真空冷冻干燥乳酸菌的研究进展

介绍了真空冷冻干燥的原理,乳酸菌干粉发酵剂的生产工艺,影响乳酸菌冷冻干燥存活率的因素等,并对如何提高冷冻干燥菌种的存活率进行了探讨.认为影响乳酸菌存活的因素主要有菌种自身的因素、冻干对菌种的伤害以及保护剂的作用.故应该从以下两个方面深化研究:一是继续深入研究菌种的冻伤机理,设置合理的冷冻干燥程序;二是研发高效、经济的冷冻干燥保护剂和再水化剂,既要最大限度地保障菌种的存活率又要经济实用.     

胡萝卜的冷冻干燥

胡萝卜组织结构致密，不易自然干燥．一般的干燥方法容易失去营养成分，而冷冻干燥是最合适的干燥方法．本主要就冷冻干燥胡萝卜的原理、流程进行研究．     

BCP/COL/HCA骨组织工程支架的仿生制备

通过仿生合成、冷冻干燥及交联处理方法,制备出一种以双相磷酸钙、胶原和碳酸羟基磷灰石三组分为主要成分的新型三维骨组织工程支架。采用SEM、EDX和FTIR等测试技术对支架的性能特征进行分析。结果表明:制备的复合支架具有三维多孔的有序结构。双相磷酸钙作为力学支撑骨架有助于胶原网络基质形成特定的形状并使之具有一定的力学强度。在矿化过程中,羟基磷灰石矿物晶体在胶原的反应成核位点通过化学键合作用进行自组装。交联的胶原及其仿生矿化形成的碳酸羟基磷灰石可使支架具有良好的生物学性能,有望成为广阔临床应用前景的骨组织工程植入材料。     

盐酸小檗碱口腔速崩片的研制

研制盐酸小檗碱口腔速崩片.采用冷冻干燥法制得盐酸小檗碱口腔速崩片,考察其崩解性能.研制的盐酸小檗碱口腔速崩片崩解时间小于30 s,20 min的累积释药量大于80%,外形完整光滑.研制的盐酸小檗碱口腔速崩片具有良好的外形、崩解特性和释药性能.     

Experimental study on rehydration conditions of freeze-dried platelets

A rehydration process for freeze-dried human platelets was studied on 1 ml of samples. The effects of prehydration duration, prehydration temperature, an rehydration solution on the recovery rate, mean platelet volume （MPV）, and platelet distribution width （PDW） were investigated. The mass changes during the prehydration process were also studied. Three prehydration durations： 0, 1.5, and 3.5 h, and two rehydration solutions： platelet-poor plasma and phosphate-buffered saline （PBS）, were tested. It was found that： （1） the prehydration was of significance; （2） 1.5 h of prehydration had better effects than 3.5 h of prehydration; （3） as a rehydration solution, the platelet-poor plasma behaved better than the PBS. The impacts of prehydration duration and temperature on the results were studied. There was almost no difference between 35 and 37 ℃. Among all the prehydration durations tested, 15, 30, 60, 90, and 120 min, the best result was achieved with the time duration of 15 min. The weights of prehydrated platelets at the end of each test were measured and the water contents were calculated. After 15 min ofprehydration, the water contents in the samples were about （4.8±0.01）% and （5.27±0.29）% （w/w） corresponding to the conditions of 35 and 37 ℃, respectively. These results will be helpful for further studies on the freeze-drying of mammalian cells.     

香菇多糖冻干粉针剂的制备及质量评价

研究香菇多糖冻干粉针剂的处方及制备工艺,并对其进行质量评价．经预实验选定复合赋形剂及配比,实验考察其用量对制剂成型性的影响,用正交法筛选最优处方,以冷冻干燥法制备粉针剂,并测定其有关质量指标．通过筛选的优化处方为：香菇多糖50mg,赋形剂L-精氨酸300mg和甘露醇250mg,加水量为75mL,溶液PH值为7．0-7．5;制备的冻干粉针剂质量优良、综合评定其分值为5．处方合理,制备工艺可行,检验结果准确可靠．     

Nutritional and microbiological evaluations of chocolate-coated Chinese chestnut (Castanea mollissima) fruit for commercial use

In recent years, China has become an increasingly important and the largest chestnut producer in the world. This study aimed to evaluate the nutritional value and microbiological quality of the roasted freeze-dried Chinese chestnut (Castanea mollissima) (RFDC) coated with dark chocolate (DCC) and milk chocolate (MCC) for industrial use and commercial consumption.Chocolate coating significantly improved the nutritional value of chestnut. RFDC had high levels of starch (66.23%) and fibers (3.85%) while DCC and MCC contained significantly high amounts of sucrose, protein, fat and minerals. Furthermore, the protein content doubled in MCC rather than in DCC. This could be attributed to the different formulations in the two products. Milk powder and whey protein constituted the source of protein in MCC while cocoa powder added to MCC formulation constituted an additional source of minerals. The amino acid profile showed differences in amino acid composition related to the sample's protein content, indicating their good nutritional quality. The moisture contents in all RFDC, DCC and MCC were suitable for industrial processing. These results provide information about the additional nutrients of chocolate-coated chestnut and confirm that the product is an interesting nutritional food. The combination of freeze-drying and chocolate-coating generally results in greater reductions on microbiological loads, extending shelf life of harvested chestnut for commercial application. This is an alternative strategy to add value to chestnut, minimizing the significant losses in harvested fruits and providing a wider range of choices of new products to the consumer disposal.     

冷冻干燥法制备隐丹参酮纳米脂质体

目的：用大豆卵磷脂作为载体,以隐丹参酮作为模型药。制备隐丹参酮纳米脂质体。方法：用超声一匀浆一冷冻干燥法制备隐丹参酮纳米脂质体。采用透射电镜测试隐丹参酮脂质体的粒径,用激光粒度分布仪测试平均粒径及粒度分布。结果：冷冻干燥法制备隐丹参酮纳米脂质体的粒径20—80nm之间。随着大豆卵磷脂与隐丹参酮配比的减小,粒径逐渐减小,包封率逐渐减小。体外释药表现为零级动力学释药特征。结论：用超声一匀浆一冷冻干燥法制备隐丹参酮纳米脂质体的方法可行。     

冷冻干燥法制备多孔生物活性玻璃陶瓷

以纳米级45S5生物玻璃粉体为原料,采用冷冻干燥法,以丙三醇(甘油)、聚乙二醇为分散剂,制备多孔生物陶瓷材料。实验结果表明:通过冷冻铸造法制备的复合陶瓷呈薄层状结构,在950℃下烧结的材料能保持多孔形貌,但是孔隙分布不均匀,大多为2-10μm的微孔,由阿基米德排水法测得的孔隙率知道孔隙在60%以上,孔径内部连通性良好;1 050℃下生物玻璃粉体出现玻璃软化,冻干胚体经烧结出现塌陷,微孔消失,孔径的连通性较差,大多数孔隙为不连通的半开孔。高温烧结定向多孔结构陶瓷胚体,温度高于1 000℃生物玻璃发生软化难以保持材料的定向多孔结构。生物玻璃粉体烧结多孔陶瓷的温度为950℃。     

Need Assessment of Computer Science and Engineering Graduates

This case study considered the syllabus of the first and second year studies in computer science. The aim of the study was to reveal which topics covered in the syllabi were really needed during the following years of study or in working life. The program that was assessed in the study was a Masters program in computer science and engineering at a university of technology in Finland. The necessity of different subjects for the advanced studies (years 3?–?5) and for working life was assessed using four content analyses: (a) the course catalog of the institution where this study was carried out, (b) employment reports that were attached to the applications for internship credits, (c) masters theses, and (d) job advertisements in a newspaper. The results of the study imply that the necessity of physics for the advanced study and work was very low compared to the extent to which it was studied. On the other hand, the necessity for mathematics was moderate, and it had remained quite steady during the period 1989?–?2002. The most necessary computer science topic was programming. Also telecommunications and networking was needed often, whereas theoretical computer science was needed quite rarely.     

Student Use of Internet Study Rooms for Out-of-Class Group Study in Introductory Biology

This paper describes a pilot study in which undergraduates in an active introductory biology class (Biol 100) used online, virtual study rooms to study together outside of class in small groups. The study was conducted (a) to determine whether students who had access to Internet study rooms would make use of them for out-of-class group study, and (b) to find out how students perceived their online group study experience in comparison with face-to-face group study. Self-reported data were obtained at the time that multiple-choice exams were administered in the large class of Biology 100. The survey was completed by 90 of the students who had signed up for online study rooms. The results indicated that 47 students used their online study rooms to study for the final exam together with other members of their in-class teams. More than half of the students who provided written comments were positive about their online experience. Even those who strongly preferred face-to-face meetings expressed willingness to use online study rooms in a pinch.     

Effects of role division, interaction, and shared mental model on team performance in project-based learning environment

The purpose of this study was to investigate the cognitive mechanism of project-based learning teams of college students on the basis of the Shared Mental Model (SMM) theory. The study participants were 237 female college students in Korea organized into 51 project teams. To test the study hypotheses, a structural equation modeling was employed. The major study findings are as follows: (1) As hypothesized, member interaction was a strong predictor both for team-related and for task-related SMM. (2) The level of the team’s division of labor reduced the member interactions. (3) Team-related and task-related SMMs were positively associated with team performance. The theoretical and practical implications based on these results are discussed.     

Patterns of integration,commitment, and student characteristics and retention among younger and older students

The primary purpose of this study was to explore the differential persistence impact of the components of the Tinto model, preentry characteristics, initial goals and commitments, integration, subsequent goals and commitments, and external commitments, to the process of younger and older student persistence. The sample (N=449) included first-time students enrolled full- or part-time at a large, urban community college. The study design was longitudinal with questionnaire data gathered at the beginning and end of the spring 1989 semester. Persistence was measured from the spring to the following fall semester. Discriminant function analysis was used to study multivariate differences between short-term persisters and nonpersisters. Younger (17 to 24 years) and older (25+ years) student data were analyzed separately. Findings indicated (1) integration was more important to the persistence of younger students than it was for the older cohort; (2) self-assessed study skills were the most important discriminator for older students; (3) student perceptions of cognitive and personal development were important to persistence in both groups; and (4) goal commitment was important to the persistence of both age groups.     

Prenatal diagnosis of congenital fetal heart abnormalities and clinical analysis

INTRODUCTION Congenital heart disease (CHD) is the most common congenital disorder resulting in significant prenatal and postnatal morbidity and mortality (Gil- lum, 1994; Gembruch, 1997) and is believed to be a multifactorial disorder arising from the combined effect of genetic predisposition and environmental factors. Prenatal diagnosis of CHD is very important for both fetal prognosis and decreasing economic burden of family and society. It was demonstratedt t - l t recently that fe…     

Exploring the Use of Computer Simulation to Evaluate the Implementation of Problem-Solving Consultation

The purpose of this study was to examine how school psychologists implemented the problem-solving consultation process within a computer-simulated school environment. Four school psychologists were recruited to complete three simulated consultation cases. The school environment was computer generated and all of the teachers and target students (clients) were computer generated. A qualitative case study design coupled with interviews was used in this study. Three themes emerged from the data analysis including (a) behavioral approach to problem conceptualization, (b) individualized approach to intervention design, and (c) minimal attention to plan evaluation. Implications for problem-solving consultation training as well as use of computer simulation are discussed.     

Game addiction and academic achievement

The primary aim of this study was to investigate the correlation between game addiction and academic achievement. The secondary aim was to adapt a self-report instrument to measure game addiction. Three hundred and seventy high school students participated in this study. Data were collected via an online questionnaire that included a brief explanation of the aim of the study, demographical questions, game addiction scale (GAS) and the grade point average of the current year. The GAS had two forms: (i) 21-item and (ii) 7-item. Game addiction and academic achievement were negatively correlated but this correlation was not supported by regression and structural equation modelling analyses. The present study primarily suggests that there may be a negative correlation between game addiction and academic achievement; however, this correlation may be qualified as negligible. In addition, the two forms of the GAS were adapted for Turkish language with reliability and validity to measure computer and video game addiction in adolescents as promising instruments.     

Dose-response study of spinal hyperbaric ropivacaine for cesarean section

Background： Spinal hyperbaric ropivacaine may produce more predictable and reliable anesthesia than plain ropivacaine for cesarean section. The dose-response relation for spinal hyperbaric ropivacaine is undetermined. This double-blind, randomized, dose-response study determined the ED50 （50% effective dose） and ED95 （95% effective dose） of spinal hyperbaric ropivacaine for cesarean section anesthesia. Methods： Sixty parturients undergoing elective cesarean section delivery with use of combined spinal-epidural anesthesia were enrolled in this study. An epidural catheter was placed at the L1-L2 vertebral interspace then lumbar puncture was performed at the L3-L4 vertebral interspace, and parturients were randomized to receive spinal hyperbaric ropivacaine in doses of 10.5 mg, 12 mg, 13.5 mg, or 15 mg in equal volumes of 3 ml. Sensory levels （pinprick） were assessed every 2.5 min until a T7 level was achieved and motor changes were assessed by modified Bromage Score. A dose was considered effective if an upper sensory level to pin prick of T7 or above was achieved and no intraoperative epidural supplement was required. ED50 and ED95 were determined with use of a logistic regression model. Results： ED50 （95% confidence interval） of spinal hyperbaric ropivacaine was determined to be 10.37 （5.23-11.59） mg and ED95 （95% confidence interval） to be 15.39 （13.81-23.59） mg. The maximum sensory block levels and the duration of motor block and the rate of hypotension, but not onset of anesthesia, were significantly related to the ropivacaine dose. Conclusion： The ED50 and ED95 of spinal hyperbaric ropivacaine for cesarean delivery under the conditions of this study were 10.37 mg and 15.39 mg, respectively. Ropivacaine is suitable for spinal anesthesia in cesarean delivery.     

The development of responsibility in young children: A 25-year view

This study was designed to determine if parental perceptions of children's potential contribution to household work has changed over the past 25 years. Data for this study were collected in 1956 and in 1983. The 1956 sample consisted of 170 white mothers and 210 black mothers of elementary school-age children, and 19 child development specialists. The 1983 sample was made up of 126 mothers and 92 fathers of preschool and school-age children. The Children's Responsibility Scale was adapted from the early Walters, Stromberg, and Lonian (1957) instrument. Median ages were given for boys and girls on 62 household tasks. The results were consistent: parental perceptions have changed very little over time. The major differences were that parents in the 1983 sample estimated older ages for items relating to tasks involving safety. An instructional component was incorporated in the study to test whether preschool-age children (n = 23) were capable of accomplishing household tasks. The results of this component were positive.