163 research outputs found
Cytogenetical Studies in Range Grasses of Iran
Cytogenetical and breeding studies of range grasses are in hand. Present article describes preliminary cytogenetical analysis of wheatgrass (Agropyron) and bromegrass (Bromus) taxa (Agropyron trichophorum n = 21, A. pectinoforome n = 21), two different populations of A. repens (n = 28) and Bromus stenostachyus (n = 14). The species varied with regard to chiasma number and distribution. The highest value occurred in A. repens (Mako population). Heterogenity test for the paired samples showed lack of heterogenity for chiasmata indicating homogenity of Agropyron taxa. However a test for ring and rod bivalents showed significant differences between the two populations of A. repens indicating genomic differences. Multivalents occurred regularly except in A. pectiniforome showing diplontic behaviour. B-chromosomes occurred in Bromus stenostachyus which moved to the poles, but were seen as laggard too. UPGMA cluster analysis separated two populations of A. repens, indicating their genomic differences. Other meiotic variations noticed were: occurrence of a synezetic knot and cytomixis causing aneuploidy in B.stenostachyus; clumping and laggards occurred frequently, indicating heterozygosity of the taxa due to cross pollination
Factorial effect of process parameters on pharmaceutical characteristics of biodegradable PLGA microparticles
Among the drug delivery strategies intended to increase the bioavailability of drugs, the use of polymeric biodegradable microcarriers has shown a significant degree of success.The purpose of this study was developing a polymeric drug delivery system for a model drug: furosemide, which belongs to class IV of BCS (low solubility and low permeability), intended to oral administration and improving the stability and intestinal absorption of the drug.To achieve this goal, furosemide loaded poly (lactic-co-glycolic acid) (PLGA) microparticles were prepared by solvent evaporation method and characterized. To obtain an appropriate mathematical model with minimum experiments for optimization of formulation, a 24 full factorial design based on four independent variables (amount of polymer, emulsifier, volume of internal and external phases) was used to plan the experiments. The effects of these parameters on the drug loading efficiency were investigated. The release profiles of furosemide from microparticles were examined in simulated gastric fluid (SGF pH 1.2), simulated intestinal fluid (SIF pH 7.4) and phosphate buffer (pH: 7.4).The results of optimized formulation showed a narrow size distribution with an average diameter of 60 ± 5 μm and a drug loading of more than 60%. In simulated gastric fluid (SGF), less than 8% of furosemide was released from microparticles in 24 h and about 60% and 50% furosemide was released in 24 h in simulated intestinal fluid (SIF) and phosphate buffer, respectively.Results from this preliminary work showed that furosemide loaded PLGA microparticles can be successfully obtained through solvent-evaporation technique, with good morphological characteristics, high encapsulation efficiency and controlled drug release profile suitable for per oral administration.Keywords: Furosemide; PLGA microparticles; Full factorial design
Factorial effect of process parameters on pharmaceutical characteristics of biodegradable PLGA microparticles
Among the drug delivery strategies intended to increase the bioavailability of drugs, the use of polymeric biodegradable microcarriers has shown a significant degree of success.The purpose of this study was developing a polymeric drug delivery system for a model drug: furosemide, which belongs to class IV of BCS (low solubility and low permeability), intended to oral administration and improving the stability and intestinal absorption of the drug.To achieve this goal, furosemide loaded poly (lactic-co-glycolic acid) (PLGA) microparticles were prepared by solvent evaporation method and characterized. To obtain an appropriate mathematical model with minimum experiments for optimization of formulation, a 24 full factorial design based on four independent variables (amount of polymer, emulsifier, volume of internal and external phases) was used to plan the experiments. The effects of these parameters on the drug loading efficiency were investigated. The release profiles of furosemide from microparticles were examined in simulated gastric fluid (SGF pH 1.2), simulated intestinal fluid (SIF pH 7.4) and phosphate buffer (pH: 7.4).The results of optimized formulation showed a narrow size distribution with an average diameter of 60 ± 5 μm and a drug loading of more than 60%. In simulated gastric fluid (SGF), less than 8% of furosemide was released from microparticles in 24 h and about 60% and 50% furosemide was released in 24 h in simulated intestinal fluid (SIF) and phosphate buffer, respectively.Results from this preliminary work showed that furosemide loaded PLGA microparticles can be successfully obtained through solvent-evaporation technique, with good morphological characteristics, high encapsulation efficiency and controlled drug release profile suitable for per oral administration.Keywords: Furosemide; PLGA microparticles; Full factorial design
A Stochastic Approach to Shortcut Bridging in Programmable Matter
In a self-organizing particle system, an abstraction of programmable matter,
simple computational elements called particles with limited memory and
communication self-organize to solve system-wide problems of movement,
coordination, and configuration. In this paper, we consider a stochastic,
distributed, local, asynchronous algorithm for "shortcut bridging", in which
particles self-assemble bridges over gaps that simultaneously balance
minimizing the length and cost of the bridge. Army ants of the genus Eciton
have been observed exhibiting a similar behavior in their foraging trails,
dynamically adjusting their bridges to satisfy an efficiency trade-off using
local interactions. Using techniques from Markov chain analysis, we rigorously
analyze our algorithm, show it achieves a near-optimal balance between the
competing factors of path length and bridge cost, and prove that it exhibits a
dependence on the angle of the gap being "shortcut" similar to that of the ant
bridges. We also present simulation results that qualitatively compare our
algorithm with the army ant bridging behavior. Our work gives a plausible
explanation of how convergence to globally optimal configurations can be
achieved via local interactions by simple organisms (e.g., ants) with some
limited computational power and access to random bits. The proposed algorithm
also demonstrates the robustness of the stochastic approach to algorithms for
programmable matter, as it is a surprisingly simple extension of our previous
stochastic algorithm for compression.Comment: Published in Proc. of DNA23: DNA Computing and Molecular Programming
- 23rd International Conference, 2017. An updated journal version will appear
in the DNA23 Special Issue of Natural Computin
Association of Milk and Dairy Products Consumption During Pregnancy with Fetal and Neonatal Head Circumferences: A Systematic Review
Context: Milk and dairy products consumed by mothers seem to be effective for fetal and neonatal anthropometric measurements, because they contain various nutrients.
Objectives: The aim of this study was to systematically review the influence of milk and dairy products consumption by mothers on fetal and neonatal head circumferences.
Data Sources: Systematic searches were conducted in electronic databases including PubMed/MEDLINE, Scopus, ISI, Ovid, Embase, Medlib, Google Scholar, clinical trials and Cochrane central register of clinical trials.
Study Selection: All studies that assessed the relationship between milk and dairy products consumption in healthy females during pregnancy and fetal and neonatal head circumferences were included in our systematic review. Finally, seven studies were relevant that included five cohort studies, one cross-sectional study and one randomized clinical trial.
Data Extraction: This systematic review was performed based on the preferred reporting item for systematic reviews and meta-analysis (PRISMA) statement recommendation, and for quality assessment, the Newcastle-Ottawa scale (NOS) for cohort studies, the adapted NOS for a cross-sectional study and the Jadad quality assessment score for a randomized clinical trial, were used.
Results: Seven studies that comprised of more than 50000 pregnant females were included in this review. One cohort study, one cross-sectional study and one randomized controlled trial study showed that milk or dairy products consumption by pregnant mothers was not associated with neonatal birth head circumference, while three cohort studies reported that maternal milk or dairy products intake had a positive effect on neonatal birth head circumference. Two cohort studies showed that there was no relationship between maternal milk or dairy products consumption and fetal head circumference while a cross-sectional study reported that there was a positive relationship between milk or dairy products consumption during pregnancy and fetal head circumference.
Conclusions: Evidences in this field are limited and inconsistent. According to the findings, there is a positive association between milk and dairy products consumption by pregnant mothers and neonatal birth head circumference but there is no relationship between maternal milk and dairy products consumption and fetal head circumference. However, almost all studies emphasized the importance of milk and dairy products in the maternal diet as a source of valuable nutrients
Exploration of Finite 2D Square Grid by a Metamorphic Robotic System
We consider exploration of finite 2D square grid by a metamorphic robotic
system consisting of anonymous oblivious modules. The number of possible shapes
of a metamorphic robotic system grows as the number of modules increases. The
shape of the system serves as its memory and shows its functionality. We
consider the effect of global compass on the minimum number of modules
necessary to explore a finite 2D square grid. We show that if the modules agree
on the directions (north, south, east, and west), three modules are necessary
and sufficient for exploration from an arbitrary initial configuration,
otherwise five modules are necessary and sufficient for restricted initial
configurations
Frequent homozygous deletion of p16/CDKN2A gene in malignant gliomas of Iranian patients
Homozygous deletion is the main mechanism of CDKN2A gene inactivation in malignant gliomas. However different frequencies were reported for its deletion. In order to find the homozygous deletion frequency among Iranian patients, we have analyzed the status of CDKN2A gene in 40 malignant gliomas and examined their 1α and 2 exons by comparative multiplex Polymerase Chain Reaction (PCR), using D9S171 chromosomal marker as an internal control. We found homozygous deletion in 6 out of 7 cases (85.7) of anaplastic astrocytomas and 20 out of 33 cases (60.6) of glioblastoma multiforme, in total 26 out of 40 cases (65) of malignant gliomas. We also found that CDKN2A deleted patients were younger than CDKN2A non-deleted patients and that exon 2 was deleted more than exon 1α. © 2007 Asian Network for Scientific Information
The shear viscosity of carbon fibre suspension and its application for fibre length measurement
The viscosity of short carbon fibre suspensions in glycerol aqueous solution was measured using a bespoke vane-in-cup viscometer, where the carbon fibre has an aspect ratio from 450 to 2209. In the semi-concentrated regime, nL3 ranging from 20 to 4400, the suspensions demonstrated strong shear-thinning characteristics particularly at higher concentrations. The shear-thinning characteristic is strongly related to the crowding factor proposed by Kerekes, indicating that non-hydrodynamic interactions occur in the suspensions. The influence of fibre bending on viscosity emerges when the bending ratio is lower than 0.0028. An empirical model based on transient network formation and rupture was proposed and used to correlate the relative viscosity with fibre concentration nL3 and shear rate. Based on the model, a viscosity method is established to analyse the fibre length by measuring the viscosity of the fibre suspension using a bespoke vane-in-cup viscometer
Contovir - A new adjuvant therapy in recurrent respiratory papillomatosis: A case study
Background: Contovir is a mixture of herbal extracts (Tanacetum vulgare, Rossa canina, Urtica dioica) that is supplemented with selenium. Objectives: This study aimed to add Contovir to the classic treatment of recurrent respiratory papillomatosis (RRP) in order to decrease the severity and extent of the disease, elongate the surgical intervals and improve the sense of patient well-being. Furthermore, we had to adjust the prescribed drug dosage, since there were no previous findings available. Patients and Methods: This is a case study of RRP patients treated with Contovir as an adjuvant to the classic treatment, from March 2011 to February 2013, at an academic tertiary hospital (Rasoul-e-Akram hospital). All patients underwent surgical removal of papilloma and then were prescribed Contovir. Disease severity was quantified based on Derkay�s staging system. Results: Eight patients were enrolled in this study. The extent and severity of the disease improved in six cases. One had no response, and the severity of disease increased in one patient. Patients with supraglottic lesions had better responses to Contovir adjuvant therapy. No immediate or long-term side effects were reported. Conclusions: Although Contovir has been found to be an advantageous adjuvant for RRP treatment, further studies are called for to verify these findings. © 2016, Iranian Red Crescent Medical Journal
Contovir - A new adjuvant therapy in recurrent respiratory papillomatosis: A case study
Background: Contovir is a mixture of herbal extracts (Tanacetum vulgare, Rossa canina, Urtica dioica) that is supplemented with selenium. Objectives: This study aimed to add Contovir to the classic treatment of recurrent respiratory papillomatosis (RRP) in order to decrease the severity and extent of the disease, elongate the surgical intervals and improve the sense of patient well-being. Furthermore, we had to adjust the prescribed drug dosage, since there were no previous findings available. Patients and Methods: This is a case study of RRP patients treated with Contovir as an adjuvant to the classic treatment, from March 2011 to February 2013, at an academic tertiary hospital (Rasoul-e-Akram hospital). All patients underwent surgical removal of papilloma and then were prescribed Contovir. Disease severity was quantified based on Derkay�s staging system. Results: Eight patients were enrolled in this study. The extent and severity of the disease improved in six cases. One had no response, and the severity of disease increased in one patient. Patients with supraglottic lesions had better responses to Contovir adjuvant therapy. No immediate or long-term side effects were reported. Conclusions: Although Contovir has been found to be an advantageous adjuvant for RRP treatment, further studies are called for to verify these findings. © 2016, Iranian Red Crescent Medical Journal
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