Structural, thermal and optical properties of TeO2-ZnO-CdO-BaO glasses doped with VO(2+).

The glasses with composition 64TeO2-15ZnO-(20-x)CdO-xBaO-1V2O5 (0⩽x⩽20 mol%) were prepared by conventional melt quenching technique. X-ray diffraction analysis was used to confirm the amorphous nature of the glasses. The optical absorption studies revealed that the cut-off wavelength (λα) decreases while optical band gap energy (Eopt) and Urbach energy (ΔE) values increase with an increase of BaO content. Refractive index (n) evaluated from Eopt was found to decrease with an increase of BaO content. The physical parameters such as density (ρ), molar volume (Vm), oxygen packing density (OPD), optical basicity (Λ), molar refraction (Rm), and metallization criterion (M) evaluated and discussed. FTIR and Raman spectroscopic studies showed that the glass network consists of TeO4, TeO3+1/TeO3 and ZnO4 units as basic structural units. The glass transition temperature (Tg) of glass sample, onset crystallization temperature (To) and thermal stability ΔT were determined from Differential Scanning Calorimetry (DSC). Using electron paramagnetic resonance (EPR) spectra of vanadium glasses the spin Hamiltonian parameters and dipolar hyperfine coupling parameters of VO(2+) ions were calculated. It was found that V(4+) ions in these glasses exist as VO(2+) in octahedral coordination with a tetragonal distortion and have C4V symmetry with ground state dxy. Tetragonality (Δg∥/Δg⊥) of vanadium ion sites exhibited non-linear variation with BaO content.

The World Health Organization's work on adolescent sexual and reproductive health.

This paper examines the contribution of the World Health Organization to the field of adolescent sexual and reproductive health (ASRH) from the early 1980s to the present. It is based on published documents and on the experiences of WHO staff members who have been part of much of this journey. It recalls the responses of the organization to the (then) new HIV/AIDS pandemic and to the first calls for a global public health response to early pregnancy. It also highlights selected milestones in the organization's work in the ASRH field over the last 25 years. It concludes with an analysis of where the ASRH field stands today and what the organization is doing to strengthen the epidemiologic and evidence base for action, to build consensus and coordination, and most importantly to support country level action, in cooperation with organizations within and outside the United Nations system. In defining its niche in a rapidly evolving and increasingly crowded field, the WHO's mission on ASRH is to contribute to a world in which the importance of ensuring the sexual and reproductive health of adolescents is understood, accepted, and acted upon by adolescents themselves, by their families and communities, by the workforces of different sectors, by civil society bodies, and by leaders and decision makers.

Reaching youth with out-of-facility HIV and reproductive health services: a systematic review.

PURPOSE: Many young people, particularly those who are marginalized and most at risk for HIV and reproductive health-related problems, cannot or will not seek traditional facility-based health services. Policies and programs are being implemented to provide them with these health services in the community. We sought to review the effectiveness of such approaches in increasing HIV and reproductive health service use. METHODS: A systematic literature review was undertaken to identify policies promoting or programs delivering HIV or reproductive health services in the community. We reviewed studies that evaluated uptake of services or commodities. Data from studies meeting inclusion criteria were qualitatively analyzed. RESULTS: Twenty studies met inclusion criteria, including 10 containing comparative data (e.g., before and after study or control study design). The studies generally demonstrated positive impact, although results varied across settings and approaches. The most successful approaches included mail-based chlamydia screening in the Netherlands, condom distribution via street outreach in Louisiana, home-based HIV counseling and testing in Malawi, and promotion of over-the-counter access to emergency contraception in various countries. CONCLUSION: Overall, this review suggests that out-of-facility approaches can be important avenues to reach youth. Continued evaluation is necessary to better understand specific approaches that can successfully deliver health services.

Tailoring clinical management practices to meet the special needs of adolescents: sexually transmitted infections.

Sexually transmitted infections are a major health risk to all sexually active adolescents and improving clinical management for this age group is of major importance. Currently, adolescents are managed in the same way as adults. This paper summarizes recommendations by the World Health Organization that services be more responsive to adolescent concerns about confidentiality, risk assessment be more attuned to their sexual behavioral patterns, and services be tailored to give more time for counseling, assessment of stage of maturity and continuity of reproductive health care.

Contraception for adolescents: social, clinical and service-delivery considerations.

A large proportion of the millions of adolescents worldwide who are sexually active have sex without using modern contraceptives or protection against sexually transmitted infections (STI). In many cases, this results in too-early (and often unwanted) pregnancies and STI, with negative consequences at different levels. Adolescents in general--and unmarried adolescents in particular--often find it difficult to obtain the contraceptives they need. Health workers are often unaware of the special needs of adolescents, and contraceptive services are only rarely provided in a manner that is accessible to adolescents. The World Health Organization stresses that age alone does not constitute a medical reason for denying any available contraceptive method to adolescents. However, it recommends that it is important for health workers to be well aware of the biomedical, psychological and social issues that affect how they can assist adolescents in making well-informed choices of contraceptive methods that suit their special needs, and in using the contraceptives, they choose in an effective manner.

Drawing in, working with and supporting communities in sexual health promotion.

PIP: A safe and supportive environment is a critical element of effective HIV infection prevention. Numerous intervention studies and grass-roots initiates have proved that even when people are highly aware of the dangers of AIDS, know fully well on HIV prevention and are motivated to avoid it, factors in the immediate and wider environment play a pivotal role in determining whether or not they can protect themselves. These factors include restrictive laws and policies, economic constraints, social and cultural pressures, and unavailability and poor accessibility to health services. Through the years, there has been a growing interest in environmental factors that influence HIV/sexually transmitted diseases (STDs) transmission, particularly on the importance of the community in promoting and safeguarding sexual health. Many communities around the world responded effectively and with compassion to the challenge of caring and supporting HIV/AIDS victims. By educating the public on HIV prevention and protection through safe sex practices, communities have contributed to the fight against AIDS/HIV and STDs. In most situations, carefully tailored actions directed at individual levels require a complementary set of carefully tailored actions at the level of the environmental level in order to overcome the environmental factors that prevent individuals from protecting themselves and promote their own health.^ieng