IceCube is a kilometer-cubed neutrino detector located at the South Pole. IceCube is sensitive to sterile neutrinos in the range of the masses and mixing angles of the LSND/MiniBooNE anomaly (Δm2 ∼ 1 ...eV ). In this thesis, I am looking at upgoing atmospheric neutrinos ( that have traveled through the Earth from the Northern Hemisphere) with energies between 200 GeV to 20 TeV. I am trying to measure the changes in the distribution of neutrino energy versus the zenith angle, which reflects the distance that the neutrinos traveled through the Earth, due to the existence of sterile neutrinos. In the case of the 3 + 1 sterile neutrino model, a strong disappearance of muon antineutrinos and a weak disappearance of muon neutrinos is anticipated, due to MSW-resonant oscillation (or matter effect). This thesis focuses on the neutrino events that interact with ice and produce secondary muons within the detector boundaries. By analyzing these types of events, we get a measurement of energy that is superior to previous analyses that looked at muons regardless of whether they started within the detector. This thesis describes the process of data selection and the methods used in the sterile neutrino search and shows that the sensitivity to sterile neutrinos with lower Δm2 increases compared to previous analyses.
Fog computing-enhanced Internet of Things (IoT) has recently received considerable attention, as the fog devices deployed at the network edge can not only provide low latency, location awareness but ...also improve real-time and quality of services in IoT application scenarios. Privacy-preserving data aggregation is one of typical fog computing applications in IoT, and many privacy-preserving data aggregation schemes have been proposed in the past years. However, most of them only support data aggregation for homogeneous IoT devices, and cannot aggregate hybrid IoT devices' data into one in some real IoT applications. To address this challenge, in this paper, we present a lightweight privacy-preserving data aggregation scheme, called Lightweight Privacy-preserving Data Aggregation, for fog computing-enhanced IoT. The proposed LPDA is characterized by employing the homomorphic Paillier encryption, Chinese Remainder Theorem, and one-way hash chain techniques to not only aggregate hybrid IoT devices' data into one, but also early filter injected false data at the network edge. Detailed security analysis shows LPDA is really secure and privacy-enhanced with differential privacy techniques. In addition, extensive performance evaluations are conducted, and the results indicate LPDA is really lightweight in fog computing-enhanced IoT.
The application of non-target analysis (NTA), a comprehensive approach to characterize unknown chemicals, including chemicals of emerging concern has seen a steady increase recently. Given the ...relative novelty of this type of analysis, robust quality assurance and quality control (QA/QC) measures are imperative to ensure quality and consistency of results obtained using different workflows. Due to fundamental differences to established targeted workflows, new or expanded approaches are necessary; for example to minimize the risk of losing potential substances of interest (i.e. false negatives, Type II error). We present an overview of QA/QC techniques for NTA workflows published to date, specifically focusing on the analysis of environmental samples using liquid chromatography coupled to HRMS. From a QA/QC perspective, we discuss methods used for each step of analysis: sample preparation, chromatography, mass spectrometry, and data processing. We then finish with a series of recommendations to improve the quality assurance of NTA workflows.
•Non-target analysis needs specialised quality assurance approaches.•Current procedures focus mostly on specific parts of the workflow.•Loss of information (i.e. false negatives) occurs during all workflow steps.•Improvement of current quality assurance procedures is required.•Harmonization of the reporting practice of used approaches is essential.
Water resources are vulnerable to contamination from polar organic compounds (POCs) originating from sources such as wastewater effluent. Two configurations of a microporous polyethylene tube (MPT) ...passive sampler were investigated for the time-integrative detection and quantification of POCs in effluent. One configuration contained the polymeric reversed phase sorbent Strata-X (SX) and the other Strata-X suspended in agarose gel (SX-Gel). These were deployed for up to 29 days and analysed for forty-nine POCs including pesticides, pharmaceuticals and personal care products (PPCPs) together with illicit drugs. Complementary composite samples were collected on days 6, 12, 20 and 26 representing the previous 24 h. Thirty-eight contaminants were detected in composite samples and MPT extracts, with MPT sampling rates (Rs) for 11 pesticides and 9 PPCPs/drugs ranging from 0.81 to 10.32 mL d−1 in SX and 1.35–32.83 mL d−1 in SX-Gel. Half-times to equilibrium of contaminants with the SX and SX-Gel equipped samplers ranged from two days to >29 days. MPT (SX) samplers were also deployed at 10 wastewater treatment effluent discharge sites across Australia for 7 days (again with complementary composite samples), to validate the sampler performance under varying conditions. Extracts from these MPTs detected 48 contaminants in comparison with 46 in composite samples, with concentrations ranging from 0.1 to 138 ng mL−1. An advantage of the MPT was preconcentration of contaminants, resulting in extract levels often markedly above instrument analytical detection limits. The validation study demonstrated a high correlation between accumulated contaminant mass in the MPTs and wastewater concentrations from composite samples (r2 > 0.70, where concentrations in composite samples were > 3× LOD). The MPT sampler shows promise as a sensitive tool for detecting POCs at trace levels in wastewater effluent and also quantifying these levels if temporal concentration variations are not significant.
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•First deployment of microporous polyethylene tube samplers in wastewater effluent•2 configurations with different sorbents employed to target polar organic compounds.•38 pharmaceuticals, personal care products, pesticides, and drugs detected.•20 of these compounds were successfully calibrated enabling quantification.•Sampler validation performed in effluent of 10 different wastewater treatment sites.
Monitoring contamination from per- and polyfluoroalkyl substances (PFASs) in water systems impacted by aqueous film-forming foams (AFFFs) typically addresses a few known PFAS groups. Given the ...diversity of PFASs present in AFFFs, current analytical approaches do not comprehensively address the range of PFASs present in these systems. A suspect-screening and nontarget analysis (NTA) approach was developed and applied to identify novel PFASs in groundwater samples contaminated from historic AFFF use. A total of 88 PFASs were identified in both passive samplers and grab samples, and these were dominated by sulfonate derivatives and sulfonamide-derived precursors. Several ultrashort-chain (USC) PFASs (≤C3) were detected, 11 reported for the first time in Australian groundwater. Several transformation products were identified, including perfluoroalkane sulfonamides (FASAs) and perfluoroalkane sulfinates (PFASis). Two new PFASs were reported (((perfluorohexyl)sulfonyl)sulfamic acid; m/z 477.9068 and (E)-1,1,2,2,3,3,4,5,6,7,8,8,8-tridecafluorooct-6-ene-1-sulfonic acid; m/z 424.9482). This study highlights that several PFASs are overlooked using standard target analysis, and therefore, the potential risk from all PFASs present is likely to be underestimated.
Night vision in mammals depends fundamentally on rod photoreceptors and the well-studied rod bipolar (RB) cell pathway. The central neuron in this pathway, the AII amacrine cell (AC), exhibits a ...spatially tuned receptive field, composed of an excitatory center and an inhibitory surround, that propagates to ganglion cells, the retina's projection neurons. The circuitry underlying the surround of the AII, however, remains unresolved. Here, we combined structural, functional and optogenetic analyses of the mouse retina to discover that surround inhibition of the AII depends primarily on a single interneuron type, the NOS-1 AC: a multistratified, axon-bearing GABAergic cell, with dendrites in both ON and OFF synaptic layers, but with a pure ON (depolarizing) response to light. Our study demonstrates generally that novel neural circuits can be identified from targeted connectomic analyses and specifically that the NOS-1 AC mediates long-range inhibition during night vision and is a major element of the RB pathway.
The leaching of per- and polyfluoroalkyl substances (PFASs) from Australian firefighting training grounds has resulted in extensive contamination of groundwater and nearby farmlands. Humans, farm ...animals, and wildlife in these areas may have been exposed to complex mixtures of PFASs from aqueous film-forming foams (AFFFs). This study aimed to identify PFAS classes in pooled whole blood (n = 4) and serum (n = 4) from cattle exposed to AFFF-impacted groundwater and potentially discover new PFASs in blood. Thirty PFASs were identified at various levels of confidence (levels 1a–5a), including three novel compounds: (i) perfluorohexanesulfonamido 2-hydroxypropanoic acid (FHxSA-HOPrA), (ii) methyl((perfluorohexyl)sulfonyl)sulfuramidous acid, and (iii) methyl((perfluorooctyl)sulfonyl)sulfuramidous acid, belonging to two different classes. Biotransformation intermediate, perfluorohexanesulfonamido propanoic acid (FHxSA-PrA), hitherto unreported in biological samples, was detected in both whole blood and serum. Furthermore, perfluoroalkyl sulfonamides, including perfluoropropane sulfonamide (FPrSA), perfluorobutane sulfonamide (FBSA), and perfluorohexane sulfonamide (FHxSA) were predominantly detected in whole blood, suggesting that these accumulate in the cell fraction of blood. The suspect screening revealed several fluoroalkyl chain-substituted PFAS. The results suggest that targeting only the major PFASs in the plasma or serum of AFFF-exposed mammals likely underestimates the toxicological risks associated with exposure. Future studies of AFFF-exposed populations should include whole-blood analysis with high-resolution mass spectrometry to understand the true extent of PFAS exposure.
Because metabolites are hypothesized to play key roles as markers and effectors of cardiometabolic diseases, recent studies have sought to annotate the genetic determinants of circulating metabolite ...levels. We report a genome-wide association study (GWAS) of 217 plasma metabolites, including >100 not measured in prior GWAS, in 2076 participants of the Framingham Heart Study (FHS). For the majority of analytes, we find that estimated heritability explains >20% of interindividual variation, and that variation attributable to heritable factors is greater than that attributable to clinical factors. Further, we identify 31 genetic loci associated with plasma metabolites, including 23 that have not previously been reported. Importantly, we include GWAS results for all surveyed metabolites and demonstrate how this information highlights a role for AGXT2 in cholesterol ester and triacylglycerol metabolism. Thus, our study outlines the relative contributions of inherited and clinical factors on the plasma metabolome and provides a resource for metabolism research.
•Thirty-one genetic loci have associations with 64 distinct plasma metabolites•Heritability has a greater impact than clinical factors on metabolite variance•GWAS data for all metabolites (loci with p < 1.0 × 10−3) are provided as a resource•Integrating gene-metabolite data highlights a role for AGXT2 in lipid metabolism
Resistance to last resort antibiotics has been increasing, particularly in low- and middle-income countries such as Lebanon, which has well established challenges in antimicrobial stewardship and ...other public health and environmental issues. However, data on the emergence of antibiotic resistance in the community in Lebanon are limited. In this study, we assessed resistance to last resort antibiotics in the fecal samples of 111 otherwise healthy university students in north Lebanon. The results showed that 47.7% of the samples harbored extended-spectrum cephalosporin-resistant isolates, while 2.7% of the samples yielded colistin-resistant isolates. Furthermore, molecular analyses showed that the β-lactamase gene group,
group, was detected in the majority (93%) of screened extended-spectrum β-lactamase isolates. In addition, the colistin-resistant
isolates carried
, including the novel
variant, which was previously reported in clinical samples as well as in domesticated animals and the environment in Lebanon. Taken together, these findings highlight the occurrence of resistance to important antibiotics in the community, perhaps suggesting diffuse sources, including clinical and environmental settings, and multiple factors driving the spread of multidrug-resistant bacteria and resistance determinants. There is a pressing need for comprehensive antimicrobial stewardship programs and the implementation of evidence-based practices in clinical and community settings to mitigate the increasing spread of antimicrobial resistance.
As Europe's second longest river, the Danube is an important water source for drinking water and irrigation for many countries, before discharging into the Black Sea in the East. Per- and ...poly-fluoroalkyl substances (PFAS) have been observed over the last two decades in concentrations exceeding the European Union's drinking water guidelines for total sum of 20 select PFAS of 0.1 μg L−1. Their presence is a result of current and historical use and high environmental persistence, necessitating their monitoring for human risk assessments. The aim of this study is to use recently developed passive sampling technology to calculate time-integrated water concentrations and mass loads of 11 select PFAS at 9 sites along the Danube River. Results indicate ∑11 PFAS concentrations in the range of 9.3–29.6 ng L−1 were not in exceedance of EU drinking water guidelines, but perfluorooctanesulfonic acid (PFOS) was in exceedance of the environmental quality standard (0.65 ng L−1) at all sampling locations. The highest ∑11 PFAS mass loads were observed at Ruse (9.5 kg day−1) and Budapest (6.3 kg day−1), believed to be driven by proximity to industrial facilities and large populations (urban runoff). Finally, we estimate 4.9 kg of total PFAS (∑11 PFAS) were delivered to the Black Sea daily over Summer 2019.
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•PFAS were measured in surface waters of the Danube River by LC-MS/MS.•11 PFAS were detected in the Danube River. ∑11PFAS concentrations ranged 8–30 ng L−1.•4.9 kg of ∑11PFAS were delivered to the Black Sea daily during Summer 2019.•PFOS concentrations exceed the environmental quality standard at all sampling locations.•Passive sampling can be used for ongoing monitoring of PFAS for which calibration data is known.
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