Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 3.277
Filter
1.
Nat Commun ; 15(1): 2871, 2024 Apr 11.
Article in English | MEDLINE | ID: mdl-38605019

ABSTRACT

The development of van der Waals heterostructures has introduced unconventional phenomena that emerge at atomically precise interfaces. For example, interlayer excitons in two-dimensional transition metal dichalcogenides show intriguing optical properties at low temperatures. Here we report on room-temperature observation of interface excitons in mixed-dimensional heterostructures consisting of two-dimensional tungsten diselenide and one-dimensional carbon nanotubes. Bright emission peaks originating from the interface are identified, spanning a broad energy range within the telecommunication wavelengths. The effect of band alignment is investigated by systematically varying the nanotube bandgap, and we assign the new peaks to interface excitons as they only appear in type-II heterostructures. Room-temperature localization of low-energy interface excitons is indicated by extended lifetimes as well as small excitation saturation powers, and photon correlation measurements confirm antibunching. With mixed-dimensional van der Waals heterostructures where band alignment can be engineered, new opportunities for quantum photonics are envisioned.

2.
Opt Express ; 32(7): 12551-12568, 2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38571075

ABSTRACT

The physics of nonlinear optical materials is incredibly versatile, with the design of novel materials and structures offering numerous degrees of freedom. Nevertheless, weak inherent nonlinearity of conventional optical materials continues to hinder the progress of a number of important applications. In this study, we delve into the realm of broadband enhancement of nonlinearity within one-dimensional (1d) plasmonic metamaterials, exploring its intricate connection with nonlocality. Specifically, we introduce a phenomenological framework for quantifying the effective third-order nonlinear susceptibility of 1d multiphase plasmonic nanostructures, utilizing heavily doped semiconductors, and subsequently applying this approach using realistic material parameters. Both direct and inverse problems of nonlinearity enhancement have been addressed. Our findings demonstrate a remarkable capability to significantly augment the third-order nonlinear susceptibility across a defined frequency range, while concurrently gauging the impact of nonlocality on this enhancement.

3.
Front Cell Neurosci ; 18: 1363154, 2024.
Article in English | MEDLINE | ID: mdl-38590714

ABSTRACT

ADP-ribosylation plays a significant role in various biological processes including genomic stability maintenance, transcriptional regulation, energy metabolism, and cell death. Using macrodomain pull-down assay with microglia lysates and MALDI-TOF-MS analysis, we identified vimentin as a major protein highly ADP-ribosylated by the poly(ADP-ribose) polymerases-1 (PARP-1) in response to LPS. ABT-888, a potent inhibitor of PARP-1/2 blocks the disassembly and ADP-ribosylation of vimentin. PARP-1 is a highly abundant nuclear protein. Its nuclear functions in repairing DNA damages induced by various stress signals, such as inflammatory stresses, have been well studied. In contrast, limited studies have been done on the cytoplasmic role(s) of PARP-1. Our study focuses on the cytoplasmic role of PARP-1 during microglia activation. Using immunofluorescence microscopy and Western blotting, we showed that a significant amount of PARP-1 is present in the cytosol of microglia cells stimulated and activated by LPS. Live cell imaging showed the translocation of nuclear PARP-1-EGFP to the cytoplasm in vesicular structures upon LPS stimulation. ABT-888 and U0126 can block this translocation. Immunofluorescence staining with various organelle marker antibodies revealed that PARP-1 vesicles show colocalization with Lamin A/C, suggesting they might be derived from the nuclear envelope through nuclear envelope budding. In conclusion, we demonstrated that PARP-1 is translocated from the nucleus to cytoplasm via vesicles upon LPS stimulation and that cytoplasmic PARP-1 causes ADP-ribosylation and disassembly of vimentin filaments during microglia activation induced by LPS.

4.
J Physiol Pharmacol ; 75(1)2024 02.
Article in English | MEDLINE | ID: mdl-38583440

ABSTRACT

This study was designed to examine the anti-oxidative stress effect of dimethyl fumarate (DMF) on pentylenetetrazole (PTZ)-induced epileptic mice, and to evaluate the correlation of its mechanism with the nuclear factor E2-related factor 2 (Nrf2)-mediated signaling pathway. The experimental mice were separated into three groups: control, model, and DMF groups. Mice in the model group were administered PTZ to establish an epilepsy model, mice in the DMF group were administered DMF concurrently when modeling, and mice in the control group were administered a 0.9% NaCl solution. The latency, severity, and frequency of epileptic seizures in mice after each treatment were recorded, and the modelling success rate was computed at the conclusion of the experiment. The mice were euthanized, their levels of malondialdehyde (MDA), reactive oxygen species (ROS), superoxide dismutase (SOD), 8-hydroxy-deoxyguanosine (8-OHdG), and Nrf2 were measured, and the electron microscope was used to examine the mitochondrial damage of brain tissue. The latency of epileptic seizures was longer in the DMF group compared to the model group (P<0.05). The levels of MDA and ROS in the DMF group were lower than those in the model group (P<0.0001), and the activity of SOD in the DMF group was higher than that in the model group (P<0.0001); however, the levels of MDA and ROS were elevated and the activity of SOD was lower in both groups relative to the control group. The levels of 8-OHdG were lower in the DMF group than the model group (P<0.0001), however, the levels were higher in both groups compared to the control group. Mitochondrial abnormalities were more prevalent in the model group than in the DMF group, and more prevalent in both groups compared to the control group. The DMF group contained more Nrf2 content than the model group (P<0.0001), and both groups contained more Nrf2 than the control group. We concluded that the mechanism by which DMF reduced the level of oxidative stress in epileptic mice might involve the Nrf2-mediated signaling pathway.


Subject(s)
Dimethyl Fumarate , Epilepsy , Animals , Mice , Antioxidants/pharmacology , Antioxidants/metabolism , Dimethyl Fumarate/pharmacology , Dimethyl Fumarate/therapeutic use , Epilepsy/chemically induced , Epilepsy/drug therapy , NF-E2-Related Factor 2/metabolism , Oxidative Stress , Pentylenetetrazole/pharmacology , Reactive Oxygen Species/metabolism , Seizures/chemically induced , Seizures/drug therapy , Superoxide Dismutase/metabolism
5.
Zhonghua Yi Xue Za Zhi ; 104(11): 843-849, 2024 Mar 19.
Article in Chinese | MEDLINE | ID: mdl-38462360

ABSTRACT

Objective: To investigate the effects of sirolimus combined with anti-CD20 monoclonal antibody desensitization on the prognosis of patients with haploidentical stem cell transplantation (haplo-SCT). Methods: Fifteen consecutive patients who received haplo-SCT and pre-transplant donor specific anti-human leukocyte antigen (HLA) antibody (DSA) positive [mean fluorescence intensity (MFI)≥2 000] in the Institute of Hematological Diseases from November 2021 to March 2023 were retrospectively recruited into the desensitized group. There were 4 males and 11 females, with a median age [M(Q1, Q3)] of 48 (37, 59) years. All patients were desensitized with sirolimus combined with anti-CD20 monoclonal antibody. The non-desensitized group included 29 patients with haplo-SCT who had not received desensitization treatment from August 2012 to June 2016. There were 12 males and 17 females with a median age of 42 (26, 50) years. Up to October 1, 2023, the median follow-up time was 13 (9, 18) months in the study group and 23 (14, 29) months in the control group. The changes of MFI before and after desensitization treatment and the prognosis of patients in the desensitized group were compared, including the incidence of primary implantation failure (pGF), neutrophil implantation time, platelet implantation time, grade Ⅱ-Ⅳ acute graft-versus-host disease (GVHD) and chronic GVHD incidence, non-recurrence related mortality, event-free survival rate, disease-free survival rate and overall survival rate. The survival curve was drawn by Kaplan-Meier method, and the survival rate between groups was compared with Log-rank test. Results: After desensitization treatment, the level of DSA MFI in the desensitized group decreased from 8 879 (7 544, 11 495) to 3 781 (1 638, 4 165) after desensitization treatment (P<0.01). All of the patients achieved hematopoietic recovery, and the median time for neutrophil and platelet engraftment were 14 (11, 15) and 20 (18, 25) days, respectively. The incidence of pGF in the desensitized group was 0, which was lower than that in the non-desensitized group (34.5%, 10/29) (P=0.011). The expected 1-year disease-free survival rate and overall survival rate in the desensitized group were 100% (15/15) and 100% (15/15) respectively, while those in the non-desensitized group were 75.9% (22/29) and 75.9% (22/29) respectively, the difference was not statistically significant (both P>0.05). The one-year event-free survival rate in the desensitized group was expected to be 100% (15/15), which was higher than that in the non-desensitized group (51.3%, 15/29) (P=0.002). Conclusion: Sirolimus combined with anti-CD20 monoclonal antibody desensitization therapy can reduce the DSA level of haplo-SCT recipients, promote hematopoietic engraftment after transplantation, and avoid the occurrence of pGF after transplantation.


Subject(s)
Graft vs Host Disease , Hematopoietic Stem Cell Transplantation , Male , Female , Humans , Sirolimus/therapeutic use , Retrospective Studies , Hematopoietic Stem Cell Transplantation/adverse effects , Prognosis , Graft vs Host Disease/etiology , Antibodies, Monoclonal , Transplantation Conditioning/adverse effects , Transplantation Conditioning/methods
7.
Zhonghua Wai Ke Za Zhi ; 62(5): 393-399, 2024 May 01.
Article in Chinese | MEDLINE | ID: mdl-38548607

ABSTRACT

Objective: To examine the early to mid-term clinical outcomes of aortic valve repair in patients with bicuspid aortic insufficiency. Methods: This is a retrospective cohort study. The clinical data of 124 patients with BAV insufficiency who underwent aortic valve repair from January 2017 to June 2023 in the Department of Cardiovascular Surgery at Fuwai Hospital were analyzed retrospectively. There were 117 males and 7 females with an age of (38.1±12.7) years (range: 14 to 65 years). Depending on whether the aortic sinus was replaced or not, surgical approaches were divided into valve sparing root replacement (reimplantation, remodeling, modified remodeling) and isolated aortic valve repair (annuloplasty, isolated aortic valve leaflet repair). Perioperative and follow-up data were collected. Kaplan-Meier method was used to plot the curves of survival rate, free recurrence rate of massive aortic valve insufficiency and free re-operation rate, and Log-rank test was used for comparison between groups. Results: Among the surgeries, there were 47 cases of reimplantation, 8 cases of remodeling, 8 cases of modified remodeling, 48 cases of aortic annuloplasty (external annuloplasty in 22 cases, CV-0 annuloplasty in 26 cases), and 13 cases of isolated leaflet repair. Leaflet plication was the most used leaflet repair technique, used in 103 patients. The cardiopulmonary bypass time was (133.7±56.9) minutes (range: 48 to 461 minutes), and aortic cross-clamp time was (103.8±47.8) minutes (range: 25 to 306 minutes), with no surgical mortality. All patients underwent outpatient or telephone follow-up. The cumulative follow-up time was 340.3 person-years and the mean follow-up time was (M (IQR)) 34.0 (25.5) months (range: 3 to 76 months). The 5-year survival rate was 98.4%, the 5-year freedom from significant insufficiency rate was 93.4% and the 5-year freedom from aortic valve reoperation rate was 95.6%. The subgroup analysis revealed a significantly better freedom from the significant insufficiency rate in the aortic valve annular reduction group compared to the non-reduction group (P<0.01). Conclusions: Aortic valve repair in patients with bicuspid aortic insufficiency could obtain steady early to mid-term outcomes. Aortic annuloplasty can reduce the risk of recurrent aortic valve insufficiency in patients undergoing aortic repair.


Subject(s)
Aortic Valve Insufficiency , Aortic Valve , Bicuspid Aortic Valve Disease , Humans , Male , Female , Adult , Retrospective Studies , Middle Aged , Bicuspid Aortic Valve Disease/surgery , Aortic Valve Insufficiency/surgery , Aortic Valve/surgery , Aortic Valve/abnormalities , Adolescent , Young Adult , Treatment Outcome , Aged , Heart Valve Diseases/surgery , Cardiac Valve Annuloplasty/methods , Survival Rate
8.
Anticancer Res ; 44(3): 1121-1130, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38423629

ABSTRACT

BACKGROUND/AIM: Chronic lymphocytic leukemia is a slowly-progressing disease in which symptoms often do not manifest until years after disease onset. In advanced stages, infection and bleeding are common. Past studies have shown that the interaction between CDK4/6 inhibitors and chemotherapy drugs can enhance the anti-tumor efficacy of drugs and limit toxicity. Therefore, in this study, the treatment effects of combining the CDK4/6 inhibitor LEE011 with chemotherapy drugs bendamustine or hydroxyurea were investigated in vitro. MATERIALS AND METHODS: The mouse lymphocytic leukemia cell line L1210 was treated with LEE011 combined with hydroxyurea or bendamustine. Western blot and flow cytometry were performed to elucidate the mechanisms behind tumor suppression. RESULTS: LEE011 combined with hydroxyurea or bendamustine significantly inhibited proliferation of L1210 cell lines in a concentration- and time-dependent manner as well as increased the arrest of cells in G1 and S phases. The combination of LEE011 with hydroxyurea also reduced the phosphorylation of Rb while increased the expression of total Rb protein. Furthermore, reduced expression of GPX4, which is a key protein in ferroptosis, indicates that the tumor suppression effects of this drug combination could involve ferroptosis. CONCLUSION: CDK4/6 inhibitor LEE011 treatment alone may not be a suitable treatment option for lymphocytic leukemia; however, our findings in vitro support the combination of LEE011 with chemotherapy drugs to enhance anti-tumor activity in lymphocytic leukemia.


Subject(s)
Aminopyridines , Hydroxyurea , Neoplasms , Purines , Animals , Mice , Cell Proliferation , Hydroxyurea/pharmacology , Bendamustine Hydrochloride , Cyclin-Dependent Kinase Inhibitor Proteins , Cyclin-Dependent Kinase 4 , Cell Line, Tumor
9.
Occup Med (Lond) ; 74(2): 152-160, 2024 Apr 03.
Article in English | MEDLINE | ID: mdl-38330390

ABSTRACT

BACKGROUND: Irregular menstruation is a major health problem among women, although its association with nightshift work remains controversial. AIMS: To study the association between nightshift work and irregular menstrual cycle among female workers and investigate any differences according to sleep quality, working hours or obesity. METHODS: This study included female workers who underwent health examinations from 2012 to 2019. Nightshift work, working hours, sleep quality and menstrual cycles were assessed using self-administered questionnaires. Irregular menstrual cycle was defined as self-reported irregular or ≥36 days. Adjusted odds ratios and 95% confidence intervals (CIs) were calculated by multivariable logistic regression; adjusted hazard ratios (95% CIs) for incident irregular menstrual cycle were calculated by Cox proportional hazard models with time-dependent analysis. RESULTS: The study participants were 87 147 in the cross-sectional study and 41 516 in the longitudinal study. After adjusting for all covariates in the cross-sectional analyses, the odds ratio for prevalent irregular menstrual cycle among female nightshift workers versus the reference was 1.26 (95% CI 1.2-1.33). In the cohort study, the adjusted hazard ratio for incident irregular menstrual cycle among nightshift workers was 1.95 (95% CI 1.61-2.35) in the period after 6 years. No significant differences were observed among subgroups stratified by sleep quality, working hours or obesity. CONCLUSIONS: Nightshift work is associated with an increased risk of both prevalent and incident irregular menstrual cycle in female workers without significant interactions by sleep quality, working hours or obesity.


Subject(s)
Menstrual Cycle , Menstruation Disturbances , Female , Humans , Follow-Up Studies , Cohort Studies , Cross-Sectional Studies , Longitudinal Studies , Menstruation Disturbances/etiology , Menstruation Disturbances/complications , Obesity/epidemiology , Obesity/complications
10.
Langmuir ; 2024 Feb 08.
Article in English | MEDLINE | ID: mdl-38329924

ABSTRACT

The search for high-performance catalysts to improve the catalytic activity for an oxygen reduction reaction (ORR) is crucial for developing a proton exchange membrane fuel cell. Using the first-principles method, we have performed computational screening on a series of transition metal (TM) atoms embedded in monolayer Nb2S2C to enhance the ORR activity. Through the scaling relationship and volcano plot, our results reveal that the introduction of a single Ni or Rh atom through substitutional doping into monolayer Nb2S2C yields promising ORR catalysts with low overpotentials of 0.52 and 0.42 V, respectively. These doped atoms remain intact on the monolayer Nb2S2C even at elevated temperatures. Importantly, the catalytic activity of the Nb2S2C doped with a TM atom can be effectively correlated with an intrinsic descriptor, which can be computed based on the number of d orbital electrons and the electronegativity of TM and O atoms.

11.
Article in English | MEDLINE | ID: mdl-38278686

ABSTRACT

The autogenous bone ring technique is among the approaches for vertical alveolar ridge augmentation, and this technique can enable simultaneous implantation. However, the outcomes can be compromised due to donor site morbidity, shifting of the bone ring graft positioning, and inaccurate implant placement. In recent decades, dynamic navigation systems have been introduced into the field of implantology, allowing the accuracy of outcomes to be improved. This Technical Note describes the use of dynamic navigation to guide bone ring surgery, which is expected to enable more precise and predictable bone augmentation and implantation procedures, reduce the risk of injuries to the adjacent anatomical structures, and achieve better treatment outcomes.

12.
Phytopathology ; 114(2): 378-392, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37606348

ABSTRACT

Disease severity in plant pathology is often measured by the amount of a plant or plant part that exhibits disease symptoms. This is typically assessed using a numerical scale, which allows a standardized, convenient, and quick method of rating. These scales, known as quantitative ordinal scales (QOS), divide the percentage scale into a predetermined number of intervals. There are various ways to analyze these ordinal data, with traditional methods involving the use of midpoint conversion to represent the interval. However, this may not be precise enough, as it is only an estimate of the true value. In this case, the data may be considered interval-censored, meaning that we have some knowledge of the value but not an exact measurement. This type of uncertainty is known as censoring, and techniques that address censoring, such as survival analysis (SA), use all available information and account for this uncertainty. To investigate the pros and cons of using SA with QOS measurements, we conducted a simulation based on three pathosystems. The results showed that SA almost always outperformed midpoint conversion with data analyzed using a t test, particularly when data were not normally distributed. Midpoint conversion is currently a standard procedure. In certain cases, the midpoint approach required a 400% increase in sample size to achieve the same power as the SA method. However, as the mean severity increases, fewer additional samples are needed (approximately an additional 100%), regardless of the assessment method used. Based on these findings, we conclude that SA is a valuable method for enhancing the power of hypothesis testing when analyzing QOS severity data. Future research should investigate the wider use of survival analysis techniques in plant pathology and their potential applications in the discipline.


Subject(s)
Plant Diseases , Plant Pathology , Computer Simulation , Patient Acuity , Survival Analysis
14.
J Sci Med Sport ; 27(1): 16-19, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37923648

ABSTRACT

Para swimmers with limb deficiency are faced with the particular situation that they must use their head to finish each competition by a hit to the wall. Repetitive head impacts may impair behavioral and brain functions. We therefore investigated neurobehavioral functions of a Para swimmer with dysmelia before and after repetitive head impacts (T1) and without (T2). Average head impact at T1 constituted 13.6 g with a mean impact force of 6689.9 N. Behavioral and brain functions decreased from pre to post at T1 but not at T2. Para swimmers with limb deficiency are therefore affected from the same consequences onto brain health that are observed after repeated sport-related concussions.


Subject(s)
Brain Concussion , Swimming , Humans , Brain Concussion/complications
15.
Nat Commun ; 14(1): 8152, 2023 Dec 09.
Article in English | MEDLINE | ID: mdl-38071345

ABSTRACT

Nanomaterials exhibit unique optical phenomena, in particular excitonic quantum processes occurring at room temperature. The low dimensionality, however, imposes strict requirements for conventional optical excitation, and an approach for bypassing such restrictions is desirable. Here we report on exciton transfer in carbon-nanotube/tungsten-diselenide heterostructures, where band alignment can be systematically varied. The mixed-dimensional heterostructures display a pronounced exciton reservoir effect where the longer-lifetime excitons within the two-dimensional semiconductor are funneled into carbon nanotubes through diffusion. This new excitation pathway presents several advantages, including larger absorption areas, broadband spectral response, and polarization-independent efficiency. When band alignment is resonant, we observe substantially more efficient excitation via tungsten diselenide compared to direct excitation of the nanotube. We further demonstrate simultaneous bright emission from an array of carbon nanotubes with varied chiralities and orientations. Our findings show the potential of mixed-dimensional heterostructures and band alignment engineering for energy harvesting and quantum applications through exciton manipulation.

16.
Braz J Biol ; 83: e275635, 2023.
Article in English | MEDLINE | ID: mdl-38126635

ABSTRACT

Bioavailability of nutrients, the scarcity of synthetic fertilisers, and the rising cost of fuel have all contributed to an increase in production costs, which has in turn reduced crop productivity and led scientists to seek out new methods to ensure high-quality output. In this context, various cytokinins dosages were tested in Peru to see whether they affected the quality of caigua, in an effort to address these issues. To mitigate these problems, a pot experiment was carried out to check the effects of various doses of cytokinin in the quality of caigua in Peru. The experiment consisted of 5 treatments including (0, 50, 100, 150 and 200 mL of cytokinin) by using (Anthesis Plus per 200 L of water) as a source, each with three replicates and placed following a randomized complete block design (RCBD). Treatment with 100 mL of cytokinins foliar analysis resulted in a caigua length of 18.9 cm, an increase in diameter of 5.65 cm, and an improvement in pulp thickness of 7.60 millimeters. Physiological parameters of caigua plants taken after 45 days of sowing were considerably improved with the same treatment. Similarly, N, K and Zn concentration in leaf was higher in case of 100 mL of cytokinins foliar analysis. Therefore, policymakers must advise using the recommended quantity of cytokinins to bring about regime transition, and formers can gain by injecting 100 mL of cytokinins to boost production and the economy. It was concluded that the adequate dose of cytokinins is in treatment T3, which raised value of potassium concentration in leaves, this influenced optimal development, strengthening against environmental stress and therefore quality. For this reason, research was carried out on the comparative study of cytokinin doses in the quality of caigua in Peru; the objective was to determine the appropriate dose to obtain higher quality fruit. Likewise, it was underlined that the objective was to employ an ecological alternative of plant origin such as the usage of phytohormone that stimulates the growth of the plant and consequently the quality of the fruit. The obtained the results were served as a recommendation for farmers in the area.


Subject(s)
Cytokinins , Plant Growth Regulators , Cytokinins/pharmacology , Peru , Plant Growth Regulators/pharmacology , Plant Leaves/physiology , Stress, Physiological
17.
Braz J Biol ; 83: e275698, 2023.
Article in English | MEDLINE | ID: mdl-37937631

ABSTRACT

The pandemic and the geopolitical conflict between Russia and Ukraine are events that have caused economic instability in Peru. Reason that was investigated on the analysis of the biological and chemical characteristics of cabbage fed with compost based on sugarcane residues. The objective was to analyze the physical, chemical and biological characteristics of cabbage from the adequate dose of compost based on sugarcane residues and distance between plants. It is based on the methodology applied with an experimental approach, for which the Completely Random Block Design with a 4x 2 factorial arrangement was used, which consisted of 3 blocks and 8 treatments that were the combination: F1 with 0, F2 with 8, T3 with 10 and F4 with 12 t/ha and spacing (D1) with 0.30 m between plants and 0.60 m between rows and (D2) with 0.35 m between plants and 0.60 m between rows. The physical characteristics of cabbage were evaluated and processed by analysis of variance, nutrient concentrations in leaves and stomatal density were analyzed. The results determined that T7 stood out in plant height with 41.88 cm, yield with 26.76 tn/ha and T6 in root length with 20.22 cm. In chemical analysis of leaves T1 stood out in nitrogen, phosphorus, potassium and T4 in calcium, magnesium and sulfur. In T7 stomata density with 977 stomata/mm2. It concludes that at an adequate dose and greater distance that T7 stands out in the concentration of nutrients that are within normal values and high density of stomata; Therefore, these characteristics influenced the optimal biochemical reactions, which obtained good development and yield that differed at 51.39% and 32.17% with respect to the controls T1 and T5.


Subject(s)
Brassica , Composting , Saccharum , Brassica/chemistry , Russia
18.
Phys Rev Lett ; 131(15): 151002, 2023 Oct 13.
Article in English | MEDLINE | ID: mdl-37897756

ABSTRACT

We present the precision measurements of 11 years of daily cosmic positron fluxes in the rigidity range from 1.00 to 41.9 GV based on 3.4×10^{6} positrons collected with the Alpha Magnetic Spectrometer (AMS) aboard the International Space Station. The positron fluxes show distinctly different time variations from the electron fluxes at short and long timescales. A hysteresis between the electron fluxes and the positron fluxes is observed with a significance greater than 5σ at rigidities below 8.5 GV. On the contrary, the positron fluxes and the proton fluxes show similar time variation. Remarkably, we found that positron fluxes are modulated more than proton fluxes with a significance greater than 5σ for rigidities below 7 GV. These continuous daily positron fluxes, together with AMS daily electron, proton, and helium fluxes over an 11-year solar cycle, provide unique input to the understanding of both the charge-sign and mass dependencies of cosmic rays in the heliosphere.

19.
mBio ; 14(5): e0212323, 2023 Oct 31.
Article in English | MEDLINE | ID: mdl-37800917

ABSTRACT

IMPORTANCE: Cryptococcosis studies often utilize the common C57BL/6J mouse model. Unfortunately, infection in these mice fails to replicate the basic course of human disease, particularly hampering immunological studies. This work demonstrates that SJL/J mice can recapitulate human infection better than other mouse strains. The immunological response to Cryptococcus infection in SJL/J mice was markedly different from C57BL/6J and much more productive in combating this infection. Characterization of infected mice demonstrated strain-specific genetic linkage and differential regulation of multiple important immune-relevant genes in response to Cryptococcus infection. While our results validate many of the previously identified immunological features of cryptococcosis, we also demonstrate limitations from previous mouse models as they may be less translatable to human disease. We concluded that SJL/J mice more faithfully recapitulate human cryptococcosis serving as an exciting new animal model for immunological and genetic studies.


Subject(s)
Cryptococcosis , Cryptococcus neoformans , Humans , Mice , Animals , Cryptococcus neoformans/genetics , Mice, Inbred C57BL , Disease Models, Animal
20.
bioRxiv ; 2023 Sep 13.
Article in English | MEDLINE | ID: mdl-37745319

ABSTRACT

Changes in daylight amount (photoperiod) drive pronounced alterations in physiology and behaviour1,2. Adaptive responses to seasonal photoperiods are vital to all organisms - dysregulation is associated with disease, from affective disorders3 to metabolic syndromes4. Circadian rhythm circuitry has been implicated5,6 yet little is known about the precise neural and cellular substrates that underlie phase synchronization to photoperiod change. Here we present a previously unknown brain circuit and novel system of axon branch-specific and reversible neurotransmitter deployment that together prove critical for behavioural and sleep adaptation to photoperiod change. We found that the recently defined neuron type called mrEn1-Pet17 located in the mouse brainstem Median Raphe Nucleus (MRN) segregates serotonin versus VGLUT3 (here proxy for the neurotransmitter glutamate) to different axonal branches innervating specific brain regions involved in circadian rhythm and sleep/wake timing8,9. We found that whether measured during the light or dark phase of the day this branch-specific neurotransmitter deployment in mrEn1-Pet1 neurons was indistinguishable; however, it strikingly reorganizes on photoperiod change. Specifically, axonal boutons but not cell soma show a shift in neurochemical phenotype upon change away from equinox light/dark conditions that reverses upon return to equinox. When we genetically disabled the deployment of VGLUT3 in mrEn1-Pet1 neurons, we found that sleep/wake periods and voluntary activity failed to synchronize to the new photoperiod or was significantly delayed. Combining intersectional rabies virus tracing and projection-specific neuronal silencing in vivo, we delineated a Preoptic Area-to-mrEn1Pet1 connection responsible for decoding the photoperiodic inputs, driving the neurochemical shift and promoting behavioural synchronization. Our results reveal a previously unrecognized brain circuit along with a novel form of periodic, branch-specific neurotransmitter deployment that together regulate organismal adaptation to photoperiod changes.

SELECTION OF CITATIONS
SEARCH DETAIL
...