822 research outputs found
Monotonicity Results for Arithmetic Means of Concave and Convex Functions
By majorization approaches, some known results on monotonicity
of the arithmetic means of convex and concave functions are proved and
generalized once again
Effects of different levels of protein-to-energy ratios on nutrient digestibility and digestive enzyme activity in Leiothrix luteal
Effects of different levels of protein-to-energy ratios (PER) on nutrient utilization, digestive organs index and digestive enzymes activities in Leiothrix luteal were investigated in this research. It was found that different PER feedstuff had no significant effects on the utilization of dry matter (DM), calcium (Ca) and total phosphorus (TP). With the improvement of the PER, average daily feed intake (ADFI) gradually increased, the apparent utilization rate of energy and fat gradually improved, while the apparent utilization rate of crude protein increased at first and then decreased. Development of digestive organs of L. luteal was affected by the level of dietary PER, with the increase in PER, the digestive organ indices of muscular stomach, duodenum, jejunoileum and rectum exhibited a downward trend, the main influencing factors were the level of metabolizable energy in diets. With the intestinal tract moving backward, the relative activity of proteases gradually reduced, manifesting as pancreas > duodenum > jejunoileum. The relative activity of carbohydrate digestion enzymes gradually increased as the intestinal tract moved backward. With the improvement of PER, the relative activity of lipase gradually decreased in pancreas, duodenum, and jejunoileum. L. luteal possessed a strong ability to digest crude fiber and total phosphorus; the reason might be closely related to the types and quantities of intestinal flora, which was affected by the feeding habits of this bird. By comprehensively considering the nutrient utilization, digestive organ indices and digestive enzymes activities, the formula of PER II was more appropriate for nutritional needs of L. luteal in captivity.Keywords: Leiothrix luteal, protein-to-energy ratios, nutrients, digestion and utilization, enzyme activitiesAfrican Journal of Biotechnology Vol. 12(15), pp. 1902-190
同型半胱氨酸对人脐静脉内皮细胞线粒体膜电位的影响
Objective: To observe the changes of endothelial mitochondrial membrane potential(MMP)by building Hcy-induced endothelial impairment model in cultured human umbilical vein endothelial cells and to analyze the mechanism of Hcy-induced apoptosis.Methods: (1) Cultured HUVECs of term infant in vitro provide enough experimental materials. (2)The HUVECs are randomly divided into five groups: the control group does not add Hcy, the other groups add 0.01、0.1、1.0、3.0mmol/LHCY respectively, and put them together for 24 hours to detect the changes of MMP of the HUVECs at 3、6、12、24 hour.Results: There is no difference in the level of MMP in the HUVECs stimulated by HCY for 24 hours between the HCY0.01mmol/L group and the control group. Comparing with the control group,MMP reduces at 24 hour in the HCY0.1 mmol/L group ,at 6、12、24 hour in the HCY1.0 mmol/L group and at 3、6 hour(P<0.05)and obviously at 12、24 hour(P<0.01) in the HCY3.0 mmol/L group.In the same Hcy-induced group, MMP obviously reduces at 24 hour, >12h、6h、3h.At the same time, MMP obviously reduces at 3.0mmol/L Hcy-induced group, >1.0、0.1、0.01 mmol/L group and the control group.Conclusion: (1)HCY can injury endothelial function and induce apoptosis and it relates with concentration and time of HCY.(2) Mechanism of Hcy- induced endothelial apoptosis may relates the reduction of MMP.目的 探讨同型半胱氨酸诱导人脐静脉内皮细胞线粒体膜电位(MMP)的变化,了解血管内皮细胞发生细胞凋亡的机制。方法 无菌采集正常足月剖腹产胎儿脐带进行人脐静脉内皮细胞培养,取对数生长的人脐静脉内皮细胞制成细胞悬液,加含1%胎牛血清(FCS)的培养基(DMEM)处理细胞24h,使细胞稳定、同步化。随机分成五组:(1)空白组:仅加含1%FCS的DMEM5ml。(2)HCY0.01mmol/L组:1%FCS的DMEM+HCY终浓度为0.01 mmol/L 5ml。(3)HCY0.1 mmol/L组:1%FCS的DMEM+HCY终浓度为0.1mmol/L 5ml。(4) HCY1.0 mmol/L组:1%FCS的DMEM+HCY终浓度为1.0 mmol/L 5ml。(5)HCY3.0mmol/L组:1%FCS的DMEM+HCY终浓度为3.0 mmol/L 5ml。继续培养24h,每组3个样本。结果 不9同浓度及时间HCY对HUVECs线粒体膜电位的影响:MMP在HCY0.01mmol/L组和空白对照组间无差异性变化;在HCY0.1 mmol/L组于24h时出现下降(P<0.05);在HCY1.0mmol/L组于6h、12h、24h出现下降(P<0.05);在HCY3.0mmol/L组于3h、6h有下降(P<0.05),12h、24h明显降低(P<0.01)。同一浓度HCY作用24h时MMP最低,依次>12h、6h、3h。相同时间内,可以看到HCY浓度越高MMP降低越多,MMP在HCY3.0mmol/L组最低,依次>1.0、0.1及0.01和空白组,结论 HCY可导致MMP发生改变,其浓度及作用时间是影响因素。(1)相同时间内,HCY浓度越高MMP降低越多。(2)同一浓度HCY作用时间越长MMP越低。
Auroral Morphological Changes to the Formation of Auroral Spiral during the Late Substorm Recovery Phase: Polar UVI and Ground All-Sky Camera Observations
The ultraviolet imager (UVI) of the Polar spacecraft and an all-sky camera at
Longyearbyen contemporaneously detected an auroral vortex structure (so-called
"auroral spiral") on 10 January 1997. From space, the auroral spiral was
observed as a "small spot" (one of an azimuthally-aligned chain of similar
spots) in the poleward region of the main auroral oval from 18 h to 24 h
magnetic local time. These auroral spots were formed while the
substorm-associated auroral bulge was subsiding and several poleward-elongated
auroral streak-like structures appeared during the late substorm recovery
phase. During the spiral interval, the geomagnetically north-south and
east-west components of the geomagnetic field, which were observed at several
ground magnetic stations around Svalbard island, showed significant negative
and positive bays caused by the field-aligned currents related with the aurora
spiral appearance. The negative bays were reflected in the variations of local
geomagnetic activity index (SML) which was provided from the SuperMAG
magnetometer network at high latitudes. To pursue the spiral source region in
the magnetotail, we trace each UVI image along field lines to the magnetic
equatorial plane of the nightside magnetosphere using an empirical magnetic
field model. Interestingly, the magnetotail region corresponding to the auroral
spiral covered a broad region from Xgsm ~ -40 to -70 RE at Ygsm ~ 8 to 12 RE.
The appearance of this auroral spiral suggests that extensive areas of the
magnetotail (but local regions in the ionosphere) remain active even when the
substorm almost ceases, and geomagnetic conditions are almost stable.Comment: 39 Pages, 6 Figures (8 pages), 1 Table, and Supporting Information
file (including 2 Figures (8 pages) and 1 Movie
A novel multifunctional biomedical material based on polyacrylonitrile:preparation and characterization
Wet spun microfibers have great potential in the design of multifunctional controlled release materials. Curcumin (Cur) and vitamin E acetate (Vit. E Ac) were used as a model drug system to evaluate the potential application of the drug-loaded microfiber system for enhanced delivery. The drugs and polyacrylonitrile (PAN) were blended together and spun to produce the target drug-loaded microfiber using an improved wet-spinning method and then the microfibers were successfully woven into fabrics. Morphological, mechanical properties, thermal behavior, drug release performance characteristics, and cytocompatibility were determined. The drug-loaded microfiber had a lobed “kidney” shape with a height of 50 ~ 100 μm and width of 100 ~ 200 μm. The addition of Cur and Vit. E Ac had a great influence on the surface and cross section structure of the microfiber, leading to a rough surface having microvoids. X-ray diffraction and Fourier transform infrared spectroscopy indicated that the drugs were successfully encapsulated and dispersed evenly in the microfilament fiber. After drug loading, the mechanical performance of the microfilament changed, with the breaking strength improved slightly, but the tensile elongation increased significantly. Thermogravimetric results showed that the drug load had no apparent adverse effect on the thermal properties of the microfibers. However, drug release from the fiber, as determined through in-vitro experiments, is relatively low and this property is maintained over time. Furthermore, in-vitro cytocompatibility testing showed that no cytotoxicty on the L929 cells was found up to 5% and 10% respectively of the theoretical drug loading content (TDLC) of curcumin and vitamin E acetate. This study provides reference data to aid the development of multifunctional textiles and to explore their use in the biomedical material field
Ionospheric plasma flows associated with the formation of the distorted nightside end of a transpolar arc
We investigate ionospheric flow patterns from 28th January 2002 associated with the development of the nightside distorted end of a “J”-shaped Transpolar Arc (nightside distorted TPA). Based on the nightside ionospheric flows near to the TPA, detected by the SuperDARN radars, we discuss how the distortion of the nightside end toward the pre-midnight sector is produced. The “J”-shaped TPA was seen under southward Interplanetary Magnetic Field (IMF) conditions, in the presence of a dominant dawnward IMF-By component. At the onset time of the nightside distorted TPA, particular equatorward plasma flows at the TPA growth point were observed in the post-midnight sector, flowing out of the polar cap and then turning toward the pre-midnight sector of the main auroral oval along the distorted nightside part of the TPA. We suggest that these plasma flows play a key role in causing the nightside distortion of the TPA. SuperDARN also found ionospheric flows typically associated with “Tail Reconnection during IMF Northward Non-substorm Intervals” (TRINNIs) on the nightside main auroral oval before and during the TPA interval, indicating that nightside magnetic reconnection is an integral process to the formation of the nightside distorted TPA. During the TPA growth, SuperDARN also detected anti-sunward flows across the open-closed field line boundary on the dayside that indicate the occurrence of low-latitude dayside reconnection and ongoing Dungey cycle driving. This suggests that nightside distorted TPA can grow even in Dungey-cycle-driven plasma flow patterns
EXPERIMENTAL STUDY ON THE INHIBITORY EFFECT OF SODIUM CANTHARIDINATE ON HUMAN HEPATOMA HEPG2 CELLS
Backgroud: Cantharidin, and its derivatives can not only inhibit the proliferation of tumor cells, but can also induce tumor cell apoptosis. It shows cantharidin exhibits a wide range of reactivity in anticancer. The objective of this paper was to study the inhibitory effect of sodium cantharidinate on human hepatoma HepG2 cells.
Materials and Methods: MTT assay was used to detect the proliferation of HepG2 cells, and immunohisto-chemical method was used to detect the change in VEGF, protein level, and to determine the inhibitory effect of sodium cantharidinate on human hepatoma HepG2 cells.
Results: As results, sodium cantharidinate significantly inhibited the growth of HepG2 cells in a time-and dose-dependent manner.
Conclusion: We conclude that sodium cantharidinate has an inhibitory effect on human hepatoma HepG2 cells
Life fingerprints of nuclear reactions in the body of animals
Nuclear reactions are a very important natural phenomenon in the universe. On the earth, cosmic rays constantly cause nuclear reactions. High energy beams created by medical devices also induce nuclear reactions in the human body. The biological role of these nuclear reactions is unknown. Here we show that the in vivo biological systems are exquisite and sophisticated by nature in influence on nuclear reactions and in resistance to radical damage in the body of live animals. In this study, photonuclear reactions in the body of live or dead animals were induced with 50-MeV irradiation. Tissue nuclear reactions were detected by positron emission tomography (PET) imaging of the induced beta+ activity. We found the unique tissue "fingerprints" of beta+ (the tremendous difference in beta+ activities and tissue distribution patterns among the individuals) are imprinted in all live animals. Within any individual, the tissue "fingerprints" of 15O and 11C are also very different. When the animal dies, the tissue "fingerprints" are lost. The biochemical, rather than physical, mechanisms could play a critical role in the phenomenon of tissue "fingerprints". Radiolytic radical attack caused millions-fold increases in 15O and 11C activities via different biochemical mechanisms, i.e. radical-mediated hydroxylation and peroxidation respectively, and more importantly the bio-molecular functions (such as the chemical reactivity and the solvent accessibility to radicals). In practice biologically for example, radical attack can therefore be imaged in vivo in live animals and humans using PET for life science research, disease prevention, and personalized radiation therapy based on an individual's bio-molecular response to ionizing radiation
Zaštitno djelovanje vlaknastoga tkiva u hrani od neurobihevioralnih poremećaja uzrokovanih manganom u štakora
We tested the hypothesis that dietary fi bre (DF) has protective effects against manganese (Mn)-induced neurotoxicity. Forty-eight one-month old Sprague-Dawley rats were randomly divided into six groups: control, 16 % DF, Mn (50 mg kg-1 body weight), Mn+ 4 % DF, Mn+ 8 % DF, and Mn+ 16 % DF. After oral administration of Mn (as MnCl2) by intragastric tube during one month, we determined Mn concentrations in the blood, liver, cerebral cortex, and stool and tested neurobehavioral functions. Administration of Mn was associated with increased Mn concentration in the blood, liver, and cerebral cortex and increased Mn excretion in the stool. Aberrations in neurobehavioral performance included increases in escape latency and number of errors and decrease in step-down latency. Irrespective of the applied dose, the addition of DF in forage decreased tissue Mn concentrations and increased Mn excretion rate in the stool by 20 % to 35 %. All neurobehavioral aberrations were also improved. Our fi ndings show that oral exposure to Mn may cause neurobehavioral abnormalities in adult rats that could be efficiently alleviated by concomitant supplementation of DF in animal feed.U ovome je ispitivanju testirana hipoteza da vlaknasto tkivo u hrani (DF - od engl. dietary fi bre) štiti od neurotoksičnoga djelovanja mangana (Mn). Četrdeset i osam Sprague-Dawley štakora nasumce je raspoređeno u šest skupina: kontrolnu, skupinu koja je primala 16 %-tni udio vlaknastoga tkiva u hrani (DF 16 %), Mn (50 mg kg-1 tjelesne težine), Mn+DF 4 %, Mn+DF 8 % i Mn+DF 16 %. Nakon peroralne primjene Mn (u obliku MnCl2) kroz gastričnu cjevčicu u trajanju od mjesec dana, utvrdili smo koncentracije Mn u krvi, jetri, moždanoj kori i stolici te napravili pretrage neurobihevioralnih funkcija. Primjena Mn bila je povezana s povišenom koncentracijom Mn u krvi, jetri i moždanoj kori te s povećanim uklanjanjem stolicom. Poremećaji neurobihejvioralne funkcije obuhvaćali su produljeno vrijeme bijega te veći broj pogrešaka i skraćeno vrijeme silaska s platforme. Bez obzira na primijenjenu dozu, dodavanje vlaknastoga tkiva u hranu dovelo je do pada koncentracija Mn i njegova povećanog uklanjanja stolicom za 20 % do 35 %. Također su se popravili nalazi svih neurobihejvioralnih testova. Naši nalazi pokazuju da izlaganje Mn oralnim putom može dovesti do neurobihejvioralnih poremećaja u odraslih štakora, koji se mogu uspješno ublažiti istodobnim dodavanjem vlaknastoga tkiva u hranu
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