bluuebunny/crossref_metadata_2025 huggingface dataset:
CD13 Regulates Anchorage and Differentiation of the Skeletal Muscle Satellite Stem Cell Population in Ischemic Injury
Authors: Rahman M. Mamunur , Ghosh Mallika , Subramani Jaganathan , Fong Guo-Hua , Carlson Morgan E. , Shapiro Linda H.
Published: December 2013

CD13 is a multifunctional cell surface molecule that regulates inflammatory and angiogenic mechanisms in vitro, but its contribution to these processes in vivo or potential roles in stem cell biology remains unexplored. We investigated the impact of loss of CD13 on a model of ischemic skeletal muscle injury that involves angiogenesis, inflammation, and stem cell mobilization. Consistent with its role as an inflammatory adhesion molecule, lack of CD13 altered myeloid trafficking in the injured muscle, resulting in cytokine profiles skewed toward a prohealing environment. Despite this healing-favorable context, CD13KO animals showed significantly impaired limb perfusion with increased necrosis, fibrosis, and lipid accumulation. Capillary density was correspondingly decreased, implicating CD13 in skeletal muscle angiogenesis. The number of CD45−/Sca1−/α7-integrin+/β1-integrin+ satellite cells was markedly diminished in injured CD13KO muscles and adhesion of isolated CD13KO satellite cells was impaired while their differentiation was accelerated. Bone marrow transplantation studies showed contributions from both host and donor cells to wound healing. Importantly, CD13 was coexpressed with Pax7 on isolated muscle-resident satellite cells. Finally, phosphorylated-focal adhesion kinase and ERK levels were reduced in injured CD13KO muscles, consistent with CD13 regulating satellite cell adhesion, potentially contributing to the maintenance and renewal of the satellite stem cell pool and facilitating skeletal muscle regeneration. Stem Cells  2014;32:1564–1577
Intraoperative Neuromonitoring for Surgical Training in Thyroid Surgery: Its Routine Use Allows a Safe Operation Instead of Lack of Experienced Mentoring
Authors: Alesina P. F. , Hinrichs J. , Meier B. , Cho E. Y. , Bolli M. , Walz M. K.
Published: December 2013

Background

The aim of the present study was to evaluate the influence of intraoperative neuromonitoring (NM) on surgical training. The results of thyroidectomy performed by inexperienced surgeons under the supervision of a consultant surgeon without intraoperative neuromonitoring (ioNM) were compared to those of the operations performed without experienced assistance but under neuromonitoring control.

Materials and methods

The study included the thyroid operations performed in our Department between 2005 and 2012. Among them, residents or fellows performed 1,116 procedures. Seven hundred sixty‐five operations were conducted without neuromonitoring (NV group) and 351 with NM group. In the NV group 375 unilateral and 390 bilateral operations were performed. In the NM group 149 unilateral and 202 bilateral operations were performed. Primary end point of the study was the incidence of postoperative recurrent laryngeal nerve palsy. A secondary end point was the impact of ioNM on operating time and operative strategy.

Results

The incidence of recurrent laryngeal nerve (RLN) palsy was 2.6 % in the NV group and 2.7 % in the NM group [p = ns]. One case of bilateral RLN palsy was observed in the NV group. The operative time was longer in the NM group for both lobectomy and total thyroidectomy (50 vs. 56 min and 76 vs. 81 min, respectively; p < 0.05).

Conclusions

The routine use of intermittent intraoperative neuromonitoring during thyroid operations does not reduce the incidence of RLN palsy. Nevertheless, it allows inexperienced surgeons to perform a safe operation with a complication rate comparable to that obtained under supervision of an experienced surgeon. Moreover, ioNM could avoid the unfortunate occurrence of a bilateral RLN palsy.
Prognostic Value of CEA and CK20 mRNA in the Peritoneal Lavage Fluid of Patients Undergoing Curative Surgery for Gastric Cancer
Authors: Takata Akihiro , Kurokawa Yukinori , Fujiwara Yoshiyuki , Nakamura Yurika , Takahashi Tsuyoshi , Yamasaki Makoto , Miyata Hiroshi , Nakajima Kiyokazu , Takiguchi Shuji , Mori Masaki , Doki Yuichiro
Published: December 2013

Background

Peritoneal recurrence is the most common type of recurrence in gastric cancer. Although cytological examination of peritoneal lavage fluid has been used to predict peritoneal spread, peritoneal recurrences often occur even in patients with negative cytology. Our previous retrospective study suggested that reverse transcriptase‐polymerase chain reaction (RT‐PCR) using peritoneal lavage fluid may be useful for predicting peritoneal recurrence in patients with negative cytology. This prospective study was conducted to validate the clinical impact of this RT‐PCR method.

Methods

From July 2009 to June 2012, a total of 118 cT2‐4 gastric cancer patients underwent surgery. Since 14 patients were ineligible because they had incurable factors, the remaining 104 eligible patients were evaluated for carcinoembryonic antigen (CEA) and cytokeratin 20 (CK20) messenger RNA (mRNA) using RT‐PCR. If either CEA or CK20 mRNA was detected by RT‐PCR, the patient was defined as PCR‐positive as in our previous study. The association between recurrence‐free survival (RFS) and background factors was analyzed using Cox proportional hazards models.

Results

Of 104 patients, 16 (15.4 %) were positive for either CEA or CK20. PCR‐positive patients had significantly worse RFS than PCR‐negative patients (log‐rank p = 0.007). Regarding the pattern of recurrence, 4 of 16 (25 %) PCR‐positive patients and 2 of 88 (2 %) PCR‐negative patients had peritoneal recurrence (p < 0.001), but there were no significant differences in recurrence at other sites. Cox multivariate analysis indicated only PCR‐positivity as a significant predictor of poor RFS (p = 0.029).

Conclusion

This prospective study demonstrated that CEA and CK20 PCR results could predict peritoneal recurrence after curative surgery.
A Simple Risk Score to Predict the Presence of Non‐Sentinel Lymph Node Metastases in Breast Cancer Patients with a Positive Sentinel Node
Authors: van la Parra Raquel F. D. , Peer Petronella G. M. , de Roos Wilfred K. , Ernst Miranda F. , de Wilt Johannes H. W. , Bosscha Koop
Published: December 2013

Background

Historically, completion axillary lymph node dissection (cALND) is recommended in sentinel lymph node (SLN)‐positive patients. However, the high rate of negative non‐sentinel nodes (NSNs) in cALND and the reported low axillary recurrence rates have led to a more conservative approach. A risk score was developed to identify a patient’s individual risk for NSN metastases.

Methods

Data of 182 SLN‐positive patients who underwent cALND were used for risk score development. The risk score, consisting of pathological tumor size (≤20/>20 mm), lymphovascular invasion (no/yes), extracapsular extension (no/yes), size of metastases (≤2/>2 mm), and number of positive SLNs (1/>1), was subsequently validated on an external population (n = 180).

Results

The area under the receiver operating characteristic curve was 0.78 (95 % CI 0.71–0.85) in the original population and 0.78 (95 % CI 0.70–0.85) in the validation population. Based on the predicted risk for positive NSNs, three groups were defined: low risk (≤20 %), intermediate risk (21–50 %), and high risk (>50 %). In total, 88 patients met the Z0011 inclusion criteria and none of them had a high predicted risk. Of the 199 non‐Z0011 patients, 67 (33.7 %) had low risk, 96 (48.2 %) had intermediate risk, and 36 (18.1 %) had high risk.

Conclusion

A simple risk score, integrating just five clinicopathological variables, was developed that may assist in individual decision making regarding ALND in SLN‐positive patients outside of the Z0011 trial.
Decision science for effective management of populations subject to stochasticity and imperfect knowledge
Authors: Yokomizo Hiroyuki , Coutts Shaun R. , Possingham Hugh P.
Published: December 2013

Many species are threatened by human activity through processes such as habitat modification, water management, hunting, and introduction of invasive species. These anthropogenic threats must be mitigated as efficiently as possible because both time and money available for mitigation are limited. For example, it is essential to address the type and degree of uncertainties present to derive effective management strategies for managed populations. Decision science provides the tools required to produce effective management strategies that can maximize or minimize the desired objective(s) based on imperfect knowledge, taking into account stochasticity. Of particular importance are questions such as how much of available budgets should be invested in reducing uncertainty and which uncertainties should be reduced. In such instances, decision science can help select efficient environmental management actions that may be subject to stochasticity and imperfect knowledge. Here, we review the use of decision science in environmental management to demonstrate the utility of the decision science framework. Our points are illustrated using examples from the literature. We conclude that collaboration between theoreticians and practitioners is crucial to maximize the benefits of decision science's rational approach to dealing with uncertainty.
Meta‐models as a straightforward approach to the sensitivity analysis of complex models
Authors: Coutts Shaun R. , Yokomizo Hiroyuki
Published: December 2013

Complex simulation models are important tools in applied ecological and conservation research. However sensitivity analysis of this important class of models can be difficult to conduct. High level interactions and non‐linear responses are common in complex simulations, and this necessitates a global sensitivity analysis, where each parameter is tested at a range of values, and in combination with changes in many other parameters. We reviewed the literature, searching for population viability analyses that used simulation models. We found only 9 out of the 122 simulation population viability analysis used global sensitivity analysis. This result is typical of other simulation models in applied ecology, where global sensitivity analysis is rare. We then demonstrate how to conduct a meta‐modeling sensitivity analysis, where a simpler statistically fit function (the meta‐model, also known as the surrogate model or emulator) is used to approximate the behavior of the complicated simulation. This simpler meta‐model is interrogated to inform on the behavior of simulation model. We fit two example meta‐models, a generalized linear model and a boosted regression tree, to exemplify the approach. Our hope is that by going through these techniques thoroughly they will become more widely adopted.
Update on transcobalamin deficiency: clinical presentation, treatment and outcome
Authors: Trakadis Y. J. , Alfares A. , Bodamer O. A. , Buyukavci M. , Christodoulou J. , Connor P. , Glamuzina E. , Gonzalez‐Fernandez F. , Bibi H. , Echenne B. , Manoli I. , Mitchell J. , Nordwall M. , Prasad C. , Scaglia F. , Schiff M. , Schrewe B. , Touati G. , Tchan M. C. , Varet B. , Venditti C. P. , Zafeiriou D. , Rupar C. A. , Rosenblatt D. S. , Watkins D. , Braverman N.
Published: December 2013

Transcobalamin (TC) transports cobalamin from blood into cells. TC deficiency is a rare autosomal recessive disorder usually presenting in early infancy with failure to thrive, weakness, diarrhoea, pallor, anemia, and pancytopenia or agammaglobulinemia. It can sometimes resemble neonatal leukemia or severe combined immunodeficiency disease. Diagnosis of TC deficiency is suspected based on megaloblastic anemia, elevation of total plasma homocysteine, and blood or urine methylmalonic acid. It is confirmed by studying the synthesis of TC in cultured fibroblasts, or by molecular analysis of the TCN2 gene. TC deficiency is treatable with supplemental cobalamin, but the optimal type, route and frequency of cobalamin administration and long term patient outcomes are unknown. Here we present a series of 30 patients with TC deficiency, including an update on multiple previously published patients, in order to evaluate the different treatment strategies and provide information about long term outcome. Based on the data presented, current practice appears to favour treatment of individuals with TC deficiency by intramuscular injections of hydroxy‐ or cyanocobalamin. In most cases presented, at least weekly injections (1 mg IM) were necessary to ensure optimal treatment. Most centres adjusted the treatment regimen based on monitoring CBC, total plasma homocysteine, plasma and urine methylmalonic acid, as well as, clinical status. Finally, continuing IM treatment into adulthood appears to be beneficial.
Muscle MRI in patients with long‐chain fatty acid oxidation disorders
Authors: Diekman Eugene F. , van der Pol W. Ludo , Nievelstein Rutger A. J. , Houten Sander M. , Wijburg Frits A. , Visser Gepke
Published: December 2013

Introduction

Muscle magnetic resonance imaging (MRI) is a useful tool for visualizing abnormalities in neuromuscular disorders. The value of muscle MRI has not been studied in long‐chain fatty acid oxidation (lcFAO) disorders. LcFAO disorders may present with metabolic myopathy including episodic rhabdomyolysis.

Objective

To investigate whether lcFAO disorders are associated with muscle MRI abnormalities.

Methods

Lower body MRI was performed in 20 patients with lcFAO disorders, i.e. three carnitine palmitoyltransferase 2 deficiency (CPT2D), 12 very long‐chain acyl‐CoA dehydrogenase deficiency (VLCADD), three mitochondrial trifunctional protein deficiency (MTPD) and two isolated long‐chain hydroxyacyl‐CoA dehydrogenase deficiency (LCHADD).

Results

At the time of MRI, four patients had muscle weakness, 14 had muscle pain and 13 were exercise intolerant. Median creatine kinase (CK) level of patients at the day of MRI was 398 U/L (range 35‐12,483). T1W and STIR signal intensity (SI) were markedly increased in MTPD patients from girdle to lower leg. VLCADD patients showed predominantly proximal T1W SI changes, whereas LCHADD patients mostly showed distal T1W SI changes. Prominent STIR weighted signal intensity increases of almost all muscle groups were observed in patients with VLCADD and LCHADD with very high CK (>11.000) levels.

Conclusions and relevance

lcFAO disorders are associated with specific patterns of increased T1W and STIR signal intensity. These patterns may reflect lipid accumulation and inflammation secondary to lcFAO defects and progressive muscle damage. Future studies are needed to investigate whether muscle MRI might be a useful tool to monitor disease course and to study pathogenesis of lcFAO related myopathy.
Comment on the Asymptotics of a Distribution-Free Goodness of Fit Test Statistic
Authors: Browne Michael W. , Shapiro Alexander
Published: December 2013

In a recent article Jennrich and Satorra (Psychometrika 78: 545–552, 2013) showed that a proof by Browne (British Journal of Mathematical and Statistical Psychology 37: 62–83, 1984) of the asymptotic distribution of a goodness of fit test statistic is incomplete because it fails to prove that the orthogonal component function employed is continuous. Jennrich and Satorra (Psychometrika 78: 545–552, 2013) showed how Browne’s proof can be completed satisfactorily but this required the development of an extensive and mathematically sophisticated framework for continuous orthogonal component functions. This short note provides a simple proof of the asymptotic distribution of Browne’s (British Journal of Mathematical and Statistical Psychology 37: 62–83, 1984) test statistic by using an equivalent form of the statistic that does not involve orthogonal component functions and consequently avoids all complicating issues associated with them.
Enzamin ameliorates adipose tissue inflammation with impaired adipocytokine expression and insulin resistance in db/db mice
Authors: Tamura Yukinori , Yano Masato , Kawao Naoyuki , Okumoto Katsumi , Ueshima Shigeru , Kaji Hiroshi , Matsuo Osamu
Published: December 2013

The effects of Enzamin on obesity-related metabolic disorders in obese db/db mice were examined to explore a novel agent for the prevention of insulin resistance. Db/db mice were treated with water containing Enzamin (0·1 and 1·0 %) for 8 weeks from 6 weeks of age. Enzamin treatment at 1·0 %, but not at 0·1 %, significantly decreased the fasting plasma glucose, serum total cholesterol and TAG levels in db/db mice, without affecting body weight gain and body fat composition. Furthermore, insulin sensitivity and glucose tolerance were improved by the treatment of db/db mice with 1·0 % Enzamin. Immunohistochemical studies and gene expression analysis showed that 1·0 % Enzamin treatment suppressed macrophage accumulation and inflammation in the adipose tissue. In addition, 1·0 % Enzamin treatment increased serum adiponectin in db/db mice. Treatment with 1·0 % Enzamin also significantly suppressed the expression of NADPH oxidase subunits, suggesting an antioxidative effect for Enzamin in the adipose tissue. Furthermore, in vitro experiments demonstrated that the lipopolysaccharide-induced inflammatory reaction was significantly suppressed by Enzamin treatment in macrophages. Enzamin treatment increased the expression of GLUT4 mRNA in muscle, but not GLUT2 mRNA in the liver of db/db mice. Enzamin also increased the mRNA expression of carnitine palmitoyltransferase 1a (CPT1a, muscle isoform) in db/db mice, whereas Enzamin treatment did not affect the mRNA expression of CPT1b (liver isoform) in db/db mice. In conclusion, our data indicate that Enzamin can improve insulin resistance by ameliorating impaired adipocytokine expression, presumably through its anti-inflammatory action, and that Enzamin possesses a potential for preventing the metabolic syndrome.
Dual Identity Under Threat
Authors: Fleischmann Fenella , Phalet Karen , Swyngedouw Marc
Published: December 2013

Drawing on the literatures on dual identity and politicization, this study relates the political engagement of European-born Muslims to their dual identification as ethno-religious minorities and as citizens. Minorities’ political engagement may target mainstream society and/or ethno-religious communities. Surveying the Turkish and Moroccan Belgian second generation, our study analyzes their support for religious political assertion, participation in ethno-religious and mainstream organizations, and trust in civic institutions. Its explanatory focus is on the dual ethno-religious and civic identifications of the second generation and on perceived discrimination and perceived incompatibility as threats to their dual identity. Our findings show that participation in organizations beyond the ethno-religious community is most likely among high civic and low ethnic identifiers, and lower among dual identifiers. Rather than increasing political apathy, perceived discrimination goes along with higher levels of participation in both ethno-religious and mainstream organizations. Finally, the perception of Islamic and Western ways of life as incompatible predicts greater support for religious political assertion and lower trust in civic institutions. Implications for the role of dual identity and identity threat in the political integration of ethno-religious minorities are discussed.
A New Role for Downstream Toll-like Receptor Signaling in Mediating Immediate Early Gene Expression during Focal Cerebral Ischemia
Authors: Famakin Bolanle M , Mou Yongshan , Johnson Kory , Spatz Maria , Hallenbeck John
Published: December 2013

To better understand the role of downstream Toll-like receptor (TLR) signaling during acute cerebral ischemia, we performed cDNA microarrays, on brain RNA, and cytokine arrays, on serum, from wild type (WT), MyD88−/− and TRIF-mutant mice, at baseline and following permanent middle cerebral artery occlusion (pMCAO). The acute stress response pathway was among the top pathways identified by Ingenuity Pathway Analysis of microarray data. We used real-time polymerase chain reaction to confirm the expression of four immediate early genes; EGR1, EGR2, ARC, Nurr77, in this pathway, and insulin degrading enzyme (IDE). Compared to WT, baseline immediate early gene expression was increased up to10-fold in MyD88−/− and TRIF-mutant mice. However, following pMCAO, immediate early gene expression remained unchanged, from this elevated baseline in these mice, but increased up to 12-fold in WT. Furthermore, expression of IDE, which also degrades β-amyloid, decreased significantly only in TRIF-mutant mice. Finally, sE-Selectin, sICAM, sVCAM-1, and MMP-9 levels were significantly decreased only in MyD88−/− compared with WT mice. We thus report a new role for downstream TLR signaling in immediate early gene expression during acute cerebral ischemia. We also show that the TRIF pathway regulates IDE expression; a major enzyme that clears β-amyloid from the brain.
Delayed Progesterone Treatment Reduces Brain Infarction and Improves Functional Outcomes after Ischemic Stroke: A Time-Window Study in Middle-Aged Rats
Authors: Yousuf Seema , Sayeed Iqbal , Atif Fahim , Tang Huiling , Wang Jun , Stein Donald G
Published: December 2013

We evaluated the neuroprotective effects of delayed progesterone (PROG) treatment against ischemic stroke-induced neuronal death, inflammation, and functional deficits. We induced transient focal cerebral ischemia in male rats and administered PROG (8 mg/kg) or vehicle intraperitoneally at 3, 6, or 24 hours post occlusion, subcutaneously 5 hours later and then every 24 hours for 7 days. Behavioral outcomes were evaluated over 22 days. Infarct size and other biomarkers of injury were evaluated by cresyl violet staining, and matrix metalloproteinase-9 (MMP-9), glial fibrillary acidic protein (GFAP), and vascular endothelial growth factor (VEGF) by immunofluorescence. Progesterone treatment started at 3 and 6 hours post occlusion significantly ( P<0.05) improved behavioral performance at all time points (74.01%) and reduced infarction volume (61.68%) compared with vehicle. No significant difference was observed between the 3 and 6 hour PROG treatment groups. Matrix metalloproteinase-9 and VEGF were upregulated in the PROG groups compared with vehicle. Glial fibrillary acidic protein expression was increased in the vehicle group but markedly lower in the PROG groups. Treatment delayed for 24 hours did not significantly improve functional outcomes or reduce infarction volume. We conclude that, under the right treatment conditions, PROG treatment delayed up to 6 hours can improve functional deficits and reduce brain infarction, possibly by modulating GFAP, VEGF, and MMP-9 expression.
Hypothalamic Astroglial Connexins are Required for Brain Glucose Sensing-Induced Insulin Secretion
Authors: Allard Camille , Carneiro Lionel , Grall Sylvie , Cline Brandon H , Fioramonti Xavier , Chrétien Chloé , Baba-Aissa Fawzia , Giaume Christian , Pénicaud Luc , Leloup Corinne
Published: December 2013

Hypothalamic glucose detection participates in maintaining glycemic balance, food intake, and thermogenesis. Although hypothalamic neurons are the executive cells involved in these responses, there is increasing evidence that astrocytes participate in glucose sensing (GS); however, it is unknown whether astroglial networking is required for glucose sensitivity. Astroglial connexins 30 and 43 (Cx30 and Cx43) form hexameric channels, which are apposed in gap junctions, allowing for the intercellular transfer of small molecules such as glucose throughout the astroglial networks. Here, we hypothesized that hypothalamic glucose sensitivity requires these connexins. First, we showed that both Cxs are enriched in the rat hypothalamus, with highly concentrated Cx43 expression around blood vessels of the mediobasal hypothalamus (MBH). Both fasting and high glycemic levels rapidly altered the protein levels of MBH astroglial connexins, suggesting cross talk within the MBH between glycemic status and the connexins' ability to dispatch glucose. Finally, the inhibition of MBH Cx43 (by transient RNA interference) attenuated hypothalamic glucose sensitivity in rats, which was demonstrated by a pronounced decreased insulin secretion in response to a brain glucose challenge. These results illustrate that astroglial connexins contribute to hypothalamic GS.
Changes in Cerebral Blood Flow during Steady-State Cycling Exercise: A Study Using Oxygen-15-Labeled Water with PET
Authors: Hiura Mikio , Nariai Tadashi , Ishii Kenji , Sakata Muneyuki , Oda Keiichi , Toyohara Jun , Ishiwata Kiichi
Published: December 2013

Cerebral blood flow (CBF) during dynamic exercise has never been examined quantitatively using positron emission tomography (PET). This study investigated changes in CBF that occur over the course of a moderate, steady-state cycling exercise. Global and regional CBF (gCBF and rCBF, respectively) were measured using oxygen-15-labeled water (H215O) and PET in 10 healthy human subjects at rest (Rest), at the onset of exercise (Ex1) and at a later phase in the exercise (Ex2). At Ex1, gCBF was significantly ( P<0.01) higher (27.9%) than at Rest, and rCBF was significantly higher than at Rest in the sensorimotor cortex for the bilateral legs (M1Leg and S1Leg), supplementary motor area (SMA), cerebellar vermis, cerebellar hemispheres, and left insular cortex, with relative increases ranging from 37.6% to 70.5%. At Ex2, gCBF did not differ from Rest, and rCBF was significantly higher (25.9% to 39.7%) than at Rest in only the M1Leg, S1Leg, and vermis. The areas showing increased rCBF at Ex1 were consistent with the central command network and the anatomic pathway for interoceptive stimuli. Our results suggest that CBF increases at Ex1 in parallel with cardiovascular responses then recovers to the resting level as the steady-state exercise continues.
Ultrasensitive detection of 3′-5′ exonuclease enzymatic activity using molecular beacons
Authors: Wu Xu , Chen Jiao , Zhao Julia Xiaojun
Published: December 2013

An ultrasensitive and rapid fluorescence assay was developed for the detection of 3′-5′ exonuclease activity using molecular beacons.
Pyridine- and pyrimidine-functionalized poly(sulfone)s: performance-enhancing crosslinkers for acid/base blend proton exchange membranes used in direct methanol fuel cells
Authors: Varnado C. Daniel , Zhao Xinsheng , Ortiz Michael , Zuo Zicheng , Jiang Zhongqing , Manthiram Arumugam , Bielawski Christopher W.
Published: December 2013

New N-heterocycle-functionalized poly(sulfone)s, which were readily prepared under mild conditions, served as performance-enhancing additives for proton exchange membranes used in direct methanol fuel cells.
Synthesis of 5′-carboxymethylsulfonyl-5′-deoxyribonucleosides under mild hydrolytic conditions: a new class of acidic nucleosides as inhibitors of ribonuclease A
Authors: Datta Dhrubajyoti , Samanta Anirban , Dasgupta Swagata , Pathak Tanmaya
Published: December 2013

Trimethyltin hydroxide mediated synthesis of a new class of RNase A inhibitors. The cytidine analogue emerged as the most efficient inhibitor with aKivalue of 22 ± 2 μM.
Fabrication methods for performance improvement of Cu(In,Ga)Se2 thin film solar cells
Authors: Choi P.H. , Baek D.H. , Kim H.J. , Kim K.S. , Park H.S. , Kim S.S. , Choi B.D.
Published: December 2013

Two advanced fabrication methods are introduced: the hydrogen peroxide (H2O2)‐added chemical bath deposition technique and molybdenum (Mo) back‐contact formation under 3 kW sputter power. The parameters of the short circuit current density (JSC) and conversion efficiency (η) were improved over standard cells when the ZnS buffer layer was deposited in the H2O2‐added chemical solution. Otherwise, the fill‐factor and η were best at 3 kW Mo sputtering power conditions. Advanced fabrication methods are realised to improve cell performance without modifying the chemical composition of the Cu(In,Ga)Se2 absorption layer.
Multiplierless approximate 4‐point DCT VLSI architectures for transform block coding
Authors: Bayer F.M. , Cintra R.J. , Madanayake A. , Potluri U.S.
Published: December 2013

Two multiplierless algorithms are proposed for 4 × 4 approximate‐discrete cosine transform (DCT) for transform coding in digital video. Computational architectures for one‐dimensional (1D)/2D realisations are implemented using Xilinx field programmable gate array devices. CMOS synthesis at the 45 nm node indicates real‐time operation at 1 GHz yielding 4 × 4 block rates of 125 MHz at < 120 mW of dynamic power consumption.
High‐resolution imaging of defects in CdTe solar cells using thermoreflectance
Authors: Katz N. , Patterson M. , Zaunbrecher K. , Johnston S. , Hudgings J.
Published: December 2013

Thermal imaging of solar cells is important for diagnosing non‐uniform operation or point defects, which can reduce cell efficiency. However, imaging with infrared light is impractical for superstrate CdTe cells because the glass substrate blocks transmission of light. It is shown that thermoreflectance – a lock‐in technique that detects changes in the reflectivity of visible light – can circumvent this problem and achieve thermal images with spatial resolution limited only by the imaging wavelength. The diagnostic is used to show that a particular defect is a resistive shunt.
Single‐radio multi‐subchannel random access for OFDMA wireless networks
Authors: Xu Jia , Lv Pin , Wang Xudong
Published: December 2013

Orthogonal frequency division multiple access (OFDMA) is a promising technology owing to its flexibility in subcarrier/subchannel allocation. Since most applications in OFDMA wireless networks generate bursty traffic, it is efficient and flexible to employ a random access mechanism in such networks. A single‐radio multi‐subchannel carrier sense multiple access with collision avoidance (CSMA/CA)‐based random access protocol (called SRMC‐CSMA/CA) is proposed for OFDMA wireless networks. By means of intermittent carrier sense and cumulative update of backoff counters, a terminal with a single radio can utilise multiple subchannels to transmit packets concurrently. Simulation results indicate that the SRMC‐CSMA/CA protocol apparently improves the channel utilisation, especially when the traffic loads of the terminals are unbalanced.
Continuous‐flow variable‐length memoryless linear regression architecture
Authors: Garrido M. , Grajal J.
Published: December 2013

A pipelined circuit to calculate linear regression is presented. The proposed circuit has the advantages that it can process a continuous flow of data, it does not need memory to store the input samples and supports variable length that can be reconfigured in run time. The circuit is efficient in area, as it consists of a small number of adders, multipliers and dividers. These features make it very suitable for real‐time applications, as well as for calculating the linear regression of a large number of samples.
Dynamic PCI assignment in two‐tier networks based on cell activity prediction
Authors: Zhang X. , Liu E.J. , Xiao Z. , Zhang J.
Published: December 2013

Physical cell identity (PCI) is used to identify each cell. However, with the introduction of femtocells, 8 bytes allocation for PCI cannot accommodate a large number of femtocells. The current solution in 3GPP Release 9 is to use cell global identity associated with PCI to resolve this problem. However, this solution may incur higher inbound handover failure. A dynamic PCI assignment based on cell activity level prediction is proposed. The system level simulation showed that the approach outperforms the existing approaches.
Near‐field switched loop antenna array with circular defected ground structure for precise positioning systems
Authors: Lee W.‐S. , Jang H.‐S. , Oh K.‐S. , Yu J.‐W.
Published: December 2013

A near‐field switched loop antenna array with a circular defected ground structure for precise positioning systems is presented. By switching the loop array, the positions of the densely placed small‐sized radio frequency identification tags can be identified. The characteristics of the proposed array are verified by the comparisons to the simulated results and experimental measurements.
Design of phase codes with interval staggering for Doppler ambiguous target detection
Authors: Wei Na , Zhang Linke
Published: December 2013

The design of radar coherent pulse trains encoded with interval staggering for ambiguous Doppler target detection in clutter is addressed. To alleviate the Doppler ambiguous problem, an interpulse phase coding optimisation model is formulated in terms of staggered interval sampling, while maximising the output signal‐to‐interference‐plus‐noise ratio for improved target detection. Based on a reformulation of this optimisation problem as a non‐convex quadratically constrained quadratic program (QCQP), a semidefinite relaxation algorithm for this QCQP is presented. Numerical results demonstrate the effectiveness of this proposed approach.
9.5 dB relative intensity noise reduction in quantum cascade laser by detuned loading
Authors: Juretzka C. , Breuer S. , Drzewietzki L. , Schad F. , Carras M. , Elsäßer W.
Published: December 2013

The possibility of reducing the relative intensity noise (RIN) of a quantum cascade laser is demonstrated. By phase‐dependent optical feedback from a short, piezo‐controlled external cavity configuration, it is possible to achieve up to 9.5 dB of RIN reduction. These findings are consistently explained by a detuned loading approach based on modifying the alpha parameter.
Solar cell stacked dual‐polarised patch antenna for 5.8 GHz band WiMAX network
Authors: Yurduseven O. , Smith D.
Published: December 2013

A novel combination of a two‐port slant ± 45° dual‐polarised microstrip patch antenna with a polycrystalline silicon (poly‐Si) solar cell operating as an RF stacked parasitic patch element is presented and discussed for 5.8 GHz band polarisation diverse multifunctional WiMAX systems. To minimise the effect of the solar operation on the RF antenna performance, an effective DC/RF isolation circuit consisting of quarter‐wavelength microstrip transmission lines is demonstrated. The proposed solar patch provides identical E‐plane and H‐plane far‐field radiation patterns for +45° and −45° polarisations with a gain of 7.8 dBi and operates at the frequency band of 5.66–5.91 GHz.
Frequency‐agile load‐modulated magnetic resonance wireless power transfer system for reliable near‐field in‐band signalling
Authors: Kim N.Y. , Yoon S.‐W. , Kim C.‐W.
Published: December 2013

A frequency‐agile load modulation scheme is proposed for reliable near‐field magnetic communication with a magnetic resonance wireless power transfer system. A working prototype of the system to realise concurrent power and data transfer in the high‐frequency band has been fabricated to verify that demodulation of the load modulation signal state detected on the transmitter side is stable over the distance ranges covering the near‐field coupling region. This scheme can be a simple and efficient solution against potential issues such as non‐communication and envelope inversion arising from strong magnetic resonance coupling.
Design of high gain, broadband cylindrical dielectric resonator antenna
Authors: Wang Y.‐F. , Denidni T.A. , Zeng Q.‐S. , Wei G.
Published: December 2013

A new high‐gain cylindrical dielectric resonator antenna (DRA) with a large bandwidth is proposed. A cylindrical dielectric resonator, an intermediate layer and a metallic cylinder are used to obtain a large bandwidth and a high gain. The intermediate layer structure can suppress surface wave propagation, which results in a gain improvement, and the cavity formed by the metallic cylinder provides a further higher gain. The measured results demonstrate that the proposed DRA achieves a large bandwidth of 23% from 5.4 to 6.8 GHz with a voltage standing wave ratio of < 2 and a high gain of around 11 dBi.
40 Gbit/s data routing through scalable 2D matrix of higher‐order ring resonator switches
Authors: DasMahapatra P. , Stabile R. , Rohit A. , Williams K.A.
Published: December 2013

The first 40 Gbit/s multipath data routing is demonstrated in a two‐dimensional switch matrix composed of high‐order resonant optical switches. Broadband connectivity with on‐state bandwidths exceeding 100 GHz, chip losses below 9.0 dB and signal extinction above 20 dB is achieved through the four paths on the diagonal of the 4 × 4 matrix. 40 Gbit/s data routing is demonstrated through three of these paths with power penalties below 0.5 dB for each path.
Low complexity DCT for image compression in wireless visual sensor networks
Authors: Kouadria N. , Doghmane N. , Messadeg D. , Harize S.
Published: December 2013

An energy‐efficient discrete cosine transform (DCT) is proposed. It can be used in image compression in wireless visual sensor networks. It is a combination of the recently proposed block discrete cosine transform and a pruned approach. Thus, the computational complexity is reduced significantly. The experimental results show that the proposed transform leads to a significant reduction in computation time at the target sensor node. This will consequently result in a saving in energy consumption. The proposed DCT is very suitable for implementation in wireless sensor networks powered by batteries.
Hyperbolically frequency modulated transducer in SAW sensors and tags
Authors: Plessky V. , Lamothe M.
Published: December 2013

A linear frequency modulated transducer was earlier proposed for use in surface acoustic wave (SAW) tags and sensors. This reported work demonstrates that the hyperbolically frequency modulated (HFM) transducer has significant advantages for such devices often operating in a wide range of temperatures. The HFM transducer is practically insensitive to wide temperature variations, which expand or compress signals in time. Owing to the exponential change of the varying period with the electrode number, the expansion of the length of all the periods is equivalent to just a shift in time and the compressed signal remains practically unchanged in shape, just slightly shifted. Such a shift has no importance for SAW sensors/tags, which usually operate on the difference of delays of the compressed peaks.
Polarisation diversity antenna with asymmetrical Y‐shaped feed structure
Authors: Sung Y.
Published: December 2013

A reconfigurable antenna with polarisation diversity is proposed. The proposed antenna consists of a square radiating patch and a switchable Y‐shaped feed structure. The radiating patch is fed by the switchable Y‐shaped feed line to dynamically change the polarisation state. The novel structure described here enables matched input optimisation for both polarisations. Low cross‐polarisation levels in the linear state and good axial ratios in the circular state are observed.
Robust phase unwrapping algorithm
Authors: Xu Z. , Huang B. , Xu S.
Published: December 2013

Phase unwrapping techniques remove the modulus 2π ambiguities of the wrapped phase. A robust phase unwrapping algorithm is proposed which reduces the probability of generating spurious phase jumps. Simulation results confirm that the new algorithm has better performance than the existing method at a low signal‐to‐noise ratio.
Experimental demonstration of nonlinear waveform‐dependent metasurface absorber with pulsed signals
Authors: Wakatsuchi H. , Rushton J.J. , Lee J. , Gao F. , Jacob M. , Kim S. , Sievenpiper D.F.
Published: December 2013

The absorbing performance of a nonlinear waveform‐dependent metasurface with pulsed signals is demonstrated. The metasurface is a periodic structure containing diodes, capacitors and resistors. These enable us to first rectify a high‐power incoming signal to a static field, then store the energy during the illumination and dissipate it before the next pulse comes in. The incident pulses contain a finite width of spectrum of around 4.2 GHz. By using the nonlinear metasurface, absorption that depends on both the power and the duty cycle of the incoming signals is measured. These measurements demonstrate the first waveform‐dependent absorbing metasurface.
Enhanced passive equaliser using open‐stub structure
Authors: Wu S.M. , Huang S.H. , Wang H.Y. , Chiu C.T. , Hung C.P. , Kuo C.W. , Wang C.C.
Published: December 2013

An open‐stub compensation technique is proposed for passive equalisers used in high‐speed digital communication systems. By simply lumping an open stub to the conventional RL‐type passive equaliser, the frequency‐dependent channel loss from the long transmission path can be compensated, the frequency response of the channel becomes more flat and the bandwidth is wider. On comparing the proposed passive equaliser with typical RL passive equalisers, the simulation results show that the proposed technique can achieve an improvement by 1 GHz in the flat region of S21 on a 60 cm‐long differential pair. Thus, the proposed technique successfully demonstrates an improvement in electrical performance of about 57.4% in the time domain.
Application of graphene oxide for reduction of thermal resistance of high‐power laser diodes
Authors: Da˛browska E. , Teodorczyk M. , Lipińska L. , Koziński R. , Mala˛g A.
Published: December 2013

Improvement of the removal efficiency of the upper (directed towards the n‐side) heat flux from high‐power laser diodes is proposed by providing the graphene‐oxide (GO) deposit from the top of the p‐down‐mounted chips. Resulting decrease of the device's thermal resistance has been found in reduced red shift of the spectral characteristics connected with the drive current increase (compared with ‘no GO deposit’ device). Providing GO in the form of aqueous suspension and then drying at room temperature is relatively easy and repeatable. Experimental step‐by‐step processing and characterisations indicate dominant heat removal from the chip's side walls rather than from its n‐contact surface.
Efficient technique for excess loop delay compensation in continuous‐time ΔΣ modulators
Authors: Zhang Y. , Chen C.H. , Temes G.C.
Published: December 2013

A highly digital technique is proposed for excess loop delay (ELD) compensation in multi‐bit continuous‐time ΔΣ modulators. A digitally controlled reference switching matrix is used to replace the power‐hungry signal adder and extra DAC driving the quantiser, which are commonly used in ELD compensation. With the proposed technique, the feedback DAC is embedded in the quantiser and implemented by a few switches. Thus, it allows low‐voltage and low‐power operation.
Low complexity Wizard amplitude shaping system for peak‐to‐average power ratio reduction
Authors: Saad Waleed , El‐Fishawy Nawal , El‐Rabaie Sayed , Shokair Mona
Published: December 2013

Orthogonal frequency division multiplexing (OFDM) is a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wide‐band digital communication. Despite its advantages, it has a major drawback of its high peak‐to‐average power ratio (PAPR) value which degrades its efficiency and increases its cost. In this study, two proposed systems are discussed to reduce the PAPR value. They depend on a signal conversion to an approximated triangle signal by means of a proposed Wizard amplitude shaping encoder. The whole characteristics mathematical analysis are presented for the proposed systems. In addition, the complexity evaluations, reliability, in‐band distortion; in terms of error vector magnitude, time and frequency domain behaviours are explained. The two proposed systems are compared with the conventional OFDM system in terms of PAPR and bit error rate under additive white Gaussian noise channel and multipath fading channels. Furthermore, the impacts of the proposed schemes design parameters, are studied.
Rate enhancement for cognitive radios using the relationship between transmission rate and signal‐to‐interference ratio statistics
Authors: Shiung David , Yang Ya‐Yin
Published: December 2013

A cognitive radio (CR) tries to intelligently utilise the idle periods of the primary system (PS) for opportunistic transmission and can improve the overall spectral utilisation. When a signal is transmitted, the authors usually consider the spectral occupancy from all propagation directions and assume circular signal coverage. In this study, they derive the relationship between transmission rate and signal‐to‐interference ratio statistics in a CR network (CRN) while protecting the rate of the PS to a specified level. Applying this relationship to a CR, they show that the regions for a CR receiver to keep an outage probability and bit error rate, defined as permissible areas, are no longer concentric in shape even in a pure path loss channel. Through detecting which permissible area a CR receiver is located, a new cognitive cycle is developed for rate enhancement. Simulation results show that as compared with a distance‐dependent rate‐adaptation approach, the system sum‐rate increases significantly. These results suggest a new version of CRN with enhanced system capacity.
Multi‐objective resource allocation in multiuser orthogonal frequency division multiplexing system
Authors: Sharma Nitin , Anpalagan Alagan
Published: December 2013

This study presents a new technique for resource allocation in multiuser orthogonal frequency division multiplexing systems. The goal is to maximise the minimum data rate available to any user while minimising the total transmitted power. The strength Pareto evolutionary algorithm (SPEA‐2) is used to achieve this goal. The SPEA‐2 algorithm solves the contradicting multiple objectives by evaluating individual's fitness value based on the number of external non‐dominated individuals that dominate it and then searching the solution space to minimise this fitness value. Most of the existing multi‐objective solutions, for the problem under consideration, have used binary coded chromosomes which restricted the number of users to be in power of two only. This limitation is overcome in the proposed scheme by using an integer coded chromosome. The population density information is also incorporated into the fitness function to refine the search. Simulation results indicate that the proposed algorithm achieves higher data rates as compared with previous algorithms. Furthermore, the proposed scheme allocates both subcarriers and bits jointly, without being computationally expensive. The faster convergence of the algorithm to near‐optimal value, as compared with previous algorithms is indicative of its reduced complexity, which is attributed to the modification in the power objective.
Compressive tracking via oversaturated sub‐region classifiers
Authors: Zhu Qiuping , Yan Jia , Deng Dexiang
Published: December 2013

This study proposed a tracking algorithm based on oversaturated sub‐region classifiers. Compared with the compressive tracking (CT), the tracker can reduce the influence of occlusion and improve the stability and accuracy of tracking result. First, the target region is divided into oversaturated sub‐regions randomly, and then some sub‐region classifiers are adaptively selected based on their confidence. Each selected classifier can find a candidate target position. At last, the place with the maximum candidate positions’ distribution density is the final location of the target. Experiments on different videos demonstrate that the proposed algorithm has stronger anti‐occlusion ability than the CT and is more robust and stable than the traditional sub‐region‐based tracking algorithm.
Data‐mining process: application for hand detection in contact free settings
Authors: Jemaa Salma Ben , Hammami Mohamed , Ben‐Abdallah Hanene
Published: December 2013

Hand detection is the first step of any hand biometric recognition process, which determines the outcome of the following treatments. In this study, the authors propose a robust method for hand detection without contact and without constraints on the capture environment. This method is based on a data‐mining process for skin‐colour modelling. The presented data‐mining process offers several advantages like the choice of the most relevant colour axes and the automatic choice of the decision rules. To improve the achieved results of skin detection and to determine the hand region in the image, a succession of postprocessings was proposed. The authors hand detection method was evaluated experimentally on a real database, namely, ‘Sfax‐Miracl hand database’; the outcomes of this evaluation show promising results and demonstrate the effectiveness of the proposed method.