We are pleased to announce that Medical Gas Research is now being published with Medknow Publications! Medknow Publications is a part of Wolters Kluwer Health and is among the largest open access publishers worldwide with over 350 print and online journals. Medknow also provides immediate free access without charging for submission, processing, or publication of articles. This has allowed Medknow journals to have more than a half a million article downloads each month. In addition, Medical Gas Research will now be directly indexed in the Web of Science through the Emerging Sources Citation Index at the time of publication. The Emerging Sources Citation Index, launched by Thomson Reuters in November 2015, will add more high quality publications from emerging scientific fields to the Web of Science universe and will transfer qualified journals to the Science Citation Index Expanded each year. Medical Gas Research was first created in 2011 to provide a stage for researchers in both clinical medicine and basic sciences to communicate, exchange information, and publish articles relating to the medical gas family. The medical gas family is quite large and consists of oxygen, hydrogen, carbon monoxide, carbon dioxide, nitrogen, xenon, hydrogen sulfide, nitrous oxide, carbon disulfide, argon, helium, and other noble gases. Medical Gas Research was innovative since it was the first international journal that focused on medical gas research on the basic, clinical, and translational sciences levels such as anesthesiology, diving medicine, emergency medicine, pharmacology, physiology, and neuroscience (Zhang, 2011). A few years ago the goal of Medical Gas Research was to be at the forefront of leading the discussion on how medical gases can be practically applied and offer therapeutic options to numerous medical complications (Liu et al., 2011). The journal also aimed to cover technical and historical insights, as well as, ethical and social issues as it relates to the medical gas research field. Since then we have been privileged to share with the world over 120 publications relating to medical gases and their applications over those years. Last year we received and published articles ranging on a variety of topics such as the pharmacokinetics of chronic administration of xenon and argon gases (Katz et al., 2015), the potential of normobaric hyperoxia as a treatment for acute ischemic stroke (Weaver and Liu, 2015), and the effectiveness of clinical application of hyperbaric oxygen treatment in various diseases like traumatic brain injury and post traumatic stress disorder (Harch, 2015; Hu et al., 2015; Stoller, 2015; Yan et al., 2015). Also one article demonstrated that hyperbaric oxygen treatment was effective in reducing acute distal colitis in rats by down-regulating pro-inflammatory cytokines (Parra et al., 2015). The application of hydrogen sulfide as a medical gas was a popular topic of our publications last year as well. We published articles concerning hydrogen sulfide mitigating fatty liver by improving lipid metabolism in high-fat diet induced obese mice, as well as hydrogen sulfide treatment restoring perfusion to chronically ischemic tissue in a rat hind limb model (Langston and Toombs, 2015; Wu et al., 2015). In addition, another article showed that hydrogen sulfide releasing moieties in the compound ATB-346 were able to inhibit alveolar bone loss and inflammation in rats with ligature-induced periodontitis (Herrera et al., 2015). Another popular topic of our publications last year concerned hydrogen, the lightest and most abundant element (Dixon et al., 2013). One article that contributes to the translation of hydrogen treatment explored the concentration levels of super-saturated hydrogen administration via oral, intravenous drip infusion, and inhalation (Kurokawa et al., 2015). Another article from last year reviewed all the original molecular hydrogen studies in the field after the landmark article in Nature Medicine by Oshawa and colleagues in 2007 which ignited interests in hydrogen research (Ichihara et al., 2015). We also published an article that demonstrates molecular hydrogen as a potential therapeutic solution to male infertility, since hydrogen treatment was able to improve low sperm motility (Nakata et al., 2015). Today Medical Gas Research still has the goals of being a leader in the understanding of how medical gases can be employed as novel therapies as well as their expansion into everyday life. We hope that Medical Gas Research will continue to facilitate an open forum for physicians and researchers, along with providing an international stage in this exciting field for many years to come!
Physical plasma is one consequence of gas ionization, i.e. its dissociation of electrons and ions. If operated in ambient air containing oxygen and nitrogen, its high reactivity produces various reactive oxygen and nitrogen species (RONS) simultaneously. Technology leap innovations in the early 2010s facilitated the generation of gas plasmas aimed at clinics and operated at body temperature, enabling their potential use in medicine. In parallel, their high potency as antimicrobial agents was systematically discovered. In combination with first successful clinical trials, this led in 2013 to the clinical approval of first medical gas plasma devices in Europe for promoting the healing of chronic and infected wounds and ulcers in dermatology. While since then, thousands of patients have benefited from medical gas plasma therapy, only the appreciation of the critical role of gas plasma-derived RONS led to unraveling first fragments of the mechanistic basics of gas plasma-mediated biomedical effects. However, drawing the complete picture of effectors and effects is still challenging. This is because gas plasma-produced RONS not only show a great variety of dozens of types but also each of them having distinct spatio-temporal concentration profiles due to their specific half-lives and reactivity with other types of RONS as well as different types of (bio) molecules they can react with. However, this makes gas plasmas fascinating and highly versatile tools for biomolecular redox research, especially considering that the technical capacity of increasing and decreasing individual RONS types holds excellent potential for tailoring gas plasmas toward specific applications and disease therapies.
Publishing 13 papers and cited 45 times in total till June 2016, the 2015 issue of Medical Gas Research did its best to offer wide-range selected papers focusing on gas research that aim at improving human health. Of the six research papers, including three reviews, one study protocol and three commentary articles, an article from Wu et al. (2015) addressing the issue of nonalcoholic fatty liver disease with hydrogen sulfide (H2S) arouses our best interest. Acting as an endogenous signaling molecule in mammals, H2S is dysregulated at the process of disease and the protective effects of elevating H2S level in blood and tissue are still not enough for clinical transfer. In the study by Wu et al., by employing a stable C57BL/6 mouse model undergoing different fat diets, H2S or saline was administrated once a day for continuous 4 weeks. From the aspects of lipids accumulation and liver damage, the authors objectively represented the beneficial results of H2S using markers from fat accumulation, including triglyceride and total cholesterol accumulation and expression of fatty acid synthase and carnitine palmitoyltransferase-1, and elevated liver oxidative products including malondialdehyde, superoxide dismutase and glutathione peroxidase levels. All these self-explanatory results demonstrated that H2S could mitigate nonalcoholic fatty liver by improving lipid metabolism and antioxidants potential in mice. Another study by Katz et al. (2015) focused on gas pharmacokinetics of xenon and argon therapy. It is to say, pharmacokinetics models of human, rats and other mammals would be the last piece of missing puzzle before the bloom of the study of noble gas on human disease therapy. The authors offered absorption, distribution, metabolism and excretion features of these two gases and showed that there could be a residual dose of xenon in humans but not in small animals in the pre-clinical studies. Further studies are indispensable for optimizing the therapeutic amount of noble gases. Other research articles published in the 2015 issue of Medical Gas Research concentrated further on H2S and also on hyperbaric oxygen and molecular hydrogen. Langston and Toombs (2015) tried to determine a minimum does and schedule sufficient to restore perfusion in the rat hindlimb. And it turns out that intravenous infusion of 0.25 mg/kg sodium sulfide twice a day for at least 7 days was efficient to significantly enhance perfusion in ischemic hindlimb. Herrera et al. (2015) explored the effects of ATB-346, a H2S-releasing naproxen derivative, in rats with ligature-induced periodontitis. Their results provided the first evidence that the presence of H2S-releasing moiety in the ATB-346 compound structure not only inhibits bone loss and inflammation but also prevents the occurrence of deleterious effects. Parra et al. (2015) also added their results on hyperbaric oxygen research saying that hyperbaric oxygen attenuates the severity of acute distal colitis through the down-regulation of pro-inflammatory events. A latest study in this year addressed stimulation of human damaged sperm motility using hydrogen molecule (Nakata et al., 2015). Exposure sperms from patients with hydrogen molecule and forward motility and swim speed were measured. The authors expressed the idea that hydrogen molecular stimulates low sperm motility and considered it is a novel tool for male infertility treatments. In the review section of the journal, the most cited review stands on the beneficial biological effects and the underlying mechanisms of molecular hydrogen using comprehensive review of 321 original articles (Ichihara et al., 2015). Implied with three methods of administration including gastrointestinal absorption using hydrogen water, inhalation using hydrogen gas and intraperitoneal using hydrogen rich saline, hydrogen molecule has fabricated a net connecting 31 disease categories and even extending to plants. Desperately desired is the underlying mechanism of molecular hydrogen on these diseases. Ichihara et al. (2015) not only offered a comprehensive handbook of knowing which has been published, but also thoroughly summarized the molecular mechanism of hydrogen. Other two reviews discussed hyperbaric oxygen and normobaric hyperoxia (Weaver and Liu, 2015; Yan et al., 2015). Yan et al. (2015) summarized indication and contraindications of hyperbaric oxygen therapy (HBOT) and relevant clinical and preclinical progress, while Weaver and Liu (2015) considered normobaric oxygen a viable neuro-protective strategy for acute ischemic stroke after critically reviewing current literature. One study protocol presented by Kurokawa et al. (2015) invented hydrogen intake devices aiming at the use of hydrogen in patients conveniently and safely providing the changes in H2 concentration. Three commentary articles focused on different aspect of hyperbaric oxygen application. Harch (2015) refined the definition of HBOT and expanded it to gene therapy. He emphasized that comprehensively understanding HBOT as a combination of pressure and oxygen does-dependent gene therapy would illuminate controversial problem on dual effects of this method. Hu et al. (2015) tried to solve the problem on the effect of HBOT on post-concussion syndrome that remains controversial. Their best assumption goes to the process of doing the research and do believe future studies would add in more confidence of applying HBOT on post-concussion. Stoller (2015) commented that HBOT should be employed on anyone that truly need it as soon as possible and no more interference should stand in the middle of this beneficial action.
Research of medical gases is well established in Poland and has been marked with the foundation of several professional societies. Numerous academic centers including those dealing with hyperbaric and diving medicine conduct studies of medical gases, in vast majority supported with intramural funds. In general, Polish research of medical gases is very much clinical in nature, covering new applications and safety of medical gases in medicine; on the other hand there are several academic centers pursuing preclinical studies, and elaborating basic theories of gas physiology and mathematical modeling of gas exchange. What dominates is research dealing with oxygen and ozone as well as studies of anesthetic gases and their applications. Finally, several research directions involving noble gas, hydrogen and hydrogen sulfide for cell protection, only begin to gain recognition of basic scientists and clinicians. However, further developments require more monetary spending on research and clinical testing as well as formation of new collective bodies for coordinating efforts in this matter.
Medical gas is a large family including oxygen, hydrogen, carbon monoxide, carbon dioxide, nitrogen, xenon, hydrogen sulfide, nitrous oxide, carbon disulfide, argon, helium and other noble gases. These medical gases are used in various disciplines of both clinical medicine and basic science research including anesthesiology, hyperbaric oxygen medicine, diving medicine, internal medicine, emergency medicine, surgery, and many basic science subjects such as physiology, pharmacology, biochemistry, microbiology and neuroscience. Unfortunately, there is not even one journal dedicated to medical gas research at the basic, translational, or clinical sciences level; especially in the neurobiology or neuroscience fields let alone the other various medical fields. Therefore, I am thrilled to introduce this new journal named Medical Gas Research to you in this launching editorial.
Recent basic and clinical research has revealed that hydrogen is an important physiological regulatory factor with antioxidant, anti-inflammatory and anti-apoptotic protective effects on cells and organs. Therapeutic hydrogen has been applied by different delivery methods including straightforward inhalation, drinking hydrogen dissolved in water and injection with hydrogen-saturated saline. This review summarizes currently available data regarding the protective role of hydrogen, provides an outline of recent advances in research on the use of hydrogen as a therapeutic medical gas in diverse models of disease and discusses the feasibility of hydrogen as a therapeutic strategy. It is not an overstatement to say that hydrogen's impact on therapeutic and preventive medicine could be enormous in the future.
This report summarizes a brief description/history of the Hydrogen Research Meetings as well as key presentations/oral abstracts delivered in the most recent symposium. Additionally, we introduced 38 diseases and physiological states for which hydrogen exhibits beneficial effects.
Medical gases are pharmaceutical gaseous molecules which offer solutions to medical needs and include traditional gases, such as oxygen and nitrous oxide, as well as gases with recently discovered roles as biological messenger molecules, such as carbon monoxide, nitric oxide and hydrogen sulphide. Medical gas therapy is a relatively unexplored field of medicine; however, a recent increasing in the number of publications on medical gas therapies clearly indicate that there are significant opportunities for use of gases as therapeutic tools for a variety of disease conditions. In this article, we review the recent advances in research on medical gases with antioxidant properties and discuss their clinical applications and therapeutic properties.
BACKGROUND: Observational studies have shown improvement in patients with type 2 diabetes mellitus after bariatric surgery. METHODS: In this randomized, nonblinded, single-center trial, we evaluated the efficacy of intensive medical therapy alone versus medical therapy plus Roux-en-Y gastric bypass or sleeve gastrectomy in 150 obese patients with uncontrolled type 2 diabetes. The mean (±SD) age of the patients was 49±8 years, and 66% were women. The average glycated hemoglobin level was 9.2±1.5%. The primary end point was the proportion of patients with a glycated hemoglobin level of 6.0% or less 12 months after treatment. RESULTS: Of the 150 patients, 93% completed 12 months of follow-up. The proportion of patients with the primary end point was 12% (5 of 41 patients) in the medical-therapy group versus 42% (21 of 50 patients) in the gastric-bypass group (P=0.002) and 37% (18 of 49 patients) in the sleeve-gastrectomy group (P=0.008). Glycemic control improved in all three groups, with a mean glycated hemoglobin level of 7.5±1.8% in the medical-therapy group, 6.4±0.9% in the gastric-bypass group (P<0.001), and 6.6±1.0% in the sleeve-gastrectomy group (P=0.003). Weight loss was greater in the gastric-bypass group and sleeve-gastrectomy group (-29.4±9.0 kg and -25.1±8.5 kg, respectively) than in the medical-therapy group (-5.4±8.0 kg) (P<0.001 for both comparisons). The use of drugs to lower glucose, lipid, and blood-pressure levels decreased significantly after both surgical procedures but increased in patients receiving medical therapy only. The index for homeostasis model assessment of insulin resistance (HOMA-IR) improved significantly after bariatric surgery. Four patients underwent reoperation. There were no deaths or life-threatening complications. CONCLUSIONS: In obese patients with uncontrolled type 2 diabetes, 12 months of medical therapy plus bariatric surgery achieved glycemic control in significantly more patients than medical therapy alone. Further study will be necessary to assess the durability of these results. (Funded by Ethicon Endo-Surgery and others; ClinicalTrials.gov number, NCT00432809.).
// Li Ge 1 , Ming Yang 2 , Na-Na Yang 3 , Xin-Xin Yin 2 and Wen-Gang Song 4 1 Department of Histology and Embryology, School of Basic Medical Sciences, Taishan Medical University, Tai-an City 271000, Shandong Province, PR China 2 Department of Clinical Medicine, Taishan Medical University, Tai-an City 271000, Shandong Province, PR China 3 Key Laboratory of Atherosclerosis in Universities of Shandong, Taishan Medical University, Institute of Atherosclerosis, Taishan Medical University, Tai-an City 271000, Shandong Province, PR China 4 Department of medical immunology, School of Basic Medical Sciences, Taishan Medical University, Tai-an City 271000, Shandong Province, PR China Correspondence to: Wen-Gang Song, email: s.com@163.com Keywords: molecular hydrogen, selective anti-oxidation, gaseous signal modulator, preventive and therapeutic applications Received: April 27, 2017 Accepted: August 26, 2017 Published: September 21, 2017 ABSTRACT Since the 2007 discovery that molecular hydrogen (H 2 ) has selective antioxidant properties, multiple studies have shown that H 2 has beneficial effects in diverse animal models and human disease. This review discusses H 2 biological effects and potential mechanisms of action in various diseases, including metabolic syndrome, organ injury, and cancer; describes effective H 2 delivery approaches; and summarizes recent progress toward H 2 applications in human medicine. We also discuss remaining questions in H 2 therapy, and conclude with an appeal for a greater role for H 2 in the prevention and treatment of human ailments that are currently major global health burdens. This review makes a case for supporting hydrogen medicine in human disease prevention and therapy.
Metal-oxide-semiconductor (MOS) based gas sensors have been considered a promising candidate for gas detection over the past few years. However, the sensing properties of MOS-based gas sensors also need to be further enhanced to satisfy the higher requirements for specific applications, such as medical diagnosis based on human breath, gas detection in harsh environments, etc. In these fields, excellent selectivity, low power consumption, a fast response/recovery rate, low humidity dependence and a low limit of detection concentration should be fulfilled simultaneously, which pose great challenges to the MOS-based gas sensors. Recently, in order to improve the sensing performances of MOS-based gas sensors, more and more researchers have carried out extensive research from theory to practice. For a similar purpose, on the basis of the whole fabrication process of gas sensors, this review gives a presentation of the important role of screening and the recent developments in high throughput screening. Subsequently, together with the sensing mechanism, the factors influencing the sensing properties of MOSs involved in material preparation processes were also discussed in detail. It was concluded that the sensing properties of MOSs not only depend on the morphological structure (particle size, morphology, pore size, etc.), but also rely on the defect structure and heterointerface structure (grain boundaries, heterointerfaces, defect concentrations, etc.). Therefore, the material-sensor integration was also introduced to maintain the structural stability in the sensor fabrication process, ensuring the sensing stability of MOS-based gas sensors. Finally, the perspectives of the MOS-based gas sensors in the aspects of fundamental research and the improvements in the sensing properties are pointed out.
Medical gases are pharmaceutical molecules which offer solutions to a wide array of medical needs. This can range from use in burn and stroke victims to hypoxia therapy in children. More specifically however, gases such as oxygen, helium, xenon, and hydrogen have recently come under increased exploration for their potential theraputic use with various brain disease states including hypoxia-ischemia, cerebral hemorrhages, and traumatic brain injuries. As a result, this article will review the various advances in medical gas research and discuss the potential therapeutic applications and mechanisms with regards to the field of neurobiology.
Natural experimental studies are often recommended as a way of understanding the health impact of policies and other large scale interventions. Although they have certain advantages over planned experiments, and may be the only option when it is impossible to manipulate exposure to the intervention, natural experimental studies are more susceptible to bias. This paper introduces new guidance from the Medical Research Council to help researchers and users, funders and publishers of research evidence make the best use of natural experimental approaches to evaluating population health interventions. The guidance emphasises that natural experiments can provide convincing evidence of impact even when effects are small or take time to appear. However, a good understanding is needed of the process determining exposure to the intervention, and careful choice and combination of methods, testing of assumptions and transparent reporting is vital. More could be learnt from natural experiments in future as experience of promising but lesser used methods accumulates.
BACKGROUND: Methods of classifying chronic obstructive pulmonary disease (COPD) depend largely upon spirometric measurements but disability is only weakly related to measurements of lung function. With the increased use of pulmonary rehabilitation, a need has been identified for a simple and standardised method of categorising disability in COPD. This study examined the validity of the Medical Research Council (MRC) dyspnoea scale for this purpose. METHODS: One hundred patients with COPD were recruited from an outpatient pulmonary rehabilitation programme. Assessments included the MRC dyspnoea scale, spirometric tests, blood gas tensions, a shuttle walking test, and Borg scores for perceived breathlessness before and after exercise. Health status was assessed using the St George's Respiratory Questionnaire (SGRQ) and Chronic Respiratory Questionnaire (CRQ). The Nottingham Extended Activities of Daily Living (EADL) score and Hospital Anxiety and Depression (HAD) score were also measured. RESULTS: Of the patients studied, 32 were classified as having MRC grade 3 dyspnoea, 34 MRC grade 4 dyspnoea, and 34 MRC grade 5 dyspnoea. Patients with MRC grades 1 and 2 dyspnoea were not included in the study. There was a significant association between MRC grade and shuttle distance, SGRQ and CRQ scores, mood state and EADL. Forced expiratory volume in one second (FEV1) was not associated with MRC grade. Multiple logistic regression showed that the determinants of disability appeared to vary with the level of disability. Between MRC grades 3 and 4 the significant covariates were exercise performance, SGRQ and depression score, whilst between grades 4 and 5 exercise performance and age were the major determinants. CONCLUSIONS: The MRC dyspnoea scale is a simple and valid method of categorising patients with COPD in terms of their disability that could be used to complement FEV1 in the classification of COPD severity.
With the emergence of industry 4.0, the oil and gas (O&G) industry is now considering a range of digital technologies to enhance productivity, efficiency, and safety of their operations while minimizing capital and operating costs, health and environment risks, and variability in the O&G project life cycles. The deployment of emerging technologies allows O&G companies to construct digital twins (DT) of their assets. Considering DT adoption, the O&G industry is still at an early stage with implementations limited to isolated and selective applications instead of industry-wide implementation, limiting the benefits from DT implementation. To gain the full potential of DT and related technological adoption, a comprehensive understanding of DT technology, the current status of O&G-related DT research activities, and the opportunities and challenges associated with the deployment of DT in the O&G industry are of paramount importance. In order to develop this understanding, this paper presents a literature review of DT within the context of the O&G industry. The paper follows a systematic approach to select articles for the literature review. First, a keywords-based publication search was performed on the scientific databases such as Elsevier, IEEE Xplore, OnePetro, Scopus, and Springer. The filtered articles were then analyzed using online text analytic software (Voyant Tools) followed by a manual review of the abstract, introduction and conclusion sections to select the most relevant articles for our study. These articles and the industrial publications cited by them were thoroughly reviewed to present a comprehensive overview of DT technology and to identify current research status, opportunities and challenges of DT deployment in the O&G industry. From this literature review, it was found that asset integrity monitoring, project planning, and life cycle management are the key application areas of digital twin in the O&G industry while cyber security, lack of standardization, and uncertainty in scope and focus are the key challenges of DT deployment in the O&G industry. When considering the geographical distribution for the DT related research in the O&G industry, the United States (US) is the leading country, followed by Norway, United Kingdom (UK), Canada, China, Italy, Netherland, Brazil, Germany, and Saudi Arabia. The overall publication rate was less than ten articles (approximately) per year until 2017, and a significant increase occurred in 2018 and 2019. The number of journal publications was noticeably lower than the number of conference publications, and the majority of the publications presented theoretical concepts rather than the industrial implementations. Both these observations suggest that the DT implementation in the O&G industry is still at an early stage.
Featuring high biocompatibility, the emerging field of gas therapy has attracted extensive attention in the medical and scientific communities. Currently, considerable research has focused on the gasotransmitter nitric oxide (NO) owing to its unparalleled dual roles in directly killing cancer cells at high concentrations and cooperatively sensitizing cancer cells to other treatments for synergistic therapy. Of particular note, recent state-of-the-art studies have turned our attention to the chemical design of various endogenous/exogenous stimuli-responsive NO-releasing nanomedicines and their biomedical applications for on-demand NO-sensitized synergistic cancer therapy, which are discussed in this Minireview. Moreover, the potential challenges regarding NO gas therapy are also described, aiming to advance the development of NO nanomedicines as well as usher in new frontiers in this fertile research area.
Biological decontamination using a nonthermal gas discharge at atmospheric pressure in air is the subject of significant research effort at this time. The mechanism for bacterial deactivation undergoes a lot of speculation, particularly with regard to the role of ions and reactive gas species. Two mechanisms have been proposed: electrostatic disruption of cell membranes and lethal oxidation of membrane or cytoplasmic components. Results show that death is accompanied by cell lysis and fragmentation in Gram-negative bacteria but not Gram-positive species, although cytoplasmic leakage is generally observed. Gas discharges can be a source of charged particles, ions, reactive gas species, radicals, and radiation (ultraviolet, infrared, and visible), many of which have documented biocidal properties. The individual roles played by these in decontamination are not well understood or quantified. However, the reactions of some species with biomolecules are documented otherwise in the literature. Oxidative stress is relatively well studied, and it is likely that exposure to gas discharges in air causes extreme oxidative challenge. In this paper, a review is presented of the major reactive species generated by nonthermal plasma at atmospheric pressure and the known reactions of these with biological molecules. Understanding these mechanisms becomes increasingly important as plasma-based decontamination and sterilization devices come closer to a wide-scale application in medical, healthcare, food processing, and air purification applications. Approaches are proposed to elucidate the relative importance of reactive species.
International Journal of Pharmaceutical Sciences and Research (IJPSR) is an official publication of Society of Pharmaceutical Sciences & Research. It is an open access online and print International Journal published monthly. Website: www.ijpsr.com Projected Impact Factor (2012): 2.44, ICV 2012: 5.50, 2011: 5.07, 2010: 4.57 DOI: 10.13040/IJPSR.0975-8232 SJ Impact Factor (2012): 3.226 Global Impact Factor (2013): 0.533, (2012): 0.452 Indexing - EMBASE- Elsevier's
Developing efficient sensor materials with superior performance for selective, fast and sensitive detection of gases and volatile organic compounds (VOCs) is essential for human health and environmental protection, through monitoring indoor and outdoor air pollutions, managing industrial processes, controlling food quality and assisting early diagnosis of diseases. Metal-organic frameworks (MOFs) are a unique type of crystalline and porous solid material constructed from metal nodes (metal ions or clusters) and functional organic ligands. They have been investigated extensively for possible use as high performance sensors for the detection of many different gases and VOCs in recent years, due to their large surface area, tunable pore size, functionalizable sites and intriguing properties, such as electrical conductivity, magnetism, ferroelectricity, luminescence and chromism. The high porosity of MOFs allows them to interact strongly with various analytes, including gases and VOCs, thus resulting in easily measurable responses to different physicochemical parameters. Although much of the recent work on MOF-based luminescent sensors have been summarized in several excellent reviews (up to 2018), a comprehensive overview of these materials for sensing gases and VOCs based on chemiresistive, magnetic, ferroelectric, and colorimertic mechanisms is missing. In this review, we highlight the most recent progress in developing MOF sensing and switching materials with an emphasis on sensing mechanisms based on electricity, magnetism, ferroelectricity and chromism. We provide a comprehensive analysis on the MOF-analyte interactions in these processes, which play a key role in the sensing performance of the MOF-based sensors and switches. We discuss in detail possible applications of MOF-based sensing and switching materials in detecting oxygen, water vapor, toxic industrial gases (such as hydrogen sulfide, ammonia, sulfur dioxide, nitrous oxide, carbon oxides and carbon disulfide) and VOCs (such as aromatic and aliphatic hydrocarbons, ketones, alcohols, aldehydes, chlorinated hydrocarbons and N,N'-dimethylformamide). Overall, this review serves as a timely source of information and provides insight for the future development of advanced MOF materials as next-generation gas and VOC sensors.
For more than two decades, Biotechnology and Bioengineering has documented research focused on natural and engineered microbial biofilms within aquatic and subterranean ecosystems, wastewater and waste-gas treatment systems, marine vessels and structures, and industrial bioprocesses. Compared to suspended culture systems, intentionally engineered biofilms are heterogeneous reaction systems that can increase reactor productivity, system stability, and provide inherent cell:product separation. Unwanted biofilms can create enormous increases in fluid frictional resistances, unacceptable reductions in heat transfer efficiency, product contamination, enhanced material deterioration, and accelerated corrosion. Missing from B&B has been an equivalent research dialogue regarding the basic molecular microbiology, immunology, and biotechnological aspects of medical biofilms. Presented here are the current problems related to medical biofilms; current concepts of biofilm formation, persistence, and interactions with the host immune system; and emerging technologies for controlling medical biofilms.