Detection of vapor phase mercury species by laser fluorescence methods

Elemental and compound mercury are often both volatile and air stable. Several mercury species emissions have been identified in off-gases from industrial processes. The high toxicity of mercury species and the presence of mercury species in municipal waste and coal have prompted a demand for a cost-effective, accurate, and rugged technique for real-time, continuous detection of mercury species vapors. Real-time, continuous emission measurements are important for process control, monitoring, and remediation. At present, there is no commercial continuous emission monitoring (CEM) technique or instrumentation to reliably monitor volatile mercury species emissions from industrial stacks. Conventional measurement methods, such as cold vapor trap based techniques for elemental mercury, have difficulty in achieving both high sensitivity and the fast time resolution required for real-time monitoring. This doctoral research work gives a systematic study of potential methods for real-time trace detection of volatile elemental mercury and mercury compounds in industrial stack gases. It is based on laser-induced fluorescence techniques; photofragment fluorescence spectroscopy for detection of volatile mercury compounds, and resonance fluorescence for detection of elemental mercury. The capabilities and limitations of these detection techniques are investigated in this dissertation. Detection of mercury compounds is a challenge since they are non-fluorescent. With photofragment fluorescence spectroscopy, target Compound concentrations are related to the fluorescence intensity from an excited fragment. In this doctoral research work, low concentrations of mercuric bromide vapor in an atmospheric pressure flow cell are irradiated by a focused laser beam at 222nm. Photofragment fluorescence is monitored at 253.7nm. Two detection schemes, Charge Coupled Device (CCD) photomultiplier tube (PMT), are applied for the measurement of photofragment fluorescence. The performances of these two systems are compared in the dissertation. A supersonic jet is combined with resonance fluorescence for detection of elemental mercury vapor. With test gas expanded into a vacuum, fluorescence quenching and spectral broadening are reduced. In the experiment, the gas jet is crossed with a laser beam at 253.7nm to excite atomic fluorescence, which is distinguished from the elastic background by time gating. The performance characteristics of this measurement technique, including limit of detection, range of linearity, relative accuracy, and response time, are investigated. In addition, an ultraviolet (UV) interferometer is presented in this dissertation as a spectral discriminator for detection of Hg resonance fluorescence from elastic background. Its capabilities and limitations are discussed. A few suggestions regarding improvement on the current experimental system and measurement techniques for industrial applications of mercury detection are addressed

Heat Shock Protein 70 Inhibits the Activity of Influenza A Virus Ribonucleoprotein and Blocks the Replication of Virus In Vitro and In Vivo

BACKGROUND: Heat shock protein 70 (Hsp70) was identified as a cellular interaction partner of the influenza virus ribonucleoprotein (RNP) complex. The biological significance of the interaction between Hsp70 and RNP has not been fully investigated. PRINCIPAL FINDINGS: Here we demonstrated that Hsp70 was involved in the regulation of influenza A viral transcription and replication. It was found that Hsp70 was associated with viral RNP by directly interacting with the PB1 and PB2 subunits, and the ATPase domain of Hsp70 was required for the association. Immunofluorescence analysis showed that Hsp70 was translocated from the cytoplasm into the nucleus in infected cells. Then we found that Hsp70 negatively regulated the expression of viral proteins in infected cells. Real-time PCR analysis revealed that the transcription and replication of all eight viral segments were significantly reduced in Hsp70 overexpressed cells and greatly increased as Hsp70 was knocked down by RNA interference. Luciferase assay showed that overexpression of Hsp70 could inhibit the viral RNP activity on both vRNA and cRNA promoters. Biochemical analysis demonstrated that Hsp70 interfered with the integrity of RNP. Furthermore, delivered Hsp70 could inhibit the replication of influenza A virus in mice. SIGNIFICANCE: Our study indicated that Hsp70 interacted with PB1 and PB2 of RNP and could interfere with the integrity of RNP and block the virus replication in vitro and in vivo possibly through disrupting the binding of viral polymerase with viral RNA

Association between Nine Types of TCM Constitution and Five Chronic Diseases: A Correspondence Analysis Based on a Sample of 2,660 Participants

Objective. The purpose of this study was to explore the association of nine types of Traditional Chinese Medicine (TCM) constitution with the five chronic diseases: hypertension, hyperlipidemia, diabetes mellitus, heart disease, and obesity. Methods. Chi-squared test was performed to investigate the distribution characteristics of TCM constitutions in the participants with the five chronic diseases in questionnaire. Correspondence analysis was used to explore the correlation between them. Results. A total of 2,660 participants (1,400 males; 1,260 females) were included in this study. The mean age was 52.54 ± 13.92. Of them, 600 were of gentleness type accounting for 22.56%. Proportions of gentleness type in the chronic diseases (16.00%~23.70%) were less than that in general population (32.14%). The gentleness type and yin-deficiency type were significantly correlated with hypertension and diabetes mellitus, qi-deficiency type was correlated with heart disease, phlegm-dampness type was associated with obesity, and dampness-heat type was correlated with hyperlipidemia. Conclusions. The correlations between TCM constitution types and the five chronic diseases were different. This may have a significant implication for TCM practice, and even the people with gentleness type should not be ignored in health management

Longitudinal changes of lactopontin (milk osteopontin) in term and preterm human milk

BackgroundLactopontin (LPN) in breast milk, also known as milk osteopontin is thought to play a myriad of important roles in infants when they are immature. The purpose of the present study was to examine the longitudinal changes in LPN concentrations in term and preterm milk, and elucidate the links between maternal characteristics, LPN levels, and child growth in a birth cohort.Methods131 mothers who delivered term, moderate-late preterm (MPT), very preterm (VPT), and extremely preterm (EPT) infants were included, milk samples were collected at 7, 14, 28, and 120 days postpartum. LPN concentration was determined by multiple reaction monitoring (MRM) using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).ResultsOur results indicated that LPN change over time of VPT (P = 0.024) and EPT (P = 0.003) were significantly different from term milk, although they all gradually decreased with lactation. In terms of LPN-related factors, maternal age was a significant contributor in late mature milk and pre-pregnancy BMI a significant contributor to colostrum and transitional milk. We further investigated relationships between LPN levels and infant weight and our results suggested that high levels of LPN in breast milk might be useful for the catch-up growth of infants.ConclusionLPN levels in breast milk are related to maternal factors, and differences in LPN levels may affect the growth of infants. As milk is a critical part in the mother–breastmilk–infant “triad,” the association between maternal-infant factors and milk LPN levels warrants further study

A multicenter, randomized controlled, non-inferiority trial, comparing nasal continuous positive airway pressure with nasal intermittent positive pressure ventilation as primary support before minimally invasive surfactant administration for preterm infants with respiratory distress syndrome (the NIV-MISA-RDS trial): Study protocol

BackgroundNon-invasive ventilation (NIV) treatment has been developed to minimize lung damage and to avoid invasive mechanical ventilation (IMV) in preterm infants, especially in those with a gestational age of <30 weeks. Our hypothesis is that for preterm infants <30 weeks with potential to develop respiratory distress syndrome (RDS), nasal continuous positive airway pressure (NCPAP) is non-inferior to the nasal intermittent positive pressure ventilation (NIPPV) as primary respiratory support before minimal invasive surfactant administration (MISA).Methods and designThe NIV-MISA-RDS trial is planned as an unblinded, multicenter, randomized, non-inferiority trial at 14 tertiary neonatal intensive care units (NICUs) in China. Eligible infants are preterm infants of 24–29+6 weeks of gestational age who have spontaneous breaths at birth and require primary NIV support for RDS. Infants are randomized 1:1 to treatment with either NCPAP or NIPPV once admitted into NICUs. If an infant presents progressively aggravated respiratory distress and is clinically diagnosed as having RDS, pulmonary surfactant will be supplemented by MISA in the first 2 h of life. The primary outcome is NIV treatment failure within 72 h after birth. With a specified non-inferiority margin of 10%, using a two-sided 95% CI and 80% power, the study requires 480 infants per group (in total 960 infants).DiscussionCurrent evidence shows that NIV and MISA may be the most effective strategy for minimizing IMV in preterm infants with RDS. However, there are few large randomized controlled trials to compare the effectiveness of NCPAP and NIPPV as the primary respiratory support after birth and before surfactant administration. We will conduct this trial to test the hypothesis that NCPAP is not inferior to NIPPV as the initial respiratory support in reducing the use of IMV in premature infants who have spontaneous breaths after birth and who do not require intubation in the first 2 h after birth. The study will provide clinical data for the selection of the initial non-invasive ventilation mode in preterm infants with a gestational age of <30 weeks with spontaneous breaths after birth.Clinical trial registrationhttps://register.clinicaltrials.gov, identifier: NCT05137340

Autophagy Induction by HIV-Tat and Methamphetamine in Primary Midbrain Neuronal Cells of Tree Shrews via the mTOR Signaling and ATG5/ATG7 Pathway

Background: Addictive stimulant drugs, such as methamphetamine (METH), increase the risk of exposure to the human immunodeficiency virus-1 (HIV-1) infection and thus predispose individuals to the development of HIV-associated neurocognitive disorders (HANDs). Previous studies have indicated that HIV-Tat (the transactivator of transcription) and METH can synergistically induce autophagy in SH-SY5Y neuroblastoma cells and that autophagy plays a pivotal role in the neuronal dysfunction in HANDs. However, the underlying mechanism of METH-and HIV-Tat-induced neuronal autophagy remains unclear.Methods: We cultured primary midbrain neuronal cells of tree shrews and treated them with METH and HIV-Tat to study the role of METH and HIV-Tat in inducing autophagy. We evaluated the effects of the single or combined treatment of METH and HIV-Tat on the protein expressions of the autophagy-related genes, including Beclin-1 and LC3B, ATG5, and ATG7 in METH and HIV-Tat-induced autophagy. In addition, the presence of autophagosomes in the METH and/or HIV-Tat treatment was revealed using transmission electron microscopy.Results: The results indicated that METH increased the protein levels of LC3B and Beclin-1, and these effects were significantly enhanced by HIV-Tat. Moreover, the results suggested that ATG5 and ATG7 were involved in the METH and HIV-Tat-induced autophagy. In addition, it was found that mTOR inhibition via pharmacological intervention could trigger autophagy and promote METH and HIV-Tat-induced autophagy.Discussion: Overall, this study contributes to the knowledge of the molecular underpinnings of METH and HIV-Tat-induced autophagy in primary midbrain neuronal cells. Our findings may facilitate the development of therapeutic strategies for METH-and HIV-Tat-induced autophagy in HANDs

TRIB1 confers therapeutic resistance in GBM cells by activating the ERK and Akt pathways

GBM (Glioblastoma) is the most lethal CNS (Central nervous system) tumor in adults, which inevitably develops resistance to standard treatments leading to recurrence and mortality. TRIB1 is a serine/threonine pseudokinase which functions as a scaffold platform that initiates degradation of its substrates like C/EBPα through the ubiquitin proteasome system and also activates MEK and Akt signaling. We found that increased TRIB1 gene expression associated with worse overall survival of GBM patients across multiple cohorts. Importantly, overexpression of TRIB1 decreased RT/TMZ (radiation therapy/temozolomide)-induced apoptosis in patient derived GBM cell lines in vitro. TRIB1 directly bound to MEK and Akt and increased ERK and Akt phosphorylation/activation. We also found that TRIB1 protein expression was maximal during G2/M transition of cell cycle in GBM cells. Furthermore, TRIB1 bound directly to HDAC1 and p53. Importantly, mice bearing TRIB1 overexpressing tumors had worse overall survival. Collectively, these data suggest that TRIB1 induces resistance of GBM cells to RT/TMZ treatments by activating the cell proliferation and survival pathways thus providing an opportunity for developing new targeted therapeutics

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO