bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strategies toward well‐defined polymer nanoparticles inspired by nature: Chemistry versus versatility
Authors: Elsabahy Mahmoud , Wooley Karen L. 
Published: February 2012

AbstractPolymeric nanoparticles are promising delivery platforms for various biomedical applications. One of the main challenges toward the development of therapeutic nanoparticles is the premature disassembly and release of the encapsulated drug. Among the different strategies to enhance the kinetic stability of polymeric nanoparticles, shell‐ and core‐crosslinking have been shown to provide robust character, while creating a suitable environment for encapsulation of a wide range of therapeutics, including hydrophilic, hydrophobic, metallic, and small and large biomolecules, with gating of their release as well. The versatility of shell‐ and core‐crosslinked nanoparticles is driven from the ease by which the structures of the shell‐ and core‐forming polymers and crosslinkers can be modified. In addition, postmodification with cell‐recognition moieties, grafting of antibiofouling polymers, or chemical degradation of the core to yield nanocages allow the use of these robust nanostructures as “smart” nanocarriers. The building principles of these multifunctional nanoparticles borrow analogy from the synthesis, supramolecular assembly, stabilization, and dynamic activity of the naturally driven biological nanoparticles such as proteins, lipoproteins, and viruses. In this review, the chemistry involved during the buildup from small molecules to polymers to covalently stabilized nanoscopic objects is detailed, with contrast of the strategies of the supramolecular assembly of polymer building blocks followed by intramicellar stabilization into shell‐, core‐, or core–shell‐crosslinked knedel‐like nanoparticles versus polymerization of polymers into nanoscopic molecular brushes followed by further intramolecular covalent stabilization events. The rational design of shell‐crosslinked knedel‐like nanoparticles is then elaborated for therapeutic packaging and delivery, with emphasis on the polymer chemistry aspects to accomplish the synthesis of such nanoparticulate systems. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Synthesis of tadpole polymers via triple click reactions: Copper‐catalyzed azide–alkyne cycloaddition, diels–alder, and nitroxide radical coupling reactions
Authors: Dedeoglu Tuba , Durmaz Hakan , Hizal Gurkan , Tunca Umit 
Published: February 2012

AbstractWe designed a trifunctional initiator (3) containing anthracene, bromide, and OH functionalities and subsequently used as an initiator in atom transfer radical Polymerization (ATRP) of styrene to yield linear polystyrene (PS) with α‐anthracene, OH, and ω‐bromide terminal groups, of which bromide is later transformed into azide to result in the linear anthracene‐, OH‐, and azide‐terminated PS (l‐α‐anthracene‐OH‐ω‐azide‐PS). The copper‐catalyzed azide–alkyne cycloaddition reaction between l‐α‐anthracene‐OH‐ω‐azide‐PS and α‐furan‐protected‐maleimide‐ω‐alkyne linkage, 4 afforded the linear anthracene‐, OH‐, and maleimide‐terminated PS. The cyclization via intramolecular Diels–Alder click reaction of this linear PS and the subsequent conversion of the hydroxyl into bromide resulted in the cyclic PS with one bromide located on the ring, (c‐PS)‐Br. Finally, the c‐PS‐Br was clicked with either well‐defined tetramethylpiperidine‐1‐oxyl‐terminated poly(ethylene glycol) (PEG) or poly(ε‐caprolactone) (PCL) yielding the tadpole polymer, (c‐PS)‐b‐PEG or (c‐PS)‐b‐PCL. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Predicting parenting stress in caregivers of children with brain tumours
Authors: Bennett Emily , English Martin William , Rennoldson Michael , Starza‐Smith Arleta 
Published: February 2012

AbstractObjectiveThe purpose of the study was to identify factors that contribute to parenting stress in caregivers of children diagnosed with brain tumours.MethodsThe study was cross‐sectional and recruited 37 participants from a clinical database at a specialist children's hospital. Parents were sent questionnaires, which were used to measure factors related to stress in caregivers of children diagnosed with a brain tumour. Stress levels were measured using the Parenting Stress Index—Short Form (PSI/SF). Correlation analysis and multiple linear regression were used to examine the associations between parenting stress and coping styles, locus of control, parent‐perceived child disability and time since diagnosis.ResultsResults revealed that 51% of parents were experiencing clinically significant levels of stress. The mean stress level of parents in the study was significantly higher than the PSI/SF norms (t = 4.7, p < .001). Regression analysis revealed that external locus of control and coping by accepting responsibility accounted for 67% of the variance in parenting stress. Other styles of coping, child behaviour problems and the amount of time since diagnosis were not found to be predictive of levels of parenting stress.ConclusionsThere was a high prevalence of parenting stress in caregivers of children with a brain tumour. An external locus of control and coping by accepting responsibility increased the likelihood of elevated levels of stress. Results emphasised the importance of ongoing support for parents of children with brain tumours. Intervention might helpfully be centred on strategies to increase parents' internal locus of control. Copyright © 2012 John Wiley & Sons, Ltd.
Beta‐blockers in patients with asthma and COPD
Authors: Spencer Rachel , Serumaga Brian 
Published: February 2012

AbstractIn this series we present a number of prescribing safety indicators developed as part of an RCGP project.1 The evidence base behind each of the indicators is given along with information to illustrate their clinical significance. We provide a ‘real‐life’ audit based on the indicator to show how practices could begin to analyse their own prescribing data. Copyright © 2012 Wiley Interface Ltd
Concise guide to diagnosis and management of conjunctivitis
Authors: Tey Adrian 
Published: February 2012

AbstractConjunctivitis is a common presentation in the primary‐care setting. Although it is usually self‐limiting, early identification with optimal treatment is important to avoid complications. Our Drug review describes the various clinical features of conjunctivitis and recommended management, followed by a review of prescription data and sources of further information. Copyright © 2012 Wiley Interface Ltd
The self assembly of thymine at Au(110)/liquid interfaces
Authors: Molina Contreras J. R. , Smith C. I. , Bowfield A. , Tillner F. , Weightman P. 
Published: February 2012

AbstractWe show that thymine self‐assembles into an ordered structure when adsorbed at a Au(110)/liquid interface. Reflection anisotropy spectroscopy (RAS) shows that as found for cytosine and adenine the adsorbed thymine molecules are oriented essentially vertically on the Au(110) surface with the molecule aligned along one of the principal axes of the Au(110) surface. Simulations of the RA spectra to an empirical model indicates that as found for adsorbed cytosine and adenine, thymine is aligned along the [$1{\bar {1}}0$] direction on the Au(110) surface.
Single molecule electrical excitation
Authors: Nothaft Maximilian , Höhla Steffen , Jelezko Fedor , Pflaum Jens , Wrachtrup Jörg 
Published: February 2012

AbstractOptical studies of individual molecules offer the unique possibility of investigating the local environment of single quantum objects on nanometre length scales and of employing molecular systems as non‐classical light sources at room temperature. Usually, single molecule excitation is based on optical stimulation by laser radiation. In this feature article, we present an alternative approach by utilizing charge injection in combination with molecular electron–hole recombination to electrically excite single fluorescent dyes. The successful implementation of this strategy promotes the realization of electrically driven single photon sources on demand operating at room temperature and being feasible on a vast number of molecules emitting at e.g. telecommunication wavelengths. Moreover, these probes render probing the charge carrier transport and recombination on molecular length scales. In this article, we will first discuss the interaction of single charge carriers with optically excited molecules characterized by a decrease of photoluminescence intensity with increasing current density. As it is demonstrated, this effect originates from strong electrical pumping of triplet state populations upon charge carrier recombination. Secondly, the prospect of using phosphorescent emitters as electrically driven single photon sources at room temperature will be discussed. Finally, we will highlight that photoluminescence quenching of single fluorescent dyes provides a sensitive tool to quantify local current densities and recombination dynamics in operational organic light emitting diode devices with molecular spatial resolution.
Ab initio density functional theory calculation of stacking fault energy and stress in 3C‐SiC
Authors: Umeno Yoshitaka , Yagi Kuniaki , Nagasawa Hiroyuki 
Published: February 2012

AbstractStacking faults (SFs) in the cubic polytype of silicon carbide (3C‐SiC) can bring about the leakage current in devices or cause warping of wafers. Along with experimental efforts with the aim to reduce SFs in 3C‐SiC, theoretical approach is needed to reveal the mechanical aspects of SFs. In this study, we employ ab initio density functional theory calculations to investigate the fundamental mechanical properties of SFs in cubic SiC, including the effect of stress and doping atoms (substitution of C by N or Si). Stress and strain induced by SF formation is quantitatively evaluated. Calculation of SF energies indicates that extrinsic SFs are stable. The extrinsic SFs containing double and triple SiC layers are found to be slightly more stable than the single‐layer extrinsic SF, which supports experimental observations. Neglecting the effect of local strain induced by doping, nitrogen doping around an SF obviously increase the SF formation energy, while SFs seem to be easily formed in Si‐rich models. Effect of tensile or compressive stress on SF energies is found to be very small, suggesting stress condition (large compression) induced by substitution of C atoms by Si should not substantially change the formability of SFs.
Analysis of the performance of DFT functionals in the study of light emission by oxyluciferin analogs
Authors: Pinto da Silva Luís , Esteves da Silva Joaquim C. G. 
Published: February 2012

AbstractFirefly bioluminescence has attracted much attention from the research community due to its most intriguing multicolor bioluminescence. Computational studies have been fundamental to the clarification of this phenomenon. However, no clear demonstration of the accuracy of the theoretical methods used in this field of research has been provided. In this work, we have used luciferin and dehydroluciferin in water as a model for the calculation of the emission wavelength of oxyluciferin and analogs. This model was used in a density functional theory (DFT) benchmarking in which 24 functionals were tested. A non‐negligible “case to case” dependence was observed. However in general, the better classes of the DFT functionals are generalized gradient approximation (GGA) and meta GGA. The generalized gradient exchange functional TPSSVWN5, the hybrid‐meta GGA functional mPWKCIS, and the hybrid GGA functional MPWLYP1M also present good results. For the contrary, the popular hybrid GGA functionals present a worse performance. © 2012 Wiley Periodicals, Inc.
Comparison of a simulated λ Cro dimer conformational ensemble to its NMR models
Authors: Ahlstrom Logan S. , Miyashita Osamu 
Published: February 2012

AbstractSeveral solved X‐ray structures and an NMR ensemble of the dimeric λ Cro protein markedly differ from one another, leaving its dominant solution conformation in question. Recently performed replica exchange molecular dynamics simulations starting from crystal structure coordinates sample a range of conformational space that correlates well with the X‐ray structures but differs notably from the NMR models. To further investigate the latter observation, this study focuses on additional simulation beginning from an NMR model. Network analysis and a free energy surface show that the trajectory immediately converges to a region of conformational space in agreement with the previously run simulations and the crystal structures, but they suggest that the NMR models are not stable solution conformations. Insufficient intersubunit nuclear Overhauser enhancement restraints and the absence of electrostatics in the structure calculation may have compromised the global conformation of the NMR models. © 2012 Wiley Periodicals, Inc.
Utility of Drain Fluid Amylase Measurement on the First Postoperative Day after Pancreaticoduodenectomy
Authors: Sutcliffe Robert P. , Battula Narendra , Haque Ali , Ali Amir , Srinivasan Parthi , Atkinson Simon W. , Rela Mohamed , Heaton Nigel D. , Prachalias Andreas A. 
Published: February 2012

AbstractBackgroundEarly detection of pancreatic fistula (PF) may improve the outcome after pancreaticoduodenectomy, and exclusion of PF may allow earlier drain removal and accelerate recovery. The aim of the present study was to evaluate the relationship between drain fluid amylase on the first postoperative day (DFA1) and PF.Patients and methodsThis work was designed as a prospective study and included patients undergoing pancreaticoduodenectomy in a single center. For each patient, DFA was measured on the first and fifth postoperative days, and PF was defined by drainage of amylase‐rich fluid on the fifth postoperative day (DFA5 >300 U/l). A cut‐off value of DFA1 was derived, which yielded sensitivity and negative predictive value of 100% for predicting a PF.ResultsA total of 70 patients (47% male) who underwent pancreaticoduodenectomy (Whipple procedure: 37; pylorus‐preserving procedure: 33) between April 2009 and March 2010 were included. Nine of those patients developed a PF (grade A‐2; B‐5; C‐2). There were two postoperative deaths (3%). The DFA1 value significantly correlated with DFA5 (Spearman rank coefficient 0.68; p < 0.0001). The median DFA1 of patients with a PF (6,205; range 357–23,391) was significantly higher than in patients without a PF (69; range 5–5,180; p = 0.01; unpaired t test). No patient with a PF had a DFA1 ≤350 U/l, compared to 48/61 patients (79%) without a PF. Using 350 U/l as a cut‐off, a low DFA1 excluded a PF with a sensitivity, specificity, positive and negative predictive values of 100, 79, 41, and 100%, respectively.ConclusionsDrain fluid amylase on the DFA1 after pancreaticoduodenectomy stratifies patients according to likelihood of developing a PF.
Comparison of Survival Rates for Abdominal Aortic Aneurysm Treatment Methods
Authors: Hinterseher Irene , Kuffner Herold , Koch Rainer , Gäbel Gabor , Saeger Hans D. , Smelser Diane 
Published: February 2012

AbstractBackgroundWe compared relative survival rates of patients after various operative treatments for abdominal aortic aneurysm (AAA) to those for the general population. We calculated a point of “recovery,” defined as the survival rate equal to that of the general population.MethodsSurvival data were collected from patients who underwent open repair for a ruptured AAA (rAAA), elective open repair of an AAA (OPEN), and endovascular repair (EVAR) in our hospital between 1995 and 2005. The cumulative relative survival rate and time‐specific relative survival rate were calculated for these patients compared to those for the general population. The point of “recovery” was defined as the cumulative relative survival rate equaling the survival rate for the population, and the time‐specific relative survival rate reaching 1.0.ResultsThe cumulative relative survival rate of the patients immediately after OPEN was lower than for the comparison group at the time the cumulative relative survival rate was regained. The time‐specific relative survival rate of the rAAA reached 1.0 at 16 months following emergency surgery, and for OPEN after 10 months. The cumulative relative survival rate in the EVAR group had no impairment following intervention. The relative long‐term survival rate in all three surgical groups was the same as that for the general German population.ConclusionsPatients treated successfully for AAA have the same relative long‐term survival as the general population. The time required to reach the same survival, however, differs between the treatment groups and is longest in the group with a rAAA. The variable survival rates should be taken into consideration when treating patients with an AAA.
Outcome of Operative Therapy of Hepatic Metastatic Stomach Carcinoma: A Retrospective Analysis
Authors: Schildberg Claus W. , Croner R. , Merkel S. , Schellerer V. , Müller V. , Yedibela S. , Hohenberger W. , Peros G. , Perrakis A. 
Published: February 2012

AbstractBackgroundIn general, hepatic metastasis from stomach carcinoma has an unfavorable prognosis. In addition, there are often further metastases in other organs, such as peritoneal carcinomatosis. The major aim of the present study was to investigate a potential curative surgical approach in these patients.Material and methodsThirty‐one patients with hepatic metastases from stomach cancer were treated in the University Clinic Erlangen‐Nürnberg. The data were collected retrospectively from 1972 to 1977 and prospectively since 1978 at the Erlangen Cancer Registry. The time frame of this retrospective analysis from patients who had surgical resection of hepatic metatases from gastric cancer was from 1972 to 2008. The median age of the patients was 65 years, and the ratio of men to women was 2:1.ResultsAtypical or anatomical resections of segments were possible in 21 cases. Larger operations, such as hemihepatectomy (right/left), were performed in 10 patients. The postoperative complication rate was 29%, and the hospital mortality was 6%. The five‐year survival rate was 13%; R0 resection was achieved in 23 patients. We also found a significant difference in the 5‐year survival rate between synchronous and metachronous metastases (0 vs. 29%; p < 0.001) and R0 resected patients (p = 0.002). Patients with solitary metastases had a significantly better median survival than patients with multiple metastases (21 vs. 4 months; p < 0.005.)ConclusionsThe overall survival in our study was 13%; therefore gastric cancer with liver metastases is not in every case a palliative situation. It seems that patients with liver metastases benefit from resection, especially if the metastases are metachronous (p < 0.001) and solitary, provided that a curative R0 resection has been achieved. An interdisciplinary approach with neoadjuvant chemotherapy appears useful. Additional controlled studies should be conducted.
Fast and effective: intense pulse light photodynamic inactivation of bacteria
Authors: Maisch Tim , Spannberger Franz , Regensburger Johannes , Felgenträger Ariane , Bäumler Wolfgang 
Published: February 2012

AbstractThe goal of this study was to investigate the photodynamic toxicity of TMPyP (5, 10, 15, 20-Tetrakis (1-methylpyridinium-4-yl)-porphyrin tetra p-toluenesulfonate) in combination with short pulses (ms) of an intense pulse light source within 10 s against Bacillus atrophaeus, Staphylococcus aureus, Methicillin-resistant S. aureus and Escherichia coli, major pathogens in food industry and in health care, respectively. Bacteria were incubated with a photoactive dye (TMPyP) that is subsequently irradiated with visible light flashes of 100 ms to induce oxidative damage immediately by generation of reactive oxygen species like singlet oxygen. A photodynamic killing efficacy of up to 6 log10 (&gt;99.9999%) was achieved within a total treatment time of 10 s using a concentration range of 1–100 μmol TMPyP and multiple light flashes of 100 ms (from 20 J cm−2 up to 80 J cm−2). Both incubation of bacteria with TMPyP alone or application of light flashes only did not have any negative effect on bacteria survival. Here we could demonstrate for the first time that the combination of TMPyP as the respective photosensitizer and a light flash of 100 ms of an intense pulsed light source is enough to generate sufficient amounts of reactive oxygen species to kill these pathogens within a few seconds. Increasing antibiotic resistance requires fast and efficient new approaches to kill bacteria, therefore the photodynamic process seems to be a promising tool for disinfection of horizontal surfaces in industry and clinical purposes where savings in time is a critical point to achieve efficient inactivation of microorganisms.
A multidisciplinary evidence-based guideline for minimally invasive surgery.
Authors: la Chapelle Claire F. , Bemelman Willem A. , Rademaker Bart M. P. , van Barneveld Teus A. , Jansen Frank Willem ,   on behalf of the Dutch Multidisciplinary Guideline Development Group Minimally Invasive Surgery
Published: February 2012

AbstractThe Dutch Society for Endoscopic Surgery together with the Dutch Society of Obstetrics and Gynecology initiated a multidisciplinary working group to develop a guideline on minimally invasive surgery to formulate multidisciplinary agreements for minimally invasive surgery aiming towards better patient care and safety. The guideline development group consisted of general surgeons, gynecologists, an anesthesiologist, and urologist authorized by their scientific professional association. Two advisors in evidence-based guideline development supported the group. The guideline was developed using the “Appraisal of Guidelines for Research and Evaluation” instrument. Clinically important aspects were identified and discussed. The best available evidence on these aspects was gathered by systematic review. Recommendations for clinical practice were formulated based on the evidence and a consensus of expert opinion. The guideline was externally reviewed by members of the participating scientific associations and their feedback was integrated. Identified important topics were: laparoscopic entry techniques, intra-abdominal pressure, trocar use, electrosurgical techniques, prevention of trocar site herniation, patient positioning, anesthesiology, perioperative care, patient information, multidisciplinary user consultation, and complication registration. The text of each topic contains an introduction with an explanation of the problem and a summary of the current literature. Each topic was discussed, considerations were evaluated and recommendations were formulated. The development of a guideline on a multidisciplinary level facilitated a broad and rich discussion, which resulted in a very complete and implementable guideline.