利用参数DFM减少栅泄漏

初创公司Blaze DFM最近开发的技术大大缩小了设计和生产间的差距。据称公司刚刚推出的软件是业内第一个电可制造设计（DFM）的解决方案。由于是为芯片设计者编写的软件，能够分析设计中怎样应用每个晶体管，并允许选择修正CD减少泄漏电流或优化定时及使泄漏的变化更小。在90到65nm的设计中，已证实此方法可减少泄漏功率40％，泄漏变化60％，定时提高可达10％。     

Endogenous Particle Stabilization During Magnesium Integral Foam Production

The production of magnesium integral foam components with a dense shell and a porous core is investigated. High pressure casting methods are used where liquid magnesium mixed with a blowing agent is injected into a permanent steel mould. A compact shell develops due to fast cooling at the walls. Larger cooling times in the core allow the decomposition of the blowing agent and the evolution of a foam structure. The resulting integral foams show a high weight‐specific stiffness combined with high energy absorption capability. For the first time, foam stabilizing without additives is realized. Stabilization is by foaming during solidification with the primary α‐phase particles acting as obstacles slowing down cell wall thinning.     

Thyroid cancer after exposure to external radiation: a pooled analysis of seven studies

The thyroid gland of children is especially vulnerable to the carcinogenic action of ionizing radiation. To provide insights into various modifying influences on risk, seven major studies with organ doses to individual subjects were evaluated. Five cohort studies (atomic bomb survivors, children treated for tinea capitis, two studies of children irradiated for enlarged tonsils, and infants irradiated for an enlarged thymus gland) and two case-control studies (patients with cervical cancer and childhood cancer) were studied. The combined studies include almost 120,000 people (approximately 58,000 exposed to a wide range of doses and 61,000 nonexposed subjects), nearly 700 thyroid cancers and 3,000,000 person years of follow-up. For persons exposed to radiation before age 15 years, linearity best described the dose response, even down to 0.10 Gy. At the highest doses (> 10 Gy), associated with cancer therapy, there appeared to be a decrease or leveling of risk. For childhood exposures, the pooled excess relative risk per Gy (ERR/Gy) was 7.7 (95% CI = 2.1, 28.7) and the excess absolute risk per 10(4) PY Gy (EAR/10(4) PY Gy) was 4.4 (95% CI = 1.9, 10.1). The attributable risk percent (AR%) at 1 Gy was 88%. However, these summary estimates were affected strongly by age at exposure even within this limited age range. The ERR was greater (P = 0.07) for females than males, but the findings from the individual studies were not consistent. The EAR was higher among women, reflecting their higher rate of naturally occurring thyroid cancer. The distribution of ERR over time followed neither a simple multiplicative nor an additive pattern in relation to background occurrence. Only two cases were seen within 5 years of exposure. The ERR began to decline about 30 years after exposure but was still elevated at 40 years. Risk also decreased significantly with increasing age at exposure, with little risk apparent after age 20 years. Based on limited data, there was a suggestion that spreading dose over time (from a few days to > 1 year) may lower risk, possibly due to the opportunity for cellular repair mechanisms to operate. The thyroid gland in children has one of the highest risk coefficients of any organ and is the only tissue with convincing evidence for risk about 1.10 Gy.     

Gastric pacing improves emptying and symptoms in patients with gastroparesis

BACKGROUND & AIMS: No effective treatment is available for patients with gastroparesis refractory to standard medical therapy. The aim of this study was to investigate the effects of gastric pacing on gastric electrical activity, gastric emptying, and symptoms in patients with gastroparesis. METHODS: Nine patients with gastroparesis participated in this study. Four pairs of cardiac pacing wires were implanted on the serosa of the stomach. The protocol consisted of two portions: a temporary inpatient study period and an outpatient study for a period of 1 month or more. RESULTS: Gastric pacing entrained the gastric slow wave in all subjects and converted tachygastria in 2 patients into regular 3-cpm slow waves. Gastric emptying was significantly improved after the outpatient treatment with gastric pacing. The gastric retention at 2 hours was reduced from 77.0% +/- 3.3% to 56.6% +/- 8.6% (P < 0.05). Symptoms of gastroparesis were substantially reduced at the end of the outpatient treatment (1.51 +/- 0.46 vs. 2.84 +/- 0.61; P < 0.04). Eight of 9 patients no longer relied on jejunostomy tube feeding, and no adverse events were noted related to the pacing unit. CONCLUSIONS: Gastric pacing seems to be able to improve symptoms of gastroparesis and to accelerate gastric emptying in patients with gastroparesis. More controlled studies are necessary to further investigate the role of gastric pacing in clinical practice.     

Sediment-adsorbed total mercury flux through Yolo Bypass,the primary floodway and wetland in the Sacramento Valley,California

The fate and transport of mercury are of critical concern in lowland floodplains and wetlands worldwide, especially those with a history of upstream mining that increases the mobility of both dissolved and sediment-bound Hg in watersheds. A mass budget of total mercury (THg) quantifies sources and storage for particular areas — knowledge that is required for understanding of management options in lowland floodplains. In order to assess contaminant risk in the largest flood-control bypass, prime wetland, and restoration target in the Sacramento River basin, we estimated empirical relationships between THg, suspended sediment concentration (SSC), and streamflow (Q) for each of the major inputs and outputs using data from various publicly available sources. These relationships were improved by incorporating statistical representations of the dynamics of seasonal and intra-flood exhaustion (hysteresis) of sediment and mercury. Using continuous records of Q to estimate SSC suspended sediment flux and SSC to estimate THg flux, we computed the net transfer of sediment-adsorbed mercury through the Yolo Bypass over a decade, 1993–2003. Flood control weirs spilling Sacramento River floodwaters into the bypass deliver ~ 75% of the water and ~ 50% of the river's suspended sediment load, while one Coast Range tributary of the bypass, Cache Creek, contributes twice the THg load of the mainstem Sacramento. Although estimated sediment flux entering Yolo Bypass is balanced by efflux to the Sacramento/San Francisco Bay-Delta, there is much evidence of deposition and remobilization of sediment in Yolo Bypass during flooding. These factors point to the importance of the bypass as sedimentary reservoir and as an evolving substrate for biogeochemical processing of heavy metals. The estimates of mercury flux suggest net deposition of ~ 500 kg in the 24,000 ha floodway over a decade, dominated by two large floods, representing a storage reservoir for this important contaminant.     

Discontinuous Precipitation and Phase Stability In Re- and Ru-Containing Nickel-Base Superalloys

The phase stability of nickel-base superalloys has been investigated using a new in-house-designed alloy series with stepwise increased additions of Re and Ru at otherwise fixed atomic fractions of alloying elements. Results presented in this study are focused on the lesser-known topologically closed packed (TCP) formation of columnar colonies or so-called discontinuous precipitation. A detailed investigation of these colonies allowed for identifying compositional changes during the growth process and for providing a three-dimensional (3-D) illustration of the TCP phases within these colonies. The results were used to compare the colony growth process with existing growth models. Furthermore, the influence of Re and Ru on the appearance of discontinuous precipitation has been investigated by means of colony width and the effect on creep properties. Larson-Miller plots are given to illustrate the creep strength of directionally solidified samples with and without TCP colonies compared with single crystalline samples free from TCP colonies.     

The technology gap and the developing countries

Recently much more attention has been given to the application of Science and Technology to development in the developing countries. While analysing the role of science and technology in the development of these countries, it is useful to distinguish between “growth” and “development”. The progressive application and development of modern science and technology should be considered much more than a simple accumulation of useful information of know‐how (science) and know‐why (technology).

It is well known that 98 % of the world's R and D expenditures are concentrated in the rich countries which have different interests, different problems and seek different solutions than those in the developing countries. As the ability to analyse technical scientific and managerial problems has grown in the rich industrial countries, the poor low income countries have become increasingly dependent on technologies conceived and developed in the rich countries and not suitable for their needs and resource endowments.

In the light of this situation, it is suggested that the rich‐developed countries should reorient a substantial part of their expenditures on R and D so that some of the resulting advances in science and technology are directly geared to the problems of the less developed countries as pointed out in the U.N. World Plan of Action for the application of science and technology to development.     

The effect of compatibilization on the behavior of a polycarbonate/polymer liquid crystal blend

Polymer liquid crystalline materials (PLC) blended with engineering plastics (EP) have the potential to reduce viscosity and increase the modulus of the EP, particularly if the PLC is in a favorable fibrillar morphology. A major deficiency in these blends—as with many other immiscible polymeric systems—is poor failure properties. In this paper, polycarbonate (PC) and a rigid, all-aromatic commercial PLC are blended and a third resin, a copolymer of methyl methacrylate and N-methyl-dimethyl-glutarimide is included as a compatibilizing agent. Characterization of the binary and ternary blends is carried out using rheological, mechanical, morphological, and dynamic mechanical characterization techniques. Binary blends of PLC in a PC matrix result in an immiscible, nodular morphology with low failure stresses. The addition of the copolymeric compatibilizer—particularly one with reactive functionalities—is found to improve tensile strength and yield a fibrillar blend morphology. It is proposed that this may be due to the compatibilizer reducing interfacial tension and adhering to the blend phases, rather than by causing a major change in blend viscosity.     

Time to clinical stability in patients hospitalized with community-acquired pneumonia: implications for practice guidelines

CONTEXT: Many groups have developed guidelines to shorten hospital length of stay in pneumonia in order to decrease costs, but the length of time until a patient hospitalized with pneumonia becomes clinically stable has not been established. OBJECTIVE: To describe the time to resolution of abnormalities in vital signs, ability to eat, and mental status in patients with community-acquired pneumonia and assess clinical outcomes after achieving stability. DESIGN: Prospective, multicenter, observational cohort study. SETTING: Three university and 1 community teaching hospital in Boston, Mass, Pittsburgh, Pa, and Halifax, Nova Scotia. PATIENTS: Six hundred eighty-six adults hospitalized with community-acquired pneumonia. MAIN OUTCOME MEASURES: Time to resolution of vital signs, ability to eat, mental status, hospital length of stay, and admission to an intensive care, coronary care, or telemetry unit. RESULTS: The median time to stability was 2 days for heart rate (< or =100 beats/min) and systolic blood pressure (> or =90 mm Hg), and 3 days for respiratory rate (< or =24 breaths/min), oxygen saturation (> or =90%), and temperature (< or =37.2 degrees C [99 degrees F]). The median time to overall clinical stability was 3 days for the most lenient definition of stability and 7 days for the most conservative definition. Patients with more severe cases of pneumonia at presentation took longer to reach stability. Once stability was achieved, clinical deterioration requiring intensive care, coronary care, or telemetry monitoring occurred in 1% of cases or fewer. Between 65% to 86% of patients stayed in the hospital more than 1 day after reaching stability, and fewer than 29% to 46% were converted to oral antibiotics within 1 day of stability, depending on the definition of stability. CONCLUSIONS: Our estimates of time to stability in pneumonia and explicit criteria for defining stability can provide an evidence-based estimate of optimal length of stay, and outline a clinically sensible approach to improving the efficiency of inpatient management.