Mid-infrared optical characterization of thin SiNx membranes.

The investigation of the optical constants (e.g., the refractive index n and the extinction coefficient κ) has been performed in the mid-infrared spectrum for various silicon nitride (SiNx) configurations. By exploiting the transfer matrix method formulation, photometric measurements of transmission and reflection have been used for iteratively calculating the optical parameters of interest. To ensure the reliability of the n and κ, the same material from which such parameters were extracted was deposited for three different thicknesses, e.g., 600, 200, and 100 nm. While the former is optically characterized, the remaining two are used for validation purposes. For each experimental/calculated comparison, the average (made over the whole considered spectrum interval) of the relative error never exceeds 1.5%, which ensures the correctness of the given n and κ. For the sake of completeness, a detailed analysis of the intrinsic limitations arising from the very nature of the method will also be conducted.

The apoptotic response to strenuous exercise of the gastrocnemius and solues muscle fibers in rats.

The purposes of this study were to investigate the effects of strenuous exercise on apoptosis of the gastrocnemius and soleus muscle fibers and clarify the role of oxidative metabolism in the strenuous exercise-induced apoptosis. The experiment was designed with 49 (n = 49) male, 24-week-old, L. Wistar albino rats. Strenuous exercise model was applied to 42 (n = 42) rats and seven (n = 7) rats served as rested controls. All rats were randomly assigned to one of the following groups (n = 7): rested control (C), immediately after exercise (0 h) and 3, 6, 12, 24, and 48 h after exercise. Apoptotic nuclei were shown by single stranded DNA (ssDNA) determination. Oxidative damage in mitochondrial fractions of the muscle tissues was evaluated by malondialdehyde (MDA) levels and reduced/oxidized glutathione (GSH/GSSG) ratios. Caspase-9, -8 and -3 activities and the level of cytochrome c (Cyt c) were measured in the cytosolic fractions of muscle tissues to follow mitochondrial-dependent (intrinsic) or ligand-mediated death receptor (extrinsic) pathways of apoptosis. Plasma interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) levels were also determined. Based on our results, apoptosis is significantly triggered in muscle fibers by strenuous exercise (P < 0.05). Apoptosis in the soleus muscle tissues mostly depends on the intrinsic pathway and may be triggered by increased oxidative stress. In contrast, extrinsic pathway of apoptosis was predominant in the gastrocnemius muscle and increases of TNF-alpha and IL-6 may play a significant role.

Attitudes and practices of breastfeeding mothers regarding fasting in Ramadan.

OBJECTIVE: To investigate the attitudes and practices of breastfeeding mothers regarding fasting in Ramadan. DESIGN: Cross-sectional observational survey. SETTING: Well-child care clinic at Ankara University Medical School and a health station serving an impoverished population in Ankara, Turkey. PARTICIPANTS: Breastfeeding mothers of infants aged 12 months or younger. MAIN OUTCOME MEASURES: Fasting during Ramadan. RESULTS: Of the 164 participating mothers, 61 (37%) were from the health station and 103 (63%) from the university clinic. Most mothers were older than 25 years of age (55%), had more than primary school education (64%), a single child (53%), were living in a nuclear family setting (70%), supplementing breastfeeding (73%) and fasting (52%). Among the 129 mothers of infants aged 6 months or younger, 22% perceived a decrease in their breast milk and 23% an increase in the amount of solid supplements the infant was receiving. Belief that breastfeeding mothers should fast (RR = 6.45, 95% CI: 2.44-17.06), that fasting does not decrease breast milk (RR = 6.24, 95% CI: 1.85-21.05), receiving well-child care at the health station (RR = 3.14, 95% CI: 1.33-7.44), giving supplements (RR = 2.82, 95% CI: 1.09-7.27) and having multiple children (RR = 2.78, 95% CI: 1.23-6.28) were associated with fasting, in a logistic regression model. CONCLUSIONS: Fasting by breastfeeding mothers of infants is common during Ramadan, and rates are affected by beliefs of mothers on the effects of fasting on breastfeeding. We believe that child health care providers need to be knowledgeable about religious and cultural phenomena, study the effects of Ramadan fasting and form links with Islamic teachings to find religiously and culturally appropriate methods to combat the possible unfavourable effects for infants and children.