Sonochemical synthesis of bioinspired graphene oxide-zinc oxide hydrogel for antibacterial painting on biodegradable polylactide film.

Graphene oxide nanosheet (GO) is a multifunctional platform for binding with nanoparticles and stacking with two dimensional substrates. In this study, GO nanosheets were sonochemically decorated with zinc oxide nanoparticles (ZnO) and self-assembled into a hydrogel of GO-ZnO nanocomposite. The GO-ZnO hydrogel structure is a bioinspired approach for preserving graphene-based nanosheets from van der Waals stacking. X-ray diffraction analysis (XRD) showed that the sonochemical synthesis led to the formation of ZnO crystals on GO platforms. High water content (97.2%) of GO-ZnO hydrogel provided good property of ultrasonic dispersibility in water. Ultraviolet-visible spectroscopic analysis (UV-vis) revealed that optical band gap energy of ZnO nanoparticles (∼3.2 eV) GO-ZnO nanosheets (∼2.83 eV). Agar well diffusion tests presented effective antibacterial activities of GO-ZnO hydrogel against gram-negative bacteria (E. coli) and gram-positive bacteria (S. aureus). Especially, GO-ZnO hydrogel was directly used for brush painting on biodegradable polylactide (PLA) thin films. Graphene-based nanosheets with large surface area are key to van der Waals stacking and adhesion of GO-ZnO coating to the PLA substrate. The GO-ZnO/PLA films were characterized using photography, light transmittance spectroscopy, coating stability, scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopic mapping (EDS), antibacterial test and mechanical tensile measurement. Specifically, GO-ZnO coating on PLA substrate exhibited stability in aqueous food simulants for packaging application. GO-ZnO coating inhibited the infectious growth ofE. colibiofilm. GO-ZnO/PLA films had strong tensile strength and elastic modulus. As a result, the investigation of antibacterial GO-ZnO hydrogel and GO-ZnO coating on PLA film is fundamental for sustainable development of packaging and biomedical applications.

Drug resistance and the genotypic characteristics of rpoB and katG in rifampicin- and/or isoniazid-resistant Mycobacterium tuberculosis isolates in central Vietnam.

BACKGROUND: Tuberculosis (TB) and drug-resistant TB (DR-TB) are national health burdens in Vietnam. In this study, we investigated the prevalence of rifampicin (RIF) and/or isoniazid (isonicotinic acid hydrazide, INH) resistance in patients with suspected TB, and applied appropriate techniques to help rapidly target DR-TB. METHODS: In total, 1,547 clinical specimens were collected and cultured using the BACTEC MGIT system (Becton Dickinson and Co.). A resazurin microtiter assay (REMA) was used to determine the proportions of RIF and/or INH resistance. A real-time polymerase chain reaction panel with TaqMan probes was employed to identify the mutations of rpoB and katG associated with DR-TB in clinical isolates. Genotyping of the identified mutations was also performed. RESULTS: A total of 468 Mycobacterium tuberculosis isolates were identified using the REMA. Of these isolates, 106 (22.6%) were found to be resistant to 1 or both antibiotics. Of the resistant isolates, 74 isolates (69.8%) were resistant to isoniazid (INH) only, while 1 isolate (0.94%) was resistant to RIF only. Notably, 31 isolates (29.24%) were resistant to both antibiotics. Of the 41 phenotypically INH-resistant isolates, 19 (46.3%) had the Ser315Thr mutation. There were 8 different rpoB mutations in 22 (68.8%) of the RIF-resistant isolates. The most frequently detected mutations were at codons 531 (37.5%), 526 (18.8%), and 516 (6.3%). CONCLUSION: To help prevent new cases of DR-TB in Vietnam, it is crucial to gain a comprehensive understanding of the genotypic DR-TB isolates.

What if delivery riders quit? Challenges to last-mile logistics during the Covid-19 pandemic.

Notoriously precarious, hazardous, and stressful, delivery jobs became even more onerous and dangerous during the pandemic. In this study, set in Ho Chi Minh City, Vietnam, we applied Structural Equation Modelling to a large sample of primary data to measure delivery riders' intention to quit their jobs at the height of the pandemic. We found that job burnout was the key trigger to the intention to quit whereas the risk of Covid-19 infection did not directly affect this behavioral intention. Female riders, migrants, persons living with chronic diseases, and those who had seen their income decimated during the pandemic were more likely to want to quit their job. But if a mass of delivery drivers or riders had failed to show up for work, the last-mile delivery sector would have become paralysed, leaving individuals in various states of lockdown or isolation without food and supplies. As the sector is poised to retain its importance in the post-pandemic period, we recommend a number of approaches for both private companies and public policy makers to persuade riders to stay in their jobs. First and foremost, strategies to prevent and mitigate job burnout should be formulated.

Health and safety risks faced by delivery riders during the Covid-19 pandemic.

OBJECTIVES: Delivery riders have been front-line workers throughout the pandemic but little is known about their own health and safety during this time. This study explores the health and safety issues facing delivery riders in Ho Chi Minh City, Vietnam, during the Covid-19 pandemic, in particular during the second lockdown (May-October 2021). METHOD: A web-based survey of more than 800 riders was conducted in August-September 2021. Following descriptive statistics, four logit models were fitted to examine the factors associated with (a) sanitizing one's hands, (b) using a face shield, (c) contracting a new health issue, and (d) engaging in riskier traffic behaviors during the lockdown. RESULTS: The riders who were less consistent in adopting health and safety measures tended to be male, older, less-educated, and vaccinated. Also, they were under greater financial pressure and had suffered a larger loss of income during the pandemic. To recover the loss, they worked longer hours and felt under more intense pressure at work. The job pressure, long working hours, and financial burdens led many drivers to adopt risky traffic behaviors, such as speeding. Conversely, where the companies and co-workers were more supportive, riders tended to adopt health prevention measures more often. Fear of Covid-19 also acted as a facilitator. Job and financial pressure combined with the fear of contracting the virus contributed to the occurrence of new heath issues during the pandemic. Again, support from the company and co-workers helped to reduce the risk of new health problems emerging. CONCLUSION: In Ho Chi Minh City and other Global South megacities that employ tens of thousands of riders, ensuring their health and safety is important to support both private businesses and public health. Overall, companies should assume a much larger responsibility here.

Movements modulate cortical activities evoked by noxious stimulation.

To evaluate the effects of movement on cortical activities evoked by noxious stimulation, we recorded magnetoencephalography following noxious YAG laser stimulation applied to the dorsum of the left hand in normal volunteers. Results of the present study can be summarized as follows: (1) active movement of the hand ipsilateral to the side of noxious stimulation resulted in significant attenuation of both primary and secondary somatosensory cortices (SI and SII) in the hemisphere contralateral to the stimulated hand (cSI and cSII). Activity in the hemisphere ipsilateral to the side of stimulation (iSII) was not affected. (2) Active movement of the hand contralateral to the side of noxious stimulation resulted in significant attenuation of cSII. Activity in cSI and iSII was not affected. (3) Passive movement of the hand ipsilateral to the side of noxious stimulation resulted in significant attenuation of cSI. Activity in cSII and iSII was not affected. (4) Visual analogue scale (VAS) changes showed a similar pattern to the amplitude changes of cSII. These results suggest that activities in three regions are modulated by movements differently. Inhibition in cSI was considered to be mainly due to an interaction in SI by the signals ascending from the stimulated and movement hand. Inhibition in cSII was considered to be mainly due to particular brain activities relating to motor execution and/or movement execution associated with a specific attention effect. In addition, since VAS changes showed a similar relationship with the amplitude changes of cSII, cSII may play a role in pain perception.

Effecty of Wofatox with long-term low dose to ultra and micro-structure of the rats’ liver

Study on the changes of ultra and micro-structure of the liver of white rats, which was effected by Wafatox with longed-low dose. Rats with the beginning body mass of 120-150g were everyday oral administrated by oil containing 0.1% of Wafatox with the dose of 0.5mg/kg of their body mass (similarly with 1/70 dose of LD50 for white rats). They were killed by stages of 10, 20, 30, 40 and 50 days from the first oral administration. The results: in clinical, the rat’s intoxicated symptoms were not clear, but the changes in the liver were clearly shown. In the liver, there were some points of necrozism, hepatocytes strongly regressed at the level of ultra and micro-structure. The portals areas and the liver’s tissues were infiltrated by cells like lymphocytes. There were happened stretching veins, stagnating blood and particularly, getting thicker and thicker in the walls of veins of central lobules of the rats’ liver at every stage. Up to the 50th day of intoxication by Wafatox, the quantity of two-nucleus hepatocytes was decreased and mitotic activity of hepatocytes was not increased

The impact of wofatox on the changes in morphological structure and mitotic activity of liver rats with 2/3 liver of cut off

Poisoned the rats by pesticide wofatox with dose 10mg/kg of their body weight. After 60 minutes, cut off two third of liver by method of Higgins and Anderson. The changes in morphological structures and mitotic activity of liver rats were as follows: Lesions in the liver were markedly manifested, but were not prolong. The mitotic activity of hematocytes decreased. The regenenation of liver weakly manifested

Changes morphological and chemical structure of rat liver intoxicated by pesticide bassa

Poison the rats by pesticide Bassa with dose 205mg/kg of their body mass. Observe the changes morphological and chemical structure of rats liver, remark: The changes in the liver were clearly show on the thirdly days, find expression: disorder circulation of the blood, degradation cytoplasma of hepatocytes, number hepatocytes with 2 nuclei diminished, decreased in quantities glycogen, increased in the number lipid. After the third day, regeneration of the liver rapidly happened

Sensory perception during sleep in humans: a magnetoencephalograhic study.

We reported the changes of brain responses during sleep following auditory, visual, somatosensory and painful somatosensory stimulation by using magnetoencephalography (MEG). Surprisingly, very large changes were found under all conditions, although the changes in each were not the same. However, there are some common findings. Short-latency components, reflecting the primary cortical activities generated in the primary sensory cortex for each stimulus kind, show no significant change, or are slightly prolonged in latency and decreased in amplitude. These findings indicate that the neuronal activities in the primary sensory cortex are not affected or are only slightly inhibited during sleep. By contrast, middle- and long-latency components, probably reflecting secondary activities, are much affected during sleep. Since the dipole location is changed (auditory stimulation), unchanged (somatosensory stimulation) or vague (visual stimulation) between the state of being awake and asleep, different regions responsible for such changes of activity may be one explanation, although the activated regions are very close to each other. The enhancement of activities probably indicates two possibilities, an increase in the activity of excitatory systems during sleep, or a decrease in the activity of some inhibitory systems, which are active in the awake state. We have no evidence to support either, but we prefer the latter, since it is difficult to consider why neuronal activities would be increased during sleep.

Effects of sleep on pain-related somatosensory evoked magnetic fields in humans.

We investigated the effects of sleep on pain-related somatosensory evoked magnetic fields (SEFs) following painful electrical stimulation to identify the mechanisms generating them in both fast A-beta fibers relating to touch and slow A-delta fibers relating to pain. While the subjects were awake, non-painful and painful electrical stimulations were applied, and while asleep, painful stimulation was applied to the left index finger. During awake, five components (1M-5M) were identified following both non-painful and painful stimulation, but the 4M and 5M at around 70-100 ms and 140-180 ms, respectively, were significantly enhanced following painful stimulation. During sleep, 1M and 2M generated in the primary somatosensory cortex (SI) did not show a significant change, 3M in SI showed a slight but significant amplitude reduction, and 4M and 5M generated in both SI and the secondary somatosensory cortex (SII) were significantly decreased in amplitude or disappeared. The 4M and 5M are complicated components generated in SI and SII ascending through both A-beta fibers and A-delta fibers. They are specifically enhanced by painful stimulation due to an increase of signals ascending through A-delta fibers, and are markedly decreased during sleep, because they much involve cognitive function.

Cerebral responses following stimulation of unmyelinated C-fibers in humans: electro- and magneto-encephalographic study.

There are two kinds of pain, a sharp pain ascending through Adelta fibers (first pain) and a second burning pain ascending though C fibers (second pain). By using a novel method, the application of a low intensity CO(2) laser beam to a tiny area of skin using a very thin aluminum plate with numerous tiny holes as a spatial filter, we succeeded in selectively stimulating unmyelinated C fibers of the skin in humans, and could record consistent and clear brain responses using electroencephalography (EEG) and magnetoencephalography (MEG). The conduction velocity (CV) of the C fibers of the peripheral nerve and spinal cord, probably spinothalamic tract (STT), is approximately 1-4 m/s, which is significantly slower than that of Adelta (approximately 10-15 m/s) and Abeta fibers (approximately 50-70 m/s). This method should be very useful for clinical application. Following C fiber stimulation, primary and secondary somatosensory cortices (SI and SII) are simultaneously activated in the cerebral hemisphere contralateral to the stimulation, and then, SII in the hemisphere ipsilateral to the stimulation is activated. These early responses are easily detected by MEG. Then, probably limbic systems such as insula and cingulate cortex are activated, and those activities reflected in EEG components. Investigations of the cortical processing in pain perception including both first and second pain should provide a better understanding of pain perception and, therefore, contribute to pain relief in clinical medicine.

Some remark on the correlation of semen parameters of male infertility

1.000 semen samples of male partner of infertile couples ranging from 20 to 49 year old age were studied. Some parameters such as semen volume, pH, spermatozoa motility, cencentration and morphology were evaluated and leucocyte numbers were counted. Results showed low concentration occurred in the samples of low volume of sperm or of pH < 7.2 (under normal limit). Spermatozoa poor motility was more prequent in the samples of low sperm concentrations of abnormal morphology or of the samples having high density of leucocyte. In the samples of low concentrations of spermatozoa, abnormal morphology of spermatozoa was also frequent.