Showing papers in "Elements in 2021"

Interventions to mitigate early spread of SARS-CoV-2 in Singapore: a modelling study

Abstract: Summary Background Since the coronavirus disease 2019 outbreak began in the Chinese city of Wuhan on Dec 31, 2019, 68 imported cases and 175 locally acquired infections have been reported in Singapore. We aimed to investigate options for early intervention in Singapore should local containment (eg, preventing disease spread through contact tracing efforts) be unsuccessful. Methods We adapted an influenza epidemic simulation model to estimate the likelihood of human-to-human transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a simulated Singaporean population. Using this model, we estimated the cumulative number of SARS-CoV-2 infections at 80 days, after detection of 100 cases of community transmission, under three infectivity scenarios (basic reproduction number [R0] of 1·5, 2·0, or 2·5) and assuming 7·5% of infections are asymptomatic. We first ran the model assuming no intervention was in place (baseline scenario), and then assessed the effect of four intervention scenarios compared with a baseline scenario on the size and progression of the outbreak for each R0 value. These scenarios included isolation measures for infected individuals and quarantining of family members (hereafter referred to as quarantine); quarantine plus school closure; quarantine plus workplace distancing; and quarantine, school closure, and workplace distancing (hereafter referred to as the combined intervention). We also did sensitivity analyses by altering the asymptomatic fraction of infections (22·7%, 30·0%, 40·0%, and 50·0%) to compare outbreak sizes under the same control measures. Findings For the baseline scenario, when R0 was 1·5, the median cumulative number of infections at day 80 was 279 000 (IQR 245 000–320 000), corresponding to 7·4% (IQR 6·5–8·5) of the resident population of Singapore. The median number of infections increased with higher infectivity: 727 000 cases (670 000–776 000) when R0 was 2·0, corresponding to 19·3% (17·8–20·6) of the Singaporean population, and 1 207 000 cases (1 164 000–1 249 000) when R0 was 2·5, corresponding to 32% (30·9–33·1) of the Singaporean population. Compared with the baseline scenario, the combined intervention was the most effective, reducing the estimated median number of infections by 99·3% (IQR 92·6–99·9) when R0 was 1·5, by 93·0% (81·5–99·7) when R0 was 2·0, and by 78·2% (59·0 −94·4) when R0 was 2·5. Assuming increasing asymptomatic fractions up to 50·0%, up to 277 000 infections were estimated to occur at day 80 with the combined intervention relative to 1800 for the baseline at R0 of 1·5. Interpretation Implementing the combined intervention of quarantining infected individuals and their family members, workplace distancing, and school closure once community transmission has been detected could substantially reduce the number of SARS-CoV-2 infections. We therefore recommend immediate deployment of this strategy if local secondary transmission is confirmed within Singapore. However, quarantine and workplace distancing should be prioritised over school closure because at this early stage, symptomatic children have higher withdrawal rates from school than do symptomatic adults from work. At higher asymptomatic proportions, intervention effectiveness might be substantially reduced requiring the need for effective case management and treatments, and preventive measures such as vaccines. Funding Singapore Ministry of Health, Singapore Population Health Improvement Centre.

Leveraging Twitter data to understand public sentiment for the COVID‐19 outbreak in Singapore

Abstract: Microblogging has become one of the most useful tools for sharing everyday life events and news and for expressing opinions about those events. As Twitter posts are short and constantly being generated, they are a great source for providing public sentiment towards events that occurred throughout the COVID-19 period in Singapore. In this project, we perform sentiment analysis and topic modeling on the tweets about COVID-19 in Singapore, from 1 February 2020 to 31 August 2020. We accomplished this by collecting tweets discussing about COVID-19 and geolocated as ‘Singapore’, using the Python library ‘SNSCRAPE’. We used the sentiments returned from the VADER lexicon-based classifier and emotions from pre-trained recurrent neural networks to find correlations between real-life events and sentiment changes throughout the whole period. From our analysis, we discovered an increase in tweets about COVID-19 during key periods such as the circuit breaker and found that the overall sentiment polarity was dominantly positive. However, emotion analysis revealed that there were changes in the prevalence of fear and joy emotions over time, due to real-life COVID-19 developments in Singapore. Additionally, sentiment polarity was found to differ from topic to topic.

Building occupancy and energy consumption: Case studies across building types

Abstract: Past research has shown that occupancy information can be used to reduce building energy consumption through occupant-based controls and by mitigating wasteful occupant behavior. In this study, we investigate the dynamic relationship between WiFi connection counts (as a proxy to occupancy) and building electricity consumption across four building typologies (office, lab, health center, and library). Our findings based on one year of data show a strong positive linear correlation between electricity consumption and WiFi count across all four building when the building is in operation. The data exploration also indicates higher interactions between occupants with the plug and lighting loads in office and lab space types as compared to in a health center and a library. Next, using principal component analysis (PCA) for feature extraction followed by Density-based spatial clustering of applications with noise (DBSCAN), we show that distinct clusters could be generated, characterized by an increase in the between-cluster variance and smaller within-cluster variation. Lastly, we apply linear regression to manifest how the clustering results can be used to better model the variables.

Codominant IgG and IgA expression with minimal vaccine mRNA in milk of BNT162b2 vaccinees

Abstract: Lactating women can produce protective antibodies in their milk after vaccination, which has informed antenatal vaccination programs for diseases such as influenza and pertussis. However, whether SARS-CoV-2-specific antibodies are produced in human milk as a result of COVID-19 vaccination is still unclear. In this study, we show that lactating mothers who received the BNT162b2 vaccine secreted SARS-CoV-2-specific IgA and IgG antibodies into milk, with the most significant increase at 3-7 days post-dose 2. Virus-specific IgG titers were stable out to 4-6 weeks after dose 2. In contrast, SARS-CoV-2-specific IgA levels showed substantial decay. Vaccine mRNA was detected in few milk samples (maximum of 2 ng/ml), indicative of minimal transfer. Additionally, infants who consumed post-vaccination human milk had no reported adverse effects up to 28 days post-ingestion. Our results define the safety and efficacy profiles of the vaccine in this demographic and provide initial evidence for protective immunity conferred by milk-borne SARS-CoV-2-specific antibodies. Taken together, our study supports recommendations for uninterrupted breastfeeding subsequent to mRNA vaccination against COVID-19.

Heat loss distribution: Impedance and thermal loss analyses in LiFePO4/graphite 18650 electrochemical cell

Abstract: We report here thermal behaviour and various components of heat loss of 18650-type LiFePO4/graphite cell at different testing conditions. In this regard, the total heat generated during charging and discharging processes at various current rates (C) has been quantified in an Accelerating Rate Calorimeter experiment. Irreversible heat generation, which depends on applied current and internal cell resistance, is measured under corresponding charge/discharge conditions using intermittent pulse techniques. On the other hand, reversible heat generation which depends on entropy changes of the electrode materials during the cell reaction is measured from the determination of entropic coefficient at various states of charge/discharge. The contributions of irreversible and reversible heat generation to the total heat generation at both high and low current rates are evaluated. At every state of charge/discharge, the nature of the cell reaction is found to be either exothermic or endothermic which is especially evident at low C rates. In addition, electrochemical impedance spectroscopy measurements are performed on above 18650 cells at various states of charge to determine the components of internal resistance. The findings from the impedance and thermal loss analysis are helpful for understanding the favourable states of charge/discharge for battery operation, and designing better thermal management systems.

Onco-fetal Reprogramming of Endothelial Cells Drives Immunosuppressive Macrophages in Hepatocellular Carcinoma

Abstract: We employed scRNA sequencing to extensively characterize the cellular landscape of human liver from development to disease. Analysis of ∼212,000 cells representing human fetal, hepatocellular carcinoma (HCC), and mouse liver revealed remarkable fetal-like reprogramming of the tumor microenvironment. Specifically, the HCC ecosystem displayed features reminiscent of fetal development, including re-emergence of fetal-associated endothelial cells (PLVAP/VEGFR2) and fetal-like (FOLR2) tumor-associated macrophages. In a cross-species comparative analysis, we discovered remarkable similarity between mouse embryonic, fetal-liver, and tumor macrophages. Spatial transcriptomics further revealed a shared onco-fetal ecosystem between fetal liver and HCC. Furthermore, gene regulatory analysis, spatial transcriptomics, and in vitro functional assays implicated VEGF and NOTCH signaling in maintaining onco-fetal ecosystem. Taken together, we report a shared immunosuppressive onco-fetal ecosystem in fetal liver and HCC. Our results unravel a previously unexplored onco-fetal reprogramming of the tumor ecosystem, provide novel targets for therapeutic interventions in HCC, and open avenues for identifying similar paradigms in other cancers and disease.

Ocean Subduction Dynamics in the Alps

Abstract: The Alps preserve abundant oceanic blueschists and eclogites that exemplify the selective preservation of fragments of relatively short-lived, small, slow-spreading North Atlantic–type ocean basins whose subducting slabs reach down to the Mantle Transition Zone at most. Whereas no subducted fragments were returned during the first half of the subduction history, those exhumed afterwards experienced conditions typical of mature subduction zones worldwide. Sedimentary-dominated units were under-plated intermittently, mostly at ~30–40 km depth. Some mafic–ultramafic-dominated units formed close to the continent were subducted to ~80 km and offscraped from the slab only a few million years before continental subduction. Spatiotemporal contrasts in burial and preservation of the fragments reveal how along-strike segmentation of the continental margin affects ocean subduction dynamics.

Pulsed electromagnetic fields synergize with graphene to enhance dental pulp stem cell-derived neurogenesis by selectively targeting trpc1 channels

Abstract: Conventional root canal treatment replaces the infected pulp with defined materials. Alternative cell-based tissue engineering strategies aim to regenerate a fully functional pulp within the root canal. Despite recent advances in this area, however, the regeneration of an innervated pulp remains a major challenge in the field. Both graphene (2DG) and pulsed electromagnetic fields (PEMFs) independently have been shown to promote diverse cellular developmental programs. The present study showed that 2DG promoted the neurogenic induction of human dental pulp stem cells (hDPSCs) by upregulating and accelerating the expression of mature neuronal markers. Notably, 2DG induced the highest expression of transient receptor potential canonical cation channel type 1 (TRPC1) during early neurogenesis. As brief PEMF exposure promotes in vitro differentiation by activating a TRPC1-mitochondrial axis, an opportunity to combine 2DG with developmentally targeted PEMF exposure for synergistic effects was realizable. Neurogenic gene expression, neurotransmitter release, and reactive oxygen species (ROS) production were greatly enhanced by a brief (10 min) and low amplitude (2 mT) PEMF exposure timed to coincide with the highest TRPC1 expression from hDPSCs on 2DG. In contrast, hDPSCs on glass were less responsive to PEMF exposure. The capacity of PEMFs to promote neurogenesis was precluded by the administration of penicillin/streptomycin, mirroring previous studies demonstrating that aminoglycoside antibiotics block TRPC1-mediated calcium entry and verifying the contribution of TRPC1 in this form of magnetoreception. Hence, graphene created a more conducive environment for subsequent PEMF-stimulated neurogenic induction of hDPSCs through their mutual capacity to activate TRPC1with subsequent ROS production.

Under Pressure: High-Pressure Metamorphism in the Alps

Abstract: The mechanisms attending the burial of crustal material and its exhumation before and during the Alpine orogeny are controversial. New mechanical models propose local pressure perturbations deviating from lithostatic pressure as a possible mechanism for creating (ultra-)high-pressure rocks in the Alps. These models challenge the assumption that metamorphic pressure can be used as a measure of depth, in this case implying deep subduction of metamorphic rocks beneath the Alpine orogen. We summarize petro-logical, geochronological and structural data to assess two fundamentally distinct mechanisms of forming (ultra-)high-pressure rocks: deep subduction; or anomalous, non-lithostatic pressure variation. Furthermore, we explore mineral-inclusion barometry to assess the relationship between pressure and depth in metamorphic rocks.

Development of a polymer-based antimicrobial coating for efficacious urinary catheter protection

Abstract: This study reports the development of a polymer-based catheter coating to facilitate controlled release of antimicrobial peptides (AMP) to target both planktonic bacteria and biofilm in the urinary catheter environment. Catheter associated urinary tract infection (CAUTI) is a common nosocomial infection among hospitalized patients and is a major reservoir of antimicrobial resistant pathogens. Although silver- or antibiotics-coated catheters have been deployed to minimise CAUTI, the inconsistency and lack of durability in antibacterial properties of these coatings have limited their clinical use. The incorporation of AMPs in catheter coatings has gained interest due to the effective bacteria killing effects of AMPs, with few reports on bacterial resistance development against peptides. This study aims to deploy a novel and potentially cost-effective technique to coat an anhydrous polymeric coating impregnated with AMPs for silicone-based catheters, to overcome limitations in conventional hydrogel-based coatings. Sustained peptide release was achieved with the development of an Ethyl Cellulose (EC): 1-Palmitoyl-2-oleoylphosphatidylcholine (POPC)-based diffusion layer over an AMP-laden Polycaprolactone (PCL)-based layer to control AMP diffusion into the environment over a clinically relevant duration. The ‘AMP-EC-PCL’ coating showed good anti-bacteria performance against uropathogenic Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa for up to 6 days. The coating also showed excellent anti-biofilm capability against green fluorescent protein (GFP)-tagged UTI E. coli. Fifteen centimeter catheter segments of single layer ‘AMP-EC-PCL’-coated catheters showed sustainable AMP release kinetics up to 7 days, where good antibacterial and anti-biofilm activity against E. coli was observed. The full scale ‘AMP-EC-PCL’-coated catheter showed improved mechanical integrity compared to commercial silicone catheters with preservation of the catheter balloon integrity upon expansion. Wound healing studies of the coated PDMS samples in mice models showed a reduction in bacteria concentration as compared to uncoated PDMS, indicating in vivo efficacy potential of the developed catheter coating platform.

Superhydrous Arc Magmas in the Alpine Context

Abstract: Magmatic rocks in the Alps are scarce. What little arc magmatism there was pre-dates the Eurasia–Adria collision at 43–34 Ma but ends at 30–29 Ma. Conversely, geochemical data for magmatic rocks from the Alps resemble that of subduction-related magmatic arcs. A characteristic of Alpine magmatism is the occurrence of relatively deep (80–100 km) super-hydrous (>8 wt% H2O) low-K primary magmas in the east and shoshonitic K-rich magmas in the west. These features are likely related to the absence of vigorous mantle wedge convection. Superhydrous primary magmas undergo extensive crystallization and fluid saturation at depth, producing high ratios of plutonic to volcanic rocks. We speculate that superhydrous primary arc magmas are a consequence of slow convergence and the initial architecture of subducting crust.

3D-Printed PCL/PPy Conductive Scaffolds as Three-Dimensional Porous Nerve Guide Conduits (NGCs) for Peripheral Nerve Injury Repair

Abstract: Conductivity is a desirable property of an ideal nerve guide conduit (NGC) that is being considered for peripheral nerve regeneration. Most of the conductive polymers reported in use for fabrication of tissue engineering scaffolds such as polypyrrole (PPy), polyaniline, polythiophene, and poly(3,4-ethylenedioxythiophene) are non-biodegradable and possess weak mechanical properties to be fabricated into 3D structures. In this study, a biodegradable and conductive block copolymer of PPy and Polycaprolactone (PPy-b-PCL) was used to fabricate 3D porous NGCs using a novel electrohydrodynamic jet 3D printing process which offers superior control over fiber diameter, pore size, porosity, and fiber alignment. PCL/PPy scaffolds with three different concentrations of PPy-b-PCL (0.5, 1, and 2% v/v) were fabricated as a mesh (pore size 125 ± 15 μm) and the effect of incorporation of PPy-b-PCL on mechanical properties, biodegradability, and conductivity of the NGCs were studied. The mechanical properties of the scaffolds decreased with the addition of PPy-b-PCL which aided the ability to fabricate softer scaffolds that are closer to the properties of the native human peripheral nerve. With increasing concentrations of PPy-b-PCL, the scaffolds displayed a marked increase in conductivity (ranging from 0.28 to 1.15 mS/cm depending on concentration of PPy). Human embryonic stem cell-derived neural crest stem cells (hESC-NCSCs) were used to investigate the impact of PPy-b-PCL based conductive scaffolds on the growth and differentiation to peripheral neuronal cells. The hESC-NCSCs were able to attach and differentiate to peripheral neurons on PCL and PCL/PPy scaffolds, in particular the PCL/PPy (1% v/v) scaffolds supported higher growth of neural cells and a stronger maturation of hESC-NCSCs to peripheral neuronal cells. Overall, these results suggest that PPy-based conductive scaffolds have potential clinical value as cell-free or cell-laden NGCs for peripheral neuronal regeneration.

Formation of the Alpine Orogen by Amagmatic Convergence and Assembly of Previously Rifted Lithosphere

Abstract: The tectonic and magmatic characteristics of the Alps and Pyrenees during convergence are quite distinct from characteristics associated with classic Benioff-type oceanic subduction. From the initiation of subduction at passive margins until the onset of continental collision, the closure of the Western Tethys never produced a long-lived magmatic arc. This is a consequence of the 3-D architecture of the Western Tethys (a series of hyper-thinned basins and continental blocks) and its narrow width (<500–700 km) prior to convergence. Subduction primarily involved the slow and amagmatic subduction of a narrow domain of dry lithospheric mantle. This type of congested Ampferer subduction led to the sequential and coherent accretion of inherited rifted domains which today form the Alpine and Pyrenean orogens.

Cilostazol for secondary stroke prevention: systematic review and meta-analysis.

Abstract: Background Stroke is one of the leading causes of death worldwide. Cilostazol, an antiplatelet and phosphodiesterase 3 inhibitor, has not been clearly established for ischaemic stroke use. We aim to determine the efficacy and safety of cilostazol for secondary stroke prevention. Methods MEDLINE, EMBASE, Cochrane Library, Web of Science and ClinicalTrials.gov were searched from inception to 25 September 2020, for randomised trials comparing the efficacy and safety of cilostazol monotherapy or dual therapy with another antiplatelet regimen or placebo, in patients with ischaemic stroke. Version 2 of the Cochrane risk-of-bias tool for randomised trials (RoB 2) was used to assess study quality. This meta-analysis was reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Results Eighteen randomised trials comprising 11 429 participants were included in this meta-analysis. Most trials possessed low risk of bias and were of low heterogeneity. Cilostazol significantly reduced the rate of ischaemic stroke recurrence (risk ratio, RR=0.69, 95% CI 0.58 to 0.81), any stroke recurrence (RR=0.64, 95% CI 0.54 to 0.74) and major adverse cardiovascular events (RR=0.67, 95% CI 0.56 to 0.81). Cilostazol did not significantly decrease mortality (RR=0.90, 95% CI 0.64 to 1.25) or increase the rate of good functional outcome (Modified Rankin Scale score of 0–1; RR=1.07, 95% CI 0.95 to 1.19). Cilostazol demonstrated favourable safety profile, significantly reducing the risk of intracranial haemorrhage (RR=0.46, 95% CI 0.31 to 0.68) and major haemorrhagic events (RR=0.49, 95% CI 0.34 to 0.70). Conclusions Cilostazol demonstrated superior efficacy and safety profiles compared with traditional antiplatelet regimens such as aspirin and clopidogrel for secondary stroke prevention but does not appear to affect functional outcomes. Future randomised trials can be conducted outside East Asia, or compare cilostazol with a wider range of antiplatelet agents.

Venus, An Active Planet: Evidence for Recent Volcanic and Tectonic Activity

Abstract: Similar in size to the Earth, Venus differs from our planet by its extreme surface temperature (470 °C), suffocating atmospheric pressure (about 92 times that of the Earth’s), and caustic atmosphere (mostly CO2, with sulfuric acid rain). Venus is Earth’s hellish twin sister. However, there are some similarities. As for the Earth, Venus has also had a very complex geologic history. During the early 1990s, NASA’s Magellan spacecraft imaged the surface of Venus with radar and gave us a panorama of a volcanic wonderland (Fig. 1). The surface of Venus is dotted with some of the largest volcanoes in the solar system, complete with summit calderas and extensive lava flows. Volcanoes on Venus resemble many of those on Earth, particularly those formed from the eruption of basaltic magma, such as Mauna Kea (Hawaii, USA) and Mount Etna (Italy). One of the biggest unresolved scientific questions about Venus concerns its style and rate of volcanism during its geologic past. Did volcanic eruptions on Venus occur locally and constantly in time? Or did the planet undergo sporadic events of global and catastrophic volcanism which rejuvenated its entire crust in a short amount of time?

The Heterogeneous Tethyan Oceanic Lithosphere of the Alpine Ophiolites

Abstract: The Alpine–Apennine ophiolites are lithospheric remnants of the Jurassic Alpine Tethys Ocean. They predominantly consist of exhumed mantle peridotites with lesser gabbroic and basaltic crust and are locally associated with continental crustal material, indicating formation in an environment transitional from an ultra-slow-spreading seafloor to a hyperextended passive margin. These ophiolites represent a unique window into mantle dynamics and crustal accretion in an ultra-slow-spreading extensional environment. Old, pre-Alpine, lithosphere is locally preserved within the mantle sequences: these have been largely modified by reaction with migrating asthenospheric melts. These reactions were active in both the mantle and the crust and have played a key role in creating the heterogeneous oceanic lithosphere in this branch of the Mesozoic Western Tethys.

Tales from the Underground: Speleothem Records of Past Hydroclimate

Abstract: Geochemical records from speleothems have significantly advanced our understanding of natural climate variability over the last ~600,000 years. Speleothems are sensitive recorders of past changes in hydroclimate because they can be precisely dated and contain multiple hydrologically sensitive geochemical proxies. Oxygen isotope records from speleothems tell us about the timing and mechanisms of past changes in precipitation amount, temperature, atmospheric circulation, and/or global monsoon intensity. Variations in speleothem carbon isotope ratios or trace element concentrations reflect changes in local water balance, vegetation, and karst hydrology. Speleothem paleoclimate records represent a window into the past that can provide crucial information for understanding how anthropogenic climate change and natural climate variability will impact future water resources on Earth.

IL6R-STAT3-ADAR1 (P150) interplay promotes oncogenicity in multiple myeloma with 1q21 amplification

Abstract: 1q21 amplification is an important prognostic marker in multiple myeloma. In this study we identified that IL6R (the interleukin-6 membrane receptor) and ADAR1 (an RNA editing enzyme) are critical genes located within the minimally amplified 1q21 region. Loss of individual genes caused suppression to the oncogenic phenotypes, the magnitude of which was enhanced when both genes were concomitantly lost. Mechanistically, IL6R and ADAR1 collaborated to induce a hyper-activation of the oncogenic STAT3 pathway. High IL6R confers hypersensitivity to interleukin-6 binding, whereas, ADAR1 forms a constitutive feed-forward loop with STAT3 in a P150-isoform-predominant manner. In this respect, ADAR1-P150 acts as a direct transcriptional target for STAT3 and this STAT3-induced-P150 in turn directly interacts with and stabilizes the former protein, leading to a larger pool of proteins acting as oncogenic transcription factors for pro-survival genes. The importance of both IL6R and ADAR1-P150 in STAT3 signaling was further validated when concomitant knockdown of both genes impeded IL6-induced-STAT3 pathway activation. Clinical evaluation of various datasets of myeloma patients showed that low expression of either one or both genes was closely associated with a compromised STAT3 signature, confirming the involvement of IL6R and ADAR1 in the STAT3 pathway and underscoring their essential role in disease pathogenesis. In summary, our findings highlight the complexity of the STAT3 pathway in myeloma, in association with 1q21 amplification. This study therefore reveals a novel perspective on 1q21 abnormalities in myeloma and a potential therapeutic target for this cohort of high-risk patients.

Temperature Reconstructions Using Speleothems

Abstract: Methods for reconstructing past temperatures from speleothems have only recently been developed. Advances in quantitative temperature proxies for speleothems are now allowing critical knowledge gaps to be filled, given the outstanding age control and wide geographical distribution of the speleothem archive. The methods of reconstructing temperatures from speleothems are diverse: they rely on concepts from geochemistry, biology, and physics, and are based on different aspects of speleothems, including water inclusions, calcite, and organic molecules. Combining the different approaches makes temperature reconstructions more robust, affords further insights into the methodologies, and provides constraints on other climate variables.

Cave Decorating with Microbes: Geomicrobiology of Caves

Abstract: Microorganisms are important for the formation and biogeochemistry of caves. Some caves are energy-rich systems with abundant organic or inorganic chemical energy inputs that support robust microbial ecosystems, but most are extremely oligotrophic settings with slow-growing microbial communities that rely on limited energy resources. Microorganisms are catalysts for element cycling in subterranean environments and act as agents of mineral precipitation and dissolution. Microbes can contribute to cave formation by producing acids and corroding limestone bedrock, and they can form secondary mineral deposits by catalyzing metal oxidation and inducing carbonate precipitation. We describe the energy sources for microbial life in caves, and we review three situations in which microorganisms may play a direct role in mineral deposition and bedrock corrosion.

Self-Efficacy in a Nursing Context

Abstract: Self-efficacy is one of the most ubiquitous term found in social, psychological, counselling, education, clinical and health literatures. The purpose of this chapter is to describe and evaluate self-efficacy theory and the studies most relevant to the nursing context. This chapter provides an overview of the development of self-efficacy theory, its five components and the role of self-efficacy in promoting emotional and behavioural changes in a person’s life with health problems. This chapter also discusses the role of self-efficacy in nursing interventions by providing examples of studies conducted in health promotion in patients and academic performance of nursing students.

Where is the Hydrogen

Abstract: How is hydrogen distributed among minerals and how is it bonded in their crystal structures? These are important questions, because the amount of hydrogen and the bonding configuration of hydrogen in crystalline materials governs many of that material’s properties: its thermal and compressional behavior, P–T phase stability, rheology, and electrical conductivity. A reliable reconstruction of the Earth’s interior, or the prediction of mineral transformations in complex industrial processes, must account for these parameters. Neutron diffraction can locate hydrogen sites in mineral structures, reveal any static or dynamic hydrogen disorder, help define the libration regime of hydrogen, and elucidate hydrogen-bonding configurations. Thus, that most elusive element for X-ray probes is perfectly detectable using neutrons.