bluuebunny/crossref_metadata_2025 huggingface dataset:
Making a meaningful impact: modelling simultaneous frictional collisions in spatial multibody systems
Authors: Uchida Thomas K. , Sherman Michael A. , Delp Scott L.
Published: April 2015

Impacts are instantaneous, computationally efficient approximations of collisions. Current impact models sacrifice important physical principles to achieve that efficiency, yielding qualitative and quantitative errors when applied to simultaneous impacts in spatial multibody systems. We present a new impact model that produces behaviour similar to that of a detailed compliant contact model, while retaining the efficiency of an instantaneous method. In our model, time and configuration are fixed, but the impact is resolved into distinct compression and expansion phases, themselves comprising sliding and rolling intervals. A constrained optimization problem is solved for each interval to compute incremental impulses while respecting physical laws and principles of contact mechanics. We present the mathematical model, algorithms for its practical implementation, and examples that demonstrate its effectiveness. In collisions involving materials of various stiffnesses, our model can be more than 20 times faster than integrating through the collision using a compliant contact model. This work extends the use of instantaneous impact models to scientific and engineering applications with strict accuracy requirements, where compliant contact models would otherwise be required. An open-source implementation is available in Simbody, a C++ multibody dynamics library widely used in biomechanical and robotic applications.
Characterization of the microaerophilic, bacteriochlorophyll a-containing bacterium Gemmatimonas phototrophica sp. nov., and emended descriptions of the genus Gemmatimonas and Gemmatimonas aurantiaca
Authors: Zeng Yonghui , Selyanin Vadim , Lukeš Martin , Dean Jason , Kaftan David , Feng Fuying , Koblížek Michal
Published: April 2015

A red-pigmented, bacteriochlorophyll (BChl)a-producing strain, AP64T, was isolated previously from the freshwater Swan Lake located in the western Gobi Desert. Based on its 16S rRNA gene sequence identity (96.1 %) to the type strainGemmatimonas aurantiacaT-27T, the new isolate was tentatively classified as a member of the bacterial phylumGemmatimonadetes. Here, we report its formal description and polyphasic characterization. Strain AP64Tgrew best on agar media under 9.8–15.2 % atmospheric oxygen. The cells were rods, dividing by symmetrical or asymmetrical binary fission. Budding structures were also observed. Its genomic DNA G+C content was 64.4 % (from the draft genome sequence). Phylogenetic analysis based on the 16S rRNA gene sequence clearly separated AP64Tfrom related species. Its genotypic differentiation from phylogenetically close relatives was further supported by performingin silicoDNA–DNA hybridization and calculating average nucleotide identity, whereas the high percentage (67.3 %) of shared conserved proteins between strain AP64TandGemmatimonas aurantiacaT-27Tsupports the classification of the two strains into the same genus. Strain AP64Tcontained C16 : 1, C14 : 1and C18 : 1ω9cas predominant fatty acids. The main respiratory quinone was menaquinone 8 (MK-8). The most distinctive feature of strain AP64Twas the presence of fully functional purple bacterial photosynthetic reaction centres. The main CO2-fixation pathways were absent. Strain AP64Twas capable of growth and BChl production in constant darkness. Thus, strain AP64Tis a facultatively photoheterotrophic organism. It represents a novel species of the genusGemmatimonas, for which the nameGemmatimonasphototrophicasp. nov. is proposed. The type strain is AP64T( = DSM 29774T = MCCC 1K00454T). Emended descriptions of the genusGemmatimonasandGemmatimonas aurantiacaare also provided.
Halovarius luteus gen. nov., sp. nov., an extremely halophilic archaeon from a salt lake
Authors: Mehrshad Maliheh , Amoozegar Mohammad Ali , Makhdoumi Ali , Rasooli Mehrnoosh , Asadi Basaer , Schumann Peter , Ventosa Antonio
Published: April 2015

An extremely halophilic archaeon, strain DA50T, was isolated from a brine sample of Urmia lake, a hypersaline environment in north-west Iran. Strain DA50T was orange-pigmented, motile, pleomorphic and required at least 2.5 M NaCl but not MgCl2 for growth. Optimal growth was achieved at 4.0 M NaCl and 0.3 M MgCl2. The optimum pH and temperature for growth were pH 7.0 and 45 °C, while it was able to grow over a pH range of 6.5–8.0 and a temperature range of 25–50 °C. Analysis of 16S rRNA gene sequences revealed that strain DA50T is a member of the family Halobacteriaceae, showing a low level of similarity with other members of this family. Highest similarities, 94.4, 94.0 and 93.9 %, were obtained with the 16S rRNA gene sequences of the type strains of Natrialba aegyptia, Halobiforma lacisalsi and Halovivax asiaticus, respectively. Polar lipid analyses revealed that strain DA50T contains phosphatidylglycerol and phosphatidylglycerol phosphate methyl ester. Four unidentified glycolipids and two minor phospholipids were also observed. The only quinone present was MK-8(II-H2). The G+C content of its DNA was 62.3 mol%. On the basis of the data obtained, the new isolate could not be classified in any recognized genus. Strain DA50T is thus considered to represent a novel species of a new genus within the family Halobacteriaceae, order Halobacteriales, for which the name Halovarius luteus gen. nov., sp. nov. is proposed. The type strain of Halovarius luteus is DA50T ( = IBRC-M 10912T = CECT 8510T).
Latent developmental and evolutionary shapes embedded within the grapevine leaf
Authors: Chitwood Daniel H , Klein Laura L , O'Hanlon Regan , Chacko Steven , Greg Matthew , Kitchen Cassandra , Miller Allison J , Londo Jason P
Published: April 2015

Across plants, leaves exhibit profound diversity in shape. As a single leaf expands, its shape is in constant flux. Plants may also produce leaves with different shapes at successive nodes. Additionally, leaf shape varies among individuals, populations, and species due to evolutionary processes and environmental influences. Because leaf shape can vary in many different ways, theoretically the effects of distinct developmental and evolutionary processes are separable, even within the shape of a single leaf. Here, we measure the shapes of >3,200 leaves representing >270 vines from wild relatives of domesticated grape (Vitis spp.) to determine if leaf shapes attributable to genetics and development are separable from each other. We isolate latent shapes (multivariate signatures that vary independently from each other) embedded within the overall shape of leaves. These latent shapes can predict developmental stages independent from species identity and vice versa. Shapes predictive of development are then used to stage leaves from 1,200 varieties of domesticated grape (Vitis vinifera), revealing that changes in timing underlie leaf shape diversity. Our results indicate distinct latent shapes combine to produce a composite morphology in leaves, and that developmental and evolutionary contributions to shape vary independently from each other.
Dual-energy X-ray analysis using synchrotron computed tomography at 35 and 60 keV for the estimation of photon interaction coefficients describing attenuation and energy absorption
Authors: Midgley Stewart , Schleich Nanette
Published: April 2015

A novel method for dual-energy X-ray analysis (DEXA) is tested using measurements of the X-ray linear attenuation coefficient μ. The key is a mathematical model that describes elemental cross sections using a polynomial in atomic number. The model is combined with the mixture rule to describe μ for materials, using the same polynomial coefficients. Materials are characterized by their electron densityNeand statistical momentsRkdescribing their distribution of elements, analogous to the concept of effective atomic number. In an experiment with materials of known density and composition, measurements of μ are written as a system of linear simultaneous equations, which is solved for the polynomial coefficients. DEXA itself involves computed tomography (CT) scans at two energies to provide a system of non-linear simultaneous equations that are solved forNeand the fourth statistical momentR4. Results are presented for phantoms containing dilute salt solutions and for a biological specimen. The experiment identifies 1% systematic errors in the CT measurements, arising from third-harmonic radiation, and 20–30% noise, which is reduced to 3–5% by pre-processing with the median filter and careful choice of reconstruction parameters. DEXA accuracy is quantified for the phantom as the mean absolute differences forNeandR4: 0.8% and 1.0% for soft tissue and 1.2% and 0.8% for bone-like samples, respectively. The DEXA results for the biological specimen are combined with model coefficients obtained from the tabulations to predict μ and the mass energy absorption coefficient at energies of 10 keV to 20 MeV.
The use of ICT in road freight transport for CO2reduction – an exploratory study of UK’s grocery retail industry
Authors: Wang Yingli , Sanchez Rodrigues Vasco , Evans Leighton
Published: April 2015

Purpose

– The purpose of this paper is to investigate empirically how information and communication technologies (ICT) can contribute to reduction of CO2emissions in road freight transport and to identify opportunities for further improvements.

Design/methodology/approach

– This research adopts a multiple case study approach with three leading UK grocery retailers as exemplars of fast-moving consumer goods retailers, conducted using multiple data collection techniques including interviews, system demonstrations, onsite observations and the use of archive information.

Findings

– ICT solutions have a direct positive impact on CO2emissions reduction but opportunities to further reduce CO2emissions are perceived as lying beyond retailers’ own distribution networks. These opportunities are not fully utilised due to the complexities of collaborative ICT provisions and retailers’ reluctance to share information with competitors.

Research limitations/implications

– A limitation of the study is that it is exploratory and only three cases were examined. Even though these three retailers represent over 60 per cent of the UK grocery retail sector, other retailers may deploy significantly different ICT applications.

Practical implications

– The research provides an overarching insight for businesses on how to leverage the existing and emerging information technologies for environmental and economic benefits.

Originality/value

– While sustainability issues have received increasing attention recently, the role of ICT in freight transport for CO2emissions reduction has not been investigated in depth and its impact is largely unknown. This research advances understanding about how ICT contributes CO2emissions reductions and provides a framework for further investigation.
The impacts of IT capability on internet-enabled supply and demand process integration, and firm performance in manufacturing and services
Authors: Liu Hefu , Huang Qian , Wei Shaobo , Huang Liqiang
Published: April 2015

Purpose

– The purpose of this paper is to derive a model to examine how Information Technology (IT) capability affects internet-enabled supply and demand process integration, which will eventually improve firm performance. In addition, the moderating effects of industry type in the research framework are explored.

Design/methodology/approach

– Data were obtained from a survey administered to 261 firms in the manufacturing and services industry in China. The structural equation modeling approach is used to test the hypotheses. The study further applied thet-test to compare the path coefficiencies between manufacturing and service.

Findings

– Results from the survey indicate that internet-enabled supply and demand process integration is affected by IT capability, and can directly impact firm performance. The results further indicate that manufacturing and services firms may benefit from IT capability in different ways.

Originality/value

– The current paper contributes knowledge on the value-realizing mechanism of internet-enabled supply chain integration (SCI) from a resource-based view. It presents a multidimensional explanation of the relationships among IT capability, internet-enabled SCI, and firm performance.
Build strategies for rapid manufacturing of components of varying complexity
Authors: Simhambhatla Suryakumar , Karunakaran K.P.
Published: April 2015

Purpose

– This paper aims to develop build strategies for rapid manufacturing of components of varying complexity with the help of illustration.

Design/methodology/approach

– The build strategies are developed using a hybrid layered manufacturing (HLM) setup. HLM, an automatic layered manufacturing process for metallic objects, combines the best features of two well-known and economical processes, viz., arc weld-deposition and milling. Depending on the geometric complexity of the object, the deposition and/or finish machining may involve fixed (3-axis) or variable axis (5-axis) kinematics.

Findings

– Fixed axis (3-axis) kinematics is sufficient to produce components free of undercuts and overhanging features. Manufacture of components with undercuts can be categorized into three methods, viz., those that exploit the inherent overhanging ability, those that involve blinding of the undercuts in the material deposition stage and those that involve variable axis kinematics for aligning the overhang with the deposition direction.

Research limitations/implications

– Although developed using the HLM setup, these generic concepts can be used in a variety of metal deposition processes.

Originality/value

– This paper describes the methodology for realizing undercut features of varying complexity and also chalks out the procedure for their manufacture with the help of case studies for each approach.
Process for reinforcing SLS parts by epoxy resin
Authors: Monzon Mario D. , Paz Rubén , Ortega Fernando , Chapela Jose A. , Conde Claudio
Published: April 2015

Purpose

– The purpose of this paper is to report on the use of a combination of selective laser sintering (SLS) and vacuum casting to create plastic composites made by additive manufacturing.

Design/methodology/approach

– The research has been carried out by approaching a new concept of the final part consistent in a plastic component, where the main body is made by SLS and the internal long fibres for reinforcing are made by vacuum casting of high-resistance epoxy resin. The part is designed for optimal number and distribution of the internal fibres taking into account the target relative stiffness (N/mm*kg). The methodology is applied to a pedal clutch of a car which has been tested in an equipment for fatigue and durability, being compared to the correspondent design for injection moulding.

Findings

– Research has proven that the approach introduces relevant improvement in mechanical properties of the base resin consistent in PA 3200GF (EOS), reinforced by internal long fibres of resin VG SP5. Experiments showed significant increase of stiffness in the pedal clutch made under this procedure, where the stiffness was 77 per cent higher than the conventional SLS part and only 11.7 per cent lower than the one made by injection moulding of PA 66 with 50 per cent fibreglass.

Originality/value

– The developed method introduces an alternative procedure for increasing the mechanical properties of plastic parts developed in SLS. Optimal orientation and distribution of long fibres clearly achieves better mechanical properties at low cost.
Comparing additive manufacturing technologies for customised wrist splints
Authors: Paterson Abby Megan , Bibb Richard , Campbell R. Ian , Bingham Guy
Published: April 2015

Purpose

– The purpose of this paper is to compare four different additive manufacturing (AM) processes to assess their suitability in the context of upper extremity splinting.

Design/methodology/approach

– This paper describes the design characteristics and subsequent fabrication of six different wrist splints using four different AM processes: laser sintering (LS), fused deposition modelling (FDM), stereolithography (SLA) and polyjet material jetting via Objet Connex. The suitability of each process was then compared against competing designs and processes from traditional splinting. The splints were created using a digital design workflow that combined recognised clinical best practice with design for AM principles.

Findings

– Research concluded that, based on currently available technology, FDM was considered the least suitable AM process for upper extremity splinting. LS, SLA and material jetting show promise for future applications, but further research and development into AM processes, materials and splint design optimisation is required if the full potential is to be realised.

Originality/value

– Unlike previous work that has applied AM processes to replicate traditional splint designs, the splints described are based on a digital design for AM workflow, incorporating novel features and physical properties not previously possible in clinical splinting. The benefits of AM for customised splint fabrication have been summarised. A range of AM processes have also been evaluated for splinting, exposing the limitations of existing technology, demonstrating novel and advantageous design features and opportunities for future research.
Development of an electrospinning-based rapid prototyping for scaffold fabrication
Authors: Chanthakulchan Apinya , Koomsap Pisut , Auyson Kampanat , Supaphol Pitt
Published: April 2015

Purpose

– This paper aims to present the development of an electrospinning-based rapid prototyping (ESRP) technique for the fabrication of patterned scaffolds from fine fiber.

Design/methodology/approach

– This ESRP technique unifies rapid prototyping (RP) and electrospinning to obtain the ability of RP to create a controllable pattern and of electrospinning to create a continuous fine fiber. The technique follows RP process of fused deposition modeling, but instead of using extrusion process for fiber creation, electrospinning is applied to generate a continuous fiber from a liquid solution. A machine prototype has been constructed and used in the experiments to evaluate the technique.

Findings

– Three different lay-down patterns: 0°/90°, 45°/135° and 45° twists were used in the experiments. According to the experimental results, stacks of patterned layers could be created with the ESRP technique, and the fabrication process was repeatable and reproducible. However, the existing machine vibration influenced the fiber size and the ability to control straightness and gap size. Also, incomplete solidification of the fibers prior to being deposited obstructed the control of layer thickness. Improvement on vibration suppression and fiber solidification will strengthen the capability of this ESRP technique.

Research limitations/implications

– This research is currently limited to the introduction of the ESRP technique, to the development of the machine prototype, to the demonstration of its capability and to the evaluation of the structural properties of the fabricated patterned scaffolds. Further studies are required for better control of the patterned scaffolds and for investigation of mechanical and biological properties.

Originality/value

– This unification of the two processes allows not only the fabrication of controllable patterned scaffolds but also the fabrication of both woven and non-woven layers of fibers to be done on one machine.
Geometrical feature analysis of Co-Cr-Mo single tracks after selective laser melting processing
Authors: Monroy Karla , Delgado Jordi , Sereno Lidia , Ciurana Joaquim , Hendrichs Nicolas J
Published: April 2015

Purpose

– Therefore, the purpose of this study is to understand the relationships between the processing parameters and the geometric form of the produced single tracks, in order to control dimensional quality in future experimentations. The quality of the deposited single track and layer is of prime importance in the selective laser melting (SLM) process, as it affects the product quality in terms of dimensional precision and product performance.

Design/methodology/approach

– In this paper, a vertical milling machining center equipped with an Ytterbium-fiber laser was used in the SLM experimentation to form single cobalt-chromium-molybdenum (CoCrMo) tracks. The different geometric features and the influence of the scanning parameters on these morphologic characteristics were studied statistically by means of ANOVA.

Findings

– Evidently, track height (h1) inaccuracy reduced in layer thicknesses between 100 and 200 μm. The re-melt depth (h2) was determined by the energy parameters, with laser power of 325-350 W and scanning speed (SS) of 66.6-83.3 mm/s being the most favorable parameters to obtain the required anchoring. Moreover, a contact angle of 117° was proposed as optimal, as it permitted an adequate overlapping region and a full densification, and, finally, an SS of 50 mm/s and a layer thickness of 250 were suggested for its development.

Originality/value

– The comprehension of the phenomena inherent to the process is related to the single track geometrical characteristics, which allow the definition of an optimal value for each factor for a further proposal of processing conditions that can finally derive a higher precision, wetting, density and mechanical properties.
Resilience of palm populations to disturbance is determined by interactive effects of fire, herbivory and harvest
Authors: Mandle Lisa , Ticktin Tamara , Zuidema Pieter A.
Published: April 2015

Little is known about the interactive effects of multiple forms of disturbance – natural or anthropogenic – on plant population dynamics. This limits our ability to understand the drivers of these dynamics and effectively manage plant populations in the face of changing disturbance regimes.

Fire, grazing and harvest of wild plants are three widespread, commonly co‐occurring land management activities in the tropics that contribute to altered disturbance regimes. In this study, we investigate the effects of and interactions among these activities on mountain date palm (Phoenix loureiroi) populations in the Western Ghats, India with data from 14 palm populations, including over 2300 palm ramets monitored from 2009 to 2011.

We construct integral projection models (IPMs) of palm population dynamics based on the response of palm individuals to fire and varying intensities of grazing and leaf harvest and carry out Markov Chain Monte Carlo simulations to understand the implications of different scenarios of disturbance for population persistence.

We find that palm individuals and populations were resilient to low levels of fire, grazing and harvest. There are also important interactions among these forms of disturbance: intensities of harvest and grazing are highest in populations one to two years after fire, and the intensity of harvest is lower in heavily grazed populations.

These interactions mean that the combined effects of multiple forms of disturbance differ from what would be assumed from simply adding their separate effects. While simulations show that sustained high intensities of harvest and grazing would have severely negative consequences for palm populations, interactions between these two forms of disturbance prevent palm populations from actually experiencing such extreme conditions. On the other hand, because intensities of grazing and harvest both increase moderately following fire, their combined negative effects on population growth rates are exacerbated by fire. Thus, multiple, interacting disturbances determine the resilience of these palm populations and the sustainability of their management.

Synthesis. This study illustrates the importance of explicitly incorporating realistic interactions among multiple forms of disturbance when evaluating plant populations' resilience to changing disturbance regimes and the sustainability of plant harvest.
Oral reading fluency and comprehension in Kenya: reading acquisition in a multilingual environment
Authors: Piper Benjamin , Schroeder Leila , Trudell Barbara
Published: April 2015

Reading research has shown that variable relationships exist between measures of oral reading fluency and reading comprehension, depending on whether the language of the text is the reader's first language or an additional language. This paper explores this phenomenon, using reading assessment data for 2,000 Kenyan children in two or three languages: English, Kiswahili and one of two mother tongues, Dholuo or Gikuyu. The assessment data allowed us to compare reading and comprehension rates across languages. The data indicated that many children could read English words more easily than words in Kiswahili or their mother tongue; nevertheless, their reading comprehension was significantly lower in English than in Kiswahili, Dholuo or Gikuyu. The paper concludes that emphasising English reading fluency is an inefficient route to gaining reading comprehension skills because pupils are actually attaining minimal oral reading fluency in English and only modest comprehension skills in their own languages. The evidence also demonstrates that Kenya's national language policy of mother tongue as a medium of instruction in the early primary grades is consistently ignored in practice.
Contrast‐enhanced spectral mammography (CESM) and contrast enhanced MRI (CEMRI): Patient preferences and tolerance
Authors: Hobbs Max M , Taylor Donna B , Buzynski Sebastian , Peake Rachel E
Published: April 2015

Introduction

Contrast‐enhanced spectral mammography (CESM) may have similar diagnostic performance to Contrast‐enhanced MRI (CEMRI) in the diagnosis and staging of breast cancer. To date, research has focused exclusively on diagnostic performance when comparing these two techniques. Patient experience is also an important factor when comparing and deciding on which of these modalities is preferable. The aim of this study is to compare patient experience of CESM against CEMRI during preoperative breast cancer staging.

Methods

Forty‐nine participants who underwent both CESM and CEMRI, as part of a larger trial, completed a Likert questionnaire about their preference for each modality according to the following criteria: comfort of breast compression, comfort of intravenous (IV) contrast injection, anxiety and overall preference. Participants also reported reasons for preferring one modality to the other. Quantitative data were analysed using a Wilcoxon sign‐rank test and chi‐squared test. Qualitative data are reported descriptively.

Results

A significantly higher overall preference towards CESM was demonstrated (n = 49, P < 0.001), with faster procedure time, greater comfort and lower noise level cited as the commonest reasons. Participants also reported significantly lower rates of anxiety during CESM compared with CEMRI (n = 36, P = 0.009). A significantly higher rate of comfort was reported during CEMRI for measures of breast compression (n = 49, P = 0.001) and the sensation of IV contrast injection (n = 49, P = 0.003).

Conclusion

Our data suggest that overall, patients prefer the experience of CESM to CEMRI, adding support for the role of CESM as a possible alternative to CEMRI for breast cancer staging.
PIPITS: an automated pipeline for analyses of fungal internal transcribed spacer sequences from the Illumina sequencing platform
Authors: Gweon Hyun S. , Oliver Anna , Taylor Joanne , Booth Tim , Gibbs Melanie , Read Daniel S. , Griffiths Robert I. , Schonrogge Karsten
Published: April 2015

Studying fungal biodiversity using data generated from Illumina MiSeq sequencing platforms poses a number of bioinformatic challenges with the analysis typically involving a large number of tools for each analytical step from quality filtering to generating identified operational taxonomic unit (OTU) abundance tables.

Here, we introduce PIPITS, an open‐source stand‐alone suite of software for automated processing of Illumina MiSeq sequences for fungal community analysis. PIPITS exploits a number of state of the art applications to process paired‐end reads from quality filtering to producing OTU abundance tables.

We provide detailed descriptions of the pipeline and show its utility in the analysis of 9 396 092 sequences generated on the MiSeq platform from Illumina MiSeq.

PIPITS is the first automated bioinformatics pipeline dedicated for fungal ITS sequences which incorporates ITSx to extract subregions of ITS and exploits the latest RDP Classifier to classify sequences against the curated UNITE fungal data set.
History and current status of bariatric and metabolic surgeries in East Asia
Authors: Umemura Akira , Lee Wei‐Jei , Sasaki Akira , Wakabayashi Go
Published: April 2015

Morbid obesity and obesity‐related comorbidities are major public health problems around the world, including in East Asia. Although Asian populations have been shown to have an elevated risk of type 2 diabetes mellitus, hypertension, and hyperlipidemia at a relatively lower BMI than Western populations, the Asian perspective on bariatric and metabolic surgeries has not been actively discussed until recently. Bariatric surgery in East Asia has undergone a paradigm shift since the first laparoscopic vertical bariatric surgery was performed in Taiwan in 1998, which was subsequently followed by the introduction of laparoscopic adjustable gastric banding, Roux‐en‐Y gastric bypass, and mini‐gastric bypass. Since 2006, use of laparoscopic sleeve gastrectomy has remarkably increased because of its ease, speed, and safety. With regard to metabolic surgery, a randomized controlled trial in Taiwan demonstrated that laparoscopic Roux‐en‐Y gastric bypass is more effective than laparoscopic sleeve gastrectomy for surgical treatment of poorly controlled type 2 diabetes mellitus and metabolic syndrome. In this article, we describe the history of bariatric procedures, revision surgeries, weight‐loss effect, and metabolic surgeries in Asian populations, and we also discuss minimally invasive bariatric surgery with some important citations.
Incretin secretion in obese Korean children and adolescents with newly diagnosed type 2 diabetes
Authors: Park So Hyun , Jung Min Ho , Cho Won Kyoung , Park Mi Sun , Suh Byung Kyu
Published: April 2015

Objective

The role of incretins in type 2 diabetes is controversial. This study investigated the association between incretin levels in obese Korean children and adolescents newly diagnosed with type 2 diabetes.

Design

We performed a 2‐hr oral glucose tolerance test (OGTT) in obese children and adolescents with type 2 diabetes and with normal glucose tolerance.

Patients

Twelve obese children and adolescents with newly diagnosed type 2 diabetes (DM group) and 12 obese age‐matched subjects without type 2 diabetes (NDM group) were included.

Measurements

An OGTT was conducted and insulin, C‐peptide, glucagon, glucagon‐like peptide‐1 (GLP‐1) and glucose‐dependent insulinotropic polypeptide (GIP) were measured during the OGTT.

Results

The mean age of the patients was 13·8 ± 2·0 years, and the mean body mass index (BMI) Z‐score was 2·1 ± 0·5. The groups were comparable in age, sex, BMI Z‐score and waist:hip ratio. The DM group had significantly lower homeostasis model assessment of β and insulinogenic index values (P < 0·001). The homeostasis model assessment of insulin resistance index was not different between the two groups. Insulin and C‐peptide secretions were significantly lower in the DM group than in the NDM group (P < 0·001). Total GLP‐1 secretion was significantly higher in the DM group while intact GLP‐1 and GIP secretion values were not significantly different between the two groups.

Conclusion

Impaired insulin secretion might be important in the pathogenesis of type 2 diabetes in obese Korean children and adolescents, however, which may not be attributed to incretin secretion.
Cerebral glucose metabolism in the striate cortex positively correlates with fractional anisotropy values of the optic radiation in patients with glaucoma
Authors: Murai Hideki , Suzuki Yukihisa , Kiyosawa Motohiro , Tokumaru Aya M , Ishiwata Kiichi , Ishii Kenji
Published: April 2015

Background

It has recently become clear that glaucoma is not only an ocular disease, but involves central visual pathways as well. The purpose of this study was to examine functional and structural alterations in the brains of glaucoma patients.

Design

Case–control study in a hospital.

Participants

A total of 32 glaucoma patients and 19 healthy controls.

Methods

All participants underwent positron emission tomography with 18F‐fluorodeoxyglucose, diffusion‐tensor magnetic resonance imaging, and the 30‐2 program of the Humphrey Visual Field Analyzer.

Main Outcome Measures

Fractional anisotropy values of the optic radiation were compared between the two groups by defining regions of interests. Cerebral glucose metabolism was compared using statistical parametric mapping software. The correlation coefficients were calculated between the average of the total deviation of hemivisual fields of both eyes, fractional anisotropy values of the contralateral optic radiation and glucose metabolism in the contralateral striate cortex.

Results

Fractional anisotropy values in the bilateral optic radiations were significantly lower in patients with glaucoma. A significant glucose hypometabolism in the bilateral striate cortex was also observed in the glaucoma group. Regression analyses for glaucoma patients demonstrated that the average of the total deviation of hemivisual fields significantly correlated with both fractional anisotropy value of the contralateral optic radiation and glucose metabolism in the contralateral striate cortex. Moreover, there were significant correlations between fractional anisotropy values of the optic radiation and ipsilateral striatal glucose metabolism.

Conclusion

We observed structural alterations in the bilateral optic radiations and glucose hypometabolism in the bilateral striate cortex of glaucoma patients.
Growth patterns of Chinese patients with Prader‐Willi syndrome
Authors: Yang Hongbo , Zhang Mengqi , Song Hongmei , Zhu Huijuan , Pan Hui
Published: April 2015

The aim of the present study was to investigate the spontaneous development of growth and weight gain of patients with Prader‐Willi syndrome (PWS) in Mainland China. We retrospectively analyzed 120 cases of PWS diagnosed from 1994 to 2014 in Mainland China. Scatter diagram of the growth data was compared to standardized growth curve. The length at birth was similar to the normal population and the mean birthweight is under the 50th centile of normal population. Heights in 43% (27/62) of patients had dropped off below the 3rd centile of their peers after 5 years of age. Weights in 65.9% (58/88) of patients had exceeded the 97th centile of their peers after 3 years of age. Early obesity is obvious in 92.9% (66/71) of patients with body mass index (BMI) up the 97th centile of their peers from 2–3 years of age. Final mean height is 149.3 ± 11.2 cm for females (n = 7) and 146.2 ± 9.8 cm for males (n = 6), showing 11.3 cm and 26.6 cm below the average height for normal Chinese girls and boys. The growth pattern of PWS in Mainland China is comparable to those in Caucasians. Early intervention with recombinant human growth hormone is warranted considering the early onset of growth retardation and obesity.
Characteristics of 2p15‐p16.1 microdeletion syndrome: Review and description of two additional patients
Authors: Shimojima Keiko , Okamoto Nobuhiko , Yamamoto Toshiyuki
Published: April 2015

Many new microdeletion syndromes have been characterized in the past decade, including 2p15‐p16.1 microdeletion syndrome. More than 10 patients with this syndrome have been described. Recently, we encountered two additional patients with 2p15‐p16.1 microdeletion syndrome. All patients showed variable degrees of intellectual disability, with the autistic features characteristic of this syndrome. Seven out of 16 patients (44%) showed structural abnormalities in the brain, which is also an important feature of this syndrome. The shortest region of microdeletion overlap among the patients includes two genes, USP34 and XPO1. Although these genes have some functional relevance to cancer, they have not been associated with neurological functions. Diagnosis of additional patients with 2p15‐p16.1 microdeletion syndrome and identification of pathogenic mutations in this region will help identify the genes responsible for the neurological features of the syndrome.
The Risk–Return Binomial After Rating Changes
Authors: Abad Pilar , Robles M. Dolores
Published: April 2015

Risk‐averse investors consider the risk–return trade‐off when determining their new position after the release of relevant information. This paper analyses the informational content of rating change announcements, focusing on the joint effect they have on the risk–return binomial. Our purpose is to identify the main factors that signal which announcements are informative. To do so, we estimate a binomial logit model for the probability that credit rating announcements contain informational content. We analyse a sample of rating events affecting Spanish listed firms from 2000 to 2010. The empirical results reveal significant differences in informational content between positive and negative rating events. For both types of announcements, we observe higher informational content when agencies agree on the new level of solvency, whereas announcements regarding highly covered firms that operate in highly regulated sectors are less informative. Other factors such as the presence of previous rating refinements or trends in credit quality reveal different information depending on the direction of the rating event. Finally, we find that announcements after the crisis disclose less information, suggesting a loss of reputation among credit rating agencies.
Lean‐season primary productivity and heat dissipation as key drivers of geographic body‐size variation in a widespread marsupial
Authors: Correll Rachel A. , Prowse Thomas A. A. , Prideaux Gavin J.
Published: April 2015

Geographic body‐size variation characterises many mammal species. Hypotheses centring around heat conservation, heat dissipation, primary productivity and seasonality have been advanced to explain geographic body‐size patterns. However, identification of the primary body‐size drivers has often been hampered by a paucity of data for broadly distributed species and the application of regression models that have not explicitly accounted for the spatial clustering inherent in such datasets. We used Australia's most widespread marsupial, the common brushtail possum Trichosurus vulpecula, as a model species with which to test five proposed drivers of geographic body‐size variation. Using geo‐referenced skull measurements from 588 specimens and a suite of putative environmental covariates, we employed spatial simultaneous autoregressive models, together with information criteria, to evaluate these different hypotheses. Our analysis identified a strong, positive relationship between possum body size and primary productivity during the least productive season, whereas the relationship with mean annual productivity received less support. Consistent with the heat‐dissipation hypothesis, T. vulpecula body size also decreased with increasing mean summer maximum temperature. Spatial autoregression coefficients estimated from the simultaneous autoregressive models were always high, suggesting that additional abiotic or biotic factors might contribute to the spatial patterns observed. We argue that the analysis of geographic body‐size variation should consider multi‐causal possibilities rather than treating the numerous hypotheses as competing, mutually exclusive alternatives.
Global geographic patterns of sexual size dimorphism in birds: support for a latitudinal trend?
Authors: Friedman Nicholas R. , Remeš Vladimír
Published: April 2015

Sexual size dimorphism (SSD) is widespread among animals, and is a common indication of differential selection among males and females. Sexual selection theory predicts that SSD should increase as one sex competes more fiercely for access to mates, but it is unclear what effect spatial variation in ecology may have on this behavioral process and SSD. Here, we examine SSD across the class Aves in a spatial and phylogenetic framework, and test several a priori hypotheses regarding its relationship with climate. We mapped the global distribution of SSD from published descriptions of body size, distribution, and phylogenetic relationships across 2581 species of birds. We examined correlations between SSD and nine predictor variables representing a priori models of physical geography, climate, and climate variability. Our results show some support for a global latitudinal trend in SSD based on a weak prevalence of species with low or female‐biased SSD in the north, but substantial spatial heterogeneity. While several stronger relationships were observed between SSD and climate predictors within zoogeographical regions, no global relationship emerged that was consistent across multiple methods of analysis. The strong phylogenetic signal and conspicuous lack of support from phylogenetically corrected analyses suggests that any such relationship in birds is likely obscured by the idiosyncratic histories of different lineages. In this manner, our results agree with previous studies in other clades, leading us to conclude that the relationship between climate and SSD is at best complex. This suggests that SSD, and the behavioral dynamics underlying it, may be largely independent of environmental conditions at a global scale.
Serum antinuclear antibody may be associated with less severe disease activity in neuromyelitis optica
Authors: Masuda H. , Mori M. , Uzawa A. , Muto M. , Uchida T. , Kuwabara S.
Published: April 2015

Background and purpose

Antinuclear antibody‐positive multiple sclerosis (MS) patients have shorter disease duration and lower Expanded Disability Status Scale (EDSS) scores. The aim of this study was to compare clinical and laboratory features between MS and neuromyelitis optica (NMO) patients with and without autoantibodies and to investigate the prognosis of NMO in patients with and without autoantibodies.

Methods

The frequencies of antinuclear, anti‐Sjögren's syndrome A (SSA)/Ro, anti‐Sjögren's syndrome B (SSB)/La and anti‐thyroid peroxidase (TPO) antibodies in the sera of 75 NMO patients and 131 MS patients were compared. Clinical and laboratory profiles were also compared between NMO patients with and without autoantibodies, including annual relapse rate and time from onset of NMO to EDSS scores of 4.0 (limited walking but without aid) and 6.0 (walking with unilateral aid).

Results

More NMO than MS patients had antinuclear and anti‐SSA/Ro antibodies (31% vs. 10%, P < 0.001, and 21% vs. 3%, P < 0.001, respectively). Antinuclear antibody‐positive NMO patients had a lower annual relapse rate from disease onset to serum sampling compared with antinuclear antibody‐negative NMO patients, independent of treatment regimen. Antinuclear antibody‐negative NMO patients reached an EDSS score of 6.0 earlier than antinuclear antibody‐positive NMO patients (P = 0.026). Cerebrospinal fluid cell counts were higher in anti‐SSA/Ro‐positive than in anti‐SSA/Ro‐negative NMO patients. More anti‐TPO antibody‐positive than anti‐TPO antibody‐negative NMO patients had oligoclonal immunoglobulin G bands (60% vs. 11%, P = 0.048).

Conclusions

Autoantibodies possibly modulate the pathophysiology of NMO. Antinuclear antibody may be associated with less severe disease activity or less disability in NMO.
Cognitive impairment in a population‐based study of patients with multiple sclerosis: differences between late relapsing−remitting, secondary progressive and primary progressive multiple sclerosis
Authors: Planche V. , Gibelin M. , Cregut D. , Pereira B. , Clavelou P.
Published: April 2015

Background and purpose

Few studies have investigated the differences in cognitive skills between the three subtypes of multiple sclerosis (MS) and they confounded the course of the disease with the duration of the disease and the physical disability. Moreover, they were not population based.

Methods

This was a retrospective analysis of cognitive testing from the database of a French programme for MS care. The pattern and the frequency of cognitive impairment in secondary progressive (SP), primary progressive (PP) and late relapsing−remitting (LRR, disease duration of more than 10 years) MS were compared.

Results

A total of 101 patients with MS (41 LRRMS, 37 SPMS, 23 PPMS) were included. 63.0% had a significant cognitive impairment. After controlling for age, sex, Expanded Disability Status Scale, disease duration and education level, patients with SPMS were at least 2‐fold more frequently impaired than patients with LLRMS in information processing speed (P = 0.005), executive functions (P = 0.04), verbal fluency (P = 0.02), verbal episodic memory (P = 0.04), working memory (P = 0.02) and visuospatial construction (P = 0.01). The number of patients with at least one or two deficient cognitive domain(s) was higher in the SPMS group than in the LRRMS group (P = 0.002 and P < 0.001). Patients with PPMS were more frequently impaired in verbal fluency (P = 0.046) than patients with LRRMS and they more often presented at least one impaired cognitive domain (P = 0.03). SPMS and PPMS groups differed only for visuospatial construction (P = 0.02).

Conclusion

In this population‐based study, patients with a progressive subtype of MS were more frequently and more severely impaired than patients with RRMS, even after more than 10 years of disease.
Early magnetic resonance imaging predictors of clinical progression after 48 months in clinically isolated syndrome patients treated with intramuscular interferon β‐1a
Authors: Uher T. , Horakova D. , Kalincik T. , Bergsland N. , Tyblova M. , Ramasamy D. P. , Seidl Z. , Vaneckova M. , Krasensky J. , Havrdova E. , Zivadinov R.
Published: April 2015

Background and purpose

Our aim was to identify early imaging surrogate markers of clinical progression in patients after the first demyelinating event suggestive of multiple sclerosis treated with weekly intramuscular interferon β‐1a. In a prospective observational study, the predictive role of baseline and 6‐month changes in magnetic resonance imaging outcomes was investigated with respect to relapse activity and development of confirmed disability progression in patients after 48 months.

Methods

This study examined 210 patients. Multivariate Cox proportional hazard models were used to analyse predictors of relapse activity and confirmed disability progression after 48 months.

Results

Greater T2 lesion volume [hazard ratio (HR) 1.81; P = 0.005] and the presence of contrast‐enhancing lesions (HR 2.13; P < 0.001) at baseline were significantly associated with increased cumulative risk of a second clinical attack over 48 months. A greater decrease of the corpus callosum volume (HR 2.74; P = 0.001) and greater lateral ventricle volume enlargement (HR 2.43; P = 0.002) at 6 months relative to baseline were associated with increased cumulative risk of a second clinical attack between months 6 and 48. In addition, increased risk of confirmed disability progression over 48 months in patients with greater lateral ventricle volume enlargement between baseline and 6 months (HR 4.70; P = 0.001) was detected.

Conclusions

A greater T2 lesion volume, the presence of contrast‐enhancing lesions at baseline, decrease of corpus callosum volume and lateral ventricle volume enlargement over the first 6 months in patients after the first demyelinating event treated with weekly intramuscular interferon β‐1a may assist in identification of patients with the highest risk of a second clinical attack and progression of disability.