[A study on the effect evaluation of virtual reality on workplace employees' emotional optimization].

Objective: To explore the effect of emotional optimization of workplace employees in immersive virtual natural environment. Methods: In July 2020, 15 subjects were selected to complete two groups of treadmill walking training experiments in virtual natural environment and daily environment respectively. At the same time, the subjects' skin electrical (EDA) , pulse frequency (Pf) , respiratory frequency (Rf) physiological data and Self-Assessment Manikin (SAM) data before and after walking were collected; the mean value of three dimensions of SAM and the emotion difference before and after the experiment were calculated. The differences of physiological indexes and subjective mood changes of subjects were tested by paired sample t-test. Results: Compared with the daily environment, the ΔEDA, ΔPf and ΔRf of the subjects in the virtual natural environment were all decreased , and the differences were statistically significant (P<0.05). There were statistically significant differences in pleasure and arousal between subjects before and after using the virtual natural environment (P <0.05). Compared with the daily environment, the Δpleasure degree of subjects using the virtual natural environment increased, and the Δarousal degree and Δdominance degree decreased, and the differences were statistically significant (P <0.05). Conclusion: Walking in virtual natural environment can help subjects improve their mood, relax and improve the regulation ability of autonomic nervous system.

[Influence of carrying system on human gait and fatigue].

Objective: To investigate the influence of different variable combinations of the carrying system on gait and muscle fatigue during weight-bearing walking on both shoulders and back, and to optimize daily carrying experience. Methods: From September to December, 2018, 6 male college students were selected as subjects; the electromyographic signal of the anterior tibial muscle and plantar pressure were measured during weight-bearing walking under six different variable combinations of the carrying system (with the three variables of gravity center, single or double shoulders, and waist cushion), and a subjective evaluation test was performed for the degree of fatigue. The electromyographic data and plantar pressure data were processed and compared to evaluate behavior and fatigue. Results: Different variable combinations of the carrying system had significant influence on the degree of fatigue and gait (P<0.05). Both subjective and objective analyses found that the carrying system with different heights of gravity center and single-or double-shoulder carrying mode had great influence on human fatigue and walking gait, while the hardness of waist cushion had little influence. Compared with the other groups, the group with a high gravity center, a double-shoulder carrying mode, and a soft waist cushion had a significantly smaller slope of average electromyographic amplitude, a significantly larger slope of median frequency, and a significantly lower degree of plantar pressure curve disorder. Conclusion: The carrying system with a relatively high gravity center, a double-shoulder carrying mode, and a soft waist cushion can significantly relieve fatigue, with low influence on walking gait.

[Research on the influence factors of the carrying system].

Objective: To investigate surface electromyography signal (sEMG) of the major back muscle group and subjective fatigue assessment under different experimental combinations during walk with weight on both shoulders, as well as the functional status and fatigue property of human muscles. Methods: From October to December, 2017, 10 college students were recruited to participate in shoulder weight-bearing work and walk under the combinations of different shoulder strap widths, weights, and hardness of waist cushion. The subjects were required to complete 12 sets of experiments, with each set lasting for 15 minutes, and the rest time between work was 30 minutes. The sEMG signals of the upper trapezius and the erector spinae were measured during the experiment, and subjective fatigue assessment was performed during rest. The time domain evaluation index (average amplitude, aEMG) , the frequency domain evaluation index (median frequency, MF) , and the data of subjective assessment were processed and analyzed. Results: Weight and shoulder strap width had a significantly effect on fatigue (P<0.01) , and the change in the hardness of waist cushion had no significant effect on fatigue (P>0.05) . There was an interaction effect between weight and shoulder strap width (P<0.01) , and there was no interaction effect between weight, shoulder strap width, and hardness of waist cushion (P>0.05) . For the backpack carrying system, the combination of 10% weight and 50 mm shoulder strap width was the best one for relieving fatigue. The subjective test also showed that subjective feelings of muscle fatigue were associated with the weight and width, which was consistent with sEMG results. Conclusion: The results of this experiment show that the combination of 10% weight and 50 mm shoulder strap width can help to relieve muscle fatigue during walk with weight on both shoulders, and weight-bearing walking is more likely to cause the fatigue of the erector spinae.

[Effect of nutrition quality of breakfast on satiety among young white-collar workers].

Objective: To analyze the effect of breakfast nutrition quality on the satiety among young white-collar workers. Methods: A total of 278 subjects were recruited from two cities, Shenyang and Chongqing, in June 2015. The inclusion criteria: white-collar workers aged 25-45 years involved mainly in office work, who did not experience major changes, and individuals who should follow the study protocol and sign the informed consent form. The study employed a three-phase crossover design trial. Each participant received nutritional-adequate breakfast, nutritional-inadequate breakfast, and no breakfast treatment on the basis of assignment to one of three sequences. The breakfast time was once a week and then changed, all participants underwent the tests for three successive weeks. At last, we compared the effect of participants to consume different nutritional quality on satiety sense and hunger sense. Results: A total of 232 participants completed three successive breakfast intervention studies, the age of participants was (35.2 ± 7.9) years, comprised of 48.7% male (n=113). The numbers of participants of aged 25-35 year-old and aged 36-45 were 118 and 114, respectively. Satiety scores of nutrition-adequate breakfast group, nutrition-inadequate breakfast group and no breakfast group were 63.5±14.7, 53.1±10.2 and 36.4±7.2, respectively (P<0.05). In nutrition-inadequate breakfast group and no breakfast group, male subjects scored significantly higher than female subjects (50.9±10.5 vs 46.6±9.4, 35.2±8.3 vs 31.8±5.4) (P<0.05). And, participants aged 25-35 year-old. got satiety score significantly higher than aged 36-45 (51.3±11.0 vs 45.6±12.1, 34.1±6.8 vs 32.5±7.9), the difference was statistically significant (P<0.05). The scores of hunger in the group of nutrition-adequate breakfast, nutrition-inadequate breakfast and no breakfast were 26.3 ± 8.0, 35.1 ± 11.2 and 57.3 ± 17.0, respectively (P<0.05). Conclusion: The nutrition quality of breakfast affects the satiety of young white-collar workers. The better the nutrition quality of breakfast is, the higher the satiety score and the lower the hunger score become. Compared with women and participants aged 36-45 year-old, men and those aged 25-35 year-old get satiety sense more easily.

Identification of the forensically important beetles Nicrophorus japonicus, Ptomascopus plagiatus and Silpha carinata (Coleoptera: Silphidae) based on 16S rRNA gene in China.

Sarcophagous beetles play an important role in estimating postmortem interval time (PMI) in the later stages decomposition of carcasses. However, the morphological similarity of beetles usually poses a challenge for forensic scientists within their routine work. As a supplementary to traditional morphological method, molecular genetics identification is simple and time-saving. A molecular identification method involving a 288-bp segment of the 16S ribosomal RNA (16S rRNA) gene from 15 beetles of Silphidae (Coleoptera), collected from 5 locations in 4 Chinese provinces, was evaluated. Phenogram analysis of the sequenced segments by the unweighted pairgroup method analysis (UPGMA) method showed that all specimens were properly assigned into four species with strong similarity, which indicated the possibility of separation congeneric species with the short 16S rRNA fragment. These results will be instrumental for implementation of the Chinese database of forensically relevant beetles.

Identification of the forensically important beetles Nicrophorus japonicus, Ptomascopus plagiatus and Silpha carinata (Coleoptera: Silphidae) based on 16S rRNA gene in China

Sarcophagous beetles play an important role in estimating postmortem interval time (PMI) in the later stages decomposition of carcasses. However, the morphological similarity of beetles usually poses a challenge for forensic scientists within their routine work. As a supplementary to traditional morphological method, molecular genetics identification is simple and time-saving. A molecular identification method involving a 288-bp segment of the 16S ribosomal RNA (16S rRNA) gene from 15 beetles of Silphidae (Coleoptera), collected from 5 locations in 4 Chinese provinces, was evaluated. Phenogram analysis of the sequenced segments by the unweighted pairgroup method analysis (UPGMA) method showed that all specimens were properly assigned into four species with strong similarity, which indicated the possibility of separation congeneric species with the short 16S rRNA fragment. These results will be instrumental for implementation of the Chinese database of forensically relevant beetles

Molecular characters and morphological genetics of CAL gene in Chinese cabbage.

BcpCAL, the homologous gene of CAL, was isolated from Chinese cabbage. Unlike BobCAL of cauliflower, BcpCAL did not hold the terminating mutation in the fifth exon. After crosses of cauliflower with Chinese cabbage, the resultant hybrids failed to form curd, which implicates the genetic complement of BcpCAL to the mutated BobCAL in the function of curd formation. One of CAL gene isolated from the hybrid apparently comes from the female parent (Chinese cabbage) even though there are a few of the bases substituted and deleted. The result offers the molecular and genetic evidences for the study of biological function of CAL in morphological genetics of curd.

[Effects of IAA and stimulated microgravity on formation of adventitious roots of Chinese cabbage].

Under the induction of indole-3-acetic acid (IAA), adventitious roots were differentiated on hypocotyl segments derived from seedlings of Chinese cabbage (Brassica campestris spp. pekinensis). IAA at concentration of 0.4-1.0 mg/L in solid MS medium incited many adventitious roots on hypocotyl segments. The earliest anatomic changes were observed on cut surface of hypocotyl segments under optical microscope 24 hours after IAA treatment: cytoplasmic and nuclear density became higher in a few of parenchytmatous cells adjacent to phloem in tissue of pericycle, followed by cell divisions. Lately, the dividing cells expanded and developed into root primordium from which root cap was differentiated. After five days, most roots protruded through hypocotyl cortex and appeared just below the cut surface. The rooting capacity of the segments derived from three regions of each hypocotyl was different. High level of IAA modified the polarity of root formation on segment inserted upside down and sucrose increased the function of IAA. Additionally, microgravity did not significantly change the rooting polarity under the condition of stimulated microgravity, but it increased the competence of explants to IAA treatment. The results presented here provided an experimental system for further investigation of molecular events associated with adventitious root initiation.

Absence of p53 gene mutations in rat colon carcinomas induced through the synergistic interaction between methylazoxymethanol and X-irradiation.

p53 is one the most frequently mutated genes found in human colonic tumors. Because colonic neoplasms induced in rats by certain chemical carcinogens are similar to human colonic tumors in their histological features and proliferation characteristics, the rat has been used as an experimental model to study the pathogenesis of colon cancer. However, p53 mutations were not detected in the chemically induced colonic tumors analyzed for p53 mutations. X-irradiation has also been shown to induce colonic neoplasms in rats that resemble human colonic tumors histopathologically. Because the incidence of colonic tumors induced by methylazoxymethanol (MAM) in rats was shown to be enhanced by X-irradiation, we immunohistochemically analyzed these colonic carcinomas for the presence of p53 gene mutations. The immunohistochemical analyses clearly showed the absence of nuclear immunoreactivity in all ten tumors examined. The results from the present study indicate that point mutations in p53, at least in the coding region, are not involved in the development of colon cancer induced by the combination of MAM and X-irradiation. Our observations, together with the data from previous studies, further suggest that rat colon carcinogenesis, unlike human colon cancer, may not involve p53 mutation as an obligatory event.

A rapid dual organ rat carcinogenesis bioassay for evaluating the chemoprevention of breast and colon cancer.

In this study we evaluated the effect of dietary administration of a high fat, low fiber diet (HRD) with or without 2% phytic acid (PA) on the development of mammary cancer and/or colon cancer in rats exposed to methylnitrosourea (MNU), azoxymethane (AOM) or MNU + AOM. The rats were fed a HRD alone or a HRD + 2% PA. At the end of week 2, the rats were given either a s.c. injection of MNU (50 mg/kg body wt) or one of normal saline (vehicle). At the end of weeks 3 and 4, the rats were given either a s.c. injection of AOM (15 mg/kg body wt per week) or one of normal saline (vehicle). Nine weeks after the injection of MNU or saline, 10 rats from each group were sacrificed and the mammary tumor incidence and the number of colonic aberrant crypt foci (ACF) were compared between different groups. The administration of different diets was continued for an additional 21 weeks and the mammary tumor and colon tumor incidence between different groups were compared. Results showed that rats injected with MNU alone did not develop ACF or colon tumors while those injected with AOM alone did not develop mammary tumors. Linear regression analysis of the number of ACF at 11 weeks versus colonic tumor incidence at 32 weeks, and the linear regression analysis of mammary tumor incidence at 11 weeks versus mammary tumor incidence at 32 weeks, both showed good linear correlation. These results demonstrate the potential value of the short term dual organ carcinogenesis bioassay for screening chemopreventive agents for their relative ability to inhibit the development of mammary cancer and/or colon cancer while on high risk diet.

The effect of dietary fat on the promotion of mammary and colon cancer in a dual-organ rat carcinogenesis model.

Female Sprague-Dawley rats (n = 270) were randomly divided into nine subgroups (30 rats/group) and fed diets with fat contents ranging from 5% to 45% of total energy, in which fat was isocalorically substituted for carbohydrates. At Week 3, the rats were given a single injection of methylnitrosourea (MNU, 50 mg/kg body wt). At Weeks 4 and 5, rats were given an injection of azoxymethane (AOM, 15 mg/kg body wt sc). The rats were maintained on their respective experimental diets until they were sacrificed. Nine weeks after the injection of MNU, 10 rats from each group were killed and their mammary tissue was examined for tumors and their colons for aberrant crypt foci (ACF) formation. The results showed no significant increase in the number of colonic ACF or mammary tumors at 11 weeks among individual groups consuming 5-25% energy from fat or among groups consuming 30-45% energy from fat. Data analysis indicated that the effects of the two diets (5-25% energy from fat and 30-45% energy from fat) on ACF formation as well mammary tumor development were statistically different. Continuation of the diets for 32 weeks led to the development of colonic and mammary tumors. Analysis of the combined group tumor incidence data clearly showed that the colonic and mammary tumor incidence in groups fed 30-45% of energy from fat was significantly higher than that observed among groups fed 5-25% of energy from fat. Linear regression analysis of the colonic ACF at 11 weeks, colonic tumor incidence at 32 weeks, and mammary tumor incidence at 11 and 32 weeks showed good linear correlation, demonstrating the potential value of ACF and mammary tumors at 11 weeks for evaluating the carcinogenic risk associated with different diets. The main conclusion of the experiment is that the incidence of colon and mammary cancers increased rapidly when the dietary levels of fat were increased from 15% to 30% of calories and that there was no significant influence on the colon and mammary cancer risk beyond 30% of calories from fat.

Potential synergism between wheat bran and psyllium: enhanced inhibition of colon cancer.

In this study we compared the influence of high fat (20% w/w) diets that combine low levels of calcium (0.18% w/w) and low (1% w/w), medium (4% w/w) and high (8% w/w) levels of dietary fiber from wheat bran (WB), with high (8% w/w) levels of dietary fiber from psyllium (PS) alone or in various combinations with WB, on the induction of colon tumors in Fischer-344 rats following exposure to azoxymethane (AOM). The rats were fed the experimental diets for 2 weeks, and then were given two s.c. injections of AOM (15 mg/kg body wt./week). Twenty-three weeks following the first injection of AOM, the incidence of colon tumors in the different dietary groups (12 rats/group) was compared. The results clearly showed that by increasing the dietary fiber concentration of WB from 1 to 8% significantly reduced the number of colon tumors/group. When the influence of 8% dietary fiber from WB on the development of colon tumors was compared with that of PS (WB:PS = 0:100), no significant difference was observed. However, combinations of WB and PS showed a greater protective effect than either WB or PS alone, at comparable levels of dietary fiber. The 50:50 combination of WB and PS showed maximum protection, while 25:75 and 75:25 combinations both produced intermediate effects. None of the diets showed any significant effect on the normal growth of rats. The results indicate that WB and PS fiber alone, and to a greater degree in combination, can offer protection against colon cancer promoted by high fat, low calcium diets. Diets that include wheat bran in combination with psyllium could be an effective means of reducing colon cancer risk in human populations addicted to high risk western diets.

Adaptative responses of tobacco callus cells to simulated microgravity by compensation.

Under the rotation-induced gravity compensation, growth rate of callus was repressed by about 44%. Its osmotic and water potential declined by about 22 and 27% respectively. The content of soluble sugar was enhanced by about 123% and that of K+ by about 25%. The permeability of plasmic membrane increased and the lipid peroxidation intensified. When the callus grown under clinostatting were subcultured and returned to stationary conditions, the growth rates and related physiological indications were restored again to or near to the level of the control (SC). Electron microscopic studies showed that nuclear membrane was invaginated so deeply that some of the nuclei were like a starfish. Rough endoplasmic reticulum was diminished. The smooth one observed on the surface of slices was lengthened by almost 8.9 times of the control (SC), the longest one reached to 42 micrometers. They were often concentrated in a corner of the cell. Some of them were rolled into tube-shapes. The amyloplasts were without starch grain. It is assumed that the responses of plant cell to microgravity may be a sort of tolerable unloading reaction on endomembrane system.

The effect of high-risk and low-risk diets on aberrant crypt and colonic tumor formation in Fischer-344 rats.

Eighty Fischer-344 male rats were divided into eight groups. Half the groups were given a high-risk diet (HRD) that was high in fat, low in fiber and low in calcium, while the remaining groups were given a low-risk diet (LRD) that was low in fat, high in fiber and high in calcium. After 4 weeks, four groups were then given two weekly s.c. injections of azoxymethane (AOM) (15 mg/kg body wt), and four groups were given saline injections. At the end of 6 weeks the rats were either continued on HRD, LRD, or crossed over from HRD to LRD, or LRD to HRD for an additional 6 weeks. The rats were then killed and the influence of different dietary regimens on the induction of foci of aberrant crypts (AC) in their colons was compared. The number of foci of AC was highest in the AOM-injected HRD/HRD dietary group (8.83 +/- 0.98), followed by the AOM-injected LRD/HRD group (5.37 +/- 0.75), the HRD/LRD group (3.32 +/- 0.36) and the LRD/LRD group (2.93 +/- 0.32). Except for the HRD/HRD control group, which developed a small but significant number of foci of AC (1.24 +/- 0.19), the other saline-injected dietary groups showed no significant numbers of foci of AC. Two groups of rats on HRD/HRD (AOM and saline-injected), and two groups of rats on HRD/LRD (AOM and saline-injected) were continued on HRD and LRD respectively for an additional 14 weeks. A continuous HRD in AOM-injected rats induced colon tumors in 92% of rats, while the crossover from HRD to LRD suppressed the tumor incidence to 33%. Neither diet induced any tumors in saline-injected rats. The results clearly show that the influence of HRD and LRD on the induction of foci of AC and their distribution in the colon, correlated with the induction and distribution of tumors in the colon.

Cavity-enhanced photothermal spectroscopy: dynamics, sensitivity, and spatial resolution.

The spectrally resolved low-level absorption of thin films and of solid and liquid surfaces was measured by cavity-enhanced photothermal spectroscopy. The technique is ultrasensitive and can determine surfacespecific absorbances alpha(omega) ~ 10(-6) at a power density of 10(4)W/cm(2). Both cases of continuous wave and modulated laser light absorption were studied experimentally and are interpreted theoretically. It is shown that it is possible to achieve a spatial resolution of absorbance variations in the few-micrometer range. The thermal diffusivity can also be simultaneously measured by observing the time evolution of the surface temperature during laser irradiation.

Cloning and partial sequence of a cDNA for rabbit prothrombin.

A 1466 base pair cDNA for rabbit prothrombin has been isolated and partially sequenced. The deduced amino acid sequence shows considerable homology with the sequences of human and bovine prothrombin. The cDNA extends from the equivalent of nucleotide 516 in the bovine sequence through the coding region and 99 nucleotides in the 3' non-coding region.

Surface absorption measurements of thin films by cavity-enhanced photothermal spectroscopy.

Cavity-enhanced photothermal spectroscopy has been applied to perform ultrasensitive absorption measurements on thin metallic and high-reflectivity dielectric films. The novel method can be employed to determine minute surface-specific absorbances of alpha in the range of a few parts in 10(6) and has high sensitivity since the sample is placed inside a resonant optical cavity. Spatial-, spectral-, and time-resolved measurements were carried out. Laser surface heating calculations have been performed and can be evaluated to yield the thermal diffusivity of the thin films with a resolution at the level of a few micrometers.

Reevaluation of limited side-to-side portacaval shunt.

Although the results of limited side-to-side portacaval shunt were better than those of other shunts, postoperative encephalopathy still occurred in 10.2% of the patients. To determine the relationship between the diameter of anastomotic stoma and the development of postoperative encephalopathy, animal experiments and clinical observations were carried out. In 4 of 8 dogs in 3 months after limited side-to-side portacaval shunt and in 6 patients with postoperative encephalopathy, there was significant augmentation of the diameter of anastomotic stoma. To prevent the widening of anastomotic stoma caused by blood flow under high pressure, a limiting ring of 10 mm in diameter was put around the anastomotic site during operation in 21 patients with portal hypertension. Follow-up for 3-15 months (average 6 months) showed that there was no evidence of postoperative encephalopathy and rebleeding. A ring of same kind was put around the dilated anastomotic stoma during exploration in the 6 patients, and all their cerebral symptoms and signs disappeared completely soon after the second operation.

Comparison of the effects of 4-methylhistamine on the cell-cycle response between CFU-s and its subpopulation.

When bone marrow cells were treated with an H2-receptor agonist (4-methylhistamine 10(-8) M) before treatment with hydroxyurea (10(-3) M), the suicide rate of spleen colony-forming units (CFU-s) as a whole rose significantly. The rabbit antimouse brain serum (RAMBS)-resistant CFU-s subpopulation was also significantly elevated. Prior treatment of bone marrow cells with cimetidine would prevent this effect of 4-methylhistamine (4-MH). These findings not only confirm that 4-MH can trigger mouse bone marrow CFU-s to enter a DNA synthetic phase of the cell cycle, but also suggest that the RAMBS-resistant CFU-s subpopulation is more sensitive to the effect of 4-MH. Furthermore, this suggests that concentrations of the histamine receptor change during the developmental process of CFU-s.