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1.
Sheng Wu Gong Cheng Xue Bao ; 40(9): 3072-3082, 2024 Sep 25.
Artículo en Chino | MEDLINE | ID: mdl-39319725

RESUMEN

Dextranase is an enzyme that specifically hydrolyzes the α-1, 6 glucoside bond. In order to improve the activity of dextranase from Arthrobacter oxidans KQ11, site-directed mutagenesis was used to modify the amino acids involved in the "tunnel-like binding site". A saturating mutation at position 507 was carried out on this basis. The mutant enzymes A356G, S357W, W507Y, and W507F with improved enzyme activities and catalytic efficiency were successfully obtained. Compared with wild type (WT), W507Y showed the specific activity increasing by 3.00 times, the kcat value increasing by 3.62 times, the Km value decreasing by 54%, and the catalytic efficiency (kcat/Km) increasing by 8.98 times. The three-dimensional structure analysis showed that the increase of the number of hydrogen bonds and the distance between "tunnel-like binding sites" were important factors affecting enzyme activity. Compared with WT, W507Y had a shortened distance from the residues on the other side of the "tunnel-like binding site", which made it easier to generate hydrogen binding forces. Accordingly, the substrate hydrolysis and product efflux were accelerated, which dramatically increased the enzyme activity and catalytic efficiency.


Asunto(s)
Arthrobacter , Dextranasa , Mutagénesis Sitio-Dirigida , Arthrobacter/enzimología , Arthrobacter/genética , Dextranasa/genética , Dextranasa/metabolismo , Dextranasa/química , Sitios de Unión , Mutación , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química
2.
J Cancer ; 15(17): 5577-5593, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-39308682

RESUMEN

The occurrence and development of hepatocellular carcinoma (HCC) are closely related to abnormal apoptosis. Brf1 is highly expressed in HCC and has clinical prognostic value. Here, attenuation of Brf1-induced apoptosis was found, and the related mechanism was explored. In the study, general bioinformatics data for Brf1 were obtained from The Human Protein Atlas (HPA). Analyses of the clinical prognostic value of Brf1 in HCC were performed with the Xiantao Academic web server using R software. The basic data were obtained from the GTEx database and TCGA database. Brf1 conditional knockout mice were obtained by repeated mating of C57BL/6 Brf1LoxP/LoxP and C57BL/6 NS5A-alb-Cre-ERT2 mice and verified by genotyping. Liver function measurements, hematoxylin and eosin staining (HE), and immunohistochemistry (IHC) were performed to explore the cause of mouse death after Brf1 knockout. The Brf1 knockdown HCC cell model was generated using lentiviral vector-based shRNA transduction. Cell proliferation assays, plate colony formation assays, anchorage-independent colony formation assays and mouse subcutaneous tumor models were used to evaluate the progression of HCC. Western blot (WB) analysis, flow cytometry, and TUNEL assays were used to detect apoptosis. DNA sequencing, transcriptomics, and proteomics analyses were carried out to explore the antiapoptotic mechanism of Brf1. We found that Brf1 was highly expressed in HCC and had clinical prognostic value. Brf1 knockout led to liver failure and hepatocyte apoptosis in mice. Downregulation of Brf1 slowed HCC cell proliferation, colony growth, and mouse subcutaneous tumor growth and increased the sensitivity of HCC cells to apoptosis induced by chemotherapy drugs. The expression of Brf1 was positively related to that of the apoptosis gene Bcl-2. The sequencing, transcriptomics and proteomics analyses consistently showed that energy metabolism played an important role in Brf1 function, that protein-protein interaction was the primary mode, and that organelles such as mitochondria were the main sites. In Conclusions, downregulation of Brf1 inhibits HCC development by inducing apoptosis. Energy metabolism plays an important role in Brf1 function. These results provide a scientific basis for combating HCC.

3.
Angew Chem Int Ed Engl ; : e202413898, 2024 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-39223782

RESUMEN

Antiferroelectric (AFE) has emerged as a promising branch of electroactive materials, due to their intriguing physical attributes stemming from the electric field-induced antipolar-to-polar phase transformation. However, the requirement of an extremely high electric field strength to switch adjacent sublattice polarization poses great challenges for exploiting molecular AFE system. Although photoirradiation is striking as a noncontact and nondestructive manipulation tool to optimize physical properties, the optical control of antiferroelectricity is still unexplored. Here, by adopting light-sensitive triiodide I3- anion into the 2D perovskite family, we have designed the first I3--intercalated molecular AFE of (t-ACH)2EA2Pb3I10(I3)0.5·((H3O)(H2O))0.5 (1, t-ACH = trans-4-aminomethyl-1-cyclohexanecarboxylate, EA = ethylammonium). The I3--intercalating gives an ultra-narrow bandgap of 1.65 eV with strong absorption. In terms of AFE structure, the anti-parallel alignment of electric dipoles results in a spontaneous polarization of 4.3 µC/cm2. Strikingly, 1 merely shows AFE behaviour in the dark even under ultrahigh voltage, while the field-induced ferroelectric state can be facilely obtained upon visible illumination. Such unprecedented photo-assisted phase switching ascribes to the incorporation of photoactive I3- anions, which reduce the AFE-to-ferroelectric switching barrier for 1. This pioneering work on the photo-assisting transformation of ferroic orders paves a new way to develop future photoactive materials with significant potential applications.

4.
BMC Gastroenterol ; 24(1): 313, 2024 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-39285368

RESUMEN

BACKGROUND: Good gastric preparation is indispensable for Magnetic-controlled Capsule Endoscopy (MCE) examination, but there is no consensus yet. We aim to explore the clinical application value of positioning exercises in improving the quality of MCE examination. METHODS: Clinical data of 326 patients who underwent MCE examination from January 2020 to December 2023 were collected. The included patients were divided into two groups: the conventional medication preparation group (CMP group, accepted mucosal cleansing medication only) and the positioning exercises group (PE group, accepted mucosal cleansing medication plus positioning exercises). A comparison was made between the two groups in terms of gastric cavity cleanliness score, visibility score, and detection rate of positive lesions. RESULTS: The examination time was (21.29 ± 5.82) minutes in the PE group and (30.54 ± 6.37) minutes in the CMP group, showing a significant difference between the two groups (P < 0.001). The total cleanliness score and visibility score in the CMP group were 15.89 ± 2.82 and 10.93 ± 2.12, respectively. In contrast, the total cleanliness score and visibility score in the PE group were 19.52 ± 2.26 and 15.09 ± 2.31, respectively. The PE group showed significantly better cleanliness scores and visibility scores in all six anatomical regions compared to the CMP group (All P < 0.001). However, there was no significant difference in the detection rate of positive lesions between the two groups (All P > 0.05). CONCLUSION: Positioning exercises before MCE examination can improve the quality of gastric mucosal images and reduce the duration of the examination for patients.


Asunto(s)
Endoscopía Capsular , Posicionamiento del Paciente , Humanos , Endoscopía Capsular/métodos , Masculino , Femenino , Persona de Mediana Edad , Adulto , Anciano , Mucosa Gástrica/patología , Mucosa Gástrica/diagnóstico por imagen , Mejoramiento de la Calidad , Catárticos/administración & dosificación
5.
Faraday Discuss ; 2024 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-39258887

RESUMEN

The only NMR-active oxygen isotope, oxygen-17 (17O), serves as a sensitive probe due to its large chemical shift range, the electric field gradient at the oxygen site, and the quadrupolar interaction. Consequently, 17O solid-state NMR offers unique insights into local structures and finds significant applications in the studies of disorder, reactivity, and host-guest chemistry. Despite recent advances in sensitivity enhancement, isotopic labeling, and NMR crystallography, the application of 17O solid-state NMR is still hindered by low natural abundance, costly enrichment, and challenges in handling spectrum signals. Density functional theory calculations and machine learning techniques offer an alternative approach to mapping the local crystal structures to NMR parameters. However, the lack of high-quality data remains a challenge, despite the establishment of some datasets. In this study, we implement and execute a high-throughput workflow combining AiiDA and CASTEP to evaluate the NMR parameters. Focusing on non-magnetic oxides, we have chosen over 7100 binary, ternary, and quaternary compounds from the Materials Project database and performed calculations. Furthermore, using various descriptors for the local crystalline environments, we model the 17O NMR parameters using machine learning techniques, further enhancing our ability to predict and understand 17O NMR parameters in oxide crystals.

6.
Angew Chem Int Ed Engl ; : e202411875, 2024 Sep 09.
Artículo en Inglés | MEDLINE | ID: mdl-39251564

RESUMEN

Birefringent crystal, which has the capacity to manipulate polarization light, holds an indispensable position in optics and optoelectronics, while it remains challenging to fulfill the modulation of birefringence. Here, we present wide spectral photo-pyroelectric effect in a silver-based hybrid pyroelectric, (N-CHM)Ag2I3 (N-CHM = N-cyclohexylmethylamine), serving as a feasible strategy to regulate birefringence through light stimuli. As the first silver-based hybrid pyroelectric, (N-CHM)Ag2I3 exhibits strong room-temperature photo-pyroelectricity with a large polarization of ~3.23 µC/cm2 and high voltage responsivity of ~0.96 m2/C across the UV-NIR spectral region. Strikingly, the photomodulation of its in-plane birefringence is established through pyroelectric effect, giving a saturation value of ~1.68×10-2 that is among the highest level achieved to date. This study on the birefringence photomodulation of lead-free hybrid pyroelectric is anticipated to boost future development of new smart optical and optoelectronic devices.

7.
Int J Cancer ; 2024 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-39109820

RESUMEN

Acute myeloid leukemia (AML) can manifest as de novo AML (dn-AML) or secondary AML (s-AML), with s-AML being associated with inferior survival and distinct genomic characteristics. The underlying reasons for this disparity remain to be elucidated. In this multicenter study, next-generation sequencing (NGS) was employed to investigate the mutational landscape of AML in 721 patients from June 2020 to May 2023.Genetic mutations were observed in 93.34% of the individuals, with complex variations (more than three gene mutations) present in 63.10% of them. TET2, ASXL1, DNMT3A, TP53 and SRSF2 mutations showed a higher prevalence among older individuals, whereas WT1 and KIT mutations were more commonly observed in younger patients. BCOR, BCORL1, ZRSR2, ASXL1 and SRSF2 exhibited higher mutation frequencies in males. Additionally, ASXL1, NRAS, PPMID, SRSF2, TP53 and U2AF1 mutations were more common in patients with s-AML, which PPM1D was more frequently associated with therapy-related AML (t-AML). Advanced age and hyperleukocytosis independently served as adverse prognostic factors for both types of AML; however, s-AML patients demonstrated a greater number of monogenic adverse prognostic factors compared to dn-AML cases (ASXL1, PPM1D, TP53 and U2AF1 in s-AML vs. FLT3, TP53 and U2AF1 in dn-AML). Age and sex-related gene mutations suggest epigenetic changes may be key in AML pathogenesis. The worse prognosis of s-AML compared to dn-AML could be due to the older age of s-AML patients and more poor-prognosis gene mutations. These findings could improve AML diagnosis and treatment by identifying potential therapeutic targets and risk stratification biomarkers.

8.
Zhongguo Shi Yan Xue Ye Xue Za Zhi ; 32(4): 1217-1223, 2024 Aug.
Artículo en Chino | MEDLINE | ID: mdl-39192423

RESUMEN

OBJECTIVE: To analyze the risk factors of Epstein-Barr virus (EBV) infection after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and its impact on survival. METHODS: The clinical data of 347 patients who underwent their first allo-HSCT in our hospital from January 2014 to June 2021 were retrospectively analyzed. Patients were divided into EBV (n =114) and Non-EBV (n =233) groups according to whether they were infected with EBV. The incidence of EBV infection after allo-HSCT was calculated, and the risk factors of EBV infection were analyzed. RESULTS: A total of 114(32.8%) patients presented EBV infection (all peripheral blood EBV-DNA were positive). EBV infection occurred in 88 patients within 100 days after transplantation, which accounted for 77.2% of all patients with EBV infection. 5 cases (1.44%) were confirmed as post-transplant lymphoproliferative disorder (PTLD). The median onset time of patients was 57(7-486) days after transplantation. Multivariate analysis showed that the use of ATG/ATG-F, occurrence of CMV viremia, and grade III-IV aGVHD were risk factors for EBV infection. Furthermore, compared to BUCY, the use of intensified preconditioning regimens containing FA/CA was significantly increased the risk of EBV infection. CONCLUSION: EBV infection is a common complication after allo-HSCT. Intensified preconditioning regimens, use of ATG/ATG-F, CMV viremia and grade III to IV aGVHD increase the risk of EBV infection after allo-HSCT.


Asunto(s)
Infecciones por Virus de Epstein-Barr , Trasplante de Células Madre Hematopoyéticas , Herpesvirus Humano 4 , Trasplante Homólogo , Humanos , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Estudios Retrospectivos , Factores de Riesgo , Trasplante Homólogo/efectos adversos , Acondicionamiento Pretrasplante/efectos adversos , Enfermedad Injerto contra Huésped/etiología , Trastornos Linfoproliferativos/etiología , Incidencia , Femenino , Masculino
9.
Artículo en Inglés | MEDLINE | ID: mdl-39159885

RESUMEN

OBJECTIVE: This study aims to evaluate the perioperative and midterm oncological outcomes of robotic-assisted thoracic surgery extended thymectomy for patients with large resectable thymomas compared with small thymomas. METHODS: This retrospective single-center study included 204 patients with thymomas who underwent robotic-assisted thoracic surgery extended thymectomy between January 2003 and February 2024. Patients were divided into 2 groups based on the thymoma size (5-cm threshold). RESULTS: The study comprised 114 patients (55.9%) in the small thymoma group and 90 patients (44.1%) in the large thymoma group. No significant differences were found between the groups regarding gender, age, proportion of elderly patients, or pathologic high-risk classifications. Apart from a longer operative time (P = .009) in the large thymoma group, no differences were observed between the 2 groups regarding surgical parameters and postoperative outcomes. No deaths occurred within 30 days in either group. During a median follow-up of 61.0 months (95% CI, 48.96-73.04), 4 patients experienced recurrence (1.96%). No significant differences in the 5-year overall survival (P = .25) or recurrence-free survival (P = .43) were observed between groups. CONCLUSIONS: Robotic-assisted thoracic surgery extended thymectomy is technically feasible, safe, and effective for treating large resectable thymomas. Moreover, midterm outcomes for patients with completely resected large thymomas were comparable to those with small thymomas during a median follow-up period of up to 5 years.

10.
Chem Mater ; 36(14): 6765-6776, 2024 Jul 23.
Artículo en Inglés | MEDLINE | ID: mdl-39070670

RESUMEN

Due to their versatile composition and customizable properties, A2BC Heusler alloys have found applications in magnetic refrigeration, magnetic shape memory effects, permanent magnets, and spintronic devices. The discovery of all-d-metal Heusler alloys with improved mechanical properties compared to those containing main group elements presents an opportunity to engineer Heusler alloys for energy-related applications. Using high-throughput density-functional theory calculations, we screened magnetic all-d-metal Heusler compounds and identified 686 (meta)stable compounds. Our detailed analysis revealed that the inverse Heusler structure is preferred when the electronegativity difference between the A and B/C atoms is small, contrary to conventional Heusler alloys. Additionally, our calculations of Pugh ratios and Cauchy pressures demonstrated that ductile and metallic bonding are widespread in all-d-metal Heuslers, supporting their enhanced mechanical behavior. We identified 49 compounds with a double-well energy surface based on Bain path calculations and magnetic ground states, indicating their potential as candidates for magnetocaloric and shape memory applications. Furthermore, by calculating the free energies, we propose that 11 compounds exhibit structural phase transitions and suggest isostructural substitutions to enhance the magnetocaloric effect.

11.
Int Immunopharmacol ; 139: 112672, 2024 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-39032469

RESUMEN

The resistance of osteosarcoma (OS) to ionizing radiation (IR) is an obstacle for effective patient treatment. Apurinic/apyrimidinic endonuclease-reduction/oxidation factor 1 (APE1/Ref-1) is a multifunctional protein with DNA repair and reduction/oxidation (redox) activities. We previously revealed the role of APE1 in OS radioresistance; however, whether the redox activity of APE1 is involved in OS radioresistance is unclear. APE1 regulates the activation of ataxia-telangiectasia mutated (ATM), an initiator of DNA damage response that mediates radioresistance in other cancers. The role of APE1 redox activity and ATM activation in OS radioresistance is unknown. Our study revealed that IR increased APE1 expression and ATM activation in OS cells, and APE1 directly regulated ATM activation by its redox activity. The combined use of an APE1 redox inhibitor and ATM inhibitor effectively sensitized OS cells to IR in vitro and in vivo. Mechanistically, the increased radiosensitization of OS cells by the combined use of the two inhibitors was mediated by increased ferroptosis. Co-treatment with the two inhibitors significantly decreased expression of the common targeted transcription factor P53 compared with single inhibitor treatment. Collectively, APE1 redox activity, ATM activation and their crosstalk play important roles in the resistance of OS to irradiation. Synergetic inhibition of APE1 redox activity and ATM activation sensitized OS cells to IR by inducing ferroptosis, which provides a promising strategy for OS radiotherapy.


Asunto(s)
Proteínas de la Ataxia Telangiectasia Mutada , Neoplasias Óseas , ADN-(Sitio Apurínico o Apirimidínico) Liasa , Ferroptosis , Osteosarcoma , Oxidación-Reducción , Radiación Ionizante , Osteosarcoma/radioterapia , Osteosarcoma/metabolismo , Osteosarcoma/tratamiento farmacológico , ADN-(Sitio Apurínico o Apirimidínico) Liasa/metabolismo , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Proteínas de la Ataxia Telangiectasia Mutada/antagonistas & inhibidores , Humanos , Ferroptosis/efectos de los fármacos , Línea Celular Tumoral , Animales , Neoplasias Óseas/metabolismo , Neoplasias Óseas/tratamiento farmacológico , Neoplasias Óseas/radioterapia , Tolerancia a Radiación/efectos de los fármacos , Ratones , Ratones Desnudos , Ensayos Antitumor por Modelo de Xenoinjerto , Propionatos , Benzoquinonas
12.
J Inorg Biochem ; 259: 112664, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39018747

RESUMEN

HIV-1 reverse transcriptase (RT) inhibitors play a crucial role in the treatment of HIV by preventing the activity of the enzyme responsible for the replication of the virus. The HIV-1 Tat protein binds to transactivation response (TAR) RNA and recruits host factors to stimulate HIV-1 transcription. We have created a small library consisting of 4 × 6 polypyridyl Ru(II) complexes that selectively bind to TAR RNA, with targeting groups specific to HIV-1 TAR RNA. The molecule design was conducted by introducing hydroxyl or methoxy groups into an established potent TAR binder. The potential TAR binding ability was analysis from nature charge population and electrostatic potential by quantum chemistry calculations. Key modifications were found to be R1 and R3 groups. The most potent and selective TAR RNA binder was a3 with R1 = OH, R2 = H and R3 = Me. Through molecular recognition of hydrogen bonds and electrostatic attraction, they were able to firmly and selectively bind HIV-1 TAR RNA. Furthermore, they efficiently obstructed the contact between TAR RNA and Tat protein, and inhibited the reverse transcription activity of HIV-1 RT. The polypyridyl Ru(II) complexes were chemical and photo-stable, and sensitive and selective spectroscopic responses to TAR RNA. They exhibited little toxicity towards normal cells. Hence, this study might offer significant drug design approaches for researching AIDS and other illnesses associated with RT, including HCV, EBOV, and SARS-CoV-2. Moreover, it could contribute to fundamental research on the interactions of inorganic transition metal complexes with biomolecules.


Asunto(s)
Complejos de Coordinación , Transcriptasa Inversa del VIH , VIH-1 , ARN Viral , Inhibidores de la Transcriptasa Inversa , Rutenio , Rutenio/química , VIH-1/efectos de los fármacos , VIH-1/enzimología , Humanos , Transcriptasa Inversa del VIH/antagonistas & inhibidores , Transcriptasa Inversa del VIH/metabolismo , Transcriptasa Inversa del VIH/química , Relación Estructura-Actividad , Inhibidores de la Transcriptasa Inversa/farmacología , Inhibidores de la Transcriptasa Inversa/química , Complejos de Coordinación/farmacología , Complejos de Coordinación/química , ARN Viral/metabolismo , Fármacos Anti-VIH/farmacología , Fármacos Anti-VIH/química , Duplicado del Terminal Largo de VIH/efectos de los fármacos
13.
J Sep Sci ; 47(14): e2400288, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39034832

RESUMEN

Dalbergia odorifera is a natural product rich in pharmacological ingredients, but the comprehensive characterization and rapid profiling of active components remain a challenge. Thus, an integrated data mining and identification strategy was exploited to efficiently identify the chemical constituents and screen acetylcholinesterase inhibitors (AChEIs) through affinity ultrafiltration and ultra-high-performance liquid chromatography-mass spectrometry (AUF-UHPLC-MS). As a result, polygonal mass defect filtering, diagnostic product ions, and neutral loss rules were created for rapid structural classification and component identification. A total of 140 flavonoids were tentatively characterized, including 41 isoflavonoids, 23 flavanones, 21 isoflavans, 19 flavones and flavonols, 13 neoflavonoids, 11 isoflavanones, seven flavone glycosides, and five chalcones. Subsequently, six natural AChEIs including tectorigenin, fisetin, dalbergin, pterostilbene, isoliquiritigenin, and biochanin A were screened out using AUF-UHPLC-MS and molecular docking. Meanwhile, the AChE inhibitory activities of the six compounds were assessed in vitro, tectorigenin, fisetinand, and dalbergin have moderate inhibitory activity. In conclusion, a novel strategy for systematic characterization and further screening of active compounds in natural products was established, which provides a material basis for quality control of Dalbergia odorifera.


Asunto(s)
Inhibidores de la Colinesterasa , Dalbergia , Espectrometría de Masas en Tándem , Ultrafiltración , Inhibidores de la Colinesterasa/química , Inhibidores de la Colinesterasa/análisis , Dalbergia/química , Cromatografía Líquida de Alta Presión , Acetilcolinesterasa/química , Acetilcolinesterasa/metabolismo , Simulación del Acoplamiento Molecular , Flavonoides/química , Flavonoides/análisis , Estructura Molecular , Extractos Vegetales/química
14.
ISME J ; 18(1)2024 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-39083023

RESUMEN

The last two decades have seen nitrogen/iron-transforming bacteria at the forefront of new biogeochemical discoveries, such as anaerobic ammonium oxidation coupled to ferric iron reduction (feammox) and lithoautotrophic nitrate-reducing ferrous iron-oxidation (NRFeOx). These emerging findings continue to expand our knowledge of the nitrogen/iron cycle in nature and also highlight the need to re-understand the functional traits of the microorganisms involved. Here, as a proof-of-principle, we report compelling evidence for the capability of an NRFeOx enrichment culture to catalyze the feammox process. Our results demonstrate that the NRFeOx culture predominantly oxidizes NH4+ to nitrogen gas, by reducing both chelated nitrilotriacetic acid (NTA)-Fe(III) and poorly soluble Fe(III)-bearing minerals (γ-FeOOH) at pH 4.0 and 8.0, respectively. In the NRFeOx culture, Fe(II)-oxidizing bacteria of Rhodanobacter and Fe(III)-reducing bacteria of unclassified_Acidobacteriota coexisted. Their relative abundances were dynamically regulated by the supplemented iron sources. Metagenomic analysis revealed that the NRFeOx culture contained a complete set of denitrifying genes along with hao genes for ammonium oxidation. Additionally, numerous genes encoding extracellular electron transport-associated proteins or their homologs were identified, which facilitated the reduction of extracellular iron by this culture. More broadly, this work lightens the unexplored potential of specific microbial groups in driving nitrogen transformation through multiple pathways and highlights the essential role of microbial iron metabolism in the integral biogeochemical nitrogen cycle.


Asunto(s)
Compuestos de Amonio , Nitratos , Oxidación-Reducción , Nitratos/metabolismo , Compuestos de Amonio/metabolismo , Anaerobiosis , Compuestos Férricos/metabolismo , Hierro/metabolismo , Compuestos Ferrosos/metabolismo , Nitrógeno/metabolismo , Bacterias/metabolismo , Bacterias/genética , Bacterias/clasificación
15.
J Surg Case Rep ; 2024(5): rjae375, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38826858

RESUMEN

Perforation of Meckel's diverticulum caused by heterotopic pancreas is a rare condition. Despite recent improvements in imaging studies, Meckel"'s diverticulitis and heterotopic pancreas are difficult to diagnose preoperatively and are often diagnosed during autopsy or laparotomy. Symptomatic patients are typically >1 year, and cases of infants displaying symptoms are rarely reported. We report a rare case of heterotopic pancreas in Meckel's diverticulum causing perforation in an infant. In cases of infants presenting with unexplained acute abdominal pain, there should be a high index of suspicion for congenital gastrointestinal malformations. Prompt action in the form of exploratory laparotomy or laparoscopy is crucial to prevent the escalation of complications and to definitively confirm the diagnosis.

16.
Org Lett ; 26(23): 4992-4997, 2024 Jun 14.
Artículo en Inglés | MEDLINE | ID: mdl-38842460

RESUMEN

A metal-free and mild approach for constructing 5-amino-1,2-selenazole skeletons by NBS/KSeCN-mediated N-selenocyanation and nucleophilic cyclization of ß-enaminones has been developed. Various isoselenazole compounds and the isoselenazolyl derivatives of anti-inflammatory medicines, including isosepac, oxaprozin, and ibuprofen, have been obtained with good yields. This efficient, "one-pot", and atomic economy strategy may represent an alternative route for the construction of a 1,2-selenazole framework via the "+SeCN" pathway and provide new access to heterocycles containing a Se-N bond.

17.
Inorg Chem ; 63(26): 12342-12349, 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38904258

RESUMEN

As a typical RNA virus, the genetic information on HIV-1 is entirely stored in RNA. The reverse transcription activity of HIV-1 reverse transcriptase (RT) plays a crucial role in the replication and transmission of the virus. Non-nucleoside RT inhibitors (NNRTIs) block the function of RT by binding to the RNA binding site on RT, with very few targeting viral RNA. In this study, by transforming planar conjugated ligands into a spiro structure, we convert classical Ru(II) DNA intercalators into a nonintercalator. This enables selective binding to HIV-1 transactivation response (TAR) RNA on the outer side of nucleic acids through dual interactions involving hydrogen bonds and electrostatic attraction, effectively inhibiting HIV-1 RT and serving as a selective fluorescence probe for TAR RNA.


Asunto(s)
Transcriptasa Inversa del VIH , VIH-1 , Inhibidores de la Transcriptasa Inversa , Rutenio , Transcriptasa Inversa del VIH/antagonistas & inhibidores , Transcriptasa Inversa del VIH/metabolismo , Inhibidores de la Transcriptasa Inversa/química , Inhibidores de la Transcriptasa Inversa/farmacología , Inhibidores de la Transcriptasa Inversa/metabolismo , Ligandos , VIH-1/enzimología , VIH-1/efectos de los fármacos , Rutenio/química , Rutenio/farmacología , ARN Viral/metabolismo , ARN Viral/química , Compuestos de Espiro/química , Compuestos de Espiro/farmacología , Compuestos de Espiro/metabolismo , Complejos de Coordinación/química , Complejos de Coordinación/farmacología , Complejos de Coordinación/síntesis química , Sustancias Intercalantes/química , Sustancias Intercalantes/farmacología , Estructura Molecular , Humanos , Fármacos Anti-VIH/química , Fármacos Anti-VIH/farmacología , Duplicado del Terminal Largo de VIH , Sitios de Unión
18.
Materials (Basel) ; 17(11)2024 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-38893899

RESUMEN

Hydrogenation-Disproportionation-Desorption-Recombination (HDDR) Nd2Fe14B particles have excellent magnetic properties, but the magnetic properties of powder are not uniform across different particle sizes. The remanence and maximum magnetic energy products of samples with a particle size of 120 µm are 14.0 kGs and 41.35 MGOe, while the products of samples with a particle size of 60 µm are only 13.3 kGs and 36.31 MGOe. The macroscopic morphology of HDDR Nd2Fe14B particles and the gradient distribution of microstructures in different micro-regions were observed. By modifying the macroscopic morphology of the particles, the poorly oriented clusters on the surface of the particles were precisely eliminated, and the remanence and maximum magnetic energy products of the particles increased to 14.5 kGs and 45 MGOe, respectively. Compared with the original particles, the samples after mechanical grinding had better grain arrangement. The effects of the nanocrystalline c-axis and field misalignment angle θ on the magnetic properties of HDDR Nd2Fe14B particles were investigated through micromagnetic simulation. The targeted removal of macroscopic defects on the particle surface contributed to a 3.6% increase in remanence and an 8.8% increase in the maximum magnetic energy product, offering a promising approach to enhance the microstructure of high-performance HDDR Nd2Fe14B particles.

19.
J Colloid Interface Sci ; 674: 315-325, 2024 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-38936088

RESUMEN

HYPOTHESIS: Elucidation of the micro-mechanisms of sol-gel transition of gelling glucans with different glycosidic linkages is crucial for understanding their structure-property relationship and for various applications. Glucans with distinct molecular chain structures exhibit unique gelation behaviors. The disparate gelation phenomena observed in two methylated glucans, methylated (1,3)-ß-d-glucan of curdlan (MECD) and methylated (1,4)-ß-d-glucan of cellulose (MC), notwithstanding their equivalent degrees of substitution, are intricately linked to their unique molecular architectures and interactions between glucan and water. EXPERIMENTS: Density functional theory and molecular dynamics simulations focused on the electronic property distinctions between MECD and MC, alongside conformational variations during thermal gelation. Inline attenuated total reflection Fourier transform infrared spectroscopy tracked secondary structure alterations in MECD and MC. To corroborate the simulation results, additional analyses including circular dichroism, rheology, and micro-differential scanning calorimetry were performed. FINDINGS: Despite having similar thermally induced gel networks, MECD and MC display distinct physical gelation patterns and molecular-level conformational changes during gelation. The network of MC gel was formed via a "coil-to-ring" transition, followed by ring stacking. In contrast, the MECD gel comprised compact irregular helices accompanied by notable volume shrinkage. These variations in gelation behavior are ascribed to heightened hydrophobic interactions and diminished hydrogen bonding in both systems upon heating, resulting in gelation. These findings provide valuable insights into the microstructural changes during gelation and the thermo-gelation mechanisms of structurally similar polysaccharides.


Asunto(s)
Geles , Simulación de Dinámica Molecular , Geles/química , Metilación , Temperatura , beta-Glucanos/química , Glicósidos/química , Teoría Funcional de la Densidad , Glucanos/química , Celulosa/química
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