bluuebunny/crossref_metadata_2025_split huggingface dataset:
Colour‐Doppler ultrasound imaging as a laparoscopy substitute to count corpora lutea in superovulated sheep
Authors: Pinto PHN , Bragança GM , Balaro MFA , Arashiro EKN , dos Santos GB , de Souza GN , Souza‐Fabjan JMG , Da Fonseca JF , Brandão FZ 
Published: October 2017

ContentsThis study evaluated colour‐Doppler ultrasound imaging (UI) as a substitute for laparoscopy to count the corpora lutea (CL) in superovulated sheep. Twenty‐five Santa Ines ewes were superovulated three times at 21‐day intervals. Corpora lutea were counted by colour‐Doppler UI (CLDOPPLER) 6 days after each superovulation and confirmed by laparoscopy (CLLAP) 12 hr later. The mean number of CL was similar for both techniques (2.1 ± 2.5 vs. 2.1 ± 2.7 for CLDOPPLER and CLLAP, respectively) with a significant positive correlation (r = .94; r2=.89). Colour‐Doppler UI effectively evaluated the ovarian response in superovulated ewes and efficiently identified animals that did not respond to superovulation.
DNA methylation and expression of imprinted genes are associated with the viability of different sexual cloned buffaloes
Authors: Ruan Z , Zhao X , Qin X , Luo C , Liu X , Deng Y , Zhu P , Li Z , Huang B , Shi D , Lu F 
Published: October 2017

ContentsThe DNA methylation of imprinted genes is an important way to regulate epigenetic reprogramming of donor cells in somatic cell nuclear transfer (SCNT). However, the effects of sexual distinction on the DNA methylation of imprinted genes in cloned animals have seldom been reported. In this study, we analysed the DNA methylation status of three imprinted genes (Xist, IGF2 and H19) from liveborn cloned buffaloes (L group, three female and three male), stillborn cloned buffaloes (S group, three female and three male) and natural reproduction buffaloes (N group, three female and three male), using bisulphite sequencing polymerase chain reaction (BS‐PCR). The expression levels of these imprinted genes were also investigated by quantitative real‐time PCR (QRT‐PCR). The DNA methylation levels of H19 were not significantly different among the groups. However, the Xist in female and IGF2 in male of the S group were found to be significantly hypomethylated in comparison with the same sexual buffaloes in L group and N group (p < .05). Furthermore, the expression levels of Xist, IGF2 and H19 in the stillborn female cloned buffaloes of S group were significantly higher than that of the female buffaloes in the L group and N group (p < .05). The expression levels of IGF2 and H19 in the stillborn male cloned buffaloes in the S group were significantly higher than that of the male buffaloes in the L group and N group (p < .05). These results indicate that Xist may be associated with the viability of female cloned buffaloes, and IGF2 may also be related to the viability of male cloned buffaloes.
Puncture and drainage of the subordinate follicles at timed artificial insemination prevents the risk of twin pregnancy in dairy cows
Authors: López‐Gatius F , Hunter RHF 
Published: October 2017

ContentsThe objective of this study was to determine whether fluid drainage from the subordinate follicles by ovum pickup procedures prevents the risk of twin pregnancy without reducing the fertility of the cow. Lactating dairy cows with at least two follicles over 12 mm diameter located one on each ovary and selected from synchronized groups for fixed‐time insemination were assigned to a Control (n = 49) or Drainage (n = 49) group. The largest follicle was considered as the dominant follicle. Draining of all subordinate follicles (≥10 mm) was performed in the Drainage group. All drained follicles developed as a corpus luteum 7 days later. In the Control cows, the presence of two corpora lutea (55.1%) was lower (p = .003) than those in the Drainage cows (87.8%), whereas the incidence of twin pregnancies was 50% and 0% for the Control and Drainage groups, respectively (p < .001). Draining did not affect the pregnancy rate. These results indicate that puncture and drainage of the subordinate follicles at insemination may eliminate the risk of twin pregnancies and reduce the risk of subsequent pregnancy loss by increasing the incidence of additional corpora lutea.
Risk Mapping of Groundwater‐Drawdown‐Induced Land Subsidence in Heterogeneous Soils on Large Areas
Authors: Sundell Jonas , Haaf Ezra , Norberg Tommy , Alén Claes , Karlsson Mats , Rosén Lars 
Published: October 2017

AbstractGroundwater leakage into subsurface constructions can cause reduction of pore pressure and subsidence in clay deposits, even at large distances from the location of the construction. The potential cost of damage is substantial, particularly in urban areas. The large‐scale process also implies heterogeneous soil conditions that cannot be described in complete detail, which causes a need for estimating uncertainty of subsidence with probabilistic methods. In this study, the risk for subsidence is estimated by coupling two probabilistic models, a geostatistics‐based soil stratification model with a subsidence model. Statistical analyses of stratification and soil properties are inputs into the models. The results include spatially explicit probabilistic estimates of subsidence magnitude and sensitivities of included model parameters. From these, areas with significant risk for subsidence are distinguished from low‐risk areas. The efficiency and usefulness of this modeling approach as a tool for communication to stakeholders, decision support for prioritization of risk‐reducing measures, and identification of the need for further investigations and monitoring are demonstrated with a case study of a planned tunnel in Stockholm.
Is hearing impairment associated with HIV? A systematic review of data from low‐ and middle‐income countries
Authors: Ensink Robbert J. H. , Kuper Hannah 
Published: October 2017

AbstractObjectivesTo systematically review evidence on the prevalence and characteristics of hearing impairment among children and adults living with HIV in low‐ and middle‐income countries (LMIC).MethodsArticles were identified up to January 2016 through searching four electronic databases. Epidemiological studies conducted in LMIC that explored the association between HIV status and hearing loss, with or without an HIV‐uninfected comparison group, were eligible for inclusion. Results were screened and assessed for eligibility, and data were extracted by two reviewers, with discussion in the case of disagreement. Findings were narratively synthesised.ResultsThe search identified 638 unique references, of which 21 studies were included in the review, including 3491 people with HIV from 13 LMIC. There was lack of consistency in the definition used for hearing loss, making comparability across studies difficult. Among children with HIV, across the three studies that used a cut‐off of >15 dB in either ear, the prevalence of hearing loss ranged from 22 to 37%. Among the three studies that used >25 dB in either ear, the prevalence ranged from 32 to 39%. Among adults with HIV, for the five studies that used a threshold of >25 dB for either ear, the prevalence ranged from 10 to 43%. The prevalence of hearing impairment was significantly higher among people with HIV than in controls in eight of the ten studies that assessed this comparison. Conductive hearing loss was the most common type of hearing loss in children with HIV, while sensorineural hearing loss was more common in adults with HIV. There was a lack of evidence for an association between ART use and hearing loss, although there was some suggestion that late stage of HIV disease or low CD4 count was related to hearing loss. There were concerns about the quality of the studies included in the review.ConclusionsThe current evidence is suggestive of a high prevalence of hearing loss among people living with HIV compared to people without HIV, or to WHO estimates for the general population. More research is needed to better understand the aetiology of hearing loss in relation to HIV, and whether screening for and treatment of hearing loss can be effectively integrated into HIV treatment services needs further research.
Bilateral trust and trade: Evidence from China
Authors: Xing Weibo , Zhou Li‐An 
Published: October 2017

AbstractBy changing transaction costs, trust can be a determinant of interregional economic exchange. Based on data sets of bilateral trust and trade at provincial level in China, this study investigates the trust–trade relationship empirically. As a channel of affecting bilateral trade, bilateral trust is incorporated into gravity models. By controlling for institutional quality, labour migration and other economic indicators, the baseline results show that the bilateral trust is positively correlated with the bilateral trade significantly. The sensitivity tests using an alternative estimation of interprovincial trade in China also confirm this positive trust–trade relationship. In addition, we use an instrumental‐variable estimation to control for the endogeneity of bilateral trust, and find that the trust–trade relationship is robust. This relationship seems to reveal that improving bilateral trust can be a new channel of boosting bilateral trade.
ScvO2 changes after red‐blood‐cell transfusion for anaemia in cardiothoracic and vascular ICU patients: an observational study
Authors: Zeroual N. , Samarani G. , Gallais J. , Culas G. , Saour M. , Mourad M. , Gaudard P. , Colson P. H. 
Published: October 2017

Background and ObjectivesHaemoglobin threshold for transfusion has been significantly decreased, but haemoglobin plasma concentration may not be sufficient to assess the need of red‐blood‐cell (RBC) transfusion. Central venous oxygen saturation (ScvO2) is a clue of metabolic matching between O2 transport and consumption, which could help to assess when transfusion is appropriate once anaemia has been diagnosed in ICU patients.Materials and MethodsAdult patients admitted consecutively to a cardiothoracic and vascular ICU were included in a prospective, observational and single‐centre study over a 6‐month period (September 2014 to February 2015), provided they were transfused with RBC. Patients with active bleeding or in unstable condition were excluded. Haemoglobin and ScvO2 were collected through a central venous catheter before and after transfusion. In order to identify a ScvO2 threshold, analysis of ScvO2 changes after transfusion was performed.ResultsFifty‐three patients received 100 RBC transfusions. Haemoglobin at the time of transfusion was 7·2 g/dl [6·8–7·7], while ScvO2 was 66·9% [60–73]. A 5% increase in ScvO2 after transfusion has the best specificity and positive predictive values, with a ScvO2 threshold of 65%. After transfusion (RBC units, 2 [1‐2]), ScvO2 increased only in patients with ScvO2 ≤65%, from 58% [53–62] to 69% [64–73] (P < 0·001).ConclusionIn anaemic patients, RBC transfusion induced a significant increase in ScvO2, provided it was low before transfusion. A 65% cut‐off value of ScvO2 before transfusion showed good specificity and good positive predictive value for a 5% increase after transfusion.
Role of a Liquid Accumulator in a Passive Two-Phase Liquid Cooling System for Electronics: Experimental Analysis
Authors: Lamaison Nicolas , Amalfi Raffaele L. , Marcinichen Jackson B. , Thome John R. , Salamon Todd 
Published: October 2017

Gravity-driven two-phase liquid cooling systems using flow boiling within micro-scale evaporators are becoming a game-changing solution for electronics cooling. The optimization of the system’s filling ratio can however become a challenging problem for a system operating over a wide range of cooling capacities and temperature ranges. The benefits of a liquid accumulator to overcome this difficulty are evaluated in the present paper.
An experimental thermosyphon cooling system was built to cool multiple electronic components up to a power dissipation of 1800 W. A double-ended cylinder with a volume of 150 cm3 is evaluated as the liquid accumulator for two different system volumes (associated to two different condensers).
Results demonstrated that the liquid accumulator provided robust thermal performance as a function of filling ratio for the entire range of heat loads tested. In addition, the present liquid accumulator was more effective for a small volume system, 599 cm3, than for a large volume system, 1169 cm3, in which the relative size of the liquid accumulator increased from 12.8 % to 25% of the total system’s volume.
Effects of Build-Up Material Properties on Warpage Dispersion of Organic Substrates Caused by Manufacturing Variations
Authors: Okamoto Keishi , Kohara Sayuri , Mori Hiroyuki 
Published: October 2017

In large-die (20mm and above) flip-chip packaging applications such as high-end processors, the organic substrates have been widely used. In most cases, they are double-sided multi-layer printed wiring boards. The substrates mainly consist of glass-reinforced rigid core, build-up film resin layers and copper trace patterns. During chip attaching process, the substrates are warped due mainly to the unbalance in copper loading ratio of the build-up layers between the front and the back of the core layer. A common practice for minimizing the warpage of a substrate is to balance its copper loading as much as possible at its design stage. However, the thickness of each build-up layer and trace pattern can shift from its designed value due to fluctuation in process conditions during manufacturing. Consequently, the substrate warpage becomes larger than the minimized value, since the copper loading is no longer balanced. One of the possible solutions for this challenge is to minimize the errors in manufacturing process. Another solution is to make the substrates more resilient to the manufacturing variations. The latter can be performed at the design stage. The substrates can be made resilient by minimizing the warpage deviation when the thickness of the build-up layer and trace pattern are varied.
In this paper, we have found that the warpage dispersion can be reduced by the build-up material properties which are the key components in balancing the front and back build-up layers. To study the effect of the build-up material properties, we performed dispersion analyses using the multilayered beam model. The analyses results showed a minimum in warpage dispersion when the coefficient of thermal expansion (CTE) of build-up materials is varied at a fixed Young’s modulus. They also show that the warpage dispersion decreases with decreasing Young’s modulus of build-up materials.
The analyses are also done by Monte Carlo simulation with finite element analyses (FEA) so that the analyses can be applied to more complex substrates made for actual packages. The results of Monte Carlo simulations were consistent with those of obtained by the multilayered beam model. The values in build-up material for minimizing the warpage dispersion are in realistic range. In summary, we showed that the organic substrates can be made resilient to manufacturing variations by choosing build-up materials with appropriate material properties which minimize the warpage dispersion.
Thermo-Optic Tuning Efficiency of Micro Ring Resonators on Low Thermal Resistance Silicon Photonics Substrates
Authors: Lei Shenghui , Shen Alexandre , Enright Ryan 
Published: October 2017

Silicon photonics has emerged as a scalable technology platform for future optotelectronic communication systems. However, the current use of SiO2-based silicon-on-insulator (SOI) substrates presents a thermal challenge to integrated active photonic components such as lasers and semiconductor optical amplifiers due to the poor thermal properties of the buried SiO2 optical cladding layer beneath these devices. To improve the thermal performance of these devices, it has been suggested that SiO2 be replaced with aluminum nitride (AlN); a dielectric with suitable optical properties to function as an effective optical cladding that, in its crystalline state, demonstrates a high thermal conductivity (∼100× larger than SiO2 in current SOI substrates).
On the other hand, the tuning efficiencies of thermally-controlled optical resonators and phase adjusters, crucial components for widely tunable lasers and modulators, are directly proportional to the thermal resistance of these devices. Therefore, the low thermal conductivity buried SiO2 layer in the SOI substrate is beneficial. Moreover, to further improve the thermal performance of these devices air trenches have been used to further thermally isolate these devices, resulting in up to ∼10× increase in tuning efficiency.
Here, we model the impact of changing the buried insulator on a SOI substrate from SiO2 to high quality AlN on the thermal performance of a MRR. We map out the thermal performance of the MRR over a wide range of under-etch levels using a thermo-electrical model that incorporates a pseudo-etching approach. The pseudo-etching model is based on the diffusion equation and distinguishes the regions where substrate material is removed during device fabrication. The simulations reveal the extent to which air trenches defined by a simple etch pattern around the MRR device can increase the thermal resistance of the device.
We find a critical under-etch below which no benefit is found in terms of the MRR tuning efficiency. Above this critical under-etch, the tuning efficiency increases exponentially. For the SiO2-based MRR, the thermal resistance increases by ∼7.7× between the un-etched state up to the most extreme etch state. In the unetched state, the thermal resistance of the AlN-based MRR is only ∼4% of the SiO2-based MRR. At the extreme level of under-etch, the thermal resistance of the AlN-based MRR is still only ∼60% of the un-etched SiO2-based MRR. Our results suggest the need for a more complex MRR thermal isolation strategy to significantly improve tuning efficiencies if an AlN-based SOI substrate is used.
Thermomechanical Reliability Challenges and Goals and Design for Reliability Methodologies for Electric Vehicle Systems
Authors: Huitink David 
Published: October 2017

With the anticipated growth in the electric vehicle market, advances in power electronics used in electric drivetrain, battery charging systems, etc. are delivering higher power densities, and with them, associated thermal challenges for operation in relatively closed vehicular systems. As such, the framework of reliability qualifications of electronic devices need to be reconsidered as system needs have moved beyond typical consumer electronic device needs, such as laptops or entertainment devices, where safe operation and longevity is essential to electric vehicle market viability. This work provides an overview of the reliability challenges associated with the operating environments and characteristics of power inverters in electric vehicles, particularly with respect to thermomechanical stresses. When considering the acceleration models presumed by the AEC Q100 specification for automotive electronics qualification, it is shown that inconsistencies in acceleration model form result in lack of clarity of how grades are chosen for different vehicle applications. Furthermore, the differences in vehicle drive cycles among user types show that service vehicles may have the most challenge to reliable operation, particularly in cold weather climates.
As an alternative metric for determining reliability in cyclic stresses, a novel test methodology for correlating solder fatigue life (and other thermomechanical failure modes) is proposed. The mechanical test for electronic packages is capable to disentangle the effects of temperature and design from the thermal cycling reliability such that the fundamental physics of failure can be extracted in a systematic fashion, and thereby develop better physics-based reliability acceleration models. Moreover, this novel approach enables the determination of independent stress to failure metrics that can translate risk across design and operating conditions for different system layouts without the need for multiple qualification tests.
Reliability of SAC 305 Solder Interconnects on Double-Sided Flexible Printed Circuit Board Using X-Ray Micro-CT
Authors: Lall Pradeep , Goyal Kartik 
Published: October 2017

Flexible electronics provide new design options not afforded by rigid electronics in a variety of applications including wearable electronics, robotics and automotive systems. However, the processes for the manufacturing of complex electronic assemblies using fine-pitch components are not as well developed as those for rigid electronics. The lack of structural rigidity of flexible printed circuit cards requires attention to assembly configuration for double-sided flexible assemblies. In addition, mechanisms are needed to compensate for the deformation and warpage of the flexible substrate and components during assembly. In this paper, the stresses in solder joints of double-sided flexible assemblies have been measured during thermal excursions using x-ray micro-computed tomography in conjunction with digital volume correlation. The method allows for non-invasive measurement and does not require cross-sectioning of the part for the purpose of deformation and strain measurement. In addition, the measurements are not limited to the joints in the line of sight. The three-dimensional measurements of deformation and strain have been visualized on the geometry of the solder joints in the package. Digital volume correlation (DVC) method has been used to find the displacements and strains in interconnects of operational electronics. The x-ray microscopic computed tomography (μCT) system has been used to generate the 16 bit digital volume data. The x-ray detector has ability to image the x-ray attenuation of x-rays through the object. Reliability testing of SAC 305 solder interconnects has been performed on double-sided flexible circuit board using x-ray μCT by heating the package to 100°C. The flexible circuit board used in this experiment is of BGA 256-144 combination, two packages, A-PBGA256-1.0mm-17mm and A-CABGA144-1.0mm-13mm.
A 3D printed fixture has also been used to support the flexible board and keep it flat while in the CT scan machine. The reference and deformed scans are then re-constructed 3D using Volume Graphics, and Digital Volume Correlation performed using MATLAB modules. Reliability of double-sided flexible printed circuit boards will be discussed and any crack, defects, or deformation in the solder interconnectivity which might occur while heating the package on flexible board is presented. The solder joint strains during thermal excursions are also compared between the flexible and rigid printed circuit assemblies.
Mutations within
embCAB
Are Associated with Variable Level of Ethambutol Resistance in Mycobacterium tuberculosis Isolates from China
Authors: Sun Qing , Xiao Tong-yang , Liu Hai-can , Zhao Xiu-qin , Liu Zhi-guang , Li Ya-nan , Zeng Hao , Zhao Li-li , Wan Kang-lin 
Published: October 2017

ABSTRACT

The EmbCAB proteins have been considered a target for ethambutol (EMB). Mutations in
embCAB
are known to confer most EMB resistance. However, the knowledge about the effects of
embCAB
mutations on the EMB resistance level and about the role of mutation-mutation interactions is limited in China. Here, we sequenced
embCAB
among 125
Mycobacterium tuberculosis
isolates from China and quantified their EMB MICs by testing growth at 10 concentrations. Furthermore, a multivariate regression model was established to assess the effects of both individual mutations and multiple mutations. Our results revealed that in China, 82.6% of EMB-resistant isolates (71/86 isolates) harbored at least one mutation within
embCAB
. Most of the mutations were located in the
embB
and
embA
upstream region. Several individual mutations and multiple mutations within this region contributed to the different levels of EMB resistance. Their effects were statistically significant. Additionally, there was an association between high-level EMB resistance and multiple mutations.