Search for Periodic Time Variations of the Solar

We report a search for time variations of the solar ^{8}B neutrino flux using 5804 live days of Super-Kamiokande data collected between May 31, 1996, and May 30, 2018. Super-Kamiokande measured the precise time of each solar neutrino interaction over 22 calendar years to search for solar neutrino flux modulations with unprecedented precision. Periodic modulations are searched for in a dataset comprising five-day interval solar neutrino flux measurements with a maximum likelihood method. We also applied the Lomb-Scargle method to this dataset to compare it with previous reports. The only significant modulation found is due to the elliptic orbit of the Earth around the Sun. The observed modulation is consistent with astronomical data: we measured an eccentricity of (1.53±0.35)%, and a perihelion shift of (-1.5±13.5) days.

Comparison of SGLT2 inhibitors vs. DPP4 inhibitors for patients with metabolic dysfunction associated fatty liver disease and diabetes mellitus.

PURPOSE: This study aimed to examine the potential benefit of sodium-glucose cotransporter 2 (SGLT2) inhibitors for patients with metabolic dysfunction-associated fatty liver disease (MAFLD) and diabetes mellitus (DM) using a real-world database. METHODS: We analyzed individuals with MAFLD and DM newly initiated on SGLT2 or dipeptidyl peptidase 4 (DPP4) inhibitors from a large-scale administrative claims database. The primary outcome was the change in the fatty liver index (FLI) assessed using a linear mixed-effects model from the initiation of SGLT2 or DPP4 inhibitors. A propensity score-matching algorithm was used to compare the change in FLI among SGLT2 and DPP4 inhibitors. RESULTS: After propensity score matching, 6547 well-balanced pairs of SGLT2 and 6547 DPP4 inhibitor users were created. SGLT2 inhibitor use was associated with a greater decline in FLI than DPP4 inhibitor use (difference at 1-year measurement, - 3.8 [95% CI - 4.7 to - 3.0]). The advantage of SGLT2 inhibitor use over DPP4 inhibitor use for improvement in FLI was consistent across subgroups. The relationship between SGLT2 inhibitors and amelioration of FLI was comparable between individual SGLT2 inhibitors. CONCLUSIONS: Our analysis using large-scale real-world data demonstrated the potential advantage of SGLT2 inhibitors over DPP4 inhibitors in patients with MAFLD and DM.

Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen.

The KamLAND-Zen experiment has provided stringent constraints on the neutrinoless double-beta (0νßß) decay half-life in ^{136}Xe using a xenon-loaded liquid scintillator. We report an improved search using an upgraded detector with almost double the amount of xenon and an ultralow radioactivity container, corresponding to an exposure of 970 kg yr of ^{136}Xe. These new data provide valuable insight into backgrounds, especially from cosmic muon spallation of xenon, and have required the use of novel background rejection techniques. We obtain a lower limit for the 0νßß decay half-life of T_{1/2}^{0ν}>2.3×10^{26} yr at 90% C.L., corresponding to upper limits on the effective Majorana neutrino mass of 36-156 meV using commonly adopted nuclear matrix element calculations.

Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande.

We report a search for cosmic-ray boosted dark matter with protons using the 0.37 megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1 MeV/c^{2} to 300 MeV/c^{2}.

Erratum: Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande [Phys. Rev. Lett. 130, 031802 (2023)].

This corrects the article DOI: 10.1103/PhysRevLett.130.031802.

Self-Sustained Divertor Oscillation Driven by Magnetic Island Dynamics in Torus Plasma.

A new type of self-sustained divertor oscillation is discovered in the Large Helical Device stellarator, where the peripheral plasma is detached from material diverters by means of externally applied perturbation fields. The divertor oscillation is found to be a self-regulation of an isolated magnetic field structure (the magnetic island) width induced by a drastic change in a poloidal inhomogeneity of the plasma radiation across the detachment-attachment transitions. A predator-prey model between the magnetic island width and a self-generated local plasma current (the bootstrap current) is introduced to describe the divertor oscillation, which successfully reproduces the experimental observations.

Isolation of Rhodococcus equi from the gastrointestinal contents of earthworms (family Megascolecidae).

Rhodococcus equi was isolated from the gastrointestinal contents of earthworms (family Megascolecidae) and their surrounding soil collected from pastures of two horse-breeding farms in Aomori Prefecture, outdoor pig pens, forest in Towada campus, orange groves and forest where wild boars (Sus scrofa) are established in Tanabe, Wakayama Prefecture. The number of R. equi in the lower gastrointestinal contents of 23 earthworms collected from our campus was significantly larger than that of the upper gastrointestinal content. The mean numbers of R. equi from the gastrointestinal contents of earthworms collected from the various places were 2·3-fold to 39·7-fold more than those of the surrounding soil samples. In all, 1771 isolates from the earthworms and 489 isolates from the soil samples were tested for the presence of vapA and vapB genes using polymerase chain reaction. At the horse-breeding farm N, 9 of the 109 isolates (8·3%) from the earthworms and 7 of the 106 isolates (6·6%) from the soil samples were positive for the vapA gene. At the University's forest, one of the 250 isolates (0·4%) from the gastrointestinal contents of the earthworm was positive for the vapB gene. These results revealed that R. equi can be found in significant quantities in the gastrointestinal contents of earthworms, suggesting that they act as an accumulator of R. equi in the soil environment and as a source or reservoir of animal infection.

Virulence plasmids in clinical isolates of Rhodococcus equi from sick foals in the Netherlands.

Clinical samples from 123 foals with suspected rhodococcosis submitted to the Veterinary Microbiological Diagnostic Centre of the Faculty of Veterinary Medicine between 1993 and 2006 were tested for the presence of the virulence gene vapA. Of the 123 samples, 120 were vapA-positive and 3 vapA-negative Rhodococcus equi were isolated. The 120 vapA-positive R. equi were isolated from 70 tracheal wash, 19 lung tissues, 7 lymph nodes, 6 synovial fluids, 13 abscesses or pus and single isolates from the uterus, gut, cerebrospinal fluid, abdomen fluid and faeces. Of the 120 isolates, 46 were from Dutch warmblood horses, 23 from Friesian horses, 14 from Trotters, 4 from Holsteiners, 3 from Arab breed, 2 from ponies, 1 from a Welsh pony and 27 from undefined breed horses. Using plasmid profile analysis of the 120 isolates, 117 isolates contained the 85-kb type I plasmid, 2 contained the 87-kb type I plasmid and 1 contained the novel 52-kb non-mobilizable virulence plasmid reported recently. These results showed that the virulent R. equi strains harbouring a virulence plasmid of 85-kb type I or 87-kb type I, which have been detected in clinical isolates from five European countries, are widespread in the Netherlands. This is the first report of plasmid types of clinical R. equi isolates in the Netherlands.

One-Year In Situ Incubation of Pyrite at the Deep Seafloor and Its Microbiological and Biogeochemical Characterizations.

In this study, we performed a year-long in situ incubation experiment on a common ferrous sulfide (Fe-S) mineral, pyrite, at the oxidative deep seafloor in the hydrothermal vent field in the Izu-Bonin arc, Japan, and characterized its microbiological and biogeochemical properties to understand the microbial alteration processes of the pyrite, focusing on Fe(II) oxidation. The microbial community analysis of the incubated pyrite showed that the domain Bacteria heavily dominated over Archaea compared with that of the ambient seawater, and Alphaproteobacteria and Gammaproteobacteria distinctively codominated at the class level. The mineralogical characterization by surface-sensitive Fe X-ray absorption near-edge structure (XANES) analysis revealed that specific Fe(III) hydroxides (schwertmannite and ferrihydrite) were locally formed at the pyrite surface as the pyrite alteration products. Based on the Fe(III) hydroxide species and proportion, we thermodynamically calculated the pH value at the pyrite surface to be pH 4.9 to 5.7, indicating that the acidic condition derived from pyrite alteration was locally formed at the surface against neutral ambient seawater. This acidic microenvironment at the pyrite surface might explain the distinct microbial communities found in our pyrite samples. Also, the acidity at the pyrite surface indicates that the abiotic Fe(II) oxidation rate was much limited at the pyrite surface kinetically, 3.9 × 103- to 1.6 × 105-fold lower than that in the ambient seawater. Moreover, nanoscale characterization of microbial biomolecules using carbon near-edge X-ray absorption fine-structure (NEXAFS) analysis showed that the sessile cells attached to pyrite excreted the acidic polysaccharide-rich extracellular polymeric substances at the pyrite surface, which can lead to the promotion of biogenic Fe(II) oxidation and pyrite alteration. IMPORTANCE Pyrite is one of the most common Fe-S minerals found in submarine hydrothermal environments. Previous studies demonstrated that the Fe-S mineral can be a suitable host for Fe(II)-oxidizing microbes in hydrothermal environments; however, the details of microbial Fe(II) oxidation processes with Fe-S mineral alteration are not well known. The spectroscopic and thermodynamic examination in the present study suggests that a moderately acidic pH condition was locally formed at the pyrite surface during pyrite alteration at the seafloor due to proton releases with Fe(II) and sulfidic S oxidations. Following previous studies, the abiotic Fe(II) oxidation rate significantly decreases with a decrease in pH, but the biotic (microbial) Fe(II) oxidation rate is not sensitive to the pH decrease. Thus, our findings clearly suggest that the pyrite surface is a unique microenvironment where abiotic Fe(II) oxidation is limited and biotic Fe(II) oxidation is more prominent than that in neutral ambient seawater.

Cumulative incidence of femoral localized periosteal thickening (beaking) preceding atypical femoral fractures in patients with rheumatoid arthritis.

The incidence of localized periosteal thickening (LPT, also termed beaking) of the lateral cortex that often precedes an atypical femoral fracture (AFF) was not high in patients with rheumatoid arthritis (RA) but incomplete AFFs developed in two patients. Higher-dose prednisolone was a significant risk factor for LPT in patients with RA. INTRODUCTION: Atypical femoral fractures (AFFs) are stress fractures; bisphosphonate (BP) use is a major risk factor for the development of such fractures. Localized periosteal thickening (LPT, also termed beaking) of the lateral cortex often precedes a complete or incomplete AFF. We evaluated the incidence of latent LPT in patients with rheumatoid arthritis (RA), to evaluate LPT progression, and to define LPT risk factors. METHODS: A total of 254 patients with RA were included; all underwent annual X-ray evaluation, dual-energy X-ray absorptiometry, and analyses of serum and bone metabolic markers for 2-3 years. LPT of the lateral cortex was sought in femoral X-rays. RESULTS: The incidence of LPT was 2.4% (6/254). Among patients on both BP and prednisolone (PSL) at enrollment, the incidence was 2.3% (3/131). Two femurs of two patients with LPT developed incomplete AFFs; LPT was extensive and associated with endosteal thickening. One patient had been on BP and PSL and microscopic polyangiitis was comorbidity. The other was on a selective estrogen receptor modulator and PSL. A daily PSL dose >5 mg (OR 11.4; 95%CI 2.15-60.2; p = 0.004) and higher-dose methotrexate (OR 1.22; 95%CI 1.01-1.49; p = 0.043) were significant risk factors for LPT. CONCLUSIONS: The incidence of latent LPT was not high (2.4%) but incomplete AFFs developed in two RA patients. Higher-dose PSL because of a comorbid disease requiring glucocorticoid treatment other than RA or refractory RA were risk factors for LPT; X-ray screening for latent LPT would usefully prevent complete AFFs.

Impact of Magnetic Field Configuration on Heat Transport in Stellarators and Heliotrons.

We assess the magnetic field configuration in modern fusion devices by comparing experiments with the same heating power, between a stellarator and a heliotron. The key role of turbulence is evident in the optimized stellarator, while neoclassical processes largely determine the transport in the heliotron device. Gyrokinetic simulations elucidate the underlying mechanisms promoting stronger ion scale turbulence in the stellarator. Similar plasma performances in these experiments suggests that neoclassical and turbulent transport should both be optimized in next step reactor designs.

Effects of oral administration of timothy hay and psyllium on the growth performance and fecal microbiota of preweaning calves.

The objective of this study was to evaluate the effects of oral administration of fiber from the first week of life on the growth and hindgut environment of preweaning calves. Twenty newborn female Holstein calves were divided into 2 groups as control and treatment. Calves in both groups were reared under the same feeding program except for oral fiber administration. Timothy hay and psyllium were mixed at a 50-to-6 ratio as a treatment diet for oral fiber administration. Calves in the treatment group were orally administered 50 g of fiber daily from 3 to 7 d of age and 100 g of fiber from 8 d of age until weaning. Feed intake and occurrence of diarrhea were recorded daily, and body weight (BW) was recorded weekly for the individual calf. Fresh feces were collected from calves at 7, 21, 35, 49, and 56 d of age to analyze fermentation parameters and microbiota to characterize the hindgut environment. Higher fiber intake in the treatment group due to oral administration of timothy and psyllium did not affect the starter intake and achieved higher BW at 21 d of age. The fecal pH, total volatile fatty acid, lactate, and ammonia nitrogen concentrations were not affected by oral fiber administration; meanwhile, the molar proportion of propionate was higher in the treatment group at 7 d of age. The difference in fecal microbiota in the calves subjected to the oral administration of fiber was observed within 21 d of life; Lactobacillus spp. and Prevotella spp. showed higher abundance, whereas that of Clostridium perfringens was decreased. These higher abundances of beneficial bacteria and lower abundance of pathogenic bacteria during early life may partly explain the higher BW of calves in the treatment group at 21 d of age. Furthermore, no adverse effect was observed for the BW and health status in the treatment group throughout the preweaning period. Therefore, early fiber feeding via oral administration potentially contributes to improving the hindgut environment in newborn calves, which leads to better growth of calves during the early stage of life.

Cranial nerve involvement in typical and atypical chronic inflammatory demyelinating polyneuropathies.

BACKGROUND AND PURPOSE: Cranial nerve palsy is occasionally present in patients with chronic inflammatory demyelinating polyneuropathy (CIDP), but its prevalence, characteristics and relations with the CIDP subtypes have rarely been investigated. The aim of this study was to systematically assess cranial nerve involvement in typical and atypical CIDP. METHODS: Clinical data were reviewed in 132 consecutive patients with CIDP, including typical CIDP (n = 89), multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) (n = 31), distal acquired demyelinating symmetric (DADS) (n = 9) and others (n = 3). RESULTS: The frequency of cranial nerve palsy was 11% in typical CIDP, 48% in MADSAM and 11% in DADS. Facial and bulbar palsy was most frequently present (9%), followed by ocular motor nerve palsy (5%). Bilateral involvement was seen in all typical CIDP and DADS patients, whereas 80% of MADSAM patients had unilateral palsy. The presence of cranial nerve involvement was associated with more severe limb muscle weakness in typical CIDP, but not in MADSAM. Cranial nerve palsy fully recovered in 90% of typical CIDP and in 67% of MADSAM patients. CONCLUSION: Amongst the CIDP subtypes, cranial palsy is frequent and unilateral in MADSAM, and less frequent and bilateral in typical CIDP and DADS. In typical CIDP, facial and bulbar palsy reflects more severe and extensive inflammation.

Reinvestigation of the virulence of Rhodococcus equi isolates from patients with and without AIDS.

Rhodococcus equi emerged as a zoonotic pathogen of human immunodeficiency virus-infected patients over the last three decades. Two virulence plasmid types of R. equi, pVAPA and pVAPB associated with equine and porcine isolates, have been recognized, and more recently, pVAPN, a novel host-associated virulence plasmid in R. equi, was found in bovine and caprine isolates. We reinvestigated 39 previously reported isolates of R. equi from patients with and without acquired immunodeficiency syndrome (AIDS) by detecting vapA, vapB and vapN using PCR and plasmid profiling. After excluding one isolate that could not be cultured from frozen storage, eight isolates carried a virulence plasmid encoding vapA (pVAPA), 10 carried a virulence plasmid encoding vapB (pVAPB), seven carried a virulence plasmid encoding vapN (pVAPN) and 13 were negative for those genes. Of the 29 isolates from patients with AIDS, 7, 10 and 5 harboured pVAPA, pVAPB and pVAPN respectively. Among nine isolates from patients without AIDS, one and two harboured pVAPA and pVAPN respectively. This study demonstrated that pVAPN-positive R. equi existed in human isolates before 1994 and reaffirmed that equine-associated pVAPA-positive, porcine-associated pVAPB-positive and bovine- or caprine-associated pVAPN-positive R. equi are widely spread globally. Because domestic animals might be major sources of human infection, further research is needed to reveal the prevalence of pVAPN-positive R. equi infection in cattle and goats.

Effect of Gum Chewing on PFC Activity During Discomfort Sound Stimulation.

The prefrontal cortex (PFC) is sensitive to the stress exposure and involved in stress coping. And the effects of gum chewing on the stress have been studied using NIRS. However, when measuring NIRS on PFC during gum chewing, blood flows in shallow tissues (scalp, skin, muscle) might be affected. A NIRS used in the present study first, which has a short distance (1 cm) and the usual (3 cm) source-detector (S-D) regression, can allow eliminating shallow tissues effect of gum chewing. The aim of this study was to investigate the hypothesis that gum chewing activates the right prefrontal cortex (PFC) in stress coping against negative sounds (NS) from the International Affective Digitized Sounds-2 (IADS) as a mental stress task. NS showed activation in the right PFC. There was a significant difference between NS, and NS with Gum, where NS with Gum showed an increased PFC activity, increased alpha wave appearance rate, a higher value in heart rate level, and a higher VAS score indicating 'pleasant'. Gum chewing activated right PFC activity while exposed to negative sounds from IADS as a mental stress task.

New physician specialty training system impact on distribution of trainees in Japan.

OBJECTIVES: The problem of uneven distribution of medical services and inequitable distribution of physicians is drawing much attention worldwide. Revealing how changes in the specialty training system in Japan have affected the distribution of doctors could help us understand this problem. In 2018, a new and standardized specialty training system was implemented by the Japanese Medical Specialty Board, which is recognized by the Ministry of Health, Labor and Welfare. The purpose of this study was to investigate how this new system has affected the geographical distribution of doctors commencing specialty training (trainees) and choice of specialty in Japan. STUDY DESIGN: Retrospective observational study. METHODS: The change in the number of trainees between the control period (2012-2014) and 2018 was investigated, taking into account the prefecture and specialty selected. Population, the proportion of residents aged 65 years or older (aging rate), and the total number of overall doctors in each prefecture were considered as the background characteristics of each prefecture. We created a Lorenz curve and calculated the Gini coefficient for the distribution of trainees. RESULTS: In 2018, the number of trainees per 100,000 population increased to 6.6 nationwide compared with 5.5 during the control period. The number of trainees per 100,000 population in 2018 increased in prefectures with a large population of ≧ 2,000,000, a low aging rate (<27%), and a high doctor density (≧ 250 doctors per 100,000 population). The Gini coefficient showed an increase to 0.226 in 2018 compared with only 0.160 during the control period. CONCLUSIONS: After the implementation of the new training system, there was an increase in the number of doctors enrolling in specialty programs, and the specialties other than internal medicine and surgery have attracted more trainees. Inequality in the distribution of doctors between urban and rural prefectures worsened. This indicates the need to explore new ways of balancing distribution while maintaining optimal opportunities for specialist training.

Negative motor networks: Electric cortical stimulation and diffusion tensor imaging.

INTRODUCTION: This study investigated the networks of Negative motor areas (NMAs) using electric cortical stimulation and diffusion tensor imaging (DTI). METHODS: Twelve patients with intractable focal epilepsy, in which NMAs were identified by electrical cortical stimulation, were enrolled in this study. Electric stimulation at 50Hz was applied to the electrodes during motor tasks to identify the NMAs. DTI was used to identify the subcortical fibers originating from the NMAs found by electrical stimulation. RESULTS: NMAs were found in lateral frontal areas (premotor area (PM) and precentral gyrus) in all 12 patients, in pre-supplementary motor areas (pre-SMAs) in four patients, and in posterior parietal cortices (PPCs) in four. DTI detected fibers connecting to the ipsilateral PMs, PPCs and temporal regions via U-fibers, superior longitudinal fasciculus (SLF), and arcuate fasciculus (AF) from the lateral frontal NMAs. Pre-SMA-NMAs had connections with ipsilateral PMs and contralateral pre-SMAs via the frontal aslant tract and transcallosal commissural fibers, and PPC-NMAs with ipsilateral PMs via SLF and AF. CONCLUSION: This study found the characteristic cortical network of each NMA, and especially revealed new insight of pre-SMA-NMA and PPC NMA. These NMAs might be associated with different mechanism of negative motor response.

Dynamics of immunocyte activation during intravenous immunoglobulin treatment in Kawasaki disease.

Objectives: Kawasaki disease (KD) is a systemic vasculitis of early childhood. Intravenous immunoglobulin (IVIG) is the standard treatment for KD. However, IVIG is not effective in approximately 15% of children with KD, and the mechanisms for this are unclear. We investigated changes in monocyte and T-cell activation from pre- to post-IVIG in IVIG-effective and IVIG-resistant KD.Method: We analysed peripheral CD14+CD16+ cells and human leucocyte antigen-DR (HLA-DR) expression on CD4+ and CD8+ cells in 46 children with KD who were admitted to Yamaguchi University Hospital between January 2011 and May 2016. We compared the kinetics in the absolute numbers of CD14+CD16+ cells, CD4+HLA-DR+ cells, and CD8+HLA-DR+ cells before and after IVIG treatment between IVIG-effective and IVIG-resistant groups.Results: Among the 46 subjects, 30 had IVIG-effective KD and 16 had IVIG-resistant KD. The absolute number of CD14+CD16+ cells in the IVIG-effective group decreased significantly after IVIG, while that in the IVIG-resistant group showed no change after IVIG. The absolute number of CD4+HLA-DR+ cells increased significantly after IVIG in both groups. The absolute number of CD8+HLA-DR+ cells before IVIG was low and significantly increased after IVIG in the IVIG-resistant group, while that in the IVIG-effective group showed no change after IVIG.Conclusions: Our results suggest that insufficient control of monocyte suppression and T-cell activation, especially in terms of the CD8-related immune system, are associated with IVIG resistance. The restoration of T-cell suppression may be important for KD recovery. These findings provide insight into the mechanism of IVIG resistance.

Radiofrequency identification tag system improves the efficiency of closed vitrification for cryopreservation and thawing of bovine ovarian tissues.

PURPOSE: A radiofrequency identification (RFID) tag system was designed to streamline cryopreservation and thawing procedures. This study evaluated the usefulness of the RFID tag system for improving the efficiency of cryopreserving/thawing bovine ovarian tissue by the closed vitrification protocol. METHODS: Six participants carried out closed vitrification and thawing of bovine ovarian tissues procedures using either the conventional or the new RFID tag method, and the time required to perform each step of the respective methods was measured. After normality of data was confirmed by the Shapiro-Wilk test, the significance of differences was assessed by the unpaired t test. RESULTS: When closed vitrification was performed, the time required for each step showed a significant difference between the two methods (t(4) = 2.938, p = 0.042, d = 2.40), and the total cryopreservation time was 11 min shorter using the RFID tag system. When thawing was performed, the time required for each step also showed a significant difference between the two methods (t(4) = 2.797, p = 0.049, d = 2.28), and the total thawing time was 2 min shorter using the RFID tag system. CONCLUSION: The RFID tag system tested in this study seems to be suitable for managing biological samples stored in liquid nitrogen. Adoption of an RFID tag system by fertility centers may not only improve the efficiency of cryopreserving/thawing reproductive tissues but could also reduce human error.

Sputum-to-serum hydrogen sulphide ratio as a novel biomarker of predicting future risks of asthma exacerbation.

BACKGROUND: Increased level of hydrogen sulphide (H2 S) in sputum is reported to be a new biomarker of neutrophilic airway inflammation in chronic airway disorders. However, the relationship between H2 S and disease activity remains unclear. OBJECTIVE: We investigated whether H2 S levels could vary during different conditions in asthma. METHOD: H2 S levels in sputum and serum were measured using a sulphide-sensitive electrode in 47 stable asthmatic subjects (S-BA), 21 uncontrolled asthmatic subjects (UC-BA), 26 asthmatic subjects with acute exacerbation (AE-BA) and 15 healthy subjects. Of these, H2 S levels during stable, as well as exacerbation states, were obtained in 13 asthmatic subjects. RESULTS: Sputum H2 S levels were significantly higher in the AE-BA subjects compared to the UC-BA and healthy subjects (P < .05). However, serum H2 S levels in the AE-BA subjects were lower than in the S-BA subjects (P < .001) and similar to those in healthy subjects. Thus, the sputum-to-serum ratio of H2 S (H2 S ratio) in the AE-BA subjects was significantly higher than in the S-BA, UC-BA and healthy subjects (P < .05). Among all subjects, sputum H2 S levels showed a trend to decrease with FEV1 %predicted and significantly positive correlations with sputum neutrophils (%), sputum IL-8 and serum IL-8. A multiple linear regression analysis showed that sputum H2 S was independently associated with increased sputum neutrophils (%) and decreased FEV1 %predicted (P < .05). The cut-off level of H2 S ratio to indicate an exacerbation was ≥0.34 (area under the curve; 0.88, with a sensitivity of 81.8% and specificity of 72.7%, P < .001). Furthermore, half of the asthmatic subjects with H2 S ratios higher than the cut-off level experienced asthma exacerbations over the following 3 months after enrolment. CONCLUSIONS: The H2 S ratio may provide useful information on predicting future risks of asthma exacerbation, as well as on obstructive neutrophilic airway inflammation as one of the non-Th2 biomarkers, in asthma.