XOS IS A FUNCTIONAL POLYSACCHARIDE it is recognized as a super prebiotics bifidogenic factor and a health food to balance the microecological environment in human intestinal tract.
Product Introduction: Xylo-Oligosaccharide 95% Powder Shandong Bailong Chuangyuan Bio-tec Co.,Ltd , https://www.Chinabailong.com
Xylooligosaccharides are functional polysaccharides composed of 2-7 xylose molecules combined with β-1,4 glycosidic bonds. Its bifidus factor function is 10-20 times that of other polymerized sugars. Compared with the commonly used soybean oligosaccharides, fructooligosaccharides, isomalt oligosaccharides, etc., xylo-oligosaccharides have unique advantages. It can selectively promote the proliferation activity of intestinal bifidobacteria.
Application:
Xylo ooligosaccharide is suitable to replace part of sucrose and be added to various beverages and foods, such as:
Medicines and health products: patients with gastrointestinal dysfunction, diabetes, hypertension, obesity, arteriosclerosis, dental caries
Dairy beverages: milk powder, liquid milk, yogurt, lactic acid bacteria drinks, carbonated drinks, etc.
Food category:table food baked goods, condiments, desserts, various cans, candy
Feed category:as a feed additive to replace antibiotics
Biological safety cabinet introduction
Some people may think that the biosafety cabinet is nothing more than an iron box with a fan and some HEPA filters; in fact, the biosafety cabinet is much more complicated. Similarly, maintaining the safety of a biosafety cabinet is much more complicated than "regular replacement of filters." The purpose of this paper is to solve the problem of the safety performance of safety cabinets, and to provide guidance for laboratory staff, management personnel and other relevant personnel involved in the safety and maintenance of safety cabinets.
filter
The filter is a key component in the biosafety cabinet, which acts to filter bacteria and dust particles to purify the gas that is blown into the safe cabinet and discharged. The filter used in the safety cabinet must have sufficient filtration efficiency, otherwise it will not protect against biological hazards. The filter material should be silicate fiberglass. At present, HEPA high-efficiency filters with a cut-off efficiency of 99.99% for 0.3μm dust particles and ULPA ultra-high efficiency filters with 99.9998% cut-off efficiency are commonly used in safety cabinets. The latter has better filtration efficiency, tighter structure and larger unit filtration area, providing the equivalent of ISO3 cleanliness for the work area.
Fan system
A fan system that meets the national standard of the safety cabinet shall have the following functions: automatic air volume compensation function, which can automatically compensate the air volume to keep the air flow rate constant when the filter load wind pressure drops to a certain range; the motor has thermal protection function, Stable operation at 1.15 times rated voltage. The centrifugal outer rotor fan, which has been widely recognized by the clean industry, does not need to add lubricating oil, and has the characteristics of compact structure, light weight, good balance, fast heat dissipation and 100% speed control, and has good stability. Sex and longer life.
An interlock alarm system is required for the B2 type II biosafety cabinet, built-in and external exhaust fans, which will be described in detail below.
Airflow control and the concept of "airflow safety performance zone"
Airflow control is the core technology of biosafety cabinets. As a qualified biosafety cabinet, in addition to the required airflow rate, the airflow also needs to achieve directionality, stability and uniformity to meet the requirements of biohazard testing.
The international biosafety cabinet standard has a basic airflow safety range. For example, the US NSF49 standard specifies that the secondary biosafety cabinet has a minimum inlet airflow of 0.5 m/s; the EU EN12469 specifies an inlet airflow minimum of 0.40 m/s. The airflow speed of the safety cabinet must be at a suitable value, neither too high nor too low. If the airflow speed is too high, it will easily cause turbulence, which will cause the test article to lose its protection; if it is too low, it will not be able to exert sufficient protection (the pollutants in the cabinet can easily escape from the work area). The optimal speed settings for different biosafety cabinets are different, and the optimal set speed allows the safety cabinet to provide maximum protection. Manufacturers should perform airflow tests on all models of safety cabinets they produce to determine the optimum airflow safety zone and airflow settings and provide them to the user for reference.
Control and alarm system
Entering the era of microcomputer control, the control system of the safety cabinet is used to monitor the operation values ​​of the biological safety cabinet, and timely detect any faults and misoperations, notify the user to take measures with sound and light alarms, and automatically take corresponding interlocking safety measures. The system has a temperature-compensated flow rate sensor that measures the true airflow rate, including the intake, downflow, and outer exhaust (B2); the LCD displays real-time airflow/flow. The system will give an audible and visual alarm for low airflow or unsafe front window height.
The third edition of the WHO Laboratory Biosafety Manual requires that “Before starting work and after completing work, the safety cabinet should be operated for at least 5 minutes to complete the 'purification' process, ie the time for the contaminated air to escape from the safety cabinet should be set aside. The biosafety cabinet needs to have a corresponding preheating and shutdown procedure, and the user can set the time according to the actual needs. The hardware fault intelligent diagnosis system can prompt fault information. Has an administrator password function to prevent unauthorized personnel from modifying parameters and illegal operations.
The "Safety Failure Control System" with a timer allows the electronic control hardware of the biosafety cabinet to fail without compromising its safety performance. In the event of a failure, the biosafety cabinet will automatically restart and set the parameters within a safe range. When all functions are regulated on the operator panel, parameters can also be set via an RS232 computer interface, update control software and fault analysis. The user's investment is protected: the control software for the SentinelTM control system can be downloaded and updated via the website.
The “Fan Time Timer†can be used to time the actual use time of the safety cabinet, which is convenient for monitoring the working time of the ULPA filter and facilitating timely replacement. The "UV Time Timer" is used to time the UV lamp's working time for easy replacement. A special "maintenance mode" can be used for maintenance purposes, which bypasses the parameters, control and locking functions set by the safety cabinet. All input and output parameters can be observed for fault analysis.
The safety cabinet interlock function includes the following points:
1. External flow alarm interlock system (B2 type): If the external exhaust flow is lower than the minimum alert level, or the descending airflow is higher than the highest alert level, the microcomputer control system will immediately sound and light alarm and close the downflow of the safety cabinet. The air blower and the external exhaust fan continue to operate to prevent danger to the operator due to the reduction of the intake air flow.
2, front window height alarm interlocking system: Once the safety cabinet front window deviates from the working height, in order to prevent danger to the operator, the system warns the user with sound and light (B2 type will also close the inner fan through the interlock system to ensure the intake air flow) Stable).
3, UV light interlock function: In order to prevent workers from being exposed to ultraviolet radiation, safety cabinets should have UV light interlocking function. The UV lamp can only be activated if the glass front window is completely closed; if the front window is accidentally raised during UV sterilization, the UV lamp will automatically turn off.
Clean engineering design concept
As a clean air purification equipment, the safety cabinet also condenses the concept of clean engineering. The clean engineering features integrated into the design of the biosafety cabinet include: the work surface and the working chamber cavity are integrally formed with 304 stainless steel, the edges are treated by circular arc, the surface is free of screws and the joint is easy to clean; the drain tank is also integrated. Molding design, with bottom drainage arc design; convex air intake grille and drain hole design to ensure no dead space in the working area; anti-bacterial coating on the surface of the body to prevent harmful bacteria; additional external row installed on the top of the safety cabinet The gas regulating plate can improve the stability of the gas flow.
Ergonomic design concept
Ergonomics is a new subject, which studies the relationship between the three elements of human, machine and environment in the "human-machine-environment" system, and provides the theory and method for solving the human efficiency and health problems in the system. . The application of ergonomics brings human factors to the design of biosafety cabinets. The size and structure of the safety cabinet design combines the human body shape, body posture, visual field, illumination noise adaptability, and brings ergonomics. Design features include: 10° tilt angle design of front window operation surface, use of handrails, humanized inclination of LCD control panel, installation position of power socket and gas-liquid valve, frameless front window design, etc.
Additional security design features
After decades of experience in using biosafety cabinets, the cabinet design of the safety cabinet has also been improved. In the modified A/B3 and B2 biosafety cabinets, the design of “negative pressure surrounding positive pressure†has been introduced, that is, all the positive pressure zones (contaminated areas) in the safety cabinet are enclosed in the negative pressure to prevent the cause. Leakage due to filter leakage, seal failure, etc.
Foreign safety cabinet manufacturers have adopted a more reliable “three-layer sidewall designâ€: the space between the inner first layer and the second layer is negative pressure, and the outer third layer can also protect. Even if one side of the side wall is broken, there is no danger of dirt leakage. Compared with the glass side window and double side wall design of similar products, this three-layer sidewall design has better safety.
As an additional safety consideration for front window design, some safety cabinet manufacturers have begun to use double-layer film safety explosion-proof glass. The safety glass is further filled with a layer of high-strength viscous PVB material between the double tempered glass. In the case of high impact of the glass, this layer of PVB material can firmly adhere to the broken glass to prevent the glass from cracking. On the one hand, it can prevent physical damage to the operator; on the other hand, it can maintain the reliability of the front window airflow. Sex, which protects the operator and the environment, and has excellent UV resistance.
Electrical safety testing and certification
The electrical system of the biosafety cabinet needs to meet one or more of the following international standards: International Electrotechnical Commission IEC61010-1, EU EN61010-1, US UL61010-1, Canadian CSAC22.2No.1010.1-92 and China National Electrical Equipment Safety Standard BG4793 .1. All safety cabinets are subject to electronic safety testing and a test report attached to the factory. The international safety certification standard of the biosafety cabinet ensures that your safety cabinet is safe and reliable. In addition to understanding the above related factors, the best and quickest way to identify the safety performance of the safety cabinet is to know whether the safety cabinet you purchased has obtained the following main International safety cabinet certification:
1, EN12469: 2000 (EU Biosafety Cabinet Uniform Standard)
2, NSF49: 2002 (US biosafety cabinet standard - secondary biological safety cabinet)
3, JISK3800: 2000 (Japan Biosafety Cabinet Standard)
4, SFDAYY0569-2005 (China National Food and Drug Administration Biological Safety Cabinet Standard)
While seeking the manufacturer's product certification, users should also pay attention to the following matters:
1. When a manufacturer claims that its own safety cabinet meets an international standard, it may require proof of it - an independent test report signed by a legal certification body;
2. Some standards may not be directly related to the safety performance of safety cabinets. For example, biosafety cabinet manufacturers claim to obtain ISO9001 quality certification, and ISO9001 does not test the safety cabinet performance of the above international safety cabinet standards;
3. The certification must be tested and promulgated by an independent and legal safety cabinet certification body.
In May 2000, the European Committee for Standardization (CEN) promulgated the European standard EN12469:2000 for biosafety cabinets, which officially replaced the standards of biosafety cabinets of EU member states such as German DIN12950, ​​British BS5726 and France NFX-44-201, and became the European Union. Uniform standards for biosafety cabinets in the area.
NSF49 has been around since the 1970s and is recognized as the most comprehensive standard in the field of biosafety cabinets. In 2002, ANSI/NSF49 officially received the official approval of the American National Standards Institute (ANSI), becoming the unified standard for US biosafety cabinets.
The Japan Biosafety Cabinet Standard JISK3800:2000, which was promulgated by the Japan Air Purification Association (JACA) in 1994, is based on the US NSF49 standard and has stricter requirements on microbial challenges.
China National Food and Drug Administration established and promulgated the biosafety cabinet standard YY0569-2005 in July 2005. This standard is based on the US standard NSF49:2002 and incorporates the item-by-item features of the European standard EN12469:2000, such as the KIDiscus rapid bio-challenge test and the requirements for airflow display and alarm systems. The YY0569-2005 standard was implemented on June 1, 2006 and became the mandatory standard for the Chinese medical and health industry. Source of information (Hangzhou Shenan Testing, )