The Effect of Sweeteners on Perceived Viscosity

Two different sweeteners, sucrose and aspartame, were matchedin perceived sweetness intensity. These solutions were thickenedwith carboxymethylcellulose to six different viscosity levels.Sucrose and aspartame appeared to decrease perceived viscosityof the solutions at a specific sweetener concentration, at allviscosity levels. However, in a second similar experiment withthree viscosity levels and seven sucrose concentrations no effectof sucrose concentration on perceived viscosity was found. Reasonsfor these conflicting results are discussed. No definite conclusionsabout the effect of sweeteners on perceived viscosity can asyet be drawn. Chem. Senses 20: 441–450, 1995.     

Effect of Nasal Dilators on Perceived Odor Intensity

Subjects wearing nasal dilators rated olfactory stimuli as beingmore intense compared with ratings done without nasal expansion.The results support a perceptual constancy model in olfaction.Chem. Senses 22: 177–180, 1997. ¹Present address: Biology Department, St Lawrence UniversityCanton, NY 13617, USA²Present address: PO Box 802, Drew University, Madison, NJ 07940,USA     

Direct and Indirect Effects of Five Factor Personality and Gender on Depressive Symptoms Mediated by Perceived Stress

This study was designed to investigate associations among five factor personality traits, perceived stress, and depressive symptoms and to examine the roles of personality and perceived stress in the relationship between gender and depressive symptoms. The participants (N = 3,950) were part of a cohort study for health screening and examination at the Kangbuk Samsung Hospital. Personality was measured with the Revised NEO Personality Inventory (NEO-PI-R). Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D). Perceived stress level was evaluated with a self-reported stress questionnaire developed for the Korea National Health and Nutrition Examination Survey. A higher degree of neuroticism and lower degrees of extraversion, agreeableness, and conscientiousness were significantly associated with greater perceived stress and depressive symptoms. Neuroticism and extraversion had significant direct and indirect effects (via stress as a mediator) on depressive symptoms in both genders. Agreeableness and conscientiousness had indirect effects on depression symptoms in both genders. Multiple mediation models were used to examine the mediational roles of each personality factor and perceived stress in the link between gender and depressive symptoms. Four of the personality factors (except openness) were significant mediators, along with stress, on the relationship between gender and depressive symptoms. Our findings suggest that the links between personality factors and depressive symptoms are mediated by perceived stress. As such, personality is an important factor to consider when examining the link between gender and depression.     

Effects of Vitamin A on In Vitro Maturation of Pre-Pubertal Mouse Spermatogonial Stem Cells

Testicular tissue cryopreservation is the only potential option for fertility preservation in pre-pubertal boys exposed to gonadotoxic treatment. Completion of spermatogenesis after in vitro maturation is one of the future uses of harvested testicular tissue. The purpose of the current study was to evaluate the effects of vitamin A on in vitro maturation of fresh and frozen-thawed mouse pre-pubertal spermatogonial stem cells in an organ culture system. Pre-pubertal CD1 mouse fresh testes were cultured for 7 (D7), 9 (D9) and 11 (D11) days using an organ culture system. Basal medium was supplemented with different concentrations of retinol (Re) or retinoic acid (RA) alone or in combination. Seminiferous tubule morphology (tubule diameter, intra-tubular cell type), intra-tubular cell death and proliferation (PCNA antibody) and testosterone level were assessed at D7, D9 and D11. Pre-pubertal mouse testicular tissue were frozen after a soaking temperature performed at -7°C, -8°C or -9°C and after thawing, were cultured for 9 days, using the culture medium preserving the best fresh tissue functionality. Retinoic acid at 10^-6M and retinol at 3.3.10^-7M, as well as retinol 10^-6M are favourable for seminiferous tubule growth, maintenance of intra-tubular cell proliferation and germ cell differentiation of fresh pre-pubertal mouse spermatogonia. Structural and functional integrity of frozen-thawed testicular tissue appeared to be well-preserved after soaking temperature at -8°C, after 9 days of organotypic culture using 10^-6M retinol. RA and Re can control in vitro germ cell proliferation and differentiation. Re at a concentration of 10^-6M maintains intra-tubular cell proliferation and the ability of spermatogonia to initiate spermatogenesis in fresh and frozen pre-pubertal mouse testicular tissue using a soaking temperature at -8°C. Our data suggested a possible human application for in vitro maturation of cryopreserved pre-pubertal testicular tissue.     

Geometry Effect on Plasmon Frequency in Triangular Nanoprism

Plasmonics - Surface plasmon resonance is one of the important properties of noble metals which can be controlled by shape, size, and composition. This feature helps scientists to detect individual...     

Neural Resolution of Formant Frequencies in the Primary Auditory Cortex of Rats

Pulse-resonance sounds play an important role in animal communication and auditory object recognition, yet very little is known about the cortical representation of this class of sounds. In this study we shine light on one simple aspect: how well does the firing rate of cortical neurons resolve resonant (“formant”) frequencies of vowel-like pulse-resonance sounds. We recorded neural responses in the primary auditory cortex (A1) of anesthetized rats to two-formant pulse-resonance sounds, and estimated their formant resolving power using a statistical kernel smoothing method which takes into account the natural variability of cortical responses. While formant-tuning functions were diverse in structure across different penetrations, most were sensitive to changes in formant frequency, with a frequency resolution comparable to that reported for rat cochlear filters.     

The Effect of Furnishing on Perceived Spatial Dimensions and Spaciousness of Interior Space

Despite the ubiquity of interior space design, there is virtually no scientific research on the influence of furnishing on the perception of interior space. We conducted two experiments in which observers were asked to estimate the spatial dimensions (size of the room dimensions in meters and centimeters) and to judge subjective spaciousness of various rooms. Experiment 1 used true-to-scale model rooms with a square surface area. Furnishing affected both the perceived height and the spaciousness judgments. The furnished room was perceived as higher but less spacious. In Experiment 2, rooms with different square surface areas and constant physical height were presented in virtual reality. Furnishing affected neither the perceived spatial dimensions nor the perceived spaciousness. Possible reasons for this discrepancy, such as the influence of the presentation medium, are discussed. Moreover, our results suggest a compression of perceived height and depth with decreasing surface area of the room.     

Influence of Pregnancy Spacing on Outcome of Pregnancy

To assess the significance of the length of time between two pregnancies on the outcome of the second we used information collected by the British Perinatal Mortality Survey of 1958. From questionnaires on the 16,994 singleton births in the first week of March 1958 and the 7,117 singleton stillbirths and neonatal deaths in March, April, and May 1958 we abstracted information on the date and outcome of any preceding pregnancy. The interpregnancy interval was taken as the length of time between this preceding pregnancy and the last menstrual period before the index pregnancy. The most important factors influencing pregnancy spacing were outcome of the preceding delivery, social class, and maternal age. When these variables had been taken into account we found that the length of interpregnancy interval had little effect on stillbirth rates. High neonatal death rates, however, occurred when interpregnancy intervals were less than six months (P <0·005), though longer intervals had no significant effects.     

Effect of Orthostasis on Endothelial Function: A Gender Comparative Study

As the vascular endothelium has multiple functions, including regulation of vascular tone, it may play a role in the pathophysiology of orthostatic intolerance. We investigated the effect of orthostasis on endothelial function using EndoPAT®, a non-invasive and user-independent method, and across gender. As sex steroid hormones are known to affect endothelial function, this study examined the potential effect of these hormones on the endothelial response to orthostasis by including females at different phases of the menstrual cycle (follicular and luteal—where the hormone balance differs), and females taking an oral contraceptive. A total of 31 subjects took part in this study (11 males, 11 females having normal menstrual cycles and 9 females taking oral contraceptive). Each subject made two visits for testing; in the case of females having normal menstrual cycles the first session was conducted either 1–7 (follicular) or 14–21 days (luteal) after the start of menstruation, and the second session two weeks later, i.e., during the other phase, respectively. Endothelial function was assessed at baseline and following a 20-min orthostatic challenge (active standing). The EndoPAT® index increased from 1.71 ± 0.09 (mean ± SEM) at baseline to 2.07 ± 0.09 following orthostasis in females (p<0.001). In males, the index increased from 1.60 ± 0.08 to 1.94 ± 0.13 following orthostasis (p<0.001). There were no significant differences, however, in the endothelial response to orthostasis between females and males, menstrual cycle phases and the usage of oral contraceptive. Our results suggest an increased vasodilatatory endothelial response following orthostasis in both females and males. The effect of gender and sex hormones on the endothelial response to orthostasis appears limited. Further studies are needed to determine the potential role of this post orthostasis endothelial response in the pathophysiology of orthostatic intolerance.     

Gender,Brain-Derived Neurotrophic Factor Val66Met,and Frequency of Methamphetamine Use

BackgroundFrequency of pretreatment methamphetamine (MA) use is an important predictor of outcomes of treatment for MA dependence. Preclinical studies suggest females self-administer more MA than males, but few clinical studies have examined potential sex differences in the frequency of MA use. Estrogen increases expression of brain-derived neurotrophic factor (BDNF), which has effects on MA-induced striatal dopamine release and protects against MA-induced neurotoxicity.ObjectiveWe examined potential effects of sex, the Val66Met polymorphism in BDNF, and their interaction on frequency of MA use among 60 Caucasian MA-dependent volunteers screening for a clinical trial.MethodsData was taken from 60 Caucasian MA-dependent volunteers screening for a clinical trial.ResultsFemales reported significantly more pretreatment days with MA use in the past 30 days than males. There was a significant interaction between sex and BDNF Val66Met, with the highest frequency of MA use among females with Val/Val genotype.ConclusionsThese results, although preliminary, add to the literature documenting sexual dimorphism in response to stimulants, including MA, and suggest a potential biological mechanism involving BDNF that might contribute to these differences. Additional research characterizing the biological basis of altered response to MA among females is warranted.     

Spacing of the -10 and -35 regions in the tac promoter. Effect on its in vivo activity

In the tac promoter (deBoer, H. A., Comstock, L. J., and Vasser, M. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 21-25) the spacing between the -35 and -10 consensus sequences is 16 base pairs. Between these two regions we inserted 1 or 2 base pairs to increase the distance to 17 base pairs (trc promoter) or 18 base pairs (tic promoter). The activities of the three promoters were compared in vivo by fusion to the chloramphenicol acetyltransferase or to the Escherichia coli 4.5 S RNA gene. Both measurements gave consistent results. The trc and tic promoters are on average about 90% and 65% as active as the tac promoter, respectively.     

Effect of Protistan Grazing on the Frequency of Dividing Cells in Bacterioplankton Assemblages

Grazing by phagotrophic flagellates and ciliates is a major source of mortality for bacterioplankton in both marine and freshwater systems. Recent studies have demonstrated a positive relationship between clearance rate and prey size for bacterivorous protists. We tested the idea that, by selectively grazing the larger (more actively growing or dividing) cells in a bacterial assemblage, protists control bacterial standing stock abundances by directly cropping bacterial production. Samples of estuarine water were passed through 0.8-μm-pore-size filters (bacteria only) or 20-μm-mesh screens (bacteria and bacterivorous protists) and placed in dialysis tubing suspended in 7 liters of unfiltered water. Changes in total bacterial biovolume per milliliter (bacterial biomass), frequency of dividing cells (FDC), and average per cell biovolume were followed over a period of 24 h. In three experiments, the FDC increased more rapidly and attained higher values in water passed through 0.8-μm-pore-size filters (average, 5.1 to 8.9%; maximum, 15.5%) compared with FDC values in water passed through 20-μm-mesh screens (average, 2.7 to 5.3%; maximum, 6.7%). Increases in bacterial biomass per milliliter lagged behind increases in FDC by about 4 to 6 h. Grazed bacterial assemblages were characterized by lower total biomasses and smaller average cell sizes compared with those of cells in nongrazed assemblages. We conclude that bacterivorous protists control bacterial standing stock abundances partly by preferentially removing dividing cells. Selective grazing of the more actively growing cells may also explain, in part, the ability of slow-growing cells to persist in bacterioplankton assemblages.     

The Effect of Oxygen on the Frequency of Somatic Recombination in DROSOPHILA MELANOGASTER

The influence of oxygen on the frequency of somatic recombination in the yellow singed system on the X chromosome of Drosophila melanogaster was studied under a variety of experimental conditions. Flies raised from egg to adult in atmospheres containing 70-90% oxygen were found to have significantly more mosaic spots on their abdominal tergites than were observed in flies which developed in air. First instar larvae X-rayed in from 0 to 100% oxygen demonstrated the existence of an oxygen effect for somatic recombination in the cells which form the abdominal hypoderm. The mosaic spot counts, beginning with the lowest numbers which were found in flies X-rayed in nitrogen, increased rapidly with rising oxygen tensions until the percentage in air was reached, then leveled off at the higher concentrations. Post-treatment with nitrogen of larvae X-rayed in air or oxygen created a substantially higher number of mosaic spots than were found when larvae, after being similarly irradiated, were instead placed into air or oxygen.     

H22腹水型肝癌荷瘤小鼠耐受性的性别差异

目的:观察性别对小鼠H22腹水型肝癌生长情况的影响,研究不同性别动物对肝癌耐受性的差异。方法:取30只8周龄昆明鼠,雌雄各半,随机分为四组,实验组每组10只,对照组每组5只,腹腔接种小鼠H22肝癌细胞,建立小鼠H22腹水型肝癌模型。每天测量小鼠体重并记录生存时间,直至实验组小鼠全部死亡,比较性别因素对小鼠H22腹水型肝癌的生存期是否存在差异。结果:小鼠接种瘤细胞后,逐渐产生腹水,体重增加。雌性小鼠的体重增加比雄性小鼠显著,P=0.049。雄性小鼠生存后期体重出现下降,呈明显恶液质状态。雌性小鼠的体重、腹水增加虽然较雄性动物明显,但生存期却并不少于雄性鼠,反而比雄性小鼠略长,P=0.1567。结论:性别对小鼠H22腹水型肝癌的生长有一定的差异,雌性小鼠的耐受性优于雄性小鼠。