bluuebunny/crossref_metadata_2025 huggingface dataset:
Abdominal Tuberculosis: A Histopathological Study with Special Reference to Intestinal Perforation and Mesenteric Vasculopathy
Authors: Dasgupta Alakananda , Singh Navjeevan , Bhatia Arati
Published: February 2010

Background: Along with the increased incidence of pulmonary tuberculosis in parallel with the increase in population in various parts of the world, in recent years, the incidence of abdominal tuberculosis has also increased. The pathogenetic events in intestinal tuberculosis, which culminate in ulcer formation, perforation, and stricture, still have to be identified.

Aim: To correlate the gross and microscopic features in intestinal tuberculosis, in particular tuberculous perforation with changes in mesenteric vasculature.

Patients and Methods: A one-year prospective study of excised/resected tissues from patients with abdominal tuberculosis requiring surgical intervention was conducted. Tissues from fifty-six patients were included in the study — of which 36 were resected intestinal segments and 20 were intestinal and lymph node biopsies. Hematoxylin and Eosin and Ziehl-Neelsen stains were used for histopathological examination.

Results: Tuberculous enteritis was found to be present in 49 of the 56 patients (87.5%) (ileum being the site most commonly affected), while nodal involvement was seen in 39 (69.6%) patients. Perforations were present in 39 out of 49 (79.6%) intestinal tissues; most being solitary and ileum was the commonest site. Typical epithelioid cell granulomas were seen in the intestine and lymph nodes, with caseation being more prevalent in the latter. The mesenteric vasculature was frequently involved by granulomatous inflammation, with intravascular organizing thrombus being present in 30% of the resected specimens with perforation. Acid fast bacilli were demonstrated in the tissue sections of 37.5% of the patients. AFB positivity was higher in caseating granulomas.

Conclusion: Involvement of mesenteric vasculature by granulomatous inflammation was commonly associated with the ulcerative type with perforation, suggesting that ischemia caused by vascular thrombosis is responsible for tissue breakdown. This implies that vasculitis plays an important role in the natural history of abdominal tuberculosis.
Nonfermenting Gram-Negative Bacilli Infections in a Tertiary Care Hospital in Kolar, Karnataka
Authors: Malini A , Deepa E K , Gokul B N , Prasad S R
Published: February 2010

AIM: Nonfermenting gram-negative bacilli (NFGNB), which are saprophytic in nature, have emerged as important healthcare-associated pathogens. They exhibit resistance not only to beta lactam and the other groups of antibiotics, but also to carbapenems. This study was undertaken to identify the nonfermenters isolated from various clinical samples, to assess their clinical significance, to know the type of healthcare-associated infections they caused, and to know their anti-microbial sensitivity pattern.

Materials and Methods: The nonfermenters were identified using a standard protocol that included tests for motility, oxidase production, oxidation-fermentation test for various sugars, gelatin liquefaction, and growth on 10% lactose agar. The clinical significance was assessed by using various criteria and susceptibility testing was performed with the help of the Kirby-Bauer disc diffusion method.

Results: A total of 193 NFGNB were isolated from 189 clinical specimens. Pseudomonas aeruginosa was the most common nonfermenter, accounting for 53.8%, followed by Acinetobacter baumannii (22.2%), and Pseudomonas fluorescens (10.8%). Other significant NFGNB isolated were: Sphingobacterium species (5.2%), Acinetobacter lwoffii (3.1%), and Stenotrophomonas maltophilia (2.6%). P. aeruginosa showed good sensitivity to imipenem (94%), cefoperazone (70%), amikacin (69%), and ticarcillin (63%). A. baumannii showed 100% sensitivity to imipenem and 70% sensitivity to piperacillin.

Conclusion: P. aeruginosa and A. baumannii were the common NFGNB isolated in our study from patients of, urinary tract infection, bacteremia, surgical site infections, and ventilator associated pneumonia. P. aeruginosa showed good sensitivity to imipenem, amikacin, and cefoperazone while A. baumannii showed good sensitivity to imipenem and piperacillin.
Diagnostic Value of Latex Agglutination in Cryptococcal Meningitis
Authors: Dominic RM Saldanha , Prashanth H V , Shenoy Shalini , Baliga Shrikala
Published: February 2010

Background: Cryptococcus neoformans is the most common fungal pathogen to infect the central nervous system, and an effective diagnostic method is therefore necessary for the early diagnosis of cryptococcal meningitis.

Aim: The efficacy of India ink preparation, cerebrospinal fluid (CSF) culture and CSF cryptococcal antigen detection by the latex agglutination test for diagnosis of cryptococcal meningitis are compared to determine the most efficient test.

Materials and Methods: Two hundred CSF samples from human immunodeficiency virus - positive patients suspected to be suffering from meningitis were screened for Cryptococcus neoformans.

Results: Latex agglutination for cryptococcal antigen detection was found to be more sensitive compared to India ink staining and CSF culture.

Conclusion: Antigen detection by latex agglutination proved to be both sensitive and specific method for the diagnosis of cryptococcal meningitis. Rapid, early diagnosis of infection by detection of cryptococcal antigen by latex agglutination may alter the prognosis for these patients.
Optimum Time to Detection of Bacteria and Yeast Species with BACTEC 9120 Culture System from Blood and Sterile Body Fluids
Authors: Pal Nita , Sharma Rajni , Rishi Suman , Vyas Leela
Published: February 2010

The culture results of 4,807 blood and 383 sterile body fluid specimens received in our laboratory during a 54-month period, were analyzed to determine the time required for culture to become positive, time at which a culture could safely be considered negative, and the spectrum of isolated organisms. The specimens were processed by automated BACTEC 9120 culture system. A total of 1,677 clinically significant microorganisms were isolated. Gram positive and negative bacterial isolation rates were found to be 62.55% and 32.20%, respectively. Yeasts were recovered in 5.24%. False positivity rate was 1.5%. Clinically significant isolates recovered on day four and five were 97.81% and 99.88%, respectively. At day five, the sensitivity was 99.94% and negative predictive value 99.96%. Our data support a five-day incubation protocol for recovery of all clinically significant organisms with sensitivity reduced by 0.06%, when compared with a six-day protocol.
Acinetobacter Septicemia in Neonates Admitted to Intensive Care Units
Authors: Shete Vishal B , Ghadage Dnyaneshwari P , Muley Vrishali A , Bhore Arvind V
Published: February 2010

Background: Acinetobacter species are gaining importance as potential pathogens in neonatal septicemia because of their frequent isolation and multidrug resistance.

Aim and Objectives: The aim of the present study was to evaluate the role of Acinetobacter spp. as important pathogens in neonatal blood stream infection, to identify the associated risk factors, and to evaluate the drug sensitivity pattern.

Materials and Methods: Blood samples of infected neonates were studied bacteriologically. Cases of Acinetobacter septicemia were identified. Speciation of Acinetobacter species was done. Various risk factors were identified. The drug-sensitivity test was done.

Results: A total of 26 Acinetobacter septicemia cases were identified by blood culture. Acb complex strains predominated. Institutional birth and preterm birth were identified as the most frequent significant risk factors. 11.3% mortality rate was recorded. Acb complex strains exhibited a multi-drug resistant pattern. No carbapenem resistance was observed.

Conclusion: Acinetobacter should be added to the list of organisms causing severe nosocomial infection in neonatal intensive care units. Continuous bacteriological surveillance, implementation of infection control policies, careful disinfection of intensive care equipment, and rational antibiotic use are required for control of such infections.
Long-Term Effect of Different Classes of Highly Active Antiretroviral Therapy on Transaminases
Authors: Ikekpeazu Ebele J , Neboh Emeka E , Maduka Ignatius C , Odetunde Odutola , Ifejimalu Uche
Published: February 2010

AIM: The current use of highly active antiretroviral therapy (HAART) for HIV/AIDS patients has increased the recognition of their hepatotoxic effects. The present study is aimed at evaluating the level of aspartate transaminase (AST) and alanine transaminase (ALT) in HIV patients on different classes of HAART, for various durations, which causes its toxicity

Materials and Methods: The AST and ALT levels were estimated in a total of 340 subjects, of which 290 were HIV positive subjects drawn from patients attending the HIV clinic in two Teaching Hospitals, in Nigeria. 240 of the HIV patients were divided into 3 equal groups of 80 each and placed on non-nucleoside reverse transcriptase inhibitors (NNRTI), nucleoside reverse transcriptase inhibitors (NRTI), and protease inhibitors (PI), respectively, and were monitored for different periods of time (3, 6, 12, and >12 months). 50 of the HIV patients, yet to be placed on anti-retroviral therapy and 50 apparently healthy HIV-negative subjects served as the positive and negative controls, respectively.

Results: A significant increase in enzyme levels was noted at three and six months in the NNRTI group, and at only three months in the NRTI and PI groups, when compared with the controls. However, increased ALT was observed at six months in those on PI. The increased ALT and AST levels noted in the NNRTI group were significant when compared to those on NRTI and PI over a three- and six-month duration.

Conclusion: Liver enzyme activities were generally raised in the first three months of HAART, and further in the NNRTI group, after which they progressively fell to the normal level, with time. The highest degree was observed with NNRTIbased HAART.
A categorification of quantum $\mathrm{sl}(n)$
Authors: Khovanov Mikhail , Lauda Aaron D.
Published: February 2010

To an arbitrary root datum we associate a 2-category. For root datum corresponding to sl(n) we show that this 2-category categorifies the idempotented form of the quantum enveloping algebra.
Abrupt Morphology Change upon Thermal Annealing in Poly(3‐Hexylthiophene)/Soluble Fullerene Blend Films for Polymer Solar Cells
Authors: Shin Minjung , Kim Hwajeong , Park Jiho , Nam Sungho , Heo Kyuyoung , Ree Moonhor , Ha Chang‐Sik , Kim Youngkyoo
Published: February 2010

The in situ morphology change upon thermal annealing in bulk heterojunction blend films of regioregular poly(3‐hexylthiophene) (P3HT) and 1‐(3‐methoxycarbonyl)‐propyl‐1‐phenyl‐(6,6)C61 (PCBM) is measured by a grazing incidence X‐ray diffraction (GIXD) method using a synchrotron radiation source. The results show that the film morphology—including the size and population of P3HT crystallites—abruptly changes at 140 °C between 5 and 30 min and is then stable up to 120 min. This trend is almost in good agreement with the performance change of polymer solar cells fabricated under the same conditions. The certain morphology change after 5 min annealing at 140 °C is assigned to the on‐going thermal transition of P3HT molecules in the presence of PCBM transition. Field‐emission scanning electron microscopy measurements show that the crack‐like surface of blend films becomes smaller after a very short annealing time, but does not change further with increasing annealing time. These findings indicate that the stability of P3HT:PCBM solar cells cannot be secured by short‐time annealing owing to the unsettled morphology, even though the resulting efficiency is high.
Graphene–Polymer Nanofiber Membrane for Ultrafast Photonics
Authors: Bao Qiaoliang , Zhang Han , Yang Jia‐xiang , Wang Shuai , Tang Ding Yuan , Jose Rajan , Ramakrishna Seeram , Lim Chwee Teck , Loh Kian Ping
Published: February 2010

A freestanding membrane composed of a nanofiber network of a graphene–polymer nanocomposite is fabricated by electrospinning and applied as an optical element in fiber lasers. The functionalization of graphene with conjugated organic molecules provides a handle for improving mechanical and thermal properties as well as tuning the optical properties. A small loading (0.07 wt%) of functionalized graphene enhances the total optical absorption of poly(vinyl acetate) (PVAc) by 10 times. The electrospun graphene–polymer nanocomposites exhibit wideband saturable absorbance for laser pulse shaping, and attain a larger modulation depth and smaller nonsaturable loss than single‐walled carbon nanotubes. The results show that electrospun graphene nanocomposites are promising candidates as practical and efficient photonic materials for the generation of ultrashort pulses in fiber lasers.
Improving the ON/OFF Ratio and Reversibility of Recording by Rational Structural Arrangement of Donor–Acceptor Molecules
Authors: Ma Ying , Cao Xingbo , Li Guo , Wen Yongqiang , Yang Ye , Wang Jingxia , Du Shixuan , Yang Lianming , Gao Hongjun , Song Yanlin
Published: February 2010

Organic molecules with donor–acceptor (D–A) structure are an important type of material for nanoelectronics and molecular electronics. The influence of the electron donor and acceptor units on the electrical function of materials is a worthy topic for the development of high‐performance data storage. In this work, the effect of different D–A structures (namely D–Π–A–Π–D and A–Π–D–Π–A) on the electronic switching properties of triphenylamine‐based molecules is investigated. Devices based on D–Π–A–Π–D molecules exhibit excellent write–read–erase characteristics with a high ON/OFF ratio of up to 106, while that based on A–Π–D–Π–A molecules exhibit irreversible switching behavior with an ON/OFF ratio of about (3.2 × 101)–(1 × 103). Moreover, long retention time of the high conductance state and low threshold voltage are observed for the D–A switching materials. Accordingly, stable and reliable nanoscale data storage is achieved on the thin films of the D–A molecules by scanning tunneling microscopy. The influence of the arrangement of the D and A within the molecular backbone disclosed in this study will be of significance for improving the electronic switching properties (ON/OFF current ratio and reversibility) of new molecular systems, so as to achieve more efficient data storage through appropriate design strategies.
Measurement of Charge‐Density Dependence of Carrier Mobility in an Organic Semiconductor Blend
Authors: Shuttle Christopher G. , Hamilton Richard , Nelson Jenny , O'Regan Brian C. , Durrant James R.
Published: February 2010

Here, a new methodology for analyzing the charge‐density dependence of carrier mobility in organic semiconductors, applicable to the low‐charge‐density regime (1014–1017 cm−3) corresponding to the operation conditions of many organic optoelectronic devices, is reported. For the P3HT/PCBM blend photovoltaic devices studied herein, the hole mobility µ is found to depend on charge density n according to a power law µ(n) ∝ nδ, where δ = 0.35. This dependence is shown to be consistent with an energetic disorder model based upon an exponential tail of localized intra‐band states.
Synthesis and Catalytic Applications of ansa Compounds with Cycloalkyl Moieties as Bridging Units: A Comparative Study
Authors: Capapé Alejandro , Raith Alexander , Herdtweck Eberhardt , Cokoja Mirza , Kühn Fritz E.
Published: February 2010

The molybdenum and tungsten compounds (Mo{η5‐C5H4[CH(CH2)n]‐η1‐CH}(CO)3) and (W{η5‐C5H4[CH(CH2)3]‐η1‐CH}(CO)3) (2a, 3a n=3; 2b, 3b n=4; 2c, 3c n=5; 2d, 3d n=6) were synthesized by reacting the spiro‐bicyclic compounds 1a–d with the complex [M(CO)3(tach)] (M=molybdenum, tungsten; tach=1,3,5‐trimethylhexahydro‐1,3,5‐triazine). NMR spectroscopy, as well as X‐ray diffraction studies, confirm the formation of an intramolecular ansa bridge. The complexes display a good stability in the solid state (stable up to 180 °C under air, as determined by thermogravimetric studies) and are highly active catalysts at room temperature (molybdenum compounds) or above (tungsten compounds) in olefin epoxidation. In the case of cyclooctene as substrate, TOFs up to ca. 11800 h−1 are obtained. Moreover, most of the catalysts described here display a high selectivity in the epoxidation of cis‐ and trans‐stilbene. In addition, the novel complexes were compared with previously synthesized related compounds, at least matching their catalytic performances.
Gold(I)‐Catalyzed One‐Pot Tandem Coupling/Cyclization: An Efficient Synthesis of Pyrrolo‐/Pyrido[2,1‐b]benzo[d][1,3]oxazin‐ 1‐ones
Authors: Zhou Yu , Zhai Yun , Ji Xun , Liu Guannan , Feng Enguang , Ye Deju , Zhao Linxiang , Jiang Hualiang , Liu Hong
Published: February 2010

A highly efficient method has been developed for the one‐pot synthesis of multi‐ring heterocyclic compounds such as pyrrolo‐/pyrido[2,1‐b]benzo[d][1,3]oxazin‐1‐ones from o‐aminobenzyl alcohols via a gold(I)‐catalyzed tandem coupling/cyclization reaction. Significantly, the strategy presents a straightforward and efficient approach to construct novel tricyclic or polycyclic molecular architectures in which two new CN bonds and one CO bond are formed in a one‐pot reaction operation from two simple starting materials. Moreover, a broad spectrum of substrates can participate in the process effectively to produce the desired products in good yields.
Various α‐Oxygen Functionalizations of β‐Dicarbonyl Compounds Mediated by the Hypervalent Iodine(III) Reagent p‐Iodotoluene Difluoride with Different Oxygen‐Containing Nucleophiles
Authors: Yu Jun , Tian Jun , Zhang Chi
Published: February 2010

p‐Iodotoluene difluoride (p‐Tol‐IF2) has been found to be a general reagent for the effective introduction of various oxygen‐containing functionalities including tosyloxy, mesyloxy, acetoxy, phosphoryloxy, methoxy, ethoxy and isopropoxy at the α‐position of β‐dicarbonyl compounds. These transformations can be readily realized by the use of the combined reagent of p‐iodotoluene difluoride and various oxygen‐containing nucleophilic compounds such as p‐toluenesulfonic acid, methanesulfonic acid, acetic acid, diphenyl phosphate, methanol, ethanol and propan‐2‐ol under mild conditions, respectively. And, the in situ generated hypervalent iodine(III) species via ligand exchange between p‐iodotoluene difluoride and the respective oxygen‐containing nucleophiles are believed to be the real oxidizing agents in such transformations.
Synthesis and Application of Polymer‐Supported Chiral Brønsted Acid Organocatalysts
Authors: Rueping Magnus , Sugiono Erli , Steck Alexander , Theissmann Thomas
Published: February 2010

A new methodology for the immobilization of chiral Brønsted acids has been developed. The resulting heterogeneous organocatalysts have been employed in multiple consecutive catalysis cycles in the asymmetric organocatalytic transfer hydrogenation. The new catalyst system can not only be easily recovered from the reaction mixture in a tea‐bag approach but it can also be easily reused in several catalytic cycles without loss of reactivity and selectivity.
Novel‐doped zinc oxide sorbents for low temperature regenerable desulfurization applications
Authors: Yang Hongyun , Tatarchuk Bruce
Published: February 2010

Eight metal oxide sorbents including transition metal doped ZnO/SiO2 sorbents and ZnO/SiO2 were prepared by incipient wetness impregnation for regenerable desulfurization applications at low temperatures (i.e. room temperature). Among them, copper‐doped sorbent (Cu‐ZnO/SiO2) demonstrated the highest saturation sulfur capacity of 0.213 g sulfur/g ZnO (54% of the theoretical capacity), which is twice that of ZnO/SiO2 sorbent. Compared with ZnO/SiO2, Cu‐ZnO/SiO2 demonstrated superior desulfurization performance in a wide temperature range of 20–400°C. Due to the use of porous SiO2 support, Cu‐ZnO/SiO2 is highly regenerable. It can be easily regenerated in air at low temperatures, ca. 300–550°C, which are much lower than the typical regeneration temperatures of commercial ZnO sorbents. Cu‐ZnO/SiO2 maintained its sulfur capacity during 10 cycles of regeneration/sulfidation. © 2010 American Institute of Chemical Engineers AIChE J, 2010
Enantiospecific Stereodivergent Synthesis of trans‐ and cis‐N(2),3‐Dimethyl‐4‐phenyl‐1,2,3,4‐tetrahydroisoquinolines
Authors: Coote Steven J. , Davies Stephen G. , Fletcher Ai M. , Roberts Paul M. , Thomson James E.
Published: February 2010

The acid‐promoted cyclizations of a range of N‐benzylethanolamines (derived from pseudoephedrine or ephedrine) give the corresponding trans‐N(2),3‐dimethyl‐4‐phenyl‐1,2,3,4‐tetrahydroisoquinolines with high levels of diastereoselectivity and in good yields of isolated product. The cyclizations of the corresponding chromium tricarbonyl complexes are rendered completely stereoselective. Acid‐promoted cyclization of N‐(3′,4′‐dimethoxybenzyl)ephedrine and its chromium tricarbonyl complex occur with complementary diastereoselectivities to give trans‐ and cis‐N(2),3‐dimethyl‐4‐phenyl‐6,7‐dimethoxy‐1,2,3,4‐tetrahydro‐isoquinoline, respectively, in >99:1 d.r. The latter is consistent with a “double inversion” mechanism, which involves neighboring group participation by the chromium tricarbonyl moiety followed by rearomatization to give the corresponding cis‐tetrahydroisoquinoline with overall retention of configuration.
Electrografted Poly(N‐mercaptoethyl acrylamide) and Au Nanoparticles‐Based Organic/Inorganic Film: A Platform for the High‐Performance Electrochemical Biosensors
Authors: Li Limiao , Xu Shoujiang , Du Zhifeng , Gao Yanfang , Li Jinghong , Wang Taihong
Published: February 2010

In this study, we describe the use of the combination of eletrografting poly(N‐mercaptoethyl acrylamide) and Au nanoparticles in the construction of high‐performance biosensors. The poly(N‐mercaptoethyl acrylamide) was electrografted onto the glassy carbon electrode surface, which provided a strongly adhering primer film for the stable attachment of Au nanoparticles and horseradish peroxidase (HRP) enzymes. The performances of the biosensors based on the HRP immobilized in the Au/poly(N‐mercaptoethyl acrylamide) composite film were investigated. A couple of redox peaks were obtained, indicating that the Au nanoparticles could facilitate the direct‐electron transfer between HRP and the underlying electrode. The biosensor showed an excellent electrocatalytic activity toward the reduction of hydrogen oxide and long‐term stability, owing to the stable electrografted film and biocompatible Au nanoparticles. Our results demonstrate that the combination of electrografting and Au nanoparticles provides a promising platform for the immobilization of biomolecules and analysis of redox enzymes for their sensing applications.
Accreting white dwarfs as supersoft X‐ray sources
Authors: Kato M.
Published: February 2010

I review various phenomena associated with mass‐accreting white dwarfs (WDs) in the view of supersoft X‐ray sources. When the mass‐accretion rate is low (Ṁacc < a few × 10–7 M⊙yr–1), hydrogen nuclear burning is unstable and nova outbursts occur. A nova is a transient supersoft X‐ray source (SSS) in its later phase which timescale depends strongly on the WD mass. The X‐ray turn on/off time is a good indicator of the WD mass. At an intermediate mass‐accretion rate an accreting WD becomes a persistent SSS with steady hydrogen burning. For a higher mass‐accretion rate, the WD undergoes “accretion wind evolution” in which the WD accretes matter from the equatorial plane and loses mass by optically thick winds from the other directions. Two SSS, namely RX J0513‐6951 and V Sge, are corresponding objects to this accretion wind evolution. We can specify mass increasing WDs from light‐curve analysis based on the optically thick wind theory using multiwavelength observational data including optical, IR, and supersoft X‐rays. Mass estimates of individual objects give important information for the binary evolution scenario of type Ia supernovae (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Non‐LTE model atmospheres for supersoft X‐ray sources
Authors: Rauch T. , Werner K.
Published: February 2010

In the last decade, X‐ray observations of hot stellar objects became available with unprecedented resolution and S/N ratio. For an adequate interpretation, fully metal‐line blanketed Non‐LTE model‐atmospheres are necessary. The Tübingen Non‐LTE Model Atmosphere Package (TMAP) can calculate such model atmospheres at a high level of sophistication. Although TMAP is not especially designed for the calculation of spectral energy distributions (SEDs) at extreme photospheric parameters, it can be employed for the spectral analysis ofburst spectra of novae like V4743 Sgr or line identifications in observations of neutron stars with low magnetic fields in low‐mass X‐ray binaries (LMXBs) like EXO 0748‐676 (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
X‐ray energy spectra of CAL87
Authors: Ebisawa K. , Rauch T. , Takei D.
Published: February 2010

We present X‐ray spectral analysis of the super‐soft source CAL87 using ASCA, Chandra, XMM‐Newton observations. Early ASCA CCD spectrum reported a strong oxygen absorption edge, which is considered to originate in the an optically thick white‐dwarf atmosphere. On the other hand, contemporaneous grating observations by Chandra and XMM‐Newton indicate emission line dominated spectra, which obviously indicate the optically thin origin. Fitting all the available CCD (ASCA and XMM‐Newton) and grating spectra (XMM‐Newton and Chandra) simultaneously, we show that the CAL87 X‐ray energy spectrum is in fact composed of both an optically thick component with deep absorption edges and an optically thin component with numerous emission lines. The current result supports the standard SSS model that the primary source of X‐ray emission is nuclear burning in the white dwarf atmosphere, surrounded by a highly photoionised, optically thin corona (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Swift observations of CSS081007:030559+054715
Authors: Beardmore A.P. , Osborne J.P. , Page K.L. , Schwarz G. , Starrfield S. , Hakala P. , Ness J.‐U. , Balman S. , Wagner R.M.
Published: February 2010

CSS081007:030559+054715 was discovered by the Catalina Real‐time Transient Survey. Optical spectroscopy revealed a multi‐peaked Hα emission line profile with radial velocities exceeding 1500 km/s, as well as strong Ne emission, suggestive of a neon nova. We monitored the source extensively with the Swift satellite, obtaining a unique dataset spanning 270 days in the soft X‐ray and UV bands. The data reveal a soft, blackbody‐like spectrum with a temperature around 55 eV (though dependent on the modelling), variable X‐ray and UV light curves with a 1.77 day period in both the X‐ray and UV bands, a longer timescale modulation of ∼ 50 days, followed by a slowly declining trend in the soft X‐ray and UV flux. We highlight the Swift observations and their implications for the SSS nature of this object (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Expanding atmosphere models for SSS spectra of novae
Authors: Rossum D.R. van , Ness J.‐U.
Published: February 2010

Super Soft Source (SSS) spectra are powered by nuclear burning on the surface of a white dwarf. The released energy causes a radiatively‐driven wind that leads to a radially extended atmosphere around the white dwarf. Significant blue shifts in photospheric absorption lines are found in the spectra of novae during their SSS phase, being an evidence of continued mass loss in this phase. We present spherically symmetric PHOENIX models that account for the expansion of the ejecta. A comparison to a plane parallel, hydrostatic atmosphere model demonstrates that the mass loss can have a significant impact on the model spectra. The dynamic model yields less pronounced absorption edges, and harder X‐ray spectra are the result. Therefore, lower effective temperatures are needed to explain the observed spectra. Although both types of models are yet to be fine‐tuned in order to accurately determine best fit parameters, the implications on the chemical abundances are going in opposite directions. With the expanding models the requirement for strong depletion of the crucial elements that cause these edges is now avoidable (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Observational evidence for expansion in the SSS spectra of novae
Authors: Ness J.‐U.
Published: February 2010

For several novae, a bright X‐ray source with a spectrum resembling the class of Super Soft X‐ray Sources (SSS) has been observed a few weeks to months after outburst. Novae are powered by explosive nuclear burning on the surface of a white dwarf, and enough energy is produced to power a radiatively driven wind. Owing to the evolution of the opacity of the ejecta, the observable spectrum gradually shifts from optical to soft X‐rays (SSS phase). It has sometimes been assumed that at the beginning of the SSS phase no more mass loss occurs. However, high‐resolution X‐ray spectra of some novae have shown highly blue‐shifted absorption lines, indicating a significant expansion. In this paper, I show that all novae that have been observed with X‐ray gratings during their SSS phase show significant blue shifts. I argue that all models that attempt to explain the X‐ray bright SSS phase have to accommodate the continued expansion of the ejecta (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Recent discoveries of supersoft X‐ray sources in M 31
Authors: Henze M. , Pietsch W. , Haberl F. , Sala G. , Hernanz M. , Hatzidimitriou D. , Rau A. , Hartmann D.H. , Greiner J. , Orio M. , Stiele H. , Freyberg M.J.
Published: February 2010

Classical novae (CNe) have recently been reported to represent the major class of supersoft X‐ray sources (SSSs) in the central area of our neighbouring galaxy M 31. This paper presents a review of results from recent X‐ray observations of M 31 with XMM‐Newton and Chandra. We carried out a dedicated optical and X‐ray monitoring program of CNe and SSSs in the central area ofM 31. We discovered the first SSSs in M 31 globular clusters (GCs) and their connection to the very first discovered CN in a M 31 GC. This result may have an impact on the CN rate in GCs. Furthermore, in our optical and X‐ray monitoring data we discovered the CN M3 1N 2007‐11a, which shows a very short SSS phase of 29–52 days. Short SSS states (durations ≤ 100 days) of CNe indicate massive white dwarfs (WDs) that are candidate progenitors of supernovae type Ia. In the case of M31N 2007‐11a, the optical and X‐ray light curves suggest a binary containing a WD withMWD> 1.0 M⊙. Finally, we present the discovery of the SSS counterpart of the CN M31N 2006‐04a. The X‐ray light curve of M31N 2006‐04a shows short‐time variability, which might indicate an orbital period of about 2 hours (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Populations of supersoft X‐ray sources: Novae, tidal disruption, Type Ia supernovae, accretion‐induced collapse, ionization, and intermediatemass black holes?
Authors: Stefano R. Di , Primini F.A. , Liu J. , Kong A. , Patel B.
Published: February 2010

Observations of hundreds of supersoft X‐ray sources (SSSs) in external galaxies have shed light on the diversity of the class and on the natures of the sources. SSSs are linked to the physics of Type Ia supernovae and accretion‐induced collapse, ultraluminous X‐ray sources and black holes, the ionization of the interstellar medium, and tidal disruption by supermassive black holes. The class of SSSs has an extension to higher luminosities: ultraluminous SSSs have luminosities above 1039 erg s–1. There is also an extension to higher energies: quasisoft X‐ray sources (QSSs) emit photons with energies above 1 keV, but few or none with energies above 2 keV. Finally, a significant fraction of the SSSs found in external galaxies switch states between observations, becoming either quasisoft or hard. For many systems “supersoft” refers to a temporary state; SSSs are sources, possibly including a variety of fundamentally different system types, that pass through such a state. We review those results derived from extragalactic data and related theoretical work that are most surprising and that suggest directions for future research (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Supersoft sources in M31: Comparing the XMM‐Newton deep survey, ROSAT and Chandra catalogues
Authors: Stiele H. , Pietsch W. , Haberl F. , Burwitz V. , Hatzidimitriou D. , Greiner J.
Published: February 2010

To investigate the transient nature of supersoft sources (SSSs) in M 31, we compared SSS candidates ofthe XMM‐Newton Deep Survey, ROSAT PSPC surveys and the Chandra catalogues in the same field. We found 40 SSSs in the XMM‐Newton observations. While 12 of the XMM‐Newton sources were brighter than the limiting flux of the ROSAT PSPC survey, only two were detected with ROSAT ∼10 yr earlier. Five correlate with recent optical novae which explains why they were not detected by ROSAT. The remaining 28 XMM‐Newton SSSs have fluxes below the ROSAT detection threshold. Nevertheless we found one correlation with a ROSAT source, which had significantly larger fluxes than during the XMM‐Newton observations. Ten of the XMM‐Newton SSSs were detected by Chandra with <1– ∼6yr between the observations. Five were also classified as SSSs by Chandra. Of the 30 ROSAT SSSs three were confirmed with XMM‐Newton, while for 11 sources other classifications are suggested. Of the remaining 16 sources one correlates with an optical nova. Of the 42 Chandra very‐soft sources five are classified as XMM‐Newton SSSs, while for 22 we suggest other classifications. Of the remaining 15 sources, nine are classified as transient by Chandra, one of them correlates with an optical nova. These findings underlined the high variability of the sources of this class and the connection between SSSs and optical novae. Only three sources, were detected by all three missions as SSSs. Thus they are visible for more than a decade, despite their variability (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
SSS in young stellar populations and the “prompt” component of Type Ia supernovae
Authors: Nelson T. , Orio M. , Mille F. Di
Published: February 2010

We present the results of a search for UV and optical counterparts of the SSS population in M 31. We find that out of the 56 sources we included in our search, 16 are associated with regions of ongoing or recent star formation. We discuss two particularly interesting sources that are identified optically as early type stars, one of which displayed long term X‐ray evolution similar to that observed in classical novae. We discuss the physical origin of supersoft X‐rays in these and the other SSS in young regions, and their possible link to the so‐called “prompt” component of the Type Ia supernova population (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
On the relation between supersoft X‐ray sources and VY Scl stars: The cases of V504 Cen and VY Scl
Authors: Greiner J. , Schwarz R. , Tappert C. , Mennickent R.E. , Reinsch K. , Sala G.
Published: February 2010

We summarise our optical monitoring program of VY Scl stars with the SMARTS telescopes, and triggered X‐ray as well as optical observations after/during state transitions of V504 Cen and VY Scl (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Supersoft AGNs and their relations to Galactic binaries
Authors: Boller Th.
Published: February 2010

I review some basic results on AGN with supersoft X‐ray spectra and their relations to Galactic binaries in their soft high states. This paper is based on a talk given at the Supersoft Sources Workshop at ESTEC in May 2009. Given the length of the talk and the number of pages the review cannot be complete and is biased towards my personal view. I demonstrate that at high accretion rates supersoft AGNs and Galactic binaries share steep soft X‐ray spectra, that the X‐ray variability of supersoft AGNs is more pronounced compared to Galactic binaries in their high states, that the X‐ray variability of supersoft novae and supersoft AGNs is similar, and that in Galactic binaries mostly positive time lags are seen, while negative time lags are observed in some supersoft AGN (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Oral cleft defects and maternal exposure to ambient air pollutants in New Jersey
Authors: Marshall Elizabeth G. , Harris Gerald , Wartenberg Daniel
Published: February 2010

BACKGROUND

Evidence links exposure to ambient air pollution during pregnancy, particularly gaseous pollutants and particulate matter, to an increased risk of adverse reproductive outcomes though the results for birth defects have been inconsistent.

METHODS

We compared estimated exposure to ambient air pollutants during early pregnancy among mothers of children with oral cleft defects (cases) to that among mothers of controls, adjusting for available risk factors from birth certificates. We obtained ambient air pollutant data from air monitoring sites in New Jersey for carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), sulfur dioxide (SO2), particulate matter <10 μm in aerodynamic diameter (PM10) and particulate matter <2.5 μm in aerodynamic diameter (PM2.5). We used values from the nearest monitor (within 40 km of the residence at birth) for controls, cleft lip with or without cleft palate (CLP) and cleft palate only (CPO).

RESULTS

Based on logistic regression analyses for each contaminant and all contaminants together, there were no consistent elevated associations between selected air pollutants and cleft malformations. Quartile of CO concentration showed a consistent protective association with CPO (p < 0.01). For other contaminants, confidence intervals (95%) of the odds ratios for some quartiles excluded one. CLP showed limited evidence of an association with increasing SO2 exposure while CPO showed weak associations with increasing O3 exposure.

CONCLUSION

There was little consistent evidence associating cleft malformations with maternal exposure to ambient air pollutants. Evaluating particular pollutants or disease subgroups would require more detailed measurement of exposure and classification of cleft defects. Birth Defects Research (Part A), 2010. © 2010 Wiley‐Liss, Inc.
Complete stent dislodgement after successful implantation‐a rare case
Authors: Gan Hwa Wooi , Bhasin Anuj , Wu Chiung‐Jen
Published: February 2010

A successfully deployed stent is normally stable in position and unlikely to be dislodged from the coronary artery. We report a case of complete stent dislodgement after successful implantation in a patient with recent anterior myocardial infarction (AMI). Coronary angulation, a highly calcified coronary artery, an under‐deployed stent, and the process of rewiring contributed to this unexpected event. Fortunately, no unwanted complication occurred as a consequence of this event. © 2010 Wiley‐Liss, Inc.
Detecting Operational Inactivation of Horseradish Peroxidase using an Isoconversional Method
Authors: Puiu M. , Constantinovici M. , Babaligea I. , Raducan A. , Olmazu C. , Oancea D.
Published: February 2010

Kinetic parameters of operational inactivation of horseradish peroxidase during the enzymatic oxidation of 2‐aminophenol with hydrogen peroxide were estimated using an isoconversional method. This method only requires the progress kinetic curves obtained at constant initial concentrations of the substrates. In order to investigate the possible pathways of low‐reactive species compound III formation, a kinetic model was proposed and several rate constants were calculated using an optimization computing program. Generation of an oxygen reactive species in the reaction system was also considered in the reaction scheme. Sensitivity analysis, corroborated with the overall inactivation kinetics observed with the isoconversional method, allows the conclusion that the inactivation of the enzyme occurs mainly via the reaction of compound II with hydrogen peroxide.
Prediction of Layer‐Inversion Behavior of Down‐Flow Binary Solid‐Liquid Fluidized Beds
Authors: Asif M.
Published: February 2010

The layer‐inversion behavior of down‐flow binary solid‐liquid fluidized beds is predicted using the property‐averaging approach. The binary pair in this case consists of a larger solid species which is also heavier than its smaller counterpart, while both are lighter than the fluidizing medium. The model is based on using the generalized Richardson‐Zaki correlation for evaluation of the bed void fraction wherein mean values of particle properties are used. However, unlike the maximum bulk density condition for the conventional up‐flow binary solid fluidized bed, the model is based on a minimum bulk density condition for occurrence of layer inversion. This is due to the fact that the volume contraction phenomenon associated with the mixing of unequal solid species leads to a decrease in bulk density of the bed. Model predictions are also compared using the limited data available in the literature. Predictions are consistent with the observed mixing behavior.
Reducing Energy Consumption and CO2 Emissions in Thermally Coupled Azeotropic Distillation
Authors: Sun L.‐Y. , Chang X.‐W. , Zhang Y.‐M. , Li J. , Li Q.‐S.
Published: February 2010

The design and optimization procedures of a heterogeneous thermally coupled azeotropic distillation sequence with a side stripper (TCADS‐SS) for the purification of isopropanol has been investigated. The proposed procedures can detect the optimal values of the design variables and thereby guarantee the minimum energy consumption, which is related to the minimum CO2 emissions and the lowest total annual cost (TAC). The procedures are applied to the study of the separation of azeotropic mixtures using the two distillation sequences. In the TCADS‐SS, the top end of the side stripper has both liquid and vapor exchange with the main column, which eliminates a condenser in contrast with the conventional heterogeneous azeotropic distillation sequence (CHADS). The results show that not only reductions in energy consumption and CO2 emissions but also higher thermodynamic efficiency can be obtained for the TCADS‐SS.
Development of Soft Sensor for Diesel Fuel Quality Estimation
Authors: Bolf N. , Galinec G. , Baksa T.
Published: February 2010

A soft sensor was developed for quality estimation of diesel fuel as the crude distillation unit product. Due to the stringent fuel quality standards and the growing need to produce various gradations of quality with different feeds, laboratory testing and quality control of the products have become a necessity. On the basis of available continuous temperature measurements and flows of appropriate process streams, software sensors for estimating the cold filter plugging point of diesel fuel were developed. Nonlinear software sensor models were built with the best results achieved by using multilayer neural networks. Statistical data analysis was carried out and the data were critically evaluated. The results showed that soft sensors can be applied for refinery product quality estimation of diesel fuel as an alternative to laboratory testing. So, it becomes possible to continuously estimate fuel quality and to apply methods of inferential control for plant operation optimization.
Model for Calculation of Agglomerate Sizes of Nanoparticles in a Vibro‐fluidized Bed
Authors: Wang H. , Zhou T. , Yang J.‐S. , Wang J.‐J. , Kage H. , Mawatari Y.
Published: February 2010

The behavior of SiO2 nanoparticles and the effects of operating conditions on nanoparticle agglomerate sizes have been investigated under conditions created in a vibro‐fluidized bed (VFB). The experimental results reveal that the vibrations imposed in the bed can suppress slugging and/or channeling, in contrast to conventional fluidization with upflow only. The vibrations imposed in the particle bed affect both the minimum fluidization velocity and the agglomerate size, both of which decrease with increases in the energy introduced to the bed by the vibrations. The effect of vibrations on the agglomeration in vibro‐fluidized beds of nanoparticles depends on the critical vibration frequency corresponding to a minimum agglomerate size. Both the amplitude and the frequency of the applied vibrations have significant effects on the agglomerate size. The experimental results and the consequent analysis reveal that increasing levels of vibrations in the bed yields finer agglomerates. The Richardson‐Zaki scaling law combined with Stokes law permits the prediction of agglomerate sizes and the extent of initial bed voidage. The average agglomerate sizes predicted are in good agreement with those determined experimentally.
CO2 Absorption into Aqueous Solutions of a Polyamine (PZEA), a Sterically Hindered Amine (AMP), and their Blends
Authors: Dubois L. , Kahasha Mbasha P. , Thomas D.
Published: February 2010

Among numerous techniques existing for reducing CO2 emissions, CO2 capture by absorption in aqueous alkanolamine solutions was specifically studied in this work. For the choice of the adequate amine solution, two major criteria must be taken into account: absorption performances (higher with primary and secondary amines) and energy costs for solvent regeneration (more interesting with tertiary and sterically hindered amines). The different types of amines can also be mixed in order to combine the specific advantages of each type of amines, an activation phenomenon being observed. Aqueous solutions of (piperazinyl‐1)‐2‐ethylamine (PZEA, a polyamine known as absorption activator) and 1‐amino‐2‐propanol (AMP, a sterically hindered amine), pure or mixed with other amines, are experimentally compared with respect to CO2 removal performances by means of absorption test runs achieved in a special gas‐liquid contactor at 25 °C. The positive impact of addition of PZEA to monoethanolamine (MEA), N‐methyldiethanolamine (MDEA), and AMP solutions was clearly highlighted. The absorption performances have also been satisfactorily simulated with coherent physicochemical data.
Study of Aromatic Compounds Derived from Sugarcane Bagasse: II. Effect of Concentration
Authors: Al Arni S. , Drake A. F. , Del Borghi M. , Converti A.
Published: February 2010

The results of a set of experiments that were designed to integrate current knowledge on the major constituents of sugarcane bagasse lignin, specifically p‐coumaric, ferulic, syringic acids, and vanillin are presented. These aromatic compounds have well‐known antioxidant power and they are very important for the food, pharmaceutical, and nutraceutical industries. Following a study on the effect of pH upon the spectra of these monomers and the determination of their pKa values, their self‐association properties in ethanol as a solvent, particularly at concentrations < 10–4 M were investigated using UV spectrophotometry and their Kass values were determined. The results collected allowed to better understand the chemistry of sugarcane lignin and provide a contribution to the possible exploitation of this abundant straw material for the recovery of fine chemicals.