Synthesis of ultra-high molecular weight homo- and copolymers via an ultrasonic emulsion process with a fast rate.

In the forefront of advanced materials, ultra-high molecular weight (UHMW) polymers, renowned for their outstanding mechanical properties, have found extensive applications across various domains. However, their production has encountered a significant challenge: the attainment of UHMW polymers with a low dispersity (Ɖ). Herein, we introduce the pioneering technique of ultrasound (US) initiated polymerization, which has garnered attention for its capability to successfully polymerize a multitude of monomers. This study showcases the synthesis of UHMW polymers with a comparatively low Ɖ ( ≤ 1.1) within a remarkably short duration ( ~ 15 min) through the amalgamation of emulsion polymerization and high-frequency ultrasound-initiated polymerization. Particularly noteworthy is the successful copolymerization of diverse monomers, surpassing the molecular weight and further narrowing the Ɖ compared to their respective homopolymers. Notably, this includes monomers like vinyl acetate, traditionally deemed unsuitable for controlled polymerization. The consistent production and uniform dispersion of radicals during ultrasonication have been identified as key factors facilitating the swift fabrication of UHMW polymers with exceptionally low Ɖ.

The Power of Automation in Polymer Chemistry: Precision Synthesis of Multiblock Copolymers with Block Sequence Control.

Machines can revolutionize the field of chemistry and material science, driving the development of new chemistries, increasing productivity, and facilitating reaction scale up. The incorporation of automated systems in the field of polymer chemistry has however proven challenging owing to the demanding reaction conditions, rendering the automation setup complex and costly. There is an imminent need for an automation platform which uses fast and simple polymerization protocols, while providing a high level of control on the structure of macromolecules via precision synthesis. This work combines an oxygen tolerant, room temperature polymerization method with a simple liquid handling robot to automatically prepare precise and high order multiblock copolymers with unprecedented livingness even after many chain extensions. The highest number of blocks synthesized in such a system is reported, demonstrating the capabilities of this automated platform for the rapid synthesis and complex polymer structure formation.

Reduced Ice Adhesion Using Amphiphilic Poly(Ionic Liquid)-Based Surfaces.

Ice build-up on solid surfaces causes significant economic losses for a range of industries. One solution to this problem is the development of coatings with low ice adhesion strength. Amphiphilic poly(ionic liquid) (PIL)-based surfaces have been recently reported for antifogging/antifrosting applications. However, they have possible anti-icing properties through lowering the ice adhesion strength that have yet to be reported. Herein, we designed well-defined triblock copolymers composed of a polydimethylsiloxane component coupled with PIL segments of poly([2 (methacryloyloxy)ethyl] trimethylammonium chloride) (PMETAC), which were subsequently UV-cured with an oligo(ethylene glycol) dimethacrylate (OEGDMA) cross-linker. The structure-property relationships of the resultant semi-interpenetrating polymer networks (SIPNs) were investigated by varying the counterion (i.e., trimethylammonium bis(trifluoromethanesulfonyl)imide (TFSI-)) and the content of the PIL segments and cross-linker. An ice adhesion strength as low as 13.3 ± 8.6 kPa was observed for the coating containing 12.5 wt % of PMETAC segment and 5 wt % of OEGDMA, which is one of the lowest values reported so far for the amphiphilic coatings. Characterization of the coatings in terms of surface features, wettability, and hydration states have enabled the elucidation of different deicing mechanisms. Self-lubrication due to the existence of nonfreezable bound water led to the obtained low ice adhesion strength. This work offers a new approach for the exploration of PIL-based icephobic coatings for practical applications.

Infant mortality in Brazil attributable to inborn errors of metabolism associated with sudden death: a time-series study (2002-2014).

BACKGROUND: The literature suggests that 0.9 to 6% of infants who die unexpectedly may have had a metabolic disorder. At least 43 different inborn errors of metabolism (IEMs) have been associated with sudden death (SUDI). To date, the frequency of IEM-associated SUDI has not been studied in Brazil. The present study sought to characterize infant mortality related to IEMs known to cause SUDI disaggregated by each of the regions of Brazil. METHODS: This was a descriptive, cross-sectional, population-based study of data obtained from the Brazilian Ministry of Health Mortality Information System (SIM). Death records were obtained for all infants (age < 1 year) who died in Brazil in 2002-2014 in whom the underlying cause of death was listed as ICD-10 codes E70 (Disorders of aromatic amino-acid metabolism), E71 (Disorders of branched-chain amino-acid metabolism and fatty-acid metabolism), E72 (Other disorders of amino-acid metabolism), or E74 (Other disorders of carbohydrate metabolism), which are known to be associated with SUDI. RESULTS: From 2002 to 2014, 199 deaths of infants aged < 1 year were recorded in the SIM with an underlying cause corresponding to one of the IEMs of interest. The prevalence of IEM-related deaths was 0.67 per 10,000 live births (0.58-0.77). Of these 199 deaths, 18 (9.0%) occurred in the North of Brazil, 43 (21.6%) in the Northeast, 80 (40.2%) in the Southeast, 46 (23.1%) in the South, and 12 (6.0%) in the Center-West region. Across all regions of the country, ICD10-E74 was predominant. CONCLUSIONS: This 13-year time-series study provides the first analysis of the number of infant deaths in Brazil attributable to IEMs known to be associated with sudden death.

Association between the thrombophilic polymorphisms MTHFR C677T, Factor V Leiden, and prothrombin G20210A and recurrent miscarriage in Brazilian women.

Some cases of recurrent first trimester miscarriage have a thrombotic etiology. The aim of this study was to investigate the prevalence of the most common thrombophilic mutations - factor V (FV) Leiden G1691A (FVL), prothrombin (FII) G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T - in women with recurrent miscarriages. In this case-control study, we included 137 women with two or more consecutive first-trimester miscarriages (£12 weeks of gestation) and 100 healthy women with no history of pregnancy loss, and with at least one living child. DNA was extracted from the patient samples, and the relevant genes (FVL, FII, and MTHFR) were amplified by PCR, followed by restriction fragment length polymorphism, to assess the polymorphisms in these genes. The allelic frequencies of polymorphisms were not significantly different between the case and control groups. Polymorphisms in the MTHFR, FVL, and FII genes were not associated with recurrent miscarriage during the first trimester of pregnancy in Brazilian women (P = 0.479; P = 0.491 and P = 0.107, respectively). However, the etiologic identification of genetic factors is important for genetic counseling.

p53 signaling pathway polymorphisms associated to recurrent pregnancy loss.

The p53 protein is known for performing essential functions in the maintenance of genomic stability in somatic cells and prevention of tumor formation. Studies of the p53 signaling pathway have suggested associations between some polymorphisms and infertility, post-in vitro fertilization implantation failure and recurrent abortions. The TP53 Pro72Arg polymorphism has been implicated as a risk factor for recurrent pregnancy loss (RPL); however, the association is controversial. In this study, our objective was to evaluate selected polymorphisms in genes of the p53 signalling pathway [TP53 c.215G>C (Pro72Arg), MDM2 c.14+309T>G (SNP309) and LIF c.1414T>G in the region 3' UTR] and determine their effect as risk factors for RPL. In a case-control study, we investigated 120 women with two or more pregnancy losses and 143 fertile control women reporting at least two live births and no history of pregnancy loss. When analyzed separately, the allele and genotype distributions of the polymorphisms in the two groups were not different. However, in a multivariate analysis adjusted for alcohol consumption, smoking, ethnicity, and number of pregnancies, the interaction between the genotypes TP53 Arg/Arg (rs1042522) and MDM2 TT (rs2279744) showed to be associated to RPL, increasing the risk for this condition (OR = 2.58, 95% CI: 1.31-5.07, p = 0.006). In conclusion, our study indicates that the combination of TP53 Arg/Arg (rs1042522) and MDM2 TT (rs2279744) genotypes may be a risk factor for RPL.

Monte-Carlo dosimetry on a realistic cell monolayer geometry exposed to alpha particles.

The energy and specific energy absorbed in the main cell compartments (nucleus and cytoplasm) in typical radiobiology experiments are usually estimated by calculations as they are not accessible for a direct measurement. In most of the work, the cell geometry is modelled using the combination of simple mathematical volumes. We propose a method based on high resolution confocal imaging and ion beam analysis (IBA) in order to import realistic cell nuclei geometries in Monte-Carlo simulations and thus take into account the variety of different geometries encountered in a typical cell population. Seventy-six cell nuclei have been imaged using confocal microscopy and their chemical composition has been measured using IBA. A cellular phantom was created from these data using the ImageJ image analysis software and imported in the Geant4 Monte-Carlo simulation toolkit. Total energy and specific energy distributions in the 76 cell nuclei have been calculated for two types of irradiation protocols: a 3 MeV alpha particle microbeam used for targeted irradiation and a ²³9Pu alpha source used for large angle random irradiation. Qualitative images of the energy deposited along the particle tracks have been produced and show good agreement with images of DNA double strand break signalling proteins obtained experimentally. The methodology presented in this paper provides microdosimetric quantities calculated from realistic cellular volumes. It is based on open-source oriented software that is publicly available.

Thermoresistance sperm tests are not predictive of potential fertility for cryopreserved bull semen.

Different studies demonstrate positive correlations between seminal variables determined in the laboratory and subsequent fertility after artificial insemination. It is clear, however, that there is still a deficiency in predicting in vivo fertility results of semen samples. The present study intended to verify the efficiency of rapid and slow thermoresistance tests in predicting fertility of frozen semen of bulls. Sperm from 64 ejaculates of 39 Nelore bulls (Bos indicus), aged 2-10 years, were cryopreserved in 0.5 mL straws. Thawed straws containing 30 x 10(6) sperm were analyzed for seminal variables in the laboratory and used to inseminate 4920 cows to evaluate fertility in the field. The ejaculates were frozen in a Tris-based extender and samples were evaluated for total motility after rapid (46 degrees C/30 min) and slow (38 degrees C/5h) thermoresistance tests by conventional and computerized (CASA) methods. Sperm samples were grouped according to their ability to retain motility after thermoresistance testing: group 0 (0% motility), group 1 (1-20% total motility), group 2 (21-40% total motility) and group 3 (>40% total motility). Correlation and association between these groups and fertility diagnosed by rectal palpation at 90 days were verified. Chi-square test demonstrated no association between motility groups and fertility (P>0.25) and both rapid and slow thermoresistance tests had a lesser correlation to fertility (r=0.11 and 0.14, respectively). These results demonstrated that these tests are not reliable in predicting in vivo behavior of bull frozen semen and are not effective to estimate fertility.

Avaliaçäo do desempenho técnico econômico de exploraçöes leiteiras em Divinópolis - MG, segundo a forma de produçäo / Economical and technical apraisal of a dairy cattle exploitations in Diviniopolis - MG, according to the production pattern

Com o objetivo de avaliar o desempenho técnico e econômico de exploraçöes leiteiras em Divinópolis - MG, estudaram-se 30 propriedades, sorteadas aleatoriamente entre as fornecedoras à Cooperativa local, agrupadas por forma de produçäo segundo a tipologia mercantil simples, pré-empresarial e empresarial. Os resultados revelaram prejuízos em todos os estratos, porém com dimensäo crescente no sentido de maior inserçäo no modo capitalista de produçäo, configurando um retorno financeiro inversamente proporcional à aplicaçäo de capitais no processo produtivo. A medida que se aprimoram em eficiência técnica, as exploraçöes analisadas perdem em eficiência econômica, indicando que além de enfrentar uma relaçäo de trocas desfavorável, a atividade é substancialmente penalizada por tributos de gestöes deficientes

[Location of single skin lesions of paucibacillary leprosy]. / Localisation des lésions cutanées uniques de lèpre paucibacillaire.

In this paper the authors study the sites of single lesions in 317 paucibacillary patients registered at the outpatient units of the CMS Jorge Saldanha and the Curupaiti State Hospital in Rio de Janeiro, Brazil. The preferential sites of lesions in the population studied, their relation with age and sex and factors likely to influence their distribution are discussed. The findings are compared with other similar studies performed in Asia and Africa.

Teste cicloergometrico em portadores da sindrome de Wolff-Parkinson-White. / Cycloergometric test in patients with Wolff-Parkinson-White syndrome

Foram submetidos a teste cicloergometrico continuo (protocolo habitual) 30 pacientes (22 do sexo masculino) portadores da sindrome de Wolff-Parkinson_white (WPW). A idade variou de 13 a 70 anos. Nao havia evidencia de outras doencas nem estavam em tratamento com antiarritmicos. Durante o teste, nao foram observados sinais de comprometimento da funcao cardiaca nem arritmias significativas (4 pacientes haviam apresentado previamente taquiarritmias paroxisticas comprovadas). A onda delta permaneceu inalterada em 19 pacientes e nos 3 casos de WPW intermitente, o esforco nao determinou o seu aparecimento. Em 8 pacientes, submetidos a teste maximo, desapareceu a onda delta durante o esforco (mantendo-se o segmento PR curto), com frequencia cardiaca superior a 150 bpm. Neste subgrupo, a onda delta reapareceu apos o esforco (1 a 4 min), ainda com frequencia cardiaca superior a 100 bpm. Foi encontrada em 9 pacientes (30%) resposta isquemica indiscutivel, 1 deles evidenciou desaparecimento da onda delta durante o esforco. Os autores comentam a fisiopatologia das alteracoes eletrocardiograficas encontradas durante o exercicio e o mecanismo determinante de arritmias, concluindo que o teste ergometrico nao parece ser um metodo eficiente para inducao de arritmias e para analise de drogas antiarritmicas em portadores de WPW

Infarto do miocardio sem lesao significativa de arteria coronaria. Estudo de sete casos e revisao. / Myocardial infarction without significant lesion of the coronary artery. Study of 7 cases and review

No presente trabalho, sao descritos os achados cinecoronariograficos e os aspectos evoluativos de sete pacientes com infarto do miocardio transmural, caracterizado do ponto de vista clinico, eletrocardiografico e enzimatico. Todos eram do sexo masculino, com idade media de 35 anos e nao portadores de multiplos fatores de risco, sendo o tabagismo o fator mais presente. O exame cinecoronariografico foi realizado em todo o grupo, com um tempo medio de 90 dias apos o quadro agudo, nao sendo encontrada lesao coronariana significativa em nenhum dos casos, mas ventriculografia esquerda estava alterada em 5 deles.Obito, insuficiencia cardiaca, angor e disturbio de conducao estiveram presentes na evolucao. Ate o momento a patogenia, a incidencia e a historia natural deste tipo particular de infarto do miocardio nao sao claras, parecendo que trombose e espasmo coronariano podem explicar, em parte, a sua genese