bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and Synthesis of Multifunctional Drug Carriers Based on Luminescent Rattle‐Type Mesoporous Silica Microspheres with a Thermosensitive Hydrogel as a Controlled Switch
Authors: Kang Xiaojiao , Cheng Ziyong , Yang Dongmei , Ma Ping'an , Shang Mengmeng , Peng Chong , Dai Yunlu , Lin Jun 
Published: January 2012

AbstractA novel approach for the fabrication of multifunctional microspheres integrating several advantages of mesoporous, luminescence, and temperature responses into one single entity is reported. First, the hollow mesoporous silica capsules are fabricated via a sacrificial template route. Then, Gd2O3:Eu3+ luminescent nanoparticles are incorporated into the internal cavities to form rattle‐type mesoporous silica nanocapsules by an incipient‐wetness impregnation method. Finally, the rattle‐type capsules serve as a nanoreactor for successfully filling temperature‐responsive hydrogel via photoinduced polymerization to form the multifunctional composite microspheres. The organic–inorganic hybrid microspheres show a red emission under UV irradiation due to the luminescent Gd2O3:Eu3+ core. The in vitro cytotoxicity tests show that the samples have good biocompatibility, which indicates that the nanocomposite could be a promising candidate for drug delivery. In addition, flow cytometry and confocal laser scanning microscopy (CLSM) confirm that the sample can be effectively taken up by SKOV3 cells. For in vitro magnetic resonance imaging (MRI), the sample shows the promising spin‐lattice relaxation time (T1) weighted effect and could potentially apply as a T1‐positive contrast agent. This composite drug delivery system (DDS) provides a positive temperature controlled “on‐off”drug release pattern and the drug, indomethacin (IMC), is released fast at 45 °C (on phase) and completely shut off at 20 °C (off phase). Meanwhile Gd2O3:Eu3+ plays an important role as the luminescent tag for tracking the drug loading and release process by the reversible luminescence quenching and recovery phenomenon. These results indicate that the obtained multifunctional composite has the potential to be used as a smart DDS for biomedical applications.
Shellac‐polyamidoamine: Design of a new polymeric carrier material for controlled release application
Authors: Dey R. K. , Tiwary G. S. , Patnaik Tanushree , Jha Usha 
Published: January 2012

AbstractThe development of a pH sensitive, biodegradable polymer from the combination of Shellac (a natural polymer secreted by lac insect) and polyamidoamine (PAA) (a synthetic polymer) yielded a new biocompatible polymer Shellac‐PAA in a photopolymerization process. Scanning electron micrograph of Shellac‐PAA shows an interesting heterogeneous surface morphology supported with observation of two different melting temperatures obtained from differential scanning calorimetric measurement. The equilibrium swelling properties of the polymeric material was studied as a function of pH and time in buffer solutions similar to that of gastric and intestinal fluids. The controlled release kinetics of a model colon specific drug 5‐aminosalicylic acid showed Fickian diffusion behavior. The new polymer is biocompatible, biodegradable and, hence, projected as a new kind of polymer with improved properties, which can be a potential candidate for controlled release of therapeutic agents in colon specific diseases. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Orthogonal design study on factors affecting the degradation of polylactic acid fibers of melt electrospinning
Authors: Zhao Fengwen , Liu Yong , Yuan Huilin , Yang Weimin 
Published: January 2012

AbstractMelt electrospinning is a much simpler and safer method in the production of ultra‐fine fibers compared with solution electrospinning. However, high‐spinning temperature usually leads to serious degradation of polymer materials. In determining factors that affect the relative molecular mass of polylactic acid (PLA) fibers during melt electrospinning, an orthogonal design method was used to examine the influence of melting temperature, spinning distance, and species and content of antioxidants. Results showed that antioxidant content at the present three levels (i.e., 0.1%, 0.3%, and 0.5%) has the most considerable effect on the relative molecular mass of PLA fibers. Error analysis showed that changes in temperature, distance, and antioxidant content influence the experiment's results significantly. All interaction effects were larger than those of the single factor in the experimental results. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Ameliorating effect of chromium administration on hepatic glucose metabolism in streptozotocin‐induced experimental diabetes
Authors: Sundaram Bhuvaneshwari , Singhal Kirti , Sandhir Rajat 
Published: January 2012

AbstractChromium has been recognized as an essential trace element that plays an important role in carbohydrate metabolism. However, the molecular mechanisms involved in its action are not clear. This study was undertaken to understand the mechanism of chromium action in experimental diabetes. Streptozotocin‐induced diabetic animals were administered chromium as chromium picolinate (CrP) at a daily dose of 1 mg/kg body weight for a period of 4 weeks. It was observed that chromium complexed with picolinate was effective in lowering plasma glucose levels as well as was able to alleviate polyphagia, polydipsia, and weight loss in diabetic animals. Administration of chromium was also found to normalize glycogen content in liver of diabetic animals to near control levels. The reduction in plasma glucose levels by chromium was accompanied by increase in activity of glycolytic enzymes (e.g., glucokinase, phosphofructokinase, and pyruvate kinase) and by suppression in activity of gluconeogenic enzymes (e.g., glucose‐6‐phosphatase and phosphoenolpyruvate carboxykinase) in liver. Hepatic glucose uptake was found to be increased by chromium supplementation as demonstrated by decrease in Km and increase in Vmax values in diabetic animals. Chromium levels were lower in the liver of diabetic rats when compared with that of control rats. A negative correlation was observed between plasma glucose and chromium concentration in patients with diabetes. The data suggests that chromium supplementation as CrP is beneficial in correcting hyperglycemia, implying that the modulation of the glucose metabolism by chromium may be therapeutically beneficial in the treatment of diabetes. © 2012 International Union of Biochemistry and Molecular Biology, Inc.
Randomized clinical trial of antibiotics in acute uncomplicated diverticulitis13
Authors:   for the AVOD Study Group, Chabok A , Påhlman L , Hjern F , Haapaniemi S , Smedh K 
Published: January 2012

Abstract

Background
The standard of care for acute uncomplicated diverticulitis today is antibiotic treatment, although there are no controlled studies supporting this management. The aim was to investigate the need for antibiotic treatment in acute uncomplicated diverticulitis, with the endpoint of recovery without complications after 12 months of follow-up.

Methods
This multicentre randomized trial involving ten surgical departments in Sweden and one in Iceland recruited 623 patients with computed tomography-verified acute uncomplicated left-sided diverticulitis. Patients were randomized to treatment with (314 patients) or without (309 patients) antibiotics.

Results
Age, sex, body mass index, co-morbidities, body temperature, white blood cell count and C-reactive protein level on admission were similar in the two groups. Complications such as perforation or abscess formation were found in six patients (1·9 per cent) who received no antibiotics and in three (1·0 per cent) who were treated with antibiotics (P = 0·302). The median hospital stay was 3 days in both groups. Recurrent diverticulitis necessitating readmission to hospital at the 1-year follow-up was similar in the two groups (16 per cent, P = 0·881).

Conclusion
Antibiotic treatment for acute uncomplicated diverticulitis neither accelerates recovery nor prevents complications or recurrence. It should be reserved for the treatment of complicated diverticulitis. Registration number: NCT01008488 (http://www.clinicaltrials.gov).
The Nature of Bond Critical Points in Dinuclear Copper(I) Complexes
Authors: Dinda Shrabani , Samuelson Ashoka G. 
Published: January 2012

AbstractClosed‐shell contacts between two copper(I) ions are expected to be repulsive. However, such contacts are quite frequent and are well documented. Crystallographic characterization of such contacts in unsupported and bridged multinuclear copper(I) complexes has repeatedly invited debates on the existence of cuprophilicity. Recent developments in the application of Bader’s theory of atoms‐in‐molecules (AIM) to systems in which weak hydrogen bonds are involved suggests that the copper(I)–copper(I) contacts would benefit from a similar analysis. Thus the nature of electron‐density distributions in copper(I) dimers that are unsupported, and those that are bridged, have been examined. A comparison of complexes that are dimers of symmetrical monomers and those that are dimers of two copper(I) monomers with different coordination spheres has also been made. AIM analysis shows that a bond critical point (BCP) between two Cu atoms is present in most cases. The nature of the BCP in terms of the electron density,ρ, and its Laplacian is quite similar to the nature of critical points observed in hydrogen bonds in the same systems. Theρis inversely correlated to CuCu distance. It is higher in asymmetrical systems than what is observed in corresponding symmetrical systems. By examining the ratio of the local electron potential‐energy density (Vc) to the kinetic energy density (Gc), |Vc|/Gcat the critical point suggests that these interactions are not perfectly ionic but have some shared nature. Thus an analysis of critical points by using AIM theory points to the presence of an attractive metallophilic interaction similar to other well‐documented weak interactions like hydrogen bonding.
Creation of Chiral Thixotropic Gels through a Crown–Ammonium Interaction and their Application to a Memory‐Erasing Recycle System
Authors: Sobczuk Adam A. , Tsuchiya Youichi , Shiraki Tomohiro , Tamaru Shun‐ichi , Shinkai Seiji 
Published: January 2012

AbstractA unique class of oligothiophene‐based organogelator bearing two crown ethers at both ends was synthesized. This compound could gelatinize several organic solvents, forming one‐dimensional fibrous aggregates. From the observation of circular dichroism, it was confirmed that the helical handedness of the fibrous assembly is controllable by the chirality of 1,2bisammonium guests, thus suggesting that one guest molecule bridges two gelator molecules through the crown–ammonium interaction. Interestingly, we have found that such chirality is created by thermal gelation, whereas it disappears by thixotropic gelation. The new finding implies that the present organogel system is applicable as a reversible switching memory device, featuring memory creation by a heat mode and memory erasing by a mechanical mode.
An efficient method for effective connectivity of brain regions
Authors: Ahmad Fayyaz , Maqbool M. , Kim Eunwoo , Park Hyunwook , Kim Dae‐Shik 
Published: January 2012

AbstractRecent attention has been focused on detecting interregional connectivity in a resting state of the brain, in general, described in terms of functional connectivity based on functional magnetic resonance imaging (fMRI) data. The fMRI functional data are given in the form of multivariate time‐series. The authors have proposed a model for the effective connectivity of brain regions based on multivariate autoregressive (MAR) model. MAR modeling allows for the identification of effective connectivity by combining graphical modeling methods with the concept of Granger causality. In our current model, multivariate time‐series methods of the brain regions were performed only when the length of the time‐seriesTis sufficiently large. This is opposite of the mechanism used in functional imaging that measures relatively short time‐series over thousands of voxels of the brain. As a method of coping with this situation and also in case of sufficiently largeTorT≤d(regions), the authors present a novel and highly efficient modeling approach to detect effective connectivity of the brain regions. This proceeds in two steps: (i) accurate estimation of MAR coefficients (paths) using an analytic ridge regression approach, and (ii) network model selection by testing the associated partial correlations. The usefulness of the proposed method is confirmed by the analysis result of simulated and real fMRI experiments, and performance is shown to be high. © 2012 Wiley Periodicals, Inc. Concepts Magn Reson Part A 40: 14–24, 2012.
Implementation of two‐qubit and three‐qubit quantum computers using liquid‐state nuclear magnetic resonance
Authors: Golze Dorothea , Icker Maik , Berger Stefan 
Published: January 2012

AbstractThe field of quantum computing has grown rapidly in the last years. Most realizations of quantum computers were done on liquid‐state NMR quantum computers so far. We present in a didactic approach how to build small NMR quantum computers with two and three qubits. The two‐qubit quantum computer was implemented on α‐D‐methylglucose using 13C spins, whereas the three‐qubit quantum computer was implemented on 4‐bromo‐1,1,2‐trifluoro‐1‐butene using 19F spins. We describe in detail how to initialize these systems by generating pseudo‐pure states. For initialization, we used the spatial averaging method, which has the advantage that it can be easily understood by product operators. Furthermore, the implementation of quantum logic gate operations will be presented. © 2012 Wiley Periodicals, Inc. Concepts Magn Reson Part A 40: 25–37, 2012.
Comparative evaluation of autofocus algorithms for a real‐time system for automatic detection of Mycobacterium tuberculosis
Authors: Mateos‐Pérez José María , Redondo Rafael , Nava Rodrigo , Valdiviezo Juan C. , Cristóbal Gabriel , Escalante‐Ramírez Boris , Ruiz‐Serrano María Jesús , Pascau Javier , Desco Manuel 
Published: January 2012

AbstractMicroscopy images must be acquired at the optimal focal plane for the objects of interest in a scene. Although manual focusing is a standard task for a trained observer, automatic systems often fail to properly find the focal plane under different microscope imaging modalities such as bright field microscopy or phase contrast microscopy. This article assesses several autofocus algorithms applied in the study of fluorescence‐labeled tuberculosis bacteria. The goal of this work was to find the optimal algorithm in order to build an automatic real‐time system for diagnosing sputum smear samples, where both accuracy and computational time are important. We analyzed 13 focusing methods, ranging from well‐known algorithms to the most recently proposed functions. We took into consideration criteria that are inherent to the autofocus function, such as accuracy, computational cost, and robustness to noise and to illumination changes. We also analyzed the additional benefit provided by preprocessing techniques based on morphological operators and image projection profiling. © 2012 International Society for Advancement of Cytometry
Light‐emitting diodes in modern microscopy—from David to Goliath?
Authors: Wessels Johannes T. , Pliquett Uwe , Wouters Fred S. 
Published: January 2012

AbstractProper illumination is essential for light microscopy. Whereas in early years incandescent light was the only illumination, today, more and more specialized light sources, such as lasers or arc lamps are used. Because of the high efficiency and brightness that light‐emitting diodes (LED) have reached today, they have become a serious alternative for almost all kinds of illumination in light microscopy. LED have a high durability, do not need expensive electronics, and they can be switched in nanoseconds. Besides this, they are available throughout the UV/Vis/NIR‐spectrum with a narrow bandwidth. This makes them ideal light sources for fluorescence microscopy. The white LED, with a color temperature ranging from 2,600 up to 5,000 K is an excellent choice for bright‐field illumination with the additional advantage of simple brightness adjustments without changing the spectrum. This review discusses the different LED types, their use in the fluorescence microscope, and discusses LED as specialized illumination sources for Förster resonance energy transfer and fluorescent lifetime imaging microscopy. © 2012 International Society for Advancement of Cytometry
Expected and Unconventional Ag+ Binding Modes in Heteronuclear Pt,Ag Coordination Polymers Derived from trans‐[Pt(methylamine)2(pyrazole)2]2+
Authors: Brandi‐Blanco Pilar , Sanz Miguel Pablo J. , Lippert Bernhard 
Published: January 2012

AbstractThe combination of AgNO3 and trans‐[Pt(ma)2(Hpz)2]2+ (1; ma = methylamine; Hpz = neutral pyrazole) in water yields mixed Pt,Ag coordination polymers of different stoichiometries, depending on the ratio between Ag and Pt, as well as the pH. The products that were isolated and X‐ray structurally characterized display both conventional (Ag+ coordination to pyrazole‐N) and unconventional Ag+ binding modes (η1 and η2 binding to C atoms of the pyrazole/pyrazolate ligands; Pt → Ag dative bonds). Specifically, in trans‐[Pt(ma)2(Hpz)2]Ag2(NO3)4 (2) and in trans‐[Pt(ma)2(pz)2]2Ag3(NO3)3 (4), silver ions bind to C4 positions of Hpz (2) and pz– (4) ligands in η1 fashions, with Ag–C distances of 2.574(4) and 2.643(16) Å, respectively. In 4 there is additional cross‐linking by a second Ag+ of N2 sites of adjacent pz– rings, further reinforced by weak dative bonds from Pt to Ag. Ag–N coordination to both a neutral Hpz and an anionic pz– ligand is observed in trans‐[Pt(ma)2(pz)2]Ag2(Hpz)2(NO3)2 (5), with individual trinuclear PtAg2 entities associated through weak η2 contacts that involve the C3 and C4 positions of the neutral Hpz ligands. As in 4, intramolecular Pt–Ag distances of 3.1374(6) Å suggest weak dative bond interactions between Pt and Ag. The acidities of the two Hpz ligands in 1 are distinctly different (pKa values of 7.25 and 9.08 in H2O), thereby suggesting a stabilization of the monodeprotonated species trans‐[Pt(ma)(Hpz)(pz)]+ (1c) in solution, probably through intermolecular hydrogen‐bond formation between Hpz and pz– ligands.
Effects of Silyl Substituents on the Palladium‐Catalyzed Asymmetric Synthesis of Axially Chiral (Allenylmethyl)silanes and Their SE2′ Chirality Transfer Reactions
Authors: Ogasawara Masamichi , Ge Yonghui , Okada Atsushi , Takahashi Tamotsu 
Published: January 2012

AbstractA series of axially chiral 4‐substituted‐1‐silyl‐2,3‐butadienes [(allenylmethyl)silanes] were synthesized from 3‐bromo‐5‐silylpenta‐1,3‐dienes by a Pd‐catalyzed asymmetric reaction with a soft nucleophile. The optically active (allenylmethyl)silanes react with an acetal in the presence of TiCl4 to give the enantiomerically enriched 1,3‐diene derivatives through an SE2′ pathway. Effects of the silyl groups on the enantioselectivity of the asymmetric allene synthesis and the subsequent SE2′ chirality transfer reaction were studied. It was found that as the steric bulk of the silyl groups in the 3‐bromo‐5‐silylpenta‐1,3‐dienes was increased from ‐SiMe3 to ‐SiiPr3, the enantioselectivity of the two enantioselective processes also improved.
Electricity—renewables & transmission: Hidden challenges and increasing rewards of renewable procurement
Authors: Judd Harold T. , Liakos Kathleen 
Published: January 2012

AbstractThe increasing prevalence of renewable energy development brings several issues to light within the energy procurement industry. Consumers and utility companies alike are taking advantage of the benefits of the cleaner renewable energy sources such as solar, wind, biomass, geothermal, methane capture, and low‐head hydroelectric. However, the benefits of renewable resources are at times offset by costs that are unknown to the public, and at times to developers. In particular, too often little thought is given to the cost of transmission and distribution systems needed to deliver electricity from a project to the ultimate customer. Also, the process for procuring electricity from renewable projects is often misunderstood. What follows is a brief introduction to the typical procurement process and the challenges facing developers and the utilities that buy their output.
Incidence rates of endometrial hyperplasia, endometrial cancer and hysterectomy from 1980 to 2003 within a large prepaid health plan
Authors: Lacey James V. , Chia Victoria M. , Rush Brenda B. , Carreon Danny J. , Richesson Douglas A. , Ioffe Olga B. , Ronnett Brigitte M. , Chatterjee Nilanjan , Langholz Bryan , Sherman Mark E. , Glass Andrew G. 
Published: January 2012

AbstractObesity strongly increases the risk of endometrial cancer and is projected to increase current and future endometrial cancer incidence. In order to fully understand endometrial cancer incidence, one should also examine both hysterectomy, which eliminates future risk of endometrial cancer, and endometrial hyperplasia (EH), a precursor that prompts treatment (including hysterectomy). Hysterectomy and EH are more common than endometrial cancer, but data on simultaneous temporal trends of EH, hysterectomy and endometrial cancer are lacking. We used linked pathology, tumor registry, surgery and administrative datasets at the Kaiser Permanente Northwest Health Plan to calculate age‐adjusted and age‐specific rates, 1980–2003, of EH only (N = 5,990), EH plus hysterectomy (N = 904), hysterectomy without a diagnosis of EH or cancer (N = 14,926) and endometrial cancer (N = 1,208). Joinpoint regression identified inflection points and quantified annual percentage changes (APCs). The EH APCs were −5.3% (95% confidence interval [CI] = −7.4% to −3.2%) for 1980–1990, −12.9% (95% CI = −15.6% to −10.1%) for 1990–1999 and 2.4% (95% CI = −6.6% to 12.2%) for 1999–2003. The EH‐plus‐hysterectomy APCs were −8.6% (95% CI = −10.6% to −6.5%) for 1980–2000 and 24.5% (95% CI = −16.5% to 85.7%) for 2000–2003. Hysterectomy rates did not significantly change over time. The endometrial cancer APCs were −6.5% (95% CI = −10.3% to −2.6%) for 1980–1988 and 1.4% (95% CI = −0.2% to 3.0%) for 1988–2003. Hysterectomy rates were unchanged, but increased endometrial cancer incidence after 1988 and the reversal, in 1999, of the longstanding decline in EH incidence could reflect the influence of obesity on endometrial neoplasia.
Loops, Lyrics, and Literacy: Songwriting as a Site of Resilience for an Urban Adolescent
Authors: Kinney Angela 
Published: January 2012

AbstractThis case study explores Christopher's (pseudonym) sustained participation in a nonprofit, afterschool community center, as he wrote and recorded music and lyrics in a digital recording studio. It examines the ways in which Christopher, in contrast to his performance in school, was highly participatory and engaged with textual production at the center. In particular, the author explores the purposes and functions that songwriting served for Christopher, and considers the ways in which songwriting functioned for Christopher as a “site for resilience,” or as a space in which he could navigate aspects of his lived experience. Analysis of Christopher's lyrics suggested three major areas of lived experience on which his songs centered: family experiences, peer relations, and issues in his community.