bluuebunny/crossref_metadata_2025 huggingface dataset:
SIMULATION AND EXPERIMENTAL RESULTS ON GaN BASED ULTRA-SHORT PLANAR NEGATIVE DIFFERENTIAL CONDUCTIVITY DIODES FOR THz POWER GENERATION
Authors: ASLAN BARBAROS , EASTMAN LESTER F. , DIDUCK QUENTIN
Published: July 2009

A GaN based negative differential conductivity diode utilizing transient ballistic transport effects is proposed and large-signal circuit simulations along with preliminary experimental results are presented. The diode is an n +- n - n + structure and transport is described by an empirical velocity-field relation which is derived directly from femtosecond pulse-probe measurements available in literature and incorporated into the simulations through curve fitting. Efficient THz generation is predicted as a result of ~2.8 peak-to-valley ratio. Pulsed current-voltage characteristics were measured and N -type dependence was observed.
A ROOM TEMPERATURE BALLISTIC DEFLECTION TRANSISTOR FOR HIGH PERFORMANCE APPLICATIONS
Authors: DIDUCK QUENTIN , IRIE HIROSHI , MARGALA MARTIN
Published: July 2009

The Ballistic Deflection Transistor (BDT) is a novel device that is based upon an electron steering and a ballistic deflection effect. Composed of an InGaAs - InAlAs heterostructure on an InP substrate, this material system provides a large mean free path and high mobility to support ballistic transport at room temperature. The planar nature of the device enables a two step lithography process, as well, implies a very low capacitance design. This transistor is unique in that no doping junction or barrier structure is employed. Rather, the transistor utilizes a two-dimensional electron gas (2DEG) to achieve ballistic electron transport in a gated microstructure, combined with asymmetric geometrical deflection. Motivated by reduced transit times, the structure can be operated such that current never stops flowing, but rather is only directed toward one of two output drain terminals. The BDT is unique in that it possesses both a positive and negative transconductance region. Experimental measurements have indicated that the transconductance of the device increases with applied drain-source voltage. DC measurements of prototype devices have verified small signal voltage gains of over 150, with transconductance values from 45 to 130 mS/mm depending upon geometry and bias. Gate-channel separation is currently 80nm, and allows for higher transconductance through scaling. The six terminal device enables a normally differential mode of operation, and provides two drain outputs. These outputs, depending on gate bias, are either complementary or non-complementary. This facilitates a wide variety of circuit design techniques. Given the ultralow capacitive design, initial estimates of ft, for the device fabricated with a 430nm gate width, are over a THz.
MILLIMETER WAVE TO TERAHERTZ IN CMOS
Authors: O K. K. , SANKARAN S. , CAO C. , SEOK E.-Y. , SHIM D. , MAO C. , HAN R.
Published: July 2009

The feasibility of CMOS circuits operating at frequencies in the upper millimeter wave and low sub-millimeter frequency regions has been demonstrated. A 140-GHz fundamental mode VCO in 90-nm CMOS, a 410-GHz push-push VCO in 45-nm CMOS, and a 180-GHz detector circuit in 130-nm CMOS have been demonstrated. With the continued scaling of MOS transistors, 1-THz CMOS circuits will be possible. Though these results are significant, output power of signal generators must be increased and acceptable noise performance of detectors must be achieved in order to demonstrate the applicability of CMOS for implementing practical terahertz systems.
CHARACTERIZATION AND MODELING OF INTEGRATED DIODE IN 1.2kV 4H-SiC VERTICAL POWER MOSFET
Authors: NAIK HARSH , WANG YI , CHOW T. PAUL
Published: July 2009

We have characterized and modeled the integrated diode of a 1.2kV 4 H - SiC power MOSFET. We have measured its static and dynamic characteristics up to 200°C and extracted relevant SPICE model parameters. From the extracted turn-on voltage and ideality factors, we conclude that the integral diode is not a pin junction diode, but a unipolar diode.
ELECTROSTATIC DISCHARGE EFFECT ON TMR RECORDING HEAD: A FLEX ON SUSPENSION CAPACITANCE APPROACH
Authors: JUTONG NUTTACHAI , SIRITARATIWAT APIRAT , SOMPONGSE DUANGPORN , RAKPONGSIRI PORNCHAI
Published: July 2009

Electrostatic discharge (ESD) effects on GMR recording heads have been reported as the major cause of head failure. Since the information density in hard-disk drives has dramatically increased, the GMR head will be no longer in use. The tunneling magnetoresistive (TMR) read heads are initially introduced for a 100 Gbit/in2 density or more. Though the failure mechanism of ESD in GMR recording heads has not been explicitly understood in detail, a study to protect from this effect has to be done. As the TMR head has been commercially started, the ESD effect must be considered. This is the first time that the TMR equivalent circuit has been reported in order to evaluate the ESD effect. A standard human body model (HBM) is discharged across R+ and R- where the capacitances of flex on suspension (FOS) are varied. It is intriguingly found that the electrical characteristics of the TMR head during the discharge period depend on the discharge position. This may be explained in terms of the asymmetry impedance of TMR by using adapted Thevenin's theory. The effect of FOS components on TMR recording heads is also discussed.
LOW LOSS DIELECTRIC MATERIALS FOR HIGH FREQUENCY APPLICATIONS
Authors: JACOB MOHAN V.
Published: July 2009

The microwave properties of some of the low cost materials which can be used in high frequency applications with low transmission losses are investigated in this paper. One of the most accurate microwave characterization techniques, Split Post Dielectric Resonator technique (SPDR) is used for the experimental investigation. The dielectric constants of the 3 materials scrutinized at room temperature and at 10K are 3.65, 2.42, 3.61 and 3.58, 2.48, 3.59 respectively. The corresponding loss tangent values are 0.00370, 0.0015, 0.0042 and 0.0025, 0.0009, 0.0025. The high frequency transmission losses are comparable with many of the conventional materials used in low temperature electronics and hence these materials could be implemented in such applications.
Preclinical photodynamic therapy in Spain 2: Liposome vectorization of photosensitizers; Different strategies, different outcomes
Authors: Mora Margarita , Sagristá M. Lluïsa
Published: July 2009

Photodynamic therapy is an emerging modality of cancer treatment based on the use of photosensitizing drugs, which accumulate selectively in tumor cells. Exposure to visible light induces local cytotoxic effects that lead selectively to tumor cell death in the irradiated region, thereby minimizing the risk and extension of unwanted secondary effects. One of the goals sought in the development of photodynamic therapy drugs is the selective targeting of tumor cells. As a general trend, the indiscriminate delivery of drugs is being increasingly substituted by the selective delivery to pathological tissues which can be achieved by embedding them into transporters that actively recognize differential factors of tumor cells and tissues as compared to healthy ones. Likewise, the chemical modification of the photosensitizers is a valid strategy to change the subcellular localization of the drug. The use of liposomes as transporters for targeted delivery of drugs has attracted particular attention during the last two decades. After a period characterized by the skepticism expressed by certain scientists in the field of drug delivery, interest in liposomes was rejuvenated by the introduction of fresh ideas from membrane biophysics.
SWNT ensembles with porphyrins and phthalocyanines: new architectures for energy conversion
Authors: de la Torre Gema
Published: July 2009

This paper presents the work developed in Spain, in collaboration with other European groups, on the synthesis and photovoltaic applications of hybrid systems comprised of single-walled nanotubes linked to either phthalocyanine or porphyrin moieties.
Higher‐Order Approximate Periodic Solutions of a Nonlinear Oscillator with Discontinuity by Variational Approach
Authors: Orhan Kaya M. , Altay Demirbağ S. , Özen Zengin F.
Published: July 2009

He′s variational approach is modified for nonlinear oscillator with discontinuity for which the elastic force term is proportional to sgn(u). Three levels of approximation have been used. We obtained 1.6% relative error for the first approximate period, 0.3% relative
error for the second‐order approximate period. The third approximate solution has the accuracy as high as 0.1%.
The Survival of Donor-Derived Cells in a Successfully Grafted Corneal Button 10 Years after Penetrating Keratoplasty for Lattice Dystrophy
Authors: Kim Sun Woong , Lee Hwan Young , Kim Tae-im , Shin Kyoung-Jin , Yang Woo Ick , Kim Eung Kweon
Published: July 2009

Aims: To investigate the survival of donor-derived cells in a successfully grafted corneal button 10 years after penetrating keratoplasty for lattice dystrophy. Methods: In 1996, a 48-year-old male with lattice corneal dystrophy underwent penetrating keratoplasty 3 times in the right eye within a 3-month interval. Nine years and 7 months later, the patient underwent a fourth penetrating keratoplasty. After surgery, the previous graft was analyzed to determine the origin of the cells. The epithelium and endothelium were removed, and then the button was dissected into 5 stromal blocks measuring 2 × 1.8 mm. Tissues underwent forensic genotyping using 16 markers (amelogenin for sex chromosomes and 15 autosomal short tandem repeats). Patient buccal tissue DNA was used as a control. Results: The epithelium and buccal tissue contained identical DNA (i.e. recipient DNA). Similarly, the most peripheral stromal tissue contained only recipient DNA. In contrast, the most central stromal tissue only contained DNA of nonrecipient origin (presumably donor), while the stromal tissue between the periphery and center contained both recipient and nonrecipient DNA. Conclusions: The corneal stroma was infiltrated by surrounding recipient-derived keratocytes from the periphery. Therefore, more donor-derived cells had survived in the central stroma.
The Phenomenological Model of Psychotic Vulnerability and Its Possible Implications for Psychological Interventions in the Ultra-High Risk (‘Prodromal’) Population
Authors: Nelson Barnaby , Sass Louis A. , Škodlar Borut
Published: July 2009

The early intervention movement for treatment of schizophrenia and other psychotic disorders has extended to include pharmacological and psychological treatment of putatively prodromal (or ‘ultra-high risk’) patients. The psychotherapy that has been trialed to date is cognitive-behaviour therapy (CBT), due to its apparent success with patients with established psychotic disorder and its current popularity as a therapeutic modality. This paper presents phenomenological models of psychotic, particularly schizophrenic, vulnerability, which emphasise a disturbed basic sense of self (ipseity) and intersubjectivity. We argue that these phenomenological models indicate that CBT may not be the most suitable therapy for prodromal patients, and may even be counterproductive. A central element of this argument is that CBT’s emphasis on cognitive reflection and challenging may encourage a core pathological process in these patients (hyper-reflexive awareness). The paper explores alternatives for psychotherapy that emerge from phenomenological accounts of psychosis, while recognising the paradoxical aspects of psychotherapy with these patients. These alternatives include strategies that provide an intersubjective space where patients can evolve a more robust pre-reflective self-awareness (first-person perspective), second-person perspective and experience of trustworthy relationships when encountering others, empathic attunement afforded by the phenomenological approach’s sensitivity to psychotic experience, and strategies that encourage a form of immersion or absorption in present activity, including mindfulness and creative ‘flow’. We also suggest the possible value of combining therapeutic modalities (even ones that may seem contradictory) and of the need to empirically test therapeutic strategies other than CBT in the ultra-high risk population.
New Options in the Treatment of Lipid Disorders in HIV-Infected Patients
Authors: Silva Erika Ferrari Rafael da , Bárbaro Giuseppe
Published: July 2009

Since the introduction of HAART, there was a remarkably change in the natural history of HIV disease, leading to a notable extension of life expectancy, although prolonged metabolic imbalances could significantly act on the longterm prognosis and outcome of HIV-infected persons, and there is an increasing concern about the cardiovascular risk in this population. Current recommendations suggest that HIV-infected perons undergo evaluation and treatment on the basis of the Third National Cholesterol Education Program Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults (NCEP ATP III) guidelines for dyslipidemia, with particular attention to potential drug interactions with antiretroviral agents and maintenance of virologic control of HIV infection. While a hypolipidemic diet and physical activity may certainly improve dyslipidemia, pharmacological treatment becomes indispensable when serum lipid are excessively high for a long time or the patient has a high cardiovascular risk, since the suspension or change of an effective antiretroviral therapy is not recommended. Moreover, the choice of a hypolipidemic drug is often a reason of concern, since expected drug-drug interactions (especially with antiretroviral agents), toxicity, intolerance, effects on concurrent HIV-related disease and decrease patient adherence to multiple pharmacological regimens must be carefully evaluated. Often the lipid goals of patients in this group are not achieved by the therapy recommended in the current lipid guidelines and in this article we describe other possibilities to treat lipid disorders in HIV-infected persons, like rosuvastatin, ezetimibe and fish oil.
Spirometric Screening of Chronic Obstructive Pulmonary Disease in Smokers Presenting to Tertiary Care Centre
Authors: Qazi Hammad Ali , Soomro Jamil Ahmed , Soomro Tahira Kalisar , Soomro Fahmida Akhtar , Rasheed Fahira , Hashmi Anjum
Published: July 2009

Objective: To determine the frequency of Chronic Obstructive Pulmonary Disease (COPD) by spirometric screening in smokers presenting to tertiary care center.Design: This Cross sectional study was carried out at the Medical department, Civil Hospital Hyderabad from April 2006 to September 2006. The main outcome variables were frequency of COPD in smokers, presenting symptoms and proportion of COPD severity classification.Results: The mean age of the clients was 39.77±6.30 years. The main symptoms of the study population were 75 (75%) patients have cough, 53 (53%) have sputum and 34 (34%) have dyspnoea. The spirometric results showed 39 (39%) smokers had study diagnosis of COPD with 19 (19%) had mild,12 (12%) had moderate and 8 (8%) smokers had severe obstruction.Conclusion: The prevalence of COPD in smokers using spirometry in our population is high (39%) as compared to international studies. This showed a great need and desire of screening for COPD in target population of smokers in our setting. Although effectiveness of screening in terms of smoking cessations and delay of progression of COPD should be calculated in order to make it national guideline. Key words: Chronic Obstructive Pulmonary Disease; Screening; Smokers.   doi: 10.3329/jom.v10i2.2811 J MEDICINE 2009; 10 : 40-44
Efficacy of Ketoconazole in Hormone Refractory Prostate Cancer Patients
Authors: Akhtar Parveen Shahida , Chowdhury Riaz Ahmed , Masud Jafar Md
Published: July 2009

Prostate cancer is a common malignancy among males, with the incidence steadily rising over the past years. Patients with small volume metastasis where early chemotherapy is not warranted, in patients with biochemical failure, and in patients who refuse chemotherapy, management remains controversial as there is no universally accepted treatment protocol. Ketoconazole is an antimycotic that inhibits cytochrome P450 enzymes that are required for the synthesis of androgens and other steroids. In addition, in-vitro studies have suggested some direct cytotoxic effects in prostate cancer cell lines. This study aims to describe our experience with ketoconazole treatment for hormone refractory prostate cancer (HRPC) at our centre. Retrospective chart review of HRPC patients given ketoconazole at a private oncology centre in Dhaka from 2005 - 2006 was done. Patients had histologically proven adenocarcinoma of the prostate with rising Prostate Specific Antigen (PSA) despite androgen deprivation therapy (ADT) with orchiectomy, LHRH agonist therapy and antiandrogens. Ketoconazole was given at 200 mg thrice daily. A total of 10 patients with HRPC was treated and evaluated for response and toxicity. Median age was 70 years old.4 (40%) of the 10 patients had a greater than 50% decrease of PSA values. Responses were seen in 66.66% (2/3) of patients with bone-only disease, 20 % (1/5) of patients with bone and soft tissue disease and 1 patient with PSA-only disease. Median duration of response was 6.75 months (range 2-14 months).There were no grade 3 or 4 toxicities. Overall, 5 (50%) patients had toxicity related to ketoconazole. Its good toxicity profile, low cost and ease of administration makes it a viable option to this group of patients specially in our country. Keyword: Prostate cancer, hormone refractory prostate cancer, ketoconazole   doi: 10.3329/jom.v10i2.2814 J MEDICINE 2009; 10 : 52-55
Opthalmoplegic Migrane with Recurrent Sixth Nerve Palsy: A Rare Presentation of Headache in a Young Lady
Authors: Chowdhury Monzurul H , Nur Zannatun , Begum Hosne Ara , Mahbub Md Shahriar , Ahasan HAM Nazmul
Published: July 2009

Migraine is a common presentation of headache but migraine with opthalmoplegia with third nerve palsy is rare and with fourth or sixth nerve palsy is very rare. Although it represents a benign course, duration and severity are variable among the patients. We demonstrated a young lady presenting with right hemicranial headache for 12 days with several episodes of vomiting. She also complained of double vision for 7 days. The headache started from the inner canthus of right eye and gradually spread throughout the right half of head over 2 hours and was throbbing in nature. She also complained of double vision from 5th day after onset of headache. Interestingly, she informed similar types of attack for two episodes in last 1 year which persisted for around 22-25 days each time. On examination, she appeared ill looking with convergent squint on right lateral gaze. Cranial nerves examinations showed all the cranial nerves were intact except right sixth cranial nerve palsy. Laboratory investigations and neuroimaging were normal. Our case fulfilled the International Classification of Headache Disorders (ICHD II) criteria for opthalmoplegic migraine with recurrent six nerve palsy which responded dramatically with prednisolone therapy 1mg/kg/day which also prevented recurrence within 6 months. Keyword: Migraine, Opthalmoplegic migraine, Abducens nerve palsy.   doi: 10.3329/jom.v10i2.2833   J MEDICINE 2009; 10 : 139-141
A Fourteen Years Old Boy with Cholesterol Ester Storage Disease
Authors: Chowdhury Faizul Islum , Kabir Ahmedul , Banik Jayanta , Paul Pinaki , Kamal Mostofa , Parveen Hasna Hena , Mitu Umme Kulsum , Ferdous Rowzatul
Published: July 2009

Cholesterol ester storage disease (CESD) is a rare autosomal recessive disorder resulting from lysosomal acid lipase deficiency and is usually characterized by hepatomegaly and hyperlipidemia. It is diagnosed by liver biopsy which characteristically shows microvesicular steatosis and periportal fibrosis. Here we report a fourteen years old boy who had presented with unexplained hepatomegaly, and hyperlipidemia determined incidentally. He was finally diagnosed as a case of cholesterol ester storage disease by liver biopsy. Though there is yet no specific treatment for CESD; however, the early detection of cases would make the timely control of complications possible. Keyword: Cholesterol Ester Storage Disease, Lysosomal Storage Diseases, Lipidoses    doi: 10.3329/jom.v10i2.2835   J MEDICINE 2009; 10 : 146-148
Potential of ILRIS3D Intensity Data for Planar Surfaces Segmentation
Authors: Wang Chi-Kuei , Lu Yao-Yu
Published: July 2009

Intensity value based point cloud segmentation has received less attention because the intensity value of the terrestrial laser scanner is usually altered by receiving optics/hardware or the internal propriety software, which is unavailable to the end user. We offer a solution by assuming the terrestrial laser scanners are stable and the behavior of the intensity value can be characterized. Then, it is possible to use the intensity value for segmentation by observing its behavior, i.e., intensity value variation, pattern and presence of location of intensity values, etc. In this study, experiment results for characterizing the intensity data of planar surfaces collected by ILRIS3D, a terrestrial laser scanner, are reported. Two intensity formats, grey and raw, are employed by ILRIS3D. It is found from the experiment results that the grey intensity has less variation; hence it is preferable for point cloud segmentation. A warm-up time of approximate 1.5 hours is suggested for more stable intensity data. A segmentation method based on the visual cues of the intensity images sequence, which contains consecutive intensity images, is proposed in order to segment the 3D laser points of ILRIS3D. This method is unique to ILRIS3D data and does not require radiometric calibration.
Examining psychopathic tendencies in adolescence from the perspective of personality theory
Authors: Sadeh Naomi , Verona Edelyn , Javdani Shabnam , Olson Lacy
Published: July 2009

This study sought to clarify the personality correlates of psychopathic tendencies in adolescents using the Antisocial Process Screening Device [APSD; Frick and Hare, 2001] and a youth adapted version of the Multidimensional Personality Questionnaire [Patrick et al., 2009, unpublished]. A combination of self‐ and parent‐reports on the APSD (n=229) revealed that the three‐facet model of psychopathic tendencies in youth was characterized by a similar constellation of personality traits as the psychopathic construct in adulthood [e.g., Hall, Benning and Patrick, 2004]. Specifically, low anxiety and trait aggression characterized the APSD Callous/Unemotional dimension, social dominance and trait aggression characterized the APSD Narcissism dimension, and disinhibition and low harm avoidance characterized the APSD Impulsivity dimension. The results add credence to the hypothesis that personality relationships to psychopathic tendencies emerge from an early age [Lynam, 2002] and dimensions of psychopathy in youth are associated with distinct personality profiles. Aggr. Behav. 35:399–407, 2009. © 2009 Wiley‐Liss, Inc.
Battery Drivable Organic Single‐Crystalline Transistors Based on Surface Grafting Ultrathin Polymer Dielectric
Authors: Li Liqiang , Zhang Yajie , Li Hongxiang , Tang Qingxin , Jiang Lang , Chi Lifeng , Fuchs Harald , Hu Wenping
Published: July 2009

High‐performance and battery drivable organic single‐crystalline transistors with operational voltages ≤ 2.0 V are demonstrated using high‐quality copper phthalocyanine (CuPc) single‐crystalline nanoribbons and ultrathin polymer nanodielectrics. The ultrathin polymer nanodielectric is synthesized by grafting a ca. 10 nm poly(methyl methacrylate) (PMMA) brush on a silicon surface via surface‐initiated atom‐transfer radical polymerization (SI‐ATRP). This surface‐grafted nanodielectric exhibits a large capacitance, excellent insulating property, and good compatibility with organic semiconductors. The realization of a low operational voltage for battery driving at high performance, together with the merits of surface grafting of a nanodielectric, as well as the mechanical flexibility of the organic nanoribbon, suggests a bright future for use of these transistors in low‐cost and flexible circuits.
Predicting seizure control: Cortical excitability and antiepileptic medication
Authors: Badawy Radwa A. B. , Macdonell Richard A. L. , Berkovic Samuel F. , Newton Mark R. , Jackson Graeme D.
Published: July 2009

Objective

Approximately 30% of patients with newly diagnosed epilepsy do not respond to antiepileptic drugs (AEDs), but this is not predictable. We used transcranial magnetic stimulation to determine the effect of AEDs on cortical excitability in patients with epilepsy and correlated this with a successful response to treatment.

Methods

Ninety‐nine drug‐naïve patients with newly diagnosed epilepsy (55 idiopathic generalized epilepsy, 44 focal epilepsy) were evaluated. Motor threshold and cortical excitability on recovery curve analysis were measured before and 4 to 16 weeks after starting medication. After 1 year of treatment, 43 of 55 idiopathic generalized epilepsy and 26 of 44 focal epilepsy patients were seizure free.

Results

A decrease in cortical excitability occurred in the seizure‐free group as indicated by an increase in motor threshold (p< 0.05) and intracortical inhibition on recovery curve analysis, maximum at the 250‐millisecond interstimulus interval (p< 0.01) compared with pretreatment values. These changes were not present in the group with ongoing seizures.

Interpretation

Seizure freedom is marked by a reduction in transcranial magnetic stimulation measures of cortical excitability, evident shortly after beginning therapy. This virtual normalization of cortical excitability occurred regardless of the seizure characteristics or AED used. Failure to show this response to AED treatment may be valuable as an early predictor of pharmacoresistance in individual patients. ANN NEUROL 2010;67:64–73
The study of fluidization fast pyrolysis of straw based on the biomass entrained flow gasification
Authors: Li Dong , Hao Dailin , Guo Qiang , Xiao Ruirui , Chen Xueli
Published: July 2009

Straw is considered to be a kind of low heating value biomass. A new entrained flow gasification process to utilize the straw was proposed and introduced fast pyrolysis as a straw pre‐treatment unit for biomass entrained flow gasification process. This study was focused on the key factors influencing on the pyrolysis products of straw and optimized the pyrolysis condition based on the analysis results to meet the needs for biomass entrained flow gasification. Experiments were carried out at the temperature ranged from 300 to 600°C. Under certain particle size and optimized fluidization flow, the maximum liquid product yield was 43.1% at the temperature of 400°C and the maximum solid product yield was 65.6% at the temperature of 300°C. The characteristics of both liquid and solid products relevant to the gasification applications were analyzed. The results showed that the energy density of the products was far more higher than that of the crude straw. Finally, an optimal pyrolysis condition was proposed, which was considered to be a suitable feedstock solution for the biomass‐slurry entrained flow gasification. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Dynamic simulation of kinetics, heat and mass transfer during hydrogen sorption by LaNi5
Authors: Moustafa Tarek , Mettawee Eman Beallah , Arafa Abeer
Published: July 2009

A two‐dimensional transient heat and mass transfer models have been developed to investigate the dynamic phenomena of hydrogen absorption and desorption in metal hydride bed. LaNi5 has been chosen as the alloy used for hydrogen storage. The numerical simulation has been conducted to simulate the time–space evolution of temperature, fractional conversion, hydrogen pressure and velocity, in addition to metal density. A correlation for the volumetric reaction rate has been deduced. Also, comparisons have been done between various bed geometries and their influence on the average hydrogen desorbed mass. The simulation results showed that heat transfer controls the overall rate of absorption and desorption processes, and because the driving force for the hydrogen flow is the axial pressure difference; the challenge to get optimum bed geometry is in compromising between heat transfer and pressure drop limitations. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Phenol recovery from simulated wastewater using a vertical membrane reactor
Authors: Jhanwar Manoj , Yu Tsung‐His , Wu Ho‐Shing
Published: July 2009

Phenol was recovered from the simulated wastewater in the form of a useful product, allyl phenyl ether, using A‐172 membrane as phase‐transfer catalyst in a batch and a continuous membrane reactor. The effects of temperature, agitation rates and flow rates of aqueous and organic phases, and concentrations of phenol and allyl bromide on the yield of allyl phenyl ether in the organic phase and phenol removal in the aqueous phase after the reaction were studied. Activation energy and turnover number of the reaction were calculated as well. In the batch mode, the phenol concentration in the treated aqueous phase was found to be < 2 ppm, reduced from 5000 ppm, and more than 99% of the phenol was recovered in the form of allyl phenyl ether after reacting for 180 min. In a continuous mode, the phenol concentration can be reduced from 5000 to 100 ppm in the steady state operation of the reactor. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
Rapid Fabrication of Mesoporous Titania Films with Controlled Macroporosity to Improve Photocatalytic Property
Authors: Kimura Tatsuo , Miyamoto Nobuyoshi , Meng Xiangju , Ohji Tatsuki , Kato Kazumi
Published: July 2009

Hierarchically porous titania films were fabricated by dual templating using a triblock copolymer such as Pluronic F127 and polystyrene (PS) beads, affording mesoporous films with controlled macroporosity. The presence of the triblock copolymer in the precursor solutions suppressed a regular accumulation of spherical PS beads, and PS‐derived macropores could be dispersed over the whole mesoporous titania film through rapid fabrication by spin‐coating. Some of the macropores were clustered, but the presence of the large spaces was important for keeping the mesostructure after calcination. Photodegradation of methylene blue (MB) was investigated by using the photoactive anatase films. The photodegradation of MB over the porous anatase films was accelerated by effective diffusion of MB molecules in the PS‐derived macropores, but it was important for improving photocatalytic performance to regulate the balance between the effectiveness of the diffusion in the macropores and the decrease of the surface area from the embedded macropores, as well as the reduction in the transparency of the porous films.
Palladium‐Catalyzed Carbonylation Reactions of Alkenes and Alkynes
Authors: Brennführer Anne , Neumann Helfried , Beller Matthias
Published: July 2009

Palladium‐catalyzed carbonylation reactions of alkenes and alkynes with different nucleophiles have undergone rapid development ever since the seminal work of Reppe back in the 1930s. Nowadays, a plethora of palladium catalysts and various synthetic protocols are available for the synthesis of valuable carboxylic acids and acrylic acids as well as their derivatives. Herein, we summarize the recent catalyst developments and selected organic applications in this area.
Solid Catalysts on the Nanoscale: Design of Complex Morphologies and Pore Structures
Authors: Schmidt Wolfgang
Published: July 2009

Heterogeneous Catalysis is undoubtedly a key technology in modern chemical industry. Nowadays, most processes in chemical production are catalyzed by solid catalysts. It is thus not surprising that researchers worldwide try to improve existing catalysts or to develop completely new ones. The performance of solid catalysts is determined by their composition but to a great extent also by morphological properties. Control of particle shape and pore topology are thus crucial factors for high performance catalysts. Many interesting approaches have been reported in recent years and the present contribution tries to summarize some of them. The choice of materials and preparation procedures is not comprehensive by a long way, but represents a selection of highly interesting approaches, including bottom‐up approaches as well as post‐synthesis modifications.
Thermal NH Bond Activation on Anionic and Cationic Platinum Clusters: Non‐Predetermined Reaction Pathways Indicate Transitions to a Bulk Surface Reactivity
Authors: Ončák Milan , Cao Yali , Höckendorf Robert F. , Beyer Martin K. , Zahradník Rudolf , Schwarz Helmut
Published: July 2009

Reactions of cationic and anionic platinum clusters Ptn+/−, n=1–5, with NH3 are studied by FT‐ICR mass spectrometry and DFT calculations. With cationic clusters, radiative association of an intact NH3 is the dominant reaction channel. On anionic clusters, NH3 undergoes reductive elimination of molecular hydrogen, with nitride and hydride bound at remote sites of the cluster. Nitride assumes a bridge position, while hydride is bound atop a single platinum atom. On the [Ptn,NH3]− potential energy surface, for n=4 fifteen local minima and connecting transition states were identified with relevance to the hydrogen formation reaction, and 12 local minima were identified for n=5. These potential energy surfaces offer a rich variety of pathways, illustrating a key feature of a successful bulk catalyst: The variety of pathways helps the catalyst to work over a wide range of temperatures and pressures.
Generation of similarity knowledge flow for intelligent browsing based on semantic link networks
Authors: Luo Xiangfeng , Xu Zheng , Li Qing , Hu Qingliang , Yu Jie , Tang Xinhuai
Published: July 2009

Similarity Knowledge Flow (SKF) is a kind of scientific workflow, providing an effective technique and theoretical support for intelligent browsing in the Web and e‐Science environment. In this paper, a Semantic Link Networks (SLN) based SKF generation method is proposed. First, the topics are represented by Element Fuzzy Cognitive Maps then the semantic values of concepts/keywords and relations are calculated. Third, semantic similarity degrees between topics are calculated to build SLN‐based semantic values of concepts and their relations in Element Fuzzy Cognitive Maps. In this way, similar relations at the keyword level are extended to the topic level. With the help of SLN and based on user's demand, SKF is generated as the browsing path of topics to guide user browsing behaviors. Finally, the semantic value of SKF is defined as a criterion to evaluate the browsing path of topics. Experimental results show that the browsing path of topics is easy to be activated by SKF which is generated by SLN. The proposed method has been proved to have a very good prospect in the fields of Web services and e‐Science applications. Copyright © 2009 John Wiley & Sons, Ltd.
Exploiting graphical processing units for data‐parallel scientific applications
Authors: Leist A. , Playne D. P. , Hawick K. A.
Published: July 2009

Graphical processing units (GPUs) have recently attracted attention for scientific applications such as particle simulations. This is partially driven by low commodity pricing of GPUs but also by recent toolkit and library developments that make them more accessible to scientific programmers. We discuss the application of GPU programming to two significantly different paradigms—regular mesh field equations with unusual boundary conditions and graph analysis algorithms. The differing optimization techniques required for these two paradigms cover many of the challenges faced when developing GPU applications. We discuss the relevance of these application paradigms to simulation engines and games. GPUs were aimed primarily at the accelerated graphics market but since this is often closely coupled to advanced game products it is interesting to speculate about the future of fully integrated accelerator hardware for both visualization and simulation combined. As well as reporting the speed‐up performance on selected simulation paradigms, we discuss suitable data‐parallel algorithms and present code examples for exploiting GPU features like large numbers of threads and localized texture memory. We find a surprising variation in the performance that can be achieved on GPUs for our applications and discuss how these findings relate to past known effects in parallel computing such as memory speed‐related super‐linear speed up. Copyright © 2009 John Wiley & Sons, Ltd.
An N‐methylpolyvinylpyridinium cationic polymer for capillary coating in electrophoresis of proteins and peptides
Authors: Sebastiano Roberto , Mendieta Martha E. , Contiello Nunzia , Citterio Attilio , Righetti Pier Giorgio
Published: July 2009

A novel cationic polymeric coating is here reported, consisting of a N‐methylpolyvinylpyridinium quaternary ion. This coating, combined with an isoelectric, aspartic acid as BGE, offers excellent separations of low‐ to high‐Mr proteins, of low‐ to high‐pI values, coupled to very high run‐to‐run repeatability. The importance of a hydrophilic coating is also illustrated, whereas the N‐methylpolyvinylpyridinium quaternary ion does not seem to adsorb even a large size protein as human albumin, separations are already distorted in the N‐ethyl derivative and totally ruined in the N‐octyl derivative, due to its high hydrophobicity.
Application of artificial neural networks in the prediction of product distribution in electrophoretically mediated microanalysis
Authors: Riveros Toni Ann , Porcasi Lyra , Muliadi Sarah , Hanrahan Grady , Gomez Frank A.
Published: July 2009

The successful application of artificial neural networks toward the prediction of product distribution in electrophoretically mediated microanalysis is presented. To illustrate this concept, we examined the factors and levels required for optimization of reaction conditions for the conversion of nicotinamide adenine dinucleotide to nicotinamide adenine dinucleotide, reduced form by glucose‐6‐phosphate dehydrogenase in the conversion of glucose‐6‐phosphate to 6‐phosphogluconate. A full factorial experimental design examining the factors voltage, enzyme concentration, and mixing time of reaction was utilized as input‐output data sources for suitable artificial neural networks training for prediction purposes. This approach proved successful in predicting optimal values in a reduced number of experiments. Model validation addressing the extent of reaction and product ratios were subsequently determined experimentally in replicate analyses, with results shown to be in good agreement (<10% discrepancy difference) with predicted data.
CZE for glycoform profiling and quality assessment of recombinant human interleukin‐7
Authors: Alahmad Youssef , Thuy Tran Nguyet , Duboeuf Jérémy , Grégoire Anne , Rancé Iann , Taverna Myriam
Published: July 2009

The aim of the present work was to develop a simple high‐resolution CZE method for glycoform profiling and quality assessment of recombinant human interleukin‐7 (rhIL‐7) produced in Chinese hamster ovary cells. Classical and isoelectric buffers and several monoamines used as alkaline component of BGE at very low concentration have been investigated in order to optimize the resolution. The best separation was achieved using a fused‐silica capillary and a buffer composed of 25 mM citrate/triethanolamine at pH 2.6. Under these acidic conditions, triethanolamine was able to reverse EOF favorably and to limit rhIL‐7 adsorption. This method allowed the separation of four groups of peaks ranging from low to high‐sialylated glycoforms. An extensive study on inter‐run rinsing procedures has been conducted. Rinsing with 50 mM SDS was retained to achieve the optimal repeatability. Excellent intermediate precision was obtained for migration time (RSD<0.6%), while RSD for intraday studies were only less than 2.9%. Satisfactory inter and intraday repeatabilities were also observed for relative peak area. We finally demonstrated that reliable information could be obtained to address comparability studies and demonstrate batch‐to‐batch consistency of biomanufactured rhIL‐7.
A new single‐step quantitative pathogen detection system: Template‐tagging followed by multiplex asymmetric PCR using common primers and CE‐SSCP
Authors: Shin Gi Won , Cho Yang Sook , Hwang Hee Sung , Oh Mi‐Hwa , Nam Hong Gil , Park Jin Hyun , Jung Gyoo Yeol
Published: July 2009

Rapid diagnosis of bacterial infection is important for patient management and appropriate therapy during the early phase of bacteria‐induced disease. Among the existing techniques for identifying microbial, CE‐SSCP combined with 16S ribosomal RNA gene‐specific PCR has the benefits of excellent sensitivity, resolution, and reproducibility. However, even though CE‐SSCP can separate PCR products with high‐resolution, multiplex detection and quantification are complicated by primer‐dimer formation and non‐specific amplification. Here, we describe a novel technique for multiplex detection and quantification of pathogens by template‐tagging followed by multiplex asymmetric PCR and subsequent CE‐SSCP. More specifically, we reverse transcribed 16S ribosomal RNAs from seven septicemia‐inducing pathogens, tagged the templates with common end sequences, and amplified them using common primers. The resulting amplicons could be successfully separated by CE‐SSCP and quantified by comparison to an internal standard. This method yielded results that illustrate the potential of this system for diagnosing infectious disease.
Functional specialization and dynamic resource allocation in visual cortex
Authors: Plomp Gijs , Leeuwen Cees van , Ioannides Andreas A.
Published: July 2009

We studied the spatiotemporal characteristics of cortical activity in early visual areas and the fusiform gyri (FG) by means of magnetoencephalography (MEG). Subjects performed a visual classification task, in which letters and visually similar pseudoletters were presented in different surrounds and under different task demands. The stimuli appeared in a cued half of the visual field (VF). We observed prestimulus effects on amplitudes in V1 and Cuneus relating to VF and task demands, suggesting a combination of active anticipation and specialized routing of activity in visual processing. Amplitudes in the right FG between 150 and 350 ms after stimulus onset reflected task demands, while those in the left FG between 300 and 400 ms showed selectivity for graphemes. The contrasting stimulus‐evoked effects in the right and left FG show that the former area is sensitive to task demands irrespective of stimulus content, whereas the left FG is sensitive to stimulus content irrespectively of task demand. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Variation in TREK1 gene linked to depression‐resistant phenotype is associated with potentiated neural responses to rewards in humans
Authors: Dillon Daniel G. , Bogdan Ryan , Fagerness Jesen , Holmes Avram J. , Perlis Roy H. , Pizzagalli Diego A.
Published: July 2009

The TREK1 gene has been linked to a depression‐resistant phenotype in rodents and antidepressant response in humans, but the neural mechanisms underlying these links are unclear. Because TREK1 is expressed in reward‐related basal ganglia regions, it has been hypothesized that TREK1 genetic variation may be associated with anhedonic symptoms of depression. To investigate whether TREK1 genetic variation influences reward processing, we genotyped healthy individuals (n = 31) who completed a monetary incentive delay task during functional magnetic resonance imaging (fMRI). Three genotypes previously linked to positive antidepressant response were associated with potentiated basal ganglia activity to gains, but did not influence responses to penalties or no change feedback. TREK1 genetic variations did not affect basal ganglia volume, and fMRI group differences were confirmed when accounting for self‐report measures of anhedonia. In addition, the total number of “protective” TREK1 alleles was associated with stronger responses to gains in several other reward‐related regions, including the dorsal anterior cingulate cortex, orbitofrontal cortex, and mesial prefrontal cortex. In control analyses, associations between basal ganglia responses to gains and functional polymorphisms in the dopamine transporter (DAT1) and catechol‐O‐methyltransferase (COMT) genes were also explored. Results revealed that TREK1 and DAT/COMT genotypes were independently related to basal ganglia responses to gains. These findings indicate that TREK1 genotypes are associated with individual differences in reward‐related brain activity. Future studies in depressed samples should evaluate whether variation in neural responses to rewards may contribute to the association between TREK1 and antidepressant response in humans. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.
Sustained inhibition of tumor growth and prolonged survival following sequential administration of doxorubicin and zoledronic acid in a breast cancer model
Authors: Ottewell Penelope D. , Lefley Diane V. , Cross Simon S. , Evans C. Alyson , Coleman Robert E. , Holen Ingunn
Published: July 2009

Combination therapy, using agents that target the microenvironment as well as the cancer cells, is common in the treatment of advanced breast cancer. Here, we show that a 6‐week course of weekly sequential administration of the cytotoxic drug doxorubicin (2 mg/kg), followed 24 hr later by the antiresorptive agent zoledronic acid (100 μg/kg), causes substantial inhibition of subcutaneous MDA‐MB‐436 breast tumor growth in immunocompromised mice, leading to significantly increased survival. Tumor growth did not resume following withdrawal of treatment after 6 weeks, with 60% of the animals in this group surviving for more than 160 days. In comparison, animals receiving single‐agent therapy all died within 50 days. Molecular analysis of the tumors showed no effect on cell cycle or apoptosis following administration of 100 μg/kg zoledronic acid or 2 mg/kg doxorubicin alone. When doxorubicin was administered 24 hr before zoledronic acid, tumors displayed decreased expression of CYCLINS E1, B, D1 and D3 as well as CDK2, CDC2, CDK4 and CDK7, indicative of cell‐cycle inhibition. Tumors from animals receiving sequential treatment also showed induction of both intrinsic‐ and extrinsic‐apoptotic pathways, with increased expression of BAX, decreased expression of BCL‐2 and activation of CASPASE 3, 8 and 9. Accumulation of the unprenylated form of RAP1a, a surrogate marker for uptake of zoledronic acid, was only detected in tumors from animals treated with doxorubicin 24 hr before zoledronic acid. Our data are the first to show a sustained antitumor effectin vivofollowing a limited course of sequential administration of doxorubicin followed by zoledronic acid.