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1.
Plant Cell ; 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38723165

RESUMO

Arabidopsis (Arabidopsis thaliana) plants can produce photosynthetic tissue with active chloroplasts at temperatures as low as 4°C, and this process depends on the presence of the nuclear-encoded, chloroplast-localized RNA-binding protein CP29A. In this study, we demonstrate that CP29A undergoes phase separation in vitro and in vivo in a temperature-dependent manner, which is mediated by a prion-like domain (PLD) located between the two RNA recognition motif (RRM) domains of CP29A. The resulting droplets display liquid-like properties and are found near chloroplast nucleoids. The PLD is required to support chloroplast RNA splicing and translation in cold-treated tissue. Together, our findings suggest that plant chloroplast gene expression is compartmentalized by inducible condensation of CP29A at low temperatures, a mechanism that could play a crucial role in plant cold resistance.

2.
Nanotechnology ; 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38744249

RESUMO

Long term stability, high responsivity, and fast response speed are essential for the commercialization of graphene photodetectors (GPDs). In this work, a parylene/graphene UV photodetector with long term stability, ultrahigh responsivity and fast response speed, is demonstrated. Parylene as a stable physical and chemical insulating layer reduces the environmental sensitivity of graphene, and enhances the performances of GPDs. In addition, utilizing bilayer electrodes reduces the buckling and damage of graphene after transferring. Parylene/graphene UV photodetector exhibits an ultrahigh responsivity of 5.82×10^5 A/W under 325 nm light irradiation at 1 V bias. Additionally, it shows a fast response speed of 17 µs, and a long term stability at 405 nm wavelength which is absent in the device without parylene. Parylene/graphene UV photodetector possesses superior performances. This paves the way to realize the commercial application of high-performance graphene hybrid photodetectors, and provides a practical method for maintaining the long term stability of two dimensional (2D) materials. .

3.
Opt Lett ; 49(10): 2757-2760, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38748154

RESUMO

Optical camera communication (OCC) has attracted increased attention for its inherent security advantage. However, there still exists the risk of eavesdropping on the broadcasting channel of OCC. To achieve confidential communication, we propose the confidentiality-interference dual light-emitting diode (LED) communication (CIDLC) scheme at the transmitter (TX) and elimination of interference (EI) scheme at the receiver (RX). Meanwhile, interference signals refer to the bit shift of confidential signals. Further, we propose the two-dimensional pilot-aided channel estimation (2D-PACE) scheme to enhance the reliability of multiple-input multiple-output (MIMO) OCC. Experiment results validate the effectiveness of our schemes, which guarantee confidentiality while performing well at a 2 m non-line-of-sight (NLOS) distance. Finally, the communication-illumination integration OCC is constructed via the energy equalization coding (EEC) scheme.

4.
Materials (Basel) ; 17(9)2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38730971

RESUMO

The manufacturing process for wrought Ti alloys with the hexagonal close-packed (HCP) structure introduces a complicated microstructure with abundant intra- and inter-grain boundaries, which greatly influence performance. In the hexagonal close-packed (HCP) structure, two types of grain boundaries are commonly observed between grains with ~90° misorientation: the basal/prismatic boundary (BPB) and the coherent twin boundary (CTB). The mechanical response of the BPB and CTB under external loading was studied through molecular dynamic simulations of HCP-Ti. The results revealed that CTB undergoes transformation into BPB through the accumulation of twin boundary (TB) steps and subsequent emission of Shockley partial dislocations. When the total mismatch vector is close to the Burgers vector of a Shockley partial dislocation, BPB emits partial dislocations and further grows along the stacking faults. When a pair of CTBs are close to each other, severe boundary distortion occurs, facilitating the emission and absorption of partial dislocations, which further assists the CTB-BPB transformation. The present results thus help to explain the frequent observation of coexisting CTB and BPB in HCP alloys and further contribute to the understanding of their microstructure and property regulation.

5.
bioRxiv ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38765966

RESUMO

Microenvironment niches determine cellular fates of metastatic cancer cells. However, robust and unbiased approaches to identify niche components and their molecular profiles are lacking. We established Sortase A-Based Microenvironment Niche Tagging (SAMENT), which selectively labels cells encountered by cancer cells during metastatic colonization. SAMENT was applied to multiple cancer models colonizing the same organ and the same cancer to different organs. Common metastatic niche features include macrophage enrichment and T cell depletion. Macrophage niches are phenotypically diverse between different organs. In bone, macrophages express the estrogen receptor alpha (ERα) and exhibit active ERα signaling in male and female hosts. Conditional knockout of Esr1 in macrophages significantly retarded bone colonization by allowing T cell infiltration. ERα expression was also discovered in human bone metastases of both genders. Collectively, we identified a unique population of ERα+ macrophages in the metastatic niche and functionally tied ERα signaling in macrophages to T cell exclusion during metastatic colonization. HIGHLIGHTS: SAMENT is a robust metastatic niche-labeling approach amenable to single-cell omics.Metastatic niches are typically enriched with macrophages and depleted of T cells.Direct interaction with cancer cells induces ERα expression in niche macrophages. Knockout of Esr1 in macrophages allows T cell infiltration and retards bone colonization.

6.
Int J Mol Sci ; 25(9)2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38732273

RESUMO

Drought and salinity stress reduce root hydraulic conductivity of plant seedlings, and melatonin application positively mitigates stress-induced damage. However, the underlying effect of melatonin priming on root hydraulic conductivity of seedlings under drought-salinity combined remains greatly unclear. In the current report, we investigated the influence of seeds of three wheat lines' 12 h priming with 100 µM of melatonin on root hydraulic conductivity (Lpr) and relevant physiological indicators of seedlings under PEG, NaCl, and PEG + NaCl combined stress. A previous study found that the combined PEG and NaCl stress remarkably reduced the Lpr of three wheat varieties, and its value could not be detected. Melatonin priming mitigated the adverse effects of combined PEG + NaCl stress on Lpr of H4399, Y1212, and X19 to 0.0071 mL·h-1·MPa-1, 0.2477 mL·h-1·MPa-1, and 0.4444 mL·h-1·MPa-1, respectively, by modulating translation levels of aquaporin genes and contributed root elongation and seedlings growth. The root length of H4399, Y1212, and X19 was increased by 129.07%, 141.64%, and 497.58%, respectively, after seeds pre-treatment with melatonin under PEG + NaCl combined stress. Melatonin -priming appreciably regulated antioxidant enzyme activities, reduced accumulation of osmotic regulators, decreased levels of malondialdehyde (MDA), and increased K+ content in stems and root of H4399, Y1212, and X19 under PEG + NaCl stress. The path investigation displayed that seeds primed with melatonin altered the modification of the path relationship between Lpr and leaf area under stress. The present study suggested that melatonin priming was a strategy as regards the enhancement of root hydraulic conductivity under PEG, NaCl, and PEG + NaCl stress, which efficiently enhanced wheat resistant to drought-salinity stress.


Assuntos
Secas , Melatonina , Raízes de Plantas , Salinidade , Plântula , Sementes , Triticum , Melatonina/farmacologia , Triticum/efeitos dos fármacos , Triticum/genética , Triticum/fisiologia , Triticum/crescimento & desenvolvimento , Triticum/metabolismo , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Sementes/efeitos dos fármacos , Plântula/efeitos dos fármacos , Plântula/metabolismo , Plântula/genética , Estresse Fisiológico/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Estresse Salino , Cloreto de Sódio/farmacologia , Antioxidantes/metabolismo , Água/metabolismo
7.
Cancer Med ; 13(9): e7221, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38733179

RESUMO

BACKGROUND: Cervical cancer is one of the most common gynecological cancers. Accumulated evidence shows that long non-coding RNAs (lncRNAs) play essential roles in cervical cancer occurrence and progression, but their specific functions and mechanisms remain to be further explored. METHODS: The RT-qPCR assay was used to detect the expression of NEAT1 in cervical cancer tissues and cell lines. CCK-8, colony formation, flow cytometry, western blotting, and Transwell assays were used to evaluate the impact of NEAT1 on the malignant behavior of cervical cancer cells. Glucose consumption, lactate production, ATP levels, ROS levels, MMP levels, and the mRNA expressions of glycolysis-related genes and tricarboxylic acid cycle-related genes were detected to analyze the effect of NEAT1 on metabolism reprograming in cervical cancer cells. The expressions of PDK1, ß-catenin and downstream molecules of the WNT/ß-catenin signaling pathway in cervical cancer cells and tissues were detected by western blotting, RT-qPCR, immunofluorescence and immunohistochemistry assays. RESULTS: This study investigated the role and possible molecular mechanism of lncRNA nuclear paraspeckle assembly transcript 1 (NEAT1) in cervical cancer. Our results showed that NEAT1 was highly expressed in cervical cancer tissues and cell lines. Downregulation of NEAT1 inhibited the proliferation, migration, invasion and glycolysis of cervical cancer cells, while overexpression of NEAT1 led to the opposite effects. Mechanistically, NEAT1 upregulated pyruvate dehydrogenase kinase (PDK1) through the WNT/ß-catenin signaling pathway, which enhanced glycolysis and then facilitated cervical cancer metastasis. Furthermore, NEAT1 maintained the protein stability of ß-catenin but did not affect its mRNA level. We also excluded the direct binding of NEAT1 to the ß-catenin protein via RNA pull-down assay. The suppressive impact of NEAT1 knockdown on cell proliferation, invasion, and migration was rescued by ß-catenin overexpression. The WNT inhibitor iCRT3 attenuated the carcinogenic effect induced by NEAT1 overexpression. CONCLUSION: In summary, these findings indicated that NEAT1 may contribute to the progression of cervical cancer by activating the WNT/ß-catenin/PDK1 signaling axis.


Assuntos
Proliferação de Células , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Piruvato Desidrogenase Quinase de Transferência de Acetil , RNA Longo não Codificante , Neoplasias do Colo do Útero , Via de Sinalização Wnt , Humanos , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/patologia , Neoplasias do Colo do Útero/metabolismo , Feminino , Piruvato Desidrogenase Quinase de Transferência de Acetil/metabolismo , Piruvato Desidrogenase Quinase de Transferência de Acetil/genética , Linhagem Celular Tumoral , beta Catenina/metabolismo , beta Catenina/genética , Glicólise , Movimento Celular
8.
Org Lett ; 2024 May 12.
Artigo em Inglês | MEDLINE | ID: mdl-38735050

RESUMO

An enantioselective Pd-catalyzed intramolecular desymmetrizing cycloisomerization of N-(cyclopent-3-en-1-yl)propiolamides has been developed by employing a new chiral phosphoramidite ligand. A series of structurally unique bridged azabicycles are achieved in moderate to excellent yields with good E/Z selectivity and high enantioselectivity. Synthetic transformations are conducted to demonstrate the practical utility of this reaction.

9.
J Biol Chem ; : 107361, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38735473

RESUMO

Nucleoside analogue drugs are pervasively used as antiviral and chemotherapy agents. Cytarabine and gemcitabine are anti-cancer nucleoside analogue drugs that contain C2´ modifications on the sugar ring. Despite carrying all the required functional groups for DNA synthesis, these two compounds inhibit DNA extension once incorporated into DNA. It remains unclear how the C2´ modifications on cytarabine and gemcitabine affect the polymerase active site during substrate binding and DNA extension. Using steady-state kinetics, static and time-resolved X-ray crystallography with DNA polymerase η (Pol η) as a model system, we showed that the sugar ring C2´ chemical groups on cytarabine and gemcitabine snugly fit within the Pol η active site without occluding the steric gate. During DNA extension, Pol η can extend past gemcitabine but with much lower efficiency past cytarabine. Pol η crystal structures show that the -OH modification in the ß direction on cytarabine locks the sugar ring in an unfavorable C2´-endo geometry for product formation. On the other hand, the addition of fluorine atoms on gemcitabine alters the proper conformational transition of the sugar ring for DNA synthesis. Our study illustrates mechanistic insights into chemotherapeutic drug inhibition and resistance and provides guidance for future optimization of nucleoside analogue drugs.

10.
Biomark Res ; 12(1): 48, 2024 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-38730450

RESUMO

BACKGROUND: Tumors exhibit metabolic heterogeneity, influencing cancer progression. However, understanding metabolic diversity in retinoblastoma (RB), the primary intraocular malignancy in children, remains limited. METHODS: The metabolic landscape of RB was constructed based on single-cell transcriptomic sequencing from 11 RB and 5 retina samples. Various analyses were conducted, including assessing overall metabolic activity, metabolic heterogeneity, and the correlation between hypoxia and metabolic pathways. Additionally, the expression pattern of the monocarboxylate transporter (MCT) family in different cell clusters was examined. Validation assays of MCT1 expression and function in RB cell lines were performed. The therapeutic potential of targeting MCT1 was evaluated using an orthotopic xenograft model. A cohort of 47 RB patients was analyzed to evaluate the relationship between MCT1 expression and tumor invasion. RESULTS: Distinct metabolic patterns in RB cells, notably increased glycolysis, were identified. This metabolic heterogeneity correlated closely with hypoxia. MCT1 emerged as the primary monocarboxylate transporter in RB cells. Disrupting MCT1 altered cell viability and energy metabolism. In vivo studies using the MCT1 inhibitor AZD3965 effectively suppressed RB tumor growth. Additionally, a correlation between MCT1 expression and optic nerve invasion in RB samples suggested prognostic implications. CONCLUSIONS: This study enhances our understanding of RB metabolic characteristics at the single-cell level, highlighting the significance of MCT1 in RB pathogenesis. Targeting MCT1 holds promise as a therapeutic strategy for combating RB, with potential prognostic implications.

11.
Infect Drug Resist ; 17: 1911-1918, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38766680

RESUMO

The liver receives blood from both the hepatic artery and portal vein. Hepatic infarction is rare in clinical practice as both the hepatic artery and portal vein can supply blood to the liver. Here, we reported a case of a 75-year-old man who underwent radical laparoscopic surgery for rectal cancer and subsequently developed hepatic infarction. The patient experienced severe infection, as well as circulatory and respiratory failure on the third day after surgery. The patient presented with high fever, chest tightness, shortness of breath, decreased blood oxygen saturation and blood pressure. The leukocyte count decreased from 8.10 × 10^9/L to 1.75 × 10^9/L. Procalcitonin (PCT) levels increased from 1.02 ng/mL to 67.14 ng/mL, and eventually reaching levels over 200 ng/mL. Enhanced abdominal computed tomography (CT) confirmed the presence of hepatic infarction, but no thrombosis was observed in the hepatic artery or portal vein. Metagenomic next-generation sequencing (mNGS) identified hypervirulent Klebsiella pneumoniae (hvKp) in the patient's blood and ascites, one day earlier than the detection results using traditional culture methods. The patient was diagnosed with hepatic infarction combined with septic shock caused by hvKp. This case emphasizes that in the high-risk group of thrombosis, infection can trigger exacerbated hepatic infarction events, particularly in cases after surgical procedures. For severely ill patients with infectious diseases who are admitted to the ICU with worsening symptoms, it is important to collect appropriate samples and send them for pathogen detection using mNGS in a timely manner. This may aid in early intervention and improve clinical outcomes.

12.
Indian J Ophthalmol ; 2024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38767559

RESUMO

PURPOSE: To evaluate the effect of anterior-segment structure on vault and position after implantable collamer lens (ICL) implantation using ultrasound biomicroscopy. METHODS: The retrospective case-control study included insufficient vault eyes (<250 µm), ideal vault eyes (250-750 µm), and excessive vault eyes (>750 µm). The preoperative biometric parameters of the anterior-segment structure and basic data between the three groups were analyzed using one-way analysis of variance. RESULTS: There were significant differences ( P < 0.05) between the three groups in maximum ciliary body thickness (CBT max ), iris-zonule distance (IZD), and trabecular-ciliary angle (TCA). The vault gradually decreased as CBT max decreased and TCA increased. In the pairwise comparison, the CBT max comparison between the insufficient vault (<250 µm) group and the excessive vault (>750 µm) group was statistically significant ( P = 0.024, 95% CI: -0.17-0.017 µm); the TCA comparison between the insufficient vault (<250 µm) group and the excessive vault (>750 µm) group was statistically significant ( P = 0.005, 95% CI: 1.78°-12.15°); The IZD comparison between the insufficient vault (<250 µm) group and the excessive vault (>750 µm) group was statistically significant ( P = 0.037, 95% CI: 0.0027-0.1119 µm). The analysis of 284 ICL haptics locations showed that there were 16.67%, 32.69%, and 70.83% haptics located in the ciliary sulcus in three groups, respectively. CONCLUSION: The vault and ICL haptics position are related to anterior-segment structure. A thinner and posteriorly positioned ciliary body would increase the risk of low vault and fewer ICL haptics located in the ciliary sulcus after ICL implantation. This provides guidance for the selection of the ICL size and placement position before surgery.

13.
Int J Med Sci ; 21(6): 1037-1048, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38774758

RESUMO

Background: Inflammatory responses, apoptosis, and oxidative stress, are key factors that contribute to hepatic ischemia/reperfusion (I/R) injury, which may lead to the failure of liver surgeries, such as hepatectomy and liver transplantation. The N6-methyladenosine (m6A) modification has been implicated in multiple biological processes, and its specific role and mechanism in hepatic I/R injury require further investigation. Methods: Dot blotting analysis was used to profile m6A levels in liver tissues at different reperfusion time points in hepatic I/R mouse models. Hepatocyte-specific METTL3 knockdown (HKD) mice were used to determine the function of METTL3 during hepatic I/R. RNA sequencing and western blotting were performed to assess the potential signaling pathways involved with the deficiency of METTL3. Finally, AAV8-TBG-METTL3 was injected through the tail vein to further elucidate the role of METTL3 in hepatic I/R injury. Results: The m6A modification levels and the expression of METTL3 were upregulated in mouse livers during hepatic I/R injury. METTL3 deficiency led to an exacerbated inflammatory response and increased cell death during hepatic I/R, whereas overexpression of METTL3 reduced the extent of liver injury. Bioinformatic analysis revealed that the MAPK pathway was significantly enriched in the livers of METTL3-deficient mice. METTL3 protected the liver from I/R injury, possibly by inhibiting the phosphorylation of JNK and ERK, but not P38. Conclusions: METTL3 deficiency aggravates hepatic I/R injury in mice by activating the MAPK signaling pathway. METTL3 may be a potential therapeutic target in hepatic I/R injury.


Assuntos
Fígado , Sistema de Sinalização das MAP Quinases , Metiltransferases , Traumatismo por Reperfusão , Animais , Traumatismo por Reperfusão/genética , Traumatismo por Reperfusão/patologia , Camundongos , Metiltransferases/genética , Metiltransferases/metabolismo , Fígado/patologia , Fígado/metabolismo , Sistema de Sinalização das MAP Quinases/genética , Modelos Animais de Doenças , Masculino , Apoptose/genética , Camundongos Knockout , Humanos , Adenosina/metabolismo , Adenosina/análogos & derivados , Hepatócitos/metabolismo , Hepatócitos/patologia , Camundongos Endogâmicos C57BL
14.
Phys Chem Chem Phys ; 26(20): 14919-14929, 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38738775

RESUMO

We proposed a far-infrared tunable metamaterial absorber using vanadium dioxide (VO2) and graphene as controlling materials. The properties of the absorber are investigated theoretically using the finite-difference time-domain (FDTD) technique. It was found that when the Fermi energy level of graphene is fixed at zero, VO2 is in the insulated state, and the metasurface exhibits far-infrared broadband absorption performance, with absorptance exceeding 90% in the wavelength range of 12.6 µm to 23.2 µm. In addition, by elevating the Fermi energy level of graphene, the absorption bandwidth of the device is expanded continuously. When the VO2 is in the metallic state, the device can flexibly transform into a far-infrared narrowband absorber. The device also has the advantage of being insensitive to changes in polarization and incident angle. The origin of the absorption and the tuning principle of the device were analyzed and verified successfully by using an equivalent circuit model (ECM). Besides, we also studied the refraction index sensing characteristics of the absorber. Surprisingly, the absorber exhibits excellent sensing characteristics, and its sensitivity (S) reaches 14.108 µm per RIU and the figure of merit (FOM) is 6.13 per RIU.

15.
J Cell Mol Med ; 28(10): e18363, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38770891

RESUMO

The spleen is a vital organ for the immune system, while splenectomy may be necessary for various reasons. However, there is limited research on the impact of splenectomy on T cell function in peripheral lymph nodes as a compensatory mechanism in preventing infections. This study aimed to investigate the characteristics and function of CD8+ and CD4+ T cells in different peripheral lymph nodes during viral infection using a well-established splenectomy model. The results revealed that splenectomy caused an increase in CD8+GP33+ T cells in the mesenteric lymph nodes (MLN). Moreover, we demonstrated that splenectomy resulted in an increase of effector KLRG1+ T cells in the MLN. Additionally, the number of CD4+ cytotoxic T cells (CD4 CTLs) was also elevated in the peripheral lymph nodes of mice with splenectomy. Surprisingly, aged mice exhibited a stronger compensatory ability than adult mice, as evidenced by an increase in effector CD8+ T cells in all peripheral lymph nodes. These findings provide compelling evidence that T cells in MLN play a crucial role in protecting individuals with splenectomy against viral infections. The study offers new insights into understanding the changes in the immune system of individuals with splenectomy and highlights the potential compensatory mechanisms involved by T cells in peripheral lymph nodes.


Assuntos
Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , Linfonodos , Esplenectomia , Animais , Linfonodos/imunologia , Camundongos , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD4-Positivos/imunologia , Camundongos Endogâmicos C57BL , Baço/imunologia
16.
Aging (Albany NY) ; 162024 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-38771141

RESUMO

BACKGROUND: The purpose of this prospective study was to evaluate the association of systemic immune-inflammation index (SII) and systemic inflammation response index (SIRI), with PSCI in patients with acute ischemic stroke (AIS). METHODS: First-onset AIS patients were consecutively included from January 1, 2022 to March 1, 2023. The baseline information was collected at admission. Fasting blood was drawn the next morning. Cognitive function was assessed by the Montreal Cognitive Assessment (MoCA) 3 months after onset. Logistic regression analysis was performed to explore the correlation between SII, SIRI, and PSCI. Receiver operating characteristic (ROC) was conducted to evaluate the predictive ability of SII. RESULTS: 332 participants were recruited, and 193 developed PSCI. Compared with patients without PSCI, the patients with PSCI had higher SII (587.75 (337.42, 988.95) vs. 345.66 (248.44, 572.89), P<0.001) and SIRI (1.59 (0.95, 2.84) vs. 1.02 (0.63, 1.55), P=0.007). SII and SIRI negatively correlated with MoCA scores (both P<0.05). The multivariable logistic regression analysis indicated that SII was independently associated with PSCI (P<0.001), while SIRI was not. The optimal cutoff for SII to predict PSCI was 676.83×109/L. CONCLUSIONS: A higher level of SII upon admission was independently correlated to PSCI three months later in AIS patients.

17.
Sci Total Environ ; 933: 173227, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38750744

RESUMO

Pre-existing particles usually constitute the major fraction of atmospheric particles, except during some episodes in the presence of strong emissions and/or secondary generation of fresh particles. Previous case studies have investigated the growth of pre-existing particles and their potential environmental and climate impacts. However, there is limited knowledge about the statistical characteristics of these growth events and related effects. In this study, we examine pre-existing particle growth events using a large dataset (725 days from 2010 to 2018) collected at a coastal megacity in northern China. The occurrence frequency of pre-existing particle growth events was 12.4 % (90 out of 725 days). When these events were related to measured criteria air pollutants, no significant differences were found in PM2.5, SO2, NO2 and NO2 + O3 concentrations between periods with and without pre-existing particle growth events. These 90-day events can be further classified into two categories, i.e., Category 1, with 68 % of events representing the growth of pre-existing particles alone, and Category 2, with 32 % of events representing the simultaneous growth of pre-existing and newly formed particles. In Category 2, the growth rates of pre-existing particles and newly formed particles were close in 21 % of the cases, while pre-existing particles exhibited significantly larger growth rates in 69 % of the cases. Conversely, in 10 % of the cases, the growth rates of newly formed particles were larger. The different growth rate mechanisms were discussed in terms of the volatility of atmospheric condensation vapors. In addition, we present case studies on the impact of pre-existing particle growth on cloud condensation nuclei simultaneously measured, specifically considering the chemistry of condensation vapors and pre-existing particles.

18.
BMJ Open ; 14(5): e078126, 2024 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-38740506

RESUMO

OBJECTIVE: To examine the current prevalence and cost of paediatric off-label drug prescriptions in Gansu, China, and the potential influencing factors. DESIGN: The prevalence of off-label prescriptions in paediatrics was evaluated according to the National Medical Products Administration drug instructions in the China Pharmaceutical Reference (China Pharmaceutical Reference, MCDEX) database. The evidence of the prescription was determined by existing clinical practice guidelines and the Thomson Grade in the Micromedex 2021 compendium. We used logistic regression to investigate the characteristics that influence paediatric off-label drug use after single-factor regression analysis. SETTING: A multicentre cross-sectional study of outpatient paediatric prescriptions in 196 secondary and tertiary hospitals in Gansu Province, China, in March and September 2020. RESULTS: We retrieved 104 029 paediatric prescriptions, of which 39 480 (38.0%) contained off-label use. The most common diseases treated by off-label drugs were respiratory system diseases (n=15 831, 40.1%). A quarter of off-label prescriptions had adequate evidence basis (n=10 130, 25.6%). Unapproved indications were the most common type of off-label drug use (n=25 891, 65.6%). A total of 1177 different drugs were prescribed off-label, with multienzyme tablets being the most common drug (n=1790, 3.5%). The total cost of the prescribed off-label drugs was ¥106 116/day. Off-label prescriptions were less frequent in tertiary than in secondary hospitals. Topical preparations were more commonly prescribed off-label than other types of drugs. Senior-level clinicians prescribed drugs off-label more often than intermediate and junior clinicians. CONCLUSION: Off-label drug use is widespread in paediatric practice in China. Three-quarters of the prescriptions may potentially include inappropriate medication use, resulting in a daily economic burden of about ¥81 000 in 2020 in Gansu Province with 25 million inhabitants. The management of off-label drug use in paediatrics in China needs improvement.


Assuntos
Uso Off-Label , Uso Off-Label/estatística & dados numéricos , Humanos , Estudos Transversais , China , Criança , Pré-Escolar , Lactente , Masculino , Feminino , Padrões de Prática Médica/estatística & dados numéricos , Adolescente , Recém-Nascido , Prescrições de Medicamentos/estatística & dados numéricos
19.
bioRxiv ; 2024 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-38746211

RESUMO

Metal-ion-dependent nucleases play crucial roles in cellular defense and biotechnological applications. Time-resolved crystallography has resolved catalytic details of metal-ion-dependent DNA hydrolysis and synthesis, uncovering the essential roles of multiple metal ions during catalysis. The superfamily of His-Me nucleases is renowned for binding one divalent metal ion and requiring a conserved histidine to promote catalysis. Many His-Me family nucleases, including homing endonucleases and Cas9 nuclease, have been adapted for biotechnological and biomedical applications. However, it remains unclear how this single metal ion in His-Me nucleases, together with the histidine, promotes water deprotonation, nucleophilic attack, and phosphodiester bond breakage. By observing DNA hydrolysis in crystallo with His-Me I-PpoI nuclease as a model system, we proved that only one divalent metal ion is required during its catalysis. Moreover, we uncovered several possible deprotonation pathways for the nucleophilic water. Interestingly, binding of the single metal ion and water deprotonation are concerted during catalysis. Our results reveal catalytic details of His-Me nucleases, which is distinct from multi-metal-ion-dependent DNA polymerases and nucleases.

20.
Artigo em Inglês | MEDLINE | ID: mdl-38702270

RESUMO

BACKGROUND: The 2019 European Society of Cardiology (ESC) guidelines proposed a pre-test probability (PTP) model to determine the likelihood of coronary artery disease (CAD). However, the prediction accuracy of this model has not yet been evaluated in Chinese populations. This study aimed to validate the 2019 ESC-PTP model in predicting CAD using coronary computed tomography angiography (CCTA) outcomes in a Chinese population. METHODS: A total of 26,346 consecutive patients with suspected CAD who underwent CCTA were included. The 2019 ESC-PTP model and 2013 ESC-PTP model were calculated for each patient, considering age, sex, and the symptom of chest pain, and the patients were categorized into low-, intermediate-, and high-risk groups. The predictive performance of the 2019 ESC-PTP model was evaluated by comparing it with the 2013 ESC-PTP model and the observed prevalence of CAD from CCTA. RESULTS: Among the 11,234 patients analyzed in the study, 1896 (16.9%) patients were found to have obstructive CAD from CCTA. The 2019 ESC-PTP model had better calibration compared to the 2013 ESC-PTP model. After categorization, 80.9% of patients (67.9% in men and 94.4% in women) were in the same risk category as in the 2019 ESC-PTP model, but the risks of younger patients (7.5% versus 2.5%; P â€‹< â€‹0.001) and patients with non-anginal chest pain (13.7% versus 8.2%; P â€‹< â€‹0.001) were underestimated in the 2019 ESC-PTP model. CONCLUSION: The 2019 ESC-PTP model demonstrated a good calibration in predicting CAD in a Chinese population who underwent CCTA, but it exhibited an underestimation of CAD probability in younger patients and patients with non-anginal chest pain.

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