The effectiveness of ozone and acidulant treatments in extending the refrigerated shelf life of fresh-cut potatoes

Abstract: The objective of the study was to determine the effectiveness of acidulant dip treatments (with or without aqueous ozone) to reduce enzymatic browning and to extend the shelf life of fresh‐cut potato slices during refrigerated storage (4 °C) for 28 d. Potato slices subjected to aqueous ozone (2 ppm) had significantly (P≤ 0.05) higher L‐values and lower a‐values, but ozone did not appear to have any effect on aerobic plate counts (APCs) or polyphenol oxidase (PPO) activity. NatureSeal (NS) and sodium acid sulfate (SAS) were the most effective acidulant treatments in reducing browning (significantly [P≤ 0.05] higher L‐values, lower a‐values, and browning index values) regardless of ozone treatment. NS and SAS also had lower PPO activity compared to other treatments on days 0 and 28, and significantly (P≤ 0.05) lower APCs (≤2.00 log CFU/g) over refrigerated storage. Therefore, the SAS treatment was comparable to NS, a commercially available product, and showed promise as an effective antibrowning dip to reduce browning and spoilage in fresh‐cut potato products. Practical Application: A 1% SAS dip treatment which included 1% citric and 1% ascorbic acid was found to be an effective antibrowning dip for fresh‐cut potatoes along with NatureSeal®'s PS‐10, compared to other treatments. They were both effective in maintaining low microbial counts over refrigerated storage. Additionally, aqueous ozone washes (2 ppm) showed significant benefits to reduce browning; however, ozone did not affect microbial counts or PPO enzyme activity. Therefore, the SAS treatment could have potential use in the fruit and vegetable industry to reduce browning and spoilage in fresh‐cut potato products.     

未建模动态对Buck变换器滑模控制系统的影响分析

研究传感器未建模动态对Buck变换器滑模控制系统的性能影响, 提出一种基于奇异摄动理论的稳定性和输出电压谐波分析的新方法.给出滑模控制器的参数整定方法, 选取传感器的上升时间作为摄动时间, 建立其未建模动态的奇异摄动模型, 在多时间尺度框架下, 揭示传感器稳定输出与摄动时间的影响关系.在此基础上, 构造一个类Lyapunov函数分析未建模动态对整个闭环控制系统的稳定性影响, 证明未建模动态诱发谐波的必然性.针对输出电压的谐波, 在频域内利用描述函数法推导出未建模动态摄动时间与其谐波幅值和频率的数学影响关系.仿真结果验证所提方法的正确性和有效性.     

向优化头发调理剂进军

研究了几种聚季铵盐材料和硅氧烷乳液相互之间的协合作用。建立了一套新方法,以测定头发上沉积的硅氧烷的含量。研究结果表明,配方师应根据不同地域开发出适合人们独特发质的产品。     

Improved Gap Estimates for Simulating Quantum Circuits by Adiabatic Evolution

We use elementary variational arguments to prove, and improve on, gap estimates which arise in simulating quantum circuits by adiabatic evolution. Partially supported by the National Science Foundation under Grant DMS-0314228 and by the National Security Agency and Advanced Research and Development Activity under Army Research Office contract number DAAD19-02-1-0065.     

Soluble adhesion molecules in CSF are increased in children with severe head injury

Leukocyte-endothelial adhesion molecules, critical to the development of acute inflammation, are expressed in brain as part of the acute inflammatory response to traumatic brain injury (TBI). We measured the concentrations of the adhesion molecules P-selectin, ICAM-1, E-selectin, L-selectin, and VCAM-1 in ventricular cerebrospinal fluid (CSF) from children with severe TBI (Glasgow coma score < 8) and compared these findings with those from children with bacterial meningitis. P-selectin, an adhesion molecule associated with ischemia/reperfusion, was increased in children with TBI versus meningitis and control. Univariate and multivariate regression analyses demonstrated associations between CSF P-selectin and child abuse and age of < 4 years, and a significant, independent association between CSF intercellular adhesion molecule-1 (ICAM-1) and child abuse. These results are consistent with a specific acute inflammatory component to TBI in children. Future studies of secondary injury mechanisms and therapy after TBI should assess on the roles of P-selectin and ICAM-1 in injury and repair processes in brain after TBI.     

Decomposing words into their constituent morphemes: Evidence from English and Hebrew.

Participants segmented and shifted a sequence of letters from a source word to a target word and then named the product aloud. Morphemic and nonmorphemic letter sequences (e.g., EN) from phonemically matched words such as HARDEN and GARDEN were compared. In 4 experiments, naming latencies were faster for morphemic sequences than their nonmorphemic controls in both English, in which the morphemic status of the shifted sequence was varied and sequences were appended after the base morpheme (linearly concatenated), and in Hebrew, in which morphological transparency of the root (base morpheme) was varied and 1 morpheme was infixed inside the other (nonconcatenative) so that the phonological and orthographic integrity of the morphemic constituents was disrupted. Moreover, the likelihood with which both affixes and bases combine to form words influenced segment shifting times. In conclusion, skilled readers are sensitive to the morphological components of words whether or not they form contiguous orthographic or phonological units. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Family influences on school achievement in low-income, African American children.

The authors examined the achievement-related beliefs and behaviors of parents of economically disadvantaged African American youth, and the relations among parental factors and children's academic self-concept and achievement. Forty-one children and their primary caregivers were interviewed. Parents reported on their academic-related beliefs and behaviors. Children completed measures of academic self-concept and 2 standardized achievement tests: 1 during the summer and 1 at the end of the following school year. Significant and positive relations were found between parental belief and behavior measures within the domains of reading and math; however, parental beliefs were more strongly linked with child outcomes than were parents' achievement-oriented behaviors. The relation between parental beliefs and child outcomes was not mediated by children's academic self-concept. Results are discussed in light of models of family influences on achievement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Initial evaluation of a real-world Internet smoking cessation system.

To significantly reduce smoking prevalence, treatments must balance reach, efficacy, and cost. The Internet can reach millions of smokers cost-effectively. Many cessation Web sites exist, but few have been evaluated. As a result, the potential impact of the Internet on smoking prevalence remains unknown. The present study reports the results, challenges, and limitations of a preliminary, large-scale evaluation of a broadly disseminated smoking cessation Web site used worldwide (QuitNet). Consecutive registrants (N=1,501) were surveyed 3 months after they registered on the Web site to assess 7-day point prevalence abstinence. Results must be interpreted cautiously because this is an uncontrolled study with a 25.6% response rate. Approximately 30% of those surveyed indicated they had already quit smoking at registration. Excluding these participants, an intention-to-treat analysis yielded 7% point prevalence abstinence (for the responders only, abstinence was 30%). A range of plausible cessation outcomes (9.8%-13.1%) among various subgroups is presented to illustrate the strengths and limitations of conducting Web-based evaluations, and the tensions between clinical and dissemination research methods. Process-to-outcome analyses indicated that sustained use of QuitNet, especially the use of social support, was associated with more than three times greater point prevalence abstinence and more than four times greater continuous abstinence. Despite its limitations, the present study provides useful information about the potential efficacy, challenging design and methodological issues, process-to-outcome mechanisms of action, and potential public health impact of Internet-based behavior change programs for smoking cessation.     

Cerebrovascular response in infants and young children following severe traumatic brain injury: a preliminary report

PURPOSE: Endotoxin (lipopolysaccharide [LPS])-induced systemic organ injury leads to disruption of normal systemic organ metabolic processes, which are manifest clinically by signs of accelerated anaerobic metabolism (e.g., tissue acidosis and hyperlactatemia) and altered VO2-DO2 relationships. The association of increased anaerobic metabolism with VO2-DO2 alterations has led to the notion that ischemia/ reperfusion (I/R) injury may be a prerequisite for the development of VO2-DO2 alterations during endotoxemia. However, in contrast to sepsis, in which oxygen consumption is often increased, oxygen consumption is severely decreased after I/R injury. Based on these observations, we hypothesized that I/R injury would result in systemic organ VO2-DO2 alterations, which are distinct from those that occur in sepsis. MATERIALS AND METHODS: We used the in situ autoperfused feline ileal preparation to simultaneously examine microvascular permeability, reflected as the ileal lymph to plasma protein concentration ratio (CL/CP), and ileal VO2-DO2 relationships after either intravenous LPS (2.0 mg/kg; n = 5) or I/R injury (n = 5), and in matching controls (n = 5). RESULTS: As expected, all LPS-treated and I/R-injured animals were found to have extensive ileal histological damage and marked increases in the CL/CP compared with controls (0.315 +/- 0.009 and 0.329 +/- 0.034, respectively, v 0.097 +/- 0.009; P < .001, both comparisons). In addition, the critical DO2 (DO2c) was elevated, and the critical oxygen extraction was decreased in both the I/R and LPS groups relative to controls. However, as initially hypothesized, the VO2 at the critical DO2 was markedly decreased in the I/R group compared with that of the LPS group. CONCLUSIONS: These data indicate that I/R injury is insufficient to account for the systemic organ VO2-DO2 alterations that occur with LPS injury.