bluuebunny/crossref_metadata_2025_split huggingface dataset:
Highly Efficient Amine Organocatalysts Based on Bispidine for the Asymmetric Michael Addition of Ketones to Nitroolefins
Authors: Yang Zhigang , Liu Jie , Liu Xiaohua , Wang Zhen , Feng Xiaoming , Su Zhishan , Hu Changwei 
Published: August 2008

AbstractA highly diastereoselective and enantioselective Michael addition of cyclohexanone, acetone and other ketones to nitroolefins was developed by the use of an amine organocatalyst based on bispidine. Additionally, a theoretical study of transition structures revealed that this bispidine‐based primary‐secondary amine catalyst could serve through an enamine intermediate and H‐bond interaction, which was important for the reactivity and selectivity of this reaction.
Occupational asthma caused by sculptured nails containing methacrylates
Authors: Sauni Riitta , Kauppi Paula , Alanko Kristiina , Henriks‐Eckerman Maj‐Len , Tuppurainen Matti , Hannu Timo 
Published: August 2008

AbstractBackgroundIn recent decades, the use of artificial nails including methacrylates (MAs) has increased. This study presents the first two clinical cases of occupational asthma (OA) caused by sculptured nails containing MAs.MethodsIn both cases, OA was diagnosed on the basis of a work simulation test combined with the patient's history of occupational exposure and respiratory symptoms.ResultsBoth patients developed work‐related respiratory symptoms 4–5 years before the current examinations. Previously, the first patient (a 30‐year‐old female) was diagnosed as having allergic contact dermatitis (ACD) to MAs; the second patient (a 27‐year‐old female) had no skin symptoms. In both cases, a dual asthmatic reaction was observed in the bronchial provocation test, in which the patients simulated their work using their own products including MAs.ConclusionsSculptured nails containing MAs can induce OA in nail technicians. Products not containing MAs should be used to prevent OA and ACD. If MAs are used, they should be handled with appropriate safety measures. Am. J. Ind. Med. 51:968–974, 2008. © 2008 Wiley‐Liss, Inc.
On estimating the conditional expected shortfall
Authors: Peracchi Franco , Tanase Andrei V. 
Published: August 2008

AbstractUnlike the value at risk, the expected shortfall is a coherent measure of risk. In this paper, we discuss estimation of the expected shortfall of a random variable Yt with special reference to the case when auxiliary information is available in the form of a set of predictors Xt. We consider three classes of estimators of the conditional expected shortfall of Yt given Xt: a class of fully non‐parametric estimators and two classes of analog estimators based, respectively, on the empirical conditional quantile function and the empirical conditional distribution function. We study their sampling properties by means of a set of Monte Carlo experiments and analyze their performance in an empirical application to financial data. Copyright © 2008 John Wiley & Sons, Ltd.
Using the Rasch model to assess a university service on the basis of student opinions
Authors: Aiello Fabio , Capursi Vincenza 
Published: August 2008

AbstractIn this paper we use the Rasch model (RM) as a tool to measure the perceived quality of student services at the Reception Office of an Italian university faculty. This paper has both a substantive and a methodological aim. The former is concerned with measuring the service quality of the Reception Office, while the latter concerns the definition and validation of an instrument for measuring perceived quality. The sample comprised 273 students enrolled at the Faculty of Economics at the University of Palermo (Aiello F. Il modello di Rasch per la costruzione di uno strumento di misura della qualità di un Servizio. Ph.D. Thesis, University of Palermo, Palermo, 2005).The RM is applied to produce specific measurements of the perceived quality for each service feature in order to conduct a critical analysis of the results. We sought to verify some important assumptions and desiderata of the RM: (i) Unidimensionality: in the user's opinion, are the single features of the service ‘good’ at defining the whole construct of global quality? (ii) Targeting: is the range of the measurements provided by the RM for each item able to cover all the possible satisfaction levels required by the students? (iii) Measurement of the perceived quality of each feature: is it possible to rank the items according to their level of perceived quality (which may be a good way of identifying the weaknesses of the service in order to allocate additional resources to make due adjustments)? (iv) Item separation: are the service features (items) redundant with respect to the satisfaction levels required by the students? (v) Differential item functioning: is the item‐difficulty hierarchy invariant across the student factors? In our opinion the last issue was of great interest as it can identify assessment differences. Indeed, there appeared to emerge a different severity of judgment towards the single features of the service from the students, according to their length of stay in the system. Copyright © 2008 John Wiley & Sons, Ltd.
Rotational dynamics of HIV‐1 nucleocapsid protein NCp7 as probed by a spin label attached by peptide synthesis
Authors: Zhang Zhiwen , Xi Xiangmei , Scholes Charles P. , Karim Christine B. 
Published: August 2008

Abstract2,2,6,6‐Tetramethylpiperidine‐1‐oxyl‐4‐amino‐4‐carboxylic acid (TOAC) spin label was attached at the N‐terminal position to interrogate the dynamics of the HIV‐1 nucleocapsid Zn‐finger protein, NCp7. NCp7 is a 6.4‐kDa 55‐mer critical to the recognition, packaging, and efficient reverse transcription of viral RNA that has stem‐loop structures, such as the RNA stem‐loop 3 used in this work. The NCp7, made by solid‐phase peptide synthesis with TOAC incorporated into the α‐carbon backbone at the N‐terminal “0” position, showed analytical purity and biological activity. Electron Paramagnetic Resonance (EPR) spectra of the N‐terminal TOAC indicated rapid temperature‐sensitive motion of the probe (≤0.33 ns correlation time) on the flexible N‐terminal segment. This N‐terminal TOAC‐NCp7 reported a RNA‐NCp7 interaction at a 1:1 ratio of NCp7 to RNA, which caused the tumbling time to be slowed from about 0.3 ns to about 0.5 ns. NCp7 is a largely disordered protein that adapts to its RNA targets. However, as shown by circular dichroism, ≥90% trifluoroethanol [(TFE), an α‐helix enhancer] caused the TOAC‐NCp7 without zinc in its fingers to change to a fully helical conformation, while the TOAC spin label was concurrently reporting a tumbling time of well over a nanosecond, as the N‐terminal TOAC became inflexibly enfolded. Even with TFE present, the existence of intact Zn‐finger regions in NCp7 prevented complete formation of helical structure, as shown by circular dichroism, and decreased the N‐terminal TOAC tumbling time, as shown by EPR. This study demonstrated TOAC at the N‐terminal of NCp7 to be a reporter for the considerable conformational lability of NCp7. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 1125–1135, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Physicochemical properties of blue fluorescent protein determined via molecular dynamics simulation
Authors: Krasnenko Veera , Tkaczyk Alan H. , Tkaczyk Eric R. , Mauring Koit 
Published: August 2008

AbstractBlue fluorescent protein (BFP) is a mutant of green fluorescent protein (GFP), where the chromophore has been modified to shift the emitted fluorescence into the blue spectral region. In this study, MD calculations were performed with the GROMACS simulation package and AMBER force field to investigate the dependence of BFPs physicochemical properties on temperature and applied pressure. The MD approach enabled us to calculate the compressibility of protein itself, separately from the nontrivial contribution of the hydration shell, which is difficult to achieve experimentally. The computed compressibility of BFP (3.94 ×10−5 MPa−1) is in agreement with experimental values of globular proteins. The center‐of‐mass diffusion coefficient of BFP and its dependence on temperature and pressure, which plays an important role in its application as a probe for intracellular liquid viscosity measurement, was calculated and found to be in good agreement with photobleaching recovery experimental data. We have shown that decreased temperature as well as applied pressure increases the water viscosity, but the concomitant decrease of the BFP diffusion coefficient behaves differently from Stokes‐Einstein formula. It is shown that the number of hydrogen bonds around the protein grows with pressure, which explains the aforementioned deviation. Pressure also reduces root mean square (RMS) fluctuations, especially those of the most flexible residues situated in the loops. The analysis of the RMS fluctuations of the backbone Cα atoms also reveals that the most rigid part of BFP is the center of the β‐barrel, in accord with temperature B factors obtained from the Protein Data Bank. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 1136–1143, 2008.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Production of astaxanthin by Haematococcus pluvialis: Taking the one‐step system outdoors
Authors: García‐Malea M. Carmen , Acién F. Gabriel , Del Río Esperanza , Fernández José M. , Cerón M. Carmen , Guerrero Miguel G. , Molina‐Grima Emilio 
Published: August 2008

AbstractThe feasibility of a one‐step method for the continuous production of astaxanthin by the microalga Haematococcus pluvialis has been verified outdoors. To this end, influence of dilution rate, nitrate concentration in the feed medium, and irradiance on the performance of continuous cultures of H. pluvialis was firstly analyzed indoors in bubble column reactors under daylight cycles, and then outdoors, using a tubular photobioreactor. At the laboratory scale, the behavior of the cultures agreed with that previously recorded in continuous illumination experiences, and attested that the major factors determining biomass and astaxanthin productivity were average irradiance and specific nitrate supply. The rate of astaxanthin accumulation was proportional to the average irradiance inside the culture, provided that a nitrate limiting situation had been established. The accumulation of astaxanthin under daylight cycles was maximal for a specific nitrate input of 0.5 mmol/g day. The recorded performance has been modeled on the basis of previously developed equations, and the validity of the model checked under outdoor conditions. Productivity values for biomass and astaxanthin of 0.7 g/L day and 8.0 mg/L day respectively, were obtained in a pilot scale tubular photobioreactor operating under continuous conditions outdoors. The magnitude of the experimental values, which matched those simulated from the obtained model, demonstrate that astaxanthin can be efficiently produced outdoors in continuous mode through a precise dosage of the specific nitrate input, taking also into consideration the average irradiance inside the culture. Biotechnol. Bioeng. 2009;102: 651–657. © 2008 Wiley Periodicals, Inc.
Fabrication of skeletal muscle constructs by topographic activation of cell alignment
Authors: Zhao Yi , Zeng Hansong , Nam Jin , Agarwal Sudha 
Published: August 2008

AbstractSkeletal muscle fiber construction for tissue‐engineered grafts requires assembly of unidirectionally aligned juxtaposed myotubes. To construct such a tissue, a polymer microchip with linearly aligned microgrooves was fabricated that could direct myoblast adaptation under stringent conditions. The closely spaced microgrooves fabricated by a modified replica molding process guided linear cellular alignment. Examination of the myoblasts by immunofluorescence microscopy demonstrated that the microgrooves with subcellular widths and appropriate height‐to‐width ratios were required for practically complete linear alignment of myoblasts. The topology‐dependent cell alignment encouraged differentiation of myoblasts into multinucleate, myosin heavy chain positive myotubes. The monolayer of myotubes formed on the microstructured chips allowed attachment, growth and differentiation of subsequent layers of linearly arranged myoblasts, parallel to the primary monolayer of myotubes. The consequent deposition of additional myoblasts on the previous layer of myotubes resulted in three‐dimensional multi‐layered structures of myotubes, typical of differentiated skeletal muscle tissue. The findings demonstrate that the on‐chip device holds promise for providing an efficient means for guided muscle tissue construction. Biotechnol. Bioeng. 2009;102: 624–631. © 2008 Wiley Periodicals, Inc.
Combinatorial, selective and reversible control of gene expression using oligodeoxynucleotides in a cell‐free protein synthesis system
Authors: Keum Jung‐Won , Ahn Jin‐Ho , Kang Taek Jin , Kim Dong‐Myung 
Published: August 2008

AbstractHerein we describe the methods for selective and reversible regulation of gene expression using antisense oligodeoxynucleotides (ODNs) in a cell‐free protein synthesis system programmed with multiple DNAs. Either a complete shut down or controlled level of gene expression was attained through the antisense ODN‐mediated regulation of mRNA stability in the reaction mixture. In addition to the primary control of gene expression, we also demonstrate that the inhibition of protein synthesis can be reversed by using an anti‐antisense ODN sequence that strips the antisense ODN off the target sequence of mRNA. As a result, sequential additions of the antisense and anti‐antisense ODNs enabled the stop‐and‐go expression of protein molecules. Through the on‐demand regulation of gene expression, presented results will provide a versatile platform for the analysis and understanding of the complicated networks of biological components. Biotechnol. Bioeng. 2009;102: 577–582. © 2008 Wiley Periodicals, Inc.
Peritoneal pseudomyxoma: results of a systematic policy of complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy
Authors: Elias D , Honoré C , Ciuchendéa R , Billard V , Raynard B , Lo Dico R , Dromain C , Duvillard P , Goéré D 
Published: August 2008

Abstract

Background
Pseudomyxoma peritonei (PMP) is characterized by progressive intraperitoneal accumulation of mucous and mucinous implants, usually derived from a ruptured, possibly malignant mucinous neoplasm of the appendix. Treatment based on complete cytoreductive surgery (CCRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is gaining support. The aim of this study was to identify pre- and perioperative factors of prognostic value.

Methods
A total of 105 patients (with no residual tumours exceeding 2 mm) were treated with CCRS plus HIPEC based on oxaliplatin. Clinical, radiological, pathological factors and blood markers were analysed to determine their prognostic value for survival.

Results
Mortality (7·6 per cent) and morbidity (67·6 per cent) were significantly correlated with peritoneal index, pathological grade and blood CA19·9 level. The median follow-up was 48 months. Seven patients died after hospital discharge. Overall and disease-free 5-year survival rates were 80·0 and 68·5 per cent respectively. The Cox model identified only two significant factors impacting on disease-free survival: CA19·9 level and pathological grade.

Conclusion
CCRS is the most effective treatment for PMP, and adding HIPEC prolongs long-term survival. Further strategies should focus on improving postoperative outcome in extended PMP.
Adipose-derived mesenchymal stem cells in biosutures do not improve healing of experimental colonic anastomoses
Authors: Pascual I , de Miguel G Fernández , Gómez-Pinedo U A , de Miguel F , Arranz M García , García-Olmo D 
Published: August 2008

Abstract

Background
The feasibility of producing ‘biosutures’ coated with adipose-derived mesenchymal stem cells (ASCs) was assessed and their effect on colonic anastomoses evaluated.

Methods
Sutures were cultured with ASCs isolated from BDIX rats before analysis by light and scanning electron microscopy. Anastomoses were performed in 40 BDIX rats using either biosutures or conventional sutures. Histopathological features, adhesion formation and anastomotic strength were evaluated.

Results
Sutures were coated with ASCs within 24 h. Anastomoses made with biosutures had a lower adhesion index only during the first week (P = 0·006 at 7 days), but not subsequently. There were no significant differences in anastomotic healing with the two types of suture.

Conclusion
ASC biosutures have no effect on anastomotic healing in rats.
Outcome of pylorus-preserving gastrectomy for early gastric cancer
Authors: Morita S , Katai H , Saka M , Fukagawa T , Sano T , Sasako M 
Published: August 2008

Abstract

Background
Pylorus-preserving gastrectomy has been introduced as a function-preserving operation for early gastric cancer in Japan. The aim of this study was to investigate the safety and radicality of the procedure.

Methods
Between 1995 and 2004, 611 patients with apparent early gastric cancer in the middle third of the stomach had pylorus-preserving gastrectomy. The short-term surgical and long-term oncological outcomes of these operations were assessed.

Results
The accuracy of preoperative diagnosis of early gastric cancer was 94·3 per cent. Nodal involvement was seen in 62 patients (10·1 per cent). There were no postoperative deaths. Complications developed in 102 patients (16·7 per cent). Major complications, such as leakage and abscess, were observed in 19 (3·1 per cent). The most common complication was gastric stasis, occurring in 49 (8·0 per cent). The overall 5-year survival rate in patients with early gastric cancer was 96·3 per cent.

Conclusion
Pylorus-preserving gastrectomy is a safe operation with an excellent prognosis in patients with early gastric cancer. It is recommended as the standard procedure for early gastric cancer in the middle third of the stomach.
Systematic review of randomized controlled trials on the effectiveness of virtual reality training for laparoscopic surgery
Authors: Gurusamy K , Aggarwal R , Palanivelu L , Davidson B R 
Published: August 2008

Abstract

Background
Surgical training has traditionally been one of apprenticeship. The aim of this review was to determine whether virtual reality (VR) training can supplement and/or replace conventional laparoscopic training in surgical trainees with limited or no laparoscopic experience.

Methods
Randomized clinical trials addressing this issue were identified from The Cochrane Library trials register, Medline, Embase, Science Citation Index Expanded, grey literature and reference lists. Standardized mean difference was calculated with 95 per cent confidence intervals based on available case analysis.

Results
Twenty-three trials (mostly with a high risk of bias) involving 622 participants were included in this review. In trainees without surgical experience, VR training decreased the time taken to complete a task, increased accuracy and decreased errors compared with no training. In the same participants, VR training was more accurate than video trainer (VT) training. In participants with limited laparoscopic experience, VR training resulted in a greater reduction in operating time, error and unnecessary movements than standard laparoscopic training. In these participants, the composite performance score was better in the VR group than the VT group.

Conclusion
VR training can supplement standard laparoscopic surgical training. It is at least as effective as video training in supplementing standard laparoscopic training.
The frequency of metopism in Anatolian populations dated from the Neolithic to the first quarter of the 20th century
Authors: Eroğlu S. 
Published: August 2008

AbstractMetopism, which is defined as a condition in which the two pieces of the frontal bone fail to merge in early childhood, displays varying degrees of incidence. In this study, the variation of the frequency of metopism across historical periods is investigated on the skulls of 487 adults from 12 different Ancient Anatolian populations dated to various periods of history ranging from the Neolithic to the first quarter of the 20th century. In addition, the study also examines the relationship of metopism to sex and cranial form. It is revealed that the frequency of metopism showed a relative increase across time periods in Anatolia after the Neolithic Period, with the exception of the Cevizcioğlu Çiftliği population. However, no significant relationship was found between metopism and cranial form or sex. It is found that the frequency of metopism in Ancient Anatolia had a distribution range of 3.3–14.9%. This distribution shows that the inhabitants of Anatolia have a heterogeneous genetic make‐up due to the geographical situation of Anatolia, which has been open to gene flow both in the past and at present. Clin. Anat. 21:471–478, 2008. © 2008 Wiley‐Liss, Inc.
Solution Structure of a Functional Biomimetic and Mechanistic Implications for Nickel Superoxide Dismutases
Authors: Schmidt Matthias , Zahn Stefan , Carella Michela , Ohlenschläger Oliver , Görlach Matthias , Kothe Erika , Weston James 
Published: August 2008

AbstractThe nickel complex of a synthetic nonapeptide (HCDLPCFVY‐NH2) is capable of catalytically disproportionating O2.− and is thus a functional biomimetic for nickel superoxide dismutases. This represents a simplification as compared to a NiSOD “maquette” that is based on a dodecapeptide that was recently reported [Inorg. Chem. 2006, 45, 2358]. The 3D solution structure reveals that the first six residues form a stable macrocyclic structure with a preformed binding site for NiII. Proline 5 exhibits a trans peptide linkage in the biomimetic and a cis conformation in NiSOD enzymes. DFT calculations reveal the source of this preference. Mechanistic consequences for the mode of action (identity of the fifth ligand) are discussed. The SOD activity is compared to enzymatic systems, and selected modifications allowed the biomimetic to be reduced to a functional minimal motif of only six amino acids (ACAAPC‐NH2).
Equilibrium and Kinetics of the Extraction of Propionic Acid Using Tri‐n‐Octylphosphineoxide
Authors: Keshav A. , Wasewar K. L. , Chand S. 
Published: August 2008

AbstractOrganophosphorous compounds have been widely used in inorganic analysis for the extraction and separation of inorganic acids or metal species. Since these compounds can form hydrogen bonds to proton donors, they can also be used for the extraction of acidic organic compounds. Therefore, the reactive extraction of propionic acid using tri‐n‐octylphosphine oxide (TOPO) in hexane was studied. Equilibrium and kinetics experiments were performed. The extraction of propionic acid using n‐heptane, light liquid paraffin, heavy liquid paraffin and hexane was studied and hexane was found to be most suitable diluent. The equilibrium complexation constant for the propionic acid‐TOPO complex was determined to be 0.702 m3/kmol. The extraction was found to be first order in propionic acid and first order in TOPO with the overall rate constant as 46.91 (m3/kmol)2/s.