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1.
Commun Chem ; 7(1): 73, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38565709

RESUMO

Post-synthetic surgical editing enables synthesizing diverse molecules from a common scaffold. Editing carbohydrates by inserting a foreign glycan is still a far-reaching goal for synthetic chemists. In this study, a one-pot-three-step chemical approach was employed to edit glycoconjugates. It is comprised of three steps: the first is a 'cut' step, cleaving one of the interglycosidic bonds and producing an intermediate that could be intercepted with 4-mercaptotoluene; second step activates the thiotolyl glycoside in the presence of an aglycon containing an orthogonally activatable ethynylcycloxyl carbonate moiety; and the third step involves 'stitching' by activating the carbonate donor. The cut-insert stitch-editing reaction (CIStER) is demonstrated by inserting branched and linear arabinans reminiscent of M. tuberculosis cell wall from the same designer trimannoside. Glycosylating an activated hydroxyacid (serinyl, steroidal, and lipid) after cutting the interglycosidic bond and stitching in the presence of base extendes the CIStER approach to the synthesis of glycohybrids.

2.
Addict Sci Clin Pract ; 19(1): 16, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38491559

RESUMO

BACKGROUND: The feasibility of precision smoking treatment in socioeconomically disadvantaged communities has not been studied. METHODS: Participants in the Southern Community Cohort Study who smoked daily were invited to join a pilot randomized controlled trial of three smoking cessation interventions: guideline-based care (GBC), GBC plus nicotine metabolism-informed care (MIC), and GBC plus counseling guided by a polygenic risk score (PRS) for lung cancer. Feasibility was assessed by rates of study enrollment, engagement, and retention, targeting > 70% for each. Using logistic regression, we also assessed whether feasibility varied by age, sex, race, income, education, and attitudes toward precision smoking treatment. RESULTS: Of 92 eligible individuals (79.3% Black; 68.2% with household income < $15,000), 67 (72.8%; 95% CI 63.0-80.9%) enrolled and were randomized. Of these, 58 (86.6%; 95% CI 76.4-92.8%) engaged with the intervention, and of these engaged participants, 43 (74.1%; 95% CI 61.6-83.7%) were retained at 6-month follow-up. Conditional on enrollment, older age was associated with lower engagement (OR 0.83, 95% CI 0.73-0.95, p = 0.008). Conditional on engagement, retention was significantly lower in the PRS arm than in the GBC arm (OR 0.18, 95% CI 0.03-1.00, p = 0.050). No other selection effects were observed. CONCLUSIONS: Genetically informed precision smoking cessation interventions are feasible in socioeconomically disadvantaged communities, exhibiting high enrollment, engagement, and retention irrespective of race, sex, income, education, or attitudes toward precision smoking treatment. Future smoking cessation interventions in this population should take steps to engage older people and to sustain participation in interventions that include genetic risk counseling. TRIAL REGISTRATION: ClinicalTrials.gov No. NCT03521141, Registered 27 April 2018, https://www. CLINICALTRIALS: gov/study/NCT03521141.


Assuntos
Fumar , Fumar Tabaco , Idoso , Humanos , Estudos de Coortes , Estudos de Viabilidade , Projetos Piloto , Fumar/epidemiologia , Fumar/terapia , Masculino , Feminino
3.
bioRxiv ; 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-38496604

RESUMO

Previous studies demonstrated that Leptospira biflexa, a saprophytic species, triggers innate immune responses in the host during early infection. This raised the question of whether these responses could suppress a subsequent challenge with pathogenic Leptospira. We inoculated male C3H/HeJ mice with a single or a double dose of L. biflexa before challenge with a pathogenic serovar, L. interrogans ser. Copenhageni FioCruz (LIC). Pre-challenge exposure to L. biflexa did not prevent LIC dissemination and colonization of the kidney. However, it rescued weight loss and mouse survival thereby mitigating disease severity. Unexpectedly, there was correlation between rescue of overall health (weight gain, higher survival, lower kidney fibrosis) and higher shedding of LIC in urine. This stood in stark contrast to the L. biflexa unexposed LIC challenged control. Immune responses were dominated by increased frequency of B cells and effector T helper (CD4+) cells in spleen, as well as significant increases in serologic IgG2a. Our findings suggest that exposure to live saprophytic Leptospira primes the host to develop Th1 biased immune responses that prevent severe disease induced by a subsequent challenge with a pathogenic species. Thus, hosts exposed to live saprophytic Leptospira before challenge with a pathogenic serovar may withstand LIC infection with far better outcomes. Furthermore, a status of homeostasis may have been reached after kidney colonization that helps LIC complete its enzootic cycle.

4.
NPJ Vaccines ; 9(1): 33, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38360853

RESUMO

Strategies for disease control are necessary to reduce incidence of Lyme Disease (LD) including development of safe vaccines for human use. Parainfluenza virus 5 (PIV5) vector has an excellent safety record in animals and PIV5-vectored vaccines are currently under clinical development. We constructed PIV5-vectored LD vaccine candidates expressing OspA from B. burgdorferi (OspAB31) and a chimeric protein containing sequences from B. burgdorferi and B. afzelii (OspABPBPk). Immunogenicity and vaccine efficacy were analyzed in C3H-HeN mice after prime-boost intranasal vaccination with live PIV5-OspAB31 or PIV5-OspABPBPk, subcutaneous (s.c.) vaccination with rOspAB31+Alum, and the respective controls. Mice vaccinated intranasally with live PIV5-AB31 or PIV5-ABPBPk had higher endpoint titers of serum antibody against OspAB31 at 6- and 12- months post vaccination, compared to mice vaccinated s.c. with rOspAB31. Neutralization activity of antibody was maintained up to 18-months post-immunization, with the response greater in live PIV5-delivered OspA vaccines, than that induced by s.c. rOspAB31. Challenge with infected ticks carrying 10-19 strains of B. burgdorferi performed at 4-, 9- or 15-months post-immunization showed increased breakthrough infections in mice vaccinated with s.c. rOspAB31 compared to intranasal PIV5-AB31 or PIV5-ABPBPk at 9- and 15-months, as determined by quantification of serologic antibodies to B. burgdorferi proteins as well as flaB DNA in tissues, and by visualization of motile B. burgdorferi in culture of tissues under dark field microscope. These findings indicate that immunization of mice with PIV5 delivered OspA generates immune responses that produce longer-lasting protection ( > 1 year) against tick-transmitted B. burgdorferi than a parenteral recombinant OspA vaccine.

5.
Nat Commun ; 15(1): 45, 2024 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-38167725

RESUMO

Dietary polyunsaturated fatty acids (PUFA) are increasingly recognized for their health benefits, whereas a high production of endogenous fatty acids - a process called de novo lipogenesis (DNL) - is closely linked to metabolic diseases. Determinants of PUFA incorporation into complex lipids are insufficiently understood and may influence the onset and progression of metabolic diseases. Here we show that fatty acid synthase (FASN), the key enzyme of DNL, critically determines the use of dietary PUFA in mice and humans. Moreover, the combination of FASN inhibition and PUFA-supplementation decreases liver triacylglycerols (TAG) in mice fed with high-fat diet. Mechanistically, FASN inhibition causes higher PUFA uptake via the lysophosphatidylcholine transporter MFSD2A, and a diacylglycerol O-acyltransferase 2 (DGAT2)-dependent incorporation of PUFA into TAG. Overall, the outcome of PUFA supplementation may depend on the degree of endogenous DNL and combining PUFA supplementation and FASN inhibition might be a promising approach to target metabolic disease.


Assuntos
Ácidos Graxos Ômega-3 , Doenças Metabólicas , Camundongos , Humanos , Animais , Lipogênese , Ácidos Graxos Ômega-3/farmacologia , Ácidos Graxos Ômega-3/metabolismo , Ácidos Graxos Insaturados , Triglicerídeos/metabolismo , Ácidos Graxos , Dieta Hiperlipídica/efeitos adversos
6.
Artigo em Inglês | MEDLINE | ID: mdl-37975291

RESUMO

Significance: Sickle cell disease (SCD) is the most common inherited diathesis affecting mostly underserved populations globally. SCD is characterized by chronic pain and fatigue, severe acute painful crises requiring hospitalization and opioids, strokes, multiorgan damage, and a shortened life span. Symptoms may appear shortly after birth, and, in less developed countries, most children with SCD die before attaining age 5. Hematopoietic stem cell transplant and gene therapy offer a curative therapeutic approach, but, due to many challenges, are limited in their availability and effectiveness for a majority of persons with SCD. A critical unmet need is to develop safe and effective novel targeted therapies. A wide array of drugs currently undergoing clinical investigation hold promise for an expanded pharmacological armamentarium against SCD. Recent Advances: Hydroxyurea, the most widely used intervention for SCD management, has improved the survival in the Western world and more recently, voxelotor (R-state-stabilizer), l-glutamine, and crizanlizumab (anti-P-selectin antibody) have been approved by the Food and Drug Administration (FDA) for use in SCD. The recent FDA approval emphasizes the need to revisit the advances in understanding the core pathophysiology of SCD to accelerate novel evidence-based strategies to treat SCD. The biomechanical breakdown of erythrocytesis, the core pathophysiology of SCD, is associated with intrinsic factors, including the composition of hemoglobin, membrane integrity, cellular volume, hydration, andoxidative stress. Critical Issues and Future Directions: In this context, this review focuses on advances in emerging nongenetic interventions directed toward the therapeutic targets intrinsic to sickle red blood cells (RBCs), which can prevent impaired rheology of RBCs to impede disease progression and reduce the sequelae of comorbidities, including pain, vasculopathy, and organ damage. In addition, given the intricate pathophysiology of the disease, it is unlikely that a single pharmacotherapeutic intervention will comprehensively ameliorate the multifaceted complications associated with SCD. However, the availability of multiple drug options affords the opportunity for individualized therapeutic regimens tailored to specific SCD-related complications. Furthermore, it opens avenues for combination drug therapy, capitalizing on distinct mechanisms of action and profiles of adverse effects.

7.
Int J Biol Macromol ; 254(Pt 2): 127898, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37939768

RESUMO

The ADP ribosylation factor like protein 15 (ARL15) gene encodes for an uncharacterized GTPase associated with rheumatoid arthritis (RA) and other metabolic disorders. Investigation of the structural and functional attributes of ARL15 is important to position the protein as a potential drug target. Using spectroscopy, we demonstrated that ARL15 exhibits properties inherent of GTPases. The Km and Vmax of the enzyme were calculated to be 100 µM and 1.47 µmole/min/µL, respectively. The equilibrium dissociation constant (Kd) of GTP binding with ARL15 was estimated to be about eight-fold higher than that of GDP. Small Angle X-ray Scattering (SAXS) data indicated that in solution, the apo state of monomeric ARL15 adopts a shape characterized by a globe of maximum linear dimension (Dmax) of 6.1 nm, and upon binding to GTP or GDP, the vector distribution profile changes to peak-n-tail shoulder with Dmax extended to 7.6 and 7.7 nm, respectively. Structure restoration using a sequence-based template and experimental SAXS data provided the first visual insight revealing that the folded N-terminal in the unbound state of the protein may toggle open upon binding to guanine nucleotides. The conformational dynamics observed in the N-terminal region offer a scope to develop drugs that target this unique GTPase, potentially providing treatments for a range of metabolic disorders.


Assuntos
Artrite Reumatoide , Doenças Metabólicas , Humanos , Nucleotídeos de Guanina , Nucleotídeos/metabolismo , Guanina , Espalhamento a Baixo Ângulo , Difração de Raios X , Fatores de Ribosilação do ADP/genética , Fatores de Ribosilação do ADP/metabolismo , Proteínas/metabolismo , Guanosina Trifosfato/metabolismo , Guanosina Difosfato
8.
Curr Protein Pept Sci ; 25(2): 137-153, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37718516

RESUMO

ARL15 is a member of the RAS superfamily of small GTPases and is associated with several metabolic traits, including increased risk of diabetes, rheumatoid arthritis and lipid metabolism disorders. The ARL15 gene encodes for an uncharacterized small GTP binding protein. Its precise role in human physiology remains unknown, but several genetic association studies have recognized different variants in this gene to be statistically associated with numerous traits and complex diseases. Here, we provided the unique features of ARL15 small G protein, its association with varied metabolic and lifestyle diseases, its function in vesicular and lipid trafficking, and its binding partners. We outlined this protein as a promising and emerging therapeutic target to combat metabolic disorders like cardiovascular diseases, diabetes and rheumatoid arthritis. The review provides a comprehensive description of the current advancements in ARL15 research with a perspective that focused research will position this small GTPase as a viable target for the treatment of rheumatoid arthritis.


Assuntos
Artrite Reumatoide , Diabetes Mellitus , Humanos , Fatores de Ribosilação do ADP/genética , Fatores de Ribosilação do ADP/metabolismo , Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/genética , Estudos de Associação Genética , Fenótipo
9.
J Pain ; 2023 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-38029949

RESUMO

Opioid prescribing remains common despite known overdose-related harms. Less is known about links to nonoverdose morbidity. We determined the association between prescribed opioid receipt with incident cardiovascular disease (CVD) using data from the Veterans Aging Cohort Study, a national prospective cohort of Veterans with/without Human Immunodeficiency Virus (HIV) receiving Veterans Health Administration care. Selected participants had no/minimal prior exposure to prescription opioids, no opioid use disorder, and no severe illness 1 year after the study start date (baseline period). We ascertained prescription opioid exposure over 3 years after the baseline period using outpatient pharmacy fill/refill data. Incident CVD ascertainment began at the end of the prescribed opioid exposure ascertainment period until the first incident CVD event, death, or September 30, 2015. We used adjusted Cox proportional hazards regression models with matching weights using propensity scores for opioid receipt to estimate CVD risk. Among 49,077 patients, 30% received opioids; the median age was 49 years, 97% were male, 49% were Black, and 47% were currently smoking. Prevalence of hypertension, diabetes, current smoking, alcohol and cocaine use disorder, and depression was higher in patients receiving opioids versus those not but were well-balanced by matching weights. Unadjusted CVD incidence rates per 1,000-person-years were higher among those receiving opioids versus those not: 17.4 (95% confidence interval [CI], 16.5-18.3) versus 14.7 (95% CI, 14.2-15.3). In adjusted analyses, those receiving opioids versus those not had an increased hazard of incident CVD (adjusted hazard ratio 1.16 [95% CI, 1.08-1.24]). Prescribed opioids were associated with increased CVD incidence, making opioids a potential modifiable CVD risk factor. PERSPECTIVE: In a propensity score weighted analysis of Veterans Administration data, prescribed opioids compared to no opioids were associated with an increased hazard of incident CVD. Higher opioid doses compared with lower doses were associated with increased hazard of incident CVD. Opioids are a potentially modifiable CVD risk factor.

10.
Biochemistry ; 62(23): 3347-3359, 2023 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-37967383

RESUMO

Prokaryotes synthesize fatty acids using a type II synthesis pathway (FAS). In this process, the central player, i.e., the acyl carrier protein (ACP), sequesters the growing acyl chain in its internal hydrophobic cavity. As the acyl chain length increases, the cavity expands in size, which is reflected in the NMR chemical shift perturbations and crystal structures of the acyl-ACP intermediates. A few eukaryotic organelles, such as plastids and mitochondria, also harbor type II fatty acid synthesis machinery. Plastid FAS from spinach and Plasmodium falciparum has been characterized at the molecular level, but the mitochondrial pathway remains unexplored. Here, we report NMR studies of the mitochondrial acyl-acyl carrier protein intermediates of Leishmania major (acyl-LmACP). Our studies show that LmACP experiences remarkably small conformational changes upon acylation, with perturbations confined to helices II and III only. CastP determined that the cavity size of apo-LmACP (PDB entry 5ZWT) is less than that of Escherichia coli ACP (PDB 1T8K). Thus, the small chemical shift perturbations observed in the LmACP intermediates, coupled with CastP results, suggest an unusually small cavity when fully expanded. The faster rate of C8-LmACP chain hydrolysis compared to E. coli ACP (EcACP) also supports these convictions. Structure comparison of LmACP with other type II ACP disclosed unique differences in the helix I and loop I conformations, as well as several residues present there. Numerous hydrophobic residues in helix I and loop I (conserved in all mitochondrial ACPs) are substituted with hydrophilic residues in the bacterial/plastid type II ACP. For instance, Phe and leucine at positions 14 and 34 in LmACP are substituted with a hydrophilic residue and Ala in bacterial/plastid type II ACP. Mutation of Leu 34 to Ala (corresponding residue in EcACP) resulted in a complete loss of structure, underscoring its importance in maintaining the ACP fold. Thus, our NMR studies, combined with insights from the crystal structure, highlight several unique features of LmACP, distinct from the prokaryote and plastid type II ACP. Given the high sequence identity, the features might be conserved in all mitochondrial ACPs.


Assuntos
Proteína de Transporte de Acila , Leishmania major , Proteína de Transporte de Acila/metabolismo , Leishmania major/metabolismo , Escherichia coli/metabolismo , Modelos Moleculares , Conformação Molecular
11.
bioRxiv ; 2023 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-37662286

RESUMO

Background: Antibodies to ß2-glycoprotein I (ß2GPI) cause thrombosis in antiphospholipid syndrome, however the role of ß2GPI itself in regulation of coagulation pathways in vivo is not well understood. Methods: We developed ß2GPI-deficient mice (Apoh -/- ) by deleting exon 2 and 3 of Apoh using CRISPR/Cas9 and compared the propensity of wild-type (WT) and Apoh -/- mice to develop thrombosis using rose bengal and FeCl 3 -induced carotid thrombosis, laser-induced cremaster arteriolar injury, and inferior vena cava (IVC) stasis models. We also compared tail bleeding times and assessed platelet activation in WT and Apoh -/- mice in the absence and presence of exogenous ß2GPI. Results: Compared to WT littermates, Apoh -/- mice demonstrated a prolonged time to occlusion of the carotid artery after exposure to rose bengal or FeCl 3 , and reduced platelet and fibrin accumulation in cremasteric arterioles after laser injury. Similarly, significantly smaller thrombi were retrieved from the IVC of Apoh -/- mice 48 hours after IVC occlusion. The activated partial thromboplastin time (aPTT) and prothrombin time, as well as aPTT reagent- and tissue factor-induced thrombin generation times using plasma from Apoh -/- and WT mice revealed no differences. However, we observed significant prolongation of tail bleeding in Apoh -/- mice, and reduced P-selectin expression and binding of fibrinogen to the activated α2bß3 integrin on platelets from these mice after stimulation with low thrombin concentrations; these changes were reversed by exogenous ß2GPI. An antibody to PAR3 blocked thrombin-induced activation of WT, but not Apoh -/- platelets, as well as the ability of ß2GPI to restore the activation response of Apoh -/- platelets to thrombin. ß2GPI deficiency did not affect platelet activation by a PAR4-activator peptide, or ADP. Conclusions: In mice, ß2GPI may mediate procoagulant activity by enhancing the ability of PAR3 to present thrombin to PAR4, promoting platelet activation at low thrombin concentrations. Key Points: ß2GPI deficient mice are protected from experimental arterial, venous, and microvascular thrombosis.ß2GPI deficient mice display prolonged tail bleeding times and reduced PAR3-facilitated platelet activation by low concentrations of thrombin.

13.
Res Sq ; 2023 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-37503102

RESUMO

Lyme disease (LD) is the most prevalent vector borne disease in North America and Europe and its geographic range continues to expand. Strategies for disease control are necessary to effectively reduce incidence of LD including development of safe vaccines for human use. Parainfluenza virus 5 (PIV5) vector has an excellent safety record in animals and PIV5-vectored COVID-19 and RSV vaccines are currently under clinical development. We constructed PIV5-vectored LD vaccine candidates expressing OspA from B. burgdorferi sensu stricto (OspAB31) and a chimeric protein containing sequences from B. burgdorferi and B. afzelii (OspABPBPk). Immunogenicity and vaccine efficacy were analyzed in C3H-HeN mice after prime-boost intranasal (IN) vaccination with PIV5-OspAB31 and PIV5-OspABPBPk, subcutaneous (SC) vaccination with rOspAB31+Alum as well as the respective controls. Mice vaccinated with either PIV5-AB31 or PIV5-ABPBPk intranasally had high endpoint titers of serum antibody against OspA antigen beyond 1 year post vaccination, similar to levels detected in mice vaccinated SC with rOspAB31. Flowcytometric analysis of spleen cells at 9-months post-immunization demonstrated that immunization with the intranasal PIV5 vaccine candidates led to an overall increase in the number of memory B cells, cytotoxic T and cytotoxic effector T cells compared to SC groups. Borreliacidal activity measured by neutralization assay was maintained up to 18 months post-immunization, with the response greater in intranasal PIV5-delivered OspA vaccines, than that induced by SC rOspAB31. Challenge with infected ticks (10-19 strains of B. burgdorferi) performed at 4-, 9- or 15-months post-immunization showed increased breakthrough infections in mice vaccinated with SC rOspAB31 compared to IN PIV5-AB31 or IN PIV5-ABPBPk at 9- and 15-months, as determined by qPCR of B. burgdorferi in tissues, culture of B. burgdorferi from tissues, and antibodies against B. burgdorferi protein VIsE. These data demonstrate that intranasal PIV5-based immunization is superior to parenteral immunization with the same recombinant protein and provides long-lasting protection (> 1 year) against Lyme disease.

14.
Circulation ; 148(2): 135-143, 2023 07 11.
Artigo em Inglês | MEDLINE | ID: mdl-37226738

RESUMO

BACKGROUND: People with HIV (PWH) have an increased risk of cardiovascular disease. Previous cross-sectional data suggest there is a higher prevalence of abdominal aortic aneurysm (AAA) in PWH than in those without HIV. Whether PWH have an increased risk of incident AAA compared with those without HIV is unknown. METHODS: We analyzed data among participants without prevalent AAA from the Veterans Aging Cohort Study, a prospective, observational, longitudinal cohort of veterans with HIV matched 1:2 with veterans without HIV infection. We calculated AAA rates by HIV status and assessed the association between HIV infection and incident AAA using Cox proportional hazards models. We defined AAA using the International Classification of Diseases, 9th or 10th revision, or Current Procedural Terminology codes and adjusted all models for demographic characteristics, cardiovascular disease risk factors, and substance use. Secondary analyses examined the association between time-varying CD4+ T-cell count or HIV viral load and incident AAA. RESULTS: Among 143 001 participants (43 766 with HIV), over a median follow-up of 8.7 years, there were 2431 incident AAA events (26.4% among PWH). Rates of incident AAA per 1000 person-years were similar among PWH (2.0 [95% CI, 1.9-2.2]) and people without HIV (2.2 [95% CI, 2.1-2.3]). There was no evidence that HIV infection increased the risk of incident AAA compared with no HIV infection (adjusted hazard ratio, 1.02 [95% CI, 0.92-1.13]). In adjusted analyses with time-varying CD4+ T-cell counts or HIV viral load, PWH with CD4+ T-cell counts <200 cells/mm3 (adjusted hazard ratio, 1.29 [95% CI, 1.02-1.65]) or HIV viral load ≥500 copies/mL (adjusted hazard ratio, 1.29 [95% CI, 1.09-1.52]) had an increased risk of AAA compared with those without HIV. CONCLUSIONS: HIV infection is associated with an increased risk of AAA among those with low CD4+ T-cell counts or elevated HIV viral load over time.


Assuntos
Aneurisma da Aorta Abdominal , Doenças Cardiovasculares , Infecções por HIV , Veteranos , Humanos , Estudos de Coortes , Fatores de Risco , Doenças Cardiovasculares/epidemiologia , Estudos Prospectivos , Estudos Transversais , Infecções por HIV/diagnóstico , Infecções por HIV/epidemiologia , Aneurisma da Aorta Abdominal/epidemiologia
15.
Nanoscale ; 15(16): 7450-7459, 2023 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-37013963

RESUMO

Mimicking synaptic functions in hardware devices is a crucial step in realizing brain-like computing beyond the von Neumann architecture. 1D nanomaterials with spatial extensions of a few µm, similar to biological neurons, gain significance given the ease of electrical transport as well as directionality. Herein, we report a two-terminal optically active device based on 1D supramolecular nanofibres consisting of CS (coronene tetracarboxylate) and DMV (dimethyl viologen) forming alternating D-A (donor-acceptor) pairs, emulating synaptic functions such as the STP (short-term potentiation), LTP (long-term potentiation), PPF (paired-pulse facilitation), STDP (spike-time dependent plasticity) and learning-relearning behaviors. In addition, an extensive study on the less explored Ebbinghaus forgetting curve has been carried out. The supramolecular nanofibres being light sensitive, the potential of the device as a visual system is demonstrated using a 3 × 3 pixel array.

16.
Int J Biol Macromol ; 240: 124471, 2023 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-37076076

RESUMO

Thermosynechococcus elongatus-BP1 belongs to the class of photoautotrophic cyanobacterial organisms. The presence of chlorophyll a, carotenoids, and phycocyanobilin are the characteristics that categorize T. elongatus as a photosynthetic organism. Here, we report the structural and spectroscopic characteristics of a novel hemoglobin (Hb) Synel Hb from T.elongatus, synonymous with Thermosynechococcus vestitus BP-1. The X-ray crystal structure (2.15 Å) of Synel Hb suggests the presence of a globin domain with a pre-A helix similar to the sensor domain (S) family of Hbs. The rich hydrophobic core accommodates heme in a penta-coordinated state and readily binds an extraneous ligand (imidazole). The absorption and circular dichroic spectral analysis of Synel Hb reiterated that the heme is in FeIII+ state with a predominantly α-helical structure similar to myoglobin. Synel Hb displays higher resistance to structural perturbations induced via external stresses like pH and guanidium hydrochloride, which is comparable to Synechocystis Hb. However, Synel Hb exhibited lower thermal stability compared to mesophilic hemoglobins. Overall, the data is suggestive of the structural sturdiness of Synel Hb, which probably corroborates its origin in extreme thermophilic conditions. The stable globin provides scope for further investigation and may lead to new insights with possibilities for engineering stability in hemoglobin-based oxygen carriers.


Assuntos
Globinas , Synechocystis , Globinas/química , Globinas/metabolismo , Clorofila A , Hemoglobinas/química , Synechocystis/metabolismo , Heme/química , Concentração de Íons de Hidrogênio
17.
ACS Appl Mater Interfaces ; 15(15): 19270-19278, 2023 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-36996388

RESUMO

The detection of ultraviolet (UV) light is vital for various applications, such as chemical-biological analysis, communications, astronomical studies, and also for its adverse effects on human health. Organic UV photodetectors are gaining much attention in this scenario because they possess properties such as high spectral selectivity and mechanical flexibility. However, the achieved performance parameters are much more inferior than the inorganic counterparts because of the lower mobility of charge carriers in organic systems. Here, we report the fabrication of a high-performance visible-blind UV photodetector, using 1D supramolecular nanofibers. The nanofibers are visibly inactive and exhibit highly responsive behavior mainly for UV wavelengths (275-375 nm), the highest response being at ∼275 nm. The fabricated photodetectors demonstrate desired features, such as high responsivity and detectivity, high selectivity, low power consumption, and good mechanical flexibility, because of their unique electro-ionic behavior and 1D structure. The device performance is shown to be improved by several orders through the tweaking of both electronic and ionic conduction pathways while optimizing the electrode material, external humidity, applied voltage bias, and by introducing additional ions. We have achieved optimum responsivity and detectivity values of around 6265 A W-1 and 1.54 × 1014 Jones, respectively, which stand out compared with the previous organic UV photodetector reports. The present nanofiber system has great potential for integration in future generations of electronic gadgets.

19.
ACS Omega ; 8(7): 6632-6637, 2023 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-36844534

RESUMO

Dengue is a common arthropod-borne life-threatening febrile illness. This disease affects liver functions with an imbalance of liver enzymes followed by other clinical manifestations. The dengue serotypes can cause asymptomatic infection to more severe versions of hemorrhagic fever and dengue shock syndrome in West Bengal and around the globe. The main aim of this study is to establish how different liver enzymes act in identifying markers for dengue prognosis for the early detection of severe dengue fever (DF). The diagnosis of dengue patients was confirmed by enzyme-linked immunosorbent assay, and associated clinical parameters [aspartate transaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase, total bilirubin, total albumin, total protein, packed cell volume, and platelet count] were analyzed. Furthermore, the viral load estimation was also carried out by RT PCR analysis. The majority of these patients had elevated AST and ALT levels; ALT levels were higher than AST levels, which were partially observed in all non-structural protein 1 antigen- and dengue immunoglobulin M antibody-reactive patients. Almost 25% of patients had very low platelet count or thrombocytopenia. Furthermore, the viral load shows a significant association with all the clinical parameters with a p-value of <0.0001. All these liver enzymes are significantly correlated with an increased level of T.BIL, ALT, and AST. This study depicts that the intensity of hepatic involvement may play a critical role in the morbidity and mortality of DF patients. As a result, all of these liver parameters can be useful early markers for determining the severity of the disease, allowing for early detection of high-risk cases.

20.
Nat Commun ; 13(1): 6895, 2022 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-36371435

RESUMO

Superconducting qubits seem promising for useful quantum computers, but the currently wide-spread qubit designs and techniques do not yet provide high enough performance. Here, we introduce a superconducting-qubit type, the unimon, which combines the desired properties of increased anharmonicity, full insensitivity to dc charge noise, reduced sensitivity to flux noise, and a simple structure consisting only of a single Josephson junction in a resonator. In agreement with our quantum models, we measure the qubit frequency, ω01/(2π), and increased anharmonicity α/(2π) at the optimal operation point, yielding, for example, 99.9% and 99.8% fidelity for 13 ns single-qubit gates on two qubits with (ω01, α) = (4.49 GHz, 434 MHz) × 2π and (3.55 GHz, 744 MHz) × 2π, respectively. The energy relaxation seems to be dominated by dielectric losses. Thus, improvements of the design, materials, and gate time may promote the unimon to break the 99.99% fidelity target for efficient quantum error correction and possible useful quantum advantage with noisy systems.

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