Vertical stratification of the air microbiome in the lower troposphere.

The troposphere constitutes the final frontier of global ecosystem research due to technical challenges arising from its size, low biomass, and gaseous state. Using a vertical testing array comprising a meteorological tower and a research aircraft, we conducted synchronized measurements of meteorological parameters and airborne biomass (n = 480) in the vertical air column up to 3,500 m. The taxonomic analysis of metagenomic data revealed differing patterns of airborne microbial community composition with respect to time of day and height above ground. The temporal and spatial resolution of our study demonstrated that the diel cycle of airborne microorganisms is a ground-based phenomenon that is entirely absent at heights >1,000 m. In an integrated analysis combining meteorological and biological data, we demonstrate that atmospheric turbulence, identified by potential temperature and high-frequency three-component wind measurements, is the key driver of bioaerosol dynamics in the lower troposphere. Multivariate regression analysis shows that at least 50% of identified airborne microbial taxa (n = ∼10,000) are associated with either ground or height, allowing for an understanding of dispersal patterns of microbial taxa in the vertical air column. Due to the interconnectedness of atmospheric turbulence and temperature, the dynamics of microbial dispersal are likely to be impacted by rising global temperatures, thereby also affecting ecosystems on the planetary surface.

Microbial communities in the tropical air ecosystem follow a precise diel cycle.

The atmosphere is vastly underexplored as a habitable ecosystem for microbial organisms. In this study, we investigated 795 time-resolved metagenomes from tropical air, generating 2.27 terabases of data. Despite only 9 to 17% of the generated sequence data currently being assignable to taxa, the air harbored a microbial diversity that rivals the complexity of other planetary ecosystems. The airborne microbial organisms followed a clear diel cycle, possibly driven by environmental factors. Interday taxonomic diversity exceeded day-to-day and month-to-month variation. Environmental time series revealed the existence of a large core of microbial taxa that remained invariable over 13 mo, thereby underlining the long-term robustness of the airborne community structure. Unlike terrestrial or aquatic environments, where prokaryotes are prevalent, the tropical airborne biomass was dominated by DNA from eukaryotic phyla. Specific fungal and bacterial species were strongly correlated with temperature, humidity, and CO2 concentration, making them suitable biomarkers for studying the bioaerosol dynamics of the atmosphere.

Ultra-low NA step-index large mode area Yb-doped fiber with a germanium doped cladding for high power pulse amplification.

High concentration rare earth doped, large mode area (LMA) step-index fibers, which feature a very high cladding absorption per unit length at the pump wavelength, high efficiency, and excellent beam quality, are ideal for high power pulsed fiber lasers/amplifiers where large effective mode areas and short device lengths are crucial in order to reduce detrimental nonlinear effects associated with high peak power operation. In this Letter, we realize low numerical aperture (NA) high absorption fibers, simply by employing a germanium (Ge)-doped cladding rather than a pure silica cladding to offset the high refractive index associated with using a high concentration of ytterbium (Yb) in the core. This approach allows us to separate the two inter-linked fiber design parameters of pump absorption and NA in a step-index fiber. Using a conventional modified chemical vapor deposition process combined with solution doping, a low NA (0.04), LMA (475µm2) silica fiber is fabricated with a cladding absorption value of >20dB/m, which is the highest value among LMA step-index fibers with NA<0.06 so far reported to the best of our knowledge. The fabricated Yb-doped fiber was tested in a high-power picosecond amplifier system and enabled the generation of 190 ps laser pulses with a 101 µJ pulse energy and 0.5 MW peak power at an average power of 150 W.

Whole-Genome Sequencing of Aspergillus terreus Species Complex.

Aspergillus terreus species complex is an opportunistic fungal pathogen increasingly implicated in invasive infection, as well as chronic respiratory disease. Currently, an understanding of A. terreus pathogenicity is impeded by a limited number of whole-genome sequences of this fungal pathogen. We here describe a high-quality whole-genome assembly of European A. terreus clinical isolate M6925, derived by single-molecule real-time sequencing with short-read polishing.

Randomised controlled trial of dexmedetomidine sedation vs general anaesthesia for inguinal hernia surgery on perioperative outcomes in infants.

BACKGROUND: Neonates and infants undergoing general anaesthesia for hernia surgery are at risk of perioperative cardiorespiratory adverse events. The use of regional anaesthesia with dexmedetomidine preserves airway tone and may potentially avoid these complications. This study compares the perioperative conditions and adverse events between dexmedetomidine sedation with caudal block and general anaesthesia with caudal block for inguinal hernia surgery in infants. METHODS: A randomised controlled trial was conducted in a tertiary hospital in Singapore involving 104 infants younger than 3 months, who were randomised to receive either dexmedetomidine sedation (DEX) with caudal block or general sevoflurane anaesthesia with tracheal intubation and caudal block (GA) for inguinal hernia surgery. Perioperative conditions, haemodynamics and adverse events were compared between groups. RESULTS: Fifty-one infants received DEX and 48 infants received GA. In the DEX group, 46 infants (90.2%) had their operations completed solely under this technique, two (3.9%) were converted to general anaesthesia with intubation, and three (5.9%) required brief administration of nitrous oxide or low-dose sevoflurane. Overall, 96.1% of infants in the DEX group did not require intubation. Perioperative conditions were similar in both groups. The DEX group had significantly lower heart rates and higher mean arterial pressures intraoperatively. Two infants in the DEX group (3.9%) required postoperative intensive care admission compared with six infants (12.5%) in the GA group. CONCLUSIONS: Dexmedetomidine sedation with caudal block provides a feasible alternative to general anaesthesia in infants undergoing hernia surgery. This technique avoids the need for tracheal intubation, which may be beneficial in neonates. CLINICAL TRIAL REGISTRATION: NCT02559102.

Step-index high-absorption Yb-doped large-mode-area fiber with Ge-doped raised cladding.

We report an all-solid large-mode-area (LMA) step-index fiber offering high absorption and low core numerical aperture (NA) by introducing a highly ytterbium-doped P:Al core and germanium-doped cladding. The fiber provides core absorption of ∼1200 dB/m at 976 nm with a low 0.07 core NA, due to the raised Ge cladding. Furthermore, matched profiles of P and Al across the core are successfully obtained with high concentration of Yb2O3 around 0.4 mol%. The fiber characteristics are routinely achievable by conventional modified chemical vapor deposition with a solution doping technique. A highly efficient laser with >100 W output power, 86% slope efficiency with respect to launched pump power, and a mean M2 of 1.34 has been demonstrated using the fabricated LMA step-index fiber. We also report 80% laser slope efficiency with 58 W output power (pump power limited) within only 0.5 m of the fiber when pumped by a wavelength-stabilized laser diode.

Validation of the Patient Activation Measure (PAM-13) among adults with cardiac conditions in Singapore.

PURPOSE: The Patient Activation Measure (PAM-13) measures patients' knowledge, skill, and confidence in chronic condition self-management. The purpose of this study was to assess the validity of PAM-13 (English version) among English-speaking adults with cardiac conditions in Singapore. METHODS: A cross-sectional study was conducted in a convenient sample of 270 heart clinic patients. Using the unitary concept of validity, evidence of (1) internal structure via data quality, unidimensionality, differential item functioning, and internal consistency, (2) response process through item difficulty and item fit using Rasch modeling, and (3) relationship to other variables via correlations with depression and self-efficacy were examined. RESULTS: The item response was high with only one missing answer. All items had a small floor effect, but nine out of 13 items had a ceiling effect larger than 15 %. Cronbach's α was 0.86, and average inter-item correlations was 0.324. Results suggested unidimensionality; however, differences in item difficulty ranking were found. A low, negative correlation was found with depression, while a moderate, positive correlation was found with self-efficacy. CONCLUSION: Evidence in all three areas of validity were mixed. Caution should be exercised when using categorical activation "level" to inform clinical decisions.

Experimental parameters defining ultra-low biomass bioaerosol analysis.

Investigation of the microbial ecology of terrestrial, aquatic and atmospheric ecosystems requires specific sampling and analytical technologies, owing to vastly different biomass densities typically encountered. In particular, the ultra-low biomass nature of air presents an inherent analytical challenge that is confounded by temporal fluctuations in community structure. Our ultra-low biomass pipeline advances the field of bioaerosol research by significantly reducing sampling times from days/weeks/months to minutes/hours, while maintaining the ability to perform species-level identification through direct metagenomic sequencing. The study further addresses all experimental factors contributing to analysis outcome, such as amassment, storage and extraction, as well as factors that impact on nucleic acid analysis. Quantity and quality of nucleic acid extracts from each optimisation step are evaluated using fluorometry, qPCR and sequencing. Both metagenomics and marker gene amplification-based (16S and ITS) sequencing are assessed with regard to their taxonomic resolution and inter-comparability. The pipeline is robust across a wide range of climatic settings, ranging from arctic to desert to tropical environments. Ultimately, the pipeline can be adapted to environmental settings, such as dust and surfaces, which also require ultra-low biomass analytics.

IGLR-2, a Leucine-Rich Repeat Domain Containing Protein, Is Required for the Host Defense in Caenorhabditis elegans.

Enterohemorrhagic Escherichia coli (EHEC), a human pathogen, also infects Caenorhabditis elegans. We demonstrated previously that C. elegans activates the p38 MAPK innate immune pathway to defend against EHEC infection. However, whether a C. elegans pattern recognition receptor (PRR) exists to regulate the immune pathway remains unknown. PRRs identified in other metazoans contain several conserved domains, including the leucine-rich repeat (LRR). By screening a focused RNAi library, we identified the IGLR-2, a transmembrane protein containing the LRR domain, as a potential immune regulator in C. elegans. Our data showed that iglr-2 regulates the host susceptibility to EHEC infection. Moreover, iglr-2 is required for pathogen avoidance to EHEC. The iglr-2 overexpressed strain, which was more resistant to EHEC originally, showed hypersusceptibility to EHEC upon knockdown of the p38 MAPK pathway. Together, our data suggested that iglr-2 plays an important role in C. elegans to defend EHEC by regulating pathogen-avoidance behavior and the p38 MAPK pathway.

Taxonomic composition and seasonal dynamics of the air microbiome in West Siberia.

Here, we describe taxonomical composition, as well as seasonal and diel dynamics of airborne microbial communities in West Siberia. A total of 78 airborne biomass samples from 39 time intervals were analysed, within a temperature range of 48 °C (26 °C to - 22 °C). We observed a 5-170-fold decrease in DNA yield extracted from the airborne biomass in winter compared to summer, nevertheless, yielding sufficient material for metagenomic analysis. The airborne microbial communities included Actinobacteria and Proteobacteria, Ascomycota and Basidiomycota fungi as major components, as well as some Streptophyta plants. In summer, bacterial and fungal plant pathogens, and wood-rotting saprophytes were predominant. In winter, Ascomycota moulds and cold-related or stress environment bacterial species were enriched, while the fraction of wood-rotting and mushroom-forming Basidiomycota fungi was largely reduced. As recently reported for the tropical climate, the airborne microbial communities performed a diel cycle in summer, however, in winter diel dynamics were not observed.

Skin-to-epidural distance in the Southeast Asian paediatric population: multiethnic morphometrics and international comparisons.

INTRODUCTION: Paediatric epidurals can present technical challenges due to wide variations in age and weight among children, ranging from neonates to teenagers. This study evaluated the skin-to-epidural distance in the thoracic and lumbar regions to determine the relationship between age, weight and ethnicity and depth to the epidural space in our Singapore paediatric population. METHODS: Data from the Acute Pain Service was prospectively collected over 16 years. Details included patient demographics, level of epidural performed and distance from skin to epidural space. Multivariable regression analysis was performed to determine the association of weight, age, ethnicity and gender with the depths to the thoracic and lumbar epidural spaces. A simple linear regression was calculated to predict the depth to both thoracic and lumbar epidural spaces based on body weight. Equations were formulated to describe the relationship between weight and depth of epidural space. RESULTS: A total of 616 midline epidurals were studied. Regression analysis was performed for 225 thoracic epidurals and 363 lumbar epidurals. Our study revealed a clear correlation between skin-to-lumbar epidural distance and weight in children. The best correlation was demonstrated between skin-to-lumbar epidural distance and body weight (R2 = 0.729). This relationship was described by the formula: depth (mm) = (0.63 × weight [kg]) + 9.2. CONCLUSION: Skin-to-lumbar epidural distance correlated with weight in children. Our results highlighted the clinical significance of differences between Southeast Asian paediatric populations when compared to other populations.

Sleeve Gastrectomy and Roux-En-Y Gastric Bypass Lead to Comparable Changes in Body Composition in a Multiethnic Asian Population.

BACKGROUND: Changes in body composition after bariatric surgery such as a sustained loss of body fat are often associated with an inevitable loss of fat free mass. This can contribute to an undesirable disturbance in resting metabolic rate and weight maintenance. Our aim was to study changes in body composition in a multiethnic Asian cohort following bariatric surgery and to identify differences between laparoscopic sleeve gastrectomy and laparoscopic Roux-en-Y gastric bypass. METHODS: A retrospective review of prospectively collected data on 295 patients who underwent either laparoscopic sleeve gastrectomy (256 patients) or laparoscopic Roux-en-Y gastric bypass (39 patients) was performed. Body composition variables were measured with the analyzer, GAIA 359 PLUS, which included the parameters; total body weight, body mass index, excess weight, basal metabolic rate, fat-free mass, fat mass, and total body water. RESULTS: There were no statistical differences in gender, ethnicity, age, weight, height, and body mass index between laparoscopic sleeve gastrectomy and Roux-en-Y gastric bypass. At each time point (6, 12, 24, and 36 months) post-operation, there was no significant differences in % total body weight loss, basal metabolic rate, fat mass, fat percentage, and total body water between sleeve gastrectomy and bypass patients. There was significant difference (p < 0.05) in fat free mass only at 3 years post-operation, with sleeve gastrectomy patients having 9.79 kg less fat-free mass than bypass patients. However, after multivariate analysis, we found no statistically significant differences. CONCLUSION: Sleeve gastrectomy and gastric bypass seemed to give similar changes to body composition.

Complete Genome Sequence of Curtobacterium sp. Strain SGAir0471, Isolated from Singapore Air Samples.

Curtobacterium sp. strain SGAir0471 was isolated from tropical air samples collected in Singapore. The genome was assembled using PacBio RS II long reads and Illumina MiSeq short paired-end reads. The complete genome measures 3.53 Mb and consists of 3,151 protein-coding genes, 49 tRNAs, and 12 rRNAs.

Genome Sequence of the Tropical Atmosphere Bacterium Pontibacter sp. Strain SGAir0037.

The Pontibacter bacterial genus has been detected in marine and soil environments. Here, we report the genome sequence of Pontibacter sp. strain SGAir0037, which was isolated from outdoor air samples collected in Singapore. The genome comprises one chromosome of 5.26 Mb and one plasmid of 127 kb.

Complete Genome Sequence of Nissabacter sp. Strain SGAir0207, Isolated from an Air Sample Collected in Singapore.

Nissabacter sp. strain SGAir0207 was isolated from a tropical air sample collected in Singapore. Its genome was assembled using a hybrid approach with long and short reads, resulting in one chromosome of 3.9 Mb and 7 plasmids. The complete genome consists of 4,403 protein-coding, 84 tRNA, and 22 rRNA genes.

Complete Genome Sequence of Brachybacterium sp. Strain SGAir0954, Isolated from Singapore Air.

Brachybacterium sp. strain SGAir0954 was isolated from tropical air collected in Singapore, and its genome was sequenced and assembled using long reads generated by single-molecule real-time (SMRT) sequencing. The complete genome has a size of 3.41 Mb and consists of 2,955 protein coding genes, 50 tRNAs, and 9 rRNAs.

How adults with cardiac conditions in Singapore understand the Patient Activation Measure (PAM-13) items: a cognitive interviewing study.

PURPOSE: Validation studies of the PAM-13 have found differences in scale performance, suggesting that health beliefs embedded in different cultures and/or self-management needs of different client groups influence how people respond to the items. The purpose of this study was to examine how adults with cardiac conditions in Singapore interpreted and responded to the PAM-13, to investigate possible reasons for differences in responses and to propose solutions to overcome them. METHODS: We conducted retrospective cognitive interviews with 13 participants in an out-patient heart center. Interviews were transcribed and analyzed based on the framework approach to qualitative analysis. The four stages from Tourangeau's cognitive model were used as a framework to index the data from each item. RESULTS: There was variation in comprehension of questions leading to variation in responses. Comprehension issues were due to terms perceived by participants to be vague and the use of English terms uncommon in Singapore. Cultural influences impacted decision processes and problems with response processes of the self-rating Likert scale surfaced. CONCLUSIONS: This study reinforces the need to culturally adapt the tool, even when language translation is not necessary. Providing Likert scales with a larger number of may widen the relevance of PAM-13 in Singapore. Implications for rehabilitation Need to culturally adapt assessment tool, even when language translation is not necessary. Consider using Likert scales with a larger number of categories when using in Asian countries such as Singapore. Caution must be taken when using PAM-13 levels to decide interventions for each individual.

Complete Genome Sequence of the Bacterium Serratia marcescens SGAir0764, Isolated from Singapore Air.

Serratia marcescens strain SGAir0764 was isolated from a tropical air sample collected in Singapore. The complete genome, sequenced on the PacBio RS II platform, consists of one chromosome with 5.1 Mb and one plasmid with 76.4 kb. Genome annotation predicts 4,723 protein-coding genes, 89 tRNAs, and 22 rRNAs.

Genome Sequence of Bacillus velezensis SGAir0473, Isolated from Tropical Air Collected in Singapore.

Bacillus velezensis strain SGAir0473 (Firmicutes) was isolated from tropical air collected in Singapore. Its genome was assembled using short reads and single-molecule real-time sequencing and comprises one chromosome with 4.18 Mb. The genome consists of 3,937 protein-coding genes, 86 tRNAs, and 27 rRNAs.

Genome Sequence of Geobacillus thermoleovorans SGAir0734, Isolated from Singapore Air.

The thermophilic bacterium Geobacillus thermoleovorans was isolated from a tropical air sample collected in Singapore. The genome was sequenced on the PacBio RS II platform and consists of one chromosome with 3.6 Mb and one plasmid with 75 kb. The genome comprises 3,509 protein-coding genes, 88 tRNAs, and 27 rRNAs.