Avaliação dos impactos ambientais de um processo industrial utilizando como matéria-prima policarbonatos virgem e reciclado / Evaluation of environmental impacts of an industrial process using virgin and recycled polycarbonate raw material

RESUMO Os impactos ambientais gerados por processos produtivos é um assunto em crescente evidência no mundo organizacional, e a análise comparativa de processos vem sendo utilizada pelas empresas para verificar os impactos ambientais e suas principais fontes de emissões. A análise dos impactos de um processo produtivo, com dois contextos distintos para a produção de hastes de óculos de policarbonato (PC), em uma indústria localizada no interior de São Paulo, foi realizada com a finalidade de comparar os impactos ambientais gerados. Para isso, foram definidos dois cenários: o 1 representa o processo de injeção que utiliza 100% de PC virgem como matéria-prima, enquanto o 2 usa apenas 20% de matéria-prima virgem, sendo o restante proveniente de resíduos de PC reciclados internamente. Dados quantitativos e qualitativos referentes aos cenários foram coletados e utilizados para identificar os impactos ambientais gerados com o auxílio da metodologia de avaliação do ciclo de vida (ACV). Com os resultados obtidos e a análise comparativa realizada, foi possível verificar os benefícios ambientais resultantes da reciclagem interna da matéria-prima. A redução dos impactos no cenário 2 em comparação com o 1 foi expressiva, principalmente, devido à diminuição da necessidade da produção de matéria-prima virgem. Em todas as categorias de impactos analisadas, ocorreram reduções - por exemplo, na categoria "mudanças climáticas", a redução foi superior a 70%.

ABSTRACT The environmental impacts generated by production processes is a subject that is increasingly evident in the organizational world and the comparative analysis of processes is an effective method used by companies to verify their environmental impacts and main emission sources. The analysis of environmental impacts for a process with two different scenarios to produce Polycarbonate (PC) glasses temples, in an industry located in the region of São Paulo, was performed in order to compare the environmental impacts generated by both scenarios. Thus, two scenarios were defined: scenario 1 represents the injection process that uses 100% of virgin PC as raw material; while scenario 2 uses only 20% of virgin raw material, the remainder PC waste being internally recycled. Quantitative and qualitative data related to the scenarios were collected and used to identify the impacts generated using the life cycle assessment (LCA) methodology. With the results obtained and the comparative analysis performed, it was possible to verify the environmental benefits of using the internal recycling of raw material. The impact reduction in scenario 2, compared to scenario 1, was significant, mainly due to the decrease of the need to produce virgin raw material. There were no reductions in all impact categories analyzed; for example, reduction was over 70% in the "climate change" category.

Effects of microporous membranes with different pore sizes on the filtration of tumor cells / 临床检验杂志

Objective To investigate the filtration roles of microporous membranes with different pore sizes in the tumor cells with different diameters,and effects on the filtered cells.Methods Three kinds of tumor cells with different cell diameters and same concentrations,including Jurkat,K562 and A549,were filtered by the polycarbonate microporous membranes with different pore sizes such as 1,3,5,8 and 10 μm,respectively,and their filtration rates were determined.The diameters of three kinds of tumor cells before and after filtration,and the fixed K562 cells with formaldehyde,were measured by an optical microscope.The activity of the filtered K562 cells were detected by the trypan blue staining.After the filtered K562 cells were re-cultured,their proliferation activity was analyzed by the growth curve.Results Jurkat,K562 and A549 cells couldn't pass the filter membrane with 1 μm of pore size.The filtration rates of three kinds of tumor cells passing the fliter membranes with 3 μm,5 μm,8 μm and 10 μm of pore sizes increased in turn.The survival rate of K562 cells filtered by 3 μm of pore size of membrane was 92.0％,and the proliferation acticity of re-cultured K562 cells was still strong.The filtration rate of the fixed K562 cells with formaldehyde was significantly decreased,and the average diameter of the filtered cells had no obvious change.Conclusion The living cells are able to pass the membranes with the pore sizes less than their diameters.The living cells passed the filter membranes may still maintain their growth and proliferation activity.However,the fixation of formaldehyde may significantly reduce the number of cells passed the membrane.

Study on modification and biocompatibility of coated medical polycarbonate / 国际生物医学工程杂志

Objective To prepare and evaluate the biocompatibility of polycarbonate coated with low molecular weight heparin (LMWH) and partial oxidation sodium alginate(OSA).Methods Coating material was prepared by means of chemical graft-modification and the feature of the material was determined with infrared spectrum and the stablity of the coating in fluid was examined.Biocompatibility was evaluated by contact angle and in-vitro tests including protein adhesion,platelet adhesion and caugulation.Results LMWH or OSA was tightly combined with polycarbonate.After being coated,the contact angle,albumin and fibrinogen adhering to materials were decrease (P＜0.05).The anticoagulant activity was notably promoted by coating.Compared with LMWH coated material,the contact angle,albumin and fibrinogen adhering were decreased significantly,but the improvement of anticaugulation was limited(P＜0.05).Conclusion Chemical graft-modification LMWH or OSA can be applied to polycarbonate.The biocompatibility of the coated materials was significantly promoted.

Isoflurane cracks the polycarbonate connector of extra-corporeal circuit: A case report / 대한마취과학회지

Cardiopulmonary bypass (CPB) is widely used for cardiac surgery by virtue of its proven safety over the course of its use during the past half century. Even though perfusion is safer, incidents still occur. During the repair of a ventricular-septal defect in an 11-month-old infant, we experienced a critical incident related to the potential hazardous effect of volatile anesthetics on the polycarbonate connector of extra-corporeal circuit. The damage to the polycarbonate connector had occurred after spillage of isoflurane during the filling of the vaporizer, causing it to crack and leak. The incident was managed by replacement of the cracked connector during a temporary circulatory arrest. The patient was hypothermic and the time off bypass was less than 1.5 min. There were no neurologic sequelae, the patient made an uneventful recovery. In conclusion, the spillage of volatile anesthetics can cause cracks in the polycarbonate connector of the extra-corporeal circuit, leading to potentially interruption of CPB.

Fracture strength of tie wings in a newly-developed polycarbonate bracket / 대한치과교정학회지

OBJECTIVE: With an increasing demand for esthetic orthodontic appliances, the interest in polycarbonate brackets has also increased. However, polycarbonate bracket wings are prone to fracture. The purpose of this study was to evaluate the clinical usefulness of a newly-developed polycarbonate bracket by measuring the fracture strength of bracket tie wings. METHODS: Alice (K.M. Daicom, Seoul, Korea) and Spirit MB (Ormco, Glendora, CA, USA) brackets were used as an experimental and control bracket respectively. Each bracket group was divided into halves. One half was untreated and the other half was treated with 2,000 times of thermocycling between 5 degrees C and 55 degrees C. The fracture strength of the wing was measured by a universal testing machine. RESULTS: Alice bracket wings showed significantly higher strength than Spirit MB bracket wings in both untreated and thermocycled bracket cases. CONCLUSION: Alice brackets may be used clinically in terms of the strength of bracket wings.

The Effect of Surface Treatment on Bond Strength of Polycarbonate Bracket / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to evaluate whether the bond strength of polycarbonate brackets can be increased through surface treatment. METHODS: One hundred polycarbonate brackets (Alice) were bonded to bovine incisors with light-cured adhesive. The bracket bases were treated with one of three methods; sandblasting, plastic conditioner application, and combined treatment with sandblasting and plastic conditioner. The brackets without any surface treatment served as the control. The shear bond strength was tested with a universal testing machine, and failure pattern was assessed with the adhesive remnant index. RESULTS: The shear bond strength in all experimental groups was higher than that of the control group (p < 0.001). The group treated with plastic conditioner after sandblasting showed statistically higher shear bond strength than the sandblasting only group (p < 0.05). The group treated with plastic conditioner after sandblasting showed higher shear bond strength than plastic conditioner only group, but the difference was not statistically significant. CONCLUSION: The above results suggest that the surface treatments of polycarbonate bracket is mandatory to improve bond strength, and the most effective method is an application of plastic conditioner after sandblasting.

Bisphenol A, an Endocrine Disruptive Chemical, is Released from Cellulosynthetic Dialyzer (Hemophan(R)) during Hemodialysis / 대한신장학회잡지

BACKGOUND: Bisphenol-A (2,2-bis (4-hydroxyphenyl)propane, BPA) is suspected to be an endocrine disruptor. BPA is a component of polycarbonate (PC), polysulfone (PS), and epoxy resins. PC is used as a material in the case header. Evaluation of BPA release from hemodialyzers may be very important, because BPA released from hemodialyzers is directly introduced into blood circulation. We examined the plasma levels of BPA before and after a hemodialysis session to evaluate the degree of BPA in patients with regular hemodialysis. METHODS: Ten patients undergoing regular hemodialysis were enrolled. We used cellulosynthetic dialyzer (Hemophan(R)-Alwall GFS Plus 2) and Bisphenol A concentration in plasma that had been taken before and after a hemodialysis session determined by gas chromatography-mass spectrometry (GC/MS) analysis. RESULTS: Plasma BPA levels before and after a hemodialysis session were 0.02+/-0.05 ng/mL and 0.16+/-0.15 ng/mL respectively. Plasma BPA levels after a hemodialysis session were significantly higher than those before hemodialysis. There were no significant correlations between plasma BPA level and several clinical parameters such as Kt/V, duration of hemodialysis, ultrafiltraion, blood flow, and age. CONCLUSION: Very small amounts of BPA were released from the cellulosynthetic hemodialyzer during a hemodialysis session. BPA doesn't seem to accumulate in the body of patients undergoing regular hemodialysis using cellulosynthetic hemodialyzer.

Improvement for New Blinking Emergency Location Transmitter / 医疗卫生装备

Objective To develop a more reliable blinking emergency location transmitter with longer time for aircrew in distress. Methods The new LED and new type of explosion-proof casing material (Polycarbonate) with new technologies are adopted. Results Environmental tests and performance tests were done on the new emergency location transmitter according to the environmental requirements of aeronautic products. Conclusion The new emergency location transmitter can meet the operation requirements for aircrew in distress.

A Study on the Bond Strength of Reline Resin to Pressure Injection Type Thermoplastic Denture Base Resin / 대한치과보철학회지

The purpose of this study was to evaluate the bond strength of reline resin to pressure injection type thermoplastic denture base resin.The denture base resins used in this study were Hipolycarbonate(High Dental Co.,Japan),Acetal dental(Pressingdental s.r.l.,Repubblica di San Marino)of thermoplastic resin and Acron MC(GC Dental Industrial Co.,Japan)of heatcured resin.The reline resins used were Lucitone 199(Dentsply international Inc.,USA),Tokuso rebase(Tokuyama Corp.,Japan),and Lightdon-U(Dreve-Dentamid-Gmbh,Germany).The reline resins are representative of heat-cured,self-cured,and light-cured resin respectively.Bond strength was examined by use of a three-point transverse flexural strength test. The results were as follows: 1.The bond strength of Lucitone 199 to Acron MC was the highest. 2.The bond strengths of Lucitone 199 and Tokuso rebase to Hi-polycarbonate resulted in a value of approximately one half that of Lucitone 199 to Acron MC,and there were no significant differences between these and the bond strength of Tokuso rebase to Acron MC(p<0.05). 3.The bond strengths of reline resins to Acetal dental were lower than those of reline resins to Hi-polycarbonate. 4.For all base resins Lightdon-U showed lower bond strength than the other reline resins.