bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantification of black carbon in marine systems using the benzene polycarboxylic acid method: a mechanistic and yield study
Authors: Ziolkowski L. A. , Chamberlin A.R. , Greaves J. , Druffel E.R.M.
Published: April 2011

Quantification of black carbon (BC), carbonaceous material of pyrogenic origin, has typically required either chemical or thermal oxidation methods for isolation from heterogeneous matrices, such as sediment or soil. The benzene polycarboxylic acid (BPCA) method involves chemical oxidation of aromatic structures, such as those in BC, into BPCAs. We revised the BPCA method with the intent to quantify BC in marine dissolved organic carbon (DOC). As part of this work, we evaluated the mechanism and yield of the method using nine polycyclic aromatic hydrocarbons (PAHs) and six BC reference materials. After 8 h of oxidation at 180°C, the average carbon yield was 26 ± 7% C and was not correlated to the molecular weight of the PAH oxidized. The majority of observed BPCAs were nitrated, which has serious implications for the quantification of BC. Smaller PAHs favor the formation of less substituted BPCAs, whereas larger PAHs, such as coronene, favor the formation of more fully substituted BPCAs. Time‐course experiments revealed variations of BPCA distributions over time, favoring less substituted BPCAs with longer oxidation times, whereas the carbon yield exhibited little variation. No decarboxylation of fully substituted mellitic acid (B6CA) was observed during time course experiments. Using the model compound anthracene, a potential internal standard, we propose a mechanism for the oxidation reaction based on time‐course experiment data. Quantification of BC in reference materials revealed that this revision of the BPCA method is significantly more efficient than previous versions and is effective for quantifying both char and soot BC.
In situ determination of total dissolved inorganic carbon by underwater membrane introduction mass spectrometry
Authors: Bell Ryan J. , Short R. Timothy , Byrne Robert H.
Published: April 2011

Procedures have been developed for the determination of total dissolved inorganic carbon (DIC) in acidified seawater using an underwater mass spectrometer. Factors affecting the response of the membrane introduction mass spectrometer (MIMS) system were examined to optimize calibrations and enhance the accuracy of component ocean carbon system measurements. Laboratory studies examined the following influences on MIMS measurements of DIC: bicarbonate and carbonate contributions to the MIMS CO2 signal intensity, linearity of MIMS response over a wide range of carbon dioxide concentrations, influence of sample salinity on membrane permeability, and capability to use acidified solutions for calibrations of both DIC and CO2 fugacity. It was observed that (a) bicarbonate and carbonate contributions to carbon dioxide signal intensity were significant at slow flow rates, (b) MIMS response was linearly dependent on DIC within the concentration range of interest, (c) salinity has a discernable influence on membrane permeability that is, in turn, dependent on hydrostatic pressure, and (d) well calibrated MIMS measurements for both DIC and CO2 fugacity can be obtained using acidified DIC standards. High flow rates are required during CO2 fugacity measurements in circumneutral seawater to eliminate signal contributions from bicarbonate and carbonate.
Comparison of cancer incidence between production and office workers at a shipyard in Korea: A retrospective cohort study from 1992 to 2005
Authors: Jeong Kyoung‐Sook , Kim Yangho , Kim Moon‐Chan , Yoo Cheol‐In
Published: April 2011

Background

Cancer is a major concern in shipbuilding. Since 1970s, shipbuilding and repair has been a strategic industry in Korea, which has become currently the world's largest shipbuilding country. The aim of this study is to investigate the cancer incidence in shipyard workers in Korea.

Methods

The cohort comprised 30,288 male employees (20,647 production workers and 9,641 office workers) ever employed between 1992 and 2005 in a shipyard in Korea. The authors compared the cancer incidence between the groups using the participants' hospital medical records and data received from Korea National Cancer Incidence Database and Korean National Statistical Office.

Results

The total number of cancers was 135 among office workers and 519 among production workers in the shipyard. The age‐standardized cancer rates among office and production workers were 136.2 and 179.7 per 100,000 person‐years, respectively. The standardized rate ratios for stomach cancer, liver cancer, and lung cancer in production workers compared with office workers were 1.67 (95% CI: 1.12–2.49), 2.13 (95% CI: 1.37–3.36), and 3.71 (95% CI: 1.68–8.19), respectively.

Conclusions

The observed increase in stomach, liver, and lung cancers among production workers suggests that some occupational factors in the shipyard might have contributed to the increased cancer risk. Further study is needed to clarify the risk of those cancers and to identify the specific factors involved. Am. J. Ind. Med. 54:719–725, 2011. © 2011 Wiley‐Liss, Inc.
The Hubble parameter in the early universe with viscous QCD matter and finite cosmological constant
Authors: Tawfik A.
Published: April 2011

The evolution of a flat, isotropic and homogeneous universe is studied. The background geometry in the early phases of the universe is conjectured to be filled with causal bulk viscous fluid and dark energy. The energy density relations obtained from the assumption of covariant conservation of energy‐momentum tensor of the background matter in the early universe are used to derive the basic equation for the Hubble parameter H. The viscous properties described by ultra‐relativistic equations of state and bulk viscosity taken from recent heavy‐ion collisions and lattice QCD calculations have been utilized to give an approximate solution of the field equations. The cosmological constant is conjectured to be related to the energy density of the vacuum. In this treatment, there is a clear evidence for singularity at vanishing cosmic time t indicating the dominant contribution from the dark energy. The time evolution of H seems to last for much longer time than the ideal case, where both cosmological constant and viscosity coefficient are entirely vanishing.
Association of hepatocyte growth factor promoter polymorphism with severity of interstitial lung disease in Japanese patients with systemic sclerosis
Authors: Hoshino Kana , Satoh Takashi , Kawaguchi Yasushi , Kuwana Masataka
Published: April 2011

Objective

To examine associations of single‐nucleotide polymorphisms (SNPs) within genes for hepatocyte growth factor (HGF) and its receptor c‐met with disease susceptibility and organ involvement in Japanese patients with systemic sclerosis (SSc).

Methods

Four SNPs (HGF –1652 C/T, +44222 C/T, and +63555 G/T, and c‐met –980 T/A) were analyzed in 159 SSc patients and 103 healthy control subjects with the use of a polymerase chain reaction–based assay. The influence of the HGF –1652 SNP on transcription activity was evaluated with a luciferase reporter assay and an electrophoretic mobility shift assay (EMSA).

Results

There was no difference in the distribution of HGF/c‐met SNPs between SSc patients and controls. HGF –1652 TT was found much more frequently in SSc patients with end‐stage lung disease (ESLD) than in those without (41% versus 8%; P = 0.0004). This association was confirmed by a replication study involving a separate cohort of 155 SSc patients. Kaplan‐Meyer analysis revealed that HGF –1652 TT carriers had a higher probability of developing ESLD than did CT or CC carriers. The HGF promoter carrying the HGF –1652 T allele had lower transcription activity than did the promoter carrying the C allele. EMSA showed the presence of a potential negative transcription regulator that binds specifically to the HGF promoter carrying a T allele at position –1652. Finally, TT carriers had a relative inability to increase circulating HGF levels even in the presence of advanced interstitial lung disease.

Conclusion

A SNP in the HGF promoter region may modulate the severity of interstitial lung disease by controlling the transcriptional efficiency of the HGF gene.
Coping with complexity: Machine learning optimization of cell‐free protein synthesis
Authors: Caschera Filippo , Bedau Mark A. , Buchanan Andrew , Cawse James , de Lucrezia Davide , Gazzola Gianluca , Hanczyc Martin M. , Packard Norman H.
Published: April 2011

Biological systems contain complex metabolic pathways with many nonlinearities and synergies that make them difficult to predict from first principles. Protein synthesis is a canonical example of such a pathway. Here we show how cell‐free protein synthesis may be improved through a series of iterated high‐throughput experiments guided by a machine‐learning algorithm implementing a form of evolutionary design of experiments (Evo‐DoE). The algorithm predicts fruitful experiments from statistical models of the previous experimental results, combined with stochastic exploration of the experimental space. The desired experimental response, or evolutionary fitness, was defined as the yield of the target product, and new experimental conditions were discovered to have ∼350% greater yield than the standard. An analysis of the best experimental conditions discovered indicates that there are two distinct classes of kinetics, thus showing how our evolutionary design of experiments is capable of significant innovation, as well as gradual improvement. Biotechnol. Bioeng. 2011;108:2218–2228. © 2011 Wiley Periodicals, Inc.
Adaptive generalised predictive control of high purity internal thermally coupled distillation column
Authors: Liu Xinggao , Wang Chengyu , Cong Lin , Ding Feng
Published: April 2011

Internal thermally coupled distillation column (ITCDIC) is a frontier in the energy‐saving distillation researches. One of the bottlenecks to prevent the column from being commercialised is the difficulty in control design due to the high sensitivity to disturbances, strong asymmetric nonlinearity and inverse response especially under high purity. An adaptive multivariable generalised predictive control (AM‐GPC) strategy of ITCDIC process is proposed to solve the difficulties in high purity. The simulation results of AM‐GPC are compared with single input and single output GPC (S‐GPC), multivariable GPC (M‐GPC), modified IMC (M‐IMC) and traditional PID control in detail. The performances confirm the accuracy and validity of AM‐GPC for the high‐purity ITCDIC process. © 2011 Canadian Society for Chemical Engineering
Efficient multichannel coil data compression: A prospective study for distributed detection in wireless high‐density arrays
Authors: Jutras Jean‐David , Fallone B. Gino , De Zanche Nicola
Published: April 2011

Wireless links have been proposed to connect magnetic resonance (MR) array receiver coils to the rest of the system to eliminate the safety and cross‐talk issues encountered using coaxial cables. Analog transmission methods are unsuited because of limited dynamic range and noise figure; therefore, fully independent individual digital receiver modules must be developed. Limited data rates supported by wireless links restrict the number of coil channels that can be transmitted to well below those of the state‐of‐the‐art high‐density arrays that would benefit the most from wireless technology. Two independent methods of compressing MR data prior to transmission are presented that when combined can readily reduce it to one‐third or less of the original amount with negligible impact on image quality parameters such as artifact power (AP) and signal‐to‐noise ratio (SNR). These conservative results were obtained from arrays of six to 16 channels which is typical of today's clinical systems and show that compression efficiency improves with increasing channel density. Simulated and experimental 2D spiral data acquired from a standard head array at 3 tesla was used to evaluate AP as a function of compression by off‐line processing. Spectral compression reduces the acquired data by up to 45% using dynamic demodulation, filtering and decimation. Dynamic range compression followed by bit‐depth reduction further reduces the data by up to 37.5% without visible image artifacts. Image SNR improves 1–25% at the periphery of the field‐of‐view (FOV) due to spectral compression, while dynamic range compression results in a uniform SNR gain of 4–8% over the whole FOV. © 2011 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 39B: 64–77, 2011
A constant‐volume ventilator and gas recapture system for hyperpolarized gas MRI of mouse and rat lungs
Authors: Nouls John , Fanarjian Manuel , Hedlund Laurence , Driehuys Bastiaan
Published: April 2011

We present a ventilator that enables high‐resolution proton and hyperpolarized gas MR imaging of mice and rats. The design differs from previous approaches by eliminating the need for a custom pneumatic valve located near the trachea. This permits the system to be constructed from off‐the‐shelf components and reduces dead volumes sufficiently to make HP gas MRI feasible in the mouse. The constant‐volume ventilator routinely ventilates mice and rats for period of time up to 6 hrs and maintains reproducible tidal volumes over extended image acquisition periods, as we demonstrate with high‐resolution 3D lung images in the mouse using 1H, 3He and 129Xe. The ventilator is designed to deliver a constant tidal volume regardless of changes in airway resistance, which we demonstrate with 3He MR images acquired during severe broncho‐constriction. While the images reveal clear airway narrowing, the 3He signal intensity remained within ±10% of baseline level. Finally, given the paucity of 3He and the high cost of enriched 129Xe, the ventilator has been designed to enable the recapture of these rare gases and we demonstrate a compact system to compress and store them for subsequent reprocessing. We expect that this constant‐volume ventilator will be readily reproducible by other laboratories, which we facilitate by providing extensive parts lists, detailed wiring diagrams and complete plumbing schematics. © 2011 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 39B: 78–88, 2011
Testing MR image artifacts generated by engineering materials
Authors: Tse Zion Tsz Ho , Elhawary Haytham , Montesinos CéSar Antonio Fuentes , Rea Marc , Young Ian , Lamperth Michael
Published: April 2011

Background: To develop mechatronic devices that are compatible with the MR environment, suitable materials must be selected, which can be used correctly within the magnetic fields present while not adversely affecting the MR images. Therefore, suitable technology must be sourced commercially or custom developed for use in MR compatible medical devices. Method: To evaluate the impact a particular material has on the MR environment, methods to quantify the interaction between the scanner and the object are presented. A total number of 22 materials in different geometric configurations were tested using standardized protocols to quantify the artifacts they produced on the MR image of a phantom. Results: The quantification of image artifacts generated are shown, with the materials selected based on their susceptibility, cost and machinability. A simple design methodology for material selection was devised from the test results, which provides systematic guidelines for engineers and researchers to select suitable materials for use inside an MRI scanner, depending on requirements of rigidity and location of the object inside the scanner room. Conclusion: A thorough image artifact examination of 22 commonly‐used engineering materials has been discussed and a systemic design guideline is presented for selecting materials used in MR compatible devices. © 2011 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 39B: 109–117, 2011
A NOS1 variant implicated in cognitive performance influences evoked neural responses during a high density EEG study of early visual perception
Authors: O'Donoghue Therese , Morris Derek W. , Fahey Ciara , Costa Andreia Da , Foxe John J. , Hoerold Doreen , Tropea Daniela , Gill Michael , Corvin Aiden , Donohoe Gary
Published: April 2011

Background: The nitric oxide synthasase‐1 gene (NOS1) has been implicated in mental disorders including schizophrenia and variation in cognition. The NOS1 variant rs6490121 identified in a genome wide association study of schizophrenia has recently been associated with variation in general intelligence and working memory in both patients and healthy participants. Whether this variant is also associated with variation in early sensory processing remains unclear. Methods: We investigated differences in the P1 visual evoked potential in a high density EEG study of 54 healthy participants. Given both NOS1's association with cognition and recent evidence that cognitive performance and P1 response are correlated, we investigated whether NOS1's effect on P1 response was independent of its effects on cognition using CANTAB's spatial working memory (SWM) task. Results: We found that carriers of the previously identified risk “G” allele showed significantly lower P1 responses than non‐carriers. We also found that while P1 response and SWM performance were correlated, NOS1 continued to explain a significant proportion of variation in P1 response even when its effects on cognition were accounted for. Conclusion: The schizophrenia implicated NOS1 variants rs6490121 influences visual sensory processing as measured by the P1 response, either as part of the gene's pleiotropic effects on multiple aspects of brain function, or because of a primary influence on sensory processing that mediates the effects already seen in higher cognitive processes. Hum Brain Mapp, 2011. © 2011 Wiley‐Liss, Inc.
Endpoints and clinical trial design for nonalcoholic steatohepatitis
Authors: Sanyal Arun J. , Brunt Elizabeth M. , Kleiner David E. , Kowdley Kris V. , Chalasani Naga , Lavine Joel E. , Ratziu Vlad , McCullough Arthur
Published: April 2011

Abstract:

Nonalcoholic fatty liver disease is a common cause of chronic liver disease in the general population. Nonalcoholic steatohepatitis (NASH), the aggressive form of nonalcoholic fatty liver disease, is associated with an increased risk of liver-related mortality and cardiovascular disease. At present, a liver biopsy is the only generally acceptable method for the diagnosis of NASH and assessment of its progression toward cirrhosis. Although several treatments have shown evidence of efficacy in clinical trials of varying design, there are no approved treatments for NASH, and published trials are often too divergent to allow meaningful comparisons. There is thus a lack of established noninvasive, point-of-care diagnostics and approved treatment on one hand and a substantial population burden of disease on the other. These provide the rationale for developing consensus on key endpoints and clinical trial design for NASH. Conclusion: This article summarizes the consensus arrived at a meeting of the American Association for the Study of Liver Diseases on the key endpoints and specific trial design issues that are germane for development of diagnostic biomarkers and treatment trials for NASH. (HEPATOLOGY 2011;)
Long-term propagation of serum hepatitis C virus (HCV) with production of enveloped HCV particles in human HepaRG hepatocytes
Authors: Ndongo-Thiam Ndiémé , Berthillon Pascale , Errazuriz Elisabeth , Bordes Isabelle , De Sequeira Sylvie , Trépo Christian , Petit Marie-Anne
Published: April 2011

HepaRG human liver progenitor cells exhibit morphology and functionality of adult hepatocytes. We investigated the susceptibility of HepaRG hepatocytes to

in vitro

infection with serum-derived hepatitis C virus (HCV) particles (HCVsp) and the potential neutralizing activity of the E1E2-specific monoclonal antibody (mAb) D32.10. The infection was performed using HCVsp when the cells actively divided at day 3 postplating. HCV RNA, E1E2, and core antigens were quantified in HCV particles recovered from culture supernatants of differentiated cells for up to 66 days. The density distributions of particles were analyzed on iodixanol or sucrose gradients. Electron microscopy (EM) and immune-EM studies were performed for ultrastructural analysis of cells and localization of HCV E1E2 proteins in thin sections. HCV infection of HepaRG cells was documented by increasing production of E1E2-core-RNA(+) HCV particles from day 21 to day 63. Infectious particles sedimented between 1.06 and 1.12 g/mL in iodixanol gradients. E1E2 and core antigens were expressed in 50% of HCV-infected cells at day 31. The D32.10 mAb strongly inhibited HCV RNA production in HepaRG culture supernatants. Infected HepaRG cells frozen at day 56 were reseeded at low density. After only 1-3 subcultures and induction of a cell differentiation process the HepaRG cells produced high titer HCV RNA and thus showed to be sustainably infected. Apolipoprotein B-associated empty E1E2 and complete HCV particles were secreted. Characteristic virus-induced intracellular membrane changes and E1E2 protein-association to vesicles were observed.

Conclusion:

HepaRG progenitor cells permit HCVsp infection. Differentiated HepaRG cells support long-term production of infectious lipoprotein-associated enveloped HCV particles. The E1E2-specific D32.10 mAb neutralizes the infection and this cellular model could be used as a surrogate infection system for the screening of entry inhibitors. (Hepatology 2011;)
Outcome assessment from the perspective of psychological science: The TAIM approach
Authors: Steinke Pamela , Fitch Peggy
Published: April 2011

This chapter outlines a systematic process for developing assessment measures for complex outcomes that is based on a rigorous research approach used by psychologists.
Developing and assessing college student teamwork skills
Authors: Hughes Richard L. , Jones Steven K.
Published: April 2011

This chapter describes research on team member contributions to overall team effectiveness, and various applications of this research to developing and assessing teamwork by students on team and group projects and assignments.
Automated RNA tertiary structure prediction from secondary structure and low‐resolution restraints
Authors: Seetin Matthew G. , Mathews David H.
Published: April 2011

A novel protocol for all‐atom RNA tertiary structure prediction is presented that uses restrained molecular mechanics and simulated annealing. The restraints are from secondary structure, covariation analysis, coaxial stacking predictions for helices in junctions, and, when available, cross‐linking data. Results are demonstrated on the Alu domain of the mammalian signal recognition particle RNA, the Saccharomyces cerevisiae phenylalanine tRNA, the hammerhead ribozyme, the hepatitis C virus internal ribosomal entry site, and the P4–P6 domain of the Tetrahymena thermophila group I intron. The predicted structure is selected from a pool of decoy structures with a score that maximizes radius of gyration and base–base contacts, which was empirically found to select higher quality decoys. This simple ab initio approach is sufficient to make good predictions of the structure of RNAs compared to current crystal structures using both root mean square deviation and the accuracy of base–base contacts. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Reexperiencing symptoms and the interpersonal‐psychological theory of suicidal behavior among deployed service members evaluated for traumatic brain injury
Authors: Bryan Craig , Anestis Michael
Published: April 2011

Recent evidence suggests that military suicide rates now exceed those of the general public. Numerous recent efforts to address this growing concern have focused on the interpersonal psychological theory of suicidal behavior (IPTS). In the current study, we explored the relationships among reexperiencing symptoms of posttraumatic stress disorder and the three components of the IPTS in a sample of deployed military personnel examined for traumatic brain injury. Results indicated that reexperiencing symptoms were directly related to the acquired capability for suicide, but their relationships to perceived burdensomeness and thwarted belongingness were statistically explained by general mental health distress. Results indicate that mental rehearsal of painful and provocative experiences may have an impact on suicide risk. © 2011 Wiley Periodicals, Inc. J Clin Psychol 67:1–10, 2011.
Synthesis, anti‐inflammatory, and anticancer activity evaluation of some heterocyclic amidine and bis‐amidine derivatives
Authors: Sondhi Sham M. , Rani Reshma , Roy Partha , Agrawal S. K. , Saxena A. K.
Published: April 2011

Heterocyclic amidine derivatives of benzothiazole (6a, 6b, 6c), benzimidazole (6d, 6e, 6f), benzoxazole (6g, 6h, 6i), and bis‐amidine derivatives of pyrimidine, (7a, 7b) & triazole (7c, 7d, 7e) ring system have been synthesized by nucleophilic addition reaction. All these compounds were screened for anti‐inflammatory and anticancer activities. At a dose of 50 mg/kg p.o., compounds 6c (39%), 6e (39%), and 6f (39%) exhibited anti‐inflammatory activity comparable to standard drug ibuprofen, which showed 39% activity and compounds 6b, 6e, 7a, and 7c exhibited moderate anticancer activity against cervix (HELA); neuroblastoma (IMR‐32); breast (MCF‐7), leukemia (THP‐1); and cervix (HELA) human cancer cell lines, respectively. J. Heterocyclic Chem., (2011).
Design, synthesis, and cytotoxic activity evaluation of new linear pyranoxanthone aminoderivatives
Authors: Kolokythas George , Daniilides Konstantinos , Pouli Nicole , Marakos Panagiotis , Pratsinis Harris , Kletsas Dimitris
Published: April 2011

With the aim of enlightening some structure‐activity correlation within the pyranoxanthenone series, we have designed and synthesized a number of new 5‐aminosubstituted pyrano[3,2‐b]xanthen‐6‐ones bearing various 12‐substituents. In vitro cytotoxic potencies of the new derivatives toward the murine leukemia L1210 cell line, human colorectal adenocarcinoma (HT‐29), and human uterine sarcoma (MES‐SA and its 100‐fold resistant to doxorubicin variant MES‐SA/Dx5) cell lines, are described and compared with that of reference drugs. Among the studied compounds, those possessing a second aminosubstituted side‐chain exhibit interesting cytotoxic activity against the solid tumor cell lines, and they retain activity against the multidrug resistant MES‐SA/Dx5 subline. Their selective effect on a phase of the cell cycle was evaluated using HT‐29 cells providing evidence that the compounds induce a G0/G1 arrest. J. Heterocyclic Chem., (2011).
Hepatitis B virus (HBV) X gene diversity and evidence of recombination in HBV/HIV co‐infected persons
Authors: Martin Christina M. , Welge Jeffrey A. , Blackard Jason T.
Published: April 2011

The high frequency of mutation during hepatitis B virus (HBV) infection has resulted in 8 genotypes (A–H) with varying effects on disease severity and treatment efficacy. However, analysis of intrapatient HBV diversity is limited, especially during HIV co‐infection. Therefore, a preliminary study was performed to analyze HBV X gene diversity in 17 HBV/HIV co‐infected individuals. Phylogenetic analysis revealed HBV genotype A in 13 individuals (76.5%) or genotype E in 1 individual (5.9%). Additionally, 3 individuals were dually infected with HBV genotypes A and G (17.6%). Overall, higher genetic distance and entropy were observed in the X region and overlapping polymerase (Pol(X)) regions when compared to the PreS, S, and overlapping polymerase (Pol(PS) and Pol(S)) regions analyzed in the same patients as part of a previous study. In addition, multiple viral variants from 2 individuals with dual HBV infection did not group with either genotype A or G by phylogenetic analysis, indicating possible recombination. SimPlot bootscan analysis confirmed recombination breakpoints within the X gene in both individuals. Recombination between HBV genotypes may represent an important evolutionary strategy that enhances overall pathogenic potential and/or alters the downstream effects of the HBV X protein. J. Med. Virol. 83:1142–1150, 2011. © 2011 Wiley‐Liss, Inc.
Vitamin E blended Uhmwpe may have the potential to reduce bacterial adhesive ability
Authors: Banche Giuliana , Bracco Pierangiola , Bistolfi Alessandro , Allizond Valeria , Boffano Michele , Costa Luigi , Cimino Andrea , Cuffini Anna Maria , del Prever Elena Maria Brach
Published: April 2011

Biomaterial‐associated infection (BAI), a clinical problem resulting in septic failure of joint replacement implants, is initiated by bacterial adhesion, often byStaphylococcus epidermidis. Ultra high molecular weight polyethylene (UHMWPE) is a material of choice for joint replacement; reducing the adhesion ofS. epidermidisto the polymer could be a means to decrease infection. We examined the adhesion of two ATCC and one clinical strain ofS. epidermidisto standard polyethylene (PE), vitamin E blended UHMWPE (VE‐PE), and oxidized UHMWPE (OX‐PE) after different incubation times: a significant (p < 0.01) decrease in the adhered staphylococci on VE‐PE and a significantly higher incidence of the dislodged biofilm bacteria on OX‐PE was observed compared with that registered on PE. With attenuated total reflectance (ATR)–FTIR spectroscopy before and after suspension in bacterial medium for 48 h, new absorptions were observed mainly in OX‐PE, indicating adsorption of protein‐like substances on the polymer surface. We hypothesized that the different hydrophilicity of the surfaces with different chemical characteristics influenced protein adsorption and bacterial adhesion. These results may have clinical implications concerning the prevention of septic loosening: the VE‐PE could have the potential to reduceS. epidermidisadhesive ability if the preliminary data observed in these selected strains is further confirmed, as diversity among clinical strains is well known. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29:1662–1667, 2011
Mass spectrometry of G‐quadruplex DNA: Formation, recognition, property, conversion, and conformation
Authors: Yuan Gu , Zhang Qiang , Zhou Jiang , Li Huihui
Published: April 2011

G‐quadruplexes are special secondary structures formed from G‐rich sequences of DNA, and have proven to play important roles in a number of biological systems, including the regulation of gene transcription and translation. The highly distinctive nature of G‐quadruplex structures and their functions suggest that G‐quadruplexes can act as novel targets for drug development. As a highly sensitive analytical tool, mass spectrometry has been widely used for the analysis of G‐quadruplex structures. Electrospray‐ionization mass spectrometry, in particular, has found captivating applications to probe interactions between small molecules and G‐quadruplex DNA. In this review, we will discuss: (1) mass spectrometry probing of the formation, binding affinity, and stoichiometry between G‐quadruplexes and small molecules; (2) stabilization and collision‐dissociation behavior of G‐quadruplex DNA; (3) the exploration of the equilibrium transfer between a G‐quadruplex and duplex DNA; and (4) the ESI‐MS analysis of the conversion of intramolecular and intermolecular G‐quadruplexes. Finally, we will also introduce the application of new techniques in the analysis of G‐quadruplex conformation, such as ion‐mobility and infrared multiphoton‐dissociation mass spectrometry. We believe that, with the new technical developments, mass spectrometry will play an unparalleled role in the analysis of the G‐quadruplex structures. © 2010 Wiley Periodicals, Inc., Mass Spec Rev 30:1121–1142, 2011
Intracellular glutathione content influences the sensitivity of lung cancer cell lines to methylseleninic acid
Authors: Liu Chengfei , Liu Hongyu , Li Ying , Wu Zhihao , Zhu Yu , Wang Ting , Gao Allen C. , Chen Jun , Zhou Qinghua
Published: April 2011

The synthetic selenium compound methylseleninic acid (MSA) is a direct precursor of active methylselenol and appears to be the best candidate for studies on the mechanisms of selenium cancer prevention and therapy in vitro. Reduced glutathione (GSH) is critical to MSA metabolism, in addition to being a protective antioxidant which scavenges reactive oxygen species (ROS) and maintains the stability of intracellular redox status. In this study, we demonstrated that MSA has an anticancer effect in the human lung cancer cell lines L9981 and 95D using growth inhibition detection, cell‐cycle analysis, and apoptosis detection. We examined the role of intracellular GSH content and detected the ROS induced by MSA by fluorescence microscopy, and we used flow cytometry to quantify the ROS induced by pretreatment and co‐treatment with N‐acetylcysteine (NAC) and MSA. We also confirmed oxidative stress in MSA‐induced apoptosis. MSA inhibited lung cancer cell lines L9981 and 95‐D growth significantly, induced cell‐cycle arrest in the G1 phase and induced apoptosis. Compared to the control group, MSA significantly decreased intracellular GSH content in L9981 cells at higher concentrations of MSA (5 and 7.5 µM), while the intracellular GSH level was also dramatically decreased in L9981 cells treated with 5 µM MSA at different time points of 12‐ and 24‐h (decreased to about 50% and 20% of the control, respectively). Pretreatment with either NAC (GSH synthesis precursor) or buthionine sulfoximine (BSO, GSH synthesis inhibitor) in L9981 cells significantly inhibited the anti‐proliferative effect of MSA. MSA induced the generation of ROS, which was significantly reduced by NAC pretreatment. Furthermore, we also confirmed these results in another lung cancer cell line 95‐D. These results suggest that generation of ROS may be essential for the induction of oxidative stress and apoptosis by MSA in L9981 and 95‐D lung cancer cells. The balance between oxidative stress induced by MSA and the antioxidant effect exerted by intracellular GSH content may determine the ultimate outcome after MSA treatment. Mol. Carcinog. © 2011 Wiley Periodicals, Inc.
A high duty factor 35‐GHz pulse compression weather radar and rainfall observation
Authors: Lee Hoon , Kim Yong‐Hoon
Published: April 2011

A new millimeter wavelength vertical weather radar system has been developed. It uses pulse compression technique and has the characteristics of more than half of duty factor with 5 W solid‐state power amplifier. Nonlinear FM waveforms based on Blackmanharris function at transmitter are generated for range sidelobe suppression. We successfully obtained equivalent radar reflectivity and Doppler mean velocity and these were compared with MRR at moderate rain events for the system verification. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26026
New dual‐band bandpass filter design based on slotted ground structures
Authors: Wang Xiao‐Hua , Xue Quan , Man Kim Fung
Published: April 2011

Two dual‐band bandpass filters featuring flexible frequency choice and compact size are proposed using two kinds of resonators.One is based on two pairs of different dimensional slotted ground resonators; another is based on a pair of slotted ground resonators and a microstrip‐stepped impedance resonator. Unlike traditional filters, the harmonics of slotted ground resonators forming the lower passband are tuned to higher frequencies; the resonators forming the lower and upper passband lie at the two sides of signal line, the two passbands can be adjusted to the desired values with expected bandwidth by changing the sizes of the resonators independently. The interactions between them are minor. The proposed filters do not need extra impedance matching network unlike traditional dual‐band filters and with the ground plane efficiently used, they are more compact in structure. Both filters are optimized with jumping genes evolutionary algorithms for multiobjectives, such as low‐insertion loss, suitable bandwidth, and good stopbands. Two optimized bandpass filters were also implemented. Simulation and measurement results are performed to verify their good characteristics. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26028
Enhanced temperature sensitivity of fiber Bragg grating temperature sensor using thermal expansion of copper tube
Authors: Lee Cherl‐Hee , Kim Min‐Kuk , Kim Kwang Tack , Lee Jonghun
Published: April 2011

The temperature sensitivity of fiber Bragg grating (FBG) temperature sensor is enhanced when using a copper tube to jacket of the FBG.Both sides of the FBG are glued with epoxy to cylindrical ferrules tubes that in turn is inserted and glued to a cylindrical copper tube. As the high thermal expansion coefficient of the cylindrical copper tube pulls both sides of the FBG, the temperature sensitivity is improved 3.3‐fold when compared to that of a bare FBG. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26032
Realization of dual band‐notched function for a UWB antenna using hybrid resonators
Authors: He Kai , Sun Bao‐hua , Zhang Fei‐fei , Wang Ya‐fang , Xue Jin‐yuan
Published: April 2011

A dual band‐notched planar ultra‐wideband (UWB) monopole antenna using hybrid resonators is presented in this article. By etching a complementary electric‐LC resonator on the ground plane and a split ring resonator on the regular octagon radiation patch, dual band‐notched characteristics are achieved. Details of the antenna design, the radiation pattern and the measured results of voltage standing wave ratio (VSWR) are given. Experimental results demonstrate that the proposed antenna operates over a UWB frequency range from 2.9 to 12.4 GHz for VSWR < 2 while providing dual band‐stop function in the frequency bands of 3.3–3.6 and 5.2–5.8 GHz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26033
NURBS surfaces modeled locally corrected Nyström method
Authors: Lai Ben , Yuan Hao‐Bo , Liang Chang‐Hong
Published: April 2011

This paper introduce the Nonuniform Rational B‐Spline (NURBS) surfaces to improve the geometric modeling of the Locally Corrected Nyström (LCN) Method.Compared with the interpolation curvilinear quadrilaterals, the NURBS surfaces can approximate the model with higher accuracy and by much less elements. Thus, the size of the elements can be more flexibly chosen to fully exert the efficiency of the LCN method. Numerical results of the radar cross sections (RCS) show the validity of the proposed technique. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26034
Internal mobile phone antenna array for LTE/WWAN and LTE MIMO operations
Authors: Wong Kin‐Lu , Kang Ting‐Wei , Tu Ming‐Fang
Published: April 2011

An antenna array comprising a main antenna for eight‐band LTE/WWAN operation and an auxiliary antenna to combine with the main antenna for LTE MIMO operation in the mobile phone is presented. Both the main and auxiliary antennas are disposed at the bottom edge of the system circuit board of the mobile phone and separated by a protruded ground. The main and auxiliary antennas can respectively fit in two small no‐ground regions of 15 × 30 mm2 and 15 × 20 mm2 on the system circuit board, while the protruded ground in‐between the two antennas has a width of 10 mm for mounting a USB data port. The main antenna covers the 704–960/1710–2690 MHz bands for eight‐band LTE/WWAN operation, and the auxiliary antenna covers the 704–787/2300–2690 MHz bands such that the main and auxiliary antennas together can perform LTE MIMO operation in the LTE700/2300/2500 bands. The proposed antenna array is fabricated and tested. Results are presented and discussed. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26038
All optical half adder/subtractor using dark‐bright soliton conversion control
Authors: Phongsanam P. , Mitatha S. , Teeka C. , Yupapin P.P.
Published: April 2011

We propose a new design of all‐optical circuit using microring and nanoring devices, in which the simultaneous operation of half adder/subtractor arithmetic can be formed by using the dark‐bright soliton conversion control within the system. The input logic “0” and “1” are performed by using dark and bright soliton pulses, respectively. By using the dark‐bright soliton conversion behavior with in the π/2 phase shift device (i.e., an optical coupler), the arithmetic unit can perform simultaneously at the drop‐ and through‐ ports, respectively. In application, the proposed concept can be recognized as a simple and flexible scheme for performing the logic switching system, which can be used for advanced logical system. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26039
Performance enhancement of Salisbury screen absorber using resistively loaded spiral FSS
Authors: Seman F. Che , Cahill R.
Published: April 2011

In this article, we show that the −10 dB reflectivity bandwidth of a Salisbury screen operating at normal incidence is increased by 56% when a lossy spiral shaped frequency selective surface is inserted between the outermost 377 Ω per square resistive sheet and the ground plane. Moreover, this structure exhibits significantly better angular stability and is suitable for suppressing radar backscatter simultaneously in the TE and TM plane. Reflectivity predictions for normal and 40° incidence are shown to be in close agreement with bistatic measured results over the frequency range 5.4–18 GHz. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26040
Design of a 2.5‐GHZ QVCO robust against high frequency substrate noise
Authors: Molina Marc , Gómez Dídac , Aragones Xavier , Mateo Diego , González José Luis
Published: April 2011

This work presents the design procedure followed to obtain a low‐power voltage‐controlled oscillator (VCO) robust against high‐frequency substrate noise, using as a demonstrator a 2.5 GHz VCO with quadrature outputs (QVCO) based on a 5‐GHz LC tank resonant VCO (LC‐VCO) and frequency divider. A simple, intuitive, and easy to handle analytical model is proposed to identify the design parameters that contribute to the performance degradation of LC‐VCOs due to the effect of high frequency substrate noise. The guidelines obtained have been applied in the design of the low‐power QVCO. Finally, the work discusses several trade‐offs that can be used to maximize the immunity of a LC‐VCO against substrate noise. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26043
Triple band RFID reader antenna for handheld applications
Authors: Mobashsher A. T. , Islam M. T. , Misran N.
Published: April 2011

A novel compact microstrip antenna is presented for tri‐band RFID applications.The antenna consisting of a monopole like bent arm with a capacitively coupled small patch, printed on the alternative side of the ground plane, which might be common for multi‐layer reader circuitry. By adjusting the dimension of the bent arm as well as the embedded bent and capacitive coupling, tri‐band antenna has obtained in a small profile. The prototyped antenna shows broad impedance bandwidths (10 dB ≤ return loss) of 17.5, 32.7, and 25.5% accordingly in UHF (902–928MHz), 2.45GHz and 5.8GHz RFID bands with stable radiation characteristics. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26044
Design of a miniaturized microstrip dual‐mode dual‐band bandpass filter
Authors: Wang Jianpeng , Ni Jia , Pan Jie‐Bin , Ge Lei , Guo Yong‐Xin
Published: April 2011

A miniaturized microstrip dual‐mode dual‐band bandpass filter is presented in this article. The filter is constructed by two slow‐wave dual‐mode resonators and two feed lines. To excite dual‐mode response, each dual‐mode resonator is coupled by an L‐shape feed line. To realize multiple transmission zeroes outside the two passbands, parasitic coupling between two feed lines are also introduced. With these considerations, the proposed dual‐mode dual‐band filter has the properties of compact size, high selectivity, and two transmission poles inside each passband. Demonstrator filter is designed and validated with good agreement between the full‐wave electromagnetic simulations and measurements. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26056
Bidirectional transmission of IEEE 802.11G over colorless WDM‐PON employing a reflective semiconductor optical amplifier
Authors: Avó R. , Guerreiro M. , Medeiros M. C. R.
Published: April 2011

This letter assesses the performance transmission of 802.11g signals over a colorless bidirectional wavelength division multiplexed passive optical network employing a reflective semiconductor optical amplifier. Error‐free operation is demonstrated, for a back‐to‐back configuration with at least 8 dB of optical margin. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26058
Ultra wideband terahertz absorbers
Authors: Dubey Ashish , Shami T.C. , Bhasker Rao K. U. , Prabhu S. S.
Published: April 2011

Most of the recent research on electromagnetic absorbers at terahertz (THz) frequencies is focused on metamaterials based absorber, which provides high absorptivity of electromagnetic (em) radiations in narrow frequency band and tailoring of em response of materials. Under this work, we have also attempted the same problem with different approach, i.e., by using combination of different materials in uniform layered configuration system. Result obtained shows em absorption of 10–20 dB in the lower and higher side of measured spectrum and high absorption of 20–30 dB in central part, i.e., from 1 to 2 THz. Materials with such broadband absorptivity find numerous military and civilian applications. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26059
An F‐shaped printed monopole antenna for dual‐band RFID and WLAN applications
Authors: Panda Jyoti Ranjan , Kshetrimayum Rakhesh Singh
Published: April 2011

A simple microstrip fed printed monopole antenna for the radio frequency identification (RFID) and wireless local area network (WLAN) is presented.The antenna has two different resonant current paths (forming an F‐shaped structure) that support two resonances at 2.44 and 5.18 GHz, which are reserved for RFID and WLAN applications, respectively. Effectively omnidirectional radiation pattern and large impedance bandwidth has been observed both from simulation and experimental results. Impedance bandwidth for center frequency of 2.44 and 5.18 GHz are 0.65 GHz (2.12–2.77 GHz) and 0.59 GHz (4.91–5.50 GHz), respectively. The proposed antenna is simple in design and compact in size; providing broadband impedance matching, consistent omnidirectional radiation patterns and appropriate gain characteristics (>1.5dBi) in the RFID and WLAN frequency regions. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26060