Investigation on tensile properties of plain and nanoclay reinforced syntactic foams

Tensile properties of plain and nanoclay reinforced epoxy matrix syntactic foams with three different sizes of ceramic microballoons are investigated experimentally. Nine series of plain syntactic foams with 20, 40 and 60 volume fractions of microballoons are prepared and tested to study the volume fraction and size effects. Also nano syntactic foams specimens with six different weight fractions of nanoclay (0, 1, 2, 3, 5 & 7%) are tested and the effect of nanoclay content on the tensile properties is investigated. In addition to tensile tests, fracture modes of all syntactic foams are considered thoroughly by using scanning electron microscopy (SEM)

Identification of Pleuronectiformes species in the Persian Gulf (Khuzestan province) using morphometrics and meristics characteristics

This study was carried out to identify the different species of Pleuronectiformes order in the Khuzestan province waters (Persian Gulf) from March 2003 to June 2005. A Total of 671 specimens were collected by bottom trawl or from 7 main landings. The sampling period was seasonal. 36 main morphometric and meristic characteristics were measured. The results showed that 6 families of Soleidae, Cynoglossidae, Paralichtidae, Bothidae, Psettodidae and Citharidae are found in the studied area consist of 25 species of: Brachirus orentalis, Solea elongata, Monochirus lutenus, Parachirus marmoratus (family Soleidae); Cynoglossus ard, C. bilineatus, C. Puncticeps, C. durbanensis, C. lachneri (family Cynoglossidae); Pseudorombus annulatus, P. elevatus, P. arsius, P. malayanus, P. navaleusis, Paralichthodes algoensis, Poecilopstei javanicus (family Paralichtidae); Arnoglossus aspilos, A. arabicus, Engwrosopon grandisquama, Laeopes guentheri, L. natalensis, L. pectoralis, Psettina brevirictis (family Bothidae); Psettodes erumei (family Psettodidae) and Citharoides macrolepis (family Citharidae)

WEIGHTED RIESZ BASES IN G-FUSION FRAMES AND THEIR PERTURBATION

In this paper, we introduce orthonormal and Riesz bases for g-fusion frames and show that the weights have basic roles. Next, we prove an effective theorem between frames and g-fusion frames by using an operator. Finally, perturbations of g-fusion frames will be presented

Comparison between the Effects of Green and Black Tea, and Fluoride on Microhardness and Prevention of Demineralization of Deciduous Teeth Enamel

BACKGROUND AND OBJECTIVE: Dental caries in preschool children impose serious problems on parents and children due to lack of cooperation. Since tea leaves contain fluoride and polyphenol, this study was conducted to compare the effects of green and black tea, and fluoride in preventing demineralization of deciduous teeth enamel.  METHODS: This experimental study was performed on 40 extracted human deciduous incisors. The teeth were divided into 4 groups of 10 and were then placed in distilled water, green tea, black tea and oral sodium fluoride (0.05) for four minutes in seven consecutive days. Surface microhardness before and after tooth extraction was determined in these four solutions by Micro Vickers Hardness Testing Machine. To cause primary caries, each sample was kept for one week in demineralization solution and the concentrations of the released calcium, phosphorus and fluoride ions were analyzed by spectrophotometric and potentiometric laboratory methods.  FINDINGS: Primary microhardness showed no significant difference between the groups. Secondary microhardness compared to primary microhardness in the two groups of green tea (mean of 317 ± 65.47 to 386 ± 85.42, p = 0.003) and fluoride (mean of 319 ± 71.76 to 446 ± 117.15, p = 0.003) increased significantly. The concentration of calcium and phosphorus ions in the four study groups showed a significant difference after being placed in the demineralization solution (p = 0.001) (p = 0.003). However, this difference was not observed in fluoride concentrations.   CONCLUSION: The results of this study showed that drinking green tea can increase the microhardness and green and black tea increase the resistance to demineralization of the deciduous teeth enamel.&nbsp

Persistently modified h-channels after complex febrile seizures convert the seizure-induced enhancement of inhibition to hyperexcitability.

Febrile seizures are the most common type of developmental seizures, affecting up to 5% of children. Experimental complex febrile seizures involving the immature rat hippocampus led to a persistent lowering of seizure threshold despite an upregulation of inhibition. Here we provide a mechanistic resolution to this paradox by showing that, in the hippocampus of rats that had febrile seizures, the long-lasting enhancement of the widely expressed intrinsic membrane conductance Ih converts the potentiated synaptic inhibition to hyperexcitability in a frequency-dependent manner. The altered gain of this molecular inhibition-excitation converter reveals a new mechanism for controlling the balance of excitation-inhibition in the limbic system. In addition, here we show for the first time that h-channels are modified in a human neurological disease paradigm

Trout farms and other human activities effects on Cheshmehkileh river ecosystem in Tonekabon

Cheshmehkileh River and adjacent mountainous streams, play a strategic role as a historical axis for anthropogenic civilization, human welfare also habitat and migration pathway of commercial – biologic valuable fishes e.g. Caspian trout, Caspian kuttum, members of Cyprinidae family in south Caspian Sea drainage. Treats such as overfishing of Caspian trout and Red spotted trout stocks in mountainous headwaters, barriers construction and manipulations those are out of river carrying capacity developed by human activities, affected normal function of river as well. Sand mining big factories establishment next to the river, legal and illegal trade of river sediments, direct entry of Tonekabon landfill leakage into the river, development of Rainbow trout farms since 3 decades and huge effluents into the river containing dead fish and types of solids, escapement of cultured Rainbow trouts into the river, … are major minimum factors which needs basic information for integrating inclusively drainage management system. Cheshmehkileh River contains Headwaters of Dohezar (Daryasar & Nusha), Sehezar and Valamroud rivers during 13 monthly sampling phases between September 2009 and October 2010 based on macrozoobenthoses investigations by EPT, EPT/C EPA protocols, measurements of nominated physic-chemical and microbiologic parameters. Probability of Rainbow trouts escapement and invasion, existence, nutrition in Cheshmehkileh environment indeed investigated. Data analysis explained significant differences (P<0.05) between groups of measured parameters in different sampling stations. Dendogram of clustered analysis based on consolidation of major biologic/ physic-chemical and microbiologic parameters, separated stations No. 1, 3, 2, 4 in one group and remained classified in different groups. Station 8 and 9 similarly separated which expressed general similarities according to Sehezar river environment which were differs in comparison with other stations. Station 11 separated according to its natural quality of water and environment. Similarities between station 10 to Sehezar river stations 8 and 9 expressed general influence of Sehezar River more than Dohezar River in Cheshmehkileh condition especially in station No. 10. High scores of EPT and EPT/C indices in upstream stations 1, 3 and 8 also low score of indices in stations 7, 13 and 6 expressed levels of environment quality between these groups of stations. Maximum average biomass of macroinvertebrates belongs to Trichoptera order in Cheshmehkileh River. Significant decrease of biomass in stations 11, 12 and 13 in comparison with other stations stated environment degradation in mentioned stations relevant to excessive sand mining as well. Pollution resistant groups of invertebrates significantly increased in downstreams against upstream stations. Also disappearing of Plecoptera order in station No. 7, 9, 10 and 13 stated low quality of environment in comparison with upstream stations. Confirmation of effects quality and quantity for point and non-point sources of imported pollutants require specific management considerations in order to present exploitations, pollutants control and emergencies for river monitoring in forthcoming years

The influences of nursing transformational leadership style on the quality of nurses’ working lives in Taiwan: a cross-sectional quantitative study

- Background: Taiwan’s NHI system is one of the most successful health care models for countries around the globe. However, little research has demonstrated the mental health issues associated with nursing transformational leadership style under the NHI system, especially in the quality of nurses’ working lives in Taiwan. It is important to know the relationship between transformational leadership style and the mental health of nurses, organisational commitment and job satisfaction. The research aimed to understand the influences of nursing transformational leadership style on the quality of nurses’ working lives in Taiwan. The research hypothesis was that transformational leadership styles would have positive influence on the quality of nurses’ working lives. - Methods: This was a cross-sectional quantitative study. Nurses from each type of hospital ownership (private, public and religious) were recruited. Participation was voluntary and signed informed consent was obtained. The inclusion criteria were nurses with at least one year’s work experience in the hospitals. Self-administrated questionnaires were used. A total of 807 participants were contacted and 651 questionnaires were fully completed (response rate 80.7 %). A theory driven model was used to test the research hypotheses using structural equation modelling performed with AMOS 16.0. - Results: Transformational leadership contributes significantly to supervisor support. Workplace support, particularly from the supervisor, is an important mediator variable that explains the relationship between transformational leadership and job satisfaction. Organisational commitment was the strongest factor relevant to the general health well-being in Taiwanese nurses than job satisfaction. The hypothesized positive relationships between transformational leadership and all variables were supported by the data. - Conclusions: Our findings have important consequences for organisational health. Our model demonstrates a complete picture of the work relationships on the quality of nurses’ working lives. The results provided information about the subordinates’ perceptions of transformational nursing leadership styles and mental health outcomes in different hospital settings, as well as identified organisational factors that could improve the quality of nurses’ working lives