bluuebunny/crossref_metadata_2025 huggingface dataset:
Palliative surgery for head and neck cancer with extensive skin involvement
Authors: Jang David W. , Teng Marita S. , Ojo Bukola , Genden Eric M.
Published: April 2013

Objectives/Hypothesis

To evaluate the role of regional and free tissue transfer for the palliative management of head and neck cancer with extensive skin involvement.

Study Design

Case Series.

Methods

A retrospective review was performed of patients treated for head and neck cancer with involvement of the skin at the Mount Sinai Medical Center over a 5‐year period (2006–2010). Only patients with extensive skin involvement and unresectable tumors who underwent palliative resection and reconstruction were included in the review. Subjects were analyzed for age, gender, performance status, primary site, tumor histology, extent of invasion, type of reconstruction, hospital course, wound complications, adjuvant therapy, survival, and cause of death.

Results

Twenty‐five patients met the inclusion criteria for the review. Fourteen patients (56%) underwent regional flap reconstruction, and 11 patients (44%) underwent free flap reconstruction. The average length of stay was 7 days. Twenty‐four patients (96%) had a medically uncomplicated postoperative hospital course. Nineteen patients (76%) were treated with adjuvant palliative radiotherapy and/or chemotherapy. Long‐term follow‐up was achieved for 19 patients. The median follow up in this group was 9.5 months. Eleven of the 21 patients (52%) developed wound complications postoperatively. Eight of these were minor wound dehiscences, while three developed major wound complications. Four patients (16%) had distant metastasis at the time of surgery, and the median time to develop distant metastases after surgery was 6 months. Median survival time was 9.5 months. Twenty‐two patients (88%) were discharged in the care of their families with appropriate pain management and without the need for extensive wound care.

Conclusions

For unresectable tumors with extensive skin involvement, palliative resection and reconstruction is a reasonable treatment option. Although survival may not be affected, addressing the odor, bleeding, pain, and infection associated with skin involvement has the potential to improve a patient's quality of life.

Level of Evidence

4.
Ex Vivo Electromechanical Reshaping of Costal Cartilage in the New Zealand White Rabbit Model
Authors: Badran Karam , Manuel Cyrus , Waki Curtis , Protsenko Dmitry , Wong Brian J. F.
Published: April 2013

Objectives/Hypothesis

Determine the effective electromechanical reshaping (EMR) parameters for shape change and cell viability in the ex vivo rabbit costal cartilage model.

Study Design

Ex vivo animal study combined with computer modeling to guide electrode placement and polarity selection.

Methods

Rabbit costal cartilages were secured in a jig that approximated the shape of the rabbit auricle framework. Finite element modeling was used to select the initial electrode geometry, polarity, spacing, and estimate dosimetry parameters. Porcine costal cartilage was utilized to refine the selection of dosing parameters. Parametric analysis was performed to determine the effect of voltage and application time on tissue shape change. Next, rabbit rib cartilage was reshaped, varying voltage and application time to identify the lowest parameters to produce acceptable shape change mimicking native auricular cartilage. Acceptable qualitative shape change was determined on a five‐point Likert scale analyzed using one‐way general linear analysis of variance. Confocal microscopy with live/dead cell viability analysis determined the degree of injury and the distribution of live and dead cells.

Results

The minimum acceptable deformation of rabbit costal cartilage was found at 4 V–3 minutes. Viability analysis of cartilage reshaped at 4 V–3 minutes demonstrates cell injury extending 2 mm away from each electrode with viable cells found between the electrodes.

Conclusions

The EMR parameters of 4 V–3 minutes demonstrates appropriate shape change producing grafts that resemble the native auricle and contains the viable cells adequate for clinical evaluation. The rabbit auricular reconstruction model using EMR is a feasible one.
The effect of steroids in combination With optic nerve decompression surgery in traumatic optic neuropathy
Authors: Ropposch Thorsten , Steger Bernhard , Meço Cem , Emesz Martin , Reitsamer Herbert , Rasp Gerd , Moser Gerhard
Published: April 2013

Objectives/Hypothesis

Traumatic optic neuropathy (TON) is an important cause of severe visual impairment following blunt or penetrating head trauma. Treatment options include steroids, decompression, or both. Studies have failed to show a clear benefit for either steroids or surgery or a combined therapy. This study describes the visual outcome in surgically managed patients with or without steroid treatment.

Study Design

Retrospective analysis.

Methods

In a retrospective chart review we included patients (n = 42) with TON who were managed with optic nerve decompression surgery with or without steroids. Comparison of initial and final visual acuity was the primary outcome parameter.

Results

In 42 consecutive patients, steroids were used in 21 cases (50%). Ten patients received a high‐dose systemic regimen of more than 500 mg methylprednisolone initial dose, and 11 patients were treated with a lower dose. The overall visual improvement rate was 33%, no change was noted in 50%, and no outcome data were available in 17%. The visual improvement rate of patients treated with decompression surgery and steroids was lower (29%, 6 of 21) than those treated with surgery alone (53%, 8 of 15). Comparing both groups, additional steroids had no beneficial effect on the visual outcome (P = .97). There was no case with a deterioration of visual function due to therapy.

Conclusions

In patients with traumatic optic neuropathy who were treated with optic nerve decompression surgery, steroids had no beneficial effect on the visual outcome.

Level of Evidence

2c.
The effect of continuous positive airway pressure on middle ear pressure
Authors: Sivri Bekir , Sezen Ozan Seymen , Akbulut Sevtap , Coskuner Temel
Published: April 2013

Objectives/Hypothesis

To investigate the effect of continuous positive airway pressure (CPAP) on middle ear pressure in patients with obstructive sleep apnea syndrome (OSAS).

Study Design

Prospective clinical case‐control study.

Methods

Seventy‐eight patients with moderate and severe OSAS (the mean apnea‐hypopnea indexes were 22.70 ± 3.59 and 48.59 ± 12.50, respectively) using CPAP (study group) and 60 patients with no sleep apnea syndrome (control group) were included in the study. Forty‐two of the patients were female and 96 were male. The mean age in the study group was 47.38 ± 6.23, whereas it was 46.10 ± 11.96 in the control group (P > .05). The middle ear pressure of all study subjects was evaluated with tympanometry at the beginning of the study and 6 months later. Tympanometric measurements of both groups were compared. Furthermore, the same data for the study group were also evaluated according to CPAP pressure levels.

Results

The middle ear peak pressure values of the patients in the study group were significantly increased from −63.04 ± 55.82 daPa to −39.6 ± 27.72 daPa after 6 months (P < .01). The middle ear pressure in the control group was found to be −13.26 ± 22.60 daPa at the beginning of the study and −13.60 ± 38.82 daPa after 6 months (P > .05). The mean middle ear pressure level was significantly higher in patients using CPAP at 12 to 14 cm H2O pressure than in those using CPAP at 8 to 10 cm H2O pressure (P < .05).

Conclusions

There was a significant increase in the middle ear pressure of patients using CPAP regularly for 6 months. This increase was proportional to the pressure level of the CPAP device.

Level of Evidence

3b.
Transoral robotic surgery for treatment of obstructive sleep apnea‐hypopnea syndrome
Authors: Lin Ho‐Sheng , Rowley James A. , Badr M. Safwan , Folbe Adam J. , Yoo George H. , Victor Lyle , Mathog Robert H. , Chen Wei
Published: April 2013

Objectives/Hypothesis

To evaluate the efficacy of base of tongue (BOT) resection via transoral robotic surgery (TORS) in the treatment of obstructive sleep apnea/hypopnea syndrome (OSAHS).

Study Design

Case series

Methods

Between June 2010 and May 2012, BOT resection via TORS was performed on 27 patients with OSAHS. Patients were excluded from this analysis if other concomitant upper airway procedures such as uvulopalatopharyngoplasty were performed, or if postoperative polysomnograms were not available.

Results

Twelve patients who underwent BOT resection alone were included in this study. The median age for these 12 patients was 48.5 (range, 19–64) and included nine females and three males. The mean apnea‐hypopnea index (AHI) was 43.9 ± 41.1 preoperatively and 17.6 ± 16.2 postoperatively. This difference in AHI was statistically significant (P = 0.007) and reflected an average AHI reduction of 56.2 ± 28.3%. Statistical significant reductions in daytime somnolence level, as measured by Epworth Sleepiness Scale (13.7 ± 5.2 preoperatively vs. 6.4 ± 4.5 postoperatively, P <0.001), and snoring intensity, as reported by a bed partner using a Visual Analogue Scale (8.6 ± 1.2 preoperatively vs. 4.2 ± 1.9 postoperatively, P <0.001), were achieved. There was no statistical significant difference between the preoperative and postoperative body mass index (34.5 ± 7.3 vs. 33.5 ± 6.7, P = 0.296) or minimum oxygen saturation (83.3 ± 5.5% vs. 84.0 ± 6.4%, P = 0.680).

Conclusions

This is the first study looking at the use of TORS to address obstruction at the level of BOT only, not confounded by surgical alterations at other levels of upper airway. This preliminary result on the use of BOT resection via TORS for the treatment of patients with OSAHS is encouraging and warrants further investigations.

Level of Evidence

4. Laryngoscope, 2012
Role of Toll-Like Receptor 4 in Mediating Multiorgan Dysfunction in Mice With Acetaminophen Induced Acute Liver Failure
Authors: Shah Naina , Montes de Oca Montserrat , Jover-Cobos Maria , Tanamoto Ken-ichi , Muroi Masashi , Sugiyama Kei-ichi , Davies Nathan A. , Mookerjee Rajeshwar P. , Dhar Dipok Kumar , Jalan Rajiv
Published: April 2013

Strategies for the prevention of multiorgan dysfunction (MOD) in acetaminophen (APAP)-induced acute liver failure (ALF) are an unmet need. Our study tested the hypothesis that sterile inflammation induced by APAP in a mouse model would activate toll-like receptor 4 (TLR4) in the liver and extrahepatic organs and lead to the progression of ALF and MOD and that the administration of the novel TLR4 antagonist STM28 (a peptide formed of 17 amino-acids) would prevent liver injury and associated MOD. ALF and, subsequently, MOD were induced in TLR4-knockout (KO) mice (B6.B10ScN-Tlr4

lpsdel
/JthJ) and wild-type (WT) mice (C57BL/6) with APAP (500 mg/kg). A second set of experiments was conducted to evaluate the effects of a pretreatment with a novel TLR4 antagonist, STM28, on APAP-induced MOD in CD1 mice. Animals were sacrificed at the coma stage, and plasma, peripheral blood cells, liver, kidneys, and brain were collected. Biochemistry values and cytokines were measured. Liver and kidneys were studied histologically and were stained for TLR4 and activated Kupffer cells, and the expression of nuclear factor kappa B–p65 was quantified with western blotting. Brain water was measured in the frontal cortex. After APAP administration, TLR4-KO (NFkBp65) mice were relatively protected from liver necrosis and end-organ dysfunction and had significantly better survival than WT controls (P < 0.01). STM28 attenuated liver injury and necrosis, reduced creatinine levels, and delayed the time to a coma significantly. The increases in cytokines in the plasma and liver, including TLR4 expression and the activation of Kupffer cells, after APAP administration were reduced significantly in the STM28-treated animals. The increased number of circulating myeloid cells was reduced significantly after STM28 treatment. In conclusion, these data provide evidence for an important role of the TLR4 antagonist in the prevention of the progression of APAP-induced ALF and MOD. Liver Transpl 19:751–761, 2013.. © 2013 AASLD.
A New Approach to Morphology Studies on Diacrylate Polymer Networks Using X‐Ray Powder Diffraction
Authors: Barszczewska‐Rybarek Izabela M.
Published: April 2013

X‐ray powder diffraction (XRPD) and Fourier transform infrared (FTIR) spectroscopy are used to characterize the morphology of diacrylate polymer networks, obtained by photoinduced homo‐ and copolymerizations. XRPD reveals the presence of three sized groups of microgel agglomerates. The dimensions of the microgel agglomerates (D) and the degree of conversion (DC) are explained by the monomer chemical structure, the strength of hydrogen bonds, and relate to selected polymer mechanical properties. The D value increases and the DC decreases as the strength of the hydrogen bonds increases. Copolymerization with monomers lacking groups forming strong hydrogen bonds results in more homogeneous networks with improved mechanical properties.

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Analytic imperfect bifurcation theorem and the Liouville‐Gel’fand equation on a perturbed annular domain
Authors: Kan Toru , Miyamoto Yasuhito
Published: April 2013

An imperfect bifurcation is studied in a framework of functional analysis. We obtain a sufficient condition for an imperfect bifurcation and classify the types of imperfect bifurcations when an analyticity condition is imposed. It is almost impossible to ascertain the assumptions of existing imperfect bifurcation theorems when the degenerate solution is not constant. Our sufficient condition does not require the inverse of the linearized operator. As a nontrivial application of our imperfect bifurcation theorem, we are concerned with the Liouville‐Gel’fand equation on a two‐dimensional perturbed annular domain.
Global Lp estimates for degenerate Ornstein‐Uhlenbeck operators with variable coefficients
Authors: Bramanti M. , Cupini G. , Lanconelli E. , Priola E.
Published: April 2013

We consider a class of degenerate Ornstein‐Uhlenbeck operators in \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\mathbb {R}^{N}\!$\end{document}, of the kind

where (aij) is symmetric uniformly positive definite on \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\mathbb {R}^{p_{0}}$\end{document} (p0 ≤ N), with uniformly continuous and bounded entries, and (bij) is a constant matrix such that the frozen operator \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\mathcal {A}_{x_{0}}$\end{document} corresponding to aij(x0) is hypoelliptic. For this class of operators we prove global Lp estimates (1 < p < ∞) of the kind:

We obtain the previous estimates as a byproduct of the following one, which is of interest in its own:

for any \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$u\in C_{0}^{\infty }\!\left( S_{T}\right) ,$\end{document} where ST is the strip \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\mathbb {R}^{N}\times \left[-T,T\right]$\end{document}, T small, and L is the Kolmogorov‐Fokker‐Planck operator

with uniformly continuous and bounded aij's.
Near‐Infrared Polymer Light‐Emitting Diodes Based on Low‐Energy Gap Oligomers Copolymerized into a High‐Gap Polymer Host
Authors: Steckler Timothy T. , Fenwick Oliver , Lockwood Toby , Andersson Mats R. , Cacialli Franco
Published: April 2013

Near‐infrared (NIR) polymer light‐emitting diodes (PLEDs) based on a fluorene–dioctyloxyphenylene wide‐gap host material copolymerized with a low‐gap emitter are presented. Various loadings (1, 2.5, 10, 20 mol%) of the low‐gap emitter are studied, with higher loadings leading to decreased efficiencies likely due to aggregation effects. While the 10 mol% loading resulted in almost pure NIR emission (>99.6%), the 1 mol% loading yielded optimum device performance, which is among the best reported to date for a unblended single‐layer pure polymer emitter, with an external quantum efficiencies of 0.04% emitting at 909 nm. The high spectral purity of the PLEDs combined with their performance support the methodology of copolymerization as an effective strategy for developing NIR PLEDs.

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The relationship between balance control and vitamin D in Parkinson's disease—a pilot study
Authors: Peterson Amie L. , Mancini Martina , Horak Fay B.
Published: April 2013

Background

Balance problems and falls are a major source of morbidity and mortality in patients with Parkinson's disease. Vitamin D supplementation reduces falls and sway in neurologically intact elderly fallers, but effects in Parkinson's disease are not established.

Methods

To study this relationship and select outcome measures for a vitamin D intervention study, balance function and vitamin D concentration were quantified in a series of Parkinson's patients in a cross‐sectional, observational study. Participants underwent a battery of 5 balance tests.

Results

Serum vitamin D concentrations were correlated inversely with Parkinson's severity, as measured by the motor Unified Parkinson's Disease Rating Scale. Among the balance measures, vitamin D concentrations were correlated with automatic posture responses to backwards translation, specifically with response strength and stance weight asymmetry.

Conclusions

These findings support the hypothesis that vitamin D plays a role in balance among patients with Parkinson's disease and identify specific outcome measures for detecting effects of vitamin D upon balance. © 2013 Movement Disorder Society
Response inhibition in motor conversion disorder
Authors: Voon Valerie , Ekanayake Vindhya , Wiggs Edythe , Kranick Sarah , Ameli Rezvan , Harrison Neil A. , Hallett Mark
Published: April 2013

Conversion disorders (CDs) are unexplained neurological symptoms presumed to be related to a psychological issue. Studies focusing on conversion paralysis have suggested potential impairments in motor initiation or execution. Here we studied CD patients with aberrant or excessive motor movements and focused on motor response inhibition. We also assessed cognitive measures in multiple domains. We compared 30 CD patients and 30 age‐, sex‐, and education‐matched healthy volunteers on a motor response inhibition task (go/no go), along with verbal motor response inhibition (color‐word interference) and measures of attention, sustained attention, processing speed, language, memory, visuospatial processing, and executive function including planning and verbal fluency. CD patients had greater impairments in commission errors on the go/no go task (P < .001) compared with healthy volunteers, which remained significant after Bonferroni correction for multiple comparisons and after controlling for attention, sustained attention, depression, and anxiety. There were no significant differences in other cognitive measures. We highlight a specific deficit in motor response inhibition that may play a role in impaired inhibition of unwanted movement such as the excessive and aberrant movements seen in motor conversion. Patients with nonepileptic seizures, a different form of conversion disorder, are commonly reported to have lower IQ and multiple cognitive deficits. Our results point toward potential differences between conversion disorder subgroups. © 2013 Movement Disorder Society
The management of heat flow in deep mines
Authors: Wagner Horst
Published: April 2013

With the ever‐increasing depth of mines, the management of heat has become a key issue for their design and operation. There are two main sources of heat: heat transfer from the rock mass into the mine workings and heat associated with mining operations. The principles of heat transfer from the rock mass are discussed and basic relationships presented. Sources of heat linked to mining operations are discussed. It is shown that in deep‐level mines, heat transfer from the rock mass accounts more than 75 % of total mine heat load. In highly mechanized coal mines, heat from the use of mining machinery is also significant. Some models of heat flow prediction for deep gold mines are presented. It is shown that in the case of deep mines, control of heat flow is more important than increasing refrigeration capacity. Examples of heat flow management methods are given.

Furthermore, the paper deals with the effects of heat on the human body and mine cooling strategies for deep mines. In detail the effects of heat on a worker are examined, heat stress and heat tolerance discussed and methods of assessing heat stress in different mining situations presented. Experiences from deep South African gold mines highlight the adverse effects of heat stress environment on safety and labour productivity. The principal methods of cooling of deep and ultra deep mines are discussed. It is shown that auto‐compression of ventilation air is a deciding factor governing the choice of surface or underground cooling of ventilation air. In the case of deep and ultra deep mines, the use of chilled service water and ice slurry has shown to be the most cost effective means of mine cooling. In the case of ice slurry as cooling medium advantage is taken of the latent heat of ice which significantly reduces the amount of water required for mine cooling and hence the cost of pumping the water to surface. Cooling strategies for moderately deep, deep and ultra deep mines are discussed. Examples of cooling of deep long mine tunnels are given.
Auto‐calibration approach for k–t SENSE
Authors: Ponce Irene P. , Blaimer Martin , Breuer Felix A. , Griswold Mark A. , Jakob Peter M. , Kellman Peter
Published: April 2013

Purpose

The goal of this work is to increase the spatial resolution of training data, used by reconstruction methods such as k–t SENSE in order to calculate the missing data in a series of dynamic images, without compromising their temporal resolution or acquisition time.

Theory

The k‐t SENSE method allows dynamic imaging at high acceleration factors with high reconstruction quality. However, the low resolution training data required by k‐t SENSE may cause undesired temporal filtering effects in the reconstructed images.

Methods

In this work, a feedback regularization approach is applied to realize auto‐calibration of the k‐t SENSE algorithm. To that end, a full resolution training data set is calculated from the accelerated data itself using a TSENSE reconstruction. The reconstructed training data are then fed back for the actual k‐t SENSE reconstruction. For evaluation of our approach, temporal filtering effects are quantified by calculating the modulation transfer function and noise measurements are done by Monte‐Carlo simulations.

Results

Computer simulations and cardiac imaging experiments demonstrate an improved temporal fidelity of auto‐calibrated k‐t SENSE compared to standard k‐t SENSE.

Conclusion

Auto‐calibrated k‐t SENSE provides high quality reconstructions for dynamic imaging applications. Magn Reson Med 71:1123–1129, 2014. © 2013 Wiley Periodicals, Inc.
Cost‐efficient vertical handover between cellular networks and WLAN based on HMIPv6 and IEEE 802.21 MIH
Authors: Park Jongdae , Ryu Hoyoung , Lee Soon Seok , Bae Sueng Jae , Lee Ju Yong , Kim Mihui , Chung Min Young
Published: April 2013

In order to increase the capacity of wireless communication networks with minor changes and low cost, internetworking between cellular networks and wireless local area networks (WLANs) is considered as an attractive solution. In the internetworking of cellular networks and WLANs, a cost‐efficient vertical handover mechanism is required for seamless service provision. In this paper, we propose a cost‐efficient vertical handover mechanism for the packet‐based cellular networks and WLAN internetworking, where HMIPv6 and IEEE 802.21 are complementarily integrated to optimize the handover procedures. To design the mechanism, we introduce pre‐binding update and hierarchical packet forwarding concepts which can reduce handover signaling cost and delay. A mathematical model for handover rates and costs is proposed in order to analyze the proposed mechanism. In performance evaluation, we investigate how various factors affect handover rates and costs, and compare the proposed mechanism against the conventional mechanism. Copyright © 2013 John Wiley & Sons, Ltd.
Convergence of domain integrals for stress intensity factor extraction in 2‐D curved cracks problems with the extended finite element method
Authors: González‐Albuixech V.F. , Giner E. , Tarancón J.E. , Fuenmayor F.J. , Gravouil A.
Published: April 2013

The aim of this study is the analysis of the convergence rates achieved with domain energy integrals for the computation of the stress intensity factors (SIF) when solving 2‐D curved crack problems with the extended FEM (XFEM). Domain integrals, specially the J‐integral and the interaction integral, are widely used for SIF extraction and provide high accurate estimations with FEMs. The crack description in XFEM is usually realized using level sets. This allows to define a local basis associated with the crack geometry. In this work, the effect of the level set local basis definition on the domain integral has been studied. The usual definition of the interaction integral involves hypotheses that are not fulfilled in generic curved crack problems, and we introduce some modifications to improve the behavior in curved crack analyses. Despite the good accuracy of domain integrals, convergence rates are not always optimal, and convergence to the exact solution cannot be assured for curved cracks. The lack of convergence is associated with the effect of the curvature on the definition of the auxiliary extraction fields. With our modified integral proposal, the optimal convergence rate is achieved by controlling the q‐function and the size of the extraction domain. Copyright © 2013 John Wiley & Sons, Ltd.
Utilization of silane functionalized carbon nanotubes‐silica hybrids as novel reinforcing fillers for solution styrene butadiene rubber
Authors: Wang Jingyi , Jia Hongbing , Ding Lifeng , Zhu Lijuan , Dai Xiu , Fei Xiang , Li Feng , Gong Xuedong
Published: April 2013

Carbon nanotubes‐silica (CNTs‐SiO2) nanohybrid filler was fabricated by coating inorganic silica on multi‐wall CNTs through a sol–gel process. The CNTs‐SiO2 nanohybrids were then functionalized by 3‐methacryloxypropyltrimethoxysilane (3‐MPTS) followed by compounding to solution styrene butadiene rubber (S‐SBR) through mechanical mixing. The Fourier‐transform infrared spectroscopy showed that the CNTs were coated by inorganic SiO2, and grafted with 3‐MPTS successfully. The functionalized CNTs‐SiO2 nanohybrids had a rough surface as revealed by transmission electron microscope images. After hybridization and grafting, the functionalized CNTs‐SiO2 nanohybrids still maintained the crystal structure of CNTs, which was determined by X‐ray diffraction and Raman spectrum. The addition of nanohybrids accelerated the vulcanization process and improved the crosslinking degree of vulcanizates. With adding 10 phr (parts per hundred of rubber) functionalized CNTs‐SiO2, the mechanical properties of S‐SBR vulcanizates were improved significantly. The tensile moduli at 100% elongation (M100) and tensile strength had 54% and 28% increase, respectively. The incorporation of functionalized CNTs‐SiO2 nanohybrids also largely enhanced the storage modulus, and slightly increased the thermal conductivity of vulcanizates. POLYM. COMPOS., 00:000–000, 2013. © 2013 Society of Plastics Engineers POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Reinforcement effect of biomass carbon and protein in elastic biocomposites
Authors: Jong Lei
Published: April 2013

Biomass carbon (BC) and soy protein (SP) were used to reinforce natural rubber (NR) biocomposites. The particle size of BC was reduced and characterized with elemental analysis, X‐ray diffraction, infrared spectroscopy, and particle size analysis. The rubber composite reinforced with the BC/SP and the composite reinforced with the BC of higher carbon content show useful tensile properties at an optimum filler fraction. The model analysis of the stress–strain behaviors provides insight into filler network characteristics. For the highly filled composites, the BC have less constraint on the polymer chains as shown by the temperature and frequency dependent modulus as well as the model analysis of stress softening effect. The presence of NR protein improves the filler–polymer adhesion for the composites reinforced with BC/SP. POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers
Relationship between the umbilical cord coiling index and the umbilical blood flow at 11–13 weeks of gestation
Authors: Hasegawa Junichi , Nakamura Masamitsu , Hamada Shoko , Matsuoka Ryu , Ichizuka Kiyotake , Sekizawa Akihiko , Okai Takashi
Published: April 2013

Objectives

The aim of this study was to clarify the effects of umbilical cord coiling on the umbilical blood flow at 11–13 weeks of gestation.

Methods

A cross‐sectional study was conducted among consecutive pregnant females at 11–13 weeks of gestation. Transabdominal ultrasound examinations were performed to obtain the umbilical coiling index (CI), the maximum umbilical arterial peak velocity at the free loop, the venous velocities at the free loop and the umbilical ring, and the umbilical arterial and venous flow volumes. After every measurement was standardized according to the crown‐rump length (CRL), correlations between the CI and these measurements were analyzed.

Results

A total of 364 subjects were enrolled. The CI significantly decreased in association with advancing gestation. There were significant correlations between the CRLs and the umbilical arterial peak velocities, the venous velocities at the free loop and the umbilical ring, and the umbilical arterial and venous flow volumes. The z‐scores of the umbilical arterial and venous velocimetries exhibited no significant correlations with the CI. The umbilical arterial and venous flow volumes were also not found to correlate with the CI.

Conclusions

The CI does not affect either the umbilical arterial or venous blood flow at 11–13 weeks of gestation. © 2013 John Wiley & Sons, Ltd.
Facile synthesis of high‐performance poly(pyrrolone imide)s from an unsymmetric phosphinated triamine
Authors: Lin Ching Hsuan , Li Chen Ming , Hsu Chin Kuang , Chang Hou Chien , Juang Tzong Yuan
Published: April 2013

High‐performance and flexible poly(pyrrolone imide)s (PPyIs) were firstly prepared by the reaction of dianhydrides with an unsymmetric phosphinated triamine, 1‐(3,4‐diaminophenyl)‐1‐(4‐aminophenyl)‐1‐(6‐oxido‐6H ‐dibenz  <1,2> oxaphosphorin‐6‐yl)ethane (1), which was prepared by a facile, one‐pot procedure from the reaction DOPO, 4‐aminoacetophenone in excess o‐phenylenediamine in the presence of p‐toluenesulfonic acid. Thermal properties of the resulting PPyIs were evaluated and compared with those of phosphinated polyimides with a similar structure. All of the prepared PPyIs films are tough and creasable. They display higher Tg (374–412 °C), lower coefficient of thermal expansion (34–46 ppm/°C), and better thermal stability (Td 5 wt %: 456–477 °C, 800 °C char yield: 59–63%) than analogous phosphinated polyimides. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2709–2715
Hydrophilic CO2‐based biodegradable polycarbonates: Synthesis and rapid thermo‐responsive behavior
Authors: Gu Lin , Qin Yusheng , Gao Yonggang , Wang Xianhong , Wang Fosong
Published: April 2013

Common CO2‐based biodegradable polycarbonates like poly(propylene carbonate) or poly(cyclohexene carbonate) are generally hydrophobic, leading to slow biodegradation rate and poor cell adhesion, which limit their applications in the biomedical field. Here hydrophilic polycarbonates were prepared by one‐pot terpolymerization of CO2, propylene oxide (PO), and 2‐((2‐(2‐(2‐methoxyethoxy)ethoxy)ethoxy)methyl)oxirane (ME3MO) using binary Salen Co(III)‐Cl/PPNCl catalyst system. The resultant terpolymers showed one glass transition temperature (Tg), which decreased with the increase of ME3MO units in the terpolymers (FME3MO). Water contact angles of the resultant terpolymers with FME3MO of 4.2−23.6% were 68−25°, while that of poly(propylene carbonate) was 90°, indicating that the terpolymers became hydrophlilic. Furthermore, the terpolymers with FME3MO more than 25.8% exhibited reversible and rapid thermo‐responsive property in water, and the lower critical solution temperature (LCST) was highly sensitive to FME3MO. In particular, aqueous solution of the terpolymer with FME3MO of 72.6% showed a LCST around 35.2 °C, close to body temperature, which was promising for biomedical applications, especially for in vivo applications. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2834–2840.
Groundwater Hydrology and Stable Isotope Analysis of an Open‐System Pingo in Northwestern Mongolia
Authors: Yoshikawa Kenji , Sharkhuu Natsagdorj , Sharkhuu Anarmaa
Published: April 2013

The first record of stable isotopes through a complete sequence of ice within an open‐system pingo in northwestern Mongolia indicates a complex history of ice formation and pingo growth. A continuous section of ice 32 m long was cored through the centre of Mongot Pingo, and ice cores were analysed for stable isotopes and chemical composition. Two different stable isotope patterns in separate ice sections are identified: 1 open‐system freezing and 2 semi‐closed system (or closed system) freezing. Discharge measurements were observed in 2009 after drilling through pingo ice to artesian sub‐pingo water and compared with data collected from the same pingo in 1968. Approximately 850–950 m3 of sub‐pingo water discharged within 120 h during drilling in both 1968 and 2009, a volume equivalent to about 10 per cent of the current pingo ice volume. Between 1968 and 2009, permafrost (pingo ice) thickened by about 60 cm (1.46 cm per year), from 32.0 to 32.6 m, due to the decrease in sub‐pingo artesian water pressure after water release from the 1968 drilling. The major mechanism for ice formation at this pingo is groundwater artesian pressure, though not continuously. Four major stages of pingo growth after 8790 yr BP are inferred. Copyright © 2013 John Wiley & Sons, Ltd.
A decade and a half of protein intrinsic disorder: Biology still waits for physics
Authors: Uversky Vladimir N.
Published: April 2013

The abundant existence of proteins and regions that possess specific functions without being uniquely folded into unique 3D structures has become accepted by a significant number of protein scientists. Sequences of these intrinsically disordered proteins (IDPs) and IDP regions (IDPRs) are characterized by a number of specific features, such as low overall hydrophobicity and high net charge which makes these proteins predictable. IDPs/IDPRs possess large hydrodynamic volumes, low contents of ordered secondary structure, and are characterized by high structural heterogeneity. They are very flexible, but some may undergo disorder to order transitions in the presence of natural ligands. The degree of these structural rearrangements varies over a very wide range. IDPs/IDPRs are tightly controlled under the normal conditions and have numerous specific functions that complement functions of ordered proteins and domains. When lacking proper control, they have multiple roles in pathogenesis of various human diseases. Gaining structural and functional information about these proteins is a challenge, since they do not typically “freeze” while their “pictures are taken.” However, despite or perhaps because of the experimental challenges, these fuzzy objects with fuzzy structures and fuzzy functions are among the most interesting targets for modern protein research. This review briefly summarizes some of the recent advances in this exciting field and considers some of the basic lessons learned from the analysis of physics, chemistry, and biology of IDPs.
Toward indium‐free optoelectronic devices: Dielectric/metal/dielectric alternative transparent conductive electrode in organic photovoltaic cells
Authors: Cattin L. , Bernède J. C. , Morsli M.
Published: April 2013

Depending on their resistivity and their transmittance, the thin films of transparent conductive oxide (TCO) are widely used in optoelectronic devices. In2O3:Sn (ITO) is the most widely used TCO in optoelectronic devices. As indium is scarce and ITO is limited in flexibility due to its ceramic structure, many studies have been dedicated to new transparent conductive electrodes. This review article presents the state‐of‐the‐art concerning the dielectric/metal/dielectric structures and their application as transparent electrodes in organic photovoltaic cells (OPVCs). First, TCO/Ag/TCO structures were created to achieve higher conductivity than ITO films. Then others dielectrics have been used such as transition‐metal oxides (WO3, MoO3, V2O5, etc.), ZnS, etc. Such structures exhibit excellent flexibility, high conductivity, and good transparency. They can be deposited onto substrates at room temperature by simple evaporation under vacuum. Moreover, it is possible to manage the anode work function through the choice of the dielectric, which can allow them to be used as cathodes or anodes and as intermediate electrodes in tandem solar cells. The properties of the dielectric/metal/dielectric (D/M/D) structures depend on the thickness of the different layers. The threshold thickness value of the metal film is usually around 10 nm, where the structures change from an insulating state to a highly conductive state. This is attributed to the percolation of conducting metal paths. The transmittance of the films increases when the metal thickness increases up to the percolation thickness, while further increase induces a decrease in transmittance. Finally, the nature and the thickness of the dielectric layers can be chosen as a function of the device properties requested, which is illustrated through different examples of OPVCs.
Local N environment in the dilute nitrides Ga(N,P), Ga(N,As), and Ga(N,Sb)
Authors: Güngerich M. , Sander T. , Heiliger C. , Czerner M. , Klar P. J.
Published: April 2013

We study the hydrostatic pressure response of the local environment of N in the ternary dilute nitride alloys, i.e., GaN0.021P0.979, GaN0.085As0.915, and GaN0.015Sb0.985 by Raman spectroscopy and density functional theory (DFT) of the local vibrational mode (LVM) of N. In all samples studied N is surrounded by four Ga atoms. To a first approximation the N vibrational mode can be described by the N‐atom vibrating in a rigid cage formed by the four Ga nearest neighbors. However, our careful experimental and theoretical analysis reveals that, despite the same nearest neighbor environment of N in the three dilute nitride hosts under study, distinct differences between the pressure dependence of the corresponding local N‐vibrational modes remain. These differences are rather due to the different chemical identities of the anions of the host than due to differences in N content and strain. Furthermore, it is shown that the LVM of N in the three alloys behaves differently under hydrostatic pressure than the optical extended phonon modes of zincblende GaN.
Iron in magnesium oxide at high pressures: a first principles theoretical investigation
Authors: Larico Rolando , Justo João F. , Assali Lucy V. C.
Published: April 2013

An iron‐related high‐to‐low spin transition in ferropericlase, (MgFe)O, has been identified at high pressures. Since this is one of the major minerals of Earth's lower mantle, and the respective transition occurs at mantle pressure and temperature conditions, this transition could have important geophysical implications. Here, we performed a theoretical investigation on the properties of a substitutional iron impurity in magnesium oxide, (MgO: FeMg), and the respective changes with increasing isotropic pressure. This microscopic configuration represents the limiting case of absent iron–iron interactions in ferropericlase, which allowed us to explore the magnetic properties of the isolated iron center. The calculations were performed using the WIEN2k package, within the density functional theory plus a Hubbard potential correction. The structural, electronic, and magnetic properties of those centers at several charge states and pressures (up to 100 GPa) were compared. We also discussed the possibility of an iron‐related intermediate spin (IS) state in ferropericlase. Our results on the quadrupole splitting indicate that such IS state should have properties similar to the respective spin state in ferrosilicate perovskite.
Pressure effect on the anomalies of the electric and magnetic properties of diluted magnetic semiconductor CdGeAs2 doped with Mn
Authors: Arslanov Rasul , Mollaev Akhmedbek , Kamilov Ibragimkhan , Arslanov Temirlan , Zalibekov Ullubiy , Novotortsev Vladimir , Marenkin Sergey , Troyanchuk Igor
Published: April 2013

This paper presents the results of the high pressure (up to 7 GPa) effect on the diluted magnetic semiconductor (DMS) CdGeAs2: Mn with x = 0.06–030. The normal R0 and anomalous RS portions of the Hall coefficients have been determined from the magnetic field dependencies of the Hall resistance. Pressure ranges related to the anomalies of the electric and magnetic properties have been found and studied. It has been shown that structural phase transitions are observed on the baric dependencies and their transition point shifts depending on the Mn content.

The first‐ and second‐order phase transitions (ferromagnetic–paramagnetic and paramagnetic–paramagnetic) have been identified on the magnetic susceptibility dependence in the pressure areas of P > 1.3 GPa and P ≈ 4 GPa which can be explained by occurrence of the second phase of MnAs in the basic structure of CdGeAs2. Positive (PMR) and negative magnetoresistance (NMR) induced by high pressure also takes place in all the compounds studied.
High‐pressure study of the thermoelectric properties of various oxides (ZnO, Ti2O3, FexOy) and FeAs‐based compounds
Authors: Morozova Natalia V. , Khmeleva Iuliia A. , Ovsyannikov Sergey V. , Karkin Alexander E. , Shchennikov Vladimir V.
Published: April 2013

In the present work the results of investigation of the thermoelectric (TE) properties of some Zn, Ti and Fe oxides and FeAs‐based compounds under compression up to 20 GPa are reported. The data obtained of thermoelectric power S dependence on pressure P for the materials under consideration revealed some new features of the electron properties of both initial and high‐pressure phases (RS‐ZnO). For FeAs‐based compounds the complex behavior of S on P was found depending probably on the contribution of d‐states in the conductivity. The decreasing of the semiconductors gap has been established under pressure for the narrow‐gap semiconductors Ti2O3 and Fe2O3; the sign inversion being observed in the first oxide pointing to the change of dominant type of the charge carries. Pressure cycling of Fe2O3 led to a nanostructured state with the modified electronic properties. TE data at high pressure allowed the electronic properties of the materials with the different type of the electron structure to be detailed.
Rashba spin–orbit interaction effect on multiphoton optical transitions in a quantum dot
Authors: Kumar Manoj , Lahon Siddhartha , Kumar Jha Pradip , Mohan Man
Published: April 2013

We demonstrate in this work the effect of Rashba spin–orbit interaction (SOI) on multiphoton optical transitions of a quantum dot (QD) in the presence of a terahertz (THz) laser field and external static magnetic field. This combination is solved by accurate nonperturbative Floquet theory. Investigations are made for the optical response of intraband transitions between the various states of the conduction band with spin flipping. It is found that spin‐flip transitions and corresponding multiphoton transitions are strongly affected by Rashba spin orbit coupling and THz laser fields. This aspect will enhance the ongoing efforts for making ultrasensitive optospintronics devices.
Magnetic phase transition and relaxation effects in lithium iron phosphate
Authors: Sundarayya Y. , Mishra Ajay Kumar , Brand Richard A. , Hahn Horst , Bansal C. , Sunandana C. S.
Published: April 2013

We report the observation of a para‐antiferromagnetic transition at ∼50 K in lithium iron phosphate, LiFePO4 through DC magnetic susceptibility and Mössbauer spectroscopy. The ferrous ion Fe2+ (3d6, 5D) in LiFePO4 exhibits relaxation effects with a relaxation frequency ∼1.076 × 107 s−1 at 300 K. The temperature dependence of the frequency suggests the origin of the relaxation is of the spin–lattice type. The quadrupole splitting at low temperatures indicates that the excited orbital states mix strongly to the orbital doublet ground state via spin–orbit coupling. Modified molecular field model analysis yields a saturation value for hyperfine field Bhf ∼ 125 kOe. The anomaly in susceptibility and Mössbauer parameters below 27 K may be ascribed to a contribution of orbital angular momentum. The high value of the asymmetry parameter η (∼0.8) of the electric field gradient obtained in the antiferromagnetic regime indicates a strongly distorted octahedral oxygen neighborhood for the ferrous sites.
WATER TEMPERATURE PATTERNS BELOW LARGE GROUNDWATER SPRINGS: MANAGEMENT IMPLICATIONS FOR COHO SALMON IN THE SHASTA RIVER, CALIFORNIA
Authors: Nichols A. L. , Willis A. D. , Jeffres C. A. , Deas M. L.
Published: April 2013

Elevated stream temperature is a primary factor limiting the coho salmon (Oncorhynchus kisutch) population in California's Shasta River Basin. Understanding the mechanisms driving spatial and temporal trends in water temperature throughout the Shasta River is critical to prioritising river restoration efforts aimed at protecting this threatened species. During the summer, the majority of streamflow in the Shasta River comes from large‐volume, cold‐water springs at the head of the tributary Big Springs Creek. In this study, we evaluated the initial character of this spring water, as well as the downstream fate and transport of these groundwater inflows during July and August 2008. Our results indicated that Big Springs Creek paradoxically provided both cool and warm waters to the Shasta River. During this period, cool groundwater inflows heated rapidly in the downstream direction in response to thermal loads from incoming solar radiation. During the night time, groundwater inflows did not appreciably heat in transit through Big Springs Creek. These diurnally varying water temperature conditions were inherited by the Shasta River, producing longitudinal temperature patterns that were out of phase with ambient meteorological conditions up to 23 km downstream. Findings from this study suggest that large, constant temperature spring sources and spring‐fed rivers impart unique stream temperature patterns on downstream river reaches that can determine reach‐scale habitat suitability for cold‐water fishes such as coho salmon. Recognising and quantifying the spatiotemporal patterns of water temperature downstream from large spring inflows can help identify and prioritize river restoration actions in locations where temperature patterns will allow rearing of cold‐water fishes. Copyright © 2013 John Wiley & Sons, Ltd.