Effect Of Initial Time Research Articles

Early Enteral Feeding for Preterm or Low Birth Weight Infants: a Systematic Review and Meta-analysis.

Early enteral feeding has been associated with adverse outcomes such as necrotizing enterocolitis in preterm and low birth weight infants. To assess effects of early enteral feeding initiation within the first days after birth compared to delayed initiation. Medline, Scopus, Web of Science, CINAHL from inception to June 30, 2021. Randomized trials (RCTs) were included. Primary outcomes were mortality, morbidity, growth, neurodevelopment, feed intolerance, and duration of hospitalization. Data were extracted and pooled with random-effects models. We included 14 randomized controlled trials with 1505 participants in our primary analysis comparing early (<72 hours) to delayed (≥72 hours) enteral feeding initiation. Early initiation likely decreased mortality at discharge and 28 days (1292 participants, 12 trials, relative risk 0.69, 95% confidence interval [95% CI] 0.48-0.99, moderate certainty evidence) and duration of hospitalization (1100 participants, 10 trials, mean difference -3.20 days, 95%CI -5.74 to -0.66, moderate certainty evidence). The intervention may also decrease sepsis and weight at discharge. Based on low certainty evidence, early feeding may have little to no effect on necrotizing enterocolitis, feed intolerance, and days to regain birth weight. The evidence is very uncertain regarding the effect of initiation time on intraventricular hemorrhage, length, and head circumference at discharge. Enteral feeding within 72 hours after birth likely reduces the risk of mortality and length of hospital stay, may reduce the risk of sepsis, and may reduce weight at discharge.

The Effect of Stress Wave Interaction and Delay Timing on Blast-Induced Rock Damage and Fragmentation

Rock fragmentation by blasting is the most efficient way of rock breakage in hard rock mining applications. Fragmentation, as well as the properties of the fragments generated by the explosion, are of significant concern as the energy consumption at the mill is greatly affected by them. Dynamic loading of blasting generates a countless number of microcracks in the host rock, which despite the major cracks forming the fragments could not get enough time to coalesce and create macrocracks. These microstructures eventually impact the integrity of the intact rock and reduce its strength. Damage is considered as a scalar parameter, which accounts for the creation of flaws and microstructures in the rock, deteriorating its elasticity modulus. The stress waves and their interactions are the parameters that control damage around blastholes. In this study, using LS-DYNA numerical code, the effect of initiation timing on blast-induced rock damage and fragmentation is investigated. The results of the numerical models reveal the importance of the delays in damage as well as fragment size distribution. Delayed initiation provides enough timing for the cracks to grow, which preconditions the surrounding rock for the neighboring blasthole. The interaction between the stress waves resulting from the detonation of neighboring blastholes plays an important role in damage and fragmentation analysis. The optimum delay time can be obtained by considering the rise time and the duration of the stress pulse, the P and S wave travel times in the host rock, and the crack propagation time within the rock burden.

Modeling the causal effect of treatment initiation time on survival: Application to HIV/TB co-infection.

The timing of antiretroviral therapy (ART) initiation for HIV and tuberculosis (TB) co-infected patients needs to be considered carefully. CD4 cell count can be used to guide decision making about when to initiate ART. Evidence from recent randomized trials and observational studies generally supports early initiation but does not provide information about effects of initiation time on a continuous scale. In this article, we develop and apply a highly flexible structural proportional hazards model for characterizing the effect of treatment initiation time on a survival distribution. The model can be fitted using a weighted partial likelihood score function. Construction of both the score function and the weights must accommodate censoring of the treatment initiation time, the outcome, or both. The methods are applied to data on 4903 individuals with HIV/TB co-infection, derived from electronic health records in a large HIV care program in Kenya. We use a model formulation that flexibly captures the joint effects of ART initiation time and ART duration using natural cubic splines. The model is used to generate survival curves corresponding to specific treatment initiation times; and to identify optimal times for ART initiation for subgroups defined by CD4 count at time of TB diagnosis. Our findings potentially provide 'higher resolution' information about the relationship between ART timing and mortality, and about the differential effect of ART timing within CD4 subgroups.

Low temperature plasma-initiated precipitation copolymerization of styrene and maleic anhydride

In this study, we show that the plasma-initiated polymerization (PIP) can be carried out at ambient pressure using the dielectric barrier discharge (DBD) technology. The structure of styrene-maleic anhydride copolymer (SMA) is analyzed by 1H and 13C-NMR. The effects of initiation time, gas flow rate, post-polymerization time, and temperature on yield are also discussed. The results show that SMA exhibits a dominant alternating structure. The yield of SMA increases with the increase of initiation time and polymerization temperature, remains unchanged with the increase of flow rate, and decreases rapidly with the increase of St-MAH molar ratio. The PIP in this experiment is shown to follow the free-radical polymerization mechanism and the process of the polymerization is also discussed. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Low Temperature Plasma-Initiated Copolymerization of Acrylamide and Sodium Acrylate

The copolymerization of AM and AANa was initiated by plasma at ambient temperature and pressure by the dielectric barrier discharge technology in this work. The alternative copolymers are confirmed by FTIR. The effect of initiation time, polymerization temperature, monomer mass fraction, mole rate of AM to AANa and postpolymerization time on the conversion rate and molecular weight of the copolymers were studied. The molecular weight of the copolymers can be further increased by post-polymerization,and the plasma-initiated polymerization in this experiment was proven to follow the free radical polymerization mechanism.

Low temperature plasma-initiated copolymerization of styrene and maleic anhydride

In this study we show that the plasma-initiated polymerization can be carried out at ambient temperature and pressure using the dielectric barrier discharge technology. The structure of styrene-maleic anhydride copolymer (SMA) is analyzed by Fourier transform infrared and H1 NMR. The effects of initiation time, postpolymerization time, and polymerization temperature on conversion are also discussed. The results show that SMA exhibits a dominant alternating structure, the conversion increases with increasing initiation time, postpolymerization time, and polymerization temperature, and the plasma-initiated polymerization in this experiment is proven to follow the free radical polymerization mechanism.

Surface modification of lyocell fibres by graft copolymerization of thermo-sensitive poly- N-isopropylacrylamide

Thermo-sensitive poly- N-isopropylacrylamide (poly-NIPAAm) was grafted onto lyocell fibres using cerium ammonium nitrate (CAN) as initiator. The effects of initiation time, initiator concentration, monomer concentration and grafting time on the degree of grafting were investigated. A 15–60 min exposure time, 7.5 mM CAN solution concentration and a 0.5–1 mM NIPAAm monomer concentration were optimal for obtaining a maximum degree of grafting (60–70% at 24 h grafting time) of poly-NIPAAm on lyocell fibres. Higher degree of grafting was obtained increasing the grafting time, such as 120% at 72 h. The properties of the obtained poly-NIPAAm/lyocell copolymer were also investigated. Specifically, the effects of temperature and degree of grafting of poly-NIPAAm on the swelling behaviour of the copolymer were experimentally determined. Moreover, structural characterization, thermal behaviour and morphology of the poly-NIPAAm/lyocell copolymers were examined by Fourier Transform Infrared Spectroscopy (FTIR), Differencial Scanning Calorimetry (DSC) and Scanning electron microscopy (SEM) techniques, respectively.

Specific Resistance Measurements: Methods and Procedures

A computer‐aided data acquisition system was used with three sludges, two chemical‐conditioning systems and nine support media to investigate the effect of slurry solids concentration on specific resistance, the effect of initial time and filtrate volume readings on filtration data, and factors affecting the precision and accuracy of specific resistance measurements. The results of the study show that: (1) The specific resistance of a flocculent slurry is a very strong function of suspended solids concentration at low concentrations and relatively independent of concentration at high values; (2) improper determinations of the onset of filtration or errors in filtrate volume measurements produce slurry filtration data that do not fit the standard model (nonsynchronous data); and (3) specific resistance values are not as accurate and translatable as they might be because of differences in methods used in different laboratories. Several suggestions for improving the translatability of specific resistance mea...