bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical features and risk factors for developing varicella zoster virus dissemination following hematopoietic stem cell transplantation
Authors: Umezawa Y. , Kakihana K. , Oshikawa G. , Kobayashi T. , Doki N. , Sakamaki H. , Ohashi K. 
Published: January 2014

AbstractBackgroundWe retrospectively analyzed 80 instances of varicella zoster virus (VZV) disease in 72 patients who underwent allogeneic hematopoietic stem cell transplantation (HSCT) and examined the clinical differences between localized and disseminated disease. Risk factors for developing VZV dissemination were also evaluated.ResultsOf the 80 instances, 54 instances were localized diseases and 26 were disseminated diseases. Patient characteristics did not differ significantly between the 2 groups, except for the first‐line therapy and the duration from symptom onset to treatment. In the disseminated group, intravenous acyclovir was used as the first‐line therapy more frequently, and more time elapsed before beginning antiviral therapy compared with the localized group. In multivariate analyses, the duration from symptom onset to treatment was identified as an independent risk factor that significantly affected the development of VZV dissemination. Gender, total body irradiation, and chronic graft‐versus‐host disease, of which the latter 2 factors were reported as risk factors for the development of VZV disease after HSCT, did not affect the development of VZV dissemination.ConclusionOur results suggest that VZV infection or reactivation may easily progress to viremia with delayed use of antiviral agents and may result in VZV dissemination in immunocompromised patients.
Course and treatment of chronic hepatitis E virus infection in lung transplant recipients
Authors: Pischke S. , Greer M. , Hardtke S. , Bremer B. , Gisa A. , Lehmann P. , Haverich A. , Welte T. , Manns M.P. , Wedemeyer H. , Gottlieb J. ,   the Hepatitis E study group
Published: January 2014

AbstractObjectivePersistent hepatitis E virus (HEV) infections have been described in various transplant cohorts. However, the frequency and the course of HEV infection in lung transplant recipients (Lu‐Tr) are not well defined.MethodsWe retrospectively analyzed serum from 95 Lu‐Tr for HEV RNA and anti‐HEV immunoglobulin‐G (IgG) (with the MP assay). Anti‐HEV seroprevalence was compared to that of 537 healthy individuals. Prospective HEV screening was subsequently initiated in Lu‐Tr.ResultsElevated liver enzymes were observed in 44/95 (46.3%) patients. Anti‐HEV IgG was present in 5/95 patients (5.3%), revealing a slightly higher prevalence compared to controls (2%, 11/537; P = 0.07). Chronic HEV infection with detectable viral replication was confirmed by polymerase chain reaction in 3 (3.2%) patients, all of whom demonstrated clinical and biochemical features of active liver disease (maximum alanine aminotransferase [ALTmax] 89, 215, and 270 IU/L, respectively). One patient had died from multi‐organ failure in combination with liver cirrhosis before HEV diagnosis. Two additional patients with chronic hepatitis E were identified during prospective screening (ALTmax 359 and 318 IU/L). All patients still alive commenced ribavirin therapy for 5 months, with dose adjustment (400–600 mg/day) according to renal function and hemoglobin level. Sustained resolution of HEV infection occurred in 2 patients. One patient is still under treatment, and the fourth died from graft failure considered unrelated to ribavirin therapy.ConclusionChronic hepatitis E should be considered in the differential diagnosis of elevated liver enzymes, which are commonly seen in Lu‐Tr. We observed 1 case of end‐stage liver cirrhosis and death in an HEV‐infected subject, who was not treated with ribavirin. Given this potentially devastating consequence, ribavirin therapy of persistent HEV infection appears to be acceptably safe and effective in Lu‐Tr. However, larger prospective studies are warranted.
Ocular and eyelid neoplasia in birds: 15 cases (1982–2011)
Authors: Rodriguez‐Ramos Fernandez Julia , Dubielzig Richard R. 
Published: January 2014

AbstractOcular and eyelid lesions are a common finding in birds; however, avian ocular and eyelid neoplasia is seldom reported. The purpose of this study was to record clinical and pathological data from cases of avian ocular neoplasia submitted to theComparativeOcularPathologyLaboratory ofWisconsin over a 29‐year period. A total of 284 avian ocular pathology cases from 1982 to 2011 were reviewed. Out of those, 15 were diagnosed with nine different ocular tumors (5.2%). Metastatic cancer to the globe was diagnosed in seven cases. Six of the metastatic cancers were diagnosed as lymphoma and one as papillary cystic carcinoma of respiratory epithelial origin, presumably originating in the sinus. Primary tumors were diagnosed in eight cases including three tumors of epithelial origin (undifferentiated carcinoma, multicystic adenoma, and pigmented iridociliary adenoma). A teratoid medulloepithelioma and a ganglioneuroma were presumptively diagnosed. A round cell tumor and squamous cell carcinoma were detected in conjunctival samples, and a teratoma was diagnosed from an episcleral sample.
Applications of Cold Plate Units With Micro-Channel for Cooling Electronics
Authors: Mashiko Koichi , Mochizuki Masataka , Goto Kazuhiko , Takahashi Makoto , Matsuda Masahiro , Horiuchi Yasuhiro , Nguyen Tien 
Published: January 2014

Until recently, effective cooling solutions with high performance were required especially in data-centers and super computers because of the huge and ever-increasing power consumption in these applications. Water cooling systems have been considered for use in the cooling of large scale data-centers and super computers.
For the cooling of super computer CPUs, a water cooling system using advanced cold plate technology is reconsidered. The thermal resistance of a cold plate for cooling the CPU is required to dissipate 80 to 100W of heat at 0.05 K/W. Also, in this application, the cold plate is required to be mechanically reliable in withstanding a cooling water pressure of 1MPa. We adopted a micro-channel structure as a heat transfer surface of this cold plate and developed a new brazing method so that the tips of the micro-channel fins are bonded to the inside of cover plate of the cold plate. In collaboration with a customer in charge of the design, we completed the water cooling unit consisting of cold plates, pipes and coupler manifold, assembled by brazing.
Finally, the high volume products were manufactured with reliability inspection (pressure test and helium leakage test) and used to effectively cool the CPUs of an advanced super computer, which was awarded the fastest super computer record.
Water cooling technology provides effective high capacity cooling in compact space limits, and has been widely used in applications like fiber laser machines and others. This paper describes the development of cold plate with micro-channels and its applications.
Investigation on the Multiple Jet Impingement Heat Transfer Using Al2O3-Water Nanofluid
Authors: Senkal Caner , Torii Shuichi 
Published: January 2014

In recent years, increasing demands for high performance electronic devices give rise to a necessity to remove enormous amount of heat fluxes from small areas. Uniform temperature distribution and sufficient heat transfer dissipation are crucial issues for proper operation of electronic components. To cope up with thermal management of high heat dissipation devices, an efficient cooling method is required. Jet impingement cooling is one of those promising candidates which can handle heat dissipation in an effective way due to its superior heat transfer rates. In this paper, Al2O3 nanofluid heat transfer characteristics are investigated experimentally. Particle diameter of 31nm Al2O3 is taken into consideration in experiments. Impingement surface (surface area:780mm2) were made from oxygen-free copper to simulate high heat flux dissipating electronic component.
The experimental results show that the suspended nanoparticles remarkably increase the convective heat transfer coefficient of the base fluid.. Nanofluids with particle volume fractions up to 4% can provide significant heat transfer enhancement, on the other hand, it has been found that high volume fractions (higher then 6%), is not appropriate for heat transfer enhancement under the free jet array configuration. Within the range of parameters considered in this study, experimental results indicated that maximum heat transfer coefficient can be obtained for the intermediate jet to heated target distance (around five times of jet diameter) and closely spaced jets (S/D = 3) for the particle volume fraction 2%. Closely spaced jets are particularly suitable for the electronics cooling applications with regards to provide temperature uniformity on the heated surface.
A Method for Failure Analysis for Devices With Simultaneous Imaging of Electron Emission and Near IR Thermoreflectance
Authors: Yazawa Kazuaki , Kendig Dustin , Christofferson James , Shakouri Ali 
Published: January 2014

Thermal characterization is useful for identifying the cause of circuit failures. Unusually high local temperatures can occur due to unexpected and localized power dissipation in a particular device, which was not anticipated nor designed in the device. Unintended high temperatures may be the source of circuit damage or it might be caused by the failure itself, such as a tiny short-circuit. However, it is often difficult to obtain enough information about the physical structure and characteristics of the circuit to clearly identify the cause of the failure. The method we present here is an imaging technique with both thermal distribution and emission intensity superimposed on a single image.
Thermoreflectance thermal imaging takes advantage of the differences in light reflectivity of the surface with a changing temperature. This relationship is quite linear in a typical temperature range of interest. Using 1300 nm wave length for the illuminating source, the metal circuitry of interest is directly observed through the almost transparent silicon substrate of a flip chip mounted device. With the same photo detecting imaging sensor, i.e. InGaAs junction array, the emission from the target device through the silicon substrate is also detected. If there are some local electron collisions, e.g. due to a current concentration at a defect or a tiny whisker, a localized excess energy by electron-electron collision yields the photon generation and emits an electromagnetic wave. The photons having a sufficient energy level at wavelength transparent to silicon, reach the photo detecting imaging sensor. With software processing and precise synchronization of the driving circuit, illumination, and imaging, we can separate the thermal signal from the emission and observe transient behavior on a nanosecond time scale. The time response is helpful in some cases to separate cause and effect. As an example, an unintended small short-circuit resulting from the fabrication process may be reproduced for a small number of samples. The emission would be observed first, followed by the thermal signal which propagates in time. Another example is for a circuit with low design margin, in this case only a single sample exhibits a difference between emission and/or thermal image while numbers of good samples are identical with respect to the emission and thermal image. This difference clearly indicates the location of a potential failure.
Analysis of 3D-Strain Singular Field Near the Corner of Si Chip Using Digital Image Correlation Method
Authors: Koguchi Hideo , Tsukada Yasuyuki , Kurahashi Takahiko 
Published: January 2014

Portable electronics devices such as mobile phone and portable music player become compact and improve their performance. High-density packaging technology such as CSP (Chip Size Package) and Stacked-CSP is used for improving the performance of devices. CSP has a bonded structure composed of materials with different properties. A mismatch of material properties may cause stress singularity, which lead to the failure of bonding part in structures.
In the present study, a strain singular field near inter-face edge in three-dimensional joints is investigated using digital image correlation method. A specimen which silicon chip was embedded in resin is used in experiment and tensile load is applied to the specimen. Photograph of specimen surface is taken before and after loadings by laser microscope. Displacement on the surface was evaluated by the digital image correlation method (DICM) using data of surface pattern on the specimen, which the cross correlation coefficients for surface pattern are maximized. Strain on surface of specimen is calculated by using the moving least square method. On the other hand, 3D element free Galerkin method is applied to compute the displacement and strain distribution in a three-dimensional model of the specimen. In the element free Galerkin method, the physical values, i.e., displacement, strain and stress, can be obtained by using the displacement data at node. In this research, strain distribution near the edge of interface is computed based on the element free Galerkin method. Finally, the strain distribution obtained by the digital image correlation method and the moving least square method is compared with that obtained by the element free Galerkin method. The intensity of strain singularity is determined numerically and experimentally.
Reliability Evaluation of a 3D SIC Package by the Combination of the SEM-DIC and the FEM
Authors: Ikeda Toru , Oka Masatoshi , Miyazaki Noriyuki 
Published: January 2014

Numerical methods such as the finite element method (FEM) have been used to evaluate the reliability of electronic packages. The accuracy of the analyses should be verified by some experimental measurements. In this study, we evaluated the thermal strain of a test chip for three-dimensional stacked integrated circuits (3D SIC) with both measurement and an analysis. First, the distribution of thermal strain on the cross-section of a test chip was measured using scanning electron microscope (SEM) and the digital image correlation. Then, the distribution of strain of the test chip was also analyzed by the FEM considering the viscoelastic material properties of underfill (UF) resin measured with the stress relaxation test and the elastic-plastic material properties of components measured with the nano-indentation tests. The accuracy of the nonlinear finite element analysis was verified using the strain measurements with the SEM-DICM.
A test specimen for the 3D SIC packages was built and cut out a part of the test specimen and polished its cross-section. We took digital images using a SEM (FEI Quanta 200) to measure the strain distributions on the cross-section of a specimen by the DICM. The specimen was subjected to thermal loading in a heat chamber. The temperature in the chamber was raised from 30° C to 130°C.
The FE analyses were carried out using MSC.Marc™. We assumed the initial temperature of the analysis to be 150°C, which was the curing temperature of the UF resin, and decreased the temperature to 30°C during 100 seconds. Then, the temperature was raised up to 130°C, which is the same with the experiment. We compared the numerical result with the measurement and modified the model of the FE analyses.
Experimental Measurement of Server Thermal Effectiveness for Compact Transient Data Center Models
Authors: VanGilder James W. , Pardey Zachary M. , Zhang Xuanhang (Simon) , Healey Christopher 
Published: January 2014

Server thermal mass can significantly affect the rate at which a data center heats up following a loss of cooling and moderate transient temperature fluctuations due to changing CPU utilization. Recently, a compact server model has been introduced which captures the effects of thermal mass while avoiding the impractical level of detail that would be required by an explicit representation of all relevant server components. Inputs to that model include server mass, overall effective specific heat, and a parameter called the “server thermal effectiveness”. The latter characterizes the server’s ability to transfer heat to/from the airstream passing through it and can take values between zero (no heat exchange) and one (maximum possible heat exchange). Server thermal mass is a physical property of a server and is not influenced by external factors.
In order to use the compact model for practical applications, we must experimentally measure the thermal effectiveness of actual servers. The present study reviews the compact model and describes the development of an experimental technique for measuring thermal effectiveness. The technique is validated using simple plate fin heat sinks in place of an actual server. This “server proxy” is sufficiently simple so that it can be modeled accurately in detail in CFD, providing well-controlled benchmark data. CFD and experimental measurements both yield a value of server thermal effectiveness of approximately 0.6, providing confidence in the model and measurement technique for the future characterization of actual servers.
Effect of Isothermal Aging on Microstructure and Creep Properties of SAC305 Solder: A Micromechanics Approach
Authors: Chauhan Preeti , Mukherjee Subhasis , Osterman Michael , Dasgupta Abhijit , Pecht Michael 
Published: January 2014

SnAgCu (SAC) solders undergo continuous micro structural coarsening during both storage and service. In this study, we use cross-sectioning and image processing techniques to periodically quantify the effect of isothermal aging quantitatively on phase coarsening and evolution, in SAC305 (Sn3.0Ag0.5Cu) solder. SAC305 alloy is aged for (24–1000) hours at 100°C (∼ 0.7–0.8Tmelt). The characteristic parameters monitored during isothermal aging include size, volume fraction, and inter-particle spacing of both nanoscale Ag3Sn intermetallic compounds (IMCs) and micronscale Cu6Sn5 IMCs, as well as the volume fraction of pure tin dendrites in SAC305 solder.
Effects of above microstructural evolution on secondary creep constitutive response of SAC305 interconnects were modeled using a mechanistic multiscale creep model. The mechanistic phenomena modeled include: (1) dispersion strengthening by coarsened nanoscale Ag3Sn IMCs and reinforcement strengthening by micronscale Cu6Sn5 IMCs, respectively; and (2) load sharing between pure Sn dendrites and the surrounding eutectic Sn-Ag phase.
The coarse-grained polycrystalline Sn micro structure in SAC305 solder was not captured in the above model because isothermal aging did not appear to cause any significant change in the initial grain morphology of SAC305 solder joints. The above model is shown to predict the drop in creep resistance due to the influence of isothermal aging on SAC305 solder joints.
A Minimal Order Model From Zero to High Frequencies for Finite-Element Based Analysis of General 3-D Electromagnetic Problems
Authors: Sheng Feng , Jiao Dan 
Published: January 2014

Modern integrated circuits (IC) and package design has scaled into the deep submicron regime and the nanometer regime. Fast and broadband frequency-domain electromagnetic analysis has become increasingly important. The large problem size encountered in the analysis of ICs and packages is a major challenge especially for a finite element method (FEM) based electromagnetic analysis.
To reduce the computational cost for large-scale electromagnetic analysis, model order reduction (MOR) methods have been developed to preprocess the huge linear system into reduced order models. However, in order to meet the modeling and simulation challenges arising from the IC and package design, existing MOR methods still have to overcome the following shortcomings. First, many existing MOR methods lack a closed-form error bound. Given an accuracy requirement, the model generated from existing methods may not be compact enough. Second, most of the existing reduced order models depend on frequency and right hand side. They lose efficiency when analyzing frequency-dependent problems with a large number of right hand sides. Last but not least, many existing MOR methods suffer from low frequency breakdown problem. Additional models have to be built if low frequency solutions, including DC solution, are required.
This paper proposes a minimal order model for any prescribed accuracy for the finite element based solution of general 3-D problems having arbitrary lossless/lossy structures and inhomogeneous materials. This model entails no theoretical approximations. It is frequency and right hand side independent, and hence can be employed for both fast frequency and right hand side sweep. Moreover, the model does not suffer from low-frequency breakdown and is accurate from zero to high frequencies. To facilitate the application of such a minimal order model, we have also developed an efficient algorithm to generate this model. Numerical experiments have demonstrated the accuracy and efficiency of the proposed method. In addition to frequency-domain analysis, the proposed model can also be used for fast time-domain analysis.
Analytic Optimization of Porous Medium Heat Sinks for Energy Efficiency and Minimum Mass
Authors: Trifale Ninad , Nauman Eric , Yazawa Kazuaki 
Published: January 2014

Use of microchannel heat sinks for high heat flux applications is substantial for thermal management and it is also critical for scalable power generation. For both applications, the energy efficiency consideration of the pump power is crucial. A number of models have been created that predict the performance as a function of the geometrical parameters, taking into account, the pressure loss over the length and volume constraints. Most of the approaches either involve sophisticated calculations incorporating fluid dynamics in channels, or have an analogy with the pin-fin model, which gives simpler calculations but considers only a single laminar flow regime for optimization. Even with the simplified models available, the geometrical impact on mass and pumping power is nonlinear and not apparent for optimization. We propose an optimization of porous medium heat sinks with respect to the heat transfer rate, mass, and pumping power. These are functions of the simplest geometric parameters, i.e. porosity, pore density, and length of the porous medium.
Considering large production, mass (cost of raw material) is nearly proportional to the cost of the heat sink, we consider minimizing the mass for indirectly minimizing the overall cost. The other factor for saving energy considered here is the pumping power. This connects to both the heat transfer rate and the power consumption to drive the fluid through the porous medium.
The optimization is performed for a specific value of porosity and length of the heat sink. The model considers the effect of flow through the porous medium and the effective thermal conduction as a function of combined conductivity of the solid ligaments and the fluid in pores.
An optimum coefficient of performance (COP) is found at over 90% of porosity for minimum mass, pumping work and maximum heat transfer. This mathematical expression of the model will give a quantifiable figure-of-merit to take into account the impact of the mass and the pumping power on the performance to cost ratio.