Los Lagos region in Chile, which coincides with high levels of precipitation and low temperatures. The potential distribution of L. laeta in Chile corresponds to the distribution of cases of loxoscelism.
Human adult neurogenesis across the ages: An immunohistochemical study
Authors: Dennis C. V. , Suh L. S. , Rodriguez M. L. , Kril J. J. , Sutherland G. T.
Published: July 2016

Aims

Neurogenesis in the postnatal human brain occurs in two neurogenic niches; the subventricular zone (SVZ) in the wall of the lateral ventricles and the subgranular zone (SGZ) of the hippocampus. The extent to which this physiological process continues into adulthood is an area of ongoing research. This study aimed to characterize markers of cell proliferation and assess the efficacy of antibodies used to identify neurogenesis in both neurogenic niches of the human brain.

Methods

Cell proliferation and neurogenesis were simultaneously examined in the SVZ and SGZ of 23 individuals aged 0.2–59 years, using immunohistochemistry and immunofluorescence in combination with unbiased stereology.

Results

There was a marked decline in proliferating cells in both neurogenic niches in early infancy with levels reaching those seen in the adjacent parenchyma by 4 and 1 year of age, in the SVZ and SGZ, respectively. Furthermore, the phenotype of these proliferating cells in both niches changed with age. In infants, proliferating cells co‐expressed neural progenitor (epidermal growth factor receptor), immature neuronal (doublecortin and beta III tubulin) and oligodendrocytic (Olig2) markers. However, after 3 years of age, microglia were the only proliferating cells found in either niche or in the adjacent parenchyma.

Conclusions

This study demonstrates a marked decline in neurogenesis in both neurogenic niches in early childhood, and that the sparse proliferating cells in the adult brain are largely microglia.
“Wild type” GIST: Clinicopathological features and clinical practice
Authors: Wada Ryuichi , Arai Hiroki , Kure Shoko , Peng Wei‐Xia , Naito Zenya
Published: July 2016

Gastrointestinal stromal tumor (GIST) is a mesenchymal tumor of the gastrointestinal tract. Mutation of KIT and PDGFRA genes is implicated in the tumorigenesis. Approximately 10% of GISTs do not harbor mutation of these genes, and they are designated as “wild type” GIST. They are classified into succinate dehydrogenase (SDH)‐deficient and non‐SDH‐deficient groups. SDH‐deficient group includes Carney triad and Carney Stratakis syndrome. The patients are young women. Tumors occur in the antrum of the stomach, and tumor cells are epithelioid. Lymph node metastasis is frequent. The non‐SDH‐deficient group includes neurofibromatosis (NF) type 1 and GISTs with mutations of BRAF, KRAS, and PIK3CA and with the ETV6‐NTRK3 fusion gene. GIST in NF occurs in the small intestine, and tumor cells are spindle shaped. GIST with BRAF mutation arises in the small intestine. Attention to the age, gender, family history and other neoplasms may raise the prediction of syndromic disease. Location of the tumor, morphology, and pleomorphism of the tumor cells are further informative. Lymphovascular invasion should be carefully evaluated. The determination of KIT expression is essential for the diagnosis. When wild type GIST is suspected, intensive genetic analysis is required. Further, a careful and long‐time observation is recommended.
Do Government Purchases Affect Unemployment?
Authors: Holden Steinar , Sparrman Victoria
Published: July 2016

We estimate the effect of government purchases on unemployment in 20 OECD countries, for the period 1980–2007. An increase in government purchases, equal to 1 percent of GDP, is found to reduce unemployment by about 0.3 percentage points in the same year. The effect is greater and more persistent under less “employment‐friendly” labour‐market institutions, and it is greater and more persistent under a fixed exchange rate regime than under a floating regime. The effect is also greater in downturns than in booms. The effect on unemployment reflects a corresponding positive effect of increased government purchases on the employment‐to‐population rate.
Age‐related differences in morphological characteristics of residual skin surface components collected from the surface of facial skin of healthy male volunteers
Authors: Chalyk N. E. , Bandaletova T. Y. , Kyle N. H. , Petyaev I. M.
Published: July 2016

Background/Purpose

Global increase of human longevity results in the emergence of previously ignored ageing‐related problems. Skin ageing is a well‐known phenomenon, but active search for scientific approaches to its prevention and even skin rejuvenation is a relatively new area. Although the structure and composition of the stratum corneum (SC), the superficial layer of epidermis, is well studied, relatively little is known about the residual skin surface components (RSSC) that overlay the surface of the SC. The aim of this study was to examine morphological features of RSSC samples non‐invasively collected from the surface of human facial skin for the presence of age‐related changes.

Methods

Residual skin surface component samples were collected by swabbing from the surface of facial skin of 60 adult male volunteers allocated in two age groups: 34 subjects aged in the range 18–32 years and 26 subjects aged in the range 58–72 years. The collected samples were analysed microscopically: the size of the lipid droplets was measured; desquamated corneocytes and lipid crystals were counted; and microbial presence was assessed semi‐quantitatively.

Results

Age‐related changes were revealed for all studied components of the RSSC. There was a significant (P = 0.0126) decrease in the size of lipid droplets among older men. Likewise, significantly (P = 0.0252) lower numbers of lipid crystals were present in this group. In contrast, microbial presence in the RSSC was significantly (P = 0.0019) increased in the older group. There was also a trend towards more abundant corneocyte desquamation among older men, but the difference has not reached statistical significance (P = 0.0636).

Conclusion

Non‐invasively collected RSSC samples present an informative material for studying age‐related changes on the surface of the SC of human facial skin. The results of this study confirm earlier observations regarding age‐associated decline of the efficiency of the epidermal barrier and can be used for testing new approaches to skin ageing prevention.
How to probe expletives
Authors: Abe Jun
Published: July 2016

This article argues for a Move‐approach to expletive constructions, according to which expletives satisfy theEPPby moving to a designated position rather than by being simply externally merged into it. In particular, I argue that the expletive and its associate form a constituent underlyingly and that the associate carries partitive Case that needs to be checked in accordance with Chomsky's (2008) probe‐goal system. Further, I propose that expletives carry only unvalued ϕ‐features, unlike ordinaryDPs. This makes it possible to accommodate those cases in which expletives appear to be involved in default agreement.
Paraganglioma, pituitary adenoma, and osteosarcoma in a dog
Authors: Robat Cecilia , Houseright Ruth , Murphey Joanne , Sample Saundra , Pinkerton Marie
Published: July 2016

An 11‐year‐old neutered male Alaskan Malamute mixed‐breed dog was presented with a complaint of polyuria/polydipsia (PU/PD), weight loss, tachypnea, regurgitation, and a previous history of nontreated osteosarcoma of the right distal radius, diagnosed 21 months prior. On physical examination, an abdominal mass was palpated. The abdominal mass was aspirated and cytologically diagnosed as a neuroendocrine tumor, suspected to be a pheochromocytoma. Laboratory examination revealed a mild anemia and thrombocytopenia, markedly elevatedATPandALPactivities, and moderate hypercalcemia. A low‐dose dexamethasone suppression test and endogenous adrenocorticotropic hormone (ACTH) concentration were compatible with pituitary hyperadrenocorticism. On urinalysis, proteinuria was noted as well as a high urine metanephrine/creatinine ratio, consistent with a diagnosis of pheochromocytoma. The dog was treated with supportive care and euthanized 6 months later due to decreasing quality of life. On necropsy, an extra‐adrenal pheochromocytoma (paraganglioma) was diagnosed in the caudal abdomen, and a pituitary adenoma and an osteosarcoma of the right distal radius were confirmed.
Quality requirements for veterinary hematology analyzers in small animals—a survey about veterinary experts′ requirements and objective evaluation of analyzer performance based on a meta‐analysis of method validation studies: bench top hematology analyzer
Authors: Cook Andrea M. , Moritz Andreas , Freeman Kathleen P. , Bauer Natali
Published: July 2016

Background

Scarce information exists about quality requirements and objective evaluation of performance of large veterinary bench top hematology analyzers.

Objective

The study was aimed at comparing the observed total error (TEobs) derived from meta‐analysis of published method validation data to the total allowable error (TEa) for veterinary hematology variables in small animals based on experts′ opinions. Ideally, TEobs should be < TEa.

Methods

An online survey was sent to veterinary experts in clinical pathology and small animal internal medicine for providing the maximal allowable deviation from a given result for each variable. Percent of TEa = (allowable median deviation/clinical threshold) * 100%. Second, TEobs for 3 laser‐based bench top hematology analyzers (ADVIA 2120; Sysmex XT2000iV, and CellDyn 3500) was calculated based on method validation studies published between 2005 and 2013 (n = 4). The percent TEobs = 2 * CV (%) + bias (%). The CV was derived from published studies except for the ADVIA 2120 (internal data), and bias was estimated from the regression equation.

Results

A total of 41 veterinary experts (19 diplomates, 8 residents, 10 postgraduate students, 4 anonymous specialists) responded. The proposed range of TEa was wide, but generally ≤ 20%. The TEobs was < TEa for all variables and analyzers except for canine and feline HGB (high bias, low CV) and platelet counts (high bias, high CV).

Conclusions

Overall, veterinary bench top analyzers fulfilled experts′ requirements except for HGB due to method‐related bias, and platelet counts due to known preanalytic/analytic issues.
Genetic testing in veterinary dermatology
Authors: Leeb Tosso , Müller Eliane J. , Roosje Petra , Welle Monika
Published: July 2016

Background

Molecular genetics has made significant advances in the analysis of hereditary dermatoses during the last several years.

Objectives

To provide an update on currently available genetic tests for skin diseases of dogs, cats and horses, and to aid the veterinary clinician in the appropriate selection and applications of genetic tests.

Methods

The scientific literature on the topic was critically reviewed. The list of known causative variants for genodermatoses and hair morphology traits was compiled by searching the Online Mendelian Inheritance in Animals (OMIA) database.

Results

Genetic testing has become an important diagnostic method in veterinary medicine. Genetic tests can help to establish the correct diagnosis in some diseases with relatively nonspecific signs. Genetic tests are also essential for sustainable breeding programmes and to help minimize the frequency of animals with hereditary diseases. Advances in genetic methodology and bioinformatics already allow genome‐wide screening for potential disease causing mutations for research purposes. It is anticipated that this will become a routine process in clinical practice in the future.

Conclusion and clinical importance

As specific DNA tests and broad genome‐wide analyses come into more common use, it is critical that clinicians understand the proper application and interpretation of these test results.
The selective glucocorticoid receptor agonist mapracorat displays a favourable safety–efficacy ratio for the topical treatment of inflammatory skin diseases in dogs
Authors: Bäumer Wolfgang , Rossbach Kristine , Schmidt Bernard H.
Published: July 2016

Background

Mapracorat is a nonsteroidal Selective Glucocorticoid Receptor Agonist (SEGRA) that is presumed to have a better therapeutic index compared to classical glucocorticoids.

Objectives

To compare the efficacy and safety of mapracorat with classical glucocorticoids used for the treatment of allergic skin diseases in dogs.

Animals

Six laboratory beagles.

Methods

The effect of mapracorat on lipopolysaccharide‐induced TNFα secretion from canine peripheral blood derived mononuclear cells (PBMC) was tested. In vivo, mapracorat was compared to triamcinolone acetonide using a skin inflammation model. Skin fold thickness was determined after daily administration of mapracorat and triamcinolone acetonide over 14 days.

Results

Mapracorat concentration dependently inhibited TNFα secretion from activated canine PBMC with a half maximal inhibitory concentration (IC50) value of approximately 0.2 nmol/L. Intradermal injection of compound 48/80 (50 μg in 50 μL saline) resulted in a clear wheal and flare reaction over the 60 min observation period. Topical pre‐treatment with mapracorat (0.1%) and triamcinolone acetonide (0.015%) led to significant reduction in the wheal and flare responses compared to vehicle (acetone) treated areas. However, once daily topical administration of triamcinolone acetonide significantly reduced skin fold thickness from day 8 to 14, whereas no such reduction was observed for mapracorat.

Conclusion

These results demonstrate that mapracorat has comparable anti‐inflammatory efficacy to classical steroidal glucocorticoids under these experimental settings and maintenance of skin fold thickness indicates a better safety profile compared to triamcinolone acetonide at equipotent concentrations. This profile further suggests that SEGRAs show promise in the management of inflammatory and pruritic skin diseases in dogs.
Angiotensin II control of regional haemodynamics in rats with aortocaval fistula
Authors: Duggan Daniel J. , Tabrizchi Reza
Published: July 2016

New Findings

What is the central question of this study?

Hyperdynamic circulation because of arteriovenous fistula results in reduction of blood flow to organs but is a model of low circulatory resistance with activated renin–angiotensin system. The aim was to determine contributions of different subtypes of angiotensin II receptors to regional blood flow and vascular conductance in a hyperdynamic circulatory state.

What is the main finding and its importance?

The renin–angiotensin system plays a pivotal role in control of regional blood flow in animals with arteriovenous fistula and makes a major contribution to the maintenance of normal arterial blood pressure. In this hyperdynamic circulatory state model, angiotensin II type 1 receptors predominated in regulating regional haemodynamics.

Regional perfusion is reduced and the renin–angiotensin system activated in rats with aortocaval fistula. The effects of captopril (angiotensin‐converting enzyme inhibitor), losartan (angiotensin II type 1 receptor antagonist) and PD 123319 (angiotensin II type 2 receptor antagonist) on regional blood flow and vascular conductance were assessed in rats with aortocaval fistula and sham‐operated rats. Control of blood flow and vascular conductance by angiotensin II was evaluated by serial bolus injections of captopril, losartan and PD 123319 in anaesthetized rats. In rats with fistula, PD 123319 significantly decreased, whereas captopril and losartan increased, mesenteric blood flow. The decrease in mesenteric blood flow induced by PD 123319 was significantly greater in rats with fistula compared with sham operation. Captopril and PD 123319 significantly decreased renal blood flow compared with losartan, which increased it. In sham‐operated rats, captopril and losartan significantly increased, whereas PD 123319 decreased, mesenteric and renal conductance. In rats with fistula, captopril and losartan significantly increased, whereas PD 123319 decreased, mesenteric conductance. The significant increase produced by losartan on mesenteric conductance was greater in rats with fistula compared with sham operation. PD 123319 produced a significantly greater decrease in renal conductance of rats with aortocaval fistula compared with sham‐operated rats. Captopril, losartan and PD 123319 did not significantly affect perfusion in the hindquarter in rats with fistula or sham‐operated. The renin–angiotensin system is more active in the control of regional haemodynamics in rats with aortocaval fistula and acts as a mechanism of maintaining normal arterial blood pressure in these animals. In rats with fistula, angiotensin II type 1 receptors predominate in regulating regional haemodynamics.
From focal sepsis to periodontal medicine: a century of exploring the role of the oral microbiome in systemic disease
Authors: Kumar Purnima S.
Published: July 2016

The oral microbiome is established within a few minutes after birth and consists of stable multi‐species communities that engage in a dynamic equilibrium with the host immune system. Dental caries, endodontic infections and periodontal diseases are bacterially driven diseases that are caused by dysbiotic microbiomes. Over a century ago, the focal infection theory implicated these infections in the aetiology of several systemic diseases, ranging from arthritis to neurodegenerative diseases. However, a lack of concrete evidence, combined with the urgency with which clinicians embraced this approach without regard for appropriate case selection, led to its demise within 30 years. In the last decade of the 20th century, the concept of periodontal medicine was introduced to explain the correlations that were being observed between periodontitis and cardiovascular disease, rheumatoid arthritis, Alzheimer's disease, pulmonary disease, pre‐term delivery of low birth weight infants and metabolic disease. It was proposed that periodontal pathobionts played a causal role in the initiating or exacerbating certain diseases either by direct invasion or by stimulating a florid immune‐inflammatory response that extended into the systemic circulation. This review will examine the strength of current evidence in establishing a causal link between oral pathobionts and systemic disease.

image
In vivo matching of postsynaptic excitability with spontaneous synaptic inputs during formation of the rat calyx of Held synapse
Authors: Sierksma Martijn C. , Tedja Milly S. , Borst J. Gerard G.
Published: July 2016

Key points

Neurons in the medial nucleus of the trapezoid body of anaesthetized rats of postnatal day (P)2–6 showed burst firing with a preferred interval of about 100 ms, which was stable, and a second preferred interval of 5–30 ms, which shortened during development.

In 3 out of 132 cases, evidence for the presence of two large inputs was found.

In vivo whole‐cell recordings revealed that the excitability of the principal neuron and the size of its largest synaptic inputs were developmentally matched.

At P2–4, action potentials were triggered by barrages of small synaptic events that summated to plateau potentials, while at later stages firing depended on a single, large and often prespike‐associated input, which is probably the nascent calyx of Held.

Simulations with a Hodgkin–Huxley‐like model, which was based on fits of the intrinsic postsynaptic properties, suggested an essential role for the low‐threshold potassium conductance in this transition.

In the adult, principal neurons of the medial nucleus of the trapezoid body (MNTB) are typically contacted by a single, giant terminal called the calyx of Held, whereas during early development a principal neuron receives inputs from many axons. How these changes in innervation impact the postsynaptic activity has not yet been studied in vivo. We therefore recorded spontaneous inputs and intrinsic properties of principal neurons in anaesthetized rat pups during the developmental period in which the calyx forms. A characteristic bursting pattern could already be observed at postnatal day (P)2, before formation of the calyx. At this age, action potentials (APs) were triggered by barrages of summating EPSPs causing plateau depolarizations. In contrast, at P5, a single EPSP reliably triggered APs, resulting in a close match between pre‐ and postsynaptic firing. Postsynaptic excitability and the size of the largest synaptic events were developmentally matched. The developmental changes in intrinsic properties were estimated by fitting in vivo current injections to a Hodgkin–Huxley‐type model of the principal neuron. Our simulations indicated that the developmental increases in Ih, low‐threshold K+ channels and leak currents contributed to the reduction in postsynaptic excitability, but that low‐threshold K+ channels specifically functioned as a dampening influence in the near‐threshold range, thus precluding small inputs from triggering APs. Together, these coincident changes help to propagate bursting activity along the auditory brainstem, and are essential steps towards establishing the relay function of the calyx of Held synapse.
The Effects of the Inertial Properties of Above-Knee Prostheses on Optimal Stiffness, Damping, and Engagement Parameters of Passive Prosthetic Knees
Authors: Narang Yashraj S. , Murthy Arelekatti V. N. , Winter Amos G.
Published: July 2016

Our research aims to design low-cost, high-performance, passive prosthetic knees for developing countries. In this study, we determine optimal stiffness, damping, and engagement parameters for a low-cost, passive prosthetic knee that consists of simple mechanical elements and may enable users to walk with the normative kinematics of able-bodied humans. Knee joint power was analyzed to divide gait into energy-based phases and select mechanical components for each phase. The behavior of each component was described with a polynomial function, and the coefficients and polynomial order of each function were optimized to reproduce the knee moments required for normative kinematics of able-bodied humans. Sensitivity of coefficients to prosthesis mass was also investigated. The knee moments required for prosthesis users to walk with able-bodied normative kinematics were accurately reproduced with a mechanical system consisting of a linear spring, two constant-friction dampers, and three clutches (R2=0.90 for a typical prosthetic leg). Alterations in upper leg, lower leg, and foot mass had a large influence on optimal coefficients, changing damping coefficients by up to 180%. Critical results are reported through parametric illustrations that can be used by designers of prostheses to select optimal components for a prosthetic knee based on the inertial properties of the amputee and his or her prosthetic leg.
The Transverse Isotropy of Spinal Cord White Matter Under Dynamic Load
Authors: Jannesar Shervin , Nadler Ben , Sparrey Carolyn J.
Published: July 2016

The rostral-caudally aligned fiber-reinforced structure of spinal cord white matter (WM) gives rise to transverse isotropy in the material. Stress and strain patterns generated in the spinal cord parenchyma following spinal cord injury (SCI) are multidirectional and dependent on the mechanism of the injury. Our objective was to develop a WM constitutive model that captures the material transverse isotropy under dynamic loading. The WM mechanical behavior was extracted from the published tensile and compressive experiments. Combinations of isotropic and fiber-reinforcing models were examined in a conditional quasi-linear viscoelastic (QLV) formulation to capture the WM mechanical behavior. The effect of WM transverse isotropy on SCI model outcomes was evaluated by simulating a nonhuman primate (NHP) contusion injury experiment. A second-order reduced polynomial hyperelastic energy potential conditionally combined with a quadratic reinforcing function in a four-term Prony series QLV model best captured the WM mechanical behavior (0.89 < R2 < 0.99). WM isotropic and transversely isotropic material models combined with discrete modeling of the pia mater resulted in peak impact forces that matched the experimental outcomes. The transversely isotropic WM with discrete pia mater resulted in maximum principal strain (MPS) distributions which effectively captured the combination of ipsilateral peripheral WM sparing, ipsilateral injury and contralateral sparing, and the rostral/caudal spread of damage observed in in vivo injuries. The results suggest that the WM transverse isotropy could have an important role in correlating tissue damage with mechanical measures and explaining the directional sensitivity of the spinal cord to injury.
Quantitative Computed Tomography Protocols Affect Material Mapping and Quantitative Computed Tomography-Based Finite-Element Analysis Predicted Stiffness
Authors: Giambini Hugo , Dragomir-Daescu Dan , Nassr Ahmad , Yaszemski Michael J. , Zhao Chunfeng
Published: July 2016

Quantitative computed tomography-based finite-element analysis (QCT/FEA) has become increasingly popular in an attempt to understand and possibly reduce vertebral fracture risk. It is known that scanning acquisition settings affect Hounsfield units (HU) of the CT voxels. Material properties assignments in QCT/FEA, relating HU to Young's modulus, are performed by applying empirical equations. The purpose of this study was to evaluate the effect of QCT scanning protocols on predicted stiffness values from finite-element models. One fresh frozen cadaveric torso and a QCT calibration phantom were scanned six times varying voltage and current and reconstructed to obtain a total of 12 sets of images. Five vertebrae from the torso were experimentally tested to obtain stiffness values. QCT/FEA models of the five vertebrae were developed for the 12 image data resulting in a total of 60 models. Predicted stiffness was compared to the experimental values. The highest percent difference in stiffness was approximately 480% (80 kVp, 110 mAs, U70), while the lowest outcome was ∼1% (80 kVp, 110 mAs, U30). There was a clear distinction between reconstruction kernels in predicted outcomes, whereas voltage did not present a clear influence on results. The potential of QCT/FEA as an improvement to conventional fracture risk prediction tools is well established. However, it is important to establish research protocols that can lead to results that can be translated to the clinical setting.
An Efficient Unsteady Adjoint Optimization System for Multistage Turbomachinery
Authors: Ma Can , Su Xinrong , Yuan Xin
Published: July 2016

Unsteady blade row interactions play an important role in the performance of multistage turbomachinery. However, most aerodynamic optimizations of multistage turbomachinery are based on mixing-plane steady flow simulations. To take into account the unsteady flow features in the optimization cycle, this paper develops an adjoint-based unsteady aerodynamic optimization system for multistage turbomachinery. To the authors' best knowledge, this is the first work in the literature conducting the unsteady adjoint aerodynamic optimization of multistage turbomachinery. The unsteady flow equations and the discrete adjoint equations are solved using a finite volume code, with the harmonic balance method adopted to reduce the cost of unsteady simulations. The system is applied to the unsteady aerodynamic optimization of a 1.5-stage compressor. Results show the efficiency and capability of the proposed framework for the unsteady aerodynamic optimization of multistage turbomachinery.
Modeling of Hydrophobic Surfaces by the Stokes Problem With the Stick–Slip Boundary Conditions
Authors: Kučera R. , Šátek V. , Haslinger J. , Fialová S. , Pochylý F.
Published: July 2016

Unlike the Navier boundary condition, this paper deals with the case when the slip of a fluid along the wall may occur only when the shear stress attains certain bound which is given a priori and does not depend on the solution itself. The mathematical model of the velocity–pressure formulation with this type of threshold slip boundary condition is given by the so-called variational inequality of the second kind. For its discretization, we use P1-bubble/P1 mixed finite elements. The resulting algebraic problem leads to the minimization of a nondifferentiable energy function subject to linear equality constraints representing the discrete impermeability and incompressibility condition. To release the former one and to regularize the nonsmooth term characterizing the stick–slip behavior of the algebraic formulation, two additional vectors of Lagrange multipliers are introduced. Further, the velocity vector is eliminated, and the resulting minimization problem for a quadratic function depending on the dual variables (the discrete pressure and the normal and shear stress) is solved by the interior point type method which is briefly described. To justify the threshold model and to illustrate the efficiency of the proposed approach, three physically realistic problems are solved and the results are compared with the ones solving the Stokes problem with the Navier boundary condition.
Bi induced superstructures on Si(110)
Authors: Ang Artoni Kevin R. , Takeda Sakura Nishino , Daimon Hiroshi
Published: July 2016

The authors report new surface reconstructions that are produced when Bi is adsorbed on Si(110) surfaces held at high substrate temperatures. At 600 °C and a Bi coverage of 0.1 ML, reflection high energy electron diffraction (RHEED) patterns reveal the formation of a 3×″4″-Bi structure with b1 = 3a1 and b2=−a1+4a2. At 630 °C and 0.2 ML Bi coverage, a 3×″6″-Bi structure is observed, with b1=3a1 and b2=−a1+6a2. The coexistence of streaks and spots in the RHEED patterns of the 3×″4″ and 3×″6″ structures indicate a high density of antiphase domains, with poor structural correlation along the [001] direction. The authors propose structural models based on rows of Bi adatoms aligned along the [1¯10] direction. The models proposed can also be applied to similar reconstructions on Si(110) adsorbed with other metals.
Vowel reduction across tasks for male speakers of American English
Authors: Kuo Christina , Weismer Gary
Published: July 2016

This study examined acoustic variation of vowels within speakers across speech tasks. The overarching goal of the study was to understand within-speaker variation as one index of the range of normal speech motor behavior for American English vowels. Ten male speakers of American English performed four speech tasks including citation form sentence reading with a clear-speech style (clear-speech), citation form sentence reading (citation), passage reading (reading), and conversational speech (conversation). Eight monophthong vowels in a variety of consonant contexts were studied. Clear-speech was operationally defined as the reference point for describing variation. Acoustic measures associated with the conventions of vowel targets were obtained and examined. These included temporal midpoint formant frequencies for the first three formants (F1, F2, and F3) and the derived Euclidean distances in the F1–F2 and F2–F3 planes. Results indicated that reduction toward the center of the F1–F2 and F2–F3 planes increased in magnitude across the tasks in the order of clear-speech, citation, reading, and conversation. The cross-task variation was comparable for all speakers despite fine-grained individual differences. The characteristics of systematic within-speaker acoustic variation across tasks have potential implications for the understanding of the mechanisms of speech motor control and motor speech disorders.
Low frequency sound spatial encoding within an enclosure using spherical microphone arrays
Authors: Wang Yan , Chen Kean
Published: July 2016

In a spherical coordinate system, interior sound field can be expressed in terms of a series of Fourier-Bessel expansions. The process that obtains the expansion coefficients by use of a microphone array (e.g., a spherical microphone array) is called spatial encoding. Until now spatial encoding has mainly been examined in a free field or a diffuse field which can be modeled as a sum of plane waves. For spatial encoding within an enclosure at low frequencies, special challenges would be encountered in two aspects. First, the expansions are influenced by array configurations. Second, an acoustic mode based model instead of a plane wave based one should be considered. This study focuses on these challenges. Different kinds of array configurations were compared specifically at low frequencies, and the spatial encoding for the cylindrical cavity modes was investigated. It was found that the spherical array with cardioid microphones was optimal when kr<1, the cavity modes can be effectively represented by only a sparse subset of expansion coefficients and a good reproduction can be achieved even outside the spherical valid region, which demonstrates an effective alternative way to describe the cylindrical cavity modes and can be implemented efficiently in practice.
The Electromyographic Threshold in Girls and Women
Authors: Long Devon , Dotan Raffy , Pitt Brynlynn , McKinlay Brandon , O’Brien Thomas D. , Tokuno Craig , Falk Bareket
Published: July 2016

Background:

The electromyographic threshold (EMGTh) is thought to reflect increased high-threshold/type-II motor-unit (MU) recruitment and was shown higher in boys than in men. Women differ from men in muscular function.

Purpose:

Establish whether females’ EMGTh and girls–women differences are different than males’.

Methods:

Nineteen women (22.9 ± 3.3yrs) and 20 girls (10.3 ± 1.1yrs) had surface EMG recorded from the right and left vastus lateralis muscles during ramped cycle-ergometry to exhaustion. EMG root-mean-squares were averaged per pedal revolution. EMGTh was determined as the least residual sum of squares for any two regression-line data divisions, if the trace rose ≥ 3SD above its regression line. EMGTh was expressed as % final power-output (%Pmax) and %VO2pk power (%PVO2pk).

Results:

EMGTh was detected in 13 (68%) of women, but only 9 (45%) of girls (p < .005) and tended to be higher in the girls (%Pmax= 88.6 ± 7.0 vs. 83.0 ± 6.9%, p = .080; %PVO2pk= (101.6 ± 17.6 vs. 90.6 ± 7.8%, p = .063). When EMGTh was undetected it was assumed to occur at 100%Pmax or beyond. Consequently, EMGTh values turned significantly higher in girls than in women (94.8 ± 7.4 vs. 88.4 ± 9.9%Pmax, p = .026; and 103.2 ± 11.7 vs. 95.2 ± 9.9%PVO2pk, p = .028).

Conclusions:

During progressive exercise, girls appear to rely less on higher-threshold/type-II MUs than do women, suggesting differential muscle activation strategy.
Number of Daily Steps to Discriminate Abdominal Obesity in a Sample of Brazilian Children and Adolescents
Authors: Gordia Alex Pinheiro , de Quadros Teresa Maria Bianchini , Mota Jorge , Silva Luciana Rodrigues
Published: July 2016

Purpose:

Weight status-referenced pedometer step-count guidelines for young people have been developed for populations from high-income countries and may not be applicable to middle- and low-income countries. The objectives of this study were 1) to develop cut-off points for pedometer-determined step count in young Brazilians using waist circumference (WC) as a reference criterion, and 2) to analyze the capacity of previous recommendations to discriminate abdominal obesity in the sample studied.

Methods:

A cross-sectional study was conducted on 1,044 schoolchildren (456 boys) aged 6–17 years from Northeastern Brazil. WC was measured and daily step counts were determined with a pedometer.

Results:

The area under the curve (AUC) of step count was significant for boys (AUC = 0.55; 95%CI: 0.50–0.59) and girls (AUC = 0.57; 95%CI: 0.53–0.61). Our cut-off points (14,414 and 11,355 steps for boys and girls, respectively) were more balanced in terms of sensitivity and specificity compared with previous recommendations. The use of previous guidelines to classify step count in the sample provided very low sensitivity or specificity and wide variation in the prevalence of insufficient physical activity (39.3–77.0%).

Conclusions:

A universal step-count recommendation for young people may not be adequate and specific guidelines seem to be necessary for different countries or regions.
Interpretation of molecular device transport calculations
Authors: Gibbs Josh , Otero de la Roza Alberto , Bergren Adam Johan , DiLabio Gino A.
Published: July 2016

The field of molecular electronics will benefit from rational design approaches based on a complete understanding of the electronic structure of molecule-based devices. However, many computational approaches that are used to study molecular-scale devices are based on methods that have deficiencies that must be understood in order for those methods to be useful to the modeling and experimental community. Density-functional theory based methods have some well-known pitfalls that limit their application to the study of electron transport in models of molecular junction devices. Some of the impacts of these deficiencies are highlighted in this work through the use of a graphene model system and a variety of simple hydrocarbon molecules. Self-interaction error in simple functionals built from the local density approximation and the generalized gradient approximation results in very large errors in predicted absolute and relative ionization potentials. This demonstrates that electron transmission spectra predicted using these functionals should be considered with caution. We also demonstrate that care must be taken with the use of finite models for electrodes.
A relation between diffusion, temperature and the cosmological constant
Authors: Haba Z.
Published: July 2016

We show that the temperature of a diffusing fluid with the diffusion constant [Formula: see text] in an expanding universe approaches a constant limit [Formula: see text] in its final de Sitter stage characterized by the horizon [Formula: see text] determined by the Hubble constant. If de Sitter surface temperature in the final equilibrium state coincides with the fluid temperature, then the cosmological constant [Formula: see text].
Site occupation, phase stability, crystal and electronic structures of the doped S phase (Al2CuMg)
Authors: Gu Jianglong , Gu Huimin , Zhai Yuchun , Ma Peihua
Published: July 2016

The S phase (Al2CuMg) is an important strengthening phase for the Al–Cu–Mg alloys, which are widely used in the aerospace and transportation industries. The commonly added alloying elements (Mn, Ti, Zr) and the impurity elements (Fe and Si) in the Al–Cu–Mg alloys are always found in the S phase. First-principles calculations based on the density functional theory (DFT) were used to investigate the influence of doping Mn, Ti, Zr, Fe and Si elements on the S phase. Key findings demonstrated that these elements prefer to occupy different atomic sites in the S phase. Ti and Zr improved the structural stability of the S phase. The bulk modulus of the Fe, Si, Ti and Zr doped S phases becomes larger than that of the pure S phase. Both the crystal and electronic structures of the S phase are affected by the dopants. The results of this study provide a better theoretical understanding of the S phase, providing guidance for improved composition design and performance optimization of Al–Cu–Mg alloys.
Monte Carlo simulation of the influence of pressure and target–substrate distance on the sputtering process for metal and semiconductor layers
Authors: Bouazza Abdelkader , Settaouti Abderrahmane
Published: July 2016

The energy and the number of particles arriving at the substrate during physical vapor deposition (PVD) are in close relation with divers parameters. In this work, we present the influence of the distance between the target and substrate and the gas pressure in the sputtering process of deposited layers of metals (Cu, Al and Ag) and semiconductors (Ge, Te and Si) for substrate diameter of 40 cm and target diameter of 5 cm. The nascent sputter flux, the flux of the atoms and their energy arriving at the substrate have been simulated by Monte Carlo codes. A good agreement between previous works of other groups and our simulations for sputter pressures (0.3–1 Pa) and target–substrate distances (8–20 cm) is obtained.
Design of layered structure for thermal cloak with complex shape
Authors: Yuan Xuebo , Lin Guochang , Wang Youshan
Published: July 2016

Thermal cloaks have potential applications in thermal protection and sensing, and those cloaks with complex shapes are much more efficient in application. Layered discretization is a valid way to realize thermal cloaks designed through spatial transformation which are usually nonhomogeneous and anisotropic. However, previous studies are limited to two-dimensional cylindrical ones. Based on the theories of spatial transformation and effective medium, a four-step design method for layered structure of thermal cloak with complex shape is proposed. It is expected to realize the designed layered structure by utilizing the existing regular materials. According to the numerical simulations, the thermal cloaking performances of layered structures are good and close to that of the perfect thermal cloaks. This study has provided an effective way for realizing thermal cloak with complex shape.
OPTIMAL HARVESTING OF FISHING AQUACULTURE IN THE ENVIRONMENT WITH PRYMNESIACEE TOXIN
Authors: ZHANG SHUANGHONG , ZHANG QINGLING , LIU CHAO
Published: July 2016

In this paper, the issue on the optimal harvesting of fish catching after eliminating toxin during the fish aquaculture is studied. Taking the aquaculture of bighead carp and silver carp as an example, considering the characteristics of the growth and the reproduction of prymnesiacee, and taking prymnesiacee toxin as the pollutant source, a harvesting model of fish aquaculture is built. The finite-time stability of the system is discussed. While the fish aquaculture and the elimination of the algae toxin targeted as pollutant source can be carried out simultaneously, an optimal harvesting method is made by the Pontryagin maximum principle, from which a general algorithm of the optimal harvesting solution can be obtained. The stimulation shows the effectiveness of the result.
CONSTRUCTION OF AESTHETIC SPHERICAL PATTERNS FROM PLANAR IFSs
Authors: CHEN NING , ZHANG YUTING , CHUNG K. W.
Published: July 2016

To construct symmetrical patterns on the unit sphere from the planar iterative function systems (IFSs), we present a method of constructing IFSs with [Formula: see text] symmetry which is composed of three-fold rotational symmetries together with reflections. An algorithm is developed to generate strange attractors with [Formula: see text] symmetry on a triangular face and then project it onto the surface of the unit sphere to form aesthetics patterns with spherical symmetry. As an illustrative example, we consider the regular inscribed icosahedron in the unit sphere which contains 20 triangular faces. This method is valid to randomly generate aesthetic spherical patterns using planar IFSs.