bluuebunny/crossref_metadata_2025 huggingface dataset:
Vaccination and mucosal responses to Helicobacter pylori infection.
Authors: Lee A , Buck F
Published: May 2014

H. pylori infection persists for life if not treated, and is responsible for major morbidity and mortality throughout the world. Preventative immunization, once thought to be impossible, is now considered by many to be the only practical approach to large‐scale elimination of the bacterium from susceptible populations. High rates of protection have been achieved in the H. felis mouse model, utilizing antigens ranging from whole cells to purified recombinant proteins selected on the basis of their role in pathogenicity. Immunization has also been shown to cure established infection. H. pylori mouse models have been developed and may become the model of choice. Urease remains the favourite antigen but combinations will most likely be required. A priority is to define alternate muscosal adjuvants, as some used in the animal models may be too toxic for use in humans. Also, there is a need to understand the basis of immunization. Why does the natural immune response to H. pylori fail while the artificially stimulated response succeeds? The first important steps towards a vaccine have been made but, given safety issues and regulatory requirements, it may be 5‐8 years before the final product becomes available. Over these years antimicrobial resistance is likely to be an increasing problem in the treatment of H. pylori infections. Thus, when the vaccine comes, the time will be ripe for the completely new approach of therapeutic immunization.
Flexible design of wide‐pipeline‐based WiMAX QC‐LDPC decoder architectures on FPGAs using high‐level synthesis
Authors: Andrade J. , Falcao G. , Silva V.
Published: May 2014

A novel wide‐pipeline low‐density parity‐check (LDPC) decoder approach for the worldwide interoperability for microwave access (WiMAX) standard (802.16e) is proposed for execution on field‐programmable gate arrays (FPGAs), using a high‐level synthesis tool to reduce the development effort and design validation time that generates a wide‐pipeline architecture. Optimised open computing language (OpenCL)‐based kernels are developed and the integration of distinct configurations of single instruction multiple data and compute units to increase the level of parallelism are analysed. The decoding throughput surpasses the minimal requirements of 75 Mbit/s, a key figure of merit that ranks the design with other very large‐scale integration‐based approaches. Furthermore, extra precision is deployed with 8‐bit fixed‐point arithmetic, delivering superior bit error rate performance and lower error floor regions.
Grip force measurement of forceps with fibre Bragg grating sensors
Authors: Lim Soo‐Chul , Lee Hyung‐Kew , Park Joonah
Published: May 2014

Although haptic feedback is critical for many surgical tasks, surgeons cannot currently obtain haptic feedback from teleoperated surgical robots because it is difficult to attach force sensitive sensors to the surgical robot in the surgery environment. Therefore, force sensitive forceps with an optical fibre Bragg grating sensor attached on the grasper are proposed. The proposed prototype forceps confirmed that the sensitive grasping force in the teleoperated grasper is comparable to the providing force and measuring force.
1–5 GHz duty‐cycle corrector circuit with wide correction range and high precision
Authors: Qiu Yusong , Zeng Yun , Zhang Feng
Published: May 2014

An all‐analogue feedback duty‐cycle corrector (DCC) circuit with high precision and frequency is presented to tighten duty cycle into an allowable range and compensate for duty‐cycle uncertainties in high‐speed interfaces. The proposed DCC is employed to calibrate the duty cycle of the clock to reduce the deterministic jitter introduced by the duty‐cycle distortion. It extracts the duty‐cycle information by a differential duty amplifier detection scheme and corrects the clock distortion by a duty‐cycle adjuster through the negative feedback loop. The DCC has improved robustness, correction range and operating frequency as compared with other DCCs. With post‐simulated results using 55 nm CMOS technology, the output duty cycle is corrected to 50 ± 0.1% over the input duty‐cycle range of 20–80% for 1–5 GHz. It consumes 3.6 mW at 3 GHz using a 1.2 V supply voltage and occupies an area of only 0.00174 mm2.
Temperature gradient sensor from pulsed power supply duty cycle in ultra‐low‐power energy harvesting system
Authors: Jove‐Casulleras R. , Ramos J. , Ccorimanya H. , Camps A. , Alarcon E. , Amezaga A. , Bou E.
Published: May 2014

Directly interfacing sensors that link sensors to micro‐controllers without a signal conditioning circuit or an analogue‐to‐digital converter on the one side and energy harvesting systems on the other side are two key enabling technologies to create self‐powered autonomous low‐cost and low‐maintenance sensor networks. In this reported work, both technologies are concurrently combined in such a way that the duty cycle of the pulsed power supply provided by the harvesting system itself yields in turn a temperature gradient sensor functionality. Originally conceived to power a low‐power satellite beacon in a CubeSat project, it has found application, among other applications, in automatic air conditioning and heating systems aiming smart buildings.
Spiral symmetry centroid detection
Authors: Wang Jiandong , Feng Wei , Sun Jizhou
Published: May 2014

Radial symmetry detection is a hot topic in computer vision owing to its importance in understanding the image structure and content. A major generalisation to the problem is presented and single image spiral symmetric centroid detection is studied. Since radial symmetry is just a particular case in the model of spiral symmetry, spiral symmetry detection is more challenging and general. For this new problem, a fast and effective voting‐based solution is proposed, which can reliably detect both the classical radial symmetric centre and the more general spiral symmetric centroid. Extensive experiments validate the generality and practicability of the proposed approach.
Wideband MIMO antenna with enhanced isolation for LTE, WiMAX and WLAN mobile handsets
Authors: Toktas A. , Akdagli A.
Published: May 2014

A novel and compact wideband multiple input multiple output (MIMO) antenna for mobile terminals is presented. The proposed antenna operates over a wide frequency range of 1.79–3.77 GHz suitable for long‐term evolution (LTE), worldwide interoperability for microwave access (WiMAX) and wireless local area network (WLAN) handheld devices. The MIMO antenna structure consists of two identical radiators with a small size of 10 × 17.7 mm2 and a parasitic element with a T‐shape. The radiators, which comprise four branches with a meandered strip feed, are symmetrically located with respect to the T‐shaped parasitic element. The parasitic element is a novel design appended at the ground plane. By using this parasitic element, a better isolation performance has been achieved between the two radiators. The overall performance of the antenna in terms of s‐parameters, radiation pattern, gain and envelope correlation coefficient is investigated and verified through measurements. The results obtained show that the proposed antenna has attractive physical properties due to being small, compact and embeddable in mobile handsets, and has good characteristics of wideband, isolation, gain and radiation pattern.
Analytical appraisal of importance of different fitting parameters in device compact models
Authors: Camps O. , Picos R. , Roca M. , Isern E. , Font J. , Cerdeira A. , Estrada M. , Garcia‐Moreno E.
Published: May 2014

The main objective of compact device modelling is to perform the best possible fitting of the model to the measured characteristics. To do so, there are some parameters in the models that must be adjusted to the actual values used in the technology, plus some other parameters that are used to overcome some of the limitations of the assumptions used in the model development. Obtaining the first set is usually straightforward, whereas determining the second set is more difficult, because the extraction methods are not always efficient and, moreover, there are parameters that are correlated with others, complicating the whole issue. Moreover, there may be parameters that are not relevant for the specific technology. If one could be able to determine the importance of different parameters, then effort could be better directed by dedicating more effort to the most important parameters. A method to order a list of given model parameters using the calculated importance as the criterion is proposed. This importance is calculated using a modification of the Google PageRank algorithm.
Is Hamming distance only way for matching binary image feature descriptors?
Authors: Bostanci E.
Published: May 2014

Brute force matching of binary image feature descriptors is conventionally performed using the Hamming distance. The use of alternative metrics is assessed in order to see whether they can produce feature correspondences that yield more accurate homography matrices. Two statistical tests, namely analysis of variance (ANOVA) and McNemar's test were employed for the evaluation. Results show that Jackard‐Needham and Dice metrics can display better performance for some descriptors. Yet, these performance differences were not found to be statistically significant.
Multi‐modal image registration using edge neighbourhood descriptor
Authors: Cao Zhulou , Dong Enqing
Published: May 2014

Multi‐modal medical image registration remains a challenging and active area of research owing to the difficulty of dealing with intensity distortions. Local patch‐based entropy images were recently proposed to address this problem. However, this method suffers from the complexity of calculation of the entropy. Proposed is a new dense descriptor for an image, named the edge neighbourhood descriptor, which assigns different values to different image regions, namely the image background, image edges, edge neighbourhoods and the remaining area. The edge neighbourhood descriptor is faster than the entropy image. Experimental results show that this new descriptor can improve registration accuracy compared with the results of the entropy image and the mutual information method.
UHF band switchable superconducting filter with pin diode switches
Authors: Song Xiaoke , Wei Bin , Cao Bisong , Guo Xubo , Zhang Xiaoping
Published: May 2014

A low‐loss switchable superconducting filter is presented. High Q resonators loaded with switchable superconducting interdigital capacitors are introduced. A two‐pole 2‐bit switchable high‐temperature superconducting (HTS) filter at 516 MHz with a bandwidth of 29 MHz is designed and fabricated. The measured centre frequency tuning range is 33 MHz (6.4%). In all states, the HTS filter with pin diode switches exhibits an insertion loss <0.81 dB and a good return loss better than 16.8 dB.
Subthreshold DC‐gain enhancement by exploiting small size effects of MOSFETs
Authors: Yang Minhao , Liu Shih‐Chii , Delbruck Tobi
Published: May 2014

A pseudo‐cascode split‐transistor technique is proposed for DC‐gain enhancement of amplifiers in the subthreshold by exploiting the small size effects of metal–oxide semiconductor field effect transistors (MOSFETs) including the reverse short‐channel effect and the inverse narrow‐width effect. It requires no body‐biasing and occupies a small area. A compact 114 μm2 two‐stage amplifier with pseudo‐cascode compensation for in‐pixel amplification in vision sensors has been designed using the proposed technique. A total of 10 samples of split‐transistors and amplifiers fabricated in an UMC 0.18 μm standard CMOS process were measured. More than half of the tested split‐transistors show considerable DC‐gain enhancement over a wide range of bias currents and nine amplifiers have increased DC gains larger than 85 dB at about 4 nA power consumption.
Security‐oriented cooperation scheme in wireless cooperative networks
Authors: Wang Li , Yang Lie‐Liang , Ma Jacob Xin , Song Mei
Published: May 2014

This study proposes a security‐oriented cooperation (SOC) scheme, which first determines one of the three possible cooperation scenarios, namely the jammer only, relay only and the relay–jammer pair, according to the security requirement and network's operational conditions. After determining a cooperation scenario, then, the selection of a relay or/and a jammer as well as their transmit power are jointly optimised with the objective to attain a good trade‐off between security performance and energy consumption. The performance of the networks employing the proposed SOC is investigated here over finite‐state Markov channels. The studies and results explain that the proposed SOC scheme constitutes one of the promising SOC schemes. It belongs to a generalised cooperative security scheme, which adapts according to the specific security requirement and communication environments.
Radio‐frequency fingerprinting for mitigating primary user emulation attack in low‐end cognitive radios
Authors: Rehman Saeed Ur , Sowerby Kevin W. , Coghill Colin
Published: May 2014

Recently, radio‐frequency (RF) fingerprinting has been proposed for mitigating primary user emulation (PUE) attacks in cognitive radio networks (CRNs). The widespread practical implementation of cognitive radio (CR) is likely to utilise software‐defined radios with a low‐end (i.e. low‐cost) receiver built with inexpensive analogue components. This study experimentally analyses the feasibility of RF fingerprinting for mitigating PUE attacks using low‐end software‐defined CRs. Seven universal software radio peripherals are used as low‐end CR receivers and their resulting performance is analysed for ad hoc and infrastructure CRN scenarios. The performance analysis is performed for the largest known data set of its kind, which consists of 490 000 measurements from seven identical transmitters across eight receivers. It is found that impairments in the front‐end of a low‐end receiver affects the accuracy of transmitter classification and this accuracy varies across receivers. The results suggest that RF fingerprinting can be effectively used for mitigating PUE attacks in an ad hoc CRN at high receiver signal‐to‐noise ratio whereas RF fingerprinting is not a practical solution for mitigating PUE attacks in an infrastructure CRN.
Adaptive multiobjective optimisation for energy efficient interference coordination in multicell networks
Authors: Fei Zesong , Xing Chengwen , Li Na , Kuang Jingming
Published: May 2014

In this paper, the authors investigate the distributed power allocation for the multicell orthogonal frequency division multiple access networks by taking both the energy efficiency and the intercell interference (ICI) mitigation into account. A performance metric termed as throughput contribution is exploited to measure how the ICI is effectively coordinated. To achieve a distributed power allocation scheme for each base station (BS), the throughput contribution of each BS to the network is first given based on a pricing mechanism. Different from the existing works, a biobjective problem is formulated based on the multiobjective optimisation theory, which aims at maximising the throughput contribution of the BS to the network and minimising its total power consumption at the same time. By using the method of the Pascoletti and Serafini scalarisation, the relationship between the varying parameters and the minimal solutions is revealed. Furthermore, to exploit the relationship an algorithm is proposed based on which all the solutions on the boundary of the efficient set can be achieved by adaptively adjusting the involved parameters. With the obtained solution set, the decision maker has more choices in the power allocation schemes in terms of both the energy consumption and the throughput. Finally, the performance of the algorithm is assessed by the simulation results.
Near‐optimum detection scheme with relay selection technique for asynchronous cooperative relay networks
Authors: Qaja Walid Mohamed , Elazreg Abdulghani M. , Chambers Jonathon A.
Published: May 2014

A new near‐optimum detection scheme for asynchronous wireless relay networks is proposed to cancel the interference component at the destination node caused by timing misalignment from the relay nodes. The detection complexity at the destination node as compared with a previous sub‐optimum detection scheme is reduced. Closed‐loop extended orthogonal space time block coding and outer convolutive coding are utilised to maximise end‐to‐end performance. A relay selection technique is also proposed in this study for two dual‐antenna relay nodes to enhance the system performance by selecting the best links and the smallest time delay error among the relay nodes. Simulation results confirm that the proposed near‐optimum detection scheme with relay selection is very effective at removing intersymbol interference at the destination node and achieving full cooperative diversity with unity data transmission rate between the relay nodes and the destination node.
Robust transcale decentralised estimation fusion for multisensor systems based on wavelet packet decomposition
Authors: Zhao Lin , Jia Yingmin , Xie Yongchun
Published: May 2014

In this study, an effective wavelet packet decomposition (WPD)‐based robust transcale decentralised estimation fusion algorithm is proposed for multisensor systems. The standard state‐space models of wavelet packet coefficients at the coarsest scale decomposition layer are established by Haar WPD. Based on the above models, the decentralised H∞ filtering fusion formulae is employed to obtain the fusion estimates at the coarsest scale decomposition layer, and these estimates are then used to reconstruct the estimates at the finest scale by an inverse WPD transform. At last, the feasibility analysis of the proposed algorithm is given. Two simulation examples are presented to illustrate the effectiveness of the proposed algorithm.
Integrated fault‐tolerant control methodology for non‐linear dynamical networked control systems subject to time‐varying delay
Authors: Wu Wei , Fang Huajing
Published: May 2014

This study deals with the problem of designing an integrated fault‐tolerant control (FTC) methodology for non‐linear dynamical networked control systems subject to time‐varying delay. For the convenience of residual generation, influence caused by network‐induced delay is transformed into time‐varying uncertainty, which facilitates further manipulation. A fault diagnosis scheme is utilised for fault detection and isolation. On the basis of the uncertainty and fault information obtained by the fault diagnosis procedure, an FTC component is developed to compensate for the effects of uncertainty and fault. In the absence of fault, a nominal controller is employed to deal with the system uncertainty. After fault detection estimator is activated, the controller is reconfigured to guarantee the boundedness of all the system signals until the fault is isolated. After the fault is isolated, the controller is reconfigured to improve the control performance by using the fault information generated by the isolation module. In addition, the stability of the proposed scheme is rigorously investigated. Finally, a simulation example is utilised to illustrate the performance of the proposed scheme.
Tracking with scattering descriptor
Authors: Tian Xiaolin , Jiao Licheng , Shang Xiaowei
Published: May 2014

This study proposes a new method to track the moving object based on undecimated scattering transform (UST). The UST removes the down‐sampling operation from the traditional scattering transform to produce a complete representation. Based on the UST, the structural information of object can be captured, which is a highly discriminative representation and facilitates the tracker to distinguish the object from background. The update parameter of tracking model is adaptively adjusted by the correlation coefficient. Occlusion identification is achieved by using a new cascaded model, which can correctly find occlusion and avoid the drift. Experimental results demonstrate that the proposed method is able to track the object accurately and reliably in realistic videos where the appearance and motion change drastically over time.
New algorithm for detecting power transformer faults based on M‐robust estimation of sound signals
Authors: Đukić Goran , Čukarić Aleksandar
Published: May 2014

M‐robust algorithm for detecting power transformer inner faults accompanied by an electrical arc based on sound signal processing is presented. The electrical arc, which exists during the fault, generates specific sound waves. The efficiency of the presented algorithm for processing these types of sound signals is confirmed by performing experimental tests. It has been shown that even in the presence of different types of disturbances (including impulse disturbance), the M‐robust methodology gives fast and reliable results which lead to the detection of transformer inner fault with electrical arc. The presented algorithm efficiently and quickly detects the unwanted processes in the transformer which do not result in a current increase (the initial discharge which precedes the electrical arc) and which could not be detected by the standard protection functions. The presented methodology gives an opportunity for further development and online implementation of a simple, low cost and broadly applicable system for the detection of internal faults in transformers, independently of the voltage and power level.
Multi‐area optimal power flow with changeable transmission topology
Authors: Liu Cong , Wang Jianhui , Fu Yong , Koritarov Vladimir
Published: May 2014

This study presents a framework for coordinating multi‐area optimal power flow with adjustable network topology in an electric power system. The modelling is accomplished in a coordinated but not a centralised fashion. Each regional operator dispatches its own generation and switches its own transmission network to reach its optimal benefits. The proposed model uses augmented Lagrangian relaxation to realise decomposition. No other information is exchanged between the regional operators except the Lagrangian multipliers. This study compares the centralised transmission switching model and the proposed decentralised method by using several numerical tests. The results verify the effectiveness of the solution methodology. The decomposition framework proposed in this study can serve as a foundation for implementing parallel computing.
Nanocrystals inside : fabrication de composants mémoires MOS à base de nanocristaux de silicium
Authors: Grisolia J. , Ben Assayag G. , Diaz R. , Duprat Ch. , Guerin F. , Capello C. , Rouabhi C. , Gessinn F. , Respaud M.
Published: May 2014

Cet article présente une formation de courte durée, en salle blanche, donnant une approche
pratique complète du concept « NANO-INSIDE » appliqué à la réalisation de mémoire de type FLASH
par l’intégration de nanocristaux de silicium dans la technologie NMOS. Il aborde toutes les
opérations de fabrication des circuits intégrés de type « mémoires », ainsi que leurs caractérisations à
la fois matériaux et composants (électriques). In fine, le but est de montrer à un public étudiant
comment une information peut être mémorisée avec des objets nanométriques de façon durable et
conservée même sans alimentation.
Modeling charge transport in C60-based self-assembled monolayers for applications in field-effect transistors
Authors: Leitherer S. , Jäger C. M. , Halik M. , Clark T. , Thoss M.
Published: May 2014

We have investigated the conductance properties of C60-containing self-assembled monolayers (SAMs), which are used in organic field-effect transistors, employing a combination of molecular-dynamics simulations, semiempirical electronic structure calculations, and Landauer transport theory. The results reveal the close relation between the transport characteristics and the structural and electronic properties of the SAM. Furthermore, both local pathways of charge transport in the SAMs and the influence of structural fluctuations are analyzed.
Suppression of vertical instability in elongated current-carrying plasmas by applying stellarator rotational transform
Authors: ArchMiller M. C. , Cianciosa M. R. , Ennis D. A. , Hanson J. D. , Hartwell G. J. , Hebert J. D. , Herfindal J. L. , Knowlton S. F. , Ma X. , Maurer D. A. , Pandya M. D. , Traverso P.
Published: May 2014

The passive stability of vertically elongated current-carrying toroidal plasmas has been investigated in the Compact Toroidal Hybrid, a stellarator/tokamak hybrid device. In this experiment, the fractional transform f, defined as the ratio of the imposed external rotational transform from stellarator coils to the total rotational transform, was varied from 0.04 to 0.50, and the elongation κ was varied from 1.4 to 2.2. Plasmas that were vertically unstable were evidenced by motion of the plasma in the vertical direction. Vertical drifts are measured with a set of poloidal field pickup coils. A three chord horizontally viewing interferometer and a soft X-ray diode array confirmed the drifts. Plasmas with low fractional transform and high elongation are the most susceptible to vertical instability, consistent with analytic predictions that the vertical mode in elongated plasmas can be stabilized by the poloidal field of a relatively weak stellarator equilibrium.
Composition determination of quaternary GaAsPN layers from single X-ray diffraction measurement of quasi-forbidden (002) reflection
Authors: Tilli J.-M. , Jussila H. , Yu K. M. , Huhtio T. , Sopanen M.
Published: May 2014

GaAsPN layers with a thickness of 30 nm were grown on GaP substrates with metalorganic vapor phase epitaxy to study the feasibility of a single X-ray diffraction (XRD) measurement for full composition determination of quaternary layer material. The method is based on the peak intensity of a quasi-forbidden (002) reflection, which is shown to vary with changing arsenic content for GaAsPN. The method works for thin films with a wide range of arsenic contents and shows a clear variation in the reflection intensity as a function of changing layer composition. The obtained thicknesses and compositions of the grown layers are compared with accurate reference values obtained by Rutherford backscattering spectroscopy combined with nuclear reaction analysis measurements. Based on the comparison, the error in the XRD defined material composition becomes larger with increasing nitrogen content and layer thickness. This suggests that the dominating error source is the deteriorated crystal quality due to the nonsubstitutional incorporation of nitrogen into the crystal lattice and strain relaxation. The results reveal that the method overestimates the arsenic and nitrogen content within error margins of about 0.12 and about 0.025, respectively.
Intestinal cell kinase, a protein associated with endocrine-cerebro-osteodysplasia syndrome, is a key regulator of cilia length and Hedgehog signaling
Authors: Moon Heejung , Song Jieun , Shin Jeong-Oh , Lee Hankyu , Kim Hong-Kyung , Eggenschwiller Jonathan T. , Bok Jinwoong , Ko Hyuk Wan
Published: May 2014

Significance

Endocrine-cerebro-osteodysplasia (ECO) syndrome, a human genetic disorder affecting multiple organs, is caused by a mutation in
intestinal cell kinase
(
Ick
) gene. In algae and invertebrates,
ICK
homologs are known to be associated with ciliary formation. However, it is unclear whether this role of ICK is conserved in mammals and whether clinical symptoms of ECO syndrome are caused by ciliary defects. In this study, using in vivo and in vitro approaches, we found that abnormal ICK function indeed resulted in defective cilia, leading to abnormal Hedgehog signaling. Our results suggest that the role of ICK in ciliogenesis may be highly conserved throughout evolution and that ECO syndrome may be categorized as a ciliopathy, an increasingly recognized class of human genetic disorders.
Structural and functional analysis of the human spliceosomal DEAD-box helicase Prp28
Authors: Möhlmann Sina , Mathew Rebecca , Neumann Piotr , Schmitt Andreas , Lührmann Reinhard , Ficner Ralf
Published: May 2014

The DEAD-box protein Prp28 is essential for pre-mRNA splicing as it plays a key role in the formation of an active spliceosome. Prp28 participates in the release of the U1 snRNP from the 5′-splice site during association of the U5·U4/U6 tri-snRNP, which is a crucial step in the transition from a pre-catalytic spliceosome to an activated spliceosome. Here, it is demonstrated that the purified helicase domain of human Prp28 (hPrp28ΔN) binds ADP, whereas binding of ATP and ATPase activity could not be detected. ATP binding could not be observed for purified full-length hPrp28 either, but within an assembled spliceosomal complex hPrp28 gains ATP-binding activity. In order to understand the structural basis for the ATP-binding deficiency of isolated hPrp28, the crystal structure of hPrp28ΔN was determined at 2.0 Å resolution. In the crystal the helicase domain adopts a wide-open conformation, as the two RecA-like domains are extraordinarily displaced from the productive ATPase conformation. Binding of ATP is hindered by a closed conformation of the P-loop, which occupies the space required for the γ-phosphate of ATP.
Structural basis for glucose tolerance in GH1 β-glucosidases
Authors: de Giuseppe Priscila Oliveira , Souza Tatiana de Arruda Campos Brasil , Souza Flavio Henrique Moreira , Zanphorlin Leticia Maria , Machado Carla Botelho , Ward Richard John , Jorge Joao Atilio , Furriel Rosa dos Prazeres Melo , Murakami Mario Tyago
Published: May 2014

Product inhibition of β-glucosidases (BGs) by glucose is considered to be a limiting step in enzymatic technologies for plant-biomass saccharification. Remarkably, some β-glucosidases belonging to the GH1 family exhibit unusual properties, being tolerant to, or even stimulated by, high glucose concentrations. However, the structural basis for the glucose tolerance and stimulation of BGs is still elusive. To address this issue, the first crystal structure of a fungal β-glucosidase stimulated by glucose was solved in native and glucose-complexed forms, revealing that the shape and electrostatic properties of the entrance to the active site, including the +2 subsite, determine glucose tolerance. The aromatic Trp168 and the aliphatic Leu173 are conserved in glucose-tolerant GH1 enzymes and contribute to relieving enzyme inhibition by imposing constraints at the +2 subsite that limit the access of glucose to the −1 subsite. The GH1 family β-glucosidases are tenfold to 1000-fold more glucose tolerant than GH3 BGs, and comparative structural analysis shows a clear correlation between active-site accessibility and glucose tolerance. The active site of GH1 BGs is located in a deep and narrow cavity, which is in contrast to the shallow pocket in the GH3 family BGs. These findings shed light on the molecular basis for glucose tolerance and indicate that GH1 BGs are more suitable than GH3 BGs for biotechnological applications involving plant cell-wall saccharification.
Methyl (E)-3-(2-formylphenoxy)acrylate
Authors: Karthikeyan S. , Sethusankar K. , Selvakumar R. , Bakthadoss M.
Published: May 2014

In the title compound, C11H10O4, the methyl acrylate substituent adopts an extendedEconformation with all torsion angles close to 180°. The conformation of the keto group with respect to the olefinic double bond is typicallyS-trans. In the crystal, molecules are linkedviapairs of C—H...O hydrogen bonds, forming inversion dimers with anR22(8) graph-set motif. The dimers are further linkedviaC—H...O hydrogen bonds, forming chains along [001], which encloseR32(16) graph-set ring motifs. The keto group O atomaccepts two C—H...O interactions.
1-(2-Bromo-4-chlorophenyl)-3,3-dimethylthiourea
Authors: El-Hiti Gamal A. , Smith Keith , Hegazy Amany S. , Alotaibi Mohammad Hayal , Kariuki Benson M.
Published: May 2014

In the title compound, C9H10BrClN2S, the dimethylthiourea group is twisted from the benzene ring plane by 54.38 (6)°. In the crystal, the amino groups are involved in the formation of N—H...S hydrogen bonds, which link the molecules into chains along [010]. Weak C—H...Cl interactions further link these chains into layers parallel to theabplane.
5-Cyano-1,3-phenylene diacetate
Authors: Abbassi Bahar , Brumfield Michela , Jones Lloyd M. , Nesterov Vladimir N. , Carr Andrew J.
Published: May 2014

In the title molecule, C11H9NO4, the two acetoxy groups are twisted from the plane of the benzene ring by 67.89 (4) and 53.30 (5)°. Both carbonyl groups are on the same side of the aromatic ring. In the crystal, weak C—H...O hydrogen bonds link molecules into layers parallel to theacplane. The crystal packing exhibits π–π interactions between the aromatic rings, indicated by a short intercentroid distance of 3.767 (3) Å.
4-(Pyrimidin-2-yl)piperazin-1-ium (E)-3-carboxyprop-2-enoate
Authors: Yamuna Thammarse S. , Kaur Manpreet , Jasinski Jerry P. , Yathirajan H. S.
Published: May 2014

In the cation of the title salt, C8H13N4+·C4H3O4−, the piperazinium ring adopts a slightly distorteded chair conformation. In the crystal, a single strong O—H...O intermolecular hydrogen bond links the anions, forming chains along thec-axis direction. The chains of anions are linked by the cations,viaN—H...O hydrogen bonds, forming sheets parallel to (100). These layers are linked by weak C—H...O hydrogen bonds, forming a three-dimensional structure. In addition, there are weak π–π interactions [centroid–centroid distance = 3.820 (9) Å] present involving inversion-related pyrimidine rings.
1,8-Diazabicyclo[5.4.0]undec-7-en-8-ium bromido(phthalocyaninato)zincate
Authors: Przybył Bartosz , Janczak Jan
Published: May 2014

The title compound, (C9H17N2)[ZnBr(C32H16N8)], contains a bromido(phthalocyaninato)zincate anion and a protonated 1,8-diazabicyclo[5.4.0]undece-7-ene cation, [DBUH]+. The central ZnIIatom has a distorted square-pyramidal geometry, with four isoindole N atoms of the macrocycle in equatorial positions and a bromide ion in the axial position. The latter has a relatively high displacement parameter, but no evidence for disorder was obtained. The central ZnIIatom is displaced by 0.488 (3) Å from the mean plane defined by the four isoindole N atoms. The [DBUH]+cation is involved in an almost linear N—H...Br hydrogen bond. In the crystal, π–π interactions lead to a relatively short distance of 3.366 (3) Å between the phthalocyaninate rings.
Understanding the structure details when drying hydrate crystals of pharmaceuticals – interpretations from diffuse scattering and inter-modulation satellites of a partially dehydrated crystal
Authors: Chan E. J. , Gao Q. , Dabros M.
Published: May 2014

Simplified models for the crystal lattice of the sesquihydrate form of the hemi-sulfate salt of (5S,6S,9R)-5-amino-6-(2,3-difluorophenyl)-6,7,8,9-tetrahydro-5H-cyclohepta[b]pyridin-9-yl 4-(2-oxo-2,3-dihydro-1H-imidazol[4,5b]pyridin-1-yl)-1-piperidine carboxylate (BMS-927711, C28H29F2N6O3+) are used to calculate diffuse diffraction features in order to develop a mechanistic understanding of the dehydration process with respect to disruption of the lattice, since a Bragg model cannot be established. The model demonstrates that what we observe when the water leaves the crystal is partial transformation from the parent form to a child form (a new form, less hydrated and structurally related to the parent). Yet this `dried' structure is not a pure phase. It consists of semi-random layers of both child, parent and an interfacial layer which has a modulated structure that represents a transitory phase. Understanding the fact that a single `dried' crystal can have the disordered layer structure described as well as understanding mechanistic relationships between the phases involved can have implications in understanding the effect of common large scale bulk drying procedures. During the development of BMS-927711, difficulties did arise during characterization of the dried bulk when using only routine solid-state analysis. The material is now better understood from this diffraction study. The diffraction experiments also reveal intermodulation satellites, which upon interpretation yield even more structural information about the crystal transformation. The model suggests the mechanism of transformation is laminar in which layers of the crystal are driven to approach a stableB-centered supercell phase of lower water content.
Crystallographic studies of gas sorption in metal–organic frameworks
Authors: Carrington Elliot J. , Vitórica-Yrezábal Iñigo J. , Brammer Lee
Published: May 2014

Metal–organic frameworks (MOFs) are a class of porous crystalline materials of modular design. One of the primary applications of these materials is in the adsorption and separation of gases, with potential benefits to the energy, transport and medical sectors.In situcrystallography of MOFs under gas atmospheres has enabled the behaviour of the frameworks under gas loading to be investigated and has established the precise location of adsorbed gas molecules in a significant number of MOFs. This article reviews progress in such crystallographic studies, which has taken place over the past decade, but has its origins in earlier studies of zeolites, clathratesetc. The review considers studies by single-crystal or powder diffraction using either X-rays or neutrons. Features of MOFs that strongly affect gas sorption behaviour are discussed in the context ofin situcrystallographic studies, specifically framework flexibility, and the presence of (organic) functional groups and unsaturated (open) metal sites within pores that can form specific interactions with gas molecules.
High-pressure study of binary thorium compounds from first principles theory and comparisons with experiment
Authors: Kanchana V. , Vaitheeswaran G. , Svane A. , Heathman S. , Gerward L. , Staun Olsen J.
Published: May 2014

The high-pressure structural behaviour of a series of binary thorium compounds ThX(X= C, N, P, As, Sb, Bi, S, Se, Te) is studied using the all-electron full potential linear muffin-tin orbital (FP-LMTO) method within the generalized gradient approximation (GGA) for the exchange and correlation potential. The calculated equlibrium lattice parameters and bulk moduli, as well as the equations of state agree well with experimental results. New experiments are reported for ThBi and ThN. Calculations are performed for the ThXcompounds in the NaCl- and CsCl-type crystal structures, and structural phase transitions from NaCl to CsCl are found in ThP, ThAs, ThSb and ThSe at pressures of 26.1, 22.1, 8.1 and 23.2 GPa, respectively, in excellent agreement with experimental results. ThC, ThN and ThS are found to be stable in the NaCl structure, and ThBi and ThTe in the CsCl structure, for pressures below 50 GPa. The electronic structures of the ThXcompounds are studied using the quasiparticle self-consistentGWmethod (G: Green function,W: dynamically screened interaction).
Crystallization and preliminary X-ray crystallographic studies of dehydroascorbate reductase (DHAR) fromOryza sativaL.japonica
Authors: Do Hackwon , Kim Il-Sup , Kim Young-Saeng , Shin Sun-Young , Kim Jin-Ju , Mok Ji-Eun , Park Seong-Im , Wi Ah Ram , Park Hyun , Kim Han-Woo , Yoon Ho-Sung , Lee Jun Hyuck
Published: May 2014

Dehydroascorbate reductase fromOryza sativaL.japonica(OsDHAR), a key enzyme in the regeneration of vitamin C, maintains reduced pools of ascorbic acid to detoxify reactive oxygen species. In previous studies, the overexpression of OsDHAR in transgenic rice increased grain yield and biomass as well as the amount of ascorbate, suggesting that ascorbate levels are directly associated with crop production in rice. Hence, it has been speculated that the increased level of antioxidants generated by OsDHAR protects rice from oxidative damage and increases the yield of rice grains. However, the crystal structure and detailed mechanisms of this important enzyme need to be further elucidated. In this study, recombinant OsDHAR protein was purified and crystallized using the sitting-drop vapour-diffusion method at pH 8.0 and 298 K. Plate-shaped crystals were obtained using 0.15 Mpotassium bromide, 30%(w/v) PEG MME 2000 as a precipitant, and the crystals diffracted to a resolution of 1.9 Å on beamline 5C at the Pohang Accelerator Laboratory. The X-ray diffraction data indicated that the crystal contained one OsDHAR molecule in the asymmetric unit and belonged to space groupP21with unit-cell parametersa= 47.03,b= 48.38,c= 51.83 Å, β = 107.41°.
Structure of transportin SR2, a karyopherin involved in human disease, in complex with Ran
Authors: Tsirkone Vicky G. , Beutels Katrien G. , Demeulemeester Jonas , Debyser Zeger , Christ Frauke , Strelkov Sergei V.
Published: May 2014

Transportin SR2 (TRN-SR2) is a β-type karyopherin responsible for the nuclear import of specific cargoes, including serine/arginine-rich splicing factors. The protein has been implicated in a variety of human diseases, including HIV infection, primary biliary cirrhosis and limb-girdle muscular dystrophy 1F. Towards understanding its molecular mechanism, a 2.9 Å resolution crystal structure of human TRN-SR2 complexed with the small GTPase Ran has been determined. TRN-SR2 is composed of 20 α-helical HEAT repeats forming a solenoid-like fold. The first nine repeats form a `cradle' for the binding of RanGTP, revealing similarities but also differences with respect to the related importin 13 complex.
Anatomical and scanning electron microscopic characteristics of the oropharyngeal cavity (tongue, palate and laryngeal entrance) in the southern lapwing (Charadriidae: Vanellus chilensis, Molina 1782)
Authors: Erdoğan Serkan , Pérez William
Published: May 2014

This investigation aimed to determine the morphological characteristics of the tongue, palate and laryngeal entrance of southern lapwing by gross anatomy and scanning electron microscopy. For this purpose, the organs of three birds were used as material. Numerous densely distributed acicular projections were found on the lingual apex. Papillary crest consisting of sharp conical papillae were observed between the body and root of the tongue. Conical papillae of the lateral border of the papillary crest were triangular in form, and other conical papillae of the papillary crest were shorter in form. There were no papillary projections or papillae on the smooth surfaces of the lingual body and radix. On the median part of the palate, larger conical papillae, which were directed caudally, also surrounded entrance of the choanal cleft. The transversal papillary rows of conical papillae were observed between the rostral and caudal parts of the choanal cleft and on the caudal border of the infundibular cleft. The laryngeal entrance was surrounded by smooth mucosa without conical papillae. However, in the caudal border of the glottic fissure, there was a conical papillary row formed by numerous conical papillae. There were no anatomical differences between female and male birds.
Fatigue, psychological and cognitive impairment following transient ischaemic attack and minor stroke: a systematic review
Authors: Moran G. M. , Fletcher B. , Feltham M. G. , Calvert M. , Sackley C. , Marshall T.
Published: May 2014

Transient ischaemic attack (TIA) and minor stroke are characterized by short‐lasting symptoms; however, anecdotal and empirical evidence suggests that these patients experience ongoing cognitive/psychological impairment for which they are not routinely treated. The aims were (i) to investigate the prevalence and time course of fatigue, anxiety, depression, post‐traumatic stress disorder(PTSD) and cognitive impairment following TIA/minor stroke; (ii) to explore the impact on quality of life (QoL), change in emotions and return to work; and (iii) to identify where further research is required and potentially inform an intervention study. A systematic review of MEDLINE, EMBASE, PSYCINFO, CINAHL, the Cochrane libraries and the grey literature between January 1993 and April 2013 was undertaken. Literature was screened and data were extracted by two independent reviewers. Studies were included of adult TIA/minor stroke participants with any of the outcomes of interest: fatigue, anxiety, depression, PTSD, cognitive impairment, QoL, change in emotions and return to work. Random‐effects meta‐analysis pooled outcomes by measurement tool. Searches identified 5976 records, 289 were assessed for eligibility and 31 studies were included. Results suggest high levels of cognitive impairment and depression post‐TIA/minor stroke which decreased over time. However, frequencies varied between studies. Limited information was available on anxiety, PTSD and fatigue. Meta‐analysis revealed that the measurement tool administered influenced the prevalence of cognitive impairment: Mini‐Mental State Examination 17% [95% confidence interval (CI) 7, 26]; neuropsychological test battery 39% (95% CI 28, 50); Montreal Cognitive Assessment 54% (95% CI 43, 66). There is evidence to suggest that TIA/minor stroke patients may experience residual impairments; however, results should be interpreted with caution because of the few high quality studies. Notwithstanding, it is important to raise awareness of potential subtle but meaningful residual impairments.
Environmentally driven evolution of Rubisco and improved photosynthesis and growth within the C3 genus Limonium (Plumbaginaceae)
Authors: Galmés Jeroni , Andralojc P. John , Kapralov Maxim V. , Flexas Jaume , Keys Alfred J. , Molins Arántzazu , Parry Martin A. J. , Conesa Miquel À.
Published: May 2014

Carbon assimilation by most ecosystems requires ribulose‐1,5‐bisphosphate carboxylase/oxygenase (Rubisco). Its kinetic parameters are likely to have evolved in parallel with intracellular CO2 availability, with the result that faster forms of Rubisco occur in species with CO2‐concentrating mechanisms.

The Rubisco catalytic properties were determined and evaluated in relation to growth and carbon assimilation capacity in Mediterranean Limonium species, inhabiting severe stress environments.

Significant kinetic differences between closely related species depended on two amino acid substitutions at functionally important residues 309 and 328 within the Rubisco large subunit. The Rubisco of species facing the largest CO2 restrictions during drought had relatively high affinity for CO2 (low Michaelis–Menten constant for CO2 (Kc)) but low maximum rates of carboxylation ( ), while the opposite was found for species that maintained higher CO2 concentrations under similar conditions. Rubisco kinetic characteristics were correlated with photosynthetic rate in both well‐watered and drought‐stressed plants. Moreover, the drought‐mediated decrease in plant biomass accumulation was consistently lower in species with higher Rubisco carboxylase catalytic efficiency ( /Kc).

The present study is the first demonstration of Rubisco adaptation during species diversification within closely related C3 plants, revealing a direct relationship between Rubisco molecular evolution and the biomass accumulation of closely related species subjected to unfavourable conditions.
Rapid Hebbian axonal remodeling mediated by visual stimulation
Authors: Munz Martin , Gobert Delphine , Schohl Anne , Poquérusse Jessie , Podgorski Kaspar , Spratt Perry , Ruthazer Edward S.
Published: May 2014

We examined how correlated firing controls axon remodeling, using in vivo time-lapse imaging and electrophysiological analysis of individual retinal ganglion cell (RGC) axons that were visually stimulated either synchronously or asynchronously relative to neighboring inputs in the
Xenopus laevis
optic tectum. RGCs stimulated out of synchrony rapidly lost the ability to drive tectal postsynaptic partners while their axons grew and added many new branches. In contrast, synchronously activated RGCs produced fewer new branches, but these were more stable. The effects of synchronous activation were prevented by the inhibition of neurotransmitter release and
N
-methyl-
d
-aspartate receptor (NMDAR) blockade, which is consistent with a role for synaptic NMDAR activation in the stabilization of axonal branches and suppression of further exploratory branch addition.