[Investigation and analysis on the detection of IgG antibodies against the rubella virus among rural childbearing-age women in preconception period in Yunnan Province from 2013 to 2019]

A study was conducted on rural women of childbearing age aged 20-49 who underwent the National Free Preconception Health Examination Project (NFPHEP)in Yunnan Province from 2013 to 2019. Descriptive analysis was conducted to determine the negative rate of IgG antibodies against the rubella virus and its differences among various socio-demographic characteristics. Among the 1 511 203 study subjects, the negative rate of IgG antibodies against the rubella virus was 24.36%. Only 2.64% of the population had received rubella virus vaccine. The negative rate of IgG antibodies among rural childbearing-age women in the preconception period in Yunnan Province decreased with age and educational level (Ptrend<0.001). The negative rate of IgG antibodies in ethnic minority women of childbearing age in the preconception period (25.19%) was higher than that of Han women (23.88%). Among the 22 ethnic groups with over 1 000 participants, the negative rates of IgG antibodies in women of childbearing age from the Blang (32.85%), Bouyei (31.03%), Zhuang (31.01%), and Miao (30.70%) ethnic groups were higher than those of women from other ethnic groups. Among the 16 states (cities) in Yunnan Province, the negative rate of IgG antibodies in pregnant women of childbearing age in Wenshan Zhuang and Miao Autonomous Prefecture (38.06%) and Lincang City (32.63%) was higher than that in other states (cities). The negative rate of serum IgG antibodies in women who reported having received rubella virus vaccine (18.60%) was lower than that in other non-vaccinated populations (24.52%). The proportion of rural women of childbearing age in Yunnan Province who were susceptible to the rubella virus before pregnancy was still high. It is necessary to promote rubella vaccination among people susceptible to rubella, especially pregnant women, to prevent rubella virus infection and reduce the incidence rate and disease burden of rubella people.

New dose-response model and SARS-CoV-2 quanta emission rates for calculating the long-range airborne infection risk

Predictive models for airborne infection risk have been extensively used during the pandemic, but there is yet still no consensus on a common approach, which may create misinterpretation of results among public health experts and engineers designing building ventilation. In this study we applied the latest data on viral load, aerosol droplet sizes and removal mechanisms to improve the Wells Riley model by introducing the following novelties i) a new model to calculate the total volume of respiratory fluid exhaled per unit time ii) developing a novel viral dose-based generation rate model for dehydrated droplets after expiration iii) deriving a novel quanta-RNA relationship for various strains of SARS-CoV-2 iv) proposing a method to account for the incomplete mixing conditions. These new approaches considerably changed previous estimates and allowed to determine more accurate average quanta emission rates including omicron variant. These quanta values for the original strain of 0.13 and 3.8 quanta/h for breathing and speaking and the virus variant multipliers may be used for simple hand calculations of probability of infection or with developed model operating with six size ranges of aerosol droplets to calculate the effect of ventilation and other removal mechanisms. The model developed is made available as an open-source tool.

[Investigation of ABO and RhD blood groups in childbearing age people in rural areas of Yunnan Province]

The participants in this study were 20-49 years old rural childbearing age people who received the National Free Preconception Health Examination Project (NFPHEP) in Yunnan Province during 2013 to 2019. The proportion of ABO and RhD blood groups among different ethnic groups and different areas were calculated. The proportion of 2 748 131 participants with blood group A phenotype was highest (32.60%), followed by O (30.60%), B (27.33%) and AB (9.47%). In the RhD blood system, the proportion of the RhD positivity (RhD+) and RhD negativity (RhD-) group were 99.29% and 0.71% respectively. The proportions blood groups were significantly different among ethnic groups and areas (all P<0.001). Among 18 ethnic groups with more than 3 000 participants, Yao (42.75%), Bouyei (40.58%) and Dai (40.37%) ethnic groups had higher proportion of blood group O phenotype than other ethnic groups. Wa ethnic groups had highest proportion of the A (40.15%) and AB phenotypes (11.23%). Miao ethnic group (34.70%) and Lahu ethnic group (34.42%) had higher proportion of blood group B phenotype than other ethnic groups. Wa ethnic group had the highest proportion of RhD-group (1.88%). In all 16 prefectures of Yunnan, the proportion of blood group O phenotype was highest in Xishuangbanna Dai Autonomous Prefecture (40.27%). Baoshan city (36.39%), Lincang city (36.22%) and Dali Bai autonomous prefecture (36.06%) had higher proportion of blood group A phenotype than other regions. Diqing Tibetan Autonomous Prefecture (30.83%) and Qujing city (30.48%) had higher proportion of blood group B phenotype than other areas, while Zhaotong city had a highest proportion of blood group AB phenotype (11.19%). The proportion of RhD-group was highest in Honghe hani and Yi nationality autonomous prefecture(1.37%). The A RhD+(39.36%), A RhD-(0.78%), AB RhD+(11.03%), AB RhD-(0.20%) and O RhD-(0.48%) blood groups were higher proportion in Wa ethnic group than in other ethnic groups (P<0.001).

Zonal modeling of air distribution impact on the long-range airborne transmission risk of SARS-CoV-2

A widely used analytical model to quantitatively assess airborne infection risk is the Wells-Riley model which is limited to complete air mixing in a single zone. However, this assumption tends not to be feasible (or reality) for many situations. This study aimed to extend the Wells-Riley model so that the infection risk can be calculated in spaces where complete mixing is not present. Some more advanced ventilation concepts create either two horizontally divided air zones in spaces as displacement ventilation or the space may be divided into two vertical zones by downward plane jet as in protective-zone ventilation systems. This is done by evaluating the time-dependent distribution of infectious quanta in each zone and by solving the coupled system of differential equations based on the zonal quanta concentrations. This model introduces a novel approach by estimating the interzonal mixing factor based on previous experimental data for three types of ventilation systems: incomplete mixing ventilation, displacement ventilation, and protective zone ventilation. The modeling approach is applied to a room with one infected and one susceptible person present. The results show that using the Wells-Riley model based on the assumption of completely air mixing may considerably overestimate or underestimate the long-range airborne infection risk in rooms where air distribution is different than complete mixing, such as displacement ventilation, protected zone ventilation, warm air supplied from the ceiling, etc. Therefore, in spaces with non-uniform air distribution, a zonal modeling approach should be preferred in analytical models compared to the conventional single-zone Wells-Riley models when assessing long-range airborne transmission risk of infectious respiratory diseases.

Emergence of Spinons in Layered Trimer Iridate Ba_{4}Ir_{3}O_{10}

Spinons are well known as the elementary excitations of one-dimensional antiferromagnetic chains, but means to realize spinons in higher dimensions is the subject of intense research. Here, we use resonant x-ray scattering to study the layered trimer iridate Ba_{4}Ir_{3}O_{10}, which shows no magnetic order down to 0.2 K. An emergent one-dimensional spinon continuum is observed that can be well described by XXZ spin-1/2 chains with a magnetic exchange of ∼55  meV and a small Ising-like anisotropy. With 2% isovalent Sr doping, magnetic order appears below T_{N}=130  K along with sharper excitations in (Ba_{1-x}Sr_{x})_{4}Ir_{3}O_{10}. Combining our data with exact diagonalization calculations, we find that the frustrated intratrimer interactions effectively reduce the system into decoupled spin chains, the subtle balance of which can be easily tipped by perturbations such as chemical doping. Our results put Ba_{4}Ir_{3}O_{10} between the one-dimensional chain and two-dimensional quantum spin liquid scenarios, illustrating a new way to suppress magnetic order and realize fractional spinons.

Reducing the risk of viral contamination during the coronavirus pandemic by using a protective curtain in the operating room

Background

Airborne transmission diseases can transfer long and short distances via sneezing, coughing, and breathing. These airborne repertory particles can convert to aerosol particles and travel with airflow. During the Coronavirus disease 2019 (COVID-19) pandemic, many surgeries have been delayed, increasing the demand for establishing a clean environment for both patient and surgical team in the operating room.

Methods

This study aims to investigate the hypothesis of implementing a protective curtain to reduce the transmission of infectious contamination in the surgical microenvironment of an operating room. In this regard, the spread of an airborne transmission disease from the patient was evaluated, consequently, the exposure level of the surgical team. In the first part of this study, a mock surgical experiment was established in the operating room of an academic medical center in Norway. In the second part, the computational fluid dynamic technique was performed to investigate the spread of airborne infectious diseases. Furthermore, the field measurement was used to validate the numerical model and guarantee the accuracy of the applied numerical models.

Results

The results showed that the airborne infectious agents reached the breathing zone of the surgeons. However, using a protective curtain to separate the microenvironment between the head and lower body of the patient resulted in a 75% reduction in the spread of the virus to the breathing zone of the surgeons. The experimental results showed a surface temperature of 40 ˚C, which was about a 20 ˚C increase in temperature, at the wound area using a high intensity of the LED surgical lamps. Consequently, this temperature increase can raise the patient's thermal injury risk.

Conclusion

The novel method of using a protective curtain can increase the safety of the surgical team during the surgery with a COVID-19 patient in the operating room.

Modeling the impact of indoor relative humidity on the infection risk of five respiratory airborne viruses

With a modified version of the Wells-Riley model, we simulated the size distribution and dynamics of five airborne viruses (measles, influenza, SARS-CoV-2, human rhinovirus, and adenovirus) emitted from a speaking person in a typical residential setting over a relative humidity (RH) range of 20-80% and air temperature of 20-25 °C. Besides the size transformation of virus-containing droplets due to evaporation, respiratory absorption, and then removal by gravitational settling, the modified model also considered the removal mechanism by ventilation. The trend and magnitude of RH impact depended on the respiratory virus. For rhinovirus and adenovirus humidifying the indoor air from 20/30 to 50% will be increasing the relative infection risk, however, this relative infection risk increase will be negligible for rhinovirus and weak for adenovirus. Humidification will have a potential benefit in decreasing the infection risk only for influenza when there is a large infection risk decrease for humidifying from 20 to 50%. Regardless of the dry solution composition, humidification will overall increase the infection risk via long-range airborne transmission of SARS-CoV-2. Compared to humidification at a constant ventilation rate, increasing the ventilation rate to moderate levels 0.5 → 2.0 h^-1 will have a more beneficial infection risk decrease for all viruses except for influenza. Increasing the ventilation rate from low values of 0.5 h^-1 to higher levels of 6 h^-1 will have a dominating effect on reducing the infection risk regardless of virus type.

Experimental study on the exposure level of surgical staff to SARS-CoV-2 in operating rooms with mixing ventilation under negative pressure

The purpose of this study was to reveal the exposure level of surgical staff to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from the patient's nose and wound during operations on COVID-19 patients. The tracer gas N₂O is used to simulate SARS-CoV-2 from the patient's nose and wound. In this study, concentration levels of tracer gas were measured in the breathing zones of these surgical staff in the operating room under three pressure difference conditions: -5 pa-15 pa and -25 pa compared to the adjunction room. These influencing factors on exposure level are analyzed in terms of ventilation efficiency and the thermal plume distribution characteristics of the patient. The results show that the assistant surgeon faces 4 to 12 times higher levels of exposure to SARS-CoV-2 than other surgical staff. Increasing the pressure difference between the OR lab and adjunction room can reduce the level of exposure for the main surgeon and assistant surgeon. Turning on the cooling fan of the endoscope imager may result in a higher exposure level for the assistant surgeon. Surgical nurses outside of the surgical microenvironment are exposed to similar contaminant concentration levels in the breathing zone as in the exhaust. However, the ventilation efficiency is not constant near the surgical patient or in the rest of the room and will vary with a change in pressure difference. This may suggest that the air may not be fully mixed in the surgical microenvironment.

Can clothing systems and human activities in operating rooms with mixing ventilation systems help achieve 10 CFU/m3 level during orthopaedic surgeries?

The level of airborne microbial contamination in operating rooms (ORs) is an important indicator of indoor air quality and ensures a clean surgical environment. It is necessary to research how different factors affect the colony forming unit (CFU) level during surgery in a mixing ventilation (MV) operating room (OR) to fulfil an ultra-clean air requirement. The main objective of this study is to clarify the possibility of achieving the requirement for an ultraclean operating room (≤ 10 CFU/m³) with mixing ventilation from two factors of clothing and human activities. The experiment results verified that the average CFU/m³ of three of five mock-up surgeries was 8.5 which was below or equal to the ultra-clean requirement, while the other two mock-up surgeries did not meet the ultra-clean requirement. Surgical activities together with clothing level of surgical staff in ORs seem to be the most significant reason for the high CFU level during surgery. It is possible to achieve the ultraclean air requirement (≤ 10 CFU/m³) during a surgical process with proper clothing and low surgical activities in ORs. This study clarifies the effect of clothing and human activities on the CFU level in the surgical microenvironment in ORs and contributes to developing new code of products for the surgical team.

Processing Conditions Optimization for the Synthesis and Consolidation of High-Entropy Diborides

The fabrication by Spark Plasma Sintering (SPS) of bulk high entropy ceramics from powders obtained by Self-propagating High temperature Synthesis (SHS) is addressed in this work. The effect produced by the introduction of 1 wt.% of graphite to the powders before SPS is investigated under different temperature conditions. The final density and composition of sintered (Hf0.2Mo0.2Zr0.2Ti0.2Ta0.2)B2 and (Hf0.2Mo0.2Zr0.2Ti0.2Nb0.2)B2 ceramics are found to be negatively affected by the presence of oxide impurities in the powders. While product composition can be progressively improved when the temperature is increased from 1800 to 1950 °C, residual porosities remain relatively high if using additive-free powders. In contrast, the introduction of 1 wt.%C markedly allows for oxides elimination by carbothermal reduction mechanism. Products consolidation is correspondingly enhanced so that relative densities of about 97% are attained. Other than the latter effect, surface oxides removal also makes powders more reactive, thus the synthesis of single-phase products is promoted. In particular, fully homogeneous (Hf0.2Mo0.2Zr0.2Ti0.2Ta0.2)B2 ceramics are obtained at relatively lower temperature conditions (1850 °C).

Estimating the impact of indoor relative humidity on SARS-CoV-2 airborne transmission risk using a new modification of the Wells-Riley model

A novel modified version of the Wells-Riley model was used to estimate the impact of relative humidity (RH) on the removal of respiratory droplets containing the SARS-CoV-2 virus by deposition through gravitational settling and its inactivation by biological decay; the effect of RH on susceptibility to SARS-CoV-2 was not considered. These effects were compared with the removal achieved by increased ventilation rate with outdoor air. Modeling was performed assuming that the infected person talked continuously for 60 and 120 min. The results of modeling showed that the relative impact of RH on the infection risk depended on the ventilation rate and the size range of virus-laden droplets. A ventilation rate of 0.5 ACH, the change of RH between 20% and 53% was predicted to have a small effect on the infection risk, while at a ventilation rate of 6 ACH this change had nearly no effect. On the contrary, increasing the ventilation rate from 0.5 ACH to 6 ACH was predicted to decrease the infection risk by half which is remarkably larger effect compared with that predicted for RH. It is thus concluded that increasing the ventilation rate is more beneficial for reducing the airborne levels of SARS-CoV-2 than changing indoor RH.

PRACTICAL IMPLICATIONS

The present results show that humidification to moderate levels of 40%-60% RH should not be expected to provide a significant reduction in infection risk caused by SARS-CoV-2, hence installing and running humidifiers may not be an efficient solution to reduce the risk of COVID-19 disease in indoor spaces. The results do however confirm that ventilation has a key role in controlling SARS-CoV-2 virus concentration in the air providing considerably higher benefits. The modified model developed in the present work can be used by public health experts, engineers, and epidemiologists when selecting different measures to reduce the infection risk from SARS-CoV-2 indoors allowing informed decisions concerning indoor environmental control.

Influence of surgical team activity on airborne bacterial distribution in the operating room with a mixing ventilation system: a case study at St. Olavs Hospital

BACKGROUND

Operating rooms (ORs) have strict requirements regarding cleanliness. While existing standards concerning the ventilation and staff guidelines are theoretically sufficient to subvert the threats posed by micro-organisms within the room, there exist potential sources of contamination due to human activity around the area. Studies exploring this influence of human activity on distribution of micro-organism contamination in ORs have relied on manual observations, or indirect methods such as number of door openings.

AIM

To utilize depth registration sensing technology to identify the activities of surgical staff and investigate their effect on the distribution of airborne micro-organism contamination in ORs.

METHODS

A mock surgical experiment was performed using a depth registration technique for the dynamic capturing of human presence and activity levels. Field measurements were carried out in one real OR to analyse its influence on the bacterial distribution in ORs with mixing ventilation system.

FINDINGS

Bacterial contamination levels tended to correlate with higher activity levels, albeit with some inconsistencies. The highest activity levels were around the surgical bed when the patient was placed, and around the instrument table during the surgical procedure. Locations with obstructions had the highest cfu densities, indicating that airflow patterns are important in such spaces.

CONCLUSION

Our activity monitoring methods demonstrate a novel means of studying the influences of human activities in hospital rooms.

[Screening and analysis of Treponema pallidum specific antibody among childbearing age people in rural areas of Yunnan province, 2013-2017]

Objective: To determine the prevalence, epidemiological characteristics, and related factors of syphilis infection among rural childbearing age people to promote medical interventions on pre-pregnancy aristogenesis and syphilis infection in Yunnan province. Methods: The subjects in this study were 18-49-year-old rural couples of childbearing age from the National Free Preconception Health Examination Project in Yunnan province during 2013-2017. The descriptive study was carried out to determine the positive rate of Treponema pallidum specific antibody (TPsAb) and related sociodemographic characteristics. Results: The overall positive rate of TPsAb was 0.38% (8 204/2 160 455) in 2 160 455 rural childbearing age people in Yunnan. The positive rate of TPsAb was 0.39% (4 019/1 040 981) in men,higher than that in women (0.37%,4 185/1 119 474). The positive rate of TPsAb was highest in the age group 45-49 years (0.70%,158/22 511). The positive rate of TP antibody in the minority ethnic groups and Han ethnic groups appeared the same (0.38%). However,the highest positive rate of TPsAb was 0.77% (461/60 153) in Hani ethnic group among all the 17 minority ethnic groups. People with education level of primary education had the highest anti-TP positive rate (0.54%,2 327/431 275). The positive rate of TPsAb appeared the highest in Zhaotong (0.73%, 2 049/281 614) area among all the 16 prefectures of the province. The positive rate of TPsAb in the population from the impoverished regions (0.50%,2 963/590 039) was higher than in other disadvantaged areas (0.34%, 3 115/929 368) or areas with average income (0.33%,2 126/641 048). Significant differences appeared in the positive rate of TPsAb among populations of different ages, ethnic, education level, and economic level groups (trend χ² test, P<0.001). Conclusions: The positive rate of TP antibody in rural childbearing age people in Yunnan was related to multi factors,including sex,age,ethnic group,education level,area, residence, and local economic situation. The positive rate of TPsAb was higher in men than in women. And people with elder age, lower education level, being Hani or Lahu ethnic group, and Zhaotong areas had higher TPsAb positive rates and higher syphilis infection risk.

[Preliminary efficacy and safety analysis of carrelizumab combined with apatinib in patients with middle-advanced liver cancer progressed after drug-eluting beads-transcatheter arterial chemoembolization]

Objective: To explore the preliminary clinical efficacy and safety of calerizumab combined with apatinib in the treatment of patients with middle-advanced liver cancer whose disease has progressed after drug-eluting beads-transcatheter arterial chemoembolization (D-TACE). Methods: A retrospective analysis of 23 patients with advanced liver cancer after D-TACE who were treated with carrelizumab combined with apatinib from April 2019 to July 2020 at Lianyungang First People's Hospital was carried out. There were 15 males and 8 females with a mean age of (62±9) years. The clinical efficacy was evaluated according to the modified Response Evaluation Criteria in Solid Tumors (mRECRST), and treatment-related adverse events were analyzed after treatment. Results: All the patients received D-TACE therapy with an average of (2.6±1.0) times, TACE-refractory tumor was observed in 7 patients, and distant metastasis was seen in 6 patients. The objective response rates after combined treatment of 1 month and 3 months were 47.8% and 60.9%, respectively. Disease control rate (DCR) was 73.9% and 78.3%, respectively; median progression-free survival (mPFS) was 126 days. Among 18 patients with alpha fatoprotein (AFP)>200 μg/L, the values before and after treatment of 2 months was (497±117) μg/L and (80±19) μg/L, respectively (P<0.05). Among 9 patients of vascular endothelial growth factor (VEGF)>142.2 ng/L, the values before and after treatment of 2 months was (154±51) ng/L and (57±19) ng/L, respectively (P<0.05). The incidence of treatment-related adverse events was 87.0% (20/23). All adverse reactions did not exceed grade 3 and could be controlled by symptomatic supportive treatment or reducing the dose of apatinib,and the serum aspartate aminotransferase (AST) level after treatment of 3 months[(77±33) U/L] was higher than that before treatment [(45±26) U/L] (P<0.05). Conclusion: For patients with advanced liver cancer after D-TACE, the treatment of carrelizumab combined with apatinib is effective and the adverse reactions are controllable.

Thymosin beta-4 prenatal administration improves fetal development and halts side effects due to preterm delivery

OBJECTIVE

Thymosin beta 4 (TB4) is the most abundant member of the beta-thymosin family in humans. The main physiological role of TB4 is the regulation of actin polymerization. TB4 is also involved in angiogenesis, cell survival, cell migration and fetal development. The aim of this study was to evaluate the activity of TB4 as a fetal growth promoter when administered during pregnancy.

MATERIALS AND METHODS

Our protocols have been carried out in full conformity with the rules and guidelines expected for this kind of trial. 10 pregnant mice received the same injection regimen. Only 6 of these 10 are part of this experiment because they were pregnant. At 10:00 a.m. on day E14 and E17 of gestation mice were weighed and treated with an intraperitoneal injection of TB4 (Regene RX, Rockville, MD, USA; 6 mg/kg in PBS).

RESULTS

The mothers treated with TB4 for two days precisely E14 and E17, showed a higher cranio-caudal length when compared to control newborns. At histology, maternal TB4 treatment was associated with more advanced development of lungs, heart, kidney, cerebral cortex and notochord.

CONCLUSIONS

Our study shows that TB4 administration during gestation may act as a powerful fetal growth promoter, by accelerating the development of newborn organs and tissues.

The investigation of the influence of thermal plume and breathing on sleeping microenvironment

Most of humans' lifetime was spent indoor, especially in bedroom. Thus, understanding the characteristics of the sleep microenvironment is a prerequisite for better control and improvement of our sleeping environment. This study investigated the temperature and velocity field above the heads of sleeping people with supine postures, and explored the interactions between the thermal plume and the breathing airflow, where both the thermal manikins and real human subjects were used in our experiment settings. Three different breathing modes were considered in this study, where the non-breathing mode was used to investigate the characteristics of the thermal plume, and the synergy of the mouth and nose breathing mode on the thermal plume was also investigated. The results showed that the thermal plume of a supine posture person was not strong compared to that of a standing or sitting person, and the breathing airflow could influence the development of the thermal plume. Over the head of a sleeping person, the velocity of the thermal plume could be increased by both of the breathing modes, but no significant difference in the velocity and temperature field was found for the two breathing modes. It was also found that pollutants near the bed surface could be brought to the breathing zone with low velocity airflow, but could be blocked by the nasal exhalation jet. The findings in this study could provide theoretical support and guidance to improve the air quality in the breathing zone.

Experimental and simulated evaluations of airborne contaminant exposure in a room with a modified localized laminar airflow system

The traditional mixing ventilation is not an energy effective approach to remove indoor air pollutants, maintain breath zone air quality, and control the airborne transmission. This study investigated the potential of a localized laminar airflow ventilation system to alleviate human exposure to pollutants. Breathing thermal manikins with sitting posture and supine posture were used to simulate the human. N₂O was used as the tracer gas to simulate the indoor pollutant emission. The contaminant exposure index (ε_exp) and intake fraction index (IF) were used to assess the risk of human pollutant exposure for various supply air velocities given different emission source positions. Enhanced pollutant removal efficiency (E_ff) (from the result) showed the qualification and desirability of the localized laminar airflow ventilation system in improving the breath zone air quality. The results showed that the CFD results could fit well with the experimental data and found out the interaction between thermal plume and supply air. The results also indicated a low ε_exp and IF, with over 90%, all of which were highly correlated with the supply velocity. Human's different breathing methods have little influence on the pollutant exposure so as to the location of the pollution source. This study found that localized laminar airflow ventilation system could efficiently provide fresh air to the breathing zone without sacrificing the thermal environment around human. It can be used for small region air quality control such as that in the bedroom and living room where desired air quality is favored.

Ventilation design conditions associated with airborne bacteria levels within the wound area during surgical procedures: a systematic review

BACKGROUND

Without confirmation of the ventilation design conditions (typology and airflow rate), the common practice of identifying unidirectional airflow (UDAF) systems as equivalent to ultra-clean air ventilation systems may be misleading, but also any claims about the ineffectiveness of UDAF systems should be doubted. The aim of this review was to assess and compare ventilation system design conditions for which ultra-clean air (mean <10 cfu/m³) within 50 cm from the wound has been reported. Six medical databases were systematically searched to identify and select studies reporting intraoperative airborne levels expressed as cfu/m³ close to the wound site, and ventilation system design conditions. Available data on confounding factors such as the number of persons present in the operating room, number of door openings, and clothing material were also included. Predictors for achieving mean airborne bacteria levels within <10 cfu/m³ were identified using a penalized multivariate logistic regression model. Twelve studies met the eligibility criteria and were included for analysis. UDAF systems considered had significantly higher air volume flows compared with turbulent ventilation (TV) systems considered. Ultra-clean environments were reported in all UDAF-ventilated (N = 7) rooms compared with four of 11 operating rooms equipped with TV. On multivariate analysis, the total number of air exchange rates (P=0.019; odds ratio (OR) 95% confidence interval (CI): 0.66-0.96) and type of clothing material (P=0.031; OR 95% CI: 0.01-0.71) were significantly associated with achieving mean levels of airborne bacteria <10 cfu/m³. High-volume UDAF systems complying with DIN 1946-4:2008 standards for the airflow rate and ceiling diffuser size unconditionally achieve ultra-clean air close to the wound site. In conclusion, the studied articles demonstrate that high-volume UDAF systems perform as ultra-clean air systems and are superior to TV systems in reducing airborne bacteria levels close to the wound site.

Enhancement of the spin-orbit coupling by strong electronic correlations in transition metal and light actinide compounds

A simple variational argument is presented which indicates that the spin-orbit coupling in itinerant systems can be enhanced by strong electronic correlations. The importance of the enhancement in the formation of the giant magnetic anisotropy found in the metallic paramagnetic and magnetically ordered states of compounds containing transition metal and light actinide elements (such as tetragonal Sr2RhO4, Sr2IrO4, the cubic uranium monochalcogenides and tetragonal URu2Si2) is discussed.

The role of hsa_circ_0000285 in metastasis of hepatocellular carcinoma

Since this article has been suspected of research misconduct and the corresponding authors did not respond to our request to prove originality of data and figures, "The role of hsa_circ_0000285 in metastasis of hepatocellular carcinoma, by X.-J. Zhang, G. Cao, J. Fu, H.-J. Zhuang, J. Shi, published in Eur Rev Med Pharmacol Sci 2020; 24 (7): 3579-3585-DOI: 10.26355/eurrev_202004_20819-PMID: 32329832" has been withdrawn. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/20819.

Can CO2 sensors in the ventilation system of a pool facility help reduce the variability in the trihalomethane concentration observed in indoor air?

Volatile and hazardous compounds are formed during the chlorination of pool water. Monitoring components in the air, such as the four trihalomethanes; chloroform, dichlorobromomethane, dibromochloromethane and bromoform (tTHM), is challenging. Carbon dioxide (CO₂) sensors are used for controlling air quality in different buildings and can be installed in ventilation systems for continuous surveillance and monitoring purposes. However, such sensors are not used in indoor swimming facilities. In this study, samples of tTHM and CO₂ were collected and analysed, along with other air and water quality parameters such as combined chlorine, to evaluate whether CO₂ sensors could be used to explain the observed variability in the tTHM concentration in an indoor swimming facility and thereby reduce the exposure of individuals utilising the pool to tTHM. Random intercept models were built for the tTHM and CO₂ concentrations, respectively, and the results show that the relationships between combined chlorine in the water, CO₂ in the air and number of occupants explain 52% of the variability in tTHM. The correlation between occupancy and CO₂ concentration (ρ = 0.65, p ≤ 0.01) suggests that CO₂ sensors should be used so that the air supply corresponds to the demand of the users.

The role of hsa_circ_0000285 in metastasis of hepatocellular carcinoma

OBJECTIVE

The importance of circular RNAs in malignant tumors causes more attention in researchers. Hepatocellular carcinoma (HCC) is one of the most ordinary malignant tumors. Hsa_circ_0000285 was explored to identify how it functions in the metastasis of HCC.

PATIENTS AND METHODS

Real Time-quantitative Polymerase Chain Reaction (RT-qPCR) was utilized to detect hsa_circ_0000285 expression in HCC patients' tissues. Hsa_circ_0000285 lentivirus and shRNA was constructed for the transfection of HCC cells. Wound healing assay, transwell assay, and Matrigel assay were conducted to identify the function of hsa_circ_0000285 in HCC cells. Furthermore, mechanism assays were performed to uncover the interaction between hsa_circ_0000285 and miR-599.

RESULTS

Hsa_circ_0000285 was significantly higher-expressed in HCC samples compared to that in adjacent samples. The migrated length of HCC cells was reduced after hsa_circ_0000285 was silenced, while the migrated length of HCC cells was increased after hsa_circ_0000285 was overexpressed. Moreover, the number of migrated and invaded HCC cells was reduced after hsa_circ_0000285 was silenced, while the number of migrated and invaded HCC cells was increased after hsa_circ_0000285 was overexpressed. Moreover, RT-qPCR results revealed that miR-599 was downregulated via overexpression of hsa_circ_0000285, while miR-599 was upregulated via knockdown of hsa_circ_0000285. Further experiments showed that miR-599 was a direct target of hsa_circ_0000285 in HCC.

CONCLUSIONS

Hsa_circ_0000285 could enhance cell metastasis of HCC by targeting miR-599 and might be a potential therapeutic target in HCC.

Possible Quantum Paramagnetism in Compressed Sr_{2}IrO_{4}

The effect of compression on the magnetic ground state of Sr_{2}IrO_{4} is studied with x-ray resonant techniques in the diamond anvil cell. The weak interlayer exchange coupling between square-planar 2D IrO_{2} layers is readily modified upon compression, with a crossover between magnetic structures around 7 GPa mimicking the effect of an applied magnetic field at ambient pressure. Higher pressures drive an order-disorder magnetic phase transition with no magnetic order detected above 17-20 GPa. The persistence of strong exchange interactions between J_{eff}=1/2 magnetic moments within the insulating IrO_{2} layers up to at least 35 GPa points to a highly frustrated magnetic state in compressed Sr_{2}IrO_{4}, opening the door for realization of novel quantum paramagnetic phases driven by extended 5d orbitals with entangled spin and orbital degrees of freedom.

Type I renal tubular acidosis caused by Sjögren's syndrome with hypokalemia as the first symptom: a case report

Sjögren's syndrome is a chronic inflammatory autoimmune disease characterized by exocrine gland involvement and marked lymphocytic infiltration. Numerous reports of patients with Sjögren's syndrome have described kidney damage, mainly involving distal tubule dysfunction, severe renal calcification, kidney stones, and rickets. We herein describe a patient with primary Sjögren's syndrome who developed type I renal tubular acidosis with hypokalemia as the first symptom. This case highlights the possibility that an underlying autoimmune disorder should be considered in a patient presenting with distal tubular acidosis or recurrent hypokalemic periodic paralysis because treatment of the primary disease improves the outcome.

Microbial community succession and toxic alkaloids change during fermentation of Huafeng Dan Yaomu

Fermentation is a traditional processing method that can impact the abundance of relevant components in Chinese herbal medicines. Huafeng Dan Yaomu was processed by fermentation. In this study, we investigated changes in toxic alkaloids using high-performance liquid chromatography and analysed the changes in microbial communities during fermentation of Huafeng Dan Yaomu by Illumina MiSeq platform. The results indicated that highly toxic alkaloid compounds including aconitine, mesaconitine and hypaconitine were decreased, whereas benzoylmesaconine and benzoylhypaconitine were increased during fermentation. The dominant bacterial genera in the raw material (day 0) were Bacillus (58·38%), Enterobacter (16·05%), Enterococcus (4·10%) and others (11·48%). After 7 days of fermentation, Pediococcus predominated, increasing from 98·26 to 99·97%. The dominant fungal genera in the raw material (day 0) were Incertae_Sedis_incertae_sedis (45·36%), Eurotiales_unclassified (20·63%), Millerozyma (15·58%) and Saccharomycopsis (10·64%). After 7 days of fermentation, Saccharomycopsis was increased to 90·84%. After 14 days of fermentation, Pichia became the main fungal genera in the fermentation process. There were 16 bacterial genera and seven fungal genera that displayed significant correlation with toxic alkaloids. The dynamics of the microbiota and chemical compounds during fermentation of Huafeng Dan Yaomu were revealed, providing a foundation for further investigation of the effects of microbes on chemical compounds and insights into the manufacturing of Huafeng Dan Yaomu. SIGNIFICANCE AND IMPACT OF THE STUDY: Huafeng Dan Yaomu is a unique fermentation-based micro-organism product. This study reveals that the change in toxic alkaloids during fermentation was related to micro-organisms. The results of this study can be used to improve the Chinese herb medicine fermentation process, such as the selection of beneficial strains and their composition for modern fermentation. The results of this study may also provide new ideas for the processing of Traditional Chinese Medicine.

Laminar airflow and mixing ventilation: Which is better for operating room airflow distribution near an orthopedic surgical patient?

BACKGROUND

There has been little research on the performance of laminar airflow (LAF) and mixing ventilation (MV) systems regarding clean airflow distribution near a surgical patient in operating rooms (ORs). The objective of this study was to examine the performance of LAF and MV systems in ORs at St Olavs Hospital in Norway.

METHODS

Experimental measurements were conducted in 2 ORs equipped with LAF and MV systems.

RESULTS

Under real operating conditions, airflow distribution from the LAF system was disrupted, and airflow velocity became significantly lower than that of MV above the lying patient. Airflow pattern was observed as distributed vertically downward and horizontally with LAF and MV, respectively. Turbulence intensity of supply airflow from LAF was much lower than that of MV.

CONCLUSIONS

The airflow distribution by LAF system in close proximity to a patient is greatly affected by thermal plumes generated above incisions by both patients and surgical facilities. The effect of surgical facilities on airflow distribution by using MV is not significant compared to LAF ventilation. New guidelines are needed for the design of clean airflow distribution systems in the vicinity of surgical patients in ORs.

Direct Detection of Dimer Orbitals in Ba_{5}AlIr_{2}O_{11}

The electronic states of many Mott insulators, including iridates, are often conceptualized in terms of localized atomic states such as the famous "J_{eff}=1/2 state." Although orbital hybridization can strongly modify such states and dramatically change the electronic properties of materials, probing this process is highly challenging. In this Letter, we directly detect and quantify the formation of dimer orbitals in an iridate material Ba_{5}AlIr_{2}O_{11} using resonant inelastic x-ray scattering. Sharp peaks corresponding to the excitations of dimer orbitals are observed and analyzed by a combination of density functional theory calculations and theoretical simulations based on an Ir-Ir cluster model. Such partially delocalized dimer states lead to a redefinition of the angular momentum of the electrons and changes in the magnetic and electronic behaviors of the material. We use this to explain the reduction of the observed magnetic moment with respect to predictions based on atomic states. This study opens new directions to study dimerization in a large family of materials, including solids, heterostructures, molecules, and transient states.

Do surgeons and surgical facilities disturb the clean air distribution close to a surgical patient in an orthopedic operating room with laminar airflow?

BACKGROUND

Airflow distribution in the operating room plays an important role in ensuring a clean operating microenvironment and preventing surgical site infections (SSIs) caused by airborne contaminations. The objective of this study was to characterize the airflow distribution in proximity to a patient in an orthopedic operating room.

METHODS

Experimental measurements were conducted in a real operating room at St. Olav's Hospital, Norway, with a laminar airflow system. Omnidirectional anemometers were used to investigate the air distribution in the operating zone, and 4 different cases were examined with a real person and a thermal manikin.

RESULTS

This study showed that the downward airflow from the laminar airflow system varies in each case with different surgical arrangement, such as the position of the operating lamp. The results indicate that the interaction of thermal plumes from a patient and the downward laminar airflow may dominate the operating microenvironment.

CONCLUSIONS

The airflow distribution in proximity to a patient is influenced by both the surgical facility and the presence of medical staff. A thermal manikin may be an economical and practical way to study the interaction of thermal plumes and downward laminar airflow. The provision of higher clean airflow rate in the operating microenvironment may be an effective way to prevent the development of SSIs caused by indoor airborne contamination.

Signals in Stem Cell Differentiation on Fluorapatite-Modified Scaffolds

Previously, we reported that the fluorapatite (FA)-modified polycaprolactone (PCL) nanofiber could be an odontogenic/osteogenic inductive tissue-engineering scaffold by inducing stem cell differentiation and mineralization. The present study aimed to explore which of the signal pathways affected this differentiation and mineralization process. The Human Signal Transduction PathwayFinder RT² Profiler PCR Array was used to analyze the involvement of potential signal transduction pathways during human dental pulp stem cell (DPSCs) osteogenic differentiation induced by FA-modified PCL nanofiber scaffolds. Based on the results, perturbation studies of the signaling pathways hedgehog, insulin, and Wnt were performed. Moreover, the autophagy process was studied, as indicated by the expression of the microtubule-associated protein 1 light chain 3A/B-II (LC3-II) and the cell osteogenic phenotypic changes. In a comparison of the cells grown on PCL + FA scaffolds and those on PCL-only scaffolds, the transcript expression of BMP2, BMP4, FOXA2, PTCH1, WNT1, and WNT2 (PCR array-labeled signal proteins of the hedgehog pathway); CEBPB, FASN, and HK2 (PCR array-labeled signal proteins of the insulin pathway); and CCND1, JUN, MYC, TCF7, and WISP1 (PCR array-labeled signal proteins of the Wnt pathway) doubled at day 14 when obvious cell osteogenic differentiation occurred. Phenotypically, in all the perturbation groups at day 14, ALP activity, OPN, and autophagy marker LC3-II expression were coincidently decreased. Consistently, no positive alizarin red staining or von Kossa staining was observed in the specimens from these perturbation groups at day 28. The results showed that when obvious cell differentiation occurred at day 14 on PCL + FA control groups, the inhibition of the hedgehog, insulin, and Wnt pathways significantly decreased DPSC osteogenic differentiation and mineralization. The osteogenic differentiation of DPSCs grown on FA-modified PCL scaffolds appeared to be positively modulated by the hedgehog, insulin, and Wnt signal pathways, which were coordinated with and/or mediated by the cell autophagy process.

Simulation and Experiment on Droplet Formation and Separation for Needle-Type Micro-Liquid Jetting Dispenser

The needle-type droplet jetting dispenser has wide applications in the field of microelectronic packaging, and for which the good quality of droplet formation and separation is the key to successful dispensing. This paper simulates the droplet jetting process which has been divided into 5 stages named backflow, growth, droplet extension, breakage, and separation, and analyses the combined effects of system parameters, such as pressure, viscosity, needle stroke, and nozzle diameter, on the changes of morphologies of ejected droplets, which is verified by experiments. The simulation and experiment results show that a higher driving pressure is quite suitable for the high-viscosity liquid to form normal droplets by avoiding adhesion. When increasing the needle stroke, the pressure should also be lowered properly to prevent the flow-stream. Besides, the nozzle with a large diameter is much more likely to cause sputtering or satellite-droplet problems. The results have a great significance for guiding the parameter settings of the needle-type dispensing approach.

Decoupling of magnetism and electric transport in single-crystal (Sr1-x A x )2IrO4 (A = Ca or Ba)

We report a systematical structural, transport and magnetic study of Ca or Ba doped Sr₂IrO₄ single crystals. Isoelectronically substituting Ca²⁺ (up to 15%) or Ba²⁺ (up to 4%) ion for the Sr²⁺ ion provides no additional charge carriers but effectively changes the lattice parameters in Sr₂IrO₄. In particular, 15% Ca doping considerably reduces the c-axis and the unit cell by nearly 0.45% and 1.00%, respectively. These significant, anisotropic compressions in the lattice parameters conspicuously cause no change in the Néel temperature which remains at 240 K, but drastically reduces the electrical resistivity by up to five orders of magnitude or even precipitates a sharp insulator-to-metal transition at lower temperatures, i.e. the vanishing insulating state accompanies an unchanged Néel temperature in (Sr_1-x A _x )₂IrO₄. This observation brings to light an intriguing difference between chemical pressure and applied pressure, the latter of which does suppress the long-range magnetic order in Sr₂IrO₄. This difference reveals the importance of the Ir1-O2-Ir1 bond angle and homogenous volume compression in determining the magnetic ground state. All results, along with a comparison drawn with results of Tb and La doped Sr₂IrO₄, underscore that the magnetic transition plays a nonessential role in the formation of the charge gap in the spin-orbit-tuned iridate.

Molecular characterization and expression patterns of ghrelin in the reindeer (Rangifer tarandus)

Ghrelin is a novel growth hormone (GH)-releasing peptide, which has been identified as an endogenous ligand for the GH-sretagogue receptor. The sequence and expression of ghrelin has been determined in many species. In this study, to reveal the molecular characterization and expression patterns of ghrelin in the reindeer (Rangifer tarandus), the full-length DNA and cDNA encoding ghrelin were cloned from reindeer stomach using genome walking and rapid amplification of complementary deoxyribonucleic acid ends (RACE). The expression of ghrelin in almost all tissues was examined by real-time quantitative PCR (RT-qPCR). The 4076 bp amplicon of the ghrelin gene consisting of 4 exons and 3 introns was cloned from reindeer. Results of cDNA cloning and sequence analysis revealed that the full-length ghrelin cDNA was composed of 539 bp that included a 5'-untranslated region (46 bp), an open reading frame (ORF) (351 bp), and a 3'-untranslated region (142 bp). In addition, ghrelin was expressed in the all tissues examined, with the expression in the abomasum significantly higher than that in other tissues (p<0.05), followed by the pancreas, duodenum, testis and oesophagus. The results show that the expression of ghrelin in the reindeer gastrointestinal tract is extensive, suggesting its may have a role in regulating the digestive function.

Electrical Control of Structural and Physical Properties via Strong Spin-Orbit Interactions in Sr_{2}IrO_{4}

Electrical control of structural and physical properties is a long-sought, but elusive goal of contemporary science and technology. We demonstrate that a combination of strong spin-orbit interactions (SOI) and a canted antiferromagnetic Mott state is sufficient to attain that goal. The antiferromagnetic insulator Sr_{2}IrO_{4} provides a model system in which strong SOI lock canted Ir magnetic moments to IrO_{6} octahedra, causing them to rigidly rotate together. A novel coupling between an applied electrical current and the canting angle reduces the Néel temperature and drives a large, nonlinear lattice expansion that closely tracks the magnetization, increases the electron mobility, and precipitates a unique resistive switching effect. Our observations open new avenues for understanding fundamental physics driven by strong SOI in condensed matter, and provide a new paradigm for functional materials and devices.

Dynamic interaction of a downward plane jet and a cough jet with respect to particle transmission: An analytical and experimental study

A cough jet can travel beyond the breathing zone of the source person, and thus, infectious viral- and bacterial-laden particles can be transported from the source person to others in close proximity. To reduce the interpersonal transmission of coughed particles, the objective of this study was to analytically and experimentally investigate the performance of downward plane jets with various discharge velocities. Chamber measurements were conducted to examine the interaction between a transient cough jet (discharge velocities of 12 m/sec and 16 m/sec) and a steady downward plane jet (discharge velocities from 1.0-8.5 m/sec) with respect to the transport of and human exposure to coughed particles. The results show that a relatively high-speed cough can easily penetrate a downward plane jet with a discharge velocity of less than 6 m/sec. A downward plane jet with a discharge velocity of 8.5 m/sec can bend the cough jet to a certain extent. In this study, momentum comparison of the cough jet and the downward plane jet shows that the value of personal exposure to coughed particles depends on the ratio of jet momentums. The results show that when the two momentums are equivalent or if the downward plane jet has a greater momentum, the cough jet is deflected downward and does not reach the breathing zone of the target thermal dummy. Using the ratio of the two momentums, it may be estimated whether the transmission of a cough jet can be controlled. A trajectory model was developed based on the ratio of the two momentums of a cough jet and a downward jet and was validated using the experimental data. In addition, the predicted trajectory of the cough jet agreed well with the results from smoke visualization experiments. This model can be used to guide the design of downward plane jet systems for protection of occupants from coughed particles.

Left ventricular hypertrophy does not prevent heart failure in experimental hypertension

BACKGROUND

Left ventricular hypertrophy (LVH) secondary to hypertension has been accepted to prevent heart failure (HF) while paradoxically increasing cardiovascular morbi-mortality.

OBJECTIVES

To evaluate whether antihypertensive treatment inhibits LVH, restores beta-adrenergic response and affects myocardial oxidative metabolism.

METHODS

Ninety spontaneously hypertensive rats (SHR) were distributed into groups and treated (mg/kg, p.o.) with: losartan 30 (L), hydralazine 11 (H), rosuvastatin 10 (R), carvedilol 20 (C). Hypertension control group comprised 18 normotensive rats (Wistar-Kyoto, WKY). Following euthanasia at 16months, contractility was measured in 50% of rats (Langendorff system) before and after isoproterenol (Iso) 10^-9M, 10^-7M and 10^-5M stimulation. Left ventricular weight (LVW) was measured in the remaining hearts, and normalized by BW. Expression of thioredoxin 1 (Trx-1), peroxyredoxin 2 (Prx-2), glutaredoxin 3 (Grx-3), caspase-3 and brain natriuretic peptide (BNP) was determined.

RESULTS

Systolic blood pressure (mmHg): 154±3 (L), 137±1 (H), 190±3 (R)*, 206±3 (SHR)*, 183±1 (C)**, and 141±1 (WKY) (*p<0.05 vs. L, H, WKY, **p<0.05 vs. L, H, WKY, SHR). LVW/BW was higher in SHR and R (p<0.05). Groups SHR, R and C evidenced baseline contractile depression. Response to Iso 10^-5M was similar in WKY and L. Expression of Trx-1, Prx-2 and Grx-3 increased in C, H, R and L (p<0.01).

CONCLUSIONS

Present findings argue against the traditional idea and support that LVH might not be required to prevent HF. Increased expression of thioredoxins by antihypertensive treatment might be involved in protection from HF.

Dark Matter Search Results from the PICO-60 C_{3}F_{8} Bubble Chamber

New results are reported from the operation of the PICO-60 dark matter detector, a bubble chamber filled with 52 kg of C_{3}F_{8} located in the SNOLAB underground laboratory. As in previous PICO bubble chambers, PICO-60 C_{3}F_{8} exhibits excellent electron recoil and alpha decay rejection, and the observed multiple-scattering neutron rate indicates a single-scatter neutron background of less than one event per month. A blind analysis of an efficiency-corrected 1167-kg day exposure at a 3.3-keV thermodynamic threshold reveals no single-scattering nuclear recoil candidates, consistent with the predicted background. These results set the most stringent direct-detection constraint to date on the weakly interacting massive particle (WIMP)-proton spin-dependent cross section at 3.4×10^{-41}  cm^{2} for a 30-GeV c^{-2} WIMP, more than 1 order of magnitude improvement from previous PICO results.