逻辑分析仪:超越1和0的世界

逻辑分析仪的发展早已经超出了帮助工程师观察时序图和1/0图样的阶段.多种多样的信息显示、为数众多的触发选择和使用方便的探头都使得这些台式的仪器变成设计数字设备的任何人员所必备的测量手段.     

应对电池管理的挑战

与某些只需简单的电流源即可完成再充电的电池不同,锂离子电池有着特殊的需求,为满足需要各半导体厂商推出了种类繁多的IC.半导体业界将这些产品归入"电源管理"或"电池管理"一类.尽管电池看上去象简单的双端器件,但用户必须注意使用方法,才能从中汲取最大的电力.     

Identification of critical control points using water quality as an indicator of hygiene for artisanal fisheries on Lake Malawi

Fish are a highly perishable commodity, and unhygienic fresh fish supply chains have been documented over the past two decades in sub‐Saharan Africa. Fishers spend long hours on boats with no provision of sanitary facilities, and even after landing, they are often in environments without sanitary facilities. The purpose of the present study was to explore the impacts of water, sanitation and hygiene practices in an artisanal fishery on food safety by analysing water samples in close contact with fresh fish at various checkpoints from capture to sale at the local market along the shores of Lake Malawi (Malawi). The four checkpoints included (a) fishing boats at the fishing ground before fishing commenced (n = 85); (b) in the same boats at the landing site before offloading fresh fish (n = 85); (c) with fresh fish transporters at the landing site (n = 71); and (d) among vendors at the market (n = 63). Escherichia coli was found in a high percentage of samples at each of the four checkpoints during the dry, wet and cold seasons. The highest risk for contamination (represented by E. coli concentrations) was the transition from transport to vendor, regardless of the season during which the samples were taken. The product value chain demands food safety. The results of the present study have potential applications in informing future interventions to develop behavioural change strategies regarding handwashing and toileting practices, norms unique for highly mobile fishing communities through the integration of hardware and software solutions and using better‐quality water to store fish on the boat, in transport and at the market.     

Myocardial infarction and percent arteriographic stenosis of culprit lesion: report from the Program on the Surgical Control of the Hyperlipidemias (POSCH)

Domestic violence is a significant public health issue affecting women. Numerous medical organizations have recommended that routine screening of women be conducted to assist in the prevention, identification, and care for victims of violence. This article examines the scope of domestic violence in women, reviews ways to recognize abuse, examines the potential impact of abuse upon health and discusses the management of victims.     

Determination of β-lactam residues in foodstuffs of animal origin using supported liquid membrane extraction and liquid chromatography–mass spectrometry

β-Lactams have been used extensively both in human and veterinary medicine practices. In veterinary medicine, they are used mainly as growth promoters as well as chemotherapeutic and prophylactic agents. The occurrence of β-lactam residues in foodstuffs is a serious health hazard. In this work, a sample purification and enrichment technique involving the use of supported liquid membrane have been developed for β-lactams in milk, kidney and liver tissues. The liquid membrane made of n-undecane:di-n-hexyl ether (1:1) was used to enrich a mixture of four β-lactams namely, ampicillin, cloxacillin, penicillin V and penicillin G. Separation and detection of the enriched β-lactam extracts were performed using a high performance liquid chromatography coupled to a mass spectrometer operating under positive ion electrospray mode (LC–PI–ESI–MS). The detection limits (DLs) obtained were found to be 1 ng/kg for penicillin G and penicillin V in kidney and liver tissues and 0.7 μg/L in milk. For ampicillin, the DLs were found to be 1.4 μg/kg in kidney and liver tissues and 1.7 μg/L in milk. Limits of quantification based on a minimal value of the signal-to-noise ratio of 10, were estimated to be 1.1 and 0.01 for penicillin G in kidney and liver tissues, respectively, while for penicillin V it was 0.4 and 0.01 for kidney and liver tissues, respectively. The DL values obtained using this approach were found to be 2–3 order of magnitudes lower than the stipulated tolerance levels as set by the EU and FDA.     

An in vitro model for infection with Leishmania major that mimics the immune response in mice

By using a primary in vitro response specific for Leishmania major, normal T cells from resistant CBA/CaH-T6J and susceptible BALB/c mice commit to a Th1 and a Th2 response, respectively. Since commitment occurred, we measured the production of gamma interferon (IFN-gamma), interleukin-1 (IL-1), IL-2, IL-4, IL-5, IL-10, and IL-12, prostaglandin E2 (PGE2), transforming growth factor beta (TGF-beta), and nitric oxide in the first 7 days of the response to identify factors that are critical for Th1 and Th2 development. While cells from resistant CBA mice produced more IFN-gamma, IL-10, and nitric oxide, cells from susceptible BALB/c mice produced more IL-1alpha, IL-5, PGE2, and TGF-beta. Although substantial amounts of IL-12 were detected, IL-12 did not associate with either Th1 or Th2 development. We did not anticipate that cells from resistant CBA mice would make more IL-10 in vitro. However, this also occurred in vivo since CBA mice produced substantial amounts of IL-10 following infection with L. major. Moreover, adding anti-IL-10 to primary in vitro responses enhanced production of IFN-gamma and nitric oxide by cells from CBA and BALB/c mice. Therefore, IL-10 cannot be regarded as a cytokine that associates with susceptibility to infection with L. major. Finally, the data presented here suggest that a collection of factors that can be produced by accessory cells influence Th commitment (e.g., IL-1, PGE2, and TGF-beta favor Th2 development).