Background: The vasoconstricting agents: nor-adrenaline and 5- hydroxytryptamine
(5-HT) have a stimulant action on smooth muscle contractility of the rat vas deferens.
Objective: This study aimed to investigate the effect of exposure to continuous
darkness and continuous light on the contractility of the vasa deferntia smooth
muscles from rats to applied nor-adrenaline and 5-HT.
Method: Male albino wistar rats were divided into 3 experimental groups. Group 1:
Control animals, were exposed to the ordinary photoperiod each day. Group 2: Rats
were kept in a dark room. Group 3: In a room under a bright artificial light.
All animals were killed after 4 weeks.
Results: Vasa deferentia preparations from continuous dark group of rats exhibited a
reduced reactivity with a significant lower maximal response to 5-HT than those from
control rats. The maximal response in the control vasa deferentia preparations were
nearly doubled compared with that of the continuous dark preparation where as they
responded to exogenous nor-adrenaline with no significant difference from those of
continuous dark animals. Vasa deferentia of continuous light animals responded with
decreased reactivity and a smaller maximal response to both vasoconstrictors
compared with that of control animals.
Conclusion: It is concluded that changes in the rhythm of the photoperiod have
considerable effects on the reactivity of the vasa deferentia smooth muscle from rats
to applied nor-adrenaline and 5-HT
This work presents the study of the dark current density and the capacitance for porous silicon prepared by photo-electrochemical etching for n-type silicon with laser power density of 10mw/cm2 and wavelength (650nm) under different anodization time (30,40,50,60) minute. The results obtained from this study shows different chara that different characteristic of porous diffecteristics for the different porous Silicon layers.
Monetary sterilization policies are one of the modern trends of monetary policy in rentier countries, specifically to confront the positive shocks in foreign assets flowing into the national economy and the impact of these shocks on monetary and real variables. And that the Central Bank contains these emergency increases in foreign exchange with the aim of avoiding the impact of this increase on the official local currency through its three main monetary tools, which are the rediscount rate, the legal reserve, and open market operations. As well as the relationship between the central bank and the objective of external balance, which is reflected in the balance of payments balance, the central bank resorts to managing the exchange rate
... Show MoreAbstract: The aim of the research identify the effect of using the five-finger strategy in learning a movement chain on the balance beam apparatus for students in the third stage in the College of Physical Education and Sports Science, as well as to identify which groups (experimental and controlling) are better in learning the kinematic chain on the balance beam device, has been used The experimental approach is to design the experimental and control groups with pre-and post-test. The research sample was represented by third-graders, as the third division (j) was chosen by lot to represent the experimental group, and a division Third (i) to represent the control group, after which (10) students from each division were tested by lot to repr
... Show MoreThe purpose of this study is to examine the moderating role of business environment on the relationship between Entrepreneurial Skills (ES) and business performance of Small Business (SB) in Iraq, Baghdad. This study aims to resolve the inconsistencies found in the contemporary literature regarding the relationship between ES and business performance. Questionnaire using a 5-point Likert scale was adopted from previous work to ascertain the responses of the respondents. Survey research design was adopted, and self-administered questionnaires were used to collect the data from small business owners in 9 districts in Baghdad the capital of Iraq. The analysis was conducted using SPSS version 23.0. The direct relationship and hierarchical regre
... Show MoreThe study of vegetative change of cities is one of the most important studies related to human life because of its direct correlation with the temporal conditions that occur. These include the economic problems that force people to move and look for job opportunities in the city, which leads to an increase in the population density of cities, especially for cities with an important economic and administrative location as in the capital city of Baghdad. In this study, the effect of the increasing in population density was analyzed on the urban planning of Baghdad city. The decreasing in vegetation was due to the increasing of urban areas on the outskirts of the city, which led to an increase in its area. Moreover, urban cities increased t
... Show MoreSome children are suffering from introversion in kindergartens , so it must be confront and obviated by specialists because it will inevitably lead to unsatisfactory results reflect negatively on the individual and the community together . And the introvert child is a miserable child incapable of social interaction or give - and - take with colleagues , lack of integration of the child to life leads to the obstruction of participation with his peers in various activities. Introversion causes a real emotional deficit to the children of kindergartens which limits of possibility of their intellectual development and mental growth and that because of their isolation and poor focus in education
... Show MoreThe design of components subjected to contact stress as local compressive stress is important in engineering application especially in ball and socket Joining. Two kinds of contact stress are introduced in the ball and socket joint, the first is from normal contact while the other is from sliding contact. Although joining two long links (drive shaft in steering cars) will cause the effect of flexural and tensional buckling stress in hollow columns through the ball and socket ends on the failure condition of the joining mechanism. In this paper the consideration of the combined effect of buckling Load and contact stress on the ball and socket joints have been taken, epically on the stress distribution in the contact area. Different
... Show MoreThe dividends is one of difficult and important decisions taken by the administration in the economic units, because this decision has a direct impact on the investor and economic unit, so the main objective of any investor is achieve earnings, as well as information borne by dividends about the earnings quality of the economic unit and the level and efficiency of management to achieving earnings.
The research aims at explaining the effect of the dividends policy on the earnings quality in the companies listed in the Iraq Stock Exchange. The Miller model was used to measu
... Show MoreBackground: Cleaning and shaping of root canals successfully requires high volumes of irrigation solutions that can only be applied to the apical third of root canal after enlargement with instrument, so the aim of this study was to evaluate and to compare the efficiency of Maxi-I-probe (side-vented needle), in the amount of root canal irrigant penetration for five different master apical file sizes (MAF) and four different degrees of coronal and middle thirds flaring. Materials and Methods: Two hundred resin blocks with simulated root canals were used in this study and divided into 5 major groups (40 for each) based on the size of master apical files (#20, #25, #30, #35, and #40). Each major group was subdivided into 4 subgroups depending
... Show MoreThe current study was conducted to find out the effect of the sediment source (sedimentary of Iraqi-Iranian borderline and Tigris River) on the content and distribution of feldspar minerals and their effect on the optical properties of these minerals in some soils of Wasit and Maysan province. Eight pedons were chosen to represent the study area, five of them represented sediments coming from the borderline, which included pedons of (Badra, Taj Al-Din, Al-Shihabi, Jassan, and Galat), while two of them represent the sediments of the Tigris River (Essaouira, Al-Dabouni). Finally, the pedon of Ali Al-Gharbi represented the mixing area of sediments of all the torrents coming from borderline and the sediments of the Tigris River. The diagnostic
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