Carbonate alteration of ophiolitic rocks in the Arabian–Nubian Shield of Egypt: sources and compositions of the carbonating fluid and implications for the formation of Au deposits

Ultramafic portions of ophiolitic fragments in the Arabian–Nubian Shield (ANS) show pervasive carbonate alteration forming various degrees of carbonated serpentinites and listvenitic rocks. Notwithstanding the extent of the alteration, little is known about the processes that caused it, the source of the CO2 or the conditions of alteration. This study investigates the mineralogy, stable (O, C) and radiogenic (Sr) isotope composition, and geochemistry of suites of variably carbonate altered ultramafics from the Meatiq area of the Central Eastern Desert (CED) of Egypt. The samples investigated include least-altered lizardite (Lz) serpentinites, antigorite (Atg) serpentinites and listvenitic rocks with associated carbonate and quartz veins. The C, O and Sr isotopes of the vein samples cluster between −8.1‰ and −6.8‰ for δ13C, +6.4‰ and +10.5‰ for δ18O, and 87Sr/86Sr of 0.7028–0.70344, and plot within the depleted mantle compositional field. The serpentinites isotopic compositions plot on a mixing trend between the depleted-mantle and sedimentary carbonate fields. The carbonate veins contain abundant carbonic (CO2±CH4±N2) and aqueous-carbonic (H2O-NaCl-CO2±CH4±N2) low salinity fluid, with trapping conditions of 270–300°C and 0.7–1.1 kbar. The serpentinites are enriched in Au, As, S and other fluid-mobile elements relative to primitive and depleted mantle. The extensively carbonated Atg-serpentinites contain significantly lower concentrations of these elements than the Lz-serpentinites suggesting that they were depleted during carbonate alteration. Fluid inclusion and stable isotope compositions of Au deposits in the CED are similar to those from the carbonate veins investigated in the study and we suggest that carbonation of ANS ophiolitic rocks due to influx of mantle-derived CO2-bearing fluids caused break down of Au-bearing minerals such as pentlandite, releasing Au and S to the hydrothermal fluids that later formed the Au-deposits. This is the first time that gold has been observed to be remobilized from rocks during the lizardite–antigorite transition

The Effect of Multisensory Stimulation on Weight Gain of Preterm Infants

BACKGROUND AND OBJECTIVE: Low birthweight is one the common problems of infants and one of the main health indicators of a society. Weight is one the major determinants of physical and mental development in infants, particularly preterm infants. The aim of this study is to investigate the effect of multisensory stimulation on weight gain of preterm infants. METHODS: In this double-blind clinical trial, 80 preterm infants born at 32-36 weeks gestational age, were randomly divided into two groups (control and multisensory stimulation). The intervention group received multisensory stimulation program consisting of 12-minute daily sessions, 5 times a week until the day of discharge and the control group received only the usual care. Infants were weighed every day until the day of discharge (IRCT registration code: 2016073114454N2). FINDINGS: No significant difference was observed between the two groups of preterm infants in terms of gestational age, birthweight and sex. The difference between mean weight gain on the first day and the day of discharge was 131.6&plusmn;10.1 g in the intervention group and 58.9&plusmn;10.2 g in the control group. The difference between the two groups was significant (p<0.001). CONCLUSION: The Results of the study revealed that using multisensory stimulation for weight gain of preterm infants is a cost-effective and effective method

Carbonation of ophiolitic ultramafic rocks: Listvenite formation in the Late Cretaceous ophiolites of eastern Iran

Late Cretaceous mantle peridotite of the Birjand ophiolite (eastern Iran) contains variably serpentinized and carbonated/listvenitized rocks. Transformation from harzburgite protolith to final listvenite (quartz + magnesite/± dolomite + relict Cr-spinel) reflects successive fluid-driven reactions, the products of which are preserved in outcrop. Transformation of harzburgite to listvenite starts with lizardite serpentinization, followed by contemporaneous carbonation and antigorite serpentinization, antigorite-talc-magnesite alteration, finally producing listvenite where alteration is most pervasive. The spectrum of listvenitic assemblages includes silica-carbonate, carbonate and silica listvenites with the latter (also known as birbirite) being the youngest, based on crosscutting relationships. The petrological observations and mineral assemblages suggest hydrothermal fluids responsible for the lizardite serpentinization had low aCO2, oxygen and sulfur fugacities, distinct from those causing antigorite serpentinization and carbonation/listvenitization, which had higher aCO2, aSiO2, and oxygen and sulfur fugacities. The carbonate and silica listvenite end-members indicate variations in aSiO2 and aCO2 of the percolating hydrothermal fluids, most likely driven by local variations in pH and temperature.Beyond the addition of H2O, serpentinization did not significantly redistribute major elements. Progressive infiltration of CO2-rich fluids and consequent carbonation segregated Mg into carbonate and Si into silica listvenites. Trace element mobility resulted in different enrichments of fluid-mobile, high field strength, and light rare earth elements in listvenites, indicating a “listvenite mobility sequence”.The δ13C, δ18O and 87Sr/86Sr values of magnesite and dolomite in carbonated lithologies and veins point to sedimentary carbonate as the main C source. Fluid-mobile element (e.g., As and Sb) patterns in carbonated lithologies are consistent with contribution of subducted sediments in a forearc setting, suggesting sediment-derived fluids. Such fluids were produced by expulsion of pore fluids and release of structurally bound fluid from carbonate-bearing sediments in the Sistan Suture Zone (SsSZ) accretionary complex at shallow parts of mantle wedge. The CO2-bearing fluids migrated up along the slab-mantle interface and circulated through the suture zone faults to be sequestered in mantle peridotites with marked element mobility signatures

Associated Factors with Neonatal Weight Loss After Birth

Background: Neonatal weight loss in the first few days of life is a common phenomenon yet limited information about weight loss after birth is available. Objectives: The present study aimed at determining associated factors with neonatal weight loss after birth in newborns. Methods: In this cross-sectional study, the sample included 982 healthy, term and singleton newborns that had referred to health centers of Ilam. The mother and neonate's demographic characteristics, and the mother's pregnancy, childbirth and postpartum data were collected by a questionnaire. The data was analyzed using univariate and multivariate statistical analysis using the SPSS software. Results: The mean NWL 3 to 5 days after birth was 129 ± 92 grams. Infants had lost 4.04 ± 3.19 of their birthweight. The results of multivariate analysis (logistic regression) showed that breastfeeding (OR = 7.228, CI: 4.707 - 11.099), cesarean section (OR = 4.429, CI: 3.166 - 6.196), female gender (OR = 3.080, CI: 2.201 - 4.309), mother's no experience of breast feeding (OR = 2.831, CI: 1.817 - 4.409), weighting more than 4000 grams (OR = 2.464, CI: 1.034 - 5.870) and jaundice (OR = 1.486, CI: 1.035 - 2.133) were amongst risk factors for neonatal weight loss (NWL) of more than 5, while risk factors forNWLof more than 7 included only breastfeeding (OR = 2.904, CI: 1.759 - 4.796), cesarean section (OR = 2.073, CI: 1.423 - 3.019), and female gender (OR = 1.850, CI: 1.254 - 2.730). Conclusions: The study findings revealed that breastfeeding and cesarean section are the strongest predictors of NWL. Therefore, it is necessary for infant-friendly hospitals to come up with strategies to reduce the rate of cesarean section and establish successful breastfeeding before mothers are discharged. © 2017, Journal of Comprehensive Pediatrics

The Effect of Probiotics on Reducing Hospitalization Duration in Infants With Hyperbilirubinemia

peer reviewedBackground: Approximately 60% of term and 80% of premature infants are hospitalized for hyperbilirubinemia in the first week of life. Hyperbilirubinemia is the most common cause of infant hospitalization and readmission. Due to the high frequency of hyperbilirubinemia in infants and the high costs of treatment, it is necessary to find a way to decrease hospitalization duration. Objectives: The aim of this study is to assess the adjunctive effect of probiotics on decreasing hospitalization time for infants with hyperbilirubinemia. Methods: In this randomized, controlled clinical trial, 92 term infants with hyperbilirubinemia who met the inclusion criteria were randomly assigned to either the probiotic or control group. Patients in both groups underwent common phototherapy. Once a day, those in the probiotic group were also given half of a capsule of Prokid probiotic, while those in the control group received half of a placebo capsule. The duration of phototherapy and hospitalization, the blood groups of mothers and infants, and each patient’s bilirubin levels before and after phototherapy, direct Coombs test results, and levels of hemoglobin, G6PD, and reticulocytes were recorded. Results: Data from 92 patients with a mean age of 5.25 ± 2.35 days underwent analysis. The control group had 47 (51.1%) patients with a mean age of 5.19 ± 2.51 days and the probiotic group had 45 (48.9%) patients with a mean age of 5.31 ± 2.19 days (P = 0.81). The 92 patients had a mean bilirubin level of 16.70 ± 3.07 mg/dL, with a mean of 16.42 ± 3.53 mg/dL in the control group and 17.00 2.49 mg/dL in the probiotic group (P = 0.37). The duration of hospitalization averaged 3.34 ± 0.70 days overall, with an average of 3.55 ± 0.74 days for the control group and 3.13 ± 0.70 days for the probiotic group. The probiotic group had a significantly lower hospitalization stay in comparison to the control group (P = 0.004). Conclusions: Our findings suggest that probiotics may be beneficial as an adjunct treatment for infants with hyperbilirubinemia by reducing the duration of hospitalization