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1.
The effects of dietary fat and eggshell cuticle removal on egg water loss, embryo growth, and hatchability were determined in eggs from broiler breeder hens at different ages. Hens were fed isocaloric diets containing one of three different types and levels of added fat. In addition, eggs were either left intact or washed to remove the eggshell cuticle prior to set. Cuticle removal increased egg water loss between 43 and 62 wk. Cuticle removal increased relative wet embryo weight at Week 52 and relative dry embryo weight at 52 and 62 wk. Furthermore, at 62 wk, diet and day of incubation interacted to affect wet embryo weight, and diet variably affected dry embryo weight. No treatment differences were observed for cumulative hatchability, rate of hatch, and relative yolk sac weight at Day 19 of incubation. It was concluded that cuticle removal and the addition of fat to breeder diets may influence embryonic growth without having any subsequent effects on hatchability.  相似文献   

2.
The effect of Bacillus sphaericus, at various concentrations, on hatching of phlebotomine sand fly eggs was examined using laboratory bioassays. Aqueous suspensions of B. sphaericus, strain 2362, inhibited hatching of eggs of Phlebotomus duboscqi and Sergentomyia schwetzi by 95% at concentrations as low as 0.05 and 0.11 mg/cm2, respectively. In contrast, B. sphaericus did not affect the ability of pupae to emerge as adults.  相似文献   

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The efficiencies of an enzyme method and the sodium hypochlorite method in hatching eggs of Taenia solium (Henan strain) were compared. The viability of the hatched oncospheres was determined by staining with trypan blue. For the former method, the hatching rate and viability percentage were 85.7% and 79.7%, respectively. The corresponding figures for the latter method were 97.9% and 86.7%, respectively. These findings indicate that the sodium hypochlorite method is a simple, efficient and practical method for hatching eggs of Taenia solium.  相似文献   

5.
In vitro studies were done on Echinostoma caproni eggs with fully developed miracidia to determine the effects of snail-conditioned water (SCW) from Biomphalaria glabrata on miracidial hatching in the light. Observations were made on miracidial hatching at 4, 8, 12, 16, 20, and 24 h in multiwell chambers in the presence of SCW (experimentals) versus controls in artificial spring water (ASW). The number of hatched eggs was significantly greater (Student's t-test, P<0.05) in SCW at all times as compared with those maintained in ASW. Significantly greater hatching was also obtained when snails were maintained in intact or perforated dialysis sacs in multiwell chambers as compared with sacs without snails. Agar plugs impregnated with SCW or the hydrophilic fraction of SCW that had been extracted in chloroform-methanol (2:1) did not influence significant hatching. However, the lipophilic fraction of the SCW extract caused significant hatching. Substances in SCW significantly increase hatching of E. caproni miracidia, but details on what these compounds are remain obscure.  相似文献   

6.
从结晶器下口出来的含氟连铸保护渣熔渣与二冷水接触过程中,大量的离子释放到水中导致水质发生改变,呈酸性的二冷水不仅加速了连铸设备的腐蚀,水中大幅增加的F-还会导致水污染。为了研究连铸保护渣熔渣对水质产生影响的机制,通过熔渣水浸实验研究了无氟、低氟和高氟连铸保护渣水浸过程中水质的变化规律。水浸实验结果表明,无氟保护渣熔渣水浸实验过程中水样的pH值在7~10之间;低氟保护渣水样的F-质量浓度为5~7 mg/L,pH值在7~10之间;而高氟保护渣水样的F-质量浓度高达35 mg/L,pH值在4~10之间。保护渣中阳离子通过离子交换溶出导致水样呈碱性,而F-的交换溶出则会导致水样呈酸性,因此,水样的pH值则是由两类离子交换过程共同决定。无氟或低氟保护渣中由于氟的降低而减少了F-的交换溶出,从而抑制了氟造成的水污染及强腐蚀性的酸性二冷水的生成。  相似文献   

7.
Aquaporin 1, a six-transmembrane domain protein, is a water channel present in many fluid-secreting and -absorbing cells. In Xenopus oocytes injected with aquaporin 1 complementary RNA, the application of forskolin or cyclic 8-bromo- adenosine 3',5'-monophosphate increased membrane permeability to water and triggered a cationic conductance. The cationic conductance was also induced by direct injection of protein kinase A (PKA) catalytic subunit, reduced by the kinase inhibitor H7, and blocked by HgCl2, an inhibitor of aquaporin 1. The cationic permeability of the aquaporin 1 channel is activated by a cyclic adenosine monophosphate-dependent mechanism that may involve direct or indirect phosphorylation by PKA.  相似文献   

8.
We report the effects of cetiedil, a new antisickling agent, on red cell membrane permeability. With fresh red cells containing normal levels of intracellular ATP, cetiedil increases membrane permeability to both sodium and potassium. With drug concentrations from 100 to 500 microM, net sodium gain exceeds net potassium loss, and the cells quickly swell. Changes are identical with normal and sickle red cells. Membrane permeability returns to normal after washing the cells in buffer free of cetiedil. In the absence of phosphate, ouabain potentiates the cetiedil effect. With external phosphate present, the effect of cetiedil is also enhanced, but ouabain is without effect. Our findings support the idea that the antisickling effect of cetiedil observed in vitro is secondary to cell swelling.  相似文献   

9.
BACKGROUND: De Vega type suturing dosage plasty is the intervention most widely used for relative insufficiency of the tricuspid valve (TV). In fact, this operation may be considered as an equivalent of prosthetic reconstruction of the fibrotic ring, shaping a fixed orifice for passage. Intrapulmonary pressure normalized as early as during the first months after surgery in patients with the mitral-tricuspid cardiac valvular disease. Under such conditions a rigid suture (prosthesis of the anulus) at the interface of the right atrium and ventricle is not physiological. METHODS: We used Maxon CV 2-0 (D+G) suture absorbable for 6 months. Xenopericardial pads were fixed at the edge of the suture. The pads were prepared by enzymatic and chemical processing. RESULTS: Operations were performed in 7 patients, the results were followed for up to 28 months. The size of the TV fibrotic ring was measured by transesophageal ultrasonography (Hewlett-Packard SONOS 1500; OMNIPLANE) on the operating table and for 2 years postoperation. No signs af tricuspid insufficiency were detected.  相似文献   

10.
Perilymph is separated from blood by a barrier called the blood-labyrinth or blood-perilymph barrier in analogy to the blood-brain or blood-cerebrospinal fluid barrier. These barriers consist mainly of vascular endothelial cells. To characterize the blood-labyrinth barrier we developed in vitro techniques for the quantitative determination of the osmotic water permeability and for the determination of changes in the diameter of isolated inner ear capillaries. Both techniques rely on measurement of the velocity of marker red cells trapped in the lumen of capillaries. The velocity of marker red cells is a measure for the capillary permeability when a water flux across the capillary wall is induced by an osmotic gradient or a measure for a change in the capillary diameter. With these techniques the osmotic water permeability coefficient (Pf) and the pH sensitivity of isolated capillaries from the spiral ligament of the inner ear was determined. Pf at 23 degrees C was (1.49 +/- 0.17) 10(-3) cm/s at pH 7.4 and (1.61 +/- 0.23) 10(-3) cm/s at pH 6.8 (n = 12: mean +/- SEM: n = number of tissues). Pf at 37 degrees C was (2.26 +/- 0.23) 10(-3) cm/s at pH 7.4 and (2.35 +/- 0.17) 10(-3) cm/s at pH 6.8 (n = 13). No change in capillary diameter was observed when the pH of the interstitial fluid was lowered from pH 7.4 to 6.8. These data demonstrate that Pf and the capillary diameter of spiral ligament capillaries are pH independent and suggest that water crosses the blood-labyrinth barrier via an aqueous pathway. Further, these data suggest that the relatively low Pf is another characteristic shared by the blood-labyrinth and the blood-brain barrier.  相似文献   

11.
张润华 《钢铁研究》2006,34(2):44-48
结合武钢某钢厂3座90 t转炉除尘废水处理技术改造工程的设计、施工和运行实践,分析"双文一塔"烟气除尘流程废水的水质、水量特征.提出了转炉除尘循环水水处理的最佳工艺流程,包括工艺设计、主要构筑物设计参数、设备选型以及稳定水质的措施等.实施改造后该钢厂转炉除尘废水由直排改为闭路循环,获得了巨大的经济效益和社会效益.  相似文献   

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A method for hatching second-stage larvae of Toxocara cati is described. Whole adult worms are processed by centrifugation in the presence of hypochlorite which allows the grinding step to be eliminated. The technique is more rapid and a high yield is obtained.  相似文献   

15.
While factors other than competition and regulation influence hospital's behavior, these two strategies have dominated the health policy debate. To examine the impact of these two competing strategies on patients and hospitals, the authors examine experiences in Baltimore, which has followed a regulatory strategy since the early 1970s, and Minneapolis/St. Paul, which has pursued a competitive strategy during the same time frame. Compared with the national average, both strategies had only a minor impact on containing hospital costs per capita, but they influenced hospital productivity, cost per discharge, and utilization in different ways.  相似文献   

16.
Examined whether marital discord over childrearing contributes to child behavior problems after taking into account general marital adjustment, and if child age moderates associations between child behavior problems and either general marital adjustment or marital discord over childrearing. Participants were 146 two-parent families seeking services for their child's (4 to 9 years of age) conduct problems. Data on marital functioning and child behavior problems were collected from both parents. Mothers' and fathers' reports of marital discord over childrearing related positively to child externalizing problems after accounting for general marital adjustment. Child age moderated associations between fathers' reports of general marital adjustment and both internalizing and externalizing child problems, with associations being stronger in families with younger children. The discussion highlights the role that developmental factors may play in understanding the link between marital and child behavior problems in clinic-referred families.  相似文献   

17.
Dose-dependent water exchange times and intracellular water contents were measured by NMR (nuclear magnetic resonance) in erythrocytes and mitochondria interacted with the anti-anginal and anti-arrhytmic agent, amiodarone. Addition of the drug up to 26 microM yielded 80% enhancement of the water exchange rate in erythrocytes at 37 degrees C and 41% enhancement at 22 degrees C with 40% and 9%, respectively, increases in the intracellular water content. Similar enhancements were obtained in mitochondria at 22 degrees C. The data suggests a somewhat higher affinity of amiodarone to mitochondrial than to erythrocyte membranes.  相似文献   

18.
The freshwater snail Lymnaea stagnalis was exposed to cadmium concentrations of 0, 25, 50, 100, 200, and 400 microgram liter-1. The influence of this highly toxic metal on various stages of reproduction (number of egg masses, number of eggs, embryo development, and hatching) was studied. Egg production ceased at 400 microgram Cd2+ liter-1 and hatching was reduced to 0.4% with 200 microgram liter-1 at 20 degreesC. The study revealed that embryo development was the most sensitive stage, the main anomalies observed depending on the Cd2+ concentration. At the highest concentration studied (400 microgram liter-1) the eggs were blocked in the first cleavage stage. At 100 and 200 microgram Cd2+ liter-1, development of the eggs was halted at various stages of embryogenesis (cleavage, gastrula, veliger, and prehatching) depending on their position in the egg masses. At concentrations of 25 to 100 microgram Cd2+ liter-1, development was slowed down and hatching occurred 5 to 15 days later than in the controls (controls hatched 12 to 13 days after laying). The results obtained demonstrate the effects of Cd2+ on reproduction and development in L. stagnalis and provide information on the targets affected (neuroendocrine control of laying or cell multiplication and organogenesis of the embryos). It is thus possible to predict the probability of survival of the species in an environment polluted with cadmium and to compare it with the effects of other pollutants in the same or other species.  相似文献   

19.
It is well known that arginine vasopressin (AVP) produces up to a 40-fold increase (0.1 to 4.0 microL/min.cm2) in net water flux across the amphibian urinary bladder under an osmotic gradient (mucosal side 10% hypotonic). No AVP effect is observed when the gradient is in the opposite direction (serosal hypotonic). Similar asymmetrical behavior to osmotic gradients occurs in the frog corneal epithelium. This rectification phenomenon has not been satisfactorily explained. We measured net water fluxes in bladder sacs and confirmed that AVP has no effect when the serosal bath is hypotonic. We reasoned that the 'abnormal' serosal osmolarity was inducing changes in membrane water permeability, the very parameter being measured. Thus, we studied the effect of solution osmolarity on diffusional water flow (Jdw) across the frog bladder using 3H2O. As expected, AVP doubled Jdw (in either direction from 12 to 21 microL/min.cm2) when the serosal solution was iso-osmolar regardless of mucosal osmolarity. However, in the AVP-stimulated bladders, hypo-osmolarity of the serosal solution reduced Jdw by 42%, an effect that was reversible when normal osmolarity was re-established. Amphotericin B (instead of AVP) was used to irreversibly increase the permeability to water of the apical membrane. Under these conditions, basolateral hypotonicity also reversibly decreased Jdw by 32%, suggesting the basolateral membrane as the site where permeability is reduced. SEM and TEM of the tissue shows extreme swelling when it was exposed to serosal hypotonicity with or without AVP and typical surface morphology changes following hormone stimulation. We conclude that this swelling may initiate a signaling mechanism that reduces basolateral water permeability. These findings constitute evidence of basolateral water channel permeability regulation, which can also contribute to cell volume regulation.  相似文献   

20.
This study investigated the recovery of pancreatic insulin content during human islet isolation prior to and after digestion-filtration, continuous Hanks-Ficoll gradient purification (n = 20), and 3-4 day culture at 22 degrees C (n = 6). The native insulin content varied in a wide range from 28.4 U to 360.8 U/pancreas. After digestion the initially measured average insulin content of 115.8 +/- 20.8 U/pancreas (mean +/- SEM) increased to 264.6 +/- 22.8% (p < 0.001). This increase of insulin during pancreas digestion was attributed to the asymetrical distribution of insulin within the pancreas. Sampling of insulin within the pancreatic caput seemed not to be representative for the insulin content of the complete native organ, because the ratio of insulin per gram tissue within the pancreatic cauda compared to the caput (n = 5) was 2.4 +/- 0.4 (p < 0.05). After purification total insulin recovery was 55.3 +/- 4.8% (p < 0.001). Because recovery of islet equivalent number (IEQ) (83.7 +/- 4.4%) exceeded insulin recovery, insulin/IEQ ratio decreased from 656.8 +/- 70.6 microU/IEQ before purification to 436.4 +/- 58.1 microU/IEQ (p < 0.001) after purification. After 22 degrees C culture (n = 6) recovery of insulin and IEQ was 80.1 +/- 8.1% (p < 0.05) and 92.8 +/- 3.5% (p = NS), respectively. Insulin content per IEQ decreased to 85.8 +/- 6.5% (p < 0.05). This study clearly shows that most of islet insulin is lost during purification. This seems to be caused rather by an amplified insulin release than by the loss of islets itself. This release may facilitate the separation of endocrine and exocrine tissue by gradient centrifugation, but may also accelerate islet exhaustion detrimental for long-term insulin independence.  相似文献   

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