共查询到20条相似文献,搜索用时 78 毫秒
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徐明礼 《上海生物医学工程》1987,(3)
FEP超纯实验室瓶由纯聚全氟乙丙烯(FEP)塑料制成,具有纯度高、耐高低温、耐酸碱腐蚀、耐有机溶剂、防粘、透明、不易破碎等特点,可代替昂贵的石英玻璃容器。它集石英制品和通用塑料制品之长而避其短,是目前世界上先进国家超纯试验室必备的一种化学分析器皿,主要用作低温试验、微量金属分析和存放超纯试剂,广泛用于地质、冶金、原子能、环保、电子、生物、医学、化学、化工等科研及生产部门。 相似文献
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取美洲斑潜蝇严重危害的植物叶片 (叶上最好以 3龄幼虫为主 ) ,带回室内 ,放入玻璃钟罩或其它密闭容器内 ,次日便可以收集到大量老熟幼虫。如果试材为蛹 ,可将盛有老熟幼虫的器皿放入黑暗处 ,约 3h后幼虫便可化蛹。如果试材为成虫 ,可将蛹埋入盛有湿润土壤 (约 1 5cm深 )的器皿内 ,用玻璃钟罩隔离 ,在 30℃条件下 ,大约 7d后便可得到大量的成虫。获得大量同龄美洲斑潜蝇的方法@段国琪$山西省农科院棉花研究所!运城044000
@张战备$山西省农科院棉花研究所!运城044000
@张丽萍$山西省农科院棉花研究所!运城044000… 相似文献
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在中学讲授肾小体与肾小管的构造时,只用褂图和黑板画进行演示,直观性不够强,所以学生往往得不到明确的印象。我们曾用玻璃制成肾小囊和肾小管形状(图1),制作过程简便,一般玻璃工厂都能代制;再以细小的红色塑料线代毛细血管,缠绕成球形为肾小球,锒进肾小囊内,并继续以网状塑料线缠于肾小管上(图2),同时在部分塑料线上,涂上蓝漆表示静脉,整个模型便制成。经过一段时期试用演示教学,由于是玻璃模型,能明显看到构造情况,学生易于了解,效果很好,特作介绍。 相似文献
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世界上每年用于塑料生产的石油和天然气有 2 .7亿t,生产出的塑料不能降解。而现在常用的以填埋、焚烧方式处理塑料垃圾的形式 ,造成了塑料垃圾不断在自然界中积累 ,焚烧产生的大量有毒气体以及温室气体 ,对人类的生存环境形成了愈来愈大的威胁。“白色污染”成为目前环保中又一个极为严峻的课题。科学工作者经过不懈的努力 ,找到一种利用生物技术生产新型绿色环保塑料的方法 ,采用这种方法生产的塑料 ,其原材料为可再生的能源——植物 ,节约了宝贵的天然矿产资源 ;通过生物降解的方式可把这种塑料进行完全降解 ,不污染环境 ,我们把它们称为… 相似文献
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羽然 《小哥白尼(野生动物画报)》2011,(8)
雷哥,是一只骨瘦如柴的宠物变色龙。他独自生活在一个只有鞋盒大小的玻璃箱里,每天的生活除了吃喝拉撒,就是和主人为他准备的玩具——一只塑料小鱼过家家。 相似文献
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Lynette M. Hogan Robb T. Beal Robert G. Hunt 《The International Journal of Life Cycle Assessment》1996,1(3):159-167
Threshold Inventory Interpretation Methodology (TIIM) is a methodology for Life Cycle Inventory Interpretation (impact assessment). TIIM is unique in that it incorporates the spatial dependency of environmental releases, includes pollutant thresholds, and simplifies pollution prevention decision-making processes for industrial systems. It is predicated upon using the best scientific information available today. TIIM is demonstrated here through a case study using the atmospheric emissions for three juice container systems (glass, plastic A, plastic B). The emissions reported are from a life cycle inventory. A comparison of the kilograms of each emission from the glass and plastic A systems favored plastic A; however, the comparison of glass and plastic B was inconclusive. Application of the TIIM to the glass and plastic B data yielded more conclusive results. Use of the TIIM life cycle inventory interpretation approach yields results that are more easily interpreted, scientifically based, and, in many instances, more conclusive than results from existing impact assessment approaches. 相似文献
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Alexander C. Hwang Paris H. Grey Katrina Cuddy David G. Oppenheimer 《Journal of visualized experiments : JoVE》2012,(60)
The evaluation of proteins using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis is a common technique used by biochemistry and molecular biology researchers1-4. For laboratories that perform daily analyses of proteins, the cost of commercially available polyacrylamide gels (˜$10/gel) can be considerable over time. To mitigate this cost, some researchers prepare their own polyacrylamide gels. Traditional methods of pouring these gels typically utilize specialized equipment and glass gel plates that can be expensive and preclude pouring many gels and storing them for future use. Furthermore, handling of glass plates during cleaning or gel pouring can result in accidental breakage creating a safety hazard, which may preclude their use in undergraduate laboratory classes. Our protocol demonstrates how to pour multiple protein gels simultaneously by recycling Invitrogen Nupage Novex minigel cassettes, and inexpensive materials purchased at a home improvement store. This economical and streamlined method includes a way to store the gels at 4°C for a few weeks. By re-using the plastic gel cassettes from commercially available gels, labs that run frequent protein gels can save significant costs and help the environment. In addition, plastic gel cassettes are extremely resistant to breakage, which makes them ideal for undergraduate laboratory classrooms. 相似文献
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T Ishibashi M Himeno N Imaizumi K Maejima S Nakano K Uchida J Yoshida M Nishio 《Nitric oxide》2000,4(5):516-525
Contamination of various types of laboratory wares with NO(x) (NO(-)(2) and NO(-)(3)) was assessed systematically and the effect of extensive washing as a countermeasure was evaluated. Mean NO(x) contamination arising from a model procedure for NO(x) determination in plasma was 0.93 microM (range, 0.35-1.49 microM). The major source of contamination included conical tubes (54.8%) and pipette tips used for transfer of solution (12.3-16.3%). Except for soft glassware, most NO(x) contamination could be washed out by pure water. Although NO(x) contamination in respective laboratory wares could be reduced below detection levels by extensive washing, summation of the contamination through the model procedure could not be completely abolished (but the effect of washing persisted at least 10 days). Heavy contamination was noted in glassware (especially soft glass) and ultrafiltration units, which was difficult to remove. Several types of vacuum blood sampling tubes contained various levels of NO(x). Our results indicated that a small but significant amount of contamination remained in laboratory ware even after extensive washing, and that it is advisable to avoid the use of glassware (soft glass), ultrafiltration units, and vacuum blood sampling tubes during the processing of clinical sampling for the measurement of NO(x). 相似文献
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A simplified method of embedding stained mammary spreads of small mammals in plastic (Selection) is presented. Two standard 50 × 75 × 1 mm. glass slides, separated by 2 narrow glass strips of similar thickness, are used to form the embedding chamber. The glands are stained in toto in alum-carmine, dehydrated, defatted, infiltrated with uncatalyzed plastic and embedded in catalyzed plastic. After baking and cooling, the glass chamber separates readily and provides a thin square slide of plastic suitable for low-power microscopic examination, projection, and filing. 相似文献
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Rapid-cycle PCR uses fast temperature transitions and minimal denaturation and annealing times of "0" s to complete 30 cycles in 10 to 30 min. The most popular platform amplifies samples in glass capillaries arranged around a carousel with circulating air for temperature control. Recently, plastic capillary replacements for glass capillaries became available. We compared the performance of plastic and glass capillaries for rapid-cycle PCR. Heat transfer into plastic capillaries was slowed by thicker walls, lower thermal conductivity, and a lower surface area-to-volume ratio than glass capillaries. Whereas the denaturation and annealing target temperatures were reached by samples in glass capillaries, samples in plastic capillaries fell short of these target temperatures by 6 degrees -7 degrees C. Rapid-cycle PCR was performed on two human genomic targets (APOE and ACVRL1) and one plasmid (pBR322) to amplify fragments of 225-300 bp in length with melting temperatures of 90.3 degrees -93.1 degrees C. Real-time amplification data, end-point melting curves, and end-point gel analysis revealed strong, specific amplification of samples in glass and complete amplification failure in plastic. Only the APOE target was successfully amplified by extending the denaturation and annealing times to 5 or 10 s. A 20 s holding period was necessary to reach target temperatures in plastic capillaries. 相似文献
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Life cycle assessment of two baby food packaging alternatives: glass jars vs. plastic pots 总被引:1,自引:0,他引:1
Sebastien Humbert Vincent Rossi Manuele Margni Olivier Jolliet Yves Loerincik 《The International Journal of Life Cycle Assessment》2009,14(2):95-106
Background, aim, and scope This paper compares the life cycle assessment (LCA) of two packaging alternatives used for baby food produced by Nestlé: plastic
pot and glass jar. The study considers the environmental impacts associated with packaging systems used to provide one baby
food meal in France, Spain, and Germany in 2007. In addition, alternate logistical scenarios are considered which are independent
of the two packaging options. The 200-g packaging size is selected as the basis for this study. Two other packaging sizes
are assessed in the sensitivity analysis. Because results are intended to be disclosed to the public, this study underwent
a critical review by an external panel of LCA experts.
Materials and methods The LCA is performed in accordance to the international standards ISO 14040 and ISO 14044. The packaging systems include the
packaging production, the product assembly, the preservation process, the distribution, and the packaging end-of-life. The
production of the content (before preservation process), as well as the use phase are not taken into account as they are considered
not to change when changing packaging. The inventory is based on data obtained from the baby food producer and the suppliers,
data from the scientific literature, and data from the ecoinvent database. Special care is taken to implement a system expansion
approach for end-of-life open and closed loop recycling and energy production (ISO 14044). A comprehensive impact assessment
is performed using two life cycle impact assessment methodologies: IMPACT 2002+ and CML 2001. An extensive uncertainty analysis
using Monte Carlo as well as an extensive sensitivity study are performed on the inventory and the reference flows, respectively.
Results When looking at the impacts due to preservation process and packaging (considering identical distribution distances), we observe
a small but significant environmental benefit of the plastic pot system over the glass jar system. Depending on the country,
the impact is reduced by 14% to 27% for primary energy, 28% to 31% for global warming, 31% to 34% for respiratory inorganics,
and 28% to 31% for terrestrial acidification/nutrification. The environmental benefit associated with the change in packaging
mainly results from (a) production of plastic pot (including its end-of-life; 43% to 51% of total benefit), (b) lighter weight
of packaging positively impacting transportation (20% to 35% of total benefit), and (c) new preservation process permitted
by the plastic system (23% to 34% of total benefit). The jar or pot (including cap or lid, cluster, stretch film, and label)
represents approximately half of the life cycle impacts, the logistics approximately one fourth, and the rest (especially
on-site energy, tray, and hood) one fourth.
Discussion The sensitivity analysis shows that assumptions made in the basic scenarios are rather conservative for plastic pots and that
the conclusions for the 200-g packaging size also apply to other packaging sizes. The uncertainty analysis performed on the
inventory for the German market situation shows that the plastic pot system has less impact than the glass jar system while
considering similar distribution distances with a confidence level above 97% for most impact categories. There is opportunity
for further improvement independent of the type of packaging used, such as by reducing distribution distances while still
optimizing lot size. The validity of the main conclusions presented in this study is confirmed by results of both impact assessment
methodologies IMPACT 2002+ and CML 2001.
Conclusions For identical transportation distances, the plastic pot system shows a small but significant reduction in environmental burden
compared to the glass jar system.
Recommendations and perspectives As food distribution plays an important role in the overall life cycle burdens and may vary between scenarios, it is important
to avoid additional transportation of the packaged food in order to maintain or even improve the advantage of the plastic
pot system. The present study focuses on the comparison of packaging systems and directly related consequences. It is recommended
that further environmental optimization of the product also includes food manufacturing (before preservation process) and
the supply chain of raw materials. 相似文献
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The covalent attachment of organic films and of biological molecules to fused silica and glass substrates is important for many applications. For applications such as biosensor development, it is desired that the immobilised molecules be assembled in a uniform layer on the surface so as to provide for reproducibility and speed of surface interactions. For optimal derivatisation the surface must be appropriately cleaned to remove contamination, to create surface attachment sites such as hydroxyl groups, and to control surface roughness. The irregularity of the surface can be significant in defining the integrity and density of immobilised films. Numerous cleaning methods exist for fused silica and glass substrates and these include gas plasmas, and combinations of acids, bases and organic solvents that are allowed to react at varying temperatures. For many years, we have used a well established method based on a combination of washing with basic peroxide followed by acidic peroxide to clean and hydroxylate the surface of fused silica and glass substrates before oligonucleotide immobilisation. Atomic force microscopy (AFM) has been used to evaluate the effect of cleaning on surface roughness for various fused silica and glass samples. The results indicate that surface roughness remains substantial after use of this common cleaning routine, and can provide a surface area that is more than 10% but less than 30% larger than anticipated from geometric considerations of a planar surface. 相似文献
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Massip A Van der Zwalmen P Ectors F De Coster R D'Ieteren G Hanzen C 《Theriogenology》1979,12(2):79-84
Ninety four cow embryos recovered on day 7-8 after onset of oestrus were frozen by the "Two Step" freezing procedure: 49 in pyrex glass ampules and 45 in .25 ml French semen straws. The overall survival rate was 33.7% (36.2% for embryos frozen in glass ampules; 31.1% for embryos frozen in plastic straws). 45.2% of transferred embryos resulted in pregnancies (35.7% after freezing in glass ampules v.s 52.9% after freezing in plastic straws). 相似文献
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Neutrophil responses to lipopolysaccharide. Effect of adherence on triggering and priming of the respiratory burst. 总被引:4,自引:0,他引:4
We studied neutrophil responses to LPS using three methodologic refinements: Teflon bags or serum-coated glass tubes that did not directly trigger neutrophils, LPS-free cytochrome c to measure O2- release, and heat-inactivated serum to inhibit inactivation of LPS by neutrophils. Neutrophils incubated in uncoated glass or plastic tubes adhered to the glass and released O2-, but were not primed for enhanced release of O2- in response to triggering by FMLP. Triggering by the glass or plastic surface did not occur if the neutrophils were stirred to prevent adherence. Adherence to glass or plastic and O2- release were not affected by a mAb (IB4) directed against the beta-chain of the leukocyte adhesion family of surface glycoproteins (CD11/CD18). Neutrophils incubated in glass or plastic did not show enhanced expression of alkaline phosphatase on their surface. When neutrophils were incubated in serum-coated glass tubes or in Teflon bags, there was no O2- release. However, adherence, expression of alkaline phosphatase, and release of O2- were triggered by adding 1 ng/ml LPS plus 1% serum, but not by either LPS or serum alone. In the presence of LPS and serum, O2- release was much higher when the cells were unstirred (adherent) rather than stirred. However, both unstirred and stirred cells expressed a similar elevated level of alkaline phosphatase. LPS-triggered O2- release and adherence were inhibited by antibody IB4. In contrast, priming by LPS for enhanced FMLP-triggered O2- release was greater in stirred cells than in unstirred cells. The antibody enhanced priming of unstirred neutrophils. These results suggested that uncoated glass or plastic triggered O2- release without involvement of leukocyte adhesion glycoproteins. However, neutrophils incubated with LPS and serum expressed alkaline phosphatase and IB4-inhibitable adherence glycoproteins that allowed neutrophils to interact with serum-coated glass or Teflon to trigger O2- release. Priming by LPS for enhanced response to FMLP was suppressed in adherent neutrophils, and this suppression was partly released by IB4. Thus, triggering and priming were reciprocally regulated by neutrophil glycoproteins interacting with surfaces. 相似文献
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Charles L. Bowman 《Cell biochemistry and biophysics》1998,29(3):203-223
I used capillary rise methods to investigate the lumenal surface properties of quartz (fused silica, Amersil T-08), borosilicate
(Corning 7800), and high-lead glass (Corning 0010) capillaries commonly used to make patch pipets. I calculated the capillary
rise and contact angle for water and methanol from weight measurements. The capillary rise was compared with the theoretical
maximum value calculated by assuming each fluid perfectly wetted the lumenal surface of the glass (i.e., zero contact angle,
which reflects the absence of surface contamination). For borosilicate, high-lead, and quartz capillaries, the rise for water
was substantially less than the theoretical maximum rise. Exposure of the borosilicate, lead, and quartz capillaries to several
cleaning methods resulted in substantially better—but not perfect—agreement between the theoretical maximum rise and calculated
capillary rise. By contrast, the capillary rise for methanol was almost identical in untreated and cleaned capillaries, but
less than its theoretical maximum rise. The residual discrepancy between the observed and theoretical rise for water could
not be improved on by trying a variety of cleaning procedures, but some cleaning methods were superior to others. The water
solubility of the surface contaminants, deduced from the effectiveness of repeated rinsing, was different for each of the
three types of capillaries examined: Corning 7800>quartz>Corning 0010. A surface film was also detected in quartz tubing with
an internal filament. I conclude that these borosilicate, quartz, and high-lead glass capillaries have a film on the lumenal
surface, which can be removed using appropriate cleaning methods. The surface contaminants may be unique to each type of capillary
and may also be hydrophobic. Two simple methods are presented to quantitate the cleanliness of glass capillary tubing commonly
used to make pipets for studies of biological membranes. It is not known if the surface film is of importance in electrophysiological
studies of biological membranes. 相似文献