bluuebunny/crossref_metadata_2025 huggingface dataset:
Laparoscopic radiofrequency ablation for the management of colorectal liver metastases: 10‐year experience
Authors: Kennedy Timothy J. , Cassera Maria A. , Khajanchee Yashodhan S. , Diwan Tayyab S. , Hammill Chet W. , Hansen Paul D.
Published: September 2012

Background

Published results addressing the treatment of colorectal liver metastases (CRLM) with radiofrequency ablation (RFA) vary widely with local recurrence rates of 2–40% and 5‐year survival of 14–55%. The goal of this study was to analyze our 10‐year experience with laparoscopic RFA.

Methods

From January 2000 to July 2010, 130 patients underwent laparoscopic RFA for CRLM. Kaplan–Meier analysis was used to assess survival. Univariate and multivariate analysis were performed to identify factors associated with survival and recurrence.

Results

In this cohort, median survival was 40.4 months with 5‐year survival of 28.8%. Overall, 9.2% of patients had a local recurrence (3.6% for tumors 3 cm or less). On univariate analysis, factors associated with decreased survival were BMI (P = 0.045), rectal primary (P = 0.005), and increased tumor size (P = 0.002). On multivariate analysis, increased tumor size (HR 1.29 [95% CI: 1.04–1.59]; P = 0.020) and bilobar disease (HR 2.06 [95% CI: 1.02–4.15]; P = 0.044) were associated with decreased survival. On univariate analysis, only BMI was found to be associated with disease recurrence (P = 0.025).

Conclusions

Our data demonstrate that laparoscopic RFA can achieve a median survival of 40.4 months with a low local recurrence rate. Patients with tumors 3 cm or less have a decreased risk of local recurrence. J. Surg. Oncol. 2013;107:324–328. © 2012 Wiley Periodicals, Inc.
Blood neutrophil‐to‐lymphocyte ratio correlates with tumor size in patients with differentiated thyroid cancer
Authors: Liu Chien‐Liang , Lee Jie‐Jen , Liu Tsang‐Pai , Chang Yuan‐Ching , Hsu Yi‐Chiung , Cheng Shih‐Ping
Published: September 2012

Background and Objectives

Inflammation has been implicated in the initiation and progression of thyroid cancer. Neutrophil‐to‐lymphocyte ratio (NLR) is a simple index of systemic inflammatory response, and has been shown to be a prognostic indicator in some types of cancer. The aim of this study was to examine the relationship between NLR and clinicopathological features in patients with differentiated thyroid cancer.

Methods

Total white blood cell and differential counts of 159 patients with differentiated thyroid cancer were compared to those of 318 age‐ and sex‐matched controls undergoing thyroidectomy for benign thyroid nodules. Clinicopathological variables, stratified by NLR tertiles, were analyzed.

Results

There was no difference in NLR between patients having benign and malignant thyroid nodules (P = 0.293). Cancer patients in the higher NLR tertile had significantly larger tumor size (P = 0.004). Higher NLR was observed in patients with high American Thyroid Association (ATA) risk of recurrence.

Conclusions

High preoperative NLR was associated with increased tumor size and high ATA risk of recurrence in patients with differentiated thyroid cancer. J. Surg. Oncol. 2013;107:493–497. © 2012 Wiley Periodicals, Inc.
Removal of cefalexin using yeast surface‐imprinted polymer prepared by atom transfer radical polymerization
Authors: Li Xiuxiu , Pan Jianming , Dai Jiangdong , Dai Xiaohui , Ou Hongxiang , Xu Longcheng , Li Chunxiang , Zhang Rongxian
Published: September 2012

The first use of yeast as a support in the molecular imprinting field combined with atom transfer radical polymerization was described. Then, the as‐prepared molecularly imprinted polymers were characterized by Fourier transmission infrared spectrometry, scanning electron microscope, thermogravimetric analysis, and elemental analysis. The obtained imprinted polymers demonstrated elliptical‐shaped particles with the thickness of imprinting layer of 0.63 μm. The batch mode experiments were adopted to investigate the adsorption equilibrium, kinetics, and selectivity. The kinetic properties of imprinted polymers were well described by the pseudo‐second‐order kinetic equation, indicating the chemical process was the rate‐limiting step for the adsorption of cefalexin (CFX). The equilibrium data were well fitted by the Freundlich isotherm, and the multimolecular layers adsorption capacity of imprinted polymers was 34.07 mg g−1 at 298 K. The selectivity analysis suggested that the imprinted polymers exhibited excellent selective recognition for CFX in the presence of other compounds with related structure. Finally, the analytical method based on the imprinted polymers extraction coupled with high‐performance liquid chromatograph was successfully used for CFX analysis in spiked pork and water samples.
Fabrication of microcellular polymer/graphene nanocomposite foams
Authors: Shen Bin , Zhai Wentao , Lu Dingding , Zheng Wenge , Yan Qing
Published: September 2012

Graphene has recently gained revolutionary aspirations because of its remarkable electronic, thermal and mechanical properties. These unique properties make it promising for preparing multifunctional nanocomposites. In recent years, polymer foams based on graphene have also received increasing attention in both the scientific and industrial communities. This review presents an overview of polymer/graphene nanocomposite foams discussing the production of graphene, the polymer functionalization of graphene and different polymer/graphene foams with different properties. One of the most promising avenues is to fabricate tough and lightweight materials with superior electrical and electromagnetic interference shielding properties. Copyright © 2012 Society of Chemical Industry
Thin‐film polycrystalline silicon solar cells formed by diode laser crystallisation
Authors: Dore Jonathon , Evans Rhett , Schubert Ute , Eggleston Bonne D. , Ong Daniel , Kim Kyung , Huang Jialiang , Kunz Oliver , Keevers Mark , Egan Renate , Varlamov Sergey , Green Martin A.
Published: September 2012

Polycrystalline silicon films of 10 μm thickness are formed on glass in a single‐step continuous wave diode laser crystallisation process, creating large crystal grains up to 1 mm wide and 10 mm long. Solar cells are formed on the layers by employing a rear point contacting scheme. Intermediate layers between the glass and the silicon are shown to heavily influence the cell characteristics. A stack of silicon oxide/silicon nitride/silicon oxide has produced the best cell efficiency so far of 8.4 % with open‐circuit voltage of 557 mV. With simple optimisation of the contacting scheme, 10 % efficient cells are expected in the near future. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis and structure–conductivity relationship of polystyrene‐block‐poly(vinyl benzyl trimethylammonium) for alkaline anion exchange membrane fuel cells
Authors: Tsai Tsung‐Han , Maes Ashley M. , Vandiver Melissa A. , Versek Craig , Seifert Sönke , Tuominen Mark , Liberatore Matthew W. , Herring Andrew M. , Coughlin E. Bryan
Published: September 2012

Block copolymers of polystyrene‐b‐poly(vinyl benzyl trimethylammonium tetrafluoroborate) (PS‐b‐[PVBTMA][BF4]) were synthesized by sequential monomer addition using atom transfer radical polymerization. Membranes of the block copolymers were prepared by drop casting from dimethylformamide. Initial evaluation of the microphase separation in these PS‐b‐[PVBTMA][BF4] materials via SAXS revealed the formation of spherical, cylindrical, and lamellar morphologies. Block copolymers of polystyrene‐b‐poly(vinyl benzyl trimethylammonium hydroxide) (PS‐b‐[PVBTMA][OH]) were prepared as polymeric alkaline anion exchange membranes materials by ion exchange from PS‐b‐[PVBTMA][BF4] with hydroxide in order to investigate the relationship between morphology and ionic conductivity. Studies of humidity [relative humidity (RH)]‐dependent conductivity at 80 °C showed that the conductivity increases with increasing humidity. Moreover, the investigation of the temperature‐dependent conductivity at RH = 50, 70, and 90% showed a significant effect of grain boundaries in the membranes against the formation of continuous conductive channels, which is an important requirement for achieving high ion conductivity. © 2012 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2013, 51, 1751–1760, 2013
On adaptive sliding mode control without switching gain overestimation
Authors: Cong B.L. , Chen Z. , Liu X.D.
Published: September 2012

This paper presents some further results on adaptive sliding mode control (ASMC) for a class of nonlinear systems with bounded uncertain parameters. Given a large initial tracking error, current ASMC design generally produces an unnecessarily large switching gain, consequently leading to a serious chattering problem or a large‐amplitude control jump for the continuous counterpart. To solve such an overadaptation problem, the switching gain adaptation mechanism is first analyzed in this paper, and the adaptation induced by the initial tracking error is suggested to be removed. Then, by exploiting the global sliding mode feature of time‐varying sliding mode control and integral sliding mode control, we present two effective methodologies for ASMC design. The proposed ASMC algorithms ensure that there is no overestimation of the switching gain and the system response is not slowed down when a small switching gain is generated. The validity of the proposed methods is verified by both theoretical analysis and simulation results. Copyright © 2012 John Wiley & Sons, Ltd.
Exponential H ∞  filtering for stochastic Markovian jump systems with time delays
Authors: Chen Yun , Zheng Wei Xing
Published: September 2012

This paper investigates the problem of exponential H ∞  filtering for stochastic systems with time delays and Markovian jumping parameters. On the basis of Lyapunov–Krasovskii functional theory and generalized Finsler lemma, a delay‐dependent bounded real lemma is established without using any model transformations, bounding techniques for cross terms, or additional free matrix variables. The obtained bounded real lemma guarantees that the filtering error system is both mean‐square exponentially stable and almost surely exponentially stable with a prescribed H ∞  noise attenuation level. Then an exponential H ∞  filter is designed for stochastic retarded Markovian jump systems in terms of a set of LMIs. Meanwhile, the mathematical equivalence of the proposed method to one recent method is presented, but our proposed method is more computationally efficient with fewer matrix variables than that recent method. The validity of the method is verified by a numerical example.Copyright © 2012 John Wiley & Sons, Ltd.
18F‐FDG Uptake at Initial Staging of the Adrenocortical Cancers: A Diagnostic Tool but Not of Prognostic Value
Authors: Tessonnier L. , Ansquer C. , Bournaud C. , Sebag F. , Mirallié E. , Lifante J. C. , Palazzo F. F. , Morange I. , Drui D. , de la Foucardère C. , Mancini J. , Taïeb D.
Published: September 2012

Background

Adrenocortical carcinoma (ACC) is a rare cancer for which little level evidence exists to guide management. 18F‐FDG PET (18F‐fluorodeoxyglucose positron emission tomography) is an increasingly used diagnostic tool in patients with suspicious or indeterminate adrenal tumors. In some other solid tumors, 18F‐FDG PET may offer prognostic information that can guide optimal patient treatment. The aim of the present study was to evaluate whether preoperative 18F‐FDG PET based on SUVs assessments has a prognostic value in ACC patients.

Methods

A retrospective analysis was performed in patients who underwent 18F‐FDG PET/CT for the evaluation of ACC. Inclusion criteria were an unequivocal diagnosis of ACC; all data from primary diagnosis available; 18F‐FDG PET/CT performed prior to surgery or other treatment of the primary tumor; a minimum of 6‐months follow‐up for surviving patients. All 18F‐FDG PET/CT procedures were reinterpreted in a blind fashion.

Results

Thirty‐seven patients (23 without metastasis [M0], 14 with metastasis [M1]) fulfilled the study criteria. Median uptake values were tumor standardized uptake values (SUV)max = 11 (range: 3–56) and a tumor/liver SUVmax ratio = 4.2 (range: 1.3–15). Median follow‐up was 20 months. Although classic risk factors (tumoral stage, Weiss score) were associated with poor outcome, there was no correlation between primary tumor FDG uptake with overall survival (OS) and disease free survival (DFS) in M0 patients and with overall survival in M1 patients. 18F‐FDG uptake correlated inconsistently with sinister histological features, such as atypical mitoses or necrosis.

Conclusions

At initial staging, primary tumor FDG uptake in ACC patients does not correlate with OS and DFS at 2 years. Patient prognosis and treatment strategy should not be based on uptake values.
Social Correlates of Church Attendance in Three European Catholic Countries
Authors: Conway Brian
Published: September 2012

The sociology of religion literature recognizes secularization as an uneven process complicated by individual and country-level variables. However, considerably less attention has been given to how correlates of church attendance vary across divergent settings within a single religious denomination. Employing recent data from Belgium, Ireland, and Slovenia, we test whether the belief, ideological support for the church, and religious commitment correlates of religious behaviour are similar across these Catholic countries and whether there are any remaining country effects influencing church attendance. The results of ordered logit regression models show, on the one hand, the correlates of church attendance are basically the same across the three countries and, on the other, that country effects remain even when controlling for the key explanatory variables and other covariates. These empirical findings suggest the need to develop a more contextual-based understandings of secularization, focusing on the influence of cultural factors operative in nationally-specific settings.
Swept wing boundary-layer receptivity to localized surface roughness
Authors: Tempelmann David , Schrader Lars-Uve , Hanifi Ardeshir , Brandt Luca , Henningson Dan S.
Published: September 2012

The receptivity to localized surface roughness of a swept-wing boundary layer is studied by direct numerical simulation (DNS) and computations using the parabolized stability equations (PSEs). The DNS is laid out to reproduce wind tunnel experiments performed by Saric and coworkers, where micron-sized cylinders were used to trigger steady crossflow modes. The amplitudes of the roughness-induced fundamental crossflow wave and its superharmonics obtained from nonlinear PSE solutions agree excellently with the DNS results. A receptivity model using the direct and adjoint PSEs is shown to provide reliable predictions of the receptivity to roughness cylinders of different heights and chordwise locations. Being robust and computationally efficient, the model is well suited as a predictive tool of receptivity in flows of practical interest. The crossflow mode amplitudes obtained based on both DNS and PSE methods are 40 % of those measured in the experiments. Additional comparisons between experimental and PSE data for various disturbance wavelengths reveal that the measured disturbance amplitudes are consistently larger than those predicted by the PSE-based receptivity model by a nearly constant factor. Supplementary DNS and PSE computations suggest that possible natural leading-edge roughness and free-stream turbulence in the experiments are unlikely to account for this discrepancy. It is more likely that experimental uncertainties in the streamwise location of the roughness array and cylinder height are responsible for the additional receptivity observed in the experiments.
The structure of zonal jets in geostrophic turbulence
Authors: Scott Richard K. , Dritschel David G.
Published: September 2012

The structure of zonal jets arising in forced-dissipative, two-dimensional turbulent flow on the $\ensuremath{\beta} $-plane is investigated using high-resolution, long-time numerical integrations, with particular emphasis on the late-time distribution of potential vorticity. The structure of the jets is found to depend in a simple way on a single non-dimensional parameter, which may be conveniently expressed as the ratio ${L}_{\mathit{Rh}} / {L}_{\varepsilon } $, where ${L}_{\mathit{Rh}} = \sqrt{U/ \ensuremath{\beta} } $ and ${L}_{\varepsilon } = \mathop{ (\varepsilon / {\ensuremath{\beta} }^{3} )}\nolimits ^{1/ 5} $ are two natural length scales arising in the problem; here $U$ may be taken as the r.m.s. velocity, $\ensuremath{\beta} $ is the background gradient of potential vorticity in the north–south direction, and $\varepsilon $ is the rate of energy input by the forcing. It is shown that jet strength increases with ${L}_{\mathit{Rh}} / {L}_{\varepsilon } $, with the limiting case of the potential vorticity staircase, comprising a monotonic, piecewise-constant profile in the north–south direction, being approached for ${L}_{\mathit{Rh}} / {L}_{\varepsilon } \ensuremath{\sim} O(10)$. At lower values, eddies created by the forcing become sufficiently intense to continually disrupt the steepening of potential vorticity gradients in the jet cores, preventing strong jets from developing. Although detailed features such as the regularity of jet spacing and intensity are found to depend on the spectral distribution of the forcing, the approach of the staircase limit with increasing ${L}_{\mathit{Rh}} / {L}_{\varepsilon } $ is robust across a variety of different forcing types considered.
Guinea's Political Prisoners: Colonial Models, Postcolonial Innovation
Authors: MacDonald Mairi S.
Published: September 2012

Much postcolonial theory assumes a continuity of both behavior and representation between colonial rule and what has succeeded it across sub-Saharan Africa. The maltreatment of political prisoners in Guinea in the wake of its brief invasion by Portuguese troops in November 1970 provides a challenging but ultimately fruitful empirical record against which to test this theory. I use an analytical approach informed by history, law, anthropology, and communications theory to explore continuities between the legal practices of French colonial and contemporary revolutionary regimes, on one hand, and Guinea's pursuit of supposed traitors, on the other. Though there is more discontinuity than direct inheritance in the administration of justice, the article argues that the representation of Guinea's colonial heritage was a central part of how President Sékou Touré legitimized his state and his own rule. I suggest that the colonial legacy operated more as a benchmark of what behavior might be acceptable in a postcolonial revolutionary state such as Guinea than as a linear precedent from French colonial rule to the Guinean revolution. The regime's representation of its colonial legacy also helps to explain the form, medium, and content of the political prisoners' broadcast confessions.
Geological history of bathyal echinoid faunas, with a new genus from the late Cretaceous of Italy
Authors: SMITH ANDREW B.
Published: September 2012

The Scaglia Rossa of central and northern Italy yields a late Cretaceous bathyal echinoid fauna. Comparison with Jurassic and Cenozoic bathyal faunas highlights that (i) there have been at least three phases of colonization of bathyal settings from the continental shelves, with successive faunas replacing the earlier; and (ii) bathyal echinoid faunas encompass an increasing range of feeding strategies and greater diversity of taxa through time, paralleling increasing nutrification of the oceans. A new Santonian deep-sea spatangoid,Bathyovulaster disjunctusgen. et sp. nov., is described from sediments deposited at > 1500 m water depth at Gubbio, Umbria–Marche region, Italy.
SHORTENED PEGINTERFERON AND RIBAVIRIN TREATMENT FOR CHRONIC HEPATITIS C
Authors: Hartwell Debbie , Jones Jeremy , Baxter Louise , Shepherd Jonathan
Published: September 2012

Background: Peginterferon alfa and ribavirin combination therapy is an effective treatment for many patients with chronic hepatitis C virus (HCV). Reducing the length of treatment may be advantageous. We performed a systematic review and economic evaluation to assess shorter treatment duration of this regimen.

Methods: We searched fourteen bibliographic databases (including The Cochrane Library, Medline, and Embase) from 2000 to October 2009 and consulted experts and drug manufacturers. Eligible articles were randomized controlled trials (RCTs) selected according to predefined criteria. We undertook an economic evaluation to assess the cost-effectiveness of shortened treatment versus standard treatment in the UK.

Results: Six trials were included. In the sub-group of patients who had low viral load (LVL) and a rapid virological response (RVR), there were no statistically significant differences in sustained virological response (SVR) rates between patients who received standard treatment (range, 83 percent to 100 percent) and those who received shortened courses (range 84 percent to 96 percent) (24 weeks for genotype 1, 16 weeks for genotype 2/3). Shortened treatment resulted in cost savings, but in some scenarios also resulted in poorer outcome, compared with standard treatment. This requires a judgment to be made on the value of the quality-adjusted life-year loss resulting from adopting a shorter treatment regimen, if shorter treatment is associated with a lower SVR than standard treatment duration.

Conclusions: For chronic HCV patients who have LVL and achieve an RVR, shortened peginterferon and ribavirin combination therapy could be considered as a viable treatment option.
The usefulness of brain natriuretic peptide in simple congenital heart disease – a systematic review
Authors: Eindhoven Jannet A. , van den Bosch Annemien E. , Boersma Eric , Roos-Hesselink Jolien W.
Published: September 2012

Brain natriuretic peptide and N-terminal pro-brain natriuretic peptide are two well-established markers for cardiac failure in acquired heart disease. Nevertheless, the clinical utility of these markers in patients with congenital heart disease remains unclear. Therefore, the aim of this study was to evaluate the diagnostic and prognostic value of these markers in patients with congenital heart disease. A PubMed and EMBASE literature search was executed with focus on the most common simple congenital heart defects, atrial septal defect and ventricular septal defect. Data on brain natriuretic peptide measurement, cardiac function parameters, and follow-up were collected. In patients with atrial or ventricular septal defect, brain natriuretic peptide levels were mildly increased when compared with healthy age-matched controls. Shunt severity and pulmonary artery pressure correlated strongly with natriuretic peptide levels. A clear association between brain natriuretic peptide and functional class was demonstrated. After closure of the defect, a rise in brain natriuretic peptide levels in the first hours to days was observed. After longer follow-up, natriuretic peptide levels decreased and became comparable to pre-procedural values. In conclusion, this systematic review shows that brain natriuretic peptide levels are mildly increased in patients with unrepaired and repaired atrial or ventricular septal defect. Brain natriuretic peptide measurement might be a useful additional tool in the diagnostic work-up of patients with atrial or ventricular septal defect. Further investigation in a larger, prospective study with long-term follow-up is warranted to elucidate the true prognostic value of natriuretic peptides in patients with simple congenital heart disease.
Impaired Awareness of Deficits in Alzheimer's Disease: The Role of Everyday Executive Dysfunction
Authors: Amanzio Martina , Vase Lene , Leotta Daniela , Miceli Renato , Palermo Sara , Geminiani Giuliano
Published: September 2012

The present study analyzed the awareness of deficits in 117 mild Alzheimer's disease participants. Since few studies have examined the cognitive and behavioral domains of reduced awareness in detail, we performed a domain-specific assessment using the Awareness of deficit Questionnaire – Dementia scale with the novel aim of describing the relationship with everyday executive dysfunction. Through the use of the subtests of the Behavioral Assessment of the Dysexecutive Syndrome, we hypothesized that executive cognitive functions may play an important role in the reduced awareness of deficits. We also considered other variables of interest to provide a novel comprehensive explanation of this phenomenon. Our first approach to the study was a factor analysis considering the role of these variables in the awareness of deficits; subsequently, regression analysis models were used to define which variables were associated with a reduction of awareness in cognitive and behavioral domains. In particular, the factors retained from the factor analysis, in terms of inhibition, self-monitoring, set-shifting, and mood orientation changes, appear to be important skills for awareness of instrumental activities of daily living (R2= .32). We also found hypo manic mood orientation and a tendency through apathy to be prominent indications of reduced behavioral awareness (R2= .13). (JINS, 2013,18, –)
School feeding, moving from practice to policy: reflections on building sustainable monitoring and evaluation systems
Authors: Gelli Aulo , Espejo Francisco
Published: September 2012

Objective

To provide an overview of the status of monitoring and evaluation (M&E) of school feeding across sub-Saharan Africa and to reflect on the experience on strengthening M&E systems to influence policy making in low-income countries.

Design

Literature review on the M&E of school feeding programmes as well as data from World Food Programme surveys.

Setting

Sub-Saharan Africa.

Subjects

Countries implementing school feeding.

Results

Only two randomized controlled impact evaluations have been implemented in sub-Saharan Africa. Where M&E data collection is underway, the focus is on process and service delivery and not on child outcomes. M&E systems generally operate under the Ministry of Education, with other Ministries represented within technical steering groups supporting implementation. There is no internationally accepted standardized framework for the M&E of school feeding. There have been examples where evidence of programme performance has influenced policy: considering the popularity of school feeding these cases though are anecdotal, highlighting the opportunity for systemic changes.

Conclusions

There is strong buy-in on school feeding from governments in sub-Saharan Africa. In response to this demand, development partners have been harmonizing their support to strengthen national programmes, with a focus on M&E. However, policy processes are complex and can be influenced by a number of factors. A comprehensive but simple approach is needed where the first step is to ensure a valid mandate to intervene, legitimizing the interaction with key stakeholders, involving them in the problem definition and problem solving. This process has been facilitated through the provision of technical assistance and exposure to successful experiences through South–South cooperation and knowledge exchange.
Oswin Boys Bull and the Emergence of Southern African ‘Nonwhite’ YMCA Work
Authors: Anthony David
Published: September 2012

From 1908 to 1922, Oswin Boys Bull (1882–1971) had the primary responsibility for supervising the recruitment of African youth and students into the South African SCA and YMCA. Following the lead of overseas sojourners Luther Wishard and Donald Fraser in 1895 and John R. Mott and Ruth Rouse in 1906, Bull took his experience as a Jesus College, Cambridge classics and theology major and sportsperson into the challenging religious, racial and ethnic field of the Union of South Africa. Bringing a mix of strong spiritual roots and an unwavering commitment to the racially inclusive interpretation of Christianity, Bull blazed a trail that earned him the reputation of a pioneer ecumenist.

Ably assisted by illustrious Xhosa-speaking intellectual and seasoned Christian proselytizer John Knox Bokwe, Bull made inroads into areas previously ignored by his predecessors. With a reach extending as far as neighboring historic Basutoland, Bull's efforts resulted in the establishment of branch associations in a variety of rural and urban locations. In spite of local opposition and tremendous geographical, linguistic, social and political barriers, Bull applied himself to the task of providing a firm foundation for Black and Mixed Race SCA and YMCA members to find places in previously lily-white bodies.

Understanding both his limits as well as his capabilities, Bull's generosity allowed him to share the spotlight with other evangelists. His correspondence with YMCA leader John Mott demonstrates a humble willingness to see the task of ‘nonwhite’ inclusion in SCA and YMCA work to the end. By the time Max Yergan, the first permanent YMCA and SCA secretary arrived in South Africa early in 1922, Bull was able to delegate most of the duties that required a field secretary to him, satisfied that he could concentrate on the remainder of his managerial duties from the YMCA and SCA center, in Cape Town and Stellenbosch, respectively. Already fluent in Afrikaans, Bull's history of attempting to build bridges between competing and often hostile populations set the standard for the type of leadership that a complex, extremely ethnically and religiously particularistic society like South Africa would need to construct a broadly based national movement.

Although O.B. Bull is known only to readers of Alan Paton'sHofmeyr, and those involved in the institutions with which he was associated, most notably, St Edmunds School, Jesus College, Cambridge, the Scriptural Union and the South African SCA and YMCA, it may now be possible for later generations to revisit the times in which he lived and worked to regain a sense of the odds against which he struggled and the resolve he showed in striving first to dream of and then fight for a more inclusive Southern African YMCA.

While he was by no means perfect and was clearly himself a product of his place and time, his quests for something better within himself and his adopted country were noble.
Impact of solar‐induced stratospheric ozone decline on Southern Hemisphere westerlies during the Late Maunder Minimum
Authors: Varma V. , Prange M. , Spangehl T. , Lamy F. , Cubasch U. , Schulz M.
Published: September 2012

The Southern Hemisphere Westerly Winds (SWW) constitute an important zonal circulation system that dominates the dynamics of the Southern Hemisphere mid‐latitudes. In the present study, we analyze results from two transient simulations (1630–2000 AD) conducted with the coupled atmosphere‐ocean model EGMAM (ECHO‐G with Middle Atmosphere Model): one simulation with fixed stratospheric ozone concentration, and one with solar‐induced variations in stratospheric ozone content. The results suggest that during periods of lower solar activity, the annual‐mean SWW tend to get weaker on their poleward side and shift towards the equator. The SWW shift is more intense and robust for the simulation with varying stratospheric ozone, suggesting an important influence of solar‐induced stratospheric ozone variations on mid‐latitude troposphere dynamics. Finally, we present proxy evidence from a high‐resolution marine sediment core from the Chilean continental slope (41°S), which strongly supports the model result of an equatorward displacement of the SWW during the Maunder Minimum.
Variational fractional-spin density-functional theory for diradicals
Authors: Peng Degao , Hu Xiangqian , Devarajan Deepa , Ess Daniel H. , Johnson Erin R. , Yang Weitao
Published: September 2012

Accurate computation of singlet-triplet energy gaps of diradicals remains a challenging problem in density-functional theory (DFT). In this work, we propose a variational extension of our previous work [D. H. Ess, E. R. Johnson, X. Q. Hu, and W. T. Yang, J. Phys. Chem. A 115, 76 (2011)10.1021/jp109280y], which applied fractional-spin density-functional theory (FS-DFT) to diradicals. The original FS-DFT approach assumed equal spin-orbital occupancies of 0.5 α-spin and 0.5 β-spin for the two degenerate, or nearly degenerate, frontier orbitals. In contrast, the variational approach (VFS-DFT) optimizes the total energy of a singlet diradical with respect to the frontier-orbital occupation numbers, based on a full configuration-interaction picture. It is found that the optimal occupation numbers are exactly 0.5 α-spin and 0.5 β-spin for diradicals such as O2, where the frontier orbitals belong to the same multidimensional irreducible representation, and VFS-DFT reduces to FS-DFT for these cases. However, for diradicals where the frontier orbitals do not belong to the same irreducible representation, the optimal occupation numbers can vary between 0 and 1. Furthermore, analysis of CH2 by VFS-DFT and FS-DFT captures the 1A1 and 1B1 states, respectively. Finally, because of the static correlation error in commonly used density functional approximations, both VFS-DFT and FS-DFT calculations significantly overestimate the singlet-triplet energy gaps for disjoint diradicals, such as cyclobutadiene, in which the frontier orbitals are confined to separate atomic centers.
Instrument for layer-by-layer deposition of catalyst layers directly on proton exchange membrane for direct methanol fuel cell
Authors: Wang D. , Wang L. , Liang J. , Liu C.
Published: September 2012

A catalyst layer (CL) layer-by-layer (LbL) deposition instrument, consisting of an electrohydrodynamic atomization (EHDA) device and a proton exchange membrane (PEM) fixing device, has been developed. It has been used to deposit anode CL on Nafion membrane under different working distances of 4, 5, and 6 mm. The incorporation of EHDA LbL deposition allowed the generation of the CLs with different structures, where the higher working distance produced more porous CL structure. A catalyst-coated membrane (CCM) was also produced using this EHDA LbL deposition and PEM fixing device. It was observed that the catalyst has been uniformly coated on the Nafion membrane and the CCM presents an uniform surface feature. The performance of a single direct methanol fuel cell (DMFC) assembled with the deposited CCM at different working temperatures was analysed. The cell performance increased when the temperature rose. This instrument has the potential of being developed into a powerful device for controlling the deposition of CL of desired structures directly on PEM for DMFCs.
Micro glass ball embedded gels to study cell mechanobiological responses to substrate curvatures
Authors: Lee Sang Joo , Yang Shengyuan
Published: September 2012

The effects of substrate stiffness on cell behaviors have been extensively studied; however, the effects of substrate curvature are not well documented. The curvature of the surface to which cells adhere can have profound effects on cell behaviors. To reveal these cell mechanobiological responses to substrate curvatures, here we introduce a novel, unique, simple, and flexible class of substrates, polyacrylamide gels embedded with micro glass balls ranging in diameter from 5 μm to 2 mm, to culture cells. NIH-3T3 fibroblasts were cultured on these glass ball embedded gels. Morphologies of cells growing on glass balls were analyzed by using an optical microscope and a 3D confocal laser scanning microscope. The cell behaviors on micro cylindrical glass tubes having similar diameters to the glass balls were also compared. It is observed that the fibroblasts were sensitive to the curvatures of the glass balls. Significant differences in cell attachment rate, migration speed, and morphology were noted for cells cultured on glass balls of diameters at or below 500 μm, compared to those on glass balls of larger diameters. Cell spread area increased as a function of the ball diameter with three different slopes in the three distinct regions depending on the ball diameter. To the best of our knowledge, this is the first experimental attempt to study cell responses to spherically shaped substrates. These cell culture experiments imply that this class of substrates, micro glass ball embedded gels, can be useful tools to study cell mechanobiological responses to substrate curvatures, related cell and tissue engineering researches, and biomedical applications.
Nonlinear electron-magnetohydrodynamic simulations of three dimensional current shear instability
Authors: Jain Neeraj , Das Amita , Sengupta Sudip , Kaw Predhiman
Published: September 2012

This paper deals with detailed nonlinear electron-magnetohydrodynamic simulations of a three dimensional current shear driven instability in slab geometry. The simulations show the development of the instability in the current shear layer in the linear regime leading to the generation of electromagnetic turbulence in the nonlinear regime. The electromagnetic turbulence is first generated in the unstable shear layer and then spreads into the stable regions. The turbulence spectrum shows a new kind of anisotropy in which power transfer towards shorter scales occurs preferentially in the direction perpendicular to the electron flow. Results of the present three dimensional simulations of the current shear instability are compared with those of our earlier two dimensional simulations of sausage instability. It is found that the flattening of the mean velocity profile and thus reduction in the electron current due to generation of electromagnetic turbulence in the three dimensional case is more effective as compared to that in the two dimensional case.
Stability enhancement of an atomic force microscope for long-term force measurement including cantilever modification for whole cell deformation
Authors: Weafer P. P. , McGarry J. P. , van Es M. H. , Kilpatrick J. I. , Ronan W. , Nolan D. R. , Jarvis S. P.
Published: September 2012

Atomic force microscopy (AFM) is widely used in the study of both morphology and mechanical properties of living cells under physiologically relevant conditions. However, quantitative experiments on timescales of minutes to hours are generally limited by thermal drift in the instrument, particularly in the vertical (z) direction. In addition, we demonstrate the necessity to remove all air-liquid interfaces within the system for measurements in liquid environments, which may otherwise result in perturbations in the measured deflection. These effects severely limit the use of AFM as a practical tool for the study of long-term cell behavior, where precise knowledge of the tip-sample distance is a crucial requirement. Here we present a readily implementable, cost effective method of minimizing z-drift and liquid instabilities by utilizing active temperature control combined with a customized fluid cell system. Long-term whole cell mechanical measurements were performed using this stabilized AFM by attaching a large sphere to a cantilever in order to approximate a parallel plate system. An extensive examination of the effects of sphere attachment on AFM data is presented. Profiling of cantilever bending during substrate indentation revealed that the optical lever assumption of free ended cantilevering is inappropriate when sphere constraining occurs, which applies an additional torque to the cantilevers “free” end. Here we present the steps required to accurately determine force-indentation measurements for such a scenario. Combining these readily implementable modifications, we demonstrate the ability to investigate long-term whole cell mechanics by performing strain controlled cyclic deformation of single osteoblasts.
Crystal field disorder effects in the optical spectra of Nd3+ and Yb3+-doped calcium lithium niobium gallium garnets laser crystals and ceramics
Authors: Lupei V. , Lupei A. , Gheorghe C. , Gheorghe L. , Achim A. , Ikesue A.
Published: September 2012

The optical spectroscopic properties of RE3+ (Nd, 1 at. % or Yb, 1 to 10 at. %)-doped calcium-lithium-niobium-gallium garnet (CLNGG) single crystals and ceramics in the 10 K–300 K range are analyzed. In these compositionally disordered materials, RE3+ substitute Ca2+ in dodecahedral sites and the charge compensation is accomplished by adjusting the proportion of Li+, Nb5+, and Ga3+ to the doping concentration. The crystals and ceramics show similar optical spectra, with broad and structured (especially at low temperatures) bands whose shape depends on temperature and doping concentration. At 10 K, the Nd3+ 4I9/2 → 4F3/2, 5/2 and Yb3+ 2F7/2 → 2F5/2 absorption bands, which show prospect for diode laser pumping, can be decomposed in several lines that can be attributed to centers with large differences in the crystal field. The positions of these components are the same, but the relative intensity depends on the doping concentration and two main centers dominate the spectra. Non-selective excitation evidences broad emission bands, of prospect for short-pulse laser emission, whereas the selective excitation reveals the particular emission spectra of the various centers. The modeling reveals that the nonequivalent centers correspond to RE3+ ions with different cationic combinations in the nearest octahedral and tetrahedral coordination spheres, and the most abundant two centers have 4Nb and, respectively, 3Nb1Li in the nearest octahedral sphere. At 300 K, the spectral resolution is lost. It is then inferred that the observed optical bands are envelopes of the spectra of various structural centers, whose resolution is determined by the relative contribution of the temperature-dependent homogeneous broadening and the effects of crystal field disordering (multicenter structure, inhomogeneous broadening). The relevance of spectroscopic properties for selection of pumping conditions and of laser design that would enable utilization of the broad optical bands for efficient laser emission and reduced heat generation is discussed.
Phase transition of FePt/Ag nanocomposite thin films: Kinetics, activation volume, and atomic processes
Authors: Zhang Yongmei , Li Xiaohong , Jing Jingjing , Song Wenpeng , Li Yang , Liu Baoting , Zhang Xiangyi
Published: September 2012

Understanding the L10 phase transformation of FePt nanocrystals in FePt:X (X = nonmagnetic materials) nanocomposite thin films is of particular importance for controlling and designing these films as ultrahigh density magnetic recording media. In this study, by employing temperature- and pressure-dependence of the rate constant of phase transition, the nucleation (En = 0.3 eV) and growth (Eg = 0.9 eV) activation energies of L10 ordered domains, as well as an activation volume ΔV* ≈ 0.96 Ω (Ω = average atomic volume) for L10 ordering transition in FePt:Ag nanocomposite thin films have been successfully determined. These data suggest that the growth of L10 ordered domains is predominantly dependent on the diffusion of Fe atoms in FePt crystals, and that the diffusion of Ag atoms out of FePt lattice prompts the nucleation of the L10 ordered domains. These findings have a direct implication for designing FePt:Ag nanocomposite thin films with high pack fraction of L10-FePt nanocrystals.
Magnetic coupling constants and vibrational frequencies by extended broken symmetry approach with hybrid functionals
Authors: Bovi D. , Guidoni L.
Published: September 2012

The description of the electronic structure and magnetic properties of multi-centers transition metal complexes, especially of mixed-valence compounds, still represents a challenge for density functional theory (DFT) methods. The energies and the geometries of the correctly symmetrized low-spin ground state are estimated using the Heisenberg-Dirac-van Vleck spin Hamiltonian within the extended broken symmetry method introduced by Marx and co-workers [Nair et al., J. Chem. Theory Comput. 4, 1174–1188 (2008)10.1021/ct800089x]. In the present work we extend the application of this technique, originally implemented using the DFT+U scheme, to the use of hybrid functionals, investigating the ground-state properties of di-iron and di-manganese compounds. The calculated magnetic coupling and vibrational properties of ferredoxin molecular models are in good agreements with experimental results and DFT+U calculations. Six different mixed-valence Mn(III)–Mn(IV) compounds have been extensively studied optimizing the geometry in low-spin, high-spin, and broken-symmetry states and with different functionals. The magnetic coupling constants calculated by the extended broken symmetry approach using B3LYP functional presents a remarkable agreement with the experimental results, revealing that the proposed methodology provides a consistent and accurate DFT approach to the electronic structure of multi-centers transition metal complexes.
Absolute cross sections for vibrational excitations of cytosine by low energy electron impact
Authors: Michaud M. , Bazin M. , Sanche L.
Published: September 2012

The absolute cross sections (CSs) for vibrational excitations of cytosine by electron impact between 0.5 and 18 eV were measured by electron-energy loss (EEL) spectroscopy of the molecule deposited at monolayer coverage on an inert Ar substrate. The vibrational energies compare to those that have been reported from IR spectroscopy of cytosine isolated in Ar matrix, IR and Raman spectra of polycrystalline cytosine, and ab initio calculation. The CSs for the various H bending modes at 142 and 160 meV are both rising from their energy threshold up to 1.7 and 2.1 × 10−17 cm2 at about 4 eV, respectively, and then decrease moderately while maintaining some intensity at 18 eV. The latter trend is displayed as well for the CS assigned to the NH2 scissor along with bending of all H at 179 meV. This overall behavior in electron-molecule collision is attributed to direct processes such as the dipole, quadrupole, and polarization contributions, etc. of the interaction of the incident electron with a molecule. The CSs for the ring deformation at 61 meV, the ring deformation with N-H symmetric wag at 77 meV, and the ring deformations with symmetric bending of all H at 119 meV exhibit common enhancement maxima at 1.5, 3.5, and 5.5 eV followed by a broad hump at about 12 eV, which are superimposed on the contribution due to the direct processes. At 3.5 eV, the CS values for the 61-, 77-, and 119-meV modes reach 4.0, 3.0, and 4.5 × 10−17 cm2, respectively. The CS for the C-C and C-O stretches at 202 meV, which dominates in the intermediate EEL region, rises sharply until 1.5 eV, reaches its maximum of 5.7 × 10−17 cm2 at 3.5 eV and then decreases toward 18 eV. The present vibrational enhancements, correspond to the features found around 1.5 and 4.5 eV in electron transmission spectroscopy (ETS) and those lying within 1.5–2.1 eV, 5.2–6.8 eV, and 9.5–10.9 eV range in dissociative electron attachment (DEA) experiments with cytosine in gas phase. While the ETS features are ascribed to shape resonances associated with the electron occupation of the second and third antibonding π-orbitals of the molecule in its ground state, the correspondence with DEA features suggests the existence of common precursor anion states decaying with certain probabilities into the vibrationally excited ground state.
Measurement of net dopant concentration via dynamic photoluminescence
Authors: Giesecke J. A. , Schubert M. C. , Warta W.
Published: September 2012

This paper presents a class of methods to determine net dopant concentration of silicon wafers by means of dynamic or quasi-steady-state photoluminescence. In contrast to resistivity measurements, this approach is independent of assumptions about dopant type and majority carrier mobility. The latter fact makes it particularly interesting for the determination of net dopant concentration in compensated silicon, where conventional mobility models involving only one dopant species have been reported to fail. Our approach also allows access to majority carrier mobility via combination of net dopant concentration as inferred from photoluminescence with a resistivity measurement.