Internet use time and subjective well-being during the COVID-19 outbreak: serial mediation of problematic internet use and self-esteem

The coronavirus disease (COVID-19) outbreak is a threat to adolescents' mental health and livelihoods, and lowers their subjective well-being (SWB). Expanding on previous literatures, this study examined whether internet use time was related to SWB and whether this relationship was mediated by problematic internet use (PIU) and self-esteem during the COVID-19 outbreak. In Taiwan, the COVID-19 epidemic broke out in February, 2020. During March 2 to 27, this study recruited a total of 1,060 adolescents from junior high schools by both stratified and cluster sampling, and administered a comprehensive investigation. The results displayed that SWB was significantly and negatively predicted by internet use time. PIU fully mediated the relationship. Moreover, PIU predicted a decrease of self-esteem, which played a full mediation role between PIU and SWB. The results provide evidence in explaining how increased internet use time is associated with a greater level of PIU, which relates to lower self-esteem, correlating with lower SWB in adolescents. This study can provide reference to mental health organizations and educational agencies to design appropriate SWB promotion programs for the junior high school population in terms of epidemic prevention.

Mediating role of depression in the association between alexithymia and nonsuicidal self-injury in a representative sample of adolescents in Taiwan

BACKGROUND

Nock's (2009) integrated theoretical model suggests that specific intrapersonal vulnerability factors caused by distal risk factors contribute to the development of nonsuicidal self-injury (NSSI). Alexithymia and depression have been found to predict NSSI. Based on Nock's model, alexithymia plays a distal risk factor role to increase the risk of depression-an intrapersonal vulnerability factor-and further increase the risk of NSSI. However, small or unrepresentative samples in past studies limit the generalizability of the results. This study examined the roles of depression and alexithymia in predicting NSSI, as well as the mediating effect of depression in the relation between alexithymia and NSSI in a large representative sample of adolescents in Taiwan.

METHODS

Using a cross-sectional study design, a large representative sample of 2,170 senior high school students in Taiwan was assessed by self-report measures of alexithymia, depression, and NSSI. Mediation analyses were performed to examine whether the relation between alexithymia and NSSI was mediated by depression. The questionnaires were administered in classrooms.

RESULTS

Results showed that alexithymia positively predicted NSSI (β = 0.23, p < .001) and depression can also positively predict NSSI (β = 0.41, p < .001). Additionally, the association between alexithymia and NSSI was fully mediated by depression.

CONCLUSIONS

This study data provided evidence for the mediating role of depression between alexithymia and NSSI, which can be explained by Nock's (2009) integrated theoretical model. The implications of the findings for future research and intervention were discussed.

Prevalence and psychosocial risk factors of nonsuicidal self-injury among adolescents during the COVID-19 outbreak

The research investigated the prevalence of nonsuicidal self-injury (NSSI) during the COVID-19 outbreak and identified the psychosocial risk factors among junior high school students in Taiwan. Cross-sectional design was applied and 1,060 participants (Mage = 14.66, SD = 0.86 years) were recruited into the study. The prevalence of NSSI was found to be 40.9% (95% confidence interval, 37.9%-43.9%) during the COVID-19 outbreak. The results suggested that the self-injurers group were mostly female, and scored significantly higher in neuroticism, depression, impulsivity, alexithymia, virtual social support, dissatisfaction with academic performance, and lower in subjective wellbeing, self-esteem, actual social support, and family function than the non-injurers group. In addition, high neuroticism, low self-esteem, high virtual social support, high impulsivity, and high alexithymia were independently predictive in the logistic regression analysis. The principal results of this study suggested that NSSI was extremely prevalent among adolescents during the COVID-19 outbreak, and in particularly, personality and virtual environment risk factors and enhancing self-esteem should be the focus of NSSI preventive strategies when targeting this age population. Our results provide a reference towards designing NSSI prevention programs geared toward the high school population during the COVID-19 pandemic.

Influence of red mud on mechanical and durability performance of self-compacting concrete

Red mud is a hazardous waste material produced during alkaline leaching of bauxite in the Bayer process. This study proposed the use of red mud to replace fly ash in self-compacting concrete (SCC) and the influences of red mud on fresh and hardened properties, and durability performances of SCC were studied. The fresh concrete results show that red mud had a slight negative impact on the fresh properties of SCC. The hardened concrete results show that the mechanical strength of concrete increased with increasing of red mud content. The half-cell potential test results indicated that red mud had a significant effect on restraining the corrosion process in SCC. Compared to the control sample, the red mud samples suffered less corrosion. Cracks associated with corrosion of reinforcement were observed in RMC0 and RMC100 samples after 28 day accelerated corrosion test. The ICP-MS results showed that there's no significant difference in metal elements among the solutions regardless the red mud content in concrete.The relative corrosion rate test results suggested that red mud can suppress the corrosion current. The SCC samples consisting 75% red mud performed the best resistance to corrosion according to the results of half-cell potentials and mass loss of rebar.

A microsystem with varying-length electrode arrays for auditory nerve prostheses

This paper reports the design, fabrication and simulation of a novel array of micromachined electrodes with different lengths for use in auditory nerve prostheses. A 10 x 10 array is created in a 1 mm2 on silicon with bulk micromachining technology. The electrode lengths vary from 200 microm to 400 microm. This design could provide access to most fascicles within the auditory nerve and thus allow stimulation of a broad tonotopic range within the nerve fiber. A multichannel ultra-low power circuit is also designed, fabricated, and tested for neural signal recording. The chip is fabricated in 0.5 microm AMI CMOS technology with a die size of 1.5 mm x 1.5 mm. The total power consumption is less than 100 microW.

Lycobetaine acts as a selective topoisomerase II beta poison and inhibits the growth of human tumour cells

The phenanthridine alkaloid lycobetaine is a minor constituent of Amaryllidaceae. Inhibition of cell growth was studied in the clonogenic assay on 21 human tumour xenografts (mean IC(50) = 0.8 microM). The growth of human leukaemia cell lines was also potently inhibited (mean IC(50) = 1.3 microM). Athymic nude mice, carrying s.c. implanted human gastric tumour xenograft GXF251, were treated i.p. with lycobetaine for 4 weeks, resulting in a marked tumour growth delay. Lycobetaine was found to act as a specific topoisomerase II beta poison. In the presence of calf thymus DNA, pure recombinant human topoisomerase II beta protein was selectively depleted from SDS-gels, whereas no depletion of topoisomerase II alpha protein was observed. In A431 cells immunoband-depletion of topoisomerase II beta was induced, suggesting stabilization of the covalent catalytic DNA-intermediate in living cells. It is reasonable to assume that this mechanism will cause or at least contribute significantly to the antitumour activity.

[The development of a double point sensor for the pulse]

This article has introduced the research and design on a double point sensor for the comprehensive pulse. The difference of this sensor from the single point sensor is that it is able to obtain a mechanics parameter from the pulse signals of the traditional Chinese medicine. This would be a great help for the more detailed quantitative analysis of the pulse signals of the traditional Chinese medicine. It has also explored the contribution of the double point sensor to the clinical medicine.

Utilization of sorbed compounds by microorganisms specifically isolated for that purpose

A bacterium obtained by enrichment on nonsorbed phenanthrene was unable to degrade phenanthrene sorbed to polyacrylic beads and had little activity on phenanthrene sorbed to lake-bottom sediment. A bacterium obtained by enrichment on phenanthrene sorbed to polyacrylic beads readily mineralized the compound sorbed to the beads or the sediment. Degradation by the second bacterium of phenanthrene sorbed to beads 38-63 microns or 63-150 microns in diameter was more rapid than the rate of desorption of the hydrocarbon in the absence of the bacterium. Little degradation of sorbed, nonleachable phenanthrene in soil was effected by another isolate obtained by enrichment with the nonsorbed hydrocarbon, but a mixed culture and the bacterium obtained by enrichment on the sorbed compound extensively degraded phenanthrene. Because microorganisms specifically obtained for their capacity to degrade sorbed phenanthrene are more active than species not specialized for use of the bound compound, we suggest that microorganisms enriched on nonsorbed compounds may not be appropriate for evaluation of biodegradation and bioremediation of sorbed compounds.

Reversible impairment of myocardial contractility due to hypercarbic acidosis in the isolated perfused rat heart

BACKGROUND AND METHODS

Striking increases in PCO2 of the myocardium have recently been documented during cardiac arrest. The purpose of the present study was to investigate selective effects of hypercarbia as distinct from acidosis on left ventricular contractile function and oxygen utilization. An isolated, spontaneously beating rat heart preparation was utilized. The perfusate was equilibrated with gases containing 5%, 10%, 20%, and 30% CO2. In a subset of experiments, the [H+] was adjusted independently of PCO2 by decreasing the concentration of HCO3-.

RESULTS

When the PCO2 of the perfusate was progressively increased from 36 to 146 torr (4.8 to 29.5 kPa), the left ventricular systolic pressure (LVSP) generated by the isolated heart and the maximum rate of pressure change in the left ventricle (dP/dt) were decreased to 20% of their control values. However, comparable acidosis in the absence of hypercarbia produced only minimal decreases in the LVSP or dP/dt such that contractility remained at greater than or equal to 88%. Increases in the perfusate PCO2 but not in the perfusate H+ were highly correlated with decreases in both myocardial contractility and oxygen consumption (r2 = .88).

CONCLUSION

Hypercarbia rather than acidosis accounts for decreased contractility and oxygen utilization in the isolated perfused rat heart.

Androgen-linked alkylating agents: biological activity in methylnitrosourea-induced rat mammary carcinoma

This article gives a comprehensive survey on the anticancer activity of nitrosoureas linked to steroidal androgens in methylnitrosourea (MMU)-induced rat mammary carcinoma. cis-Androsterone, testosterone, 19-nortestosterone and 5-alpha-dihydrotestosterone were used as carrier hormones and were linked to various cytotoxic N-[N'-(2-chloroethyl)-N'-nitrosocarbamoyl] (CNC)-aminoacids and to N-(2-hydroxyethyl)-N'-(2-chloroethyl)-N'-nitrosourea hemisuccinate (HECNU-hemisuccinate). In the MNU-model used esters of dihydrotestosterone (DHT) invariably were more active and less toxic than those of testosterone, nortestosterone and cis-androsterone. Within the DHT esters of CNC-aminoacids those of CNC-glycine, CNC-methionine and CNC-alanine showed the highest antineoplastic activities and superiority compared with equimolar dosages of their unlinked mixtures. Additionally, CNC-alanine-DHT ester had the highest therapeutic ratio of all agents investigated. HECNU-hemisuccinate-DHT ester, on the other hand, achieved even higher antitumor activity at the optimal dose but had a narrower therapeutic ratio. No obvious correlation between antineoplastic efficacy and receptor binding affinity could be demonstrated, but, to be active, a conjugate apparently had to have some receptor binding affinity for both androgen and progesterone receptors. The results obtained indicate that linking antineoplastic agents to transport molecules with affinity to steroid receptors is a highly promising approach to obtain drugs with specific activity in steroid receptor containing tumors.

Synthesis and antineoplastic activity of CNC-cysteamine and related compounds

N'-[N-(2-Chloroethyl)-N-nitroso]carbamoyl cysteamine (CNC-cysteamine) and several related compounds have been synthesized and tested against L 1210 leukemia in mice. Reaction of N-(2-chloroethyl)-N-nitrosocarbamoyl azide (CNC-azide) with cysteamine yielded CNC-cysteamine and bis(CNC)cystamine. Reaction of CNC-azide with cystamine in the presence of triethylamine gave bis(CNC)cystamine. Unexpectedly, formation of CNC-cystamine carboxylazide as a minor reaction product was also observed. N-(2-Chloroethyl)carbamoyl cysteamine 2-chloroethylcarbamate was formed when 2-chloroethyl isocyanate was reacted with cysteamine. Nitrosation of this cysteamine N,S-dicarbamoyl derivative led to formation of a mixture of two dinitroso isomers. Preliminary testing of the newly synthesized CNC-derivatives against L 1210 leukemia in mice revealed that CNC-cysteamine, its disulfide bis(CNC)cystamine and CNC-cystamine carboxylazide were highly active against L 1210 leukemia.

Metabolism of, and DNA methylation by, N-nitrosomethylbenzylamine in chicken

The metabolism of 14C-nitrosomethylbenzylamine (NMBA) was studied in chicken. Following a single IV dose of 2 mg/kg, 14C-NMBA was cleared from the blood with a half-life of 3.8 min. At 10 min after administration 14C-NMBA was totally metabolized in the liver, whereas in the esophagus no measurable metabolic degradation had taken place. Maximum exhalation of radioactive CO2 occurred 1 h after IV administration of NMBA, and 11% of the total radioactivity had been exhaled as CO2 by 8 h. These results are compared with data on the metabolism of NMBA in the rat. The analysis of methylated bases in the DNA of different organs of chicken revealed that 7-me guanine was formed in all organs. The highest amount of 0(6)-me guanine was found in liver DNA, followed by kidney DNA. O6-me guanine was not detectable in any other organ. The O6-/7-me guanine ratio in DNA was calculated to be 0.05 and 0.02 for liver and 0.01 for kidneys.