bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoluminescence enhancement in CdS quantum dots by thermal annealing
Authors: Kim Jae Ik , Kim Jongmin , Lee Junhee , Jung Dae-Ryong , Kim Hoechang , Choi Hongsik , Lee Sungjun , Byun Sujin , Kang Suji , Park Byungwoo 
Published: October 2012

Abstract
The photoluminescence behavior of CdS quantum dots in initial growth stage was studied in connection with an annealing process. Compared to the as-synthesized CdS quantum dots (quantum efficiency ≅ 1%), the heat-treated sample showed enhanced luminescence properties (quantum efficiency ≅ 29%) with a narrow band-edge emission. The simple annealing process diminished the accumulated defect states within the nanoparticles and thereby reduced the nonradiative recombination, which was confirmed by diffraction, absorption, and time-resolved photoluminescence. Consequently, the highly luminescent and defect-free nanoparticles were obtained by a facile and straightforward process.
Solving certain classes of Lane-Emden type equations using the differential transformation method
Authors: Khan Yasir , Svoboda Zdeněk , Šmarda Zdeněk 
Published: October 2012

Abstract
In this paper, the differential transformation method (DTM) is applied to solve singular initial problems represented by certain classes of Lane-Emden type equations. Some new differential transformation formulas for certain exponential and logarithmic nonlinearities are derived. The approximate and exact solutions of these equations are calculated in the form of series with easily computable terms. The results obtained with the proposed methods are in good agreement with those obtained by other methods. The advantages of this technique are shown as well.
Toward attenuating the impact of arm positions on electromyography pattern-recognition based motion classification in transradial amputees
Authors: Geng Yanjuan , Zhou Ping , Li Guanglin 
Published: October 2012

Abstract

Background
Electromyography (EMG) pattern-recognition based control strategies for multifunctional myoelectric prosthesis systems have been studied commonly in a controlled laboratory setting. Before these myoelectric prosthesis systems are clinically viable, it will be necessary to assess the effect of some disparities between the ideal laboratory setting and practical use on the control performance. One important obstacle is the impact of arm position variation that causes the changes of EMG pattern when performing identical motions in different arm positions. This study aimed to investigate the impacts of arm position variation on EMG pattern-recognition based motion classification in upper-limb amputees and the solutions for reducing these impacts.

Methods
With five unilateral transradial (TR) amputees, the EMG signals and tri-axial accelerometer mechanomyography (ACC-MMG) signals were simultaneously collected from both amputated and intact arms when performing six classes of arm and hand movements in each of five arm positions that were considered in the study. The effect of the arm position changes was estimated in terms of motion classification error and compared between amputated and intact arms. Then the performance of three proposed methods in attenuating the impact of arm positions was evaluated.

Results
With EMG signals, the average intra-position and inter-position classification errors across all five arm positions and five subjects were around 7.3% and 29.9% from amputated arms, respectively, about 1.0% and 10% low in comparison with those from intact arms. While ACC-MMG signals could yield a similar intra-position classification error (9.9%) as EMG, they had much higher inter-position classification error with an average value of 81.1% over the arm positions and the subjects. When the EMG data from all five arm positions were involved in the training set, the average classification error reached a value of around 10.8% for amputated arms. Using a two-stage cascade classifier, the average classification error was around 9.0% over all five arm positions. Reducing ACC-MMG channels from 8 to 2 only increased the average position classification error across all five arm positions from 0.7% to 1.0% in amputated arms.

Conclusions
The performance of EMG pattern-recognition based method in classifying movements strongly depends on arm positions. This dependency is a little stronger in intact arm than in amputated arm, which suggests that the investigations associated with practical use of a myoelectric prosthesis should use the limb amputees as subjects instead of using able-body subjects. The two-stage cascade classifier mode with ACC-MMG for limb position identification and EMG for limb motion classification may be a promising way to reduce the effect of limb position variation on classification performance.
Exploration of ‘hot-spots’ of methane and nitrous oxide emission from the agriculture fields of Assam, India
Authors: Mishra Satyendra Nath , Mitra Sudip , Rangan Latha , Dutta Subashisha , Singh Pooja 
Published: October 2012

Abstract

Background
Agricultural soils contribute towards the emission of CH4 (mainly from paddy fields) and N2O (from N-fertilizer application), the two important greenhouse gases causing global warming. Most studies had developed the inventories of CH4 and N2O emission at the country level (larger scale) for India, but not many studies are available at the local scale (e.g. district level) on these greenhouse gases (GHGs). Assam is an important state in the North Eastern region of India. In addition to being the regional economic hub for the entire region, agriculture is the major contributor to the state’s gross domestic product. In Assam about three-fourths of the area is under paddy cultivation and rice is the staple food. With this background, a district wise inventory of CH4 and N2O emission in the North Eastern state of Assam, India was carried out using different emission factors, viz., IPCC, Indian factors and others, to highlight the discrepancies that arose in the emission estimation of these important GHGs while used at the smaller scale i.e. district level. This study emphasizes the need for better methodologies at the local level for GHGs inventories. This study also reiterates the fact that no emission factor is universally applicable across all regions. The GHGs like CH4 and N2O are highly site and crop specific and the factors required for their inventory are driven by cultural practices, agronomic management, soil resources and socio-economic drivers.

Material and methods
In this study, Intergovernmental Panel on Climate Change (IPCC) methodology was used for the estimation of CH4 and N2O emission. In case of N2O emission, both direct and indirect emission from agricultural soil was estimated for the various districts of Assam.

Results
The CH4 (base year 2000–2001) and N2O (base year 2001–2002) emission was estimated to be 121 Gg and 1.36 Gg from rice paddy and agricultural fields of Assam state respectively.

Conclusions
This study is the first report on the estimation of the GHG emission at the district level from the entire state of Assam, agriculturally one very important state of North Eastern India. This state is also considered as remote due to its geographical location. The study clearly elucidates that there is large variation in the emission inventory of CH4 and N2O at the district level (local scale) when different emission factors are used. This calls for detailed and comprehensive data collection and mapping at the micro level for accurate inventory of greenhouse gases in future from agriculture fields.
View: implementing low cost air quality monitoring solution for urban areas
Authors: Ikram Jahangir , Tahir Amer , Kazmi Hasanat , Khan Zonia , Javed Rabi , Masood Usama 
Published: October 2012

Abstract

Background
Air pollution represents non uniform trends particularly in dense urban areas which arises the necessity for pollution monitoring at finer resolution. Since recent advancements in electrochemical technology have made it feasible to deploy economical wireless sensor nodes for environmental monitoring, we present a bed of cost effective referential sensors which replace the role of traditional weather stations. The system is intended to target lower income nations like Pakistan, where air pollution monitoring and regulation is a crucial issue, not receiving appropriate attention.

Results
The project is specifically designed to be cost effective, compact, energy efficient and possesses the ability to be deployed in large numbers to overcome the limitations of conventional static environment monitoring sites. We have developed a system which aims at increasing awareness to the average citizen and policy makers regarding the prevailing environmental conditions. We go on to investigate the feasibility, reliability and accuracy of the project when deployed in an urban setting. Here we provide a brief summary on the calibration techniques we employed to achieve accurate results, along with providing details on the future research and development with respect to the project.

Conclusion
The model proposed, was used to pilot a venture in Lahore, Pakistan and is deployed successfully.
Mineralizing Enthesopathy Is a Common Feature of Renal Phosphate-Wasting Disorders Attributed to FGF23 and Is Exacerbated by Standard Therapy in Hyp Mice
Authors: Karaplis Andrew C. , Bai Xiuying , Falet Jean-Pierre , Macica Carolyn M. 
Published: October 2012

Abstract
We have previously confirmed a paradoxical mineralizing enthesopathy as a hallmark of X-linked hypophosphatemia. X-linked hypophosphatemia is the most common of the phosphate-wasting disorders mediated by elevated fibroblast growth factor 23 (FGF23) and occurs as a consequence of inactivating mutations of the PHEX gene product. Despite childhood management of the disease, these complications of tendon and ligament insertion sites account for a great deal of the disease's morbidity into adulthood. It is unclear whether the enthesopathy occurs in other forms of renal phosphate-wasting disorders attributable to high FGF23 levels. Here we describe two patients with autosomal recessive hypophosphatemic rickets due to the Met1Val mutation in dentin matrix acidic phosphoprotein 1 (DMP1). In addition to the biochemical and skeletal features of long-standing rickets with elevated FGF23 levels, these individuals exhibited severe, debilitating, generalized mineralized enthesopathy. These data suggest that enthesophytes are a feature common to FGF23-mediated phosphate-wasting disorders. To address this possibility, we examined a murine model of FGF23 overexpression using a transgene encoding the secreted form of human FGF23 (R176Q) cDNA (FGF23-TG mice). We report that FGF23-TG mice display a similar mineralizing enthesopathy of the Achilles and plantar facial insertions. In addition, we examined the impact of standard therapy for phosphate-wasting disorders on enthesophyte progression. We report that fibrochondrocyte hyperplasia persisted in Hyp mice treated with oral phosphate and calcitriol. In addition, treatment had the untoward effect of further exacerbating the mineralization of fibrochondrocytes that define the bone spur of the Achilles insertion. These studies support the need for newer interventions targeted at limiting the actions of FGF23 and minimizing both the toxicities and potential morbidities associated with standard therapy.
Restricted diffusion of OXPHOS complexes in dynamic mitochondria delays their exchange between cristae and engenders a transitory mosaic distribution
Authors: Wilkens Verena , Kohl Wladislaw , Busch Karin 
Published: October 2012

Summary
Mitochondria are involved in cellular energy supply, signaling and apoptosis. Their ability to fuse and divide provides functional and morphological flexibility and is a key feature in mitochondrial quality maintenance. To study the impact of mitochondrial fusion/fission on the reorganization of inner membrane proteins, oxidative phosphorylation (OXPHOS) complexes in mitochondria of different HeLa cells were tagged with fluorescent proteins (GFP and DsRed-HA), and cells were fused by polyethylene glycol treatment. Redistribution of the tagged OXPHOS complexes was then followed by means of immunoelectron microscopy, two color super-resolution fluorescence microscopy and single molecule tracking. In contrast to outer membrane and matrix proteins, which mix quickly and homogeneously upon mitochondrial fusion, the mixing of inner membrane proteins was decelerated. Our data suggest that the composition of cristae is preserved during fusion of mitochondria and that cristae with mixed OXPHOS complexes are only slowly and successively formed by restricted diffusion of inner membrane proteins into existing cristae. The resulting transitory mosaic composition of the inner mitochondrial membrane illuminates mitochondrial heterogeneity and potentially is linked to local differences in function and membrane potential.
The Hippo pathway member Yap plays a key role in influencing fate decisions in muscle satellite cells
Authors: Judson Robert N. , Tremblay Annie M. , Knopp Paul , White Robert B. , Urcia Roby , De Bari Cosimo , Zammit Peter S. , Camargo Fernando D. , Wackerhage Henning 
Published: October 2012

Summary
Satellite cells are the resident stem cells of skeletal muscle. Mitotically quiescent in mature muscle, they can be activated to proliferate and generate myoblasts to supply further myonuclei to hypertrophying or regenerating muscle fibres, or self-renew to maintain the resident stem cell pool. Here, we identify the transcriptional co-factor Yap as a novel regulator of satellite cell fate decisions. Yap expression increases during satellite cell activation and Yap remains highly expressed until after the differentiation versus self-renewal decision is made. Constitutive expression of Yap maintains Pax7+ and MyoD+ satellite cells and satellite cell-derived myoblasts, promotes proliferation but prevents differentiation. In contrast, Yap knockdown reduces the proliferation of satellite cell-derived myoblasts by ≈40%. Consistent with the cellular phenotype, microarrays show that Yap increases expression of genes associated with Yap inhibition, the cell cycle, ribosome biogenesis and that it represses several genes associated with angiotensin signalling. We also identify known regulators of satellite cell function such as BMP4, CD34 and Myf6 (Mrf4) as genes whose expression is dependent on Yap activity. Finally, we confirm in myoblasts that Yap binds to Tead transcription factors and co-activates MCAT elements which are enriched in the proximal promoters of Yap-responsive genes.
The motor protein myosin 1G functions in FcγR-mediated phagocytosis
Authors: Dart Anna E. , Tollis Sylvain , Bright Michael D. , Frankel Gad , Endres Robert G. 
Published: October 2012

Summary
Phagocytosis is the force-dependent complex cellular process by which immune cells engulf particles. Although there has been considerable progress in understanding ligand-receptor-induced actin polymerisation in pushing the membrane around the particle, significantly less is known about how localised contractile activities regulate cup closure in coordination with the actin cytoskeleton. Herein, we show that the unconventional class-I myosin, myosin 1G (Myo1G) is localised at phagocytic cups following Fcγ-receptor (FcγR) ligation in macrophages. This progressive recruitment is dependent on the activity of phosphoinositide 3-kinase and is particularly important for engulfment of large particles. Furthermore, point mutations in the conserved pleckstrin homology-like domain of Myo1G abolishes the localisation of the motor protein at phagocytic cups and inhibits engulfment downstream of FcγR. Binding of Myo1G to both F-actin and phospholipids might enable cells to transport phospholipids towards the leading edge of cups and to facilitate localised contraction for cup closure.
N-terminal horseshoe conformation of DCC is functionally required for axon guidance and might be shared by other neural receptors
Authors: Chen Qiang , Sun Xiaqin , Zhou Xiao-hong , Liu Jin-huan , Wu Jane , Zhang Yan , Wang Jia-huai 
Published: October 2012

Summary
Deleted in colorectal cancer (DCC) is a receptor for the axon guidance cues netrin-1 and draxin. The interactions between these guidance cues and DCC play a key role in the development of the nervous system. In the present study, we reveal the crystal structure of the N-terminal four Ig-like domains of DCC. The molecule folds into a horseshoe-like configuration. We demonstrate that this horseshoe conformation of DCC is required for guidance-cue-mediated axonal attraction. Structure-based mutations that disrupt the DCC horseshoe indeed impair its function. A comparison of the DCC horseshoe with previously described horseshoe structures has revealed striking conserved structural features and important sequence signatures. Using these signatures, a genome-wide search allows us to predict the N-terminal horseshoe arrangement in a number of other cell surface receptors, nearly all of which function in the nervous system. The N-terminal horseshoe appears to be evolutionally selected as a platform for neural receptors.
Hypoxia induces downregulation of soluble guanylyl cyclase β1 by miR-34c-5p
Authors: Xu Xiaojian , Wang Shumin , Liu Juan , Dou Dou , Liu Limei , Chen Zhengju , Ye Liping , Liu Huixia , He Qiong , Raj J. Usha , Gao Yuansheng 
Published: October 2012

Summary
Soluble guanylyl cyclase (sGC) is the principal receptor for nitric oxide (NO) and crucial for the control of various physiological functions. The β1 subunit of sGC is obligatory for the biological stability and activity of the sGC heterodimer. MicroRNAs (miRNAs) are important regulators of gene expression and exert great influences on diverse biological activities. The aim of the present study was to determine whether or not the expression of sGCβ1 is specifically regulated by miRNAs. We report that miR-34c-5p directly targets sGCβ1 under hypoxia. Bioinformatics analysis of the sGCβ1 3′-untranslated region (3′-UTR) revealed a putative binding site for miR-34b-5p and miR-34c-5p, but only miR-34c-5p inhibited luciferase activity through interaction with sGCβ1 3′-UTR in HEK293T cells. Site-directed mutagenesis of the putative miR-34c-5p binding site abolished the negative regulation of luciferase expression. Overexpression of miR-34c-5p repressed the expression of sGCβ1 in stable cell lines, which was reversed by miR-34c-5p-specific sponge. Inoculation of mouse lung tissues in vitro with lentivirus bearing miR-34c-5p significantly decreased both the expression of sGCβ1 and NO-stimulated sGC activity, which was also rescued by miR-34c-5p-specific sponge. Furthermore, we identified the putative Sp1-binding site in the promoter region of miR-34c-5p. Luciferase reporter constructs revealed that Sp1 directly binds to the wild-type promoter of miR-34c-5p, which was confirmed by chromatin immunoprecipitation. In summary, these findings reveal that miR-34c-5p directly regulates sGCβ1 expression, and they identify the key transcription factor Sp1 that governs miR-34c-5p expression during hypoxia.
Low O2 acclimation shifts the hypoxia avoidance behaviour of snapper (Pagrus auratus) with only subtle changes in aerobic and anaerobic function
Authors: Cook Denham G. , Iftikar Fathima I. , Baker Daniel W. , Hickey Anthony J.R. , Herbert Neill A. 
Published: October 2012

Summary
It was hypothesized that chronic hypoxia acclimation (preconditioning) would alter the behavioural low O2 avoidance strategy of fish as a result of both aerobic and anaerobic physiological adaptations. Avoidance and physiological responses of juvenile snapper (Pagrus auratus) were therefore investigated following a 6 week period of moderate hypoxia exposure (10.2-12.1 kPa PO2, 21 ± 1°C) and compared to those of normoxic controls (PO2= 20-21 kPa, 21 ± 1°C). The critical oxygen pressure (i.e. Pcrit) limit of both groups was unchanged at ~7 kPa, as were standard, routine and maximum metabolic rates. However, hypoxia acclimated fish showed increased tolerances to hypoxia in behavioral choice chambers by avoiding lower PO2 levels (3.3 ± 0.7 vs 5.3 ± 1.1 kPa) without displaying greater perturbations of lactate or glucose. This behavioural change was associated with unexpected physiological adjustments. For example, a decrease in blood O2 carrying capacity was observed after hypoxia-acclimation. Also unexpected was an increase in whole blood P50 following acclimation to low O2, perhaps facilitating Hb-O2 off-loading to tissues. In addition, cardiac mitochondria measured in situ using permeabilised fibres showed improved O2 uptake efficiencies. The proportion of the anaerobic enzyme lactate dehydrogenase (LDH), at least relative to the aerobic marker enzyme citrate synthase (CS), also increased in heart and skeletal red muscle indicating enhanced anaerobic potential, or in situ lactate metabolism, in these tissues. Overall these data suggest that a prioritization of O2 delivery and O2 utilization over O2 uptake during long-term hypoxia may convey a significant survival benefit to snapper in terms of behavioural low O2 tolerance.
Mechanics of snout expansion in suction feeding seahorses: musculoskeletal force transmission
Authors: Van Wassenbergh Sam , Leysen Heleen , Adriaens Dominique , Aerts Peter 
Published: October 2012

SummarySeahorses and other sygnathid fishes rely on a widening of the snout to create the buccal volume increase needed to suck prey into the mouth. This snout widening is caused by abduction of the suspensoria, the long and flat bones outlining the lateral sides of the mouth cavity. However, it remains unknown how seahorses can generate a forceful abduction of the suspensoria. To understand how force is transmitted to the suspensoria via the hyoid and the lower jaw, we performed mathematical simulations with models based on CT-scans of Hippocampus reidi. Our results show that the hinge joint between the left and right hyoid bars, as observed in H. reidi, allows for an efficient force transmission to the suspensorium from a wide range of hyoid angles, including the extremely retracted hyoid orientations observed in-vivo for syngnathids. Apart from the hyoid retraction force by the sternohyoideus-hypaxial muscles, force generated in the opposite direction on the hyoid by the mandibulohyoid ligament also has an important contribution to suspensorium abduction torque. Forces on the lower jaw contribute only for about 10% of the total suspensorium torque. In particular when dynamical aspects of hyoid retraction are included in the model, a steep increase is shown in suspensorium abduction torque at highly retracted hyoid positions, when the linkages to the lower jaw counteract further hyoid rotation in the sagittal plane. A delayed strain in these linkages allows syngnathids to postpone suction generation until the end of cranial rotation, a fundamental difference from non-syngnathiform fishes.
Why Ionic Amphiphilic “Block” Copolymer Can Be Non-surface Active? Comparison of Homopolymer, Block and Random Copolymers of Poly(styrenesulfonate)
Authors: Matsuoka Hideki , Hachisuka Masahiro , Uda Kyohei , Onishi Tomoyuki , Ozoe Shinji 
Published: October 2012

Abstract
Ionic amphiphilic diblock copolymers, such as polystyrene-b-poly(styrenesulfonate), show non-surface activity when some requirements are satisfied. The main origin of this unique property has been thought to be an image charge repulsion at the air/water interface. In this study, surface activity/non-activity was examined for random copolymers in addition to homopolymers. Random copolymers of styrene and styrenesulfonate were found to be surface active, while the poly(styrenesulfonate) homopolymer was slightly surface active. This observation cannot be interpreted by image charge repulsion alone since these are all polyanions and the block copolymer is mostly hydrophobic. Stable polymer micelle formation in the block copolymer system is also an essential origin of non-surface activity.