一种灭菌供暖供湿干燥装置

目的是提供一种理想的微生物培养室使用的灭菌供暖供温干燥装置。该装置由炉体(5)和灭菌干燥系统,包括鼓风机(1)、吸气管(13)、进气管(2)、受热管(3)、出气管(4);供温系统,包括水锅(6)、水锅进气管(7)、出汽管(8)、控制阀(9);燃烧系统包括出烟筒(10)、灶门(11),4大部分组成。结构简单、实用。     

呼伦贝尔沙地45年来气候变化及其对生态环境的影响

采用数理统计和对比分析方法,对近45年呼伦贝尔沙地气象观测资料和草场沙化、退化面积、植被状况等资料进行了分析。结果表明:呼伦贝尔沙地总体气候暖干化趋势显著;气温逐年升高、降水量减少、蒸发量增加和极端气候事件增多,使流动沙地面积不断增加,植被盖度下降。卫星遥感监测和全国沙漠化普查结果进一步表明,呼伦贝尔沙地的沙漠化正在扩展,生态环境正在恶化。逐年减少的大风日数和沙尘暴日数有利于该地区生态的保护与建设。20世纪80年代以来,沙区各级政府加大了对沙化的治理力度,沙地局部植被恢复较快。     

Development of a bladder instillation of the indoloquinone anticancer agent EO-9 using tert-butyl alcohol as lyophilization vehicle

The purpose of this research was to develop a stable bladder instillation of EO-9 for the treatment of superficial bladder cancer. First, stability and dissolution studies were performed. Subsequently, the freeze-drying process was optimized by determination of the freeze-drying characteristics of the selected cosolvent/water system and differential scanning calorimetry analysis of the formulation solution. Furthermore, the influence of the freeze-drying process on crystallinity and morphology of the freeze-dried product was determined with x-ray diffraction analysis and scanning electron microscopy, respectively. Subsequently, a reconstitution solution was developed. This study revealed that tert-butyl alcohol (TBA) can be used to both dramatically improve the solubility and stability of EO-9 and to shorten the freeze-drying cycle by increasing the sublimation rate. During freeze drying, 3 TBA crystals were found: TBA hydrate-ice crystals, crystals of TBA hydrate, and a third crystal, probably composed of TBA hydrate crystals containing ≈90% to 95% TBA. Furthermore, it was shown that crystallization of TBA hydrate was inhibited in the presence of both sodium bicarbonate (NaHCO₃) and mannitol. Addition of an annealing step resulted in a minor increase in the crystallinity of the freeze-dried product and formation of the δ-polymorph of mannitol. A stable bladder instillation was obtained after reconstitution of the freeze-dried product (containing 8 mg of EO-9, 20 mg of NaHCO₃, and 50 mg of mannitol per vial) to 20 mL with a reconstitution solution composed of propylene glycol/water for injection (WfI)/NaHCO₃/sodium edetate 60%/40%/2%/0.02% vol/vol/wt/wt, followed by dilution with Wfl to a final volume of 40 mL. Published: August 3, 2007     

Dry flowable formulations of antagonistic Bacillus subtilis strain T429 by spray drying to control rice blast disease

Dry flowable formulations of Bacillus subtilis strain T429 with fungicidal activity against the rice blast fungus Magnaporthe grisea were synthesized by spray drying. Inert ingredients including wetting agents, dispersants, disintegrants, and adhesives that show good biocompatibility with B. subtilis T429 were obtained. The formulations were optimized by a four-factor and three-level orthogonal experiment. The optimal contents of the wetting agent AEO-5, dispersant NNO, disintegrant (NH₄)₂SO₄, and adhesive CMC-Na were 1%, 9%, 5%, and 1% respectively, the filler kaolinite supplemented to 100%. The mixture was suspended in the fermentation broth of T429 at a ratio of 20% (m/v). After being ground in a ball mill for 3 h, the suspension was spray-dried, and the dry flowable formulations were obtained. The formulation showed good physical characteristics, such as high dispersibility and viability. After 12 months of storage at room temperature, it revealed long shelf life and high viability. Field tests in rice crops illustrated that dry flowable formulations at 50 and 75 g/667 m² concentrations were as effective as a commercial fungicide in controlling rice blast, control efficiency up to 77.6% and 78.5%, respectively. No significant differences in disease control efficiency were observed between the formulations and the chemical pesticide tricyclazole (79.5%). Overall, a new shelf-stable and effective dry flowable formulation of the biocontrol agent B. subtilis T429 was obtained by spray drying to control rice blast.     

不同干燥方法对蝇蛆蛋白粉营养价值的影响

采用化学分析和动物实验的方法对冷冻干燥、微波干燥和低温干燥的蝇蛆粉进行了营养评价。结果表明,3种干燥方法不影响蝇蛆粉的粗蛋白和灰分含量,但微波干燥蝇蛆粉的脂肪含量显著降低;氨基酸分析显示,冷冻干燥蝇蛆粉的氨基酸总含量>微波干燥的蝇蛆粉>低温干燥的蝇蛆粉,而3种方法干燥的蝇蛆粉EAA/TAA均等于或大于41%,说明干燥所得的蝇蛆粉均属优质蛋白。另外,与FAO/WHO参考模式值相比,冷冻干燥蝇蛆粉的必需和半必需氨基酸总量明显高于FAO/WHO参考模式值,微波干燥的蝇蛆粉与FAO/WHO参考模式值相当,而低温干燥的蝇蛆粉中必需与半必需氨基酸含量显著低于FAO/WHO参考模式值,说明微波干燥及低温干燥会破坏蝇蛆中的某些必需或半必需氨基酸。动物实验结果表明,冷冻干燥的蝇蛆粉在动物体内被吸收利用的程度最高,其次是酪蛋白,再次是低温干燥的蝇蛆粉,而微波干燥的蝇蛆粉被动物吸收利用的程度最低。     

Cytoenzymological analysis of adenylyl cyclase activity and 3':5'-cAMP immunolocalization in chloroplasts of Nicotiana tabacum

In this study a combination of cytoenzymological and immunocytochemical techniques was used in order to demonstrate the presence of cyclic nucleotide metabolism in chloroplasts of higher plants. Catalytic cytochemistry was used to localize adenylyl cyclase activity by means of electron microscope investigation on Nicotiana tabacum cv. Petit Havana leaf fragments. Various immunocytochemical techniques were explored to visualize the presence of the second messenger adenosine 3':5'-cyclic monophosphate. Making use of adenylyl imidodiphosphate as a substrate, the enzyme activity was predominantly located at the intermembrane space of the chloroplast envelope. In order to provide further topographical information, intact, isolated chloroplasts were submitted to the same cytoenzymological procedure and revealed stromal adenylyl cyclase activity. Using high-pressure freezing as a physical fixative to obtain an instantaneous metabolic arrest the cellular vitrified water phase was sublimed under ultra-high vacuum by means of molecular distillation drying, avoiding recrystallization and hence redistribution of small highly diffusible molecules. This sequential combination preserved 3':5'-cAMP epitope retention in chloroplasts as was demonstrated by immunogold labelling. These results further substantiate in a unique way the growing evidence of the presence of an organelle-specific cAMP metabolism in higher plants. Furthermore the data presented support the status of chloroplasts as an excellent model to further investigate cAMP metabolism and to correlate it with a variety of physiological functions.     

New drying process for lactic bacteria based on their dehydration behavior in liquid medium

This study describes the different stages of optimization in an original drying process for lactic acid bacteria that allows the retrieval of dried samples of Lactobacillus plantarum with maximum viability. The process involves the addition of casein powder to bacterial pellets, followed by mixing and then air-drying in a fluidized bed dryer. The effects on bacterial viability of the a(w) of the casein powder and the kinetics of a(w) variation in the fluidized bed dryer are considered. These parameters were first studied in a water-glycerol solution and the results were then applied to the drying process. Data from the study in liquid medium were reliable in the fluidized drying stage, insofar as optimal viability was achieved for similar dehydration times (16-50 min in liquid medium, and 30 min in the fluidized bed dryer). However, when the powder was mixed rapidly with bacteria, the level of destruction differed from that observed in liquid medium. Viability was up to 70% when the a(w) of water-glycerol was 0.55, whereas it was only 2.1% when the a(w) of the casein-bacterial mix was 0.64. The predictive capacity of dehydration in liquid medium is discussed with regard to the permeability of cells to external solutes. The new process allowed 100% survival of L. plantarum after complete drying (final a(w) < 0.2). However, when used for the desiccation of L. bulgaricus, these parameters achieved a viability of less than 10%.     

Resistance and Resilience of Macroinvertebrate Assemblages to Drying and Flood in a Tallgrass Prairie Stream System

Intermittent streams are common worldwide, and the ability of invertebrates to recover from floods and drought is a key feature of communities from these highly disturbed ecosystems. The macroinvertebrate assemblages of Kings Creek in northeastern Kansas were sampled regularly from four intermittent and two perennial sites over 2 years (1995–1996) to investigate the response and recovery to seasonal drying and floods. A 9mo drying period reduced taxa richness and density to 14% and 3% of pre-drying assemblages, respectively, in 1995–1996, whereas a 2mo drying period reduced richness by half and density to 4% of pre-drying assemblages in 1996. Floods at intermittent sites reduced densities and richness by 95% and 50%, respectively. A >50 y-flood reduced macroinvertebrate richness by 97% and density by >99% at a downstream perennial site. Resistance and resilience of total macroinvertebrate density was typically greater to floods than to drying, whereas resilience of taxa richness did not differ between disturbance types. The time required for recovery to pre-flood conditions (richness and density) was half as long (27 vs. 76 day) for intermittent sites compared to perennial sites. Colonization of intermittent sites was a function of distance from upstream refugia. Floods were a more important disturbance on assemblages in a downstream reach as compared to upstream reaches. In contrast, upstream reaches were more likely to dry. Recovery following flood and drought was dominated by colonization as opposed to tolerance, thus resilience is more important than resistance in regulating macroinvertebrate communities in these streams, and relative position in the landscape affects disturbance type, intensity, and ability of communities to recover from disturbance.     

Evaluation of manometric temperature measurement (MTM), a process analytical technology tool in freeze drying, part III: Heat and mass transfer measurement

This article evaluates the procedures for determining the vial heat transfer coefficient and the extent of primary drying through manometric temperature measurement (MTM). The vial heat transfer coefficients (K_v) were calculated from the MTM-determined temperature and resistance and compared with K_v values determined by a gravimetric method. The differences between the MTM vial heat transfer coefficients and the gravimetric values are large at low shelf temperature but smaller when higher shelf temperatures were used. The differences also became smaller at higher chamber pressure and smaller when higher resistance materials were being freeze-dried. In all cases, using thermal shields greatly improved the accuracy of the MTM K_v measurement. With use of thermal shields, the thickness of the frozen layer calculated from MTM is in good agreement with values obtained gravimetrically. The heat transfer coefficient “error” is largely a direct result of the error in the dry layer resistance (ie, MTM-determined resistance is too low). This problem can be minimized if thermal shields are used for freeze-drying. With suitable use of thermal shields, accurate K_v values are obtained by MTM; thus allowing accurate calculations of heat and mass flow rates. The extent of primary drying can be monitored by real-time calculation of the amount of remaining ice using MTM data, thus providing a process analytical tool that greatly improves the freeze-drying process design and control.     

Vacuum foam drying for preservation of LaSota virus: Effect of additives

The purpose of this research was to apply vacuum foam drying (VFD) for processing of LaSota virus and to screen formulation additives for its stability. The aqueous dispersion of harvest containing sucrose or trehalose in combination with additive (monosaccharides, polymers, N-Z-amine) was prepared. The diluted dispersions in vials were vacuum concentrated, foamed to form a continuous structure, and vacuum dried. The products were evaluated for foam characteristics, residual moisture, virus titer, x-ray diffraction pattern, and stability profile. The foamability increased with solid content in solutions. The foamability of sucrose was enhanced with incorporation of N-Z-amine (10% and 15% wt/vol) and polyvinyl pyrrolidone (PVP K30, 3% wt/vol). The fructose- or galactose-containing mixtures were deposited irregularly on the vial surface. The virus titer increased with disaccharides in the formulation. Sucrose provided better protection than trehalose. Unlike lyophilization, N-Z-amine with sucrose protected the virus from Millard’s Browning. Amino acids do not have a catalytic effect on hydrolysis of sucrose during VFD. Monosaccharides were ineffective. A synergistic effect of PVP K30 or polyethylene glycol 6000 (3% wt/vol) with N-Z-amine provided the maximum virus titer (6.97 and 7.15, respectively). This formulation retained the desired virus potency at 5°, 25°, and 40°C. The diffraction pattern revealed that a threshold concentration of N-Z-amine was required for inhibiting crystallization of sucrose during VFD. VFD was successfully applied to produce a solid LaSota formulation. The products were amorphous and did not devitrify on storage. Published: July 21, 2006