Effectiveness in Sterilization of Objects Produced by 3D Printing with Polylactic Acid Material: Comparison Between Autoclave and Ethylene Oxide Methods / Eficácia na esterilização de objetos produzidos pela impressão 3D com material ácido polilático: Comparação entre os métodos autoclave e óxido de etileno

Abstract Objective Due to the popularity of 3D technology, surgeons can create specific surgical guides and sterilize them in their institutions. The aim of the present study is to compare the efficacy of the autoclave and ethylene oxide (EO) sterilization methods for objects produced by 3D printing with polylactic acid (PLA) material. Methods Forty cubic-shaped objects were printed with PLA material. Twenty were solid and 20 were hollow (printed with little internal filling). Twenty objects (10 solid and 10 hollow) were sterilized in autoclave, forming Group 1. The others (10 solid and 10 hollow) were sterilized in EO, composing Group 2. After sterilization, they were stored and referred to culture. Hollow objects of both groups were broken during sowing, communicating the dead space with the culture medium. The results obtained were statistically analyzed (Fisher exact test and residue analysis). Results In group 1 (autoclave), there was bacterial growth in 50% of solid objects and in 30% of hollow objects. In group 2 (EO), growth occurred in 20% of hollow objects, with no bacterial growth in solid objects (100% of negative samples). The bacteria isolated in the positive cases was non-coagulase-producing Staphylococcus Gram positive. Conclusions Sterilization by both autoclave and EO was not effective for hollow printed objects. Solid objects sterilized by autoclave did not demonstrate 100% of negative samples and were not safe in the present assay. Complete absence of contamination occurred only with solid objects sterilized by EO, which is the combination recommended by the authors.

Resumo Objetivo Devido à popularidade da tecnologia 3D, cirurgiões podem criar guias cirúrgicos específicos e esterilizá-los nas suas instituições. O objetivo do presente estudo é comparar a eficácia dos métodos de esterilização por autoclave e óxido de etileno (OE) de objetos produzidos pela impressão 3D com material ácido polilático (PLA, na sigla em inglês). Métodos Quarenta objetos em formato cúbico foram impressos com material de PLA. Vinte eram sólidos e 20 eram ocos (impressos com pouco enchimento interno). Vinte objetos (10 sólidos e 10 ocos) foram esterilizados em autoclave, formando o Grupo 1. Os demais (10 sólidos e 10 ocos) foram esterilizados em OE, compondo o Grupo 2. Após a esterilização, os objetos foram armazenados e encaminhados para cultura. Objetos ocos de ambos os grupos foram quebrados durante a semeadura, comunicando o espaço morto com o meio de cultura. Os resultados obtidos foram analisados estatisticamente (teste exato de Fisher e análise de resíduo). Resultados No grupo 1 (autoclave) houve crescimento bacteriano em 50% dos objetos sólidos e em 30% dos objetos ocos. No grupo 2 (OE) o crescimento ocorreu em 20% dos objetos ocos, com ausência de crescimento bacteriano nos objetos sólidos (100% de amostras negativas). A bactéria isolada nos casos positivos foi Staphylococcus Gram positivo não produtor de coagulase. Conclusões A esterilização tanto em autoclave quanto pelo OE não foi eficaz para objetos impressos no formato oco. Objetos sólidos esterilizados em autoclave não demonstraram 100% de amostras negativas, não sendo seguro no presente ensaio. Ausência completa de contaminação ocorreu apenas com objetos sólidos esterilizados pelo OE, sendo a combinação recomendada pelos autores.

Advances on the production of organic acids by yeast / 生物工程学报

Organic acids are organic compounds that can be synthesized using biological systems. They often contain one or more low molecular weight acidic groups, such as carboxyl group and sulphonic group. Organic acids are widely used in food, agriculture, medicine, bio-based materials industry and other fields. Yeast has unique advantages of biosafety, strong stress resistance, wide substrate spectrum, convenient genetic transformation, and mature large-scale culture technology. Therefore, it is appealing to produce organic acids by yeast. However, challenges such as low concentration, many by-products and low fermentation efficiency still exist. With the development of yeast metabolic engineering and synthetic biology technology, rapid progress has been made in this field recently. Here we summarize the progress of biosynthesis of 11 organic acids by yeast. These organic acids include bulk carboxylic acids and high-value organic acids that can be produced naturally or heterologously. Finally, future prospects in this field were proposed.

Recent progress in the biosynthesis of dicarboxylic acids, a monomer of biodegradable plastics / 生物工程学报

Plastics are one of the most important polymers with huge global demand. However, the downsides of this polymer are that it is difficult to degrade, which causes huge pollution. The environmental-friendly bio-degradable plastics therefore could be an alternative and eventually fulfill the ever-growing demand from every aspect of the society. One of the building blocks of bio-degradable plastics is dicarboxylic acids, which have excellent biodegradability and numerous industrial applications. More importantly, dicarboxylic acid can be biologically synthesized. Herein, this review discusses the recent advance on the biosynthesis routes and metabolic engineering strategies of some of the typical dicarboxylic acids, in hope that it will help to provide inspiration to further efforts on the biosynthesis of dicarboxylic acids.

The degradation of plastics and the production of polyhydroxyalkanoates (PHA) / 生物工程学报

In recent years, the petroleum-based plastic pollution problem has been causing global attention. The idea of "degradation and up-cycling of plastics" was proposed for solving the environmental pollution caused by non-degradable plastics. Following this idea, plastics would be firstly degraded and then reconstructed. Polyhydroxyalkanoates (PHA) can be produced from the degraded plastic monomers as a choice to recycle among various plastics. PHA, a family of biopolyesters synthesized by many microbes, have attracted great interest in industrial, agricultural and medical sectors due to its biodegradability, biocompatibility, thermoplasticity and carbon neutrality. Moreover, the regulations on PHA monomer compositions, processing technology, and modification methods may further improve the material properties, making PHA a promising alternative to traditional plastics. Furthermore, the application of the "next-generation industrial biotechnology (NGIB)" utilizing extremophiles for PHA production is expected to enhance the PHA market competitiveness, promoting this environmentally friendly bio-based material to partially replace petroleum-based products, and achieve sustainable development with carbon-neutrality. This review summarizes the basic material properties, plastic upcycling via PHA biosynthesis, processing and modification methods of PHA, and biosynthesis of novel PHA.

Isolation and identification of a polyester-polyurethane degrading bacterium Bacillus altitudinis YX8-1 / 生物工程学报

Although polyurethane (PUR) plastics play important roles in daily life, its wastes bring serious environmental pollutions. Biological (enzymatic) degradation is considered as an environmentally friendly and low-cost method for PUR waste recycling, in which the efficient PUR-degrading strains or enzymes are crucial. In this work, a polyester PUR-degrading strain YX8-1 was isolated from the surface of PUR waste collected from a landfill. Based on colony morphology and micromorphology observation, phylogenetic analysis of 16S rDNA and gyrA gene, as well as genome sequence comparison, strain YX8-1 was identified as Bacillus altitudinis. The results of high performance liquid chromatography (HPLC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) showed that strain YX8-1 was able to depolymerize self-synthesized polyester PUR oligomer (PBA-PU) to produce a monomeric compound 4, 4'-methylene diphenylamine. Furthermore, strain YX8-1 was able to degrade 32% of the commercialized polyester PUR sponges within 30 days. This study thus provides a strain capable of biodegradation of PUR waste, which may facilitate the mining of related degrading enzymes.

Advances in biodegradation of polyolefin plastics / 生物工程学报

Polyolefin plastics are a group of polymers with C-C backbone that have been widely used in various areas of daily life. Due to their stable chemical properties and poor biodegradability, polyolefin plastic waste continues to accumulate worldwide, causing serious environmental pollution and ecological crises. In recent years, biological degradation of polyolefin plastics has attracted considerable attention. The abundant microbial resources in the nature offer the possibility of biodegradation of polyolefin plastic waste, and microorganisms capable of degrading polyolefin have been reported. This review summarizes the research progress on the biodegradation microbial resources and the biodegradation mechanisms of polyolefin plastics, presents the current challenges in the biodegradation of polyolefin plastics, and provides an outlook on future research directions.

Synthesis, biodegradation and waste disposal of polylactic acid plastics: a review / 生物工程学报

With the escalation of plastic bans and restrictions, bio-based plastics, represented by polylactic acid (PLA), have become a major alternative to traditional plastics in the current market and are unanimously regarded as having potential for development. However, there are still several misconceptions about bio-based plastics, whose complete degradation requires specific composting conditions. Bio-based plastics might be slow to degrade when it is released into the natural environment. They might also be harmful to humans, biodiversity and ecosystem function as traditional petroleum-based plastics do. In recent years, with the increasing production capacity and market size of PLA plastics in China, there is an urgent need to investigate and further strengthen the management of the life cycle of PLA and other bio-based plastics. In particular, the in-situ biodegradability and recycling of hard-to-recycle bio-based plastics in the ecological environment should be focused. This review introduces the characteristics, synthesis and commercialization of PLA plastics, summarizes the current research progress of microbial and enzymatic degradation of PLA plastics, and discusses their biodegradation mechanisms. Moreover, two bio-disposal methods against PLA plastic waste, including microbial in-situ treatment and enzymatic closed-loop recycling, are proposed. At last, the prospects and trends for the development of PLA plastics are presented.

Advances in methods for detecting plastics biodegradation / 生物工程学报

The pollution caused by improper handling of plastics has become a global challenge. In addition to recycling plastics and using biodegradable plastics, an alternative solution is to seek efficient methods for degrading plastics. Among them, the methods of using biodegradable enzymes or microorganisms to treat plastics have attracted increasing attention because of its advantages of mild conditions and no secondary environmental pollution. Developing highly efficient depolymerizing microorganisms/enzymes is the core for plastics biodegradation. However, the current analysis and detection methods cannot meet the requirements for screening efficient plastics biodegraders. It is thus of great significance to develop rapid and accurate analysis methods for screening biodegraders and evaluating biodegradation efficiency. This review summarizes the recent application of various commonly used analytical techniques in plastics biodegradation, including high performance liquid chromatography, infrared spectroscopy, gel permeation chromatography, and determination of zone of clearance, with fluorescence analysis techniques highlighted. This review may facilitate standardizing the characterization and analysis of plastics biodegradation process and developing more efficient methods for screening plastics biodegraders.

Preface to the special issue: biotechnology of plastic waste degradation and valorization / 生物工程学报

Synthetic plastics have been widely used in various fields of the national economy and are the pillar industry. However, irregular production, plastic product use, and plastic waste piling have caused long-term accumulation in the environment, contributing considerably to the global solid waste stream and environmental plastic pollution, which has become a global problem to be solved. Biodegradation has recently emerged as a viable disposal method for a circular plastic economy and has become a thriving research area. In recent years, important breakthroughs have been made in the screening, isolation, and identification of plastic-degrading microorganisms/enzyme resources and their further engineering, which provide new ideas and solutions for treating microplastics in the environment and the closed-loop bio-recycling of waste plastics. On the other hand, the use of microorganisms (pure cultures or consortia) to further transform different plastic degradants into biodegradable plastics and other compounds with high added value is of great significance, promoting the development of a plastic recycling economy and reducing the carbon emission of plastics in their life cycle. We edited a Special Issue on the topic of "Biotechnology of Plastic Waste Degradation and Valorization", focusing on the researches progress in three aspects: Mining microbial and enzyme resources for plastic biodegradation, Design and engineering of plastic depolymerase, and biological high-value transformation of plastic degradants. In total, 16 papers have been collected in this issue including reviews, comments, and research articles, which provide reference and guidance for further development of plastic waste degradation and valorization biotechnology.

Will there be an improvement of ecosystems in the world post-pandemic?

Purpose/Background. Inconsiderate human activities have led to ecological imbalances, and pollution and degradation of our natural environment. However, for humans to continue to exist on Earth in the future and for sustainable development to occur, we must preserve our ecosystems. Methodology/Approach. This paper examines some ethical considerations that are important to human interaction with the environment, by identifying conditions that existed before the Covid-19 pandemic. Results/Findings. The world is currently challenged by global inequality and global climate change, both of which adversely affect our living environment and very sensitive ecological systems. The physical confinement and social distancing measures imposed by governments worldwide during the Covid-19 pandemic produced a reduction in human interactions and activities which had a positive impact on the ecological environments around the world. Discussion/Conclusions/Contributions. As governments release their citizens from the tight restrictions, and people return to their customary activities, we can expect a return to pollution of our environments. This will occur unless, during the period of 'lockdown', humans had become more aware of the harmful effects some of their activities were having on the ecosystem and had been motivated to minimize these activities.

Propósito/Contexto. Las actividades humanas desconsideradas han llevado a desequilibrios ecológicos y a la contaminación y degradación de nuestro entorno natural, sin embargo, para que los seres humanos sigan existiendo en la Tierra en el futuro y para que se produzca un desarrollo sostenible, debemos preservar nuestros ecosistemas. Metodología/Enfoque. Este documento examina algunas consideraciones éticas que son importantes para la interacción humana con el medio ambiente, al identificar las condiciones que existían antes de la pandemia de COVID-19. Resultados/Hallazgos. Actualmente, el mundo enfrenta el desafío de la desigualdad global y el cambio climático global, los cuales afectan negativamente nuestro entorno de vida y sistemas ecológicos muy sensibles. Las medidas de confinamiento físico y distanciamiento social impuestas por los gobiernos de todo el mundo durante la pandemia de COVID-19 produjeron una reducción en las interacciones y actividades humanas que tuvieron un impacto positivo en los entornos ecológicos de todo el mundo. Discusión/Conclusiones/Contribuciones. A medida que los gobiernos liberan a sus ciudadanos de las estrictas restricciones y las personas regresan a sus actividades habituales, podemos esperar un regreso a la contaminación de nuestro medioambiente. Esto ocurrirá a menos que, durante el periodo de "bloqueo", los humanos se hayan vuelto más conscientes de los efectos nocivos que algunas de sus actividades tenían en el ecosistema y se hayan motivado a minimizar estas actividades.

Finalidade/Contexto. Atividades humanas imprudentes levaram a desequilíbrios ecológicos, poluição e degradação do nosso ambiente natural. No entanto, para que os humanos continuem a existir na Terra no futuro e para que o desenvolvimento sustentável ocorra, devemos preservar nossos ecossistemas. Metodologia/Abordagem. Este artigo examina algumas considerações éticas que são importantes para a interação humana com o meio ambiente, identificando as condições que existiam antes da pandemia de Covid-19. Resultados/Descobertas. O mundo é atualmente desafiado pela desigualdade global e pelas mudanças climáticas globais, que afetam negativamente nosso ambiente de vida e sistemas ecológicos muito sensíveis. As medidas de confinamiento físico e distanciamento social impostas pelos governos em todo o mundo durante a pandemia de Covid-19 produziram uma redução nas interações e atividades humanas que tiveram um impacto positivo nos ambientes ecológicos em todo o mundo. Discussão/Conclusões/Contribuições. À medida que os governos liberam seus cidadãos das rígidas restrições e as pessoas retornam às suas atividades habituais, podemos esperar um retorno à poluição de nossos ambientes. Isso ocorrerá a menos que, durante o período de 'lockdown', os humanos tenham se tornado mais conscientes dos efeitos nocivos que algumas de suas atividades estavam causando no ecossistema e tenham sido motivados a minimizar essas atividades.

Impact of microplastics on children s health / 中国学校卫生

Abstract@#As a new type of pollutant, microplastics have attracted extensive attention. Children in a critical stage of growth and development are vulnerable to microplastics. Summarzing the relevant laws and regulations and the source of microplastics, the paper demonstrates the ways of microplastics entering human body, some toxic effects of microplastics found in recent experimental studies and their potential hazards to children s health are introduced in detail.

Advance in the degradation of biodegradable plastics in different environments / 生物工程学报

With the continuously increasing demands of plastic products in the current society, the challenge of disposing plastic waste is constantly increasing, leading to the urgent need of mitigating plastic pollution. As a consequence, much attention has been paid to biodegradable plastics due to their degradability in a bio-active environment under certain conditions. Biodegradable plastics herald vast development potentials and considerable market prospects. The degradation of numerous types of biodegradable plastics will be affected by many factors. A thorough understanding of degradation mechanisms as well as functional microbial strains and enzymes is the key to comprehensive utilization and efficient treatment and disposal of biodegradable plastics. The article summarized the types, properties, advantages and disadvantages, and main applications of common biodegradable plastics. The degradation mechanisms, functional microbial strains and enzymes, as well as the degradation degree and duration under different environmental conditions, were also summarized. This review may help better understand the degradation of biodegradable plastics wastes.

Estudo epidemiológico da associação entre fatores de risco e excisões incompletas no câncer de pele / An epidemiological study of the association between risk factors and skin cancer incomplete excisions

Introdução: A crescente incidência de câncer de pele leva a um alto número de procedimentos cirúrgicos em todo o mundo. O principal objetivo do tratamento cirúrgico do câncer de pele é sua excisão completa, preservando a função e o melhor resultado estético. A ressecção inicial incompleta pode resultar em recorrências e danos graves. O objetivo é analisar os fatores de risco para margens positivas no seguimento de lesões cutâneas removidas cirurgicamente, por um ano, no departamento de cirurgia plástica do Hospital Royal Perth. Métodos: Foi analisado um levantamento de amostras histopatológicas de 947 pacientes operados. Todos os pacientes com excisão incompleta confirmada (EI) foram submetidos a uma segunda cirurgia ou até mesmo a uma terceira vez. Resultados: No total, 947 lesões foram encontradas, 6,6% das cirurgias tiveram margens comprometidas, com distribuição histopatológica de 75% de carcinoma basocelular (CBC), 21,4% de carcinoma de células escamosas (CCE) e 3,6% de outras lesões. A relação da presença de margens cirúrgicas comprometidas entre o CCE, quando comparada ao CBC, leva a um risco relativo de 2,8 e um valor p de 0,041, sugerindo que o primeiro é um fator de risco para a presença de margens cirúrgicas comprometidas. Para o estadiamento, a necessidade de uma segunda abordagem cirúrgica esteve presente em 61,29% dos pacientes, 20,9% estavam em observação, 3,2% estavam ausentes do serviço, 8% foram diretamente à quimioterapia ou radioterapia e 6,4% remarcaram a cirurgia. Conclusão: O conhecimento dos fatores de risco para margens positivas é necessário para que o cirurgião entenda o prognóstico e o acompanhamento de cada paciente.

Introduction: The increasing incidence of skin cancer leads to a high number of surgical procedures worldwide. The surgical treatment of skin cancer's main objective is its complete excision, preserving the function and the best aesthetic result. Incomplete initial resection can result in recurrences and major damage. The objective is to analyze the risk factors for positive margins in the follow-up of cutaneous lesions surgically removed, for one year, in the plastic surgery department of the Royal Perth Hospital. Methods: A survey of histopathological samples from 947 operated patients was analyzed. All patients with confirmed incomplete excision (IE) underwent a second surgery or even a third time. Results: In total, 947 lesions were found, 6.6% of surgeries had compromised margins, with a histopathological distribution of 75% of basal cell carcinoma, 21.4% of squamous cell carcinoma, and 3.6% of other lesions. The relation of the presence of compromised surgical margins between the SCC, compared to BCC, leads to a relative risk of 2.8 and a p-value of 0.041, which suggests that the SCC is a risk factor for the presence of compromised surgical margins. For staging, the need for a second surgical approach was present in 61.29% of the patients, 20.9% were under observation, 3.2% were absent from the service, 8% went directly to chemotherapy or radiotherapy, and 6.4% rescheduled the surgery. Conclusion: Knowledge of risk factors for positive margins is necessary for the surgeon to understand the prognosis and monitoring of each patient.

Degradation of petroleum-based plastics by microbes and microbial consortia / 生物工程学报

Along with the increasingly serious environmental pollution, dealing with the "white pollution" issue, which is caused by the worldwide use of not readily-degradable or non-degradable synthetic plastics, has become a great challenge. It is an environmentally friendly strategy to degrade synthetic plastics using microorganisms that exist in nature or evolved under selection pressure. Based on the NSFC-EU International Cooperation and Exchanges Project "Bio Innovation of a Circular Economy for Plastics", this review summarized the screening of bacteria, fungi and microbial consortia capable of degrading synthetic plastics such as polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyurethane (PUR), and polyethylene terephthalate (PET). We also analyzed the role of various microorganisms played in the degradation of petroleum-based plastics. Moreover, we discussed the pros and cons of using microorganisms and enzymes for degradation of synthetic plastics.

MIXed plastics biodegradation and UPcycling using microbial communities: the NSFC-EU 2019 project MIX-UP to help achieve "carbon neutrality" / 生物工程学报

With the transformation and revolution of the global plastics recycling system, recycling and upcycling of mixed plastics waste not only reduces the carbon emissions of plastics during its life cycle, but also addresses its potential ecological and environmental hazards. This article summarizes an international cooperation project, "MIXed plastics biodegradation and UPcycling using microbial communities" (MIX-UP) which was funded by the National Natural Science Foundation of China and the European Union (NSFC-EU) in 2019. The consortium of MIX-UP consists of 14 partners from European Union and China. Focusing on the global issue of "plastics pollution", this Sino-European MIX-UP project took the mixed waste of petroleum-based plastics (PP, PE, PUR, PET and PS) and bio-based plastics (PLA and PHA) as starting materials for biotechnological conversion into value-added, sustainable biomaterials. MIX-UP has three subprojects: 1) identification of plastics biodegradation pathway and design & engineering of key degrading elements, 2) construction and functional regulation of microbial consortia/enzyme cocktails with high-efficiency for degradation of plastics mixtures, 3) strategy of design and utilization of plastics degradation products for production of high value materials. Through NSFC-EU complementary and cross-disciplinary cooperation, MIX-UP proposes the engineering of a new-to-nature biological route for upcycling, a low carbon and sustainable bio-treatment that is different from the traditional physico-chemical treatment, which will empower the recycling industry to a new dimension. The implementation of the project will not only help to promote innovation and development in the field of biotechnology in China, but also contribute to the achievement of China's carbon neutral goal.

Dual application of black soldier fly (Hermetia illucens): Protein-rich animal feed and biological extraction agent for polyhydroxybutyrate

Aims@#The primary aim of the present study is to evaluate the effect of rearing substrates on the nutritional content of black soldier fly larvae (BSFL) by incorporating Cupriavidus necator cells containing intracellular polyhydroxybutyrate (PHB) in BSFL diet to further increase the protein content and simultaneously to biologically extract the polymer by utilizing the digestive system of BSFL. The potential application of BSFL as a biological PHB extraction agent was determined.@*Methodology and results@#Two feeding strategies consists of a mixture of protein (P) to carbohydrate (C) with a ratio of P50:C50 food waste (control feeding) and feed with bacterial cells (modified feeding). A comparison on the proximate analysis between this research and two commercially available products were conducted. Feeding BSFL with P50:C50 food waste revealed the highest crude protein content of 81.3 ± 0.2%. Additional bacteria cells in the BSFL diet, however, showed a negligible decrease in crude protein content of 0.67% as compared to the control feeding. Howbeit, this results comparably higher in contrast to the commercial products, with increment of crude protein content by 12.1% and 40.8%, respectively.@*Conclusion, significance and impact of study@#Two desirable products were obtained from the feeding with cells: (1) high protein content of BSFL and (2) biologically extracted polymer. This is the first study to demonstrate the utilization of BSFL as a biological extraction agent to partially extract biopolymer and increase the protein content by feeding with cells.

Assessment of knowledge and practice on plastics among the professional course students of Annamalai University, Tamil Nadu

Background: The use of plastics made life easy in day to day life. However, the disposal of it remains a public health problem worldwide. Plastic waste are major cause of environment pollution becomes carcinogenic to human, birth defects, impaired immunity, endocrine disruption, development and reproductive effect. Raising the awareness of the different stake holders is suggested by United Nations Environment Programme. Assessing the knowledge and practice of the student community, especially of the professional courses, in this regard is considered as a vital one.Methods: A total of 563 students of professional courses were included in the study. Their knowledge in terms general aspects, ill effects, reuse and practice in terms of usage and disposal were assessed with a questionnaire.Results: 46% of the students found having good knowledge. Only 27.6% were found to have good practice. Though the students have good knowledge on ill effects of plastics, their practice in terms of disposal was less. Significant variations were observed among the students of different courses.Conclusions: Addressing the gap between knowledge and practice in terms of designing messages for proper disposal and avoiding usage of single use plastics at individual and collective level is required.

Safety Evaluation of Bee Venom Plastics with Transdermal Administration / 中国药房

OBJECTIVE： To investigate the acute toxicity， long-term toxicity， skin irritation and anaphylaxis of Bee venom （BV） plastics， and to evaluate its preclinical safety. METHODS： The acute toxicity of BV plastics to rats was investigated after administration of high-dose， medium-dose and low-dose （144， 96， 48 mg/kg） of BV plastics. The long-term toxicity of BV plastics was investigated by continuous administration of high-dose， medium-dose and low-dose （72， 48， 24 mg/kg） of BV plastics for 28 days. The irritation of intact and damaged skin in rabbits with 8 mg/kg BV plastics was investigated by using the self-control method of left and right homologous body. The skin anaphylaxis of guinea pig were investigated after sensitized with 15 mg/kg BV plastics on the left back （on 0， 7th， 14th day） and stimulated with 15 mg/kg BV plastics on the right back. RESULTS： During the acute toxicity experiment with BV plastic，the weight of rats and the changes of viscera were normal，and there was no relevant toxic reaction. Long-term toxicity test results showed that no significant pathological changes were observed at 24 h after the last administration； the spleen index  of rats in BV low-dose group， testicular index in middle-dose group and epididymis index in high-dose and middle-dose groups were significantly increased， while PT in plasma of rats in BV medium-dose and low-dose groups was significantly prolonged （P＜0.05）. There were no abnormal changes in organ appearance， other organ index， coagulation index and blood biochemical index. All above indexes became normal at the end of 2-week recovery period. Skin irritation test showed that BV plastics could cause slight erythema and obvious scab on the skin of rabbits which along with little irritation on intact or damaged skin. Skin anaphylaxis test showed that BV plastics produced mild erythema in the skin of guinea pigs， belonging to light allergy. CONCLUSIONS： No acute or long-term toxicity is observed after transdermal administration of BV plastics， which is safe and only causes mild irritation and irritability to skin， indicating there is good safety of the plastic under experiment doses.

Improvement Effects of Bee Venom Plastics on Experimental Cerebral Thrombosis in Rats / 中国药房

OBJECTIVE： To study the improvement effects of Bee venom（BV） plastics on experimental cerebral thrombosis in rats. METHODS： Totally 96 SD rats were randomly divided into sham operation group （normal saline）， model group （plastics blank matrix）， Nimodipine group （positive drug， 4.00 mg/kg） and BV plastics low-dose， medium-dose， high-dose groups （1.67， 3.33， 6.67 mg/kg）， with 16 rats in each group. Rats in sham operation group and Nimodipine group were given medicine intragastrically， while rats in model group and BV plastics groups were given medicine by transdermal smearing. After 5 days of continuous administration， the experimental cerebral thrombosis model was established by ligating the right external carotid artery and pterygomandibular artery， and injecting compound thrombus inducer into the internal carotid artery. The wet mass ratio of right brain to left brain was measured to investigate the degree of brain edema on the infarcted side. The content of Evans blue （EB） in the left and right hemispheres of rats was determined by ultraviolet spectrophotometry to investigate the cerebral vascular permeability. Blood rheology and coagulation function indicators of rats were measured. The pathological changes of brain tissue in rats were observed by HE staining， and the number of survival neuron cells was counted. RESULTS： Compared with the indexes of sham operation group， the cerebral thrombosis model was established successfully. Compared with model group， the area of blue staining in the right brain （infarcted side） of rats in BV plastics groups was significantly reduced， and the right brain/left brain wet mass ratio and the content of EB in the right brain tissue were significantly reduced （P＜0.05 or P＜0.01）. The whole blood viscosity and Casson viscosity of rats in BV plastics groups， and the plasma viscosity of rats in BV plastics medium-dose and high-dose groups decreased significantly （P＜0.01）. PT and APTT of rats were prolonged significantly in BV plastics medium-dose group （P＜0.01）. The pathological changes of brain tissue in rats in BV plastics groups were significantly alleviated. The arrangement of neuron cells was more orderly， the shape and structure of cells were clear， the nucleolus was clear， the membrane was intact， and the number of survival neuron cells was significantly increased （P＜0.01）. CONCLUSIONS： BV plastics can alleviate brain edema， inhibit cerebral vascular permeability， improve hemorheology and coagulation function indicators of rats after the formation of cerebral thrombosis， and alleviate nerve cell injury after ischemia.

Clinical application of new type individualized fixation device for radiotherapy of rectal cancer / 中国基层医药

Objective To explore the clinical effect of new type rectal cancer radiotherapy individualized fixation device in the radiotherapy of rectal cancer. Methods From June 2015 to December 2016,60 patients with rectal cancer who accepted the external irradiation in Zhejiang Tumor Hospital were divided into two groups by random number table method. A group(31 cases) received new type rectal cancer radiotherapy position fixation devices with thermoplastic film. B group(29 cases) received simple foam pad with thermoplastic film. Before each treatment,Cone beam CT(CBCT) scan was conducted. The applied CBCT image and the planned reconstruction image were compared in the direction of X(left and right),Y(upper and lower)and Z(front and rear) axis. The setup error was recorded, and the correlation between the two groups was analyzed. Results The average setup error of patients in A group in X (left and right),Y(upper and lower),Z(front and rear) axis were (1. 61 ± 0. 18)mm,(1. 82 ± 0. 13)mm,(1. 91 ± 0. 11)mm,respectively. The average setup error of patients in B group in X(left and right),Y(upper and lower),Z (front and rear) axis were (2. 22 ± 0. 13)mm,(2. 43 ± 0. 14)mm,(2. 36 ± 0. 13)mm,respectively. There were statistically significant differences between the two groups(t=14. 958,17. 501,11. 283,all P＜0. 001). Conclusion The new type of rectal cancer radiotherapy position fixing device is more comfortable than the simple foam pad,and the setting error is smaller than the simple foam pad.