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1.
Cell ; 177(2): 478-491.e20, 2019 04 04.
Artículo en Inglés | MEDLINE | ID: mdl-30929901

RESUMEN

Genomic studies have identified hundreds of candidate genes near loci associated with risk for schizophrenia. To define candidates and their functions, we mutated zebrafish orthologs of 132 human schizophrenia-associated genes. We created a phenotype atlas consisting of whole-brain activity maps, brain structural differences, and profiles of behavioral abnormalities. Phenotypes were diverse but specific, including altered forebrain development and decreased prepulse inhibition. Exploration of these datasets identified promising candidates in more than 10 gene-rich regions, including the magnesium transporter cnnm2 and the translational repressor gigyf2, and revealed shared anatomical sites of activity differences, including the pallium, hypothalamus, and tectum. Single-cell RNA sequencing uncovered an essential role for the understudied transcription factor znf536 in the development of forebrain neurons implicated in social behavior and stress. This phenotypic landscape of schizophrenia-associated genes prioritizes more than 30 candidates for further study and provides hypotheses to bridge the divide between genetic association and biological mechanism.


Asunto(s)
Esquizofrenia/genética , Esquizofrenia/fisiopatología , Animales , Encéfalo , Corteza Cerebral , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/genética , Predisposición Genética a la Enfermedad , Estudio de Asociación del Genoma Completo , Fenotipo , Polimorfismo de Nucleótido Simple/genética , Pez Cebra/genética
2.
Genes Dev ; 36(3-4): 133-148, 2022 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-35086862

RESUMEN

The regeneration of peripheral nerves is guided by regeneration tracks formed through an interplay of many cell types, but the underlying signaling pathways remain unclear. Here, we demonstrate that macrophages are mobilized ahead of Schwann cells in the nerve bridge after transection injury to participate in building regeneration tracks. This requires the function of guidance receptor Plexin-B2, which is robustly up-regulated in infiltrating macrophages in injured nerves. Conditional deletion of Plexin-B2 in myeloid lineage resulted in not only macrophage misalignment but also matrix disarray and Schwann cell disorganization, leading to misguided axons and delayed functional recovery. Plexin-B2 is not required for macrophage recruitment or activation but enables macrophages to steer clear of colliding axons, in particular the growth cones at the tip of regenerating axons, leading to parallel alignment postcollision. Together, our studies unveil a novel reparative function of macrophages and the importance of Plexin-B2-mediated collision-dependent contact avoidance between macrophages and regenerating axons in forming regeneration tracks during peripheral nerve regeneration.


Asunto(s)
Regeneración Nerviosa , Nervios Periféricos , Axones/fisiología , Moléculas de Adhesión Celular , Macrófagos/metabolismo , Regeneración Nerviosa/genética , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Nervios Periféricos/metabolismo , Células de Schwann/metabolismo
3.
PLoS Biol ; 22(3): e3002528, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38427710

RESUMEN

Streptomyces antibiotic regulatory proteins (SARPs) are widely distributed activators of antibiotic biosynthesis. Streptomyces coelicolor AfsR is an SARP regulator with an additional nucleotide-binding oligomerization domain (NOD) and a tetratricopeptide repeat (TPR) domain. Here, we present cryo-electron microscopy (cryo-EM) structures and in vitro assays to demonstrate how the SARP domain activates transcription and how it is modulated by NOD and TPR domains. The structures of transcription initiation complexes (TICs) show that the SARP domain forms a side-by-side dimer to simultaneously engage the afs box overlapping the -35 element and the σHrdB region 4 (R4), resembling a sigma adaptation mechanism. The SARP extensively interacts with the subunits of the RNA polymerase (RNAP) core enzyme including the ß-flap tip helix (FTH), the ß' zinc-binding domain (ZBD), and the highly flexible C-terminal domain of the α subunit (αCTD). Transcription assays of full-length AfsR and truncated proteins reveal the inhibitory effect of NOD and TPR on SARP transcription activation, which can be eliminated by ATP binding. In vitro phosphorylation hardly affects transcription activation of AfsR, but counteracts the disinhibition of ATP binding. Overall, our results present a detailed molecular view of how AfsR serves to activate transcription.


Asunto(s)
Proteínas de Unión al ADN , Streptomyces , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Streptomyces/genética , Streptomyces/metabolismo , Microscopía por Crioelectrón , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Activación Transcripcional , Antibacterianos , Adenosina Trifosfato/metabolismo , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica
4.
Biochem Biophys Res Commun ; 718: 150037, 2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-38735135

RESUMEN

BACKGROUND: Non-small cell lung cancer (NSCLC) accounts for more than 80 % of lung cancer (LC) cases, making it the primary cause of cancer-related mortality worldwide. T-box transcription factor 5 (TBX5) is an important regulator of embryonic and organ development and plays a key role in cancer development. Here, our objective was to investigate the involvement of TBX5 in ferroptosis within LC cells and the underlying mechanisms. METHODS: First, TBX5 expression was examined in human LC cells. Next, overexpression of TBX5 and Yes1-associated transcriptional regulator (YAP1) and knockdown of TEA domain 1 (TEAD1) were performed in A549 and NCI-H1703 cells. The proliferation ability of A549 and NCI-H1703 cells, GSH, MDA, ROS, and Fe2+ levels were measured. Co-immunoprecipitation (Co-IP) was performed to verify whether TBX5 protein could bind YAP1. Then TBX5, YAP1, TEAD1, GPX4, p53, FTH1, SLC7A11 and PTGS2 protein levels were assessed. Finally, we verified the effect of TBX5 on ferroptosis in LC cells in vivo. RESULTS: TBX5 expression was down-regulated in LC cells, especially in A549 and NCI-H1703 cells. Overexpression of TBX5 significantly decreased proliferation ability of A549 and NCI-H1703 cells, downregulated GPX4 and GSH levels, and upregulated MDA, ROS, and Fe2+ levels. Co-IP verified that TBX5 protein could bind YAP1. Moreover, oe-YAP1 promoted proliferation ability of A549 and NCI-H1703 cells transfected with Lv-TBX5, upregulated GPX4 and GSH levels and downregulated MDA, ROS, and Fe2+ levels. Additionally, oe-YAP1 promoted FTH1 and SLC7A11 levels and inhibited p53 and PTGS2 levels in A549 and NCI-H1703 cells transfected with Lv-TBX5. However, transfection with si-TEAD1 further reversed these effects. In vivo experiments further validated that TBX5 promoted ferroptosis in LC cells. CONCLUSIONS: TBX5 inhibited the activation of YAP1-TEAD1 pathway to promote ferroptosis in LC cells.


Asunto(s)
Ferroptosis , Neoplasias Pulmonares , Proteínas de Dominio T Box , Factores de Transcripción de Dominio TEA , Factores de Transcripción , Proteínas Señalizadoras YAP , Ferroptosis/genética , Humanos , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Neoplasias Pulmonares/genética , Proteínas Señalizadoras YAP/metabolismo , Proteínas Señalizadoras YAP/genética , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Factores de Transcripción de Dominio TEA/metabolismo , Proteínas de Dominio T Box/metabolismo , Proteínas de Dominio T Box/genética , Animales , Línea Celular Tumoral , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Carcinoma de Pulmón de Células no Pequeñas/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Ratones Desnudos , Proliferación Celular , Proteínas de Unión al ADN/metabolismo , Proteínas de Unión al ADN/genética , Ratones , Regulación Neoplásica de la Expresión Génica , Células A549 , Transducción de Señal , Especies Reactivas de Oxígeno/metabolismo
5.
Nanotechnology ; 35(21)2024 Mar 04.
Artículo en Inglés | MEDLINE | ID: mdl-38320325

RESUMEN

Metasurface is a new type of micro-optical element developed in recent years. It can intelligently modulate electromagnetic waves by adjusting the geometrical parameters and arrangement of dielectric structures. In this paper, a bifocal metalens based on modulation of propagation phase was designed for the potential application in displacement measurement. The phase of the bifocal lens is designed by the optical holography-like method, which is verified by the scalar diffraction theory. We designed a square aperture lens with a side length of 200µm to realize two focal spots with focal lengths of 900 and 1100µm. The two focal spots aren't on one optical axis. The polarization insensitive TiO2cylinders are chosen as structure units. Four structures with different radius were selected to achieve the four phase steps. We fabricated the designed bifocal metalens using electron beam lithography and atomic layer deposition techniques, and measured the light intensity in the areas near the two foci in the direction of the longitudinal axis. The differential signal was calculated, from which we obtained a linear interval. It demonstrates the ability of bifocal differential measurement to be applied to displacement measurement. Because the metasurfaces production process is semiconductor compatible, the bifocal lens is easy to integrate and can be used for miniaturized displacement measurements, micro-resonators, acceleration measurements, and so on.

6.
Nucleic Acids Res ; 50(14): 8363-8376, 2022 08 12.
Artículo en Inglés | MEDLINE | ID: mdl-35871291

RESUMEN

Streptomyces coelicolor (Sc) is a model organism of actinobacteria to study morphological differentiation and production of bioactive metabolites. Sc zinc uptake regulator (Zur) affects both processes by controlling zinc homeostasis. It activates transcription by binding to palindromic Zur-box sequences upstream of -35 elements. Here we deciphered the molecular mechanism by which ScZur interacts with promoter DNA and Sc RNA polymerase (RNAP) by cryo-EM structures and biochemical assays. The ScZur-DNA structures reveal a sequential and cooperative binding of three ScZur dimers surrounding a Zur-box spaced 8 nt upstream from a -35 element. The ScRNAPσHrdB-Zur-DNA structures define protein-protein and protein-DNA interactions involved in the principal housekeeping σHrdB-dependent transcription initiation from a noncanonical promoter with a -10 element lacking the critical adenine residue at position -11 and a TTGCCC -35 element deviating from the canonical TTGACA motif. ScZur interacts with the C-terminal domain of ScRNAP α subunit (αCTD) in a complex structure trapped in an active conformation. Key ScZur-αCTD interfacial residues accounting for ScZur-dependent transcription activation were confirmed by mutational studies. Together, our structural and biochemical results provide a comprehensive model for transcription activation of Zur family regulators.


Asunto(s)
Proteínas Bacterianas , Proteínas de Unión al ADN , Streptomyces coelicolor , Activación Transcripcional , Proteínas Bacterianas/metabolismo , ADN Bacteriano/química , Proteínas de Unión al ADN/metabolismo , ARN Polimerasas Dirigidas por ADN/metabolismo , Regulación Bacteriana de la Expresión Génica , Conformación de Ácido Nucleico , Regiones Promotoras Genéticas , Streptomyces coelicolor/metabolismo , Zinc/metabolismo
7.
Environ Geochem Health ; 46(5): 163, 2024 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-38592574

RESUMEN

Microplastics leaching from aging biodegradable plastics pose potential environmental threats. This study used response surface methodology (RSM) to investigate the impact of temperature, light, and humidity on the aging characteristics of polylactic acid (PLA). Key evaluation metrics included the C/O ratio, functional groups, crystallinity, surface topography, and mechanical properties. Humidity was discovered to have the greatest effect on the ageing of PLA, followed by light and temperature. The interactions between temperature and light, as well as humidity and sunlight, significantly impact the aging of PLA. XPS analysis revealed PLA underwent aging due to the cleavage of the ester bond (O-C=O), resulting in the addition of C=O and C-O. The aging process of PLA was characterized by alterations in surface morphology and augmentation in crystallinity, resulting in a decline in both tensile strength and elongation. These findings might offer insights into the aging behavior of degradable plastics under diverse environmental conditions.


Asunto(s)
Ésteres , Plásticos , Poliésteres
8.
Environ Monit Assess ; 196(5): 445, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38607460

RESUMEN

Periphyton is a complex community composed of diverse prokaryotes and eukaryotes; understanding the characteristics of microbial communities within periphyton becomes crucial for biogeochemical cycles and energy dynamics of aquatic ecosystems. To further elucidate the community characteristics of periphyton across varied aquatic habitats, including unpolluted ecologically restored lakes, aquaculture ponds, and areas adjacent to domestic and industrial wastewater treatment plant outfalls, we explored the composition and diversity of prokaryotic and eukaryotic communities in periphyton by employing Illumina MiSeq sequencing. Our findings indicated that the prokaryotic communities were predominantly composed of Proteobacteria (40.92%), Bacteroidota (21.01%), and Cyanobacteria (10.12%), whereas the eukaryotic communities were primarily characterized by the dominance of Bacillariophyta (24.09%), Chlorophyta (20.83%), and Annelida (15.31%). Notably, Flavobacterium emerged as a widely distributed genus among the prokaryotic community. Unclassified_Tobrilidae exhibited higher abundance in unpolluted ecologically restored lakes. Chaetogaster and Nais were enriched in aquaculture ponds and domestic wastewater treatment plant outfall area, respectively, while Surirella and Gomphonema dominated industrial sewage treatment plant outfall area. The alpha diversity of eukaryotes was higher in unpolluted ecologically restored lakes. pH and nitrogen content ( NO 2 - - N , NO 3 - - N , and TN) significantly explained the variations for prokaryotic and eukaryotic community structures, respectively. Eukaryotic communities exhibited a more pronounced response to habitat variations compared to prokaryotic communities. Moreover, the association networks revealed an intensive positive correlation between dominant Bacillariophyta and Bacteroidota. This study provided useful data for identifying keystone species and understanding their ecological functions.


Asunto(s)
Diatomeas , Microbiota , Oligoquetos , Perifiton , Animales , Monitoreo del Ambiente , Acuicultura , Bacteroidetes
9.
Biol Reprod ; 109(5): 720-735, 2023 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-37552055

RESUMEN

Trophoblast plays a crucial role in gestation maintenance and embryo implantation, partly due to the synthesis of progesterone. It has been demonstrated that hypoxia regulates invasion, proliferation, and differentiation of trophoblast cells. Additionally, human trophoblasts display rhythmic expression of circadian clock genes. However, it remains unclear if the circadian clock system is present in goat trophoblast cells (GTCs), and its involvement in hypoxia regulation of steroid hormone synthesis remains elusive. In this study, immunofluorescence staining revealed that both BMAL1 and NR1D1 (two circadian clock components) were highly expressed in GTCs. Quantitative real-time PCR analysis showed that several circadian clock genes were rhythmically expressed in forskolin-synchronized GTCs. To mimic hypoxia, GTCs were treated with hypoxia-inducing reagents (CoCl2 or DMOG). Quantitative real-time PCR results demonstrated that hypoxia perturbed the mRNA expression of circadian clock genes and StAR. Notably, the increased expression of NR1D1 and the reduction of StAR expression in hypoxic GTCs were also detected by western blotting. In addition, progesterone secretion exhibited a notable decline in hypoxic GTCs. SR9009, an NR1D1 agonist, significantly decreased StAR expression at both the mRNA and protein levels and markedly inhibited progesterone secretion in GTCs. Moreover, SR8278, an NR1D1 antagonist, partially reversed the inhibitory effect of CoCl2 on mRNA and protein expression levels of StAR and progesterone synthesis in GTCs. Our results demonstrate that hypoxia reduces StAR expression via the activation of NR1D1 signaling in GTCs, thus inhibiting progesterone synthesis. These findings provide new insights into the NR1D1 regulation of progesterone synthesis in GTCs under hypoxic conditions.


Asunto(s)
Progesterona , Trofoblastos , Animales , Humanos , Trofoblastos/metabolismo , Cabras/genética , Hipoxia , ARN Mensajero , Cobalto , Miembro 1 del Grupo D de la Subfamilia 1 de Receptores Nucleares/genética , Miembro 1 del Grupo D de la Subfamilia 1 de Receptores Nucleares/metabolismo
10.
Eur J Nucl Med Mol Imaging ; 50(7): 1919-1928, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36813979

RESUMEN

PURPOSE: To assess the efficiency of [68 Ga]Ga-DOTA-FAPI-04 in diagnosing periprosthetic hip joint infection and establish a diagnostic standard of clinical significance based on uptake pattern. METHODS: [68 Ga]Ga-DOTA-FAPI-04 PET/CT was performed in patients with symptomatic hip arthroplasty from December 2019 to July 2022. The reference standard was based on the 2018 Evidence-Based and Validation Criteria. Two diagnostic criteria, SUVmax and uptake pattern, were used to diagnose PJI. Meanwhile, original data were imported into IKT-snap to draw the view of interest, A.K. was used to extract features of clinical cases, and unsupervised clustering analysis was applied according to the groups. RESULTS: A total of 103 patients were included, 28 of whom had PJI. The area under the curve of SUVmax was 0.898, which was better than that of all of the serological tests. The cutoff value of SUVmax was 7.53, and the sensitivity and specificity were 100 and 72%, respectively. The sensitivity, specificity and accuracy of the uptake pattern were 100, 93.1 and 95%, respectively. In radiomics analysis, the features of PJI were significantly different from those of aseptic failure. CONCLUSION: The efficiency of [68 Ga]Ga-DOTA-FAPI-04 PET/CT in diagnosing PJI showed promising results, and the diagnostic criteria of the uptake pattern were more clinically instructive. Radiomics also showed certain application prospects in the field of PJI. TRIAL REGISTRATION NUMBER: Trial registration: ChiCTR2000041204. Registered 24 September 2019.


Asunto(s)
Artritis Infecciosa , Tomografía Computarizada por Tomografía de Emisión de Positrones , Humanos , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Artritis Infecciosa/diagnóstico , Artritis Infecciosa/cirugía , Articulación de la Cadera , Radioisótopos de Galio , Fluorodesoxiglucosa F18
11.
Entropy (Basel) ; 25(11)2023 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-37998212

RESUMEN

In George Wald's Nobel Prize acceptance speech for "discoveries concerning the primary physiological and chemical visual processes in the eye", he noted that events after the activation of rhodopsin are too slow to explain visual reception. Photoreceptor membrane phosphoglycerides contain near-saturation amounts of the omega-3 fatty acid docosahexaenoic acid (DHA). The visual response to a photon is a retinal cis-trans isomerization. The trans-state is lower in energy; hence, a quantum of energy is released equivalent to the sum of the photon and cis-trans difference. We hypothesize that DHA traps this energy, and the resulting hyperpolarization extracts the energized electron, which depolarizes the membrane and carries a function of the photon's energy (wavelength) to the brain. There, it contributes to the creation of the vivid images of our world that we see in our consciousness. This proposed revision to the visual process provides an explanation for these previously unresolved issues around the speed of information transfer and the purity of conservation of a photon's wavelength and supports observations of the unique and indispensable role of DHA in the visual process.

12.
Small ; 18(13): e2106148, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35128785

RESUMEN

By virtue of the unprecedented ability of manipulating the optical parameters, metasurfaces open up a new avenue for realizing ultra-compact image displays, e.g., nanoprinting on the surface and holographic displaying in the far-field. The multifold integration of these two functions into a single metasurface can undoubtedly expand the functionality and increase the information capacity. In this study, a minimalist tri-channel metasurface is proposed and experimentally demonstrated with multifold integration of printed and holographic displaying, which can generate two N-bit grayscale images and a four-step holographic image simultaneously. Benefiting from exploiting the degeneracy of energy allocation and the degeneracy of nanostructure orientations, the functionalities of nanoprinting and holography are combined without the need of a large amount of nanostructures with varied dimensions, which would facilitate both the metasurface design and fabrication. The proposed scheme provides a new idea in enhancing the functionality and capacity of metasurfaces without complicating their design, which has promising prospects for applications in ultra-compact image displays, high-density optical storage, optical anti-counterfeiting and many other related fields.

13.
Mol Psychiatry ; 26(7): 2912-2928, 2021 07.
Artículo en Inglés | MEDLINE | ID: mdl-33057171

RESUMEN

The ventral pallidum (VP) regulates motivation, drug addiction, and several behaviors that rely on heightened arousal. However, the role and underlying neural circuits of the VP in the control of wakefulness remain poorly understood. In the present study, we sought to elucidate the specific role of VP GABAergic neurons in controlling sleep-wake behaviors in mice. Fiber photometry revealed that the population activity of VP GABAergic neurons was increased during physiological transitions from non-rapid eye movement (non-REM, NREM) sleep to either wakefulness or REM sleep. Moreover, chemogenetic and optogenetic manipulations were leveraged to investigate a potential causal role of VP GABAergic neurons in initiating and/or maintaining arousal. In vivo optogenetic stimulation of VP GABAergic neurons innervating the ventral tegmental area (VTA) strongly promoted arousal via disinhibition of VTA dopaminergic neurons. Functional in vitro mapping revealed that VP GABAergic neurons, in principle, inhibited VTA GABAergic neurons but also inhibited VTA dopaminergic neurons. In addition, optogenetic stimulation of terminals of VP GABAergic neurons revealed that they promoted arousal by innervating the lateral hypothalamus, but not the mediodorsal thalamus or lateral habenula. The increased wakefulness chemogenetically evoked by VP GABAergic neuronal activation was completely abolished by pretreatment with dopaminergic D1 and D2/D3 receptor antagonists. Furthermore, activation of VP GABAergic neurons increased exploration time in both the open-field and light-dark box tests but did not modulate depression-like behaviors or food intake. Finally, chemogenetic inhibition of VP GABAergic neurons decreased arousal. Taken together, our findings indicate that VP GABAergic neurons are essential for arousal related to motivation.


Asunto(s)
Prosencéfalo Basal , Vigilia , Animales , Neuronas GABAérgicas , Ratones , Motivación , Área Tegmental Ventral
14.
Nanotechnology ; 33(22)2022 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-35148522

RESUMEN

Long-wave infrared imaging systems are widely used in the field of environmental monitoring and imaging guidance. As the core components, the long-wave infrared lenses suffer the conditions of less available materials, difficult processing, large volume and mass. Metalens composed of sub-wavelength structures is one of the most potential candidates to achieve a lightweight and planar optical imaging systems. Meanwhile, it is essential to obtain large-aperture infrared lenses with high power and high resolution. However, it is difficult to use the finite-difference time-domain method to simulate a large-aperture metalens with the diameter of 201 mm due to the large amount of computational memory and computational time required. Here, to solve the mentioned problem, we firstly propose a simulation method for designing a large-aperture metalens, which combines the finite-difference time-domain algorithm and diffraction integration. The finite-difference time-domain algorithm is used to simulate the meta-atom's transmitted complex amplitude and the one-dimensional simplification of the diffraction integral is to calculate the focused field distributions of the designed metalens. Furthermore, the meta-atom spatial multiplexing is applied to design the all-silicon metalenses with the aperture of 201 mm to realize dual-wavelength (10 and 11µm) achromatic focusing, super anomalous dispersion focusing and super normal dispersion focusing. The designed metalenses are numerically confirmed, which reveal the feasibility of all-silicon sub-wavelength structures to accomplish the multiwavelength dispersion control. The designed all-silicon metalenses have the advantage of lightweight and compact. The proposed method is effective for the development of large-aperture imaging systems in the long-wave infrared.

15.
Environ Sci Technol ; 56(12): 7618-7628, 2022 06 21.
Artículo en Inglés | MEDLINE | ID: mdl-35608856

RESUMEN

Hydrogen peroxide (H2O2) and hydroxyl radical (OH) are important oxidants in the atmospheric aqueous phase such as cloud droplets and deliquescent aerosol particles, playing a significant role in the chemical transformation of organic and inorganic pollutants in the atmosphere. Atmospheric aqueous-phase chemistry has been considered to be a source of H2O2 and OH. However, our understanding of the mechanisms of their formation in atmospheric waters is still incomplete. Here, we show that the aqueous-phase reaction of dissolved ozone (O3) with substituted phenols such as m-cresol represents an important source of H2O2 and OH exhibiting pH-dependent yields. Intriguingly, the formation of H2O2 through the ring-opening mechanism is strongly promoted under lower pH conditions (pH 2.5-3.5), while higher pH favors the ring-retaining pathways yielding OH. The rate constant of the reaction of O3 with m-cresol increases with increasing pH. The reaction products formed during the ozonolysis of m-cresol are analyzed by an Orbitrap mass spectrometer, and reaction pathways are suggested based on the identified product compounds. This study indicates that aqueous-phase ozonolysis of phenolic compounds might be an alternative source of H2O2 and OH in the cloud, rain, and liquid water of aerosol particles; thus, it should be considered in future model studies.


Asunto(s)
Peróxido de Hidrógeno , Ozono , Aerosoles/química , Atmósfera/química , Cresoles , Concentración de Iones de Hidrógeno , Radical Hidroxilo/química , Oxidación-Reducción , Ozono/química , Agua
16.
Environ Sci Technol ; 56(9): 5398-5408, 2022 May 03.
Artículo en Inglés | MEDLINE | ID: mdl-35420794

RESUMEN

Methoxyphenols represent important pollutants that can participate in the formation of secondary organic aerosols (SOAs) through chemical reactions with atmospheric oxidants. In this study, we determine the influence of ionic strength, pH, and temperature on the heterogeneous reaction of NO2 with an aqueous film consisting of acetosyringone (ACS), as a proxy for methoxyphenols. The uptake coefficient of NO2 (50 ppb) on ACS (1 × 10-5 mol L-1) is γ = (9.3 ± 0.09) × 10-8 at pH 5, and increases by one order of magnitude to γ = (8.6 ± 0.5) × 10-7 at pH 11. The lifetime of ACS due to its reaction with NO2 is largely affected by the presence of nitrate ions and sulfate ions encountered in aqueous aerosols. The analysis performed by membrane inlet single-photon ionization-time-of-flight mass spectrometry (MI-SPI-TOFMS) reveals an increase in the number of product compounds and a change of their chemical composition upon addition of nitrate ions and sulfate ions to the aqueous thin layer consisting of ACS. These outcomes indicate that inorganic ions can play an important role during the heterogeneous oxidation processes in aqueous aerosol particles.

17.
Environ Sci Technol ; 56(22): 15377-15388, 2022 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-36279129

RESUMEN

The primarily emitted compounds by human presence, e.g., skin and volatile organic compounds (VOCs) in breath, can react with typical indoor air oxidants, ozone (O3), and hydroxyl radicals (OH), leading to secondary organic compounds. Nevertheless, our understanding about the formation processes of the compounds through reactions of indoor air oxidants with primary emitted pollutants is still incomplete. In this study we performed real-time measurements of nitrous acid (HONO), nitrogen oxides (NOx = NO + NO2), O3, and VOCs to investigate the contribution of human presence and human activity, e.g., mopping the floor, to secondary organic compounds. During human occupancy a significant increase was observed of 1-butene, isoprene, and d-limonene exhaled by the four adults in the room and an increase of methyl vinyl ketone/methacrolein, methylglyoxal, and 3-methylfuran, formed as secondary compounds through reactions of OH radicals with isoprene. Intriguingly, the level of some compounds (e.g., m/z 126, 6-methyl-5-hepten-2-one, m/z 152, dihydrocarvone, and m/z 194, geranyl acetone) formed through reactions of O3 with the primary compounds was higher in the presence of four adults than during the period of mopping the floor with commercial detergent. These results indicate that human presence can additionally degrade the indoor air quality.


Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire Interior , Contaminantes Ambientales , Ozono , Compuestos Orgánicos Volátiles , Humanos , Contaminación del Aire Interior/análisis , Ozono/análisis , Contaminantes Atmosféricos/análisis , Oxidantes
18.
BMC Musculoskelet Disord ; 23(1): 592, 2022 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-35725436

RESUMEN

PURPOSE: We built a joint replacement loosening model based on the original rabbit model of infection and evaluated the performance characteristics of 18F-FDG and 68 Ga-FAPI in evaluating infection and loosening. METHODS: After surgery, the rabbits were divided into four groups, with six individuals in the control group and 10 each in the aseptic loosening, S. aureus and S. epidermidis groups. PET/CT and serological examination were performed three times at two-week intervals. After the rabbits were euthanized, micro-CT, tissue pathology, pullout tests and scanning electron microscopy (SEM) were performed. RESULTS: The pullout test and SEM showed the feasibility of the aseptic loosening model. 18F-FDG showed similar performance in the control and loosening groups. The SUVmax of the S. aureus group was consistently higher than that of the S. epidermidis group. As for 68 Ga-FAPI, the SUVmax of the control group was lowest in the second week and gradually increased over subsequent weeks. The SUVmax of the loosening group began to exceed that of the control group after the second week. The SUVmax of the S. aureus group in the second week was the lowest among the four groups and increased as the number of weeks increased. The pathology results showed concordance with the performance of PET/CT. Linear regressions between SUVmax and serology showed that 18F-FDG was positively correlated with CRP and IL-6, while 68 Ga-FAPI revealed negative correlations with CRP and IL-6 in the second week and positive correlations in the sixth week. In addition, the SUVmax and MT(target)V of both 18F-FDG and 68 Ga-FAPI were negatively correlated with bone volume/trabecular volume (TV) and bone surface area/TV. CONCLUSION: In this longitudinal observation, 68 Ga-FAPI showed greater sensitivity than 18F-FDG in detecting diseases, and 68 Ga-FAPI had no intestinal or muscular uptake. The MT(target)V of 68 Ga-FAPI was larger than that of 18F-FDG, which meant that 68 Ga-FAPI had the potential to define the scope of lesions more accurately. Finally, the SUVmax of 68 Ga-FAPI could not differentiate between loosening and infection; further study of the diagnostic criteria is warranted.


Asunto(s)
Artritis Infecciosa , Infecciones Relacionadas con Prótesis , Animales , Fluorodesoxiglucosa F18 , Interleucina-6 , Tomografía Computarizada por Tomografía de Emisión de Positrones/métodos , Infecciones Relacionadas con Prótesis/diagnóstico por imagen , Infecciones Relacionadas con Prótesis/etiología , Conejos , Staphylococcus aureus
19.
Nano Lett ; 21(14): 5931-5937, 2021 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-34176272

RESUMEN

Nanofabrication schemes usually suffer challenges in direct growth on complex nanostructured substrates. We provide a new technology that allows for the convenient, selective growth of complex nanostructures directly on three-dimensional (3D) homogeneous semiconductor substrates. The nature of the selectivity is derived from surface states modulated electrochemical deposition. Metals, metal oxides, and compound semiconductor structures can be prepared with high fidelity over a wide scale range from tens of nanometers to hundreds of microns. The utility of the process for photoelectrochemical applications is demonstrated by selectively decorating the sidewalls and tips of silicon microwires with cuprous oxide and cobalt oxides catalysts, respectively. Our findings indicate a new selective fabrication concept applied for homogeneous 3D semiconductor substrates, which is of high promise in community of photoelectronics, photoelectrochemistry, photonics, microelectronics, etc.

20.
Int J Mol Sci ; 23(9)2022 Apr 21.
Artículo en Inglés | MEDLINE | ID: mdl-35562990

RESUMEN

Sleep and wakefulness are basic behavioral states that require coordination between several brain regions, and they involve multiple neurochemical systems, including neuropeptides. Neuropeptides are a group of peptides produced by neurons and neuroendocrine cells of the central nervous system. Like traditional neurotransmitters, neuropeptides can bind to specific surface receptors and subsequently regulate neuronal activities. For example, orexin is a crucial component for the maintenance of wakefulness and the suppression of rapid eye movement (REM) sleep. In addition to orexin, melanin-concentrating hormone, and galanin may promote REM sleep. These results suggest that neuropeptides play an important role in sleep-wake regulation. These neuropeptides can be divided into three categories according to their effects on sleep-wake behaviors in rodents and humans. (i) Galanin, melanin-concentrating hormone, and vasoactive intestinal polypeptide are sleep-promoting peptides. It is also noticeable that vasoactive intestinal polypeptide particularly increases REM sleep. (ii) Orexin and neuropeptide S have been shown to induce wakefulness. (iii) Neuropeptide Y and substance P may have a bidirectional function as they can produce both arousal and sleep-inducing effects. This review will introduce the distribution of various neuropeptides in the brain and summarize the roles of different neuropeptides in sleep-wake regulation. We aim to lay the foundation for future studies to uncover the mechanisms that underlie the initiation, maintenance, and end of sleep-wake states.


Asunto(s)
Galanina , Neuropéptidos , Galanina/farmacología , Péptidos y Proteínas de Señalización Intracelular/farmacología , Neuropéptidos/metabolismo , Orexinas/farmacología , Sueño/fisiología , Péptido Intestinal Vasoactivo/farmacología
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