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HIV-prevention measures specific to injection drug users (IDUs), such as opioid substitution treatment and needle-and-syringe programs, are not provided in many countries where injection drug use is endemic. We describe the incidence of diagnosed HIV infection in IDUs and the availability and coverage of opioid substitution and needle-and-syringe programs in the European Union and 5 middle- and high-income countries. Countries with greater provision of both prevention measures in 2000 to 2004 had lower incidence of diagnosed HIV infection in 2005 and 2006.In many countries where injection drug use is endemic, structural and legal difficulties preclude the provision of HIV-prevention measures specific to injection drug users (IDUs), such as opioid substitution treatment and needle-and-syringe programs.18 To determine whether there was an association between HIV incidence among IDUs and IDU-specific HIV-prevention measures, we compared the provision of IDU-specific prevention measures (“harm reduction” measures) to IDUs from 2000 to 2004 with diagnosed HIV incidence among IDUs from 2005 to 2006 in the European Union (EU) and 5 middle- and high-income countries.  相似文献   
23.
While searching for an object in a visual scene, an observer''s attentional focus and eye movements are often guided by information about object features and spatial locations. Both spatial and feature-specific attention are known to modulate neuronal responses in visual cortex, but little is known of the dynamics and interplay of these mechanisms as visual search progresses. To address this issue, we recorded from directionally selective cells in visual area MT of monkeys trained to covertly search for targets defined by a unique conjunction of color and motion features and to signal target detection with an eye movement to the putative target. Two patterns of response modulation were observed. One pattern consisted of enhanced responses to targets presented in the receptive field (RF). These modulations occurred at the end-stage of search and were more potent during correct target identification than during erroneous saccades to a distractor in RF, thus suggesting that this modulation is not a mere presaccadic enhancement. A second pattern of modulation was observed when RF stimuli were nontargets that shared a feature with the target. The latter effect was observed during early stages of search and is consistent with a global feature-specific mechanism. This effect often terminated before target identification, thus suggesting that it interacts with spatial attention. This modulation was exhibited not only for motion but also for color cue, although MT neurons are known to be insensitive to color. Such cue-invariant attentional effects may contribute to a feature binding mechanism acting across visual dimensions.  相似文献   
24.
A hyphenated LC-DAD-SPE-NMR setup in combination with on-line radical scavenging detection has been applied for the identification of radical scavenging compounds in extracts of Rhaponticumcarthamoides. After NMR measurements, the pure compounds were infused into a mass spectrometer. The technique enabled selective detection and identification of individual radical scavenging compounds without any prior off-line chromatographic steps. Seven compounds, namely, quercetagetin-7-beta-glucopyranoside (1), quercetagetin-7-(6"-acetyl-beta-glucopyranoside) (3), 6-hydroxykaempferol-7-beta-glucopyranoside (2), 6-methoxykaempferol-3-beta-glucopyranoside (4), 6-hydroxykaempferol-7-(6"-acetyl-beta-glucopyranoside) (5), chlorogenic acid (6), and beta-ecdysone (7), were identified in ethanol or aqueous extracts. Compound 5 is a new natural compound. Its radical scavenging activity was tested against DPPH radical and was found to be weaker than that of the reference antioxidants rosmarinic acid and Trolox.  相似文献   
25.
Caffeine alters the temporal dynamics of the visual BOLD response   总被引:4,自引:0,他引:4  
The blood oxygenation level-dependent (BOLD) responses to visual stimuli, using both a 1-s long single trial stimulus and a 20-s long block stimulus, were measured in a 4-T magnetic field both before and immediately after a 200-mg caffeine dose. In addition, resting levels of cerebral blood flow (CBF) were measured using arterial spin labeling. For the single trial stimulus, the caffeine dose significantly (p<0.05) reduced the time to peak (TTP), the time after the peak at which the response returned to 50% of the peak amplitude (TA50), and the amplitude of the poststimulus undershoot in all subjects (N=5). Other parameters, such as the full-width half-maximum (FWHM) and the peak amplitude, also showed significant changes in the majority of subjects. For the block stimulus, the TTP, TA50, and the time for the response to reach 50% of the peak amplitude (T50) were significantly reduced. In some subjects, oscillations were observed in the poststimulus portion of the response with median peak periods of 9.1 and 9.5 s for the single trial and block responses, respectively. Resting CBF was reduced by an average of 24%. The reproducibility of the results was verified in one subject who was scanned on 3 different days. The dynamic changes are similar to those previously reported for baseline CBF reductions induced by hypocapnia and hyperoxia.  相似文献   
26.
Enteral nutrition as an important component of modern treatment is mandatory for patients suffering from major burns. Regardless of the initial estimation of caloric requirements, actual daily volume of energy consumption may vary depending on the general condition of the patient and the side effects of enteral nutrition. The aim of our study was to investigate the relation between caloric value of enteral nutrition and treatment course. METHODS: The prospective study involved 103 adult patients treated in the Hospital of Kaunas University of Medicine for 2 degrees -3 degrees burns of 10-80% body surface area from 1 January 2001 till 31 December 2003. All patients received enteral nutrition during the acute phase. After the completion of the treatment, caloric value of enteral nutrition was estimated, and patients were divided into two groups: group A received more than 30 kcal/(kg 24 h); and group B, received less than 30 kcal/(kg 24 h). We compared patients' mortality, complication rate, and hospital stay time. RESULTS: The mortality of patients, who enterally received less than 30 kcal/(kg 24 h), was 32.6%, comparing to 5.3% mortality in patients who received 30 or more kcal/(kg 24 h) (p < 0.01). The caloric value of less than 30 kcal/(kg 24 h) increased the frequency of pneumonia by 2.0 times, and the frequency of sepsis by 1.8 times (p < 0.05). The duration of the treatment of survivors in this group was by 12.6 days longer (p = 0.01). CONCLUSIONS: The caloric value of enteral nutrition seems to be associated with patient mortality, complication rate, and treatment duration. The results of the treatment of patients who received more or 30 kcal/(kg 24 h) were much better. Because determined relationship may not be directly causal, further study is needed to determine whether active intervention to improve nutrition could improve outcomes.  相似文献   
27.
Clustered, regularly interspaced, short palindromic repeats (CRISPR)/CRISPR-associated (Cas) systems provide adaptive immunity against viruses and plasmids in bacteria and archaea. The silencing of invading nucleic acids is executed by ribonucleoprotein complexes preloaded with small, interfering CRISPR RNAs (crRNAs) that act as guides for targeting and degradation of foreign nucleic acid. Here, we demonstrate that the Cas9–crRNA complex of the Streptococcus thermophilus CRISPR3/Cas system introduces in vitro a double-strand break at a specific site in DNA containing a sequence complementary to crRNA. DNA cleavage is executed by Cas9, which uses two distinct active sites, RuvC and HNH, to generate site-specific nicks on opposite DNA strands. Results demonstrate that the Cas9–crRNA complex functions as an RNA-guided endonuclease with RNA-directed target sequence recognition and protein-mediated DNA cleavage. These findings pave the way for engineering of universal programmable RNA-guided DNA endonucleases.  相似文献   
28.
This paper deals with a computer-aided study of heart rate (HR) control during different sleep stages in 20 healthy volunteers and 75 ischemic heart disease (IHD) patients. In healthy subjects, the parasympathetic HR control was increased and the sympathetic control decreased during stages 1, 2, 3, and 4. REM sleep was characterized by a marked decrease in parasympathetic and a slight elevation in sympathetic contribution. Typical, “reduced” and “paradoxical” HP sleep patterns (HRSPs) were observed in IHD patients. The typical HRSP was similar to that observed in healthy subjects; the reduced HRSP was characterized by HR constancy, and the paradoxical HRSP by an HR increase in stages 3 and 4, and a decrease in REM sleep. The reduced HRSP was associated with the more frequent occurrence of cardiac abnormalities during REM sleep. HR oscillations during stage 2 depended on periodic apnoea episodes and were associated with cardiac abnormalities such as more frequent heart failure and cerebral blood flow disturbances, and overweight.  相似文献   
29.
Attending to a visual or auditory stimulus often requires irrelevant information to be filtered out, both within the modality attended and in other modalities. For example, attentively listening to a phone conversation can diminish our ability to detect visual events. We used functional magnetic resonance imaging (fMRI) to examine brain responses to visual and auditory stimuli while subjects attended visual or auditory information. Although early cortical areas are traditionally considered unimodal, we found that brain responses to the same ignored information depended on the modality attended. In early visual area V1, responses to ignored visual stimuli were weaker when attending to another visual stimulus, compared with attending to an auditory stimulus. The opposite was true in more central visual area MT+, where responses to ignored visual stimuli were weaker when attending to an auditory stimulus. Furthermore, fMRI responses to the same ignored visual information depended on the location of the auditory stimulus, with stronger responses when the attended auditory stimulus shared the same side of space as the ignored visual stimulus. In early auditory cortex, responses to ignored auditory stimuli were weaker when attending a visual stimulus. A simple parameterization of our data can describe the effects of redirecting attention across space within the same modality (spatial attention) or across modalities (cross-modal attention), and the influence of spatial attention across modalities (cross-modal spatial attention). Our results suggest that the representation of unattended information depends on whether attention is directed to another stimulus in the same modality or the same region of space.  相似文献   
30.
Hypoplastic left heart syndrome remains one of the most challenging pathologies in pediatric cardiac surgery. The surgical techniques, and anesthetic and intensive care management, have evolved over the last decades, which has resulted in improved outcomes. A central component in the postoperative management of hypoplastic left heart syndrome patients is to achieve an optimal balance between the pulmonary and systemic circulations. This article discusses the contemporary postoperative management of pulmonary and systemic circulations in detail.  相似文献   
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