RESUMO
The viscoelastic response of carrageenan hydrogels to large amplitude oscillatory shear (LAOS) has not received much attention in the literature in spite of its relevance in industrial application. A set of hybrid carrageenans with differing chemical compositions are gelled in the presence of KCl or NaCl, and their nonlinear viscoelastic responses are systematically compared with mixtures of kappa- and iota-carrageenans of equivalent kappa-carrageenan contents. Two categories of LAOS response are identified: strain softening and strain hardening gels. Strain softening gels show LAOS non-reversibility: when entering the nonlinear viscoelastic regime, the shear storage modulus G' decreases with increasing strain, and never recovers its linear value G0 after successive LAOS sweeps. In contrast to this, strain hardening carrageenan gels show a certain amount of LAOS reversibility: when entering the nonlinear regime, G' increases with strain and shows a maximum at strain γH. For strains applied below γH, G0 shows good reversibility and the strain hardening behavior is maintained. For strains larger than γH, G0 decreases significantly indicating an irreversible structural change in the elastic network. Strain hardening and elastic recovery after LAOS prevail for hybrid carrageenan and iota-carrageenan gels, but are only achieved when blends are gelled in NaCl, suggesting a phase separated structure with a certain degree of co-aggregated interface for mixed gels.
RESUMO
To determine a demographic overview of orthopoxvirus seroprevalence, we tested blood samples collected during 2003-2019 from France (n = 4,876), Bolivia (n = 601), Laos (n = 657), and Mali (n = 255) for neutralizing antibodies against vaccinia virus. In addition, we tested 4,448 of the 4,876 samples from France for neutralizing antibodies against cowpox virus. We confirmed extensive cross-immunity between the 2 viruses. Seroprevalence of antibodies was <1% in Bolivia, <5% in Laos, and 17.25% in Mali. In France, we found low prevalence of neutralizing antibodies in persons who were unvaccinated and vaccinated for smallpox, suggesting immunosenescence occurred in vaccinated persons, and smallpox vaccination compliance declined before the end of compulsory vaccination. Our results suggest that populations in Europe, Africa, Asia, and South America are susceptible to orthopoxvirus infections, which might have precipitated the emergence of orthopoxvirus infections such as the 2022 spread of monkeypox in Europe.
Assuntos
Doenças Transmissíveis , Orthopoxvirus , Varíola , Humanos , Varíola/prevenção & controle , Estudos Soroepidemiológicos , Bolívia/epidemiologia , Laos/epidemiologia , Mali , Anticorpos NeutralizantesRESUMO
HYPOTHESIS: The elastic contribution to the fluid dynamics of wormlike micellar solutions makes these fluids unique due to the distinctive self-assembled micellar network formed by tubular micelles. Measured mesoscopic scales of the micellar network related to the degree of entanglement can give guidelines for understanding the origin of elastic forces and their effect on rheological response. EXPERIMENTS: Different experiments were made as flow curves, rotating the internal or external cylinder in a Couette geometry, small and large oscillatory shear tests, and linear shear banding observations, all of them to determine how elastic forces modify the rheological behavior in systems made of different ratios of hexadecyltrimethylammonium bromide (CTAB)/sodium salicylate (NaSal) and different ratios of CTAB/NaNO3. Diffusive wave spectroscopy micro-rheology was also performed to measure the mean square displacements of microspheres embedded in the micellar fluids to obtain their high-frequency viscoelastic spectra. With this information, the entanglement index κ, the ratio of the total contour of the micelles to the entanglement length, was estimated and correlated with the rheological behavior. FINDINGS: The entanglement index is a valuable piece of information to understand the origin of the contribution of the elastic forces from a molecular point of view on the fluid dynamics of wormlike micelle solutions.
Assuntos
Hidrodinâmica , Micelas , Cetrimônio , Difusão , Reologia/métodosRESUMO
INTRODUCTION AND OBJECTIVES: Hepatitis B virus (HBV) is endemic in Lao PDR, with up to 10% chronic infections in adults. Dentists have high risk of exposure and transmission to their patients. The aim was to investigate the serological profiles of vaccination, exposure and susceptibility to HBV. In addition, we determined the knowledge, attitude and practice (KAP) of Lao dentists toward HBV. MATERIALS AND METHODS: Dentists and dental assistants were recruited from 186 private dental clinics in Vientiane Capital. They completed a KAP questionnaire and serum was tested by ELISA for HBV markers (anti-HB surface antigen, anti-core antigen, HBV surface antigen). RESULTS: 206 dentists and 111 dental workers aged between 18-63 years were included. Serology data showed that 37.8% had previous exposure (49.0% of males and 32.4% of females) and 5.0% were chronically infected (7.7% of males and 3.8% of females). Less than 15% had serological evidence of vaccination and 66.8% were unprotected against infection. Knowledge of HBV was mostly low, for example 61.8% were aware of the childhood HBV vaccine. Just over half said that they should give dental care to HBV carriers. About one quarter reported accidental blood exposure during the last 6 months but knowledge about procedures after exposure was low. CONCLUSIONS: Lao dentists are at high risk of occupational exposure to HBV but have low awareness and serological protection. There is a need to introduce mandatory vaccination, to strengthen occupational health in health care providers and to further develop the academic curricula of dental students.
Assuntos
Recursos Humanos em Odontologia/estatística & dados numéricos , Odontólogos/estatística & dados numéricos , Vírus da Hepatite B/isolamento & purificação , Hepatite B/diagnóstico , Hepatite B/epidemiologia , Adulto , Estudos Transversais , Recursos Humanos em Odontologia/psicologia , Odontólogos/psicologia , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Hepatite B/prevenção & controle , Anticorpos Anti-Hepatite B/sangue , Antígenos de Superfície da Hepatite B/sangue , Humanos , Laos , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Adulto JovemRESUMO
The Neotropical longhorned beetle tribe Hemilophini has been reviewed by Martins & Galileo (2014a, b) and currently contains 542 species (Monné 2017). Some of the most conspicuous longhorned beetle taxa are found in this tribe, for example species with a pair of cephalic horns (Phoebe Audinet-Serville, 1835), or others that strongly resemble to noxious Lycidae (Coleoptera) (e.g. Apeba Martins & Galileo, 1991, Calocosmus Chevrolat, 1862, or Lycidola Thomson, 1864) (see Lingafelter 2013; Martins & Galileo 2014a, b).
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Besouros , Animais , BolíviaRESUMO
PIP: The Economic and Social Council for Asia and the Pacific (ESCAP) held a regional workshop in Thailand in 1992 to demonstrate how women's involvement at all levels of environmentally sound and sustainable water supply and sanitation programs and projects could be made more effective, easier, and productive. Using the same modules, with the support of other organizations such as the Department of Development Support and Management Services, ESCAP conducted four more workshops in the Philippines, Lao People's Democratic Republic (PDR), Vietnam, and Thailand in 1995. In the Philippines, the National Commission on the Role of Filipino Women expressed its intention to adapt the modules for the country. In the Lao PDR, three project ideas were proposed which would assist the Lao Women Union in gaining knowledge on the planning, implementation, operation, and management of water supply and sanitation projects at the national, regional and project levels. In Vietnam, three main directions for action were identified for the promotion of close and active cooperation between the Rural Water Supply and Environmental Sanitation Centres and the system of the Women Union of Vietnam. In Thailand, the National Committee on Health and Environment of the National Commission on Women's Affairs expressed its willingness to seek budgetary allocation for the promotion of women's role in water supply and sanitation.^ieng
Assuntos
Educação , Desenvolvimento de Programas , Pesquisa , Saneamento , Nações Unidas , Abastecimento de Água , Direitos da Mulher , Mulheres , Ásia , Sudeste Asiático , Conservação dos Recursos Naturais , Países em Desenvolvimento , Economia , Meio Ambiente , Saúde , Agências Internacionais , Laos , Organização e Administração , Organizações , Filipinas , Saúde Pública , Fatores Socioeconômicos , Tailândia , VietnãRESUMO
PIP: Responses to the second worldwide survey of 80 nations on their population policy can be divided into 3 categories. First are countries with large official programs of family planning in existence: Egypt, Kenya, Tunisia, Barbados, Colombia, Panama, Trinidad and Tobago, China, India, Iran, Japan, Nepal, Pakistan, Philippines, Republic of Viet-nam, Singapore, Sri Lanka, Thailand, Turkey, Denmark, Netherlands, United Kingdom, Yugoslavia, Canada, and Fiji. Madagascar and New Zealand are starting programs. The second category is countries that encourage private family planning programs: Tanzania, Mexico, Israel, Cambodia, Bahrain, Jordan, Laos, Syria, Austria, France, West Germany, Finland, and Norway. Third are listed countries that do not officially support, or that forbid contraception: Gabon, Malawi, Zambia, Greece, Italy, and Spain. Thus Asia and North Africa have the most ambitious programs, but Europe and North America practice contraception universally.^ieng