Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 578
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-38721831

RESUMO

STUDY DESIGN: Finite element analysis. OBJECTIVE: To investigate the biomechanical effect of four posterior fixation tcehniques on stability and adjacent segment degeneration in treating thoracolumbar burst fractures with osteoporosis. SUMMARY OF BACKGROUND DATA: In terms of stability and adjacent segment degeneration, there remains no consensus or guidelines on the optimal technique for the treatment of thoracolumbar burst fractures in patients with osteoporosis. METHODS: Images of CT scans were imported into MIMICS and further processed by Geomagic to build 3-dimensional models of the T10-L5 region. A v-shaped osteotomy was performed on the L1 vertebral body to simulate a burst fracture in the setting of osteoporosis. Subsequently, four fixation techniques were designed using SolidWorks software. Range of motion (ROM) of the global spine, ROM distribution, ROM of adjacent segment, Von Mises stress on adjacent intervertebral discs and facet joints were analyzed. RESULTS: Among the four groups, the cortical bone screw fixation (CBT) showed the highest global ROM at 1.86°, while long-segmented pedicle screw fixation (LSPS) had the lowest global ROM at 1.25°. The LSPS had the smallest percentage of ROM of fractured vertebral body to fixed segment at 75.04%, suggesting the highest stability after fixation. The maximum ROM of the adjacent segment was observed in the CBT at 1.32°, while the LSPS exhibited the smallest at 0.89°. However, the LSPS group experienced larger maximum stress on the adjacent intervertebral discs (9.60MPa) and facet joints (3.36MPa), indicating an increasing risk of adjacent segment disease. CONCLUSION: LSPS provided the greatest stability, while CBT provided the smallest amount of stability. However, the elevated stress on adjacent intervertebral discs and facet joints after LSPS fixation increased the possibility of adjacent segment degeneration. Cement-augmented pedicle screw fixation (CAS) and combined cortical bone screw and pedicle screw fixation (CBT-PS) demonstrated significant biomechanical advantages in providing moderate fixation strength while reducing stress on the intervertebral discs and facet joints.

2.
J Phys Chem Lett ; 15(19): 5150-5158, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38712816

RESUMO

Intrinsic boundaries formed by grain stacks of randomly oriented perovskite crystallites seriously restrict charge transport in the resultant photovoltaic devices, whereas direct passivation of these defects remains unexplored, and it is desirable to modulate perovskite growth with uniform orientation. Herein, we report a simple but effective method to regulate perovskite crystallization by employing a volatile and polymerizable monomer of hydroxyethyl methacrylate (HEMA), which can simultaneously interact with both FA+ and Pb2+ via hydrogen and coordination bonding, respectively, to seed perovskite crystallization with accelerated nucleation and retarded crystal growth. Upon thermal annealing, the gradual volatilization and partial self-condensation of the HEMA drive the perovskite growth perpendicularly to the substrate, leading to largely suppressed defect states, improved crystallinity, and a reduced Young's modulus of the perovskite film. As a result, champion efficiencies exceeding 24 and 22% with improved operational and mechanical stability of the optimized perovskite solar cells based on rigid and flexible substrates were finally achieved.

3.
Med Biol Eng Comput ; 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38727759

RESUMO

In clinical practice, the morphology of the left atrial appendage (LAA) plays an important role in the selection of LAA closure devices for LAA closure procedures. The morphology determination is influenced by the segmentation results. The LAA occupies only a small part of the entire 3D medical image, and the segmentation results are more likely to be biased towards the background region, making the segmentation of the LAA challenging. In this paper, we propose a lightweight attention mechanism called fusion attention, which imitates human visual behavior. We process the 3D image of the LAA using a method that involves overview observation followed by detailed observation. In the overview observation stage, the image features are pooled along the three dimensions of length, width, and height. The obtained features from the three dimensions are then separately input into the spatial attention and channel attention modules to learn the regions of interest. In the detailed observation stage, the attention results from the previous stage are fused using element-wise multiplication and combined with the original feature map to enhance feature learning. The fusion attention mechanism was evaluated on a left atrial appendage dataset provided by Liaoning Provincial People's Hospital, resulting in an average Dice coefficient of 0.8855. The results indicate that the fusion attention mechanism achieves better segmentation results on 3D images compared to existing lightweight attention mechanisms.

4.
Small ; : e2401624, 2024 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-38773869

RESUMO

The poor machinability of halide perovskite crystals severely hampered their practical applications. Here a high-throughput growth method is reported for armored perovskite single-crystal fibers (SCFs). The mold-embedded melt growth (MEG) method provides each SCF with a capillary quartz shell, thus guaranteeing their integrality when cutting and polishing. Hundreds of perovskite SCFs, exemplified by CsPbBr3, CsPbCl3, and CsPbBr2.5I0.5, with customized dimensions (inner diameters of 150-1000 µm and length of several centimeters), are grown in one batch, with all the SCFs bearing homogeneity in shape, orientation, and optical/electronic properties. Versatile assembly protocols are proposed to directly integrate the SCFs into arrays. The assembled array detectors demonstrated low-level dark currents (< 1 nA) with negligible drift, low detection limit (< 44.84 nGy s-1), and high sensitivity (61147 µC Gy-1 cm-2). Moreover, the SCFs as isolated pixels are free of signal crosstalk while showing uniform X-ray photocurrents, which is in favor of high spatial resolution X-ray imaging. As both MEG and the assembly of SCFs involve none sophisticated processes limiting the scalable fabrication, the strategy is considered to meet the preconditions of high-throughput productions.

5.
Inflammopharmacology ; 2024 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-38761314

RESUMO

Cancer, a chronic disease characterized by uncontrolled cell development, kills millions of people globally. The WHO reported over 10 million cancer deaths in 2020. Anticancer medications destroy healthy and malignant cells. Cancer treatment induces neuropathy. Anticancer drugs cause harm to spinal cord, brain, and peripheral nerve somatosensory neurons, causing chemotherapy-induced neuropathic pain. The chemotherapy-induced mechanisms underlying neuropathic pain are not fully understood. However, neuroinflammation has been identified as one of the various pathways associated with the onset of chemotherapy-induced neuropathic pain. The neuroinflammatory processes may exhibit varying characteristics based on the specific type of anticancer treatment delivered. Neuroinflammatory characteristics have been observed in the spinal cord, where microglia and astrocytes have a significant impact on the development of chemotherapy-induced peripheral neuropathy. The patient's quality of life might be affected by sensory deprivation, loss of consciousness, paralysis, and severe disability. High cancer rates and ineffective treatments are associated with this disease. Recently, histone deacetylases have become a novel treatment target for chemotherapy-induced neuropathic pain. Chemotherapy-induced neuropathic pain may be treated with histone deacetylase inhibitors. Histone deacetylase inhibitors may be a promising therapeutic treatment for chemotherapy-induced neuropathic pain. Common chemotherapeutic drugs, mechanisms, therapeutic treatments for neuropathic pain, and histone deacetylase and its inhibitors in chemotherapy-induced neuropathic pain are covered in this paper. We propose that histone deacetylase inhibitors may treat several aspects of chemotherapy-induced neuropathic pain, and identifying these inhibitors as potentially unique treatments is crucial to the development of various chemotherapeutic combination treatments.

6.
Int J Gen Med ; 17: 1193-1211, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38559590

RESUMO

Background: Esophageal squamous cell carcinoma (ESCC) is an aggressive and fatal malignancy that leads to epithelial cancer. The association between epithelial cell heterogeneity, prognosis, and immune response in this cancer remains uncertain. This study aimed to investigate epithelial cell heterogeneity in ESCC and develop a predictive risk model using the identified cell types. Methods: Single-cell RNA sequencing (scRNA-seq) and differential ESCC gene data were accessed from the Gene Expression Omnibus. Functional enrichment analysis, inferCNV, cell development trajectories, and intercellular communication were analyzed following epithelial cell characterization. Differentially expressed ESCC (n = 773) and epithelial cell marker genes (n = 3407) were intersected to obtain core genes, and epithelial cell-related prognostic genes were identified. LASSO regression analysis was used to construct a prognostic model. The external dataset GSE53624 was used to further validate the stability of the model. Drug sensitivity predictions, and immune cell infiltration were analyzed. Molecular docking clarified the possible therapeutic role of ß-sitosterol in ESCC. Finally, wound healing assay, cell colony, and transwell assay were constructed to detect the effects of the core gene PDLIM2 on ESCC cell proliferation, invasion, and migration. Results: Eight cell clusters were identified, and epithelial cells were categorized into tumor and paratumor groups. The tumor group possessed more chromosomal variants than the paratumor group. Epithelial cells were associated with multiple cell types and significantly correlated with the Wnt, transforming growth factor, and epidermal growth factor signaling pathways. From 231 intersected genes, five core genes were screened for use in the risk model: CTSL, LAPTM4B, MYO10, NCF2, and PDLIM2. These genes may contribute to the cancerous transformation of normal esophageal epithelial cells and thereby act as biomarkers and potential therapeutic targets in patients with ESCC. ß-Sitosterol furthermore displayed excellent docking potential with these genes. Meanwhile, further experiments demonstrated that the gene PDLIM2 plays a major role in the progression of oesophageal squamous carcinoma. Conclusion: We successfully developed a risk model for the prognosis of ESCC based on epithelial cells that addresses the response of ESCC to immunotherapy and offers novel cancer treatment options.

7.
Int J Environ Health Res ; : 1-13, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38591755

RESUMO

To examine the mediatory role of nature connectedness between tree visibility through windows and mental wellbeing, we conducted a questionnaire survey and examined the mediation effect using both cross-sectional and semi-longitudinal mediation models. We evaluated nature connectedness using the Inclusion of Nature in Self (INS) scale and the Connectedness to Nature Scale (CNS) and measured mental wellbeing using the WHO-5 wellbeing index. Our results showed that participants who could see at least three trees through their windows reported higher levels of both nature connectedness and mental wellbeing compared to those without such visibility. Nature connectedness significantly mediated the relationship between the visibility of trees through windows and mental wellbeing, albeit with a somewhat limited effect. More broadly, this study provides additional evidence in support of the "3" component of the 3-30-300 "rule" for equitable access to greenspace in cities.

9.
Front Sports Act Living ; 6: 1381895, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38606114

RESUMO

With the awakening of female consciousness, women's participation in sports has gradually gained autonomy and agency. However, Chinese women still face numerous restrictions in combat sports, hindering the development of this industry. Based on years of practice and research experience in the field, we summarize some general and specific issues, such as stigmatization and the constraints of traditional Chinese thinking. These issues need attention and consideration in the pursuit of gender equality in sports in the future.

10.
EBioMedicine ; 103: 105127, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38677183

RESUMO

BACKGROUND: Obesity drives maladaptive changes in the white adipose tissue (WAT) which can progressively cause insulin resistance, type 2 diabetes mellitus (T2DM) and metabolic dysfunction-associated liver disease (MASLD). Obesity-mediated loss of WAT homeostasis can trigger liver steatosis through dysregulated lipid pathways such as those related to polyunsaturated fatty acid (PUFA)-derived oxylipins. However, the exact relationship between oxylipins and metabolic syndrome remains elusive and cross-tissue dynamics of oxylipins are ill-defined. METHODS: We quantified PUFA-related oxylipin species in the omental WAT, liver biopsies and plasma of 88 patients undergoing bariatric surgery (female N = 79) and 9 patients (female N = 4) undergoing upper gastrointestinal surgery, using UPLC-MS/MS. We integrated oxylipin abundance with WAT phenotypes (adipogenesis, adipocyte hypertrophy, macrophage infiltration, type I and VI collagen remodelling) and the severity of MASLD (steatosis, inflammation, fibrosis) quantified in each biopsy. The integrative analysis was subjected to (i) adjustment for known risk factors and, (ii) control for potential drug-effects through UPLC-MS/MS analysis of metformin-treated fat explants ex vivo. FINDINGS: We reveal a generalized down-regulation of cytochrome P450 (CYP)-derived diols during obesity conserved between the WAT and plasma. Notably, epoxide:diol ratio, indicative of soluble epoxide hydrolyse (sEH) activity, increases with WAT inflammation/fibrosis, hepatic steatosis and T2DM. Increased 12,13-EpOME:DiHOME in WAT and liver is a marker of worsening metabolic syndrome in patients with obesity. INTERPRETATION: These findings suggest a dampened sEH activity and a possible role of fatty acid diols during metabolic syndrome in major metabolic organs such as WAT and liver. They also have implications in view of the clinical trials based on sEH inhibition for metabolic syndrome. FUNDING: Wellcome Trust (PS3431_WMIH); Duke-NUS (Intramural Goh Cardiovascular Research Award (Duke-NUS-GCR/2022/0020); National Medical Research Council (OFLCG22may-0011); National Institute of Environmental Health Sciences (Z01 ES025034); NIHR Imperial Biomedical Research Centre.


Assuntos
Tecido Adiposo Branco , Fígado Gorduroso , Obesidade , Oxilipinas , Humanos , Obesidade/metabolismo , Obesidade/complicações , Feminino , Fígado Gorduroso/metabolismo , Fígado Gorduroso/patologia , Fígado Gorduroso/etiologia , Masculino , Oxilipinas/metabolismo , Tecido Adiposo Branco/metabolismo , Tecido Adiposo Branco/patologia , Pessoa de Meia-Idade , Adulto , Inflamação/metabolismo , Inflamação/patologia , Fígado/metabolismo , Fígado/patologia , Biomarcadores , Espectrometria de Massas em Tandem
11.
Small ; : e2401489, 2024 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-38661053

RESUMO

To mitigate the environmental impact of the improper disposal of spent LiFePO4 batteries and reduce resource waste, the development of LiFePO4 recycling technologies is of paramount importance. Meanwhile, olivine-structured NaFePO4 in sodium-ion batteries has received great attention, due to its high theoretical specific capacity of 154 mAh g-1 and excellent stability. However, olivine NaFePO4 only can be synthesized from olivine LiFePO4. Accordingly, in this proposal, developing the continuous flow electrochemical solid-liquid reactor-based metal ion insertion technology is to utilize the olivine FePO4, recycled from LiFePO4, and to synthesize NaFePO4. Additionally, by employing I- as the reducing agent, NaFePO4 is successfully synthesized with a discharge-specific capacity of 134 mAh g-1 at 0.1C and a remarkable capacity retention rate of 86.5% after 100 cycles at 0.2C. And the reasons for sodium deficiency in the synthesized NFP are elucidated through first-principles calculations. Furthermore, the kinetics of the solid-solution reaction 2 (Na2/3+ßPO4→ Na1-αFePO4) mechanism improve with cycling and are sensitive to temperature. Utilizing a minimal amount of reducing agent in the electrochemical reactor, NaFePO4 synthesis is successfully achieved. This innovative approach offers a new, cost-effective, and environmentally friendly strategy for preparing NaFePO4 from recycling LiFePO4.

12.
Fitoterapia ; 175: 105965, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38631599

RESUMO

Four new diterpenoids, including three secolathyrane diterpenoids (1-3) and one lathyrane diterpenoid (4), together with seven known diterpenoids, were obtained in the shelled seeds of Euphorbia lathyris. In particular, 1-3 possess a rare split ring structure, and currently only one compound with the same skeleton has been identified in E. lathyris. Compound 4 furnishes an unprecedented oxygen bridge structure. The structures were identified using various spectral techniques, including NMR, HR-ESI-MS, single-crystal X-ray diffraction and calculated electronic circular dichroism (ECD). The biosynthetic pathway of 1-4 was inferred. Furthermore, the cytotoxic activities of all compounds (1-11) were measured on three human tumor cells. New compounds 2 and 3 showed moderate cytotoxic activities against U937 cells with IC50 values of 22.18 and 25.41 µM, respectively.

13.
Front Neurol ; 15: 1304463, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38523606

RESUMO

Background: Sleep disorders contribute to an increased risk of depression, cardiovascular issues, and various other diseases among older individuals. Consequently, enhancing the sleep quality of this demographic population has become a pressing concern. The objective of this study was to investigate the influence of an 8-week Tai Chi exercise intervention in the sleep quality of older adults. Methods: Sixty individuals aged 60 years and above, recruited from the community around Southwest University in Beibei District, Chongqing City, were randomly assigned to either a control group (30 participants) or an intervention group (30 participants). The control group adhered to their normal daily routines during the 8-week experimental period, while the intervention group engaged in a 60-min Tai Chi practice three times a week for 8 weeks. Sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), the Insomnia Severity Index (ISI), and the Epworth Sleepiness Scale (ESS). Additionally, the Polysomnographic Sleep Quality Monitoring System (PSG) was employed to monitor the sleep process before and after the Tai Chi intervention. Results: After the experiment, significant differences were observed in PSQI and IEI scores between the intervention and control groups (p < 0.05). In the experimental group, the pre-post comparisons revealed a significant increase in time spent in bed (p < 0.05), total sleep time (p < 0.05), and non-REM sleep stage 2 (p < 0.05). Conclusion: The findings indicate that Tai Chi exercise may improve subjective reported sleep quality. In addition, Tai Chi exercise may alleviate general drowsiness, extend sleep duration, and optimize the sleep process and structure. Consequently, Tai Chi exercise may be a suitable exercise to improve sleep quality in older individuals.

14.
Cell Discov ; 10(1): 33, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38531851

RESUMO

Single cell chromatin accessibility profiling and transcriptome sequencing are the most widely used technologies for single-cell genomics. Here, we present Microwell-seq3, a high-throughput and facile platform for high-sensitivity single-nucleus chromatin accessibility or full-length transcriptome profiling. The method combines a preindexing strategy and a penetrable chip-in-a-tube for single nucleus loading and DNA amplification and therefore does not require specialized equipment. We used Microwell-seq3 to profile chromatin accessibility in more than 200,000 single nuclei and the full-length transcriptome in ~50,000 nuclei from multiple adult mouse tissues. Compared with the existing polyadenylated transcript capture methods, integrative analysis of cell type-specific regulatory elements and total RNA expression uncovered comprehensive cell type heterogeneity in the brain. Gene regulatory networks based on chromatin accessibility profiling provided an improved cell type communication model. Finally, we demonstrated that Microwell-seq3 can identify malignant cells and their specific regulons in spontaneous lung tumors of aged mice. We envision a broad application of Microwell-seq3 in many areas of research.

15.
ChemSusChem ; : e202400339, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38440923

RESUMO

The pursuit of efficient host materials to address the sluggish redox kinetics of sulfur species has been a longstanding challenge in advancing the practical application of lithium-sulfur batteries. In this study, amorphous carbon layer loaded with ultrafine CoP nanoparticles prepared by a one-step in situ carbonization/phosphating method to enhance the inhibition of 2D black phosphorus (BP) on LiPSs shuttle. The carbon coating layer facilitates accelerated electron/ion transport, enabling the active involvement of BP in the conversion of soluble lithium polysulfides (LiPSs). Concurrently, the ultra-fine CoP nanoparticles enhance the chemical anchoring ability and introduce additional catalytic sites. As a result, S@BP@C-CoP electrodes demonstrate exemplary cycling stability (with a minimal capacity decay of 0.054 % over 500 cycles at 1 C) and superior rate performance (607.1 mAh g-1 at 5 C). Moreover, at a sulfur loading of 5.5 mg cm-2, the electrode maintains an impressive reversible areal capacity of 5.45 mAh cm-2 after 50 cycles at 0.1 C. This research establishes a promising approach, leveraging black phosphorus-based materials, for developing high-efficiency Li-S batteries.

16.
Int Immunopharmacol ; 131: 111861, 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38484665

RESUMO

Glutathione (GSH) depletion, mitochondrial damage, and oxidative stress have been implicated in the pathogenesis of acetaminophen (APAP) hepatotoxicity. Here, we demonstrated that the expression of histone deacetylase 6 (HDAC6) is highly elevated, whereas malate dehydrogenase 1 (MDH1) is downregulated in liver tissues and AML-12 cells induced by APAP. The therapeutic benefits of LT-630, a novel HDAC6 inhibitor on APAP-induced liver injury, were also substantiated. On this basis, we demonstrated that LT-630 improved the protein expression and acetylation level of MDH1. Furthermore, after overexpression of MDH1, an upregulated NADPH/NADP+ ratio and GSH level and decreased cell apoptosis were observed in APAP-stimulated AML-12 cells. Importantly, MDH1 siRNA clearly reversed the protection of LT-630 on APAP-stimulated AML-12 cells. In conclusion, LT-630 could ameliorate liver injury by modulating MDH1-mediated oxidative stress induced by APAP.


Assuntos
Doença Hepática Crônica Induzida por Substâncias e Drogas , Doença Hepática Induzida por Substâncias e Drogas , Desacetilase 6 de Histona , Leucemia Mieloide Aguda , Animais , Humanos , Camundongos , Acetaminofen , Doença Hepática Induzida por Substâncias e Drogas/patologia , Doença Hepática Crônica Induzida por Substâncias e Drogas/metabolismo , Glutationa/metabolismo , Desacetilase 6 de Histona/antagonistas & inibidores , Leucemia Mieloide Aguda/metabolismo , Fígado/patologia , Camundongos Endogâmicos C57BL , Estresse Oxidativo/efeitos dos fármacos
17.
Adv Sci (Weinh) ; 11(17): e2309392, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38403451

RESUMO

MXene-based thermal camouflage materials have gained increasing attention due to their low emissivity, however, the poor anti-oxidation restricts their potential applications under complex environments. Various modification methods and strategies, e.g., the addition of antioxidant molecules and fillers have been developed to overcome this, but the realization of long-term, reliable thermal camouflage using MXene network (coating) with excellent comprehensive performance remains a great challenge. Here, a MXene-based hybrid network comodified with hyaluronic acid (HA) and hyperbranched polysiloxane (HSi) molecules is designed and fabricated. Notably, the presence of appreciated HA molecules restricts the oxidation of MXene sheets without altering infrared stealth performance, superior to other water-soluble polymers; while the HSi molecules can act as efficient cross-linking agents to generate strong interactions between MXene sheets and HA molecules. The optimized MXene/HA/HSi composites exhibit excellent mechanical flexibility (folded into crane structure), good water/solvent resistance, and long-term stable thermal camouflage capability (with low infrared emissivity of ≈0.29). The long-term thermal camouflage reliability (≈8 months) under various outdoor weathers and the scalable coating capability of the MXene-coated textile enable them to disguise the IR signal of various targets in complex environments, indicating the great promise of achieved material for thermal camouflage, IR stealth, and counter surveillance.

18.
J AOAC Int ; 107(3): 471-478, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38407384

RESUMO

BACKGROUND: For pathogen detection in food, there are occasions where samples cannot be processed immediately after selective enrichment or need to be reexamined days or weeks later for confirmation or retest. OBJECTIVE: This study aimed to investigate the effect of different prolonged period of storage of selective enrichments of food at 4 ± 2°C and room temperature (20-22°C) on the detection and isolation of Salmonella. METHOD: This study included two experiments involving 34 types of foods to compare the effect of 4 ± 2°C and room temperature storage on the detection of Salmonella in 204 selective enrichments (Rappaport-Vassiliadis [RV] and Tetrathionate [TT] broths) during a 42-day storage (Experiment I); and to monitor the survival of Salmonella in 300 selective enrichments (RV and TT) with different pre-enrichment broths (Lactose broth [LB] or Buffered peptone water broth [BPW]), stored at 4°C for 60 days (Experiment II). All the samples were subjected to Salmonella analysis following the FDA BAM method. RESULTS: During multiple samplings, the positive detection rate for Salmonella remained consistent through Day 42 after selective enrichment, irrespective of Salmonella serotype, storage temperature, pre-enrichment broth, or selective enrichment broth in both Experiment I and II. However, on Day 60 sampling in Experiment II, seven previously positive results turned to negatives. These data indicated that storage of RV and TT enrichments at 4 ± 2°C or room temperature for up to 42 days after selective enrichment did not compromise the detection of Salmonella in the tested food categories, regardless of Salmonella serotypes and the broths used for pre-enrichment and selective enrichment. CONCLUSIONS: At least for the food types studied in this experiment, the recovery of Salmonella from selective enrichments could be postponed for a limited period of time (e.g., <42 days) if needed without adversely affecting the test results. However, the delayed analysis of TT and RV enrichments does pose a risk of reduced detection sensitivity, as evidenced by the seven negative results on Day 60 compared to previous positives. We do not recommend or endorse delaying the analysis of TT and RV enrichments. HIGHLIGHTS: In the food matrixes investigated in this experiment, the plating and isolation of Salmonella from selective TT and RV enrichments stored at 4 ± 2°C or room temperature could be deferred for a period (up to 42 days) without any negative effect on the test results, if necessary.


Assuntos
Microbiologia de Alimentos , Salmonella , Temperatura , Salmonella/isolamento & purificação , Microbiologia de Alimentos/métodos , Fatores de Tempo , Armazenamento de Alimentos , Contaminação de Alimentos/análise , Meios de Cultura
19.
Int J Biol Macromol ; 262(Pt 1): 130013, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38340930

RESUMO

A natural polysaccharide-based vehicle is facilely prepared for enantioselective loading of S-naproxen (S-NPX) and its programmed release. Cyclodextrin metal-organic frameworks (CD-MOF) are synthesized through the coordination of K+ with γ-cyclodextrin (γ-CD). Compared with R-NPX, the CD-MOF preferably combines with S-NPX, which can be confirmed by the thermodynamic calculations. The S-NPX loaded CD-MOF (CD-MOF-S-NPX) is grafted with disulfide bond (-S-S-) to improve its hydrophobicity, and the loaded S-NPX is further encapsulated in the chiral cavity of γ-CD by carboxymethyl potato starch (CPS) hydrogels. The intermolecular hydrogen bonding of the CPS hydrogels is prone to be destroyed in mildly basic media (∼pH 8.0), resulting in the swelling of the hydrogels; the -S-S- linkage in the vehicle can be cleaved in the presence of glutathione (GSH), leading to the collapse of the CD-MOF. Therefore, the programmed release of S-NPX can be achieved. Also in this work, the release kinetics is investigated, and the results indicate that the release of S-NPX is controlled by the Higuchi model.


Assuntos
Ciclodextrinas , Estruturas Metalorgânicas , Solanum tuberosum , Ciclodextrinas/química , Naproxeno/química , Estruturas Metalorgânicas/química , Hidrogéis , Estereoisomerismo
20.
Nat Commun ; 15(1): 1001, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38307864

RESUMO

Ar++N2 → Ar+N2+ has served as a paradigm for charge-transfer dynamics studies during the last several decades. Despite significant experimental and theoretical efforts on this model system, state-resolved experimental investigations on the microscopic charge-transfer mechanism between the spin-orbit excited Ar+(2P1/2) ion and N2 have been rare. Here, we measure the first quantum state-to-state differential cross sections for Ar++N2 → Ar+N2+ with the Ar+ ion prepared exclusively in the spin-orbit excited state 2P1/2 on a crossed-beam setup with three-dimensional velocity-map imaging. Trajectory surface-hopping calculations qualitatively reproduce the vibrationally dependent rotational and angular distributions of the N2+ product. Both the scattering images and theoretical calculations show that the charge-transfer dynamics of the spin-orbit excited Ar+(2P1/2) ion differs significantly from that of the spin-orbit ground Ar+(2P3/2) when colliding with N2. Such state-to-state information makes quantitative understanding of this benchmark charge-transfer reaction within reach.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA