Berberine Prolongs Life Span and Stimulates Locomotor Activity of <i>Drosophila melanogaster</i>

Drosophila melanogaster mutants with deficient kynurenine (KYN) formation from tryptophan (TRP) have longer life span than wild type flies. Administration of alpha-methyl-TRP and 5-methyl-TRY, the inhibitors of TRP-KYN metabolism, prolonged life span in wild-type flies. Both inhibitors are not available for human use. Berberine, an isoquinoline alkaloid isolated from berberis aristata is known as the herb widely used in traditional Chinese and Indian medicine. Berberin is a strong inhibitor of the enzyme catalyzing TRP conversion into KYN. Considering this particular feature we investigated the effect of berberine on life-and health-span in wild-type Drosophila melanogaster. The results of our study showed that Berberine extended mean, median and maximum life span of female flies. Berberine did not affect the number of pupae of filial generation and decreased their lethality. Berberine increased locomotor activity (vertical climbing). The results of the study suggest that berberine prolongs life- and improves health-span of Drosophila melanogaster. Berberine might be a candidate drug for prevention and treatment of aging and aging-associated medical and psychiatric disorders.

Spermatozoid life-span of two brown seaweeds, Saccharina japonica and Undaria pinnatifida, as measured by fertilization efficiency

During sexual reproduction of seaweeds, spermatozoid (sperm) discharge is triggered by chemical messengers (pheromones) released by the female gametes. The chemotactic ability of the sperm ensures fertilization success. Using unialgal male and female gametophyte material under designated standard gametogenesis testing (SGT) conditions, the potential life-span of the sperm of two seaweeds, Saccharina japonica and Undaria pinnatifida, was assessed by their ability to fertilize eggs. Results show that within 20-30 min after being discharged, sperm of both species could complete fertilization without an apparent decline in fertilization rate. Although fertilization rate 60-120 min after sperm discharge dropped significantly in both species, some sperm were viable enough to fertilize the eggs. In S.japonica, at 12°C, some sperm were able to fertilize eggs up to 12 h after discharge. In both species, egg discharge rates (EDR) in the male and female mixed positive controls were significantly higher than those of all the sperm-testing groups. Doubling the seeded male gametophytes of S. japonica in the SGT tests significantly increased the EDR, further confirming the effect of the presence of the male on the female in terms of facilitating egg discharge from oogonia.

Effects of salinity on egg and fecal pellet production, development and survival, adult sex ratio and total life span in the calanoid copepod, A cartia tonsa:a laboratory study

The ef fects of salinity on the copepod, A cartia tonsa in terms of daily egg production rate(EPR), hatching success, fecal pellet production rate(FPR), naupliar development time and survival, sex ratio, and total life span were determined in laboratory conditions through three experiments. In experiment 1, EPR, hatching success, and FPR of individual females were monitored at salinities of 13, 20, 35 and 45 during short-periods(seven consecutive days). Results show EPR was aff ected by salinity with the highest outputs recorded at 20 and 35, respectively, which were considerably higher than those at 13 and 45. Mean FPR was also higher in 35 and 20. In experiment 2, the same parameters were evaluated over total life span of females(long-term study). The best EPR and FPR were observed in 35, which was statistically higher than at 13 and 20. In experiment 3, survival rates of early nauplii until adult stage were lowest at a salinity of 13. The development time increased with increasing of salinity. Female percentage clearly decreased with increasing salinity. Higher female percentages(56.7% and 52.2%, respectively) were signifi cantly observed at two salinities of 13 and 20 compared to that at 35(25%). Total longevity of females was not af fected by salinity increment. Based on our results, for mass culture we recommend that a salinity of 35 be adopted due to higher reproductive performances, better feeding, and faster development of A. tonsa.

SECONDARY CRITICAL EXPONENT AND LIFE SPAN FOR A DOUBLY SINGULAR PARABOLIC EQUATION WITH A WEIGHTED SOURCE

This paper deals with the Cauchy problem for a doubly singular parabolic equation with a weighted source ut=div｜u｜p-2um）＋｜x｜α uq ,（x,t）∈RN×（0,t）,where N ≥ 1, 1 〈 p 〈 2, m 〉 max（0,3 -p/N} satisfying 2 〈 p＋m 〈 3, q 〉 1, and（α 〉 N（3 - p - m） - p. We give the secondary critical exponent on the decay asymptotic behavior of an initial value at infinity for the existence and non-existence of global solutions of the Cauchy problem. Moreover, the life span of solutions is also studied.

Premature losses of leaf area in response to drought and insect herbivory through a leaf lifespan gradient

Implications of the differences in leaf life span are still subject to debate in the field of ecophysiology.Since leaf traits associated with these differences may be decisive for determining the distribution of tree species,this topic is particularly relevant in the context of climate change.This study analyzes the effects of the differences in leaf life span on premature losses of leaf area owing to insect herbivory and to abiotic stress.Loss of leaf area may be an important determinant of total leaf carbon assimilation.Seven Mediterranean tree species,distributed on four sites with different climates were studied.The species exhibited strong differences in leaf life span and in leaf traits,especially leaf mass per unit area.Premature leaf area losses were estimated in response to insect herbivory and summer drought over two years.The results revealed that,despite having older leaf cohorts with more damage,species with longer leaf duration had lower area lost to herbivores and less damage due to accelerated senescence during the summer drought.With respect to the predicted increase in water stress,deciduous species are at a disadvantage due to their high premature loss of leaf area and thus loss of photosynthetic capacity.

Life-span of classical solutions for one-dimensional hydromagnetic flow

The paper concerns Cauchy,problem for one-dimensional hydromagnetic dynamics with dissipative terms. When the dissipation coefficient is equal to zero it is shown that the smooth solutions develop shocks in the finite time if the initial amounts of entropy and magnetic field are smaller than those of sound waves; when it is larger than zero, and the initial amounts of entropyI this dissipation coefficient and the magnetic field in each period are smaller than those of sound Waves, then the smooth solutions blow up in the finite time. Moreover, the life-span of the smooth solution is given.

LIFE-SPAN OF CLASSICAL SOLUTIONS TO HYPERBOLIC GEOMETRY FLOW EQUATION IN SEVERAL SPACE DIMENSIONS

In this article, we investigate the lower bound of life-span of classical solutions of the hyperbolic geometry flow equations in several space dimensions with ＂small＂ initial data. We first present some estimates on solutions of linear wave equations in several space variables. Then, we derive a lower bound of the life-span of the classical solutions to the equations with ＂small＂ initial data.

Existence and Life Span of Periodic Solutions for the First Order Quasilinear Hyperbolic Equations

In this paper the authors consider Cauchy problem of first order quasilinear hyperbolic and prove that existence of its periodic solutions and estimates of life span of solutions. This results reveals the relationship of dissipation and smoothness of periodic solutions.

Dietary <i>γ</i>-Aminobutyric Acid Shortens the Life Span of Stroke-Prone Spontaneously Hypertensive Rats

Dietary γ-amino butyric acid (GABA) has been suggested to decrease systolic blood pressure. This study aimed to ex-amine the effects of dietary GABA on the life span of stroke-prone spontaneously hypertensive rats (SHRSPs). In this study, life span was determined for SHRSPs provided 1% NaCl solution or 0.01% GABA in 1% NaCl solution as drinking water. The life span of the GABA-fed group (76.3 ± 1.65 days) was significantly shorter than that of the control group (81.6 ± 0.88 days). The results of this study may not be applicable to humans. Future studies will be necessary to elucidate the mechanism underlying this phenomenon.

Performance Survey of PVC Insulation of LC/Gecamines Electrical Cables Subjected to Ageing and Its Life Span Evaluation

Considering the insulators ageing in a mixture of PVC and dye, set following operating conditions and time to ensure proper operation and perfect safety of industrial installations using insulated conductors. The results showed that the insulation carried out by the L.C main office was a good quality (on thermal aspect), because the resistance of the insulation is so high (i.e. 3940 Mega Ohms under normal conditions). The results showed a lifespan of 50 years at a temperature of 40°C (close to ambient temperature), plus minus 33 years at a temperature of 70°C;plus minus 22 years at a temperature of 100°C and 12 years at a temperature of 160°C. Furthermore, information on chemical attack, the results showed that PVC cables have poor resistance to sulfuric acid attack (having a pH of 1.5 and a density of 1.84 g/cm3). LC/Gecamines is able to produce locally a good quality of electrical cables.

Increased life-span of Drosophila melanogaster by Flavonoids from Scutellariabaicalensis Georgi induced by hydrogen peroxide

目的：探讨黄芩中黄酮类化合物在过氧化氢（H2O2）诱导黑腹果蝇模型中的作用及机制.方法：采用H2O2诱导黑腹果蝇衰老模型,研究黄芩中黄酮化合物的作用.其次,研究了黄芩素和汉黄芩素对mRNA表达的影响.结果：黄芩素和汉黄芩素能够通过增加超氧化物歧化酶（SOD）,过氧化氢酶（CAT）和玫瑰红（RY）mRNA的表达,延长H2O2诱导果蝇老化模型的寿命.结论：黄芩素和汉黄芩素可能通过上调SOD,CAT和RYmRNA的表达,延长H2O2诱导的果蝇老化模型的寿命.

Analysis of Safe Span Length and Fatigue Life of Submarine Pipelines

Owing to the complex environmental conditions, suspension could induce complicated forces on submarine pipelines and even cause vortex-induced vibration, resulting in fatigue damage of pipelines. Through aiming at the 28-inch submarine pipeline in the East China Sea, the pipeline was segmented according to the similarity, considering the factors of pipe assembly, typhoon, current, wave and seabed topography. The effects of span length on natural frequency in each section of submarine pipeline were analyzed by finite element model. The maximum safe span length allowed by each pipeline section was verified by fatigue cumulative damage theory, and the fatigue life of each pipeline section were predicted. The results showed that each order natural frequency of the pipeline decreased with the increase of span length. The calculated results of empirical formulas were much smaller than those of the FEM analysis. The increase of the gap between the suspended pipeline and the seabed was beneficial to enhance the fatigue life of the suspended pipeline.

基于CLD模型的风电叶片延寿区间估计

为确定在役风电叶片到达设计寿命后能否延寿继续使用,提出一种基于恒幅寿命图模型的延寿区间计算方法。首先,分析叶片在运行工况下的载荷状况,采用应力-寿命(S-N)曲线分析弯矩作用下的疲劳寿命,进而定义弯矩-寿命(M-N)曲线。根据M-N曲线和CLD模型的映射关系建立延寿估计的CLD模型。基于延寿估计的CLD模型计算待退役叶片已累积的疲劳损伤,并从疲劳损伤估计可持续延寿的时间。最后,以某型叶片为例应用该方法进行延寿区间估计。

不同雌雄成虫密度及性比对红彩瑞猎蝽繁殖力和寿命的影响

在室内条件[温度(28±1)℃,相对湿度70%±7%,光照周期16 h(L)∶8 h(D)]下,测定不同雌雄成虫密度(雌∶雄=1∶1、2∶2、3∶3和4∶4)和不同性比(头/盒)(雌∶雄=1∶0、1∶2、1∶3、1∶4、2∶1、3∶1、3∶2和4∶1)对捕食性天敌红彩瑞猎蝽(Rhynocoris fuscipes Fabricius)产卵前期、产卵期、产卵量、孵化率、寿命和子代雌雄性比的影响。结果表明,红彩瑞猎蝽成虫繁殖存在孤雌生殖现象,可产下有效卵。不同雌雄成虫密度和雌雄性比对红彩瑞猎蝽产卵前期和卵孵化率的影响不明显,对产卵期、产卵量、子代雌雄性比和雌雄成虫寿命有显著影响,总产卵量随着配比中雌成虫密度的增加而增加,但是每雌产卵量和孵出若虫数量逐渐减少;雌成虫、雄成虫平均寿命均随着雌雄成虫密度的增加而减小。其中雌雄性比为2∶1的处理平均产卵期最长(39.5 d),平均每雌产卵量最高(136.40粒),每雌孵出若虫数最多(130.30头)。在交配过程中,红彩瑞猎蝽成虫密度过大会出现种内互残现象,基于研究结果中各项繁殖力和寿命参数结果,雌雄性比2∶1是人工饲养红彩瑞猎蝽成虫繁殖的较佳密度和性比。

氧化锌避雷器故障状态指示器试验方法研究

氧化锌阀片在冲击电流的作用下,短时间内有大量的电流流过,阀片吸收冲击能量后的升温过程可近似看作绝热温升,因而冲击老化的机理主要是热老化。冲击老化会给阀片造成较大的损坏,多次冲击对阀片老化造成累积效应。资料中显示阀片在4/10μs波形、100 kA冲击电流作用后,其在直流1 mA电压下的功率损耗可增加20%。试验发现,用于线路避雷器标称放电电流为10 kA的ZnO阀片在经过18次20 kA、8/20s电流的冲击后,阀片功率损耗为初始功率损耗的2倍,根据功率损耗密度分析法,可认为此时阀片已接近其寿命终点。对于带间隙线路避雷器,在正常运行时不承受工频电压,不存在泄漏电流,可以记录避雷器遭受冲击大电流的次数,用于反映避雷器的寿命检测,达到设定值会有告警指示。

地中海贫血合并自身或同种异体抗体的研究进展

地中海贫血是一种严重的进行性贫血,需要规范化输血和祛铁才能达到预期寿命。输血最重要的并发症之一是同种异体免疫和自身免疫,增加了配血的难度,也降低了输血的效果。本文综述了地中海贫血合并自身免疫性溶血性贫血(AIHA)的发生率、诊断及临床特点、输血及药物治疗现状,并对红细胞寿命(RBCS)检测的方法及在地中海贫血合并AIHA中的应用可行性进行了分析。

冷却速度对Thermo-Span合金组织和持久性能的影响

采用扫描电镜(SEM)、透射电镜(TEM)研究了固溶冷却速度对改型低膨胀Thermo-Span合金组织和持久性能的影响。结果表明:固溶冷却速度由空冷变为水冷,其它热处理条件不变,含0.05%B合金晶内析出γ′相的数量未见明显增多,而颗粒的尺寸变小,形态没有改变,晶界析出增多。合金650℃,600MPa的光滑持久性能保持较高水平,合金的缺口敏感性消失。

一种新型家用电器寿命试验机的设计与应用

本研究旨在开发一种新型的家用电器寿命试验机,以解决现有试验方法的局限性和不足。通过模拟家用电器在实际使用中的环境和操作条件,该试验机能够更真实、更快速地评估家用电器的性能和寿命。本研究详细介绍了新型试验机的设计原理、结构组成和技术特点,并通过实验验证了其有效性和可靠性。结果表明,该试验机能够准确模拟家用电器的实际使用情况,为制造商提供可靠的产品性能评估数据。本研究对于提升家用电器质量、满足市场需求、推动行业发展和节约资源具有重要意义。

浪涌保护器寿命自监测系统研究

浪涌保护器(SPD)广泛应用于铁路通信信号系统中,可实现对被防护电路瞬时过电压、过电流的钳制和泄放。由于浪涌保护器在使用过程中存在劣化问题,因此开展浪涌保护器寿命自监测系统研究非常必要。该系统由传感器、微控制器、显示和通信等多种功能模块构成,可实现对雷电流和脱扣状态监测,以及CAN通信和NFC通信接口等应用;通过计算劣化核,进而计算寿命值,构建SPD寿命模型;展示了SPD状态显示及报警发布的流程。在SPD中引入雷电流测量机制,基于历次雷电流冲击数据构建的寿命模型,相比于单纯依赖是否脱扣作为寿命判别条件更科学、更准确;相比于使用漏电流进行寿命表征,更具有广泛的适用性。实际应用中的SPD适配了该系统后,可明确感知SPD的状态和寿命值,从而降低劳动强度,提升SPD雷电防护的可靠性。