bluuebunny/crossref_metadata_2025 huggingface dataset:
Low plasma levels of antithrombin III in the early post‐operative period following pediatric liver transplantation: Should they be replaced? A single‐center pilot study
Authors: Quintero Jesús , Ortega Juan , Miserachs Mar , Bueno Javier , Bilbao Itxarone , Charco Ramón
Published: January 2014

eHAT after LT remains a life‐threatening complication. In the majority of anticoagulation protocols, heparin is used to prevent thromboses. Our study aimed to monitor AT‐III levels in the early post‐LT period to assess the need for the administration of AT‐III concentrate to ensure the effectiveness of heparin. We monitored coagulation daily by measuring INR, APTT, fibrinogen, platelets, and AT‐III. Anticoagulation therapy consisted of LMWH, AT‐III, and dipyridamole. AT‐III concentrate was administered when AT‐III activity was ≤60%. DUS was performed daily for the first five post‐operative days or whenever vascular thrombosis was suspected. Between October 2007 and October 2011, 39 LT were performed in our center. The median age was 26 months (6–196) with a median weight of 9 kg (5.5–49). AT‐III activity was ≤60% in 27 patients. Lower levels were particularly observed in partial grafts and recipients weighing less than 10 kg. Patent arterial flow was present in all 39 LT during the first five post‐operative days. AT‐III levels were low in 70% of pediatric patients following LT, thereby risking heparin ineffectiveness. These results may implicate low AT‐III levels in the etiology of eHAT post‐LT. However, this is a small single‐center pilot study and further larger prospective trials are required to confirm these results.
Growth following solid organ transplantation in childhood
Authors: Laster M. L. , Fine R. N.
Published: January 2014

One of the ultimate goals of successful transplantation in pediatric solid organ transplant recipients is the attainment of optimal final adult height. This manuscript will discuss the attainment of height following solid organ transplantation in pediatric recipients of kidney, liver, heart, lung, and small bowel transplantation. Age is a primary factor with younger recipients exhibiting the greatest immediate catch up growth. Graft function is a significant contributory factor with a reduction in glomerular filtration rate correlating with poor growth in kidney recipients and the need for re‐transplantation with impaired growth in liver recipients. The known adverse impact of steroids on growth has led to modification of steroid dosage and even to steroid withdrawal and steroid avoidance. In kidney and liver recipients, this has been associated with the development on occasion of acute rejection episodes. In infant heart transplantation, avoidance of maintenance corticosteroid immunosuppression is associated with normal growth velocity in the majority of patients. With marked improvement in patient and graft survival rates in pediatric organ graft recipients, it is timely that the quality of life issues, such as normal adult height, receive paramount attention. In general, normal growth post‐transplantation should be an achievable goal that results in normal adult height for many solid organ transplantation recipients.
Liver transplantation in an adolescent with acute liver failure from acute lymphoblastic leukemia
Authors: Reddi D. M. , Barbas A. S. , Castleberry A. W. , Rege A. S. , Vikraman D. S. , Brennan T. V. , Ravindra K. V. , Collins B. H. , Sudan D. L. , Lagoo A. S. , Martin A. E.
Published: January 2014

The most common identifiable causes of acute liver failure in pediatric patients are infection, drug toxicity, metabolic disease, and autoimmune processes. In many cases, the etiology of acute liver failure cannot be determined. Acute leukemia is an extremely rare cause of acute liver failure, and liver transplantation has traditionally been contraindicated in this setting. We report a case of acute liver failure in a previously healthy 15‐yr‐old male from pre‐B‐cell acute lymphoblastic leukemia. He underwent liver transplantation before the diagnosis was established, and has subsequently received chemotherapy for pre‐B‐cell acute lymphoblastic leukemia. He is currently alive 31 months post‐transplantation. The published literature describing acute lymphoblastic leukemia as a cause of acute liver failure is reviewed.
Reduced ATG‐F dosage for induction in pediatric renal transplantation: A single‐center experience
Authors: Shang Wenjun , Feng Guiwen , Gao Shilin , Wang Zhigang , Pang Xinlu , Li Jinfeng , Liu Lei , Feng Yonghua , Xie Hongchang , Zhang Shuijun , Qiao Baoping
Published: January 2014

Rabbit antithymocyte globulin (ATG‐F) is an extensively used induction agent. To our knowledge, no study to date has assessed reduced ATG‐F dosage in children undergoing renal transplantation. This was a retrospective analysis of pediatric renal recipients in the Department of Kidney Transplantation, The First Affiliated Hospital of Zhengzhou University, from May 2007 to February 2013. Thirty‐nine children underwent renal transplantation including 25 living related and 14 cardiac deceased donor transplantation. Each recipient received ATG‐F 1.5 mg/kg/d once daily for 4 days. Of the 39 recipients, five (12.8%) showed delayed graft function, including one of 25 recipients (4%) of living donor and four of 14 recipients (28.6%) of deceased donor transplantation (p < 0.05). Six of the 39 recipients (15.4%) showed acute rejection on renal biopsy. Follow‐up in these children ranged from 6 to 87 months. The one‐, three‐, and five‐yr recipients and grafts survival rates postoperation were each 94.9% and 97.3%, 97.3%, and 94.6%, respectively. The incidence of postoperative infection was 35.9% (14/39), and did not differ significantly in the living related and deceased donor groups (p > 0.05). Low‐dose ATG‐F can be safely used as an immune induction agent in pediatric renal transplantation.
Transient renal enlargement in pediatric hematopoietic cell transplant recipients
Authors: Chapman Teresa , Bodmer Nicholas , Benkeser David C. , Hingorani Sangeeta R. , Parisi Marguerite T.
Published: January 2014

Age‐dependent renal length tables are routinely used when interpreting pediatric ultrasound. Standard renal length tables may not be accurate for HCT patients due to treatment effects on kidney size. The purpose of this study was to determine whether renal size changes from expected lengths based on age after HCT in the absence of other markers of renal disease. Four hundred and fifty renal measurements were made on 101 patients who underwent HCT between 2006 and 2010. Renal length was measured at 1–90 days pre‐HCT and at 0–30, 31–90, 91–180, and 181+ days post‐HCT. Values were compared with normal renal length tables. Average post‐HCT renal lengths were greater than established normative renal length data within every age group. Age‐adjusted average renal lengths measured at 0–30 and 31–90 days post‐transplantation were significantly larger than pre‐HCT renal lengths, with relative increases of 6.9% (4.5, 9.4; p < 0.001) and 3.9% (1.4, 6.4; p = 0.003), respectively. Average renal length did not differ significantly after 90 days post‐transplantation. HCT patients may have larger kidneys in the absence of renal disease. Awareness of the potential phenomenon of transient renal enlargement following HCT can prevent misdiagnosis and eliminate unnecessary diagnostic evaluations, interventions, anxiety, resource allocation, and financial costs.
Do Home Visiting Services Received During Pregnancy Improve Birth Outcomes? Findings from Virginia PRAMS 2007–2008
Authors: Shah Monisha K. , Austin Kristin R.
Published: January 2014

Objectives

Reducing poor birth outcomes are national and state priorities. At the national level participation in home visiting services has gained momentum with the recent appropriation of federal funds for states to implement evidence‐based maternal and child health home visiting programs. The effects of having a home visit are unknown at the state level.

Design and Sample

Using cross‐sectional data from 2007 to 2008 Virginia Pregnancy Risk Assessment and Monitoring System (PRAMS), maternal and infant outcomes were examined. Women who had a home visit during pregnancy were assigned into the home visiting (HV) participation group and those who did not were assigned to the HV Comparison group and used for the analysis.

Measures

Bivariate analyses, Rao‐Scott chi square tests, and multivariate logistic regression measured and quantified the association between HV participation and outcomes.

Results

The HV Participation group were 87.5% less likely to have a low birth weight infant (0.13, 95% CI: 0.020, 0.78), 4.5 times more likely to initiate breastfeeding (aOR: 4.5, 95% CI: 1.05, 19.54), and 39 times more likely to use contraceptives postpartum (aOR: 38.55, 95% CI: 3.14, 473.21).

Conclusions

Receiving home visiting services during pregnancy increased breastfeeding initiation and postpartum contraceptive use while reducing the risk of low birth weight.
Regulation of epinasty induced by 2,4‐dichlorophenoxyacetic acid in pea and Arabidopsis plants
Authors: Pazmiño D. M. , Rodríguez‐Serrano M. , Sanz M. , Romero‐Puertas M. C. , Sandalio L. M.
Published: January 2014

The herbicide 2,4‐dichlorophenoxyacetic acid (2,4‐D) causes uncontrolled cell division and malformed growth in plants, giving rise to leaf epinasty and stem curvature. In this study, mechanisms involved in the regulation of leaf epinasty induced by 2,4‐D were studied using different chemicals involved in reactive oxygen species (ROS) accumulation (diphenyleniodonium, butylated hydroxyanisole, EDTA, allopurinol), calcium channels (LaCl3), protein phosphorylation (cantharidin, wortmannin) and ethylene emission/perception (aminoethoxyvinyl glycine, AgNO3). The effect of these compounds on the epinasty induced by 2,4‐D was analysed in shoots and leaf strips from pea plants. For further insight into the effect of 2,4‐D, studies were also made in Arabidopsis mutants deficient in ROS production (rbohD, rbohF, xdh), ethylene (ein 3‐1, ctr 1‐1, etr 1‐1), abscisic acid (aba 3.1), and jasmonic acid (coi 1.1, jar 1.1, opr 3) pathways. The results suggest that ROS production, mainly ·OH, is essential in the development of epinasty triggered by 2,4‐D. Epinasty was also found to be regulated by Ca2+, protein phosphorylation and ethylene, although all these factors act downstream of ROS production. The use of Arabidopsis mutants appears to indicate that abscisic and jasmonic acid are not involved in regulating epinasty, although they could be involved in other symptoms induced by 2,4‐D.
Inventory Rationing in a Make‐to‐Stock System with Batch Production and Lost Sales
Authors: Pang Zhan , Shen Houcai , Cheng T. C. E.
Published: January 2014

We address an inventory rationing problem in a lost sales make‐to‐stock (MTS) production system with batch ordering and multiple demand classes. Each production order contains a single batch of a fixed lot size and the processing time of each batch is random. Assuming that there is at most one order outstanding at any point in time, we first address the case with the general production time distribution. We show that the optimal order policy is characterized by a reorder point and the optimal rationing policy is characterized by time‐dependent rationing levels. We then approximate the production time distribution with a phase‐type distribution and show that the optimal policy can be characterized by a reorder point and state‐dependent rationing levels. Using the Erlang production time distribution, we generalize the model to a tandem MTS system in which there may be multiple outstanding orders. We introduce a state‐transformation approach to perform the structural analysis and show that both the reorder point and rationing levels are state dependent. We show the monotonicity of the optimal reorder point and rationing levels for the outstanding orders, and generate new theoretical and managerial insights from the research findings.
Assortment Optimization under the Multinomial Logit Model with Random Choice Parameters
Authors: Rusmevichientong Paat , Shmoys David , Tong Chaoxu , Topaloglu Huseyin
Published: January 2014

We consider assortment optimization problems under the multinomial logit model, where the parameters of the choice model are random. The randomness in the choice model parameters is motivated by the fact that there are multiple customer segments, each with different preferences for the products, and the segment of each customer is unknown to the firm when the customer makes a purchase. This choice model is also called the mixture‐of‐logits model. The goal of the firm is to choose an assortment of products to offer that maximizes the expected revenue per customer, across all customer segments. We establish that the problem is NP complete even when there are just two customer segments. Motivated by this complexity result, we focus on assortments consisting of products with the highest revenues, which we refer to as revenue‐ordered assortments. We identify specially structured cases of the problem where revenue‐ordered assortments are optimal. When the randomness in the choice model parameters does not follow a special structure, we derive tight approximation guarantees for revenue‐ordered assortments. We extend our model to the multi‐period capacity allocation problem, and prove that, when restricted to the revenue‐ordered assortments, the mixture‐of‐logits model possesses the nesting‐by‐fare‐order property. This result implies that revenue‐ordered assortments can be incorporated into existing revenue management systems through nested protection levels. Numerical experiments show that revenue‐ordered assortments perform remarkably well, generally yielding profits that are within a fraction of a percent of the optimal.
Inventory Sharing with Transshipment: Impacts of Demand Distribution Shapes and Setup Costs
Authors: Liang Chao , Sethi Suresh P. , Shi Ruixia , Zhang Jun
Published: January 2014

We study a firm's optimal transshipment problem considering the impacts of setup costs for transshipment and demand distribution shapes. We assume that the demand follows a three‐point distribution, which changes from a degenerate distribution, to a unimodal distribution, and to a bimodal distribution as the demand shape parameter increases. We find that as the demand shape parameter increases, the optimal transshipment strategy changes from no transshipment to transshipment, and finally to no transshipment. The firm would use two‐way transshipment when the shape parameter is relatively small, while it would use one‐way transshipment when the shape parameter is relatively large. When the optimal strategy is one‐way transshipment, the transshipment direction depends on the contribution margin as well as the demand shape, when the difference between the two demand uncertainties is small. Our study of a dual‐channel retail system shows that the additional benefit of two‐way transshipment is negligible when there are many retail stores.
Benchmark Dose Calculation for Ordered Categorical Responses
Authors: Chen Chu‐Chih , Chen James J.
Published: January 2014

The use of benchmark dose (BMD) calculations for dichotomous or continuous responses is well established in the risk assessment of cancer and noncancer endpoints. In some cases, responses to exposure are categorized in terms of ordinal severity effects such as none, mild, adverse, and severe. Such responses can be assessed using categorical regression (CATREG) analysis. However, while CATREG has been employed to compare the benchmark approach and the no‐adverse‐effect‐level (NOAEL) approach in determining a reference dose, the utility of CATREG for risk assessment remains unclear. This study proposes a CATREG model to extend the BMD approach to ordered categorical responses by modeling severity levels as censored interval limits of a standard normal distribution. The BMD is calculated as a weighted average of the BMDs obtained at dichotomous cutoffs for each adverse severity level above the critical effect, with the weights being proportional to the reciprocal of the expected loss at the cutoff under the normal probability model. This approach provides a link between the current BMD procedures for dichotomous and continuous data. We estimate the CATREG parameters using a Markov chain Monte Carlo simulation procedure. The proposed method is demonstrated using examples of aldicarb and urethane, each with several categories of severity levels. Simulation studies comparing the BMD and BMDL (lower confidence bound on the BMD) using the proposed method to the correspondent estimates using the existing methods for dichotomous and continuous data are quite compatible; the difference is mainly dependent on the choice of cutoffs for the severity levels.
Aggregate Human Health Risk Assessment from Dust of Daily Life in the Urban Environment of Beijing
Authors: Xu L.Y. , Shu X.
Published: January 2014

Because of the high emissions of polycyclic aromatic hydrocarbons (PAHs) into the environment by the increasing number of vehicles in Beijing and the absorption of these PAHs onto particulates, the performance of a preliminary health risk assessment of the aggregate exposure to PAHs of urban citizens in daily life is very important. Urban dust can be used to examine the aggregation of atmospheric particulates from local pollution sources over a long time period and the direct exposure of the urban human population. The environment's correlative with clothing, dining, residing, and traveling in urban daily life was assessed using exposure‐receptor‐oriented analysis. The multipathway exposure model was used to simulate the lifetime exposure of a female citizen to PAHs in dust. All of the PAH concentrations in dust for each behavior and its correlative environment in Beijing were acceptable because all of the carcinogenic risks of PAHs in the dust were approximately 1.0 × 10–6. The dominant induced carcinogenic risks in the dust were Benzo(a)pyrene and Dibenzo(a,h)anthracene. The main carcinogenic risk routes for humans were dermal contact and oral intake, which contributed on average 99.78% of the risk. Indoor risk is especially important, as the decoration and height within the building were important impact factors for carcinogenic risk induced by indoor PAHs. For people living in an urban area, a healthy lifestyle includes less decoration per room, living on a low floor, wearing a respirator, and reducing exposed skin area when traveling.
Aeolian sediment transport and deposition in a modern high‐latitude glacial marine environment
Authors: Chewings Jane M. , Atkins Cliff B. , Dunbar Gavin B. , Golledge Nicholas R.
Published: January 2014

Aeolian sand and dust in polar regions are transported offshore over sea ice and released to the ocean during summer melt. This process has long been considered an important contributor to polar sea floor sedimentation and as a source of bioavailable iron that triggers vast phytoplankton blooms. Reported here are aeolian sediment dispersal patterns and accumulation rates varying between 0·2 g m−2 yr−1 and 55 g m−2 yr−1 over 3000 km2 of sea ice in McMurdo Sound, south‐west Ross Sea, adjacent to the largest ice free area in Antarctica. Sediment distribution and the abundance of southern McMurdo Volcanic Group‐derived glass, show that most sediment originates from the McMurdo Ice Shelf and nearby coastal outcrops. Almost no sediment is derived from the extensive ice free areas of the McMurdo Dry Valleys due to winnowed surficial layers shielding sand‐sized and silt‐sized material from wind erosion and because of the imposing topographic barrier of the north‐south aligned piedmont glaciers. Southerly winds of intermediate strength (ca 20 m sec−1) are primarily responsible for transporting sediment northwards and offshore. The results presented here indicate that sand‐sized sediment does not travel more than ca 5 km offshore, but very‐fine sand and silt grains can travel >100 km from source. For sites >10 km from the coast, the mass accumulation rate is relatively uniform (1·14 ± 0·57 g m−2 yr−1), three orders of magnitude above estimated global atmospheric dust values for the region. This uniformity represents a sea floor sedimentation rate of only 0·2 cm kyr−1, well below the rates of >9 cm kyr−1 reported for biogenic‐dominated sedimentation measured over much of the Ross Sea. These results show that, even for this region of high‐windblown sediment flux, aeolian processes are only a minor contributor to sea floor sedimentation, excepting areas proximal to coastal sources.
Role of vegetation in shaping Early Pennsylvanian braided rivers: Architecture of the Boss Point Formation, Atlantic Canada
Authors: Ielpi Alessandro , Gibling Martin R. , Bashforth Arden R. , Lally Corinne , Rygel Michael C. , Al‐Silwadi Saif
Published: January 2014

Vegetation is a major driver of fluvial dynamics in modern rivers, but few facies models incorporate its influence. This article partially fills that gap by documenting the stratigraphy, architecture and palaeobotany of the Lower Pennsylvanian Boss Point Formation of Atlantic Canada, which contains some of the Earth's earliest accumulations of large woody debris. Braided‐fluvial systems occupied channel belts of varied scale within valleys several tens of metres deep and more than 12 km wide, and their deposits predominantly consist of sandy and gravelly bedforms with subordinate accretionary macroforms, high flow‐strength sand sheets and rippled abandonment facies. Discrete accumulations of clastic detritus and woody debris are up to 6 m thick and constitute at least 18% of the in‐channel deposits; they represent lags at the base of large and small channels, fills of minor channels and sandy macroforms that developed in central positions in the upper parts of channel fills. Sandstones with roots and other remnants of in situ vegetation demonstrate that vegetated islands were present, and the abundance of discrete channel fills suggests that the formation represents an anabranching, island‐braided sandbed river, the earliest example documented to date. Although some sphenopsid and lycopsid remains are present, most woody fragments are derived from cordaitalean trees, and the evolution of this group late in the Mississippian is inferred to have exerted a significant influence on fluvial morphodynamic patterns. The formation records a landscape in which active channel belts alternated with well‐drained floodplains colonized by dense, mature forests and local patches of pioneering, disturbance‐tolerant vegetation. Lakes and poorly drained floodplains dominated by carbonate and organic deposition, respectively, were also present. A large supply of woody debris triggered channel blockage and avulsion, and active channel margins and islands within the channel belts were initially colonized by pioneer vegetation and subsequently stabilized by large trees. A similar alternation of stable and unstable conditions is observed in modern braided rivers actively influenced by vegetation.
Connectedness and Suicide Prevention in Adolescents: Pathways and Implications
Authors: Whitlock Janis , Wyman Peter A. , Moore Sarah R.
Published: January 2014

Adolescent suicide is a major public health concern. Stressing the need for public health–based solutions, the Centers for Disease Control and Prevention identified “connectedness” as one means of pursuing this agenda. To advance this effort in suicide prevention with adolescents, (1) consistencies and variation in the literature overtly linking connectedness to suicide thoughts and behaviors (STB) are reviewed, (2) three more specific mechanistic pathways are proposed whereby connectedness may influence STB, and (3) several implications related to use of connectedness as a public health framework for adolescent suicide prevention and intervention are outlined.
Doing Family Without Having Kids
Authors: Blackstone Amy
Published: January 2014

Families that do not include children are largely overlooked by family scholars and in popular discourse. Yet this is one of several family forms that has grown in developed nations since the 1970s. As increasingly fewer adults choose to become parents, understanding the families they create, and the consequences of these family forms, will become even more important. Studies of childless adults reveal that they create bonds to fulfill many of the same functions that families with children fulfill. Research on how, and the extent to which, the childless “do” family without kids is reviewed and suggestions for future research are made.
Student Strategies Suggesting Emergence of Mental Structures Supporting Logical and Abstract Thinking: Multiplicative Reasoning
Authors: Carrier Jim
Published: January 2014

For many students, developing mathematical reasoning can prove to be challenging. Such difficulty may be explained by a deficit in the core understanding of many arithmetical concepts taught in early school years. Multiplicative reasoning is one such concept that produces an essential foundation upon which higher‐level mathematical thinking skills are built. The purpose of this study is to recognize indicators of multiplicative reasoning among fourth‐grade students. Through cross‐case analysis, the researcher used a test instrument to observe patterns of multiplicative reasoning at varying levels in a sample of 14 math students from a low socioeconomic school. Results indicate that the participants fell into three categories: premultiplicative, emergent, and multiplier. Consequently, 12 new sublevels were developed that further describe the multiplicative thinking of these fourth graders within the categories mentioned. Rather than being provided the standard mathematical algorithms, students should be encouraged to personally develop their own unique explanations, formulas, and understanding of general number system mechanics. When instructors are aware of their students' distinctive methods of determining multiplicative reasoning strategies and multiplying schemes, they are more apt to provide the most appropriate learning environment for their students.
Provision of private, piped water and sewerage connections and directly observed handwashing of mothers in a peri‐urban community of Lima, Peru
Authors: Oswald William E. , Hunter Gabrielle C. , Kramer Michael R. , Leontsini Elli , Cabrera Lilia , Lescano Andres G. , Gilman Robert H.
Published: January 2014

Objectives

To estimate the association between improved water and sanitation access and handwashing of mothers living in a peri‐urban community of Lima, Peru.

Methods

We observed 27 mothers directly, before and after installation of private, piped water and sewerage connections in the street just outside their housing plots, and measured changes in the proportion of faecal‐hand contamination and hand‐to‐mouth transmission events with handwashing.

Results

After provision of water and sewerage connections, mothers were approximately two times more likely to be observed washing their hands within a minute of defecation, compared with when they relied on shared, external water sources and non‐piped excreta disposal (RR = 2.14, 95% CI = 0.99–4.62). With piped water and sewerage available at housing plots, handwashing with or without soap occurred within a minute after 48% (10/21) of defecation events and within 15 min prior to 8% (11/136) of handling food events.

Conclusions

Handwashing increased following installation of private, piped water and sewerage connections, but its practice remained infrequent, particularly before food‐related events. Infrastructural interventions should be coupled with efforts to promote hygiene and ensure access to water and soap at multiple on‐plot locations convenient to mothers.
Quantifying filariasis and malaria control activities in relation to lymphatic filariasis elimination: a multiple intervention score map (MISM) for Malawi
Authors: Stanton Michelle C. , Mkwanda Square , Mzilahowa Themba , Bockarie Moses J. , Kelly‐Hope Louise A.
Published: January 2014

Objective

To quantify the geographical extent of filariasis and malaria control interventions impacting lymphatic filariasis (LF) in Malawi and to produce a multiple intervention score map (MISM) for prioritising surveillance and intervention strategies.

Methods

Interventions included mass drug administration (MDA) for LF and onchocerciasis, and bed nets and indoor residual spraying (IRS) for malaria. District and subdistrict‐level data were obtained from the Ministry of Health in Malawi, the Demographic and Health Survey (DHS) and President's Malaria Initiative reports. Single intervention scores were calculated for each variable based on population coverage thresholds, and these were combined in a weighted sum to form a multiple intervention score, which was then used to produce maps, that is MISMs. Districts were further classified into four groups based on the combination of their baseline LF prevalence and multiple intervention score.

Results

The district‐ and subdistrict‐level MISMs highlighted specific areas that have received high and low coverage of LF‐impacting interventions. High coverage areas included the LF‐onchocerciasis endemic areas in the southern region of the country and areas along the shores of Lake Malawi, where malaria vector control had been prioritised. Three districts with high baseline LF prevalence measures but low coverage of multiple interventions were identified and considered to be most at risk of ongoing transmission or re‐emergence.

Conclusions

These maps and district classifications will be used by LF programme managers to identify and target high‐risk areas that may not have received adequate LF‐impacting interventions to interrupt the transmission of the disease.
Nonmuscle Myosin II Is a Critical Regulator of Clathrin‐Mediated Endocytosis
Authors: Chandrasekar Indra , Goeckeler Zoe M. , Turney Stephen G. , Wang Peter , Wysolmerski Robert B. , Adelstein Robert S. , Bridgman Paul C.
Published: January 2014

Variable requirements for actin during clathrin‐mediated endocytosis (CME) may be related to regional or cellular differences in membrane tension. To compensate, local regulation of force generation may be needed to facilitate membrane curving and vesicle budding. Force generation is assumed to occur primarily through actin polymerization. Here we examine the role of myosin II using loss of function experiments. Our results indicate that myosin II acts on cortical actin scaffolds primarily in the plane of the plasma membrane (bottom arrow) to generate changes that are critical for enhancing CME progression.
Testing the performance of registered herbicides on the control of Campuloclinium macrocephalum (Asteraceae) in South African grasslands
Authors: Goodall J M , Witkowski E T F
Published: January 2014

We report on the performance of the registered herbicides picloram and metsulfuron‐methyl on the control of Campuloclinium macrocephalum (pompom weed) in grasslands. Herbicide trials in hydric and xeric grasslands were treated for three consecutive years in either summer (February) or autumn (April) and monitored for an additional 3 years after spraying ceased. Uncontrolled factors such as a host‐specific rust, fire and drought were observed from the second year of the study. Metsulfuron‐methyl and picloram did not differ in efficacy according to the timing of applications, but average mortality of marked plants was <80% expected of registered herbicides. Populations of C. macrocephalum in plots were reduced proportionately to the percentage mortality of marked plants. Picloram and metsulfuron‐methyl applied at 252 g a.i. ha−1 and 45 g a.i. ha−1, respectively, were not detectable by gas chromatography in the upper 25 cm of the soil profile during any of the sampling intervals from 0 to 56 days after treatment. Three annual applications of registered herbicide did not reduce C. macrocephalum successfully, and it is estimated that between five (summer) to seven (autumn) annual treatments are required to reduce weed density to <1 plant per plot (25 m2). Future research should focus on rust–herbicide interactions, the role of fire in seedbank management and fire as a treatment that could be integrated with chemical control.
Muscle contraction increases interstitial nitric oxide as predicted by a new model of local blood flow regulation
Authors: Golub Aleksander S. , Song Bjorn K. , Pittman Roland N.
Published: January 2014

Key points

The metabolic theory of blood flow regulation suggests that, when tissue cells experience a reduction of oxygen supply, they produce metabolic vasodilators, which increase the lumen of arterioles and hence local blood flow.

A century of intensive research has not found a single metabolic vasodilator to account for observed flow changes, therefore current thought is that there are many vasodilators.

We have proposed an alternative hypothesis based on the interaction of two well‐known molecular mechanisms for generation and removal of the intercellular signalling radicals nitric oxide (NO) and superoxide.

The proposed mechanism of regulation predicts a sharp increase in NO concentration in the intercellular space at the onset of muscle contraction.

Experiments with the NO‐sensitive fluorescent indicator DAF‐FM, loaded into the intercellular space, confirmed the rapid response of the NO‐related signal at the beginning of contractions and rapid washout of the indicator after their termination.

The prevailing metabolic theory of local blood flow regulation suggests the dilatation of arterioles in response to tissue hypoxia via the emission of multiple metabolic vasodilators by parenchymal cells. We have proposed a mechanism of regulation, built from well‐known components, which assumes that arterioles are normally dilated in metabolically active tissues, due to the emission of NO by the endothelium of microvessels. Regulation of local blood flow aims at preventing an excessive supply of oxygen (O2) and glucose to the tissue and thus provides an adequate supply, in contrast to the metabolic regulation theory which requires permanent hypoxia to generate the metabolic vasodilators. The mediator of the restrictive signal is superoxide anion (O2−) released by membrane NAD(P)H oxidases into the interstitial space, where it neutralizes NO at a diffusion‐limited rate. This model predicts that the onset of muscle contraction will lead to the cessation of O2− production, which will cause an elevation of interstitial NO concentration and an increase in fluorescence of the NO probe DAF‐FM after its conversion to DAF‐T. The time course of DAF‐T fluorescence in contracting muscle is predicted by also considering the washout from the muscle of the interstitially loaded NO indicator. Experiments using pulse fluorimetry confirmed an increase in the interstitial concentration of NO available for reaction with DAF‐FM during bouts of muscle contraction. The sharp increase in interstitial [NO] is consistent with the hypothesis that the termination of the neutralizing superoxide flow into the interstitium is associated with the activation of mitochondria and a reduction of the interstitial oxygen tension. The advantage of the new model is its ability to explain the interaction of metabolic activity and local blood flow through the adequate delivery of glucose and oxygen.
An Innovative Way to Solve Problems Associated With Circular Connector Electrical Bonding Resistance
Authors: Wang Frank Fan
Published: January 2014

Cadmium plated circular connectors and chromate conversion coated aluminum chassis are widely used on electronic equipment for both civilian and military aerospace applications. This article discusses electrical bonding resistance problems associated with cadmium plated circular connectors and chromate conversion coated aluminum chassis and proposes an innovative way to solve that problem.
Prediction of Hot Aisle Partition Airflow Boundary Conditions
Authors: Song Zhihang , Murray Bruce T. , Sammakia Bahgat
Published: January 2014

The integration of a simulation-based Artificial Neural Network (ANN) with a Genetic Algorithm (GA) has been explored as a real-time design tool for data center thermal management. The computation time for the ANN-GA approach is significantly smaller compared to a fully CFD-based optimization methodology for predicting data center operating conditions. However, difficulties remain when applying the ANN model for predicting operating conditions for configurations outside of the geometry used for the training set. One potential remedy is to partition the room layout into a finite number of characteristic zones, for which the ANN-GA model readily applies. Here, a multiple hot aisle/cold aisle data center configuration was analyzed using the commercial software FloTHERM. The CFD results are used to characterize the flow rates at the inter-zonal partitions. Based on specific reduced subsets of desired treatment quantities from the CFD results, such as CRAC and server rack air flow rates, the approach was applied for two different CRAC configurations and various levels of CRAC and server rack flow rates. Utilizing the compact inter-zonal boundary conditions, good agreement for the airflow and temperature distributions is achieved between predictions from the CFD computations for the entire room configuration and the reduced order zone-level model for different operating conditions and room layouts.
Numerical Calculation of the Pulse Compression of Ultrashort Pulse Laser Light by Means of the Thermoreflectance of SiC Substrate
Authors: Doan Hong Duc , Fushinobu Kazuyoshi
Published: January 2014

A numerical model of the thermoreflectance of doped SiC substrate and typical numerical results are presented. The model considers the temporal response of the electron temperature and the number density of the electronic carriers. Calculated results show steep increase of electron temperature and the resulting increase of reflectivity. As a result, the reflected laser pulse by the substrate is compressed in time domain by means of the temporal response of the thermoreflectance characteristics of SiC substrate. Thermal analysis of the electrons reveals the interesting feature of the thermoreflectance response as a function of pulse intensity, pulse width, or doping concentration. The technique can be used for the compression of ultrashort pulse laser light.
Thermo-Electric Modeling of Nanotube-Based Environmental Sensors
Authors: Martin Michael James , Manohara Harish
Published: January 2014

Free-standing electrically conductive nanotube and nano-bridge structures offer a simple, small-scale, low-power option for pressure and temperature sensing. To sense pressure, a constant voltage is applied across the bridge. At small scales, the heat transfer coefficient is pressure-dependent. The change in the heat transfer coefficients result in the circuit operating at higher temperatures, with different resistances, at low pressures. This in turn will lead to a change in the electrical resistivity of the system. If the system is held at constant voltage, this can be measured as a change in the current in such systems, representing a simple alternative to existing Pirani gauges. The current work simulates the Joule heating, conduction and convection heat transfer of a 5 micron long suspended single-wall carbon nanotube, incorporating temperature-sensitive material properties. The simulation allows prediction of the thermo-electrical response of the systems. The results agree with the trends observed in existing devices. Additional results look at the effects of system length, temperature, and contact resistances between the substrate and the device.
Study on the Flow and Heat Transfer Characteristics of Pulsating Heat Pipe With Asymmetric Configuration
Authors: Kwon Gi Hwan , Kim Sung Jin
Published: January 2014

The effects of asymmetric configuration on the flow and heat transfer characteristics of pulsating heat pipes (PHPs) were experimentally studied. Asymmetric configurations promote circulation motion of working fluid inside PHPs. Circulatory flow is desirable for thermal performance enhancement because the circulation of the working fluid increases the capability of the working fluid to transport heat from the evaporation zone to the condensation zone. Generally, as inclination angle decreases from a vertical position to horizontal position, thermal performance of the PHP decreases. However, it is expected that performance degradation according to inclination angle can be minimized when circulating motion exists in the PHP. Varying channel diameter was used to effectively generate circulating flow in the PHP. Experiments were performed to investigate the effect of variation in channel diameter on the flow and heat transfer characteristics of PHPs made of capillary glass tubes which have different inner diameters. Inner diameters of the tubes which were used were 1.2, 1.7, 2.2 mm, respectively. Three of the studied PHPs were composed of two parallel tubes of different diameter connected with each other, and remaining were composed of two tubes of the same diameter. Experimental results show that flow patterns changes according to input heat power. Low amplitude oscillation motion turned to larger amplitude oscillation and then circulation flow in one direction as increasing input power. Visualization results present that asymmetric PHPs with varying channel diameter show circulatory flow over a wider range of heat input compared to normal PHPs. In addition, experimental results indicate that variation in channel diameter helps to enhance the thermal performance of the PHP, especially as inclination angle decreases. This paper proves that channel configuration with variation in diameter can be one effective way of improving the performance of the PHP.
Diagnostic Technique for Quantitative Resolution of Three-Dimensional Liquid-Gas Phase Boundaries in Microchannel Flows
Authors: Patel Ravi S. , Garimella Suresh V.
Published: January 2014

The morphology of liquid-gas interfaces in adiabatic two-phase microchannel flow through a transparent acrylic microchannel of 500 μm × 500 μm square cross section is investigated. Water seeded with 0.5 μm-diameter fluorescent polystyrene particles is pumped through the channel, and the desired adiabatic two-phase flow regime is achieved through controlled air injection. The diagnostic technique relies on obtaining particle position data through epifluorescent imaging of the flow at excitation and emission wavelengths of 532 and 620 nm, respectively. The particle positions are then used to resolve interface locations to within ±2 μm in the viewing plane. This technique was previously demonstrated by the authors for a static meniscus in a capillary tube. The complete interface geometry between liquid and gas phases is obtained for operation in the annular flow regime by mapping the interface within individual focal planes at various depths within the channel. The diagnostic technique is shown to successfully locate and measure interfaces between transparent, immiscible fluids in a dynamic microchannel flow environment.
Laser Processing by Using Fluidic Laser Beam Shaper
Authors: Doan Hong Duc , Iwatani Naoki , Fushinobu Kazuyoshi
Published: January 2014

Laser beam shaping techniques are important to optimize a large number of laser-material processing applications and laser-material interaction studies. The authors have developed a novel fluidic laser beam shaper (FLBS) with merits such as flexiblility, versatility and low cost. This work presents a fundamentally new approach for laser beam shaping by using FLBS. A Gaussian beam profile is transformed to a flat top beam and annular beam profile in the focal plane. The shaped laser beam is used for laser drilling to investigate the influence of the laser intensity profile in laser processing. The paper concludes with suggestions for future research and potential applications for further the work.
Performance Analysis of a Combination System of Concentrating PV/T Collector and TEGs
Authors: Xu Xinqiang , Zhou Siyi , Meyers Mark , Sammakia Bahgat G. , Murray Bruce
Published: January 2014

Thermoelectric modules utilize available temperature differences to generate electricity by the Seebeck effect. The current study investigates the merits of employing thermoelectrics to harvest additional electric energy instead of just cooling concentrating photovoltaic (CPV) modules by heat sinks (heat extractors). One of the attractive options to convert solar energy into electricity efficiently is to laminate TE modules between CPV modules and heat extractors to form a CPV-TE/thermal hybrid system. In order to perform an accurate estimation of the additional electrical energy harvested, a coupled field model is developed to calculate the electrical performance of TE devices, which incorporates a rigorous interfacial energy balance including the Seebeck effect, the Peltier effect, and Joule heating, and results in better predictions of the conversion capability. Moreover, a 3D multiphysics computational model for the hybrid concentrating PV-TE/thermal (CPV-TE/T) water collector system consisting of a solar concentrator, 10 serially-connected GaAs/Ge PV cells, 300 couples of bismuth telluride TE modules, and a cooling channel with heat-recovery capability, is implemented by using the commercial FE–tool COMSOL™. A conjugate heat transfer model is used, assuming laminar flow through the cooling channel. The performance and efficiencies of the hybrid system are analyzed. As compared with the traditional PV/T system, a comparable thermal efficiency and a higher 8% increase of the electrical efficiency can be observed through the PV-TE hybrid system. Additionally, with the identical convective surface area and cooling flow rate in both configurations, the PV-TE/T hybrid system yields higher PV cell temperatures but more uniform temperature distributions across the cell array, which thus eliminates the current matching problem; however, the higher cell temperatures lower the PV module’s fatigue life, which has become one of the biggest challenges in the PV-TE hybrid system.
Unified Creep Plasticity Damage (UCPD) Model for SAC396 Solder
Authors: Neilsen Michael , Vianco Paul
Published: January 2014

A unified creep plasticity damage (UCPD) model for Sn-Pb and Pb-free solders was developed and implemented into finite element analysis codes. The new model will be described along with the relationship between the model’s damage evolution equation and an empirical Coffin-Manson relationship for solder fatigue. Next, developments needed to model crack initiation and growth in solder joints will be described. Finally, experimentally observed cracks in typical solder joints subjected to thermal mechanical fatigue are compared with model predictions. Finite element based modeling is particularly suited for predicting solder joint fatigue of advanced electronics packaging, e.g. package-on-package (PoP), because it allows for evaluation of a variety of package materials and geometries.
Efficient Implementation of Potential-Flow Airflow Prediction for Data Centers
Authors: Healey Christopher M. , VanGilder James W. , Zhang Xuanhang (Simon)
Published: January 2014

We present improvements to airflow prediction techniques for data centers, specifically within potential flow models. As a potential-flow model presents a simplified solution to the room airflow physics, additional approximations can be implemented to improve runtime without changing the accuracy of potential-flow. The improvements concentrate on two main components of current prediction methods: namely, the pre-processing task of automatic and efficient grid generation and post-processing task of capture index (CI) calculation. We propose a variable grid oriented around the objects in the room, creating cells with variable sizes (in width, height, and depth). We also show how CI calculations can be made more efficient through an understanding of the local nature of CI. An empirical study of sample data center layouts shows that these improvements can yield significant improvements in speed while maintaining a good level of accuracy.