C1 gases including CO, CO₂ and CH₄, are mainly derived from terrestrial biological activities, industrial waste gas and gasification syngas. Particularly, CO₂ and CH₄ are two of the most important greenhouse gases contributing to climate change. Bioconversion of C1 gases is not only a promising solution to addressing the problem of waste gases emission, but also a novel route to produce fuels or chemicals. In the past few years, C1-gas-utilizing microorganisms have drawn much attention and a variety of gene-editing technologies have been applied to improve their product yields or to expand product portfolios. This article reviewed the biological characteristics, aerobic or anaerobic metabolic pathways as well as the metabolic products of methanotrophs, autotrophic acetogens, and carboxydotrophic bacteria. In addition, gene-editing technologies (e.g. gene interruption technology using homologous recombination, group Ⅱ intron ClosTron technology, CRISPR/Cas gene editing and phage recombinase-mediated efficient integration of large DNA fragments) and their application in these C1-gas-utilizing microorganisms were also summarized.
Gene Editing ; Gases ; Carbon Dioxide ; Genetic Engineering ; Cloning, Molecular

The current linear economy model relies on fossil energy and increases CO₂ emissions, which contributes to global warming and environmental pollution. Therefore, there is an urgent need to develop and deploy technologies for carbon capture and utilization to establish a circular economy. The use of acetogens for C1-gas (CO and CO₂) conversion is a promising technology due to high metabolic flexibility, product selectivity, and diversity of the products including chemicals and fuels. This review focuses on the physiological and metabolic mechanisms, genetic and metabolic engineering modifications, fermentation process optimization, and carbon atom economy in the process of C1-gas conversion by acetogens, with the aim to facilitate the industrial scale-up and carbon negative production through acetogen gas fermentation.
Fermentation ; Gases/metabolism* ; Carbon Dioxide/metabolism* ; Metabolic Engineering ; Carbon/metabolism*

Objective: To examine the trend of the burden on chronic obstructive pulmonary diseases (COPD) and epidemiologic transition on related risk factors among the Chinese population from 1990 to 2019. Methods: Based on the data from the Global Burden of Disease 2019 Study, we used the indicator numbers such as disability-adjusted life year (DALY), years of life lost (YLD), years lived with disability (YLL), and prevalence rate to describe the changes of COPD burden stratified by different sex and age groups from 1990 to 2019. We applied population attribution faction (PAF) to analyze the burden attributed to risk factors and epidemiological transition. Results: In 2019, the age-standard rate for DALY, YLD, and YLL and prevalence rate for COPD were 1 102.77/100 000 population,862.37/100 000 population, 240.40/100 000 population, and 2 404.41/100 000. Both age-standardized DALY and YLL rates for COPD in males were higher than in females, except for the YLD rate in females. COPD's top five risk factors were particulate matter pollution, smoking, occupational particulate matter, gases, and fumes, low temperature, and secondhand smoke. Smoking surpassed environmental particulate pollution in 1994 and became the first factor causing the disease burden of COPD. Since then, the order of risk factors has not changed. The PAF of environmental particulate pollutants increased by 1.78% annually, from 15.22% in 1990 to 25.37%, and the PAF of household air pollution from solid fuels decreased by 5.59% annually, from 40.30% in 1990 to 7.59%. Conclusions: From 1990 to 2019, the per person health loss caused by COPD in China showed an overall downward trend. The PAF of relevant risk factors has also changed, the importance of environmental factors is relatively declined, and the status of smoking and other related risk behaviors has become increasingly prominent. The prevention and control of COPD can focus on screening high-risk groups (≥40 years old, smoking, heavy air pollution, having occupational exposure), smoking cessation, and environmental treatment.
Female ; Male ; Humans ; Adult ; Cost of Illness ; Pulmonary Disease, Chronic Obstructive/epidemiology* ; Air Pollution/adverse effects* ; Particulate Matter ; China/epidemiology* ; Dust ; Gases

As a convenient and effective surface modification approach, non-thermal atmospheric pressure plasma (NTAPP)can be used to improve dentin bonding, and has recently become a research focus. Studies have shown that NTAPP can alter dentin surface properties, improve the penetration and polymerization of adhesives, stimulate the cross-linking of collagen, and change the micro-morphology and element content of dentin surface, thus improve the dentin bonding quality. This article introduces the current research progress in the application of NTAPP in the field of dentin bonding, in order to provide innovative information for future research in optimization of the quality of dentin bonding.
Dental Bonding ; Dental Cements ; Dentin ; Dentin-Bonding Agents ; Materials Testing ; Plasma Gases ; Resin Cements ; Surface Properties

Objective: To explore the occupational hazards caused by three kinds of welding operations, and to provide data support for individual protection. Methods: In October 2020, the welding fumes, metal elements and welding arc generated by three welding operations of argon gas shielded welding (JS80 welding wire) , manual welding (ZS60A welding rod) and carbon dioxide shielded welding (907A flux cored wire) were collected and measured in the welding laboratory. The samples were analyze and compare in the laboratory, and the differences of the occupational hazard factors of the three welding operations were judged. Results: The concentration of welding fume produced by carbon dioxide shielded welding, manual welding (ZS60A electrode) , and argon gas shielded welding (JS80 welding wires) were 6.80 mg/m(3), 6.17 mg/m(3), and 3.13 mg/m(3), respectively. The effective irradiance of the welding arc outside the welding mask from high to low is manual welding (ZS60A electrode) , carbon dioxide shielded welding (907A flux-cored welding wire) , and argon shielded welding (JS80 welding wire) , respectively 1 010.7, 740.9, 589.5 μW/cm(2). The long-wave ultraviolet UVA intensity generated by argon shielded welding (JS80 welding wire) is the largest, which is 1 500 μW/cm(2). The content of Mn in the three welding operations is the highest, and JS80 welding wire has the highest Mn content of 128493.2 mg/kg. 907A flux cored wire has the highest Ti content, which is 24355.5mg/kg. The electrode ZS60A has the highest Cu content, which is 24422.12 mg/kg. Conclusion: The intensity of occupational hazards is different in the three kinds of welding operations, so the methods of personal protective equipment, field exposure assessment and health monitoring should be more targeted.
Air Pollutants, Occupational/analysis* ; Argon/analysis* ; Carbon Dioxide/analysis* ; Gases/analysis* ; Occupational Exposure/analysis* ; Welding/methods*

Objective To determine the relationship between air pollutants [SO
Acne Vulgaris ; Air Pollution/adverse effects* ; China/epidemiology* ; Environmental Pollutants ; Female ; Gases ; Humans ; Male ; Outpatients

BACKGROUND: General anesthesia with intravenous or inhalation anesthetics reduces respiratory functions. We investigated the effects of propofol, desflurane, and sevoflurane on postoperative respiratory function tests.METHODS: This single-center randomized controlled study was performed in a university hospital from October 2015 to February 2017. Ninety patients scheduled for endoscopic endonasal transsphenoidal pituitary surgery were randomly categorized into either of these three groups: propofol (n = 30, the Group TIVA), desflurane (n = 30, the Group D) or sevoflurane (n = 30, the Group S). We analyzed the patients before, after, and 24 h following surgery, to identify the following parameters: forced expiratory volume in 1 second (FEV₁) %, forced vital capacity (FVC) %, FEV₁/FVC, and arterial blood gases (ABG). Furthermore, we also recorded the intraoperative dynamic lung compliance and airway resistance values.RESULTS: We did not find any significant differences in FEV₁ values (primary outcome) among the groups (P = 0.336). There was a remarkable reduction in the FEV₁ and FVC values in all groups postoperatively relative to the baseline (P < 0.001). The FVC, FEV₁/FVC, ABG analysis, compliance, and airway resistance were similar among the groups. Intraoperative dynamic compliance values were lower at the 1st and 2nd hours than those immediately after intubation (P < 0.001).CONCLUSIONS: We demonstrated that propofol, desflurane, and sevoflurane reduced FEV₁ and FVC values postoperatively, without any significant differences among the drugs.
Airway Resistance ; Anesthesia, General ; Anesthetics, Inhalation ; Compliance ; Forced Expiratory Volume ; Gases ; Humans ; Intubation ; Lung Compliance ; Propofol ; Prospective Studies ; Respiratory Function Tests ; Vital Capacity

PURPOSE: Direct application of atmospheric-pressure plasma jets (APPJs) has been established as an effective method of microbial decontamination. This study aimed to investigate the bactericidal effect of direct application of an APPJ using helium gas (He-APPJ) on Porphyromonas gingivalis biofilms on sandblasted and acid-etched (SLA) titanium discs. METHODS: On the SLA discs covered by P. gingivalis biofilms, an APPJ with helium (He) as a discharge gas was applied at 3 different time intervals (0, 3, and 5 minutes). To evaluate the effect of the plasma itself, the He gas–only group was used as the control group. The bactericidal effect of the He-APPJ was determined by the number of colony-forming units. Bacterial viability was observed by confocal laser scanning microscopy (CLSM), and bacterial morphology was examined by scanning electron microscopy (SEM). RESULTS: As the plasma treatment time increased, the amount of P. gingivalis decreased, and the difference was statistically significant. In the SEM images, compared to the control group, the bacterial biofilm structure on SLA discs treated by the He-APPJ for more than 3 minutes was destroyed. In addition, the CLSM images showed consistent results. Even in sites distant from the area of direct He-APPJ exposure, decontamination effects were observed in both SEM and CLSM images. CONCLUSIONS: He-APPJ application was effective in removing P. gingivalis biofilm on SLA titanium discs in an in vitro experiment.
Bacterial Load ; Biofilms ; Decontamination ; Helium ; In Vitro Techniques ; Methods ; Microbial Viability ; Microscopy, Confocal ; Microscopy, Electron, Scanning ; Plasma Gases ; Plasma ; Porphyromonas gingivalis ; Porphyromonas ; Stem Cells ; Titanium

OBJECTIVE: To investigate the effect of different treatment temperatures of a novel cold atmospheric plasma jet treatment on the resin-dentin bonding. METHODS: (1) Fifty-two freshly extracted, non-carious and intact third molars were collected. The occlusal one-third of the crown was removed by means of a water-cooled low-speed Isomet saw. One dentin disc [(900 ±100) μm] was prepared for each tooth. The fifty-two dentin discs were randomly divided into control group and experimental groups, of which four were in control group, and forty-eight were divided into four experimental groups according to the different treatment temperatures (4 °C, 10 °C, 20 °C and 30 °C) of the novel radio-frequency atmospheric-pressure glow discharge (RF-APGD) plasma jet, twelve in each group. Each experimental group was divided into three subgroups according to different treatment time (10 s, 20 s and 30 s), with four in each subgroup. The occlusal one-third of the crown was removed by means of a water-cooled low-speed Isomet saw. The morphology of demineralized dentin surfaces was analyzed using field emission scanning electron microscopy. (2) Twenty unerupted, non-carious and intact third molars were randomly divided into five groups, four in each group: control group, untreated; 4 °C, 10 °C, 20 °C and 30 °C experimental groups, each group was treated with the RF-APGD plasma jet for 20 s. The micro-tensile resin dentin bond strength was tested after 20 s RF-APGD plasma jet treatment with different temperatures, using a universal mechanical machine. RESULTS: (1) The field emission scanning electron microscopy results indicated that when compared with the control group, a 10 s RF-APGD plasma jet treatment with 30 °C and 20 °C collapsed the collagen scaffold. Collagen fibrils maintained an uncollapsed three-dimensional structure after the 4 °C RF-APGD plasma jet treatment for even 30 s treatment. (2) The microtensile resin dentin bond strength results of the 4 °C RF-APGD plasma jet treatment group (57.8±0.7) MPa were significantly higher than that of the control group [(47.4±0.5) MPa] and 10 s, 20 s and 30 s RF-APGD plasma treatment group [(51.9±0.7) MPa,(29.7±1.0) MPa and (22.2±1.5) MPa] with statistically significant difference (P<0.05). Compared with the control group, the micro-tensile bond strength increased about 21.9% and 9.5% after 4 °C and 10 °C RF-APGD plasma jet treatment, respectively. CONCLUSION Compared with other treatment temperatures, this novel RF-APGD plasma jet treatment with the temperature of 4 °C can preserve the three-dimensional morphology of demineralized dentin better, and can improve the resin-dentin bonding.
Composite Resins ; Dental Bonding ; Dentin ; Dentin-Bonding Agents ; Materials Testing ; Microscopy, Electron, Scanning ; Plasma Gases ; Resin Cements ; Temperature ; Tensile Strength

Weather may alter the concentrations of pollens which can subsequently influence the occurrence of allergic diseases. Many studies have demonstrated that greenhouse gases increase pollen concentration. Daily fluctuations in the pollen concentration have to do with a variety of meteorological factors such as temperature, rainfall and sunshine amount; therefore, it is complicated. At least more than 10 weather elements that affect the concentration of pollen. Earlier pollination and rising pollen concentrations have been reported in many countries. Most studies have focused on analysis of their relationships with local meteorological and climatic factors. Observed pollen data at locations representing a wide range of geographic and climatic conditions should be analyzed statistically to identify pollination date, pollen season length, and annual mean and peak values of daily concentrations of pollen. The seasonal and regional variations of pollen have also been changed in South Korea with climate change. There were evaluated sensitization rate to pollen in South Korea since 1997. Sensitization rates for weed and tree pollens are increased in Korean children, especially with increasing pollen concentration of ragweed and Japanese hop. It has been demonstrated that urbanization correlate with the increasing pollen allergies. However, the effects of environmental change on allergic diseases have not yet been completely understood. Recently there have been many epidemiological studies on the relationship between allergic diseases and climate changes. Previous studies suggest that climate changes interact with and affect pollen allergy, which in turn increases the frequency and severity of allergic disease.
Ambrosia ; Asian Continental Ancestry Group ; Child ; Climate Change* ; Climate* ; Epidemiologic Studies ; Gases ; Humans ; Korea* ; Meteorological Concepts ; Pollen* ; Pollination ; Rhinitis, Allergic, Seasonal* ; Seasons ; Sunlight ; Trees ; Urbanization ; Weather