Constraining C iii] Emission in a Sample of Five Luminous z = 5.7 Galaxies

Recent observations have suggested that the CIII]$\lambda1907/1909$ emission lines could be alternative diagnostic lines for galaxies in the reionization epoch. We use the F128N narrowband filter on the Hubble Space Telescope's ($\it{HST}$) Wide Field Camera 3 (WFC3) to search for CIII] emission in a sample of five galaxies at z = 5.7 in the Subaru Deep Field and the Subaru/XMM-Newton Deep Field. Using the F128N narrowband imaging, together with the broadband imaging, we do not detect CIII] emission for the five galaxies with $J_{\rm{AB}}$ ranging from 24.10 -- 27.00 in our sample. For the brightest galaxy J132416.13+274411.6 in our sample (z = 5.70, $J_{\rm{AB}} = 24.10$), which has a significantly higher signal to noise, we report a CIII] flux of $3.34\pm1.81 \times 10^{-18}$ $\mathrm{erg\ s^{-1}\ cm^{-2}}$, which places a stringent 3-$\rm\sigma$ upper limit of $5.43\times 10^{-18}$ $\mathrm{erg\ s^{-1}\ cm^{-2}}$on CIII] flux and 6.57 \AA\ on the CIII] equivalent width. Using the stacked image, we put a 3-$\rm\sigma$upper limit on the mean CIII] flux of$\mathrm{2.55\times10^{-18}\ erg\ s^{-1}\ cm^{-2}}$, and a 3-$\rm\sigma$upper limit on the mean CIII] equivalent width of 4.20 {\AA} for this sample of galaxies at z = 5.70. Combined with strong CIII] detection reported among high-z galaxies in the literature, our observations suggest that the equivalent widths of CIII] from galaxies at z$>$ 5.70 exhibit a wide range of distribution. Our strong limits on CIII] emission could be used as a guide for future observations in the reionization epoch

Maximizing the Output of Large Sky Surveys: From the IGM to Milky-Way Dwarf Spheroidal Galaxies

The availability of large sky surveys, including the SDSS and DESI, have revolutionized research across various fields from the large-scale structure of the universe to the evolutionary historiesof the Milky Way and its satellite galaxies. In my thesis, I utilize machine learning methods to analyze the large datasets from SDSS and DESI. I first show new measurements of the mean transmitted flux in the hydrogen \lya\ and a measurement of the relative transmitted flux in \lyb. This measurement uses 27,008 quasar spectra from the Fourteenth Data Release (DR14) of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). The \tlya\ values show a smooth increase by a factor of 5 over the redshift range $z=2.4-4.4$. I then investigate the spatial distribution, kinematics and metallicity of the Draco and Sextans dwarf spheroidal galaxies using DESI data. For Draco, I find minimal evidence for an extended distribution of stars and conclude it has not been significantly tidally disturbed or undergone extensive tidal stripping. For Sextans, through 6D orbit integration, I identify 16 candidate extra-tidal stars and argue that Sextans may have had significant dynamical interactions, possibly with other dwarf galaxies before accretion by the Milky Way

A New Measurement of the Mean Transmitted Flux in the Lyman-alpha and Lyman-beta Forest

We present new measurements of the mean transmitted flux in the hydrogen Ly$\rm \alpha$ and a relative transmitted flux measurement in Ly$\rm \beta$ using 27,008 quasar spectra from the Fourteenth Data Release (DR14) of the Extended Baryon Oscillation Spectroscopic Survey (eBOSS). Individual spectra are first combined into 16 composites with mean redshifts in the range of $2.8<z<4.9$. We then apply Markov Chain Monte Carlo (MCMC) inference to produce a piecewise fit of the effective $\tau_{\rm{Ly\alpha}}$ (corrected for metal lines and optically thick absorption) assuming a spline point distribution. We also perform a relative $\Delta \tau_{\rm{Ly\beta}}$ measurement with the same data set, finding $\Delta \tau_{\rm{Ly\beta}}<0.35$ at $z<4.8$. The 6-8 $\%$ precision measurements in the rest frame 1075-1150 {\AA} at $\it{z} \ < \rm{4.0}$ and 10-12 $\%$ precision measurements in the same region at $\it{z} \ > \rm{4.0}$on$\tau_{\rm{Ly\alpha}}$, and our determinations of$\Delta \tau_{\rm{Ly\beta}}$, are dominated by systematic errors, likely arising from bias and uncertainties in estimates of the quasar continuum. Our$\tau_{\rm{Ly\alpha}}$values show a smooth increase by a factor of 5 over the redshift range$z=2.4-4.4$.Comment: Accepted by MNRA

Effect of Heat Shock Treatment on the Storage Quality of Fresh-Cut Lily Bulbs

In order to explore the effect of heat shock treatment (HT) on the storage quality of fresh-cut lily bulbs, changes in the quality characteristics of lily bulb slices (Lilium davidii var. unicolor Cotton) exposed to heat shock treatment (hot water at 55 ℃, 2 min) were examined during storage at 4 ℃. The results demonstrated that HT effectively maintained the color of fresh-cut lily bulbs during storage and preserved the cell wall structure. The activities of peroxidase (POD), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL) were suppressed by HT. Meanwhile, the accumulation of total phenolics (TP) and malondialdehyde (MDA) and the increase of relative electric conductivity (REC) were delayed, which led to reduced mass loss, decay rate, and browning degree. Comparison with the control group, the activities of POD, PPO and PAL in the HT group decreased by 95.26%, 21.74% and 41.65%, respectively. The decay rate, browning degree, MDA content, REC and TP content in the HT group were 10.56%, 1.55, 0.13 μmol/g, 19.71% and 3.51 mg/g, respectively, which were all significantly lower than those in the control group (P 0.05). Furthermore, plasma membrane dissolution did not appear in the HT group until the 40th day, which was 30 days later than the control group. Therefore, HT effectively delayed the quality deterioration of fresh-cut lily bulbs during storage and prolonged the storage time

Deep Hubble Space Telescope Imaging on the Extended Lyα\alpha Emission of a QSO at z=2.19z = 2.19 with Damped Lyman Alpha System as a Natural Coronagraph

Recent observations suggest that proximate damped Ly$\alpha$ (PDLA) systems can be used to study the host galaxies of Quasi-stellar objects (QSOs), because the PDLAs can block the bright point-spread-function (PSF) from central QSOs. Using six-orbits of narrowband imaging with $\it{HST}$/WFC3, we present the first high resolution narrowband image of the Ly$\alpha$ emission in the PDLA trough of the QSO SDSSJ115432.67-021537.9 . We detect one major component and one minor component in the narrowband imaging. Combining the $\it{HST}$/WFC3 imaging with deep Magellan/MagE spectra, we measure that the Ly$\alpha$ flux F$_{\rm{Ly\alpha}}$ = 1.56$\pm0.10 \times10^{-16}$ $\rm{erg\ s^{-1}\ cm^{-2}}$, which is among the luminous ($\approx$ 2.7 L$^{\star}_{\rm{Ly\alpha}}$) Ly$\alpha$ emitters at $\it{z} =$ 2.19. The $\rm{Ly\alpha}$-based star formation rate (SFR) is $\sim$ 7 \textrm{M_{\sun} \ yr^{-1}}. These observational results favor that the star formation from the host galaxy could be the main mechanism to power the Ly$\alpha$ emission. This new method sheds new light on the study of the kinematic structure and the spatial distribution of the extended Ly$\alpha$ emitting regions around the QSO host

Discovery of 16 new z ∼ 5.5 quasars: filling in the redshift gap of quasar color selection

We present initial results from the first systematic survey of luminous z ∼ 5.5 quasars. Quasars at z ∼ 5.5, the post-reionization epoch, are crucial tools to explore the evolution of intergalactic medium, quasar evolution, and the early super-massive black hole growth. However, it has been very challenging to select quasars at redshifts 5.3 ≤ z ≤ 5.7 using conventional color selections, due to their similar optical colors to late-type stars, especially M dwarfs, resulting in a glaring redshift gap in quasar redshift distributions. We develop a new selection technique for z ∼ 5.5 quasars based on optical, near-IR, and mid-IR photometric data from Sloan Digital Sky Survey (SDSS), UKIRT InfraRed Deep Sky Surveys—Large Area Survey (ULAS), VISTA Hemisphere Survey (VHS), and Wide Field Infrared Survey Explorer. From our pilot observations in the SDSS-ULAS/VHS area, we have discovered 15 new quasars at 5.3 ≤ z ≤ 5.7 and 6 new lower redshift quasars, with SDSS z band magnitude brighter than 20.5. Including other two z ∼ 5.5 quasars already published in our previous work, we now construct a uniform quasar sample at 5.3 ≤ z ≤ 5.7, with 17 quasars in a ∼4800 square degree survey area. For further application in a larger survey area, we apply our selection pipeline to do a test selection by using the new wide field J-band photometric data from a preliminary version of the UKIRT Hemisphere Survey (UHS). We successfully discover the first UHS selected z ∼ 5.5 quasar

Waste Clearance in the Brain

Waste clearance (WC) is an essential process for brain homeostasis, which is required for the proper and healthy functioning of all cerebrovascular and parenchymal brain cells. This review features our current understanding of brain WC, both within and external to the brain parenchyma. We describe the interplay of the blood-brain barrier (BBB), interstitial fluid (ISF), and perivascular spaces within the brain parenchyma for brain WC directly into the blood and/or cerebrospinal fluid (CSF). We also discuss the relevant role of the CSF and its exit routes in mediating WC. Recent discoveries of the glymphatic system and meningeal lymphatic vessels, and their relevance to brain WC are highlighted. Controversies related to brain WC research and potential future directions are presented

Variations in Cuticular Composition Characteristics among Pepper Varieties and Their Effects on Storage Quality

To investigate cuticular composition-storage quality correlations, nine pepper cultivars (Meiyan 9, Xingyue, Leitianyu 338, 595, M94, 4868, H21-4270, 33, T21-1) were analyzed for weight-loss rate, firmness, decay rate, total soluble solids, and capsaicinoids during 10 d storage at 25±0.50 ℃ with RH90%~95%. The changes in cuticle composition were analyzed by gas chromatography-mass spectrometry and correlation analyses between cuticular components and storage parameters were performed. The results showed that the quality of all varieties pepper deteriorated to varying extents after storage, manifested as water loss and wrinkling, the weight loss rate and decay rate increased respectively by 18.36%~37.84% and 6.67%~76.67%, and firmness decreased by 69.66~388.70 g. The capsaicinoids in different varieties pepper showed different changes after storage, except Meiyan 9, Xingyue, 4868 and 33, their content in other varieties increased by 0.03~0.62 g/kg dry weight after storage. The cuticular wax of pepper was mainly composed of fatty acids, alkanes, alcohols, and terpenoids, while the cutin monomer was mainly composed of fatty acids, alkanes, and alcohols. The total cuticular wax content decreased after storage except Xingyue, Meiyan 9, M94, and 4868, while the cutin monomer content decreased after storage except Leitianyu 338, Meiyan 9, and 4868. The cluster analysis showed that compared with other varieties, the comprehensive quality of Leitianyu 338, 595, T21-1 and M94 was relatively good, their low weight loss rate and high firmness and capsaicinoids content were suitable for processing and storage. The correlation analysis showed that alkane content in the cuticle of peppers had a positive effect on the maintenance of storage quality, it was positively correlated with firmness and capsaicinoids but negatively correlated with weight loss rate. This study would provide a theoretical basis for reasonable cultivation, screening, processing, and utilization of various varieties pepper in the later stage

Skeletal muscle-specific DJ-1 ablation-induced atrogenes expression and mitochondrial dysfunction contributing to muscular atrophy.

BACKGROUND: DJ-1 is a causative gene for Parkinsons disease. DJ-1-deficient mice develop gait-associated progressive behavioural abnormalities and hypoactive forearm grip strength. However, underlying activity mechanisms are not fully explored. METHODS: Western blotting and quantitative real-time polymerase chain reaction approaches were adopted to analyse DJ-1 expression in skeletal muscle from aged humans or mice and compared with young subjects. Skeletal muscle-specific-DJ-1 knockout (MDKO) mice were generated, followed by an assessment of the physical activity phenotypes (grip strength, maximal load capacity, and hanging, rotarod, and exercise capacity tests) of the MDKO and control mice on the chow diet. Muscular atrophy phenotypes (cross-sectional area and fibre types) were determined by imaging and quantitative real-time polymerase chain reaction. Mitochondrial function and skeletal muscle morphology were evaluated by oxygen consumption rate and electron microscopy, respectively. Tail suspension was applied to address disuse atrophy. RNA-seq analysis was performed to indicate molecular changes in muscles with DJ-1 ablation. Dual-luciferase reporter assays were employed to identify the promoter region of Trim63 and Fbxo32 genes, which were indirectly regulated by DJ-1 via the FoxO1 pathway. Cytoplasmic and nuclear fractions of DJ-1-deleted muscle cells were analysed by western blotting. Compound 23 was administered into the gastrocnemius muscle to mimic the of DJ-1 deletion effects. RESULTS: DJ-1 expression decreased in atrophied muscles of aged human (young men, n&nbsp;=&nbsp;2; old with aged men, n&nbsp;=&nbsp;2; young women, n&nbsp;=&nbsp;2; old with aged women, n&nbsp;=&nbsp;2) and immobilization mice (n&nbsp;=&nbsp;6, P&nbsp;&lt;&nbsp;0.01). MDKO mice exhibited no body weight difference compared with control mice on the chow diet (Flox, n&nbsp;=&nbsp;8; MDKO, n&nbsp;=&nbsp;9). DJ-1-deficient muscles were slightly dystrophic (Flox, n&nbsp;=&nbsp;7; MDKO, n&nbsp;=&nbsp;8; P&nbsp;&lt;&nbsp;0.05), with impaired physical activities and oxidative capacity (n&nbsp;=&nbsp;8, P&nbsp;&lt;&nbsp;0.01). In disuse-atrophic conditions, MDKO mice showed smaller cross-sectional area (n&nbsp;=&nbsp;5, P&nbsp;&lt;&nbsp;0.01) and more central nuclei than control mice (Flox, n&nbsp;=&nbsp;7; MDKO, n&nbsp;=&nbsp;6; P&nbsp;&lt;&nbsp;0.05), without alteration in muscle fibre types (Flox, n&nbsp;=&nbsp;6; MDKO, n&nbsp;=&nbsp;7). Biochemical analysis indicated that reduced mitochondrial function and upregulated of atrogenes induced these changes. Furthermore, RNA-seq analysis revealed enhanced activity of the FoxO1 signalling pathway in DJ-1-ablated muscles, which was responsible for the induction of atrogenes. Finally, compound 23 (an inhibitor of DJ-1) could mimic the effects of DJ-1 ablation in vivo. CONCLUSIONS: Our results illuminate the crucial of skeletal muscle DJ-1 in the regulation of catabolic signals from mechanical stimulation, providing a therapeutic target for muscle wasting diseases