The Geometry Effect in a Pioneering Experimental Study on the Batch Crystallization of the CAM

Far from being equivalent to host the process, the vessels play an active role in the crystallization thanks to their differently shaped bottoms. It was clearly pointed out through a meticulous experimental research on the batch crystallization of CAM （citric acid monohydrate） carried out in the years 1997-1998 by the author at the historic laboratories of＂La Sapienza＂ University of Rome. Such pioneering M.Sc. thesis, supervised by Prof. Barbara Mazzarotta （Department of Chemical Engineering）, was already summarized in an informative essay but, since the crystallization operating conditions to optimize were illustrated ＂collectively＂, it seemed necessary a further paper expounding uniquely the geometry effect. Our aim is to use all the data, collected and simulated, in order to show why the round-bottomed crystallizer performed better than the conical-bottomed one with the CAM from aqueous solutions, and why we should discard the flat-bottomed crystallizers.     

Physical Workload in Different Body Postures,While Working Near to,or Below Ground Level

The physical load of different working postures during a light job at low working level was compared while varying the frequency of forward movement and working level. The postures compared were bending, kneeling, squatting and sitting on a low stool. Energy expenditure, heart rate and the increase in heart rate over a five minutos' period were used as parameters. The following conclusions can be drawn. Bending and kneeling require less energy and arc less strenuous, when one hand (arm) is used as a support to balance the trunk. At high forward movement frequencies (more than 4 metres per minute or 5 movements per minute) the bending posture without arm support is loss strenuous than squatting and sitting on a one-legged stool. At low movements frequencies the squatting posture is preferable. Heart rate and energy consumption were slightly higher than that when sitting, but performance and also the gradient of the heart rate were slightly more favourable. The working height, varied from ? 14 cm to + 16 cm in comparison with the floor level, influenced the workload less. A remarkable increase in the work load was observed in the bending position only when the working level was lower than the level of the feet. If work has to be carried out in the ground itself, then squatting appears to be the most favourable position.     

Applications of Thermal Mechanical Compression Tests in Food Powder Analysis

A new Thermal Mechanical Compression Test (TMCT) was applied for glass-rubber transition and melting analyses of food powders and crystals. The TMCT technique measures the phase change of a material based on mechanical changes during the transition. Whey, honey, and apple juice powders were analyzed for their glass-rubber transition temperatures. Sucrose and glucose monohydrate crystals were analyzed for their melting temperatures. The results were compared to the values obtained by conventional DSC and TMA techniques. The new TMCT technique provided the results that were very close to the conventional techniques. This technique can be an alternative to analyze glass-rubber transition of food, pharmaceutical, and chemical dry products.     

共振光散射法测定鱼中汞含量

采用微波消解对鱼进行前处理,根据Hg2+在乙酸-乙酸钠缓冲液中对1,10-菲啰啉和灿烂黄所产生的共振光散射具有显著增强作用,建立了共振光散射法测定痕量汞的新方法。考察实验影响因素,确定最佳测定条件为10 mL比色管中加入pH 5.7乙酸-乙酸钠缓冲液1.5 mL、1.0×10-4 mol/L 1,10-菲啰啉溶液1.0 mL和4.0×10-5 mol/L灿烂黄溶液0.8 mL,反应温度25 ℃,反应时间5 min。最大共振光散射峰位于451.6 nm,共振散射光强度增加值与Hg2+质量浓度在0~50 μg/L范围内线性关系良好,方法的检出限为0.54 μg/L。大量的共存离子不干扰测定,Cu2+和Fe3+的干扰可加入氟化钠-硫脲混合掩蔽剂消除。将该法用于测定鱼中汞含量,结果与冷原子吸收光谱法一致,相对标准偏差为1.38~2.19% (n=5),平均回收率为99.33~102.00%。该方法灵敏准确、简便快速、精密度高、选择性好,高效环保,适用于鱼中汞的测定。     

Use of dietary supplementation with β-guanidinopropionic acid to alter the muscle phosphagen system,postmortem metabolism,and pork quality

Rate and extent of postmortem metabolism control pork quality development. Our objective was to evaluate the role of the phosphagen system (phosphocreatine, PCr; and creatine, Cr) on metabolism and pork quality. Muscle PCr and Cr were manipulated by feeding pigs the creatine analogue, β-guanidinopropionic acid (β-GPA). In experiment 1, pigs received standard (control) diet or β-GPA supplemented (2%) diet (1 wk or 2 wk). Supplementation with β-GPA (2 wk) decreased total Cr (PCr + Cr; P = 0.02) and improved pork color (decreased reflectance, P = 0.003); however, β-GPA supplementation reduced growth performance (P = 0.007). To separate effects of phosphagen system and growth, a second experiment was conducted with control, pair-fed, and 2 wk β-GPA (1%) supplementation; pigs were also offered a control or β-GPA supplemented flavored beverage. Neither treatment influenced pork quality. Immediately postmortem, ATP/ADP was higher in control compared to pair-fed (P < 0.05); subsequently, ATP/ADP was similar among all groups. Loss of the phosphagen system may lead to adaptive changes that promote conservation of cellular ATP.     

Differences in Characteristics of Pellets Prepared by Different Pelletization Methods

Pellets are currently a very popular dosage form for oral application. They can be prepared by several pelletization techniques. Extrusion/spheronization, commonly used in the pharmaceutical industry, and modern agglomeration in a rotoprocessor were the methods chosen for pellet preparation in our study. Theophylline (in 10% to 65% concentration) was the model drug, lactose monohydrate was used as filler, microcrystalline cellulose Avicel® PH 101 was thespheronization enhancer, and the wetting agent was purified water. Both techniques led to the formation of pellets of appropriate shape and mechanical properties. Pellets of a higher density, hardness, lower friability, and slightly slower dissolution profiles were obtained by extrusion/spheronization. This method of pelletization also led to production of particles with narrower size distribution and bigger yield of pellets with the requested size.     

硫酸氢钠催化合成乙酸异丁酯

以冰醋酸和异丁醇为原料,在一水合硫酸氢钠的催化作用下合成乙酸异丁酯,探讨了酸醇物质的量比,反应时间及催化剂用量对酯化率的影响。实验结果表明:一水合硫酸氢钠具有较好的催化活性,酸醇物质的量比为1:2.5,反应时间为150min,催化剂用量为1.2g,酯化率达92.33%。     

Development of a Lyophilized Parenteral Pharmaceutical Formulation of the Investigational Polypeptide Marine Anticancer Agent Kahalalide F

Kahalalide F is a novel antitumor agent isolated from the marine mollusk Elysia rufescens; it has shown highly selective in vitro activity against androgen-independent prostate tumors. The purpose of this study was to develop a stable parenteral formulation of kahalalide F to be used in early clinical trials. Solubility and stability of kahalalide F were studied as a function of polysorbate 80 (0.1%-0.5% w/v) and citric acid monohydrate (5-15 mM) concentrations using an experimental design approach. Stabilities of kahalalide F lyophilized products containing crystalline (mannitol) or amorphous (sucrose) bulking agents were studied at +5°C and +30°C ±60% relative humidity (RH) in the dark. Lyophilized products were characterized by infrared (IR) spectroscopy and differential scanning calorimetry (DSC). Recovery studies after reconstitution of kahalalide F lyophilized product and further dilution in infusion fluid were carried out to select an optimal reconstitution vehicle. It was found that a combination of polysorbate 80 and citric acid monohydrate is necessary to solubilize kahalalide F. Lyophilized products were considerably less stable with increasing polysorbate 80 and citric acid monohydrate concentrations, with polysorbate 80 being the major effector. A combination of 0.1% w/v polysorbate 80 and 5 mM citric acid monohydrate was selected for further investigation. Lyophilized products containing sucrose as a bulking agent were more stable compared to the products containing mannitol. The glass transition temperature of the sucrose-based product was determined to be + 46°C. The amorphous state of the product was confirmed by IR analysis. A solution composed of Cremophor EL, ethanol, and water for injection (5%/5%/90% v/v/v CEW) kept kahalalide F in solution after reconstitution and further dilution with 0.9% w/v sodium chloride (normal saline) to 1.5 μg/m. A stable lyophilized formulation was presented containing 100 μg of kahalalide F, 100 mg sucrose, 2.1 mg citric acid monohydrate, and 2 mg polysorbate 80 to be reconstituted with a vehicle composed of 5%/5%/90% v/v/v CEW and to be diluted further using normal saline.     

利用粗镁生产精制一水硫酸镁的研究

根据MgSO_4-H_2O体系相图,提出了运城盐湖冬季大田结晶的粗硫酸镁生产精制—水硫酸镁的工艺流程,并对工艺条件进行了探讨和分析,最后指出该产品具有纯度高、呈中性、不含重金属杂质等优点。