Synthetic microfiber emissions from denim industrial washing processes: An overlooked microplastic source within the manufacturing process of blue jeans.

In recent years, domestic laundry has been recognized as a relevant source of microfiber (MF) pollution to aquatic environments. Nevertheless, the MF emissions from industrial washing processes in real world scenarios have not been quantified. The aim of this study was to quantify the MF emissions from 3 industrial washing processes (rinse wash, acid wash and enzymatic wash) commonly employed in the manufacturing process of blue jeans. The blue jeans were characterized by ATR-FT-IR, SEM and TGA to study the morphology, the polymer chemical identity and the proportion of synthetic and natural fibers, respectively. The MF emissions were quantified as the MF mass and number emitted per washed jean. All the industrial washing processes released a majority of synthetic MF. The enzymatic wash produced the highest amount of MF, with 1423 MF per gram of fabric (MF/g) equivalent to 381.7 MF grams per gram of fabric (MF g/g), followed by the acid wash with 253 MF/g equivalent to 142.7 MF g/g and lastly the rinse wash with 133 MF/g equivalent to 62.3 MF g/g. Statistically significant differences between the MF sizes for all washing processes were found when evaluating the emissions by MF/g, however, the previous trend was not found for MF g/g. Moreover, the total MF emissions of an industrial washing process of a pair of blue jeans during its manufacture process are up to 10.95 times higher than the reported domestic washing estimates performed by the consumer available in the published literature. We demonstrate that studying industrial washing procedures of textile garments will improve the accuracy of the current estimates of MF emissions available in published reports, which will ultimately aid in the development of regulations for MF emissions at an industrial level.

Porous Thermoformed Protein Bioblends as Degradable Absorbent Alternatives in Sanitary Materials.

Protein-based porous absorbent structures can be processed and assembled into configurations suitable for single-use, biodegradable sanitary materials. In this work, a formulation based on a mixture of proteins available as industrial coproducts is processed into continuous porous structures using extrusion and assembled using conventional thermal methods. The experimental design led to formulations solely based on zein-gluten protein bioblends that could be manufactured as liquid absorbent pellets, compressed pads, and/or porous films. The processing versatility is attributed to the synergistic effect of zein as a low viscosity thermoformable protein with gluten as a readily cross-linkable high molecular weight protein. The capillary-driven sorption, the biodegradability of the materials, and the possibility to assemble the products as multilayer components provide excellent performance indicators for their use as microplastic-free absorbents. This work shows the potential of biopolymers for manufacturing sustainable alternatives to current nonbiodegradable and highly polluting disposable items such as pads and diapers.

Burnout and stress among nurses in a university tertiary hospital.

This cross-sectional, analytical and correlational study investigated the existence of Burnout based on a sample of 149 nurses of a university tertiary hospital from October to December 2008 and correlate Burnout with stressors in the hospital work environment. The Maslach Burnout Inventory, the Nurses' Stress Inventory and a questionnaire to characterize the subjects were applied. The results indicated the presence of Burnout in 7.3% of nurses (quartile) and 10.22% (tercile), and also a correlation among the inventories' domains. Vulnerability to this type of illness among nurses was increased by stress experienced in the work environment.

Lattice Boltzmann simulation of swelling of an implant for microtia manufactured with IPN hydrogel.

The swelling characteristics of an implant for microtia treatment manufactured with IPN hydrogel was achieved using a three-dimensional lattice Boltzmann model. Dimensionless units of length and mass were employed. Comparisons between computational data and experimental values obtained by an adsorption isotherm test of a hydrogel implant immersed in Ringer's solution at a constant temperature of 310.15 K achieve coefficients of determination between 0.98782 and 0.99669. The results demonstrate that the thickness of the sample has a great impact on the time required to achieve thermodynamic equilibrium. The method presented here is suitable to simulate the swelling of hydrogels of arbitrary geometries.

Professional exhaustion, quality and intentions among family health nurses.

OBJECTIVE: to analyze how family health nurses assess quality of care; check if they have any intention of leaving their current job and nursing; estimate prevalence of professional exhaustion; and correlate these variables. METHOD: cross-sectional and correlational study with 198 nurses. The Maslach Burnout Inventory was applied, as it has questions for characterizing nurses, assessing perception on quality of care and of material and human resources, and verifying intention of leaving current work and nursing. RESULTS: most nurses assess quality of care as good, 28.0% present emotional exhaustion, there is intention of leaving current work and nursing. CONCLUSIONS: family health nurses experience professional exhaustion, which in turn presents correlation with decreased quality of care and increased intentions of leaving current work and nursing.

Physicomechanical characterization and biological evaluation of bulk-fill composite resin.

The aim of this study was to evaluate the cytotoxic effect, degree of conversion (% DC), Vickers hardness (VH), and surface morphology of composite resins. Eleven resins, nine bulk-fill resins, and two conventional resins were evaluated. Each material was sampled to evaluate DC (using FTIR), VH, cytotoxicity (using MTT and Neutral Red - NR test), surface morphology (using SEM and AFM), and organic filler (using EDS). All statistical tests were performed with SPSS and the level of significance was set at 0.05. MTT revealed that the materials presented low or no cytotoxic potential in relation to the control. Opus was the resin with the lowest cell viability at a 1:2 concentration at 72 h (32%) and at 7 days (43%), but that significantly increased when the NR test was applied at a 1:2 concentration after 7 days. Thickness and surface subjected to polymerization had no influence on DC, and differences were observed only between the materials. In the microhardness test, statistical differences were observed between the evaluated thicknesses. The bulk-fill resins analyzed in this study exhibited low and/or no cytotoxicity to L929 cells, except for Opus, which showed moderate cytotoxicity according to the MTT assay. When the NR test was used, results were not satisfactory for all composites, indicating the need for different methodologies to evaluate the properties of these materials. The assessed resins demonstrated acceptable physicomechanical properties.

Pilot-scale synthesis and rheological assessment of poly(methyl methacrylate) polymers: perspectives for medical application.

This work presents the rheological assessment of poly(methyl methacrylate) (PMMA) polymers synthesized in a dedicated pilot-scale plant. This material is to be used for the construction of scaffolds via Rapid Prototyping (RP). The polymers were prepared to match the physical and biological properties required for medical applications. Differential Scanning Calorimetry (DSC) and Size Exclusion Chromatography (SEC) measurements verified that the synthesized polymers were atactic, amorphous and linear in chains. Rheological properties such as viscosity, storage and loss modulus, beyond the loss factor, and creep and recovery were measured in a plate-plate sensor within the viscoelastic linear region. The results showed the relevant influence of the molecular weight on the viscosity and elasticity of the material, and how, as the molecular weight increases, the viscoelastic properties are getting closer to those of human bone. This article demonstrates that by using the implemented methodology it is possible to synthesize a polymer, with properties comparable to commercially-available PMMA.

Starch and chitosan oligosaccharides as interpenetrating phases in poly(N-isopropylacrylamide) injectable gels.

Thermosensitive interpenetrating gels were prepared by physically blending poly(N-isopropylacrylamide) (PNIPA) as the matrix and the following polysaccharides as interpenetrating phases: chitosan oligosaccharides (identified as QNAD and QNED) and soluble starch (STARCH). The molecular weight of the dispersed phase, the free water/bound water ratio and the thermosensitivity (transition temperature: LCST) of the gels were determined. It was found that these gels are pseudoplastic and that their viscosity depends on the molecular weight of the dispersed phase. LCST transition occurred around 35-37°C. The morphology of the porosity of the freeze-dried samples was studied by Scanning Electron Microscopy (SEM). An in vitro test of cell hemolysis on blood agar showed that these gels are noncytotoxic. According to the results obtained, these interpenetrating gels show characteristics of an injectable material, and have a transition LCST at body temperature, which reinforces their potential to be used in the surgical field and as scaffolds for tissue engineering.

[Lean production and psychosocial risks: the case of a multinational merger in a metallurgical company in Brazil]. / Lean production e riscos psicossociais: o caso de uma fusão multinacional de grupo metalmecânico no Brasil.

This study focused on the method known as "lean production" as a work-related psychosocial risk factor in a Brazilian multinational auto parts company after its merger with other multinational companies. The authors conducted a qualitative analysis of two time points: the first using on-site observation and key interviews with managers and workers during implementation of lean production in 1996; the second, 16 years later, comparing data from a document search in labor inspection records from the Ministry of Labor and Employment and legal proceedings initiated by the Office of the Public Prosecutor for Labor Affairs. The merger led to layoffs, replacements, and an increase in the workday. A class action suit was filed on grounds of aggravated working conditions. The new production model led to psychosocial risks that increased the need for workers' health precautions when changes in the production process introduced new and increased risks of physical and mental illnesses.

Functional electrospun poly (lactic acid) scaffolds for biomedical applications: experimental conditions, degradation and biocompatibility study.

The electrospinning technique is a method used to produce nano and microfibers using the influence of electrostatic forces. Porous three dimensional networks of continuous and interconnected fibers as scaffolds were obtained from a poly (lactic acid) solution. The concentration of the polymeric solution, 12.5% m/w, as well as the conditions of voltage (V = 11kV) and tip-metallic collector distance (H = 13cm) were established to develop these scaffolds through the electrospinning process. The characteristics of the scaffolds, such as fiber diameter, sintering and the biomimetics of the characteristics of a native extra cellular matrix were verified by Scanning Electron Microscopy (SEM). The orientation induced in the material as a consequence of the electrospinning forces was studied by Differential Scanning Calorimetry (DSC) and X-Ray Diffraction (XRD).The same techniques were used to study the hydrolytic degradation of samples in a ringer solution (pH = 7-7.4 at 37 degrees C) for 12 weeks and showed evidences of superficial degradation on the microfibers. The suitability of these scaffolds for tissue engineering was studied through the primary cell culture of chondrocytes, by observing adhesion and cellular proliferation developed during 14 days of assay.

Professional exhaustion, quality and intentions among family health nurses / Agotamiento profesional, calidad e intenciones entre enfermeros de salud de la familia / Esgotamento profissional, qualidade e intenções entre enfermeiros de saúde da família

ABSTRACT Objective: to analyze how family health nurses assess quality of care; check if they have any intention of leaving their current job and nursing; estimate prevalence of professional exhaustion; and correlate these variables. Method: cross-sectional and correlational study with 198 nurses. The Maslach Burnout Inventory was applied, as it has questions for characterizing nurses, assessing perception on quality of care and of material and human resources, and verifying intention of leaving current work and nursing. Results: most nurses assess quality of care as good, 28.0% present emotional exhaustion, there is intention of leaving current work and nursing. Conclusions: family health nurses experience professional exhaustion, which in turn presents correlation with decreased quality of care and increased intentions of leaving current work and nursing.

RESUMEN Objetivo: analizar como enfermeros de salud de la familia evalúan la calidad del cuidado; verificar si tienen intención de dejar el trabajo actual y la enfermería; estimar la prevalencia de agotamiento profesional y correlacionar variables. Método: estudio transversal y correlacional con 198 enfermeros. Se utilizó el Maslach Burnout Inventory, cuestiones para caracterizar a los enfermeros, para evaluar percepción sobre la calidad del cuidado y de recursos materiales y humanos, así como para verificar intenciones de dejar el trabajo actual y la enfermería. Resultados: la mayoría de los enfermeros evalúa la calidad del cuidado como buena, el 28,0% presenta agotamiento emocional, con intención de dejar el trabajo actual y la enfermería. Conclusión: enfermeros de salud de la familia experimentan agotamiento profesional que presenta correlación con disminución de la calidad del cuidado y con aumento de las intenciones de dejar el trabajo actual y la enfermería.

RESUMO Objetivo: analisar como enfermeiros de saúde da família avaliam qualidade do cuidado; verificar se têm intenção de deixar o trabalho atual e a enfermagem; estimar prevalência de esgotamento profissional e correlacionar variáveis. Método: estudo transversal e correlacional com 198 enfermeiros. Foi utilizado o Maslach Burnout Inventory, questões para caracterizar os enfermeiros, para avaliar percepção sobre a qualidade do cuidado e de recursos materiais e humanos e para verificar intenções de deixar o trabalho atual e a enfermagem. Resultados: a maioria dos enfermeiros avalia a qualidade do cuidado como boa, 28,0% apresenta exaustão emocional, há intenção de deixar o trabalho atual e a enfermagem. Conclusão: enfermeiros de saúde da família vivenciam esgotamento profissional que apresenta correlação com diminuição da qualidade do cuidado e com aumento das intenções de deixar o trabalho atual e a enfermagem.

Physicomechanical characterization and biological evaluation of bulk-fill composite resin

Abstract The aim of this study was to evaluate the cytotoxic effect, degree of conversion (% DC), Vickers hardness (VH), and surface morphology of composite resins. Eleven resins, nine bulk-fill resins, and two conventional resins were evaluated. Each material was sampled to evaluate DC (using FTIR), VH, cytotoxicity (using MTT and Neutral Red - NR test), surface morphology (using SEM and AFM), and organic filler (using EDS). All statistical tests were performed with SPSS and the level of significance was set at 0.05. MTT revealed that the materials presented low or no cytotoxic potential in relation to the control. Opus was the resin with the lowest cell viability at a 1:2 concentration at 72 h (32%) and at 7 days (43%), but that significantly increased when the NR test was applied at a 1:2 concentration after 7 days. Thickness and surface subjected to polymerization had no influence on DC, and differences were observed only between the materials. In the microhardness test, statistical differences were observed between the evaluated thicknesses. The bulk-fill resins analyzed in this study exhibited low and/or no cytotoxicity to L929 cells, except for Opus, which showed moderate cytotoxicity according to the MTT assay. When the NR test was used, results were not satisfactory for all composites, indicating the need for different methodologies to evaluate the properties of these materials. The assessed resins demonstrated acceptable physicomechanical properties.

Evaluation of the potential of novel PCL-PPDX biodegradable scaffolds as support materials for cartilage tissue engineering.

Cartilage is a specialized tissue represented by a group of particular cells (the chondrocytes) and an abundant extracellular matrix. Because of the reduced regenerative capacity of this tissue, cartilage injuries are often difficult to handle. Nowadays tissue engineering has emerged as a very promising discipline, and biodegradable polymeric scaffolds are widely used as tissue supports. In cartilage injuries, the use of autologous chondrocyte implantation from non-affected cartilage zones has emerged as a very interesting technique, where chondrocytes are expanded in order to obtain a greater number of cells. Nevertheless, it has been reported that chondrocytes in bidimensional cultures suffer a dedifferentiation process. The present study sought, in the first place, to standardize a novel protocol in order to obtain primary cultures of chondrocytes from newborn rabbit hyaline cartilage from the xiphoid process. Second, the potential of porous three-dimensional (3D) biodegradable polymeric matrices as support materials for chondrocytes was evaluated: a novel poly(ε-caprolactone)-poly(p-dioxanone) (PCL-PPDX) blend in a 90:10 w:w ratio and poly(ε-caprolactone) (PCL). After achieving the standardization, a typical round-shaped chondrocyte morphology and the expression of collagen type II and aggrecan, evaluated by RT-PCR, were observed. Second-passage chondrocytes adhered effectively to these scaffolds, although cell growth at 7 days in culture was significantly less in the PCL-PPDX blend. After 3 weeks of culture on PCL-PPDX or PCL, the cells expressed collagen type II. The present study demonstrates the potential, unknown until now, of PCL-PPDX blend scaffolds in the field of cartilage tissue engineering.

Lean production e riscos psicossociais: o caso de uma fusão multinacional de grupo metalmecânico no Brasil / Lean production and psychosocial risks: the case of a multinational merger in a metallurgical company in Brazil / Lean production y riesgos psicosociales: el caso de una fusión dentro un grupo metalmecánico en Brasil

Estudamos o método denominado lean production como um dos elementos associados com riscos psicossociais relacionados ao trabalho em empresa multinacional de autopeças após sua fusão com outras multinacionais. Analisamos qualitativamente dois momentos: o primeiro por meio de observação local e entrevistas-chave com gerentes e trabalhadores, quando da implantação do lean production em 1996; o seguinte, confrontando 16 anos mais tarde dados de pesquisa documental em registros de inspeção de condições de trabalho elaborado pelo Ministério do Trabalho e Emprego e procedimentos judiciais iniciados pelo Ministério Público do Trabalho. A fusão implicou demissões, substituições e aumentos da jornada de trabalho. Houve a abertura de Ação Civil Pública suscitada pela piora das condições de trabalho. O novo modelo produtivo trouxe riscos psicossociais que reforçaram a necessidade da precaução em saúde do trabalhador quando mudanças no processo produtivo introduziram novos e maiores riscos de doenças físicas e mentais.

This study focused on the method known as “lean production” as a work-related psychosocial risk factor in a Brazilian multinational auto parts company after its merger with other multinational companies. The authors conducted a qualitative analysis of two time points: the first using on-site observation and key interviews with managers and workers during implementation of lean production in 1996; the second, 16 years later, comparing data from a document search in labor inspection records from the Ministry of Labor and Employment and legal proceedings initiated by the Office of the Public Prosecutor for Labor Affairs. The merger led to layoffs, replacements, and an increase in the workday. A class action suit was filed on grounds of aggravated working conditions. The new production model led to psychosocial risks that increased the need for workers’ health precautions when changes in the production process introduced new and increased risks of physical and mental illnesses.

Estudiamos el método llamado lean production como uno de los elementos asociados con riesgos relacionados con el trabajo en una empresa multinacional de autopartes, después de su fusión con otras multinacionales. Analizamos cualitativamente dos momentos: el primero por observación local, y entrevistas clave con directores y trabajadores, cuando se produjo la implantación del lean production en 1996; el siguiente, 16 años más tarde, comparando datos de investigación documental en registros de inspección de las condiciones de trabajo hechas por el Ministerio del Trabajo y Empleo y también procedimientos judiciales iniciados por el Ministerio Público del Trabajo. La fusión implicó despidos, sustituciones y aumentos de las jornadas de trabajo. Se inició un procedimiento sancionador público, debido al empeoramiento de las condiciones de trabajo. El nuevo modelo productivo acarreó riesgos psicosociales que aumentaron la necesidad de prevención en salud del trabajador, cuando los cambios en el proceso productivo introducen nuevos y mayores riesgos de enfermedades físicas y mentales.

Evaluation of cell affinity on poly(L-lactide) and poly(epsilon-caprolactone) blends and on PLLA-b-PCL diblock copolymer surfaces.

An evaluation of cell proliferation and adhesion on biocompatible film supports was performed. A series of films were compression molded from commercially available poly (L-lactide), PLLA, and poly(epsilon-caprolactone), PCL, and from their melt mixed blends (PLLA/PCL blends). These were compared with compression molded films of PLLA-b-PCL model diblock copolymers. The samples were analyzed by differential scanning calorimetry (DSC), contact angle measurements, and scanning force microscopy (SFM). Cell adhesion and proliferation were performed with monkey derived fibroblasts (VERO) and with osteoblastic cells obtained either enzymatically or from explants cultures of Sprague-Dawley rat calvaria. Migration studies were performed with bone explants of the same origin. The results obtained indicate that although all materials tested were suitable for the support of cellular growth, a PLLA-b-PCL diblock copolymer sample with 93% PLLA was significantly more efficient. This sample exhibited a unique surface morphology with long range ordered domains (of the order of 2-3 mum) of edge-on PLLA lamellae that can promote "cell contact guidance." The influence of other factors such as chemical composition, degree of crystallinity, and surface roughness did not play a major role in determining cell preference toward a specific surface for the materials employed in this work.

Interfaces LER/saúde mental: a experiência de um centro de referência em saúde do trabalhador do estado de São Paulo / Repetitive strain injury and mental health: an experience of a workers health reference center in the state of São Paulo, Brazil

Este relato apresenta demandas que cada vez mais chegam aos Cerests desafiando as equipes multidisciplinares para o desenvolvimento de novas modalidades de abordagem diagnóstica e terapêutica. A experiência é de um Cerest do interior de São Paulo na última década. Construída a partir do relato de trabalhadores, visitas a locais de trabalho, discussão com representantes de empresas e atuação de equipe plurinstitucional de LER, ilustra situações de trabalho potencialmente adoecedoras, em especial do sistema musculoesquelético (LER/DORT).Trabalhadores de cinco empresas de quatro diferentes ramos relatam pressão para produção, sobrecarga física e competitividade, situações de humilhação ou constrangimento como forma de ajustá-los aos padrões da empresa, além da exposição pública e da ?punição pelo adoecimento? dos acometidos pelos agravos que retornam ao trabalho. Verifica-se que há ainda grande deficiência no reconhecimento das situações em que o trabalho contribui para o adoecimento mental. Os profissionais da área da Saúde do Trabalhador devem estar especialmente atentos para identificar os casos de sofrimento mental nos portadores de LER/DORT e notificá-los. Recomenda-se que as informações geradas sejam reunidas, analisadas e divulgadas, de modo que possam ser instrumento para sensibilização dos profissionais de saúde em geral e gerar formas de intervenção mais eficazes à proteção à saúde dos trabalhadores.

This report presents some arriving demands at CEREST (Reference Center for Workers Health) that have challenged its multidisciplinary team to develop new diagnostics and therapeutic approaches. The experience comes from a CEREST located in a inland city of the state of São Paulo, during the last decade, based on workers reports, visits to work places, discussion with representatives of various sectors, as well as on the activity of the local Repetitive Strain Injury (RSI) pluri-institutional team. It illustrates work situations generating diseases and injuries in five companies, especially in the musculoskeletal system (RSI). Workers reported pressure to achieve production goals, physical overload and competition, humiliation and coercion as ways to fit them into company standards. Returning--to-work employees with RSI suffered public exposure and were punished for their illness. The report demonstrates that mental illness related to work is not adequately acknowledged yet. Professionals involved with Workers Health must be especially alert to identify mental suffering in RSI carriers and notify it. The authors ecommend that information should be gathered, analyzed and publicized to become a tool to create awareness among health professionals in general, and produce new and effective ways of intervention to protect workers health.

Burnout and Stress Among Nurses in a University Tertiary Hospital / Burnout e estresse em enfermeiros de um hospital universitário de alta complexidade / Burnout y estrés en enfermeros de un hospital universitario de alta complejidad

This cross-sectional, analytical and correlational study investigated the existence of Burnout based on a sample of 149 nurses of a university tertiary hospital from October to December 2008 and correlate Burnout with stressors in the hospital work environment. The Maslach Burnout Inventory, the Nurses’ Stress Inventory and a questionnaire to characterize the subjects were applied. The results indicated the presence of Burnout in 7.3 percent of nurses (quartile) and 10.22 percent (tercile), and also a correlation among the inventories’ domains. Vulnerability to this type of illness among nurses was increased by stress experienced in the work environment.

Estudo transversal, analítico e correlacional que objetivou investigar a existência de Burnout em amostra de 149 enfermeiros de um hospital universitário de alta complexidade, no período de outubro a dezembro de 2008, correlacionando-o com estressores do ambiente de trabalho hospitalar. Foram aplicados o inventário de Burnout de Maslach, o inventário de estresse em enfermeiros e uma ficha de caracterização dos sujeitos. Os resultados indicaram a presença das três dimensões sugestivas de Burnout em 7,3 por cento dos enfermeiros (quartil) e 10,22 por cento (tercil), bem como a correlação entre domínios dos inventários. A vulnerabilidade para esse tipo de adoecimento em enfermeiros foi potencializada pela vivência de estresse no ambiente de trabalho.

Se trata de un estudio transversal, analítico y de correlación que tuvo por objetivo investigar la existencia de Burnout en una muestra de 149 enfermeros de un hospital universitario de alta complejidad, en el período de octubre a diciembre de 2008, correlacionándolo con factores de estrés del ambiente de trabajo hospitalario. Fueron aplicados el Inventario de Burnout de Maslach, el Inventario de Estrés en Enfermeros y una ficha de caracterización de los sujetos. Los resultados indicaron la presencia de las tres dimensiones indicativas de Burnout en 7,3 por ciento de los enfermeros (cuartil) y 10,22 por ciento (tercil), así como la correlación entre dominios de los inventarios. La vulnerabilidad para ese tipo de enfermedad, en enfermeros, fue potencializada por la existencia de factores de estrés en el ambiente de trabajo.

Influence of in vitro hydrolytic degradation on the morphology and crystallization behavior of poly(p-dioxanone).

We have studied the hydrolytic degradation of high molecular weight poly(p-dioxanone), PPDX, sutures. The samples were degraded either in distilled water or in a phosphate buffer at 37 degrees C, and the starting viscosity-average molecular weight was 130 kg/mol. The hydrolytic degradation of PPDX occurs in an approximate two stage process where the amorphous regions of the sample are attacked faster than the crystalline regions of the sample. The changes experienced by the samples as degradation proceeded were successfully monitored by viscosimetry, differential scanning calorimetry (DSC), weight loss, pH changes, and scanning electron microscopy (SEM). Polarized optical microscopy (POM) observations performed on PPDX films revealed that PPDX crystallizes in spherulites whose detailed morphology depends on the supercooling employed during isothermal crystallization. Changes in the spherulitic morphology as molecular weight is reduced are only pronounced when the molecular weight is equal or lower than 8 kg/mol. The dependence of lamellar thickness as a function of isothermal crystallization temperature was examined by atomic force microscopy (AFM) in thin films of PPDX together with melting point data obtained by DSC. Through the use of the Thomson-Gibbs equation, we obtained a value of 166 erg/cm2 for the fold surface free energy of PPDX. This value is in the same range as those obtained previously for similar linear polyesters. The lamellar thickness, as well as the melting point, was found to have a small decreasing dependence with the molecular weight of the samples.

Ocorrência de silicose pulmonar na regiäo de Campinas - SP / Occurrence of silicosis in the region of Campinas - SP

A ocorrência, prevalência ou incidência de pneumoconioses em nosso meio é pouco conhecida. Introdutoriamente, destacamos a organizaçäo dos serviços afeitos à saúde ocupacional nos países desenvolvidos e o assunto polêmico da exposiçäo ocupacional à sílica, silicose e câncer de pulmäo. Com o objetivo de contribuirmos para tanto, realizamos estudo descritivo cujos critérios básicos de admissäo foram: antecedentes de exposiçäo ocupacional à poeira com sílica e o radiograma do tórax. Dessa forma, analisamos prontuários de várias instituiçöes cujos critérios de avaliaçäo ocupacional radiológica e da funçäo pulmonar foram padronizados pela Área de Saúde Ocupacional da Unicamp. Detectamos 818 casos de silicose pulmonar, sendo 764 do sexo masculino e 54 do feminino, com média de idade mais ou memos DP de 50,8 mais ou menos 10 anos (mediana de 49 anos), com tempo médio de exposiçäo ocupacional de 20,9 mais ou menos 8 anos. Quanto ao tabagismo, 300 eram fumantes (24,8 mais ou menos 17 anos-maço), 142 näo fumavam e em 376 a informaçäo näo foi disponível. Quanto à queixa clínica de cansaço, 169, 147 e 44 o referiam respectivamente aos grandes, médios e pequenos esforços e 101 näo tinham queixas. Os radiogramas com profusäo 1/0, 1/1 e 1/2 foram 445; os 2/1, 2/1 e 2/3 foram 250 e os 3/3 foram 123, nas mais variadas combinaçöes da forma e tamanho. Encontramos 145 radiogramas com grandes opacidades, "A" 36, "B" 64 e "C" 45. A funçäo pulmonar, avaliada pela espirometria em 372 indivíduos, foi normal em 229 e as alteradas foram do tipo obstrutivo em 108, restritivo em 19 e misto em 16 deles. Detectamos 36 casos de óbito, sendo 12 por insuficiência respiratória e dois por neoplasia do pulmäo, entre outros. Detectamos também 46 deles com familiares portadores de silicose, sendo 34 com irmäos. Concluímos que a precariedade da nossa estruturaçäo para enfrentar esse problema merece inadiável envolvimento das entidades afins