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1.
Nature ; 610(7931): 283-289, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36224418

RESUMO

The current proliferation of mobile robots spans ecological monitoring, warehouse management and extreme environment exploration, to an individual consumer's home1-4. This expanding frontier of applications requires robots to transit multiple environments, a substantial challenge that traditional robot design strategies have not effectively addressed5,6. For example, biomimetic design-copying an animal's morphology, propulsion mechanism and gait-constitutes one approach, but it loses the benefits of engineered materials and mechanisms that can be exploited to surpass animal performance7,8. Other approaches add a unique propulsive mechanism for each environment to the same robot body, which can result in energy-inefficient designs9-11. Overall, predominant robot design strategies favour immutable structures and behaviours, resulting in systems incapable of specializing across environments12,13. Here, to achieve specialized multi-environment locomotion through terrestrial, aquatic and the in-between transition zones, we implemented 'adaptive morphogenesis', a design strategy in which adaptive robot morphology and behaviours are realized through unified structural and actuation systems. Taking inspiration from terrestrial and aquatic turtles, we built a robot that fuses traditional rigid components and soft materials to radically augment the shape of its limbs and shift its gaits for multi-environment locomotion. The interplay of gait, limb shape and the environmental medium revealed vital parameters that govern the robot's cost of transport. The results attest that adaptive morphogenesis is a powerful method to enhance the efficiency of mobile robots encountering unstructured, changing environments.


Assuntos
Biomimética , Meio Ambiente , Desenho de Equipamento , Robótica , Animais , Biomimética/instrumentação , Biomimética/métodos , Locomoção , Robótica/instrumentação , Robótica/métodos , Tartarugas/fisiologia
2.
Int J Immunogenet ; 51(4): 235-241, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38679820

RESUMO

Vitamin D status has been involved with coronavirus disease 19 (COVID-19) severity. This may be mediated by vitamin D metabolism regulatory genes. Of interest is the vitamin D receptor (VDR) gene, which has been previously associated with other inflammatory and respiratory diseases. In order to investigate the role of VDR gene polymorphisms in COVID-19 severity and outcome, a total of 292 COVID-19 patients were classified according to severity in moderate (n = 56), severe (n = 89) and critical (n = 147) and, according to outcome in survivor (n = 163) and deceased (n = 129), and analysed for FokI and TaqI VDR gene polymorphisms by polymerase chain reaction-based restriction enzyme digestion. The FokI and TaqI single nucleotide polymorphisms (SNPs) were not associated with COVID-19 severity or mortality individually but when analysed by haplotype, TC was associated with an increased risk of presenting critical COVID-19. Additionally, FokI CT genotype was more frequent in COVID-19 patients with hypertension, and T allele carriers presented higher aspartate aminotransferase levels. Our results suggest a relationship between VDR FokI and TaqI SNPs and COVID-19 severity in Mexican population. Although there are some previous reports of VDR polymorphisms in COVID-19, this represents the first report in Latin American population. Further studies on other populations are encouraged.


Assuntos
COVID-19 , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único , Receptores de Calcitriol , SARS-CoV-2 , Índice de Gravidade de Doença , Humanos , Receptores de Calcitriol/genética , COVID-19/genética , Feminino , México , Masculino , Pessoa de Meia-Idade , Idoso , Haplótipos , Adulto , Alelos , Genótipo , Estudos de Coortes , Frequência do Gene
3.
Differentiation ; 132: 41-50, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37202278

RESUMO

The Meibomian gland (MG) is an indispensable adnexal structure of eye that produces meibum, an important defensive component for maintaining ocular homeostasis. Normal development and maintenance of the MGs is required for ocular health since atrophic MGs and disturbances in composition and/or secretion of meibum result in major ocular pathologies, collectively termed as Meibomian gland dysfunction (MGD). Currently available therapies for MGD merely provide symptomatic relief and do not treat the underlying deficiency of the MGs. Hence, a thorough understanding of the timeline of MG development, maturation and aging is required for regenerative purposes along with signaling molecules & pathways controlling proper differentiation of MG lineage in mammalian eye. Understanding the factors that contribute to the development of MGs, developmental abnormalities of MGs, and changes in the quality & quantity of meibum with developing phases of MGs are essential for developing potential treatments for MGD. In this review, we compiled a timeline of events and the factors involved in the structural and functional development of MGs and the associated developmental defects of MGs during development, maturation and aging.


Assuntos
Doenças Palpebrais , Glândulas Tarsais , Animais , Glândulas Tarsais/metabolismo , Doenças Palpebrais/metabolismo , Lágrimas/química , Lágrimas/metabolismo , Mamíferos
4.
Sensors (Basel) ; 24(9)2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38732813

RESUMO

This article presents a technique for reducing the stabilization length of steady-state modes in step-index plastic optical fibers (POFs), which is significant for sensor networks, Internet of Things, signal processing, and data fusion in sensor systems. The results obtained with the com- putational tool developed suggest that the D-shape created in the POF effectively reduces the stabi- lization length of the modes and, by extension, minimizes the dispersion effects of the modes by filtering out high-order modes. Applying the analysis to commercial POFs, the authors experimen- tally verified a reduction in the stabilization length of modes from 27 to 10 m and from 20 m to 5 m. Reducing the mode stabilization length minimizes the bit error rate (BER) in short-length SI-POF- based optical links operating at 250 Mbp/s. A reduction from 7.6 × 10-7 to 3.7 × 10-10 was achieved.

5.
Curr Issues Mol Biol ; 45(8): 6842-6850, 2023 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-37623251

RESUMO

HLA-G is a physiology and pathologic immunomodulator detrimentally related to cancer. Its gene is heavily transcriptionally and post-transcriptionally regulated by variants located in regulator regions like 3'UTR, being the most studied Ins/Del of 14-bp (rs66554220), which is known to influence the effects of endogen cell factors; nevertheless, the reports are discrepant and controversial. Herein, the relationship of the 14-bp Ins/Del variant (rs66554220) with breast cancer (BC) and its clinical characteristics were analyzed in 182 women with non-familial BC and 221 disease-free women as a reference group. Both groups from western Mexico and sex-age-matched (sm-RG). The rs66554220 variant was amplified by SSP-PCR and the fragments were visualized in polyacrylamide gel electrophoresis. The variant rs66554220 was not associated with BC in our population. However, we suggest the Ins allele as a possible risk factor for developing BC at clinical stage IV (OR = 3.05, 95% CI = 1.16-7.96, p = 0.01); nevertheless, given the small stratified sample size (n = 11, statistical power = 41%), this is inconclusive. In conclusion, the 14-bp Ins/Del (rs66554220) variant of HLA-G is not associated with BC in the Mexican population, but might be related to advanced breast tumors. Further studies are required.

6.
Artigo em Inglês | MEDLINE | ID: mdl-37574653

RESUMO

ABSTRACT: Appendiceal neuroendocrine neoplasm (NEN) is the most common adult appendiceal malignant tumor, constituting 16% of gastrointestinal NENs. They are versatile tumors with varying morphology, immunohistochemistry, secretory properties, and cancer genomics. They are slow growing and clinically silent, to begin with, or present with features of nonspecific vague abdominal pain. Most acute presentations are attributed clinically to appendicitis, with most cases detected incidentally on pathology after an appendectomy. Approximately 40% of them present clinically with features of hormonal excess, which is likened to the functional secretory nature of their parent cell of origin. The symptoms of carcinoid syndrome render their presence clinically evident. However, slow growing and symptomatically silent in its initial stages, high-grade neuroendocrine tumors and neuroendocrine carcinomas of the appendix are aggressive and usually have hepatic and lymph node metastasis at presentation. This review article focuses on imaging characteristics, World Health Organization histopathological classification and grading, American Joint Committee on Cancer/Union or International Cancer Control, European Neuroendocrine Tumor Society staging, European Neuroendocrine Tumor Society standardized guidelines for reporting, data interpretation, early-stage management protocols, and advanced-stage appendiceal NENs. Guidelines are also set for the follow-up and reassessment. The role of targeted radiotherapy, chemotherapy, and high-dose somatostatin analogs in treating advanced disease are discussed, along with types of ablative therapies and liver transplantation for tumor recurrence. The search for newer location-specific biomarkers in NEN is also summarized. Regarding the varying aggressiveness of the tumor, there is a scope for research in the field, with plenty of data yet to be discovered.

7.
Int J Mol Sci ; 25(1)2023 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-38203252

RESUMO

The emergence of bacterial strains displaying resistance to the currently available antibiotics is a critical global concern. These resilient bacteria can form biofilms that play a pivotal role in the failure of bacterial infection treatments as antibiotics struggle to penetrate all biofilm regions. Consequently, eradicating bacteria residing within biofilms becomes considerably more challenging than their planktonic counterparts, leading to persistent and chronic infections. Among various approaches explored, essential oils loaded in nanoparticles based on biopolymers have emerged, promising strategies that enhance bioavailability and biological activities, minimize side effects, and control release through regulated pharmacokinetics. Different available reviews analyze nanosystems and essential oils; however, usually, their main goal is the analysis of their antimicrobial properties, and progress in biofilm combat is rarely discussed, or it is not the primary objective. This review aims to provide a global vision of biofilm conformation and describes mechanisms of action attributed to each EO. Furthermore, we present a comprehensive overview of the latest developments in biopolymeric nanoparticles research, especially in chitosan- and zein-based nanosystems, targeting multidrug-resistant bacteria in both their sessile and biofilm forms, which will help to design precise strategies for combating biofilms.


Assuntos
Nanopartículas , Óleos Voláteis , Antibacterianos/farmacologia , Biofilmes , Disponibilidade Biológica
8.
Postepy Dermatol Alergol ; 40(2): 246-252, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37312918

RESUMO

Introduction: The HLA-G molecule functions as a critical immunomodulatory checkpoint, its expression is significantly associated with pathological processes that may be responsible in part for autoimmune conditions such as non-segmental vitiligo (NS-V), characterized by chronic skin depigmentation. In this sense, the rs66554220 (14 bp ID) variant located in the 3'UTR, implicated in the regulation of HLA-G production, is associated with autoimmune diseases. Aim: To evaluate the role of the HLA-G rs66554220 variant in NS-V and its clinical features in Northwestern Mexicans. Material and methods: We genotyped the rs66554220 variant by SSP-PCR in 197 NS-V patients and 198 age-sex matched non-related healthy individuals (HI). Results: Del allele and genotype Del/Ins were the most prevalent in both study groups (NS-V/HI = 56%/55% and 46.70%/46.46%, respectively). Despite lacking association between the variant and NS-V, we found an association of the Ins allele in different inheritance models with familial clustering, onset of the illness, universal clinical subtype and Koebner's phenomenon. Conclusions: The rs66554220 (14 bp ID) variant is not a risk factor for NS-V in the Mexican population studied. To our knowledge, this is the first report about the topic in the Mexican population and worldwide that includes clinical features related with this HLA-G genetic variant.

9.
Sex Transm Dis ; 49(8): e90-e94, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35001015

RESUMO

ABSTRACT: The recent detection of hepatitis C virus genotype 4 infection in human immunodeficiency virus-infected patients prompted performing molecular characterization of these isolates. All the Mexican isolates belonged to a subcluster within the 4d group and shared a common ancestor with a French isolate. The estimated timing of introduction in Mexico City was as recent as December 2015.


Assuntos
Infecções por HIV , Hepatite C , Genótipo , HIV , Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Hepacivirus/genética , Hepatite C/epidemiologia , Humanos , México/epidemiologia
10.
Immunol Invest ; 51(5): 1398-1406, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34251960

RESUMO

Diabetic kidney disease (DKD) is one of the more limiting complications to the quality of life of diabetes mellitus patients. Studies including cultured cells, animal models, and case-control studies highlight the role of human ß-defensin-1 (hBD-1) in diabetes.This study assessed the association of hBD-1 gene (DEFB1) functional variations -52 G/A (rs1799946), -44 C/G (rs1800972) and -20 G/A (rs11362) with type 2 diabetes mellitus (T2DM) in order to investigate its effects on genetic susceptibility and progression to DKD in a Mexican population. A total of 214 T2DM patients with and without DKD (n = 102 and n = 112, respectively) and 117 healthy subjects participated in this case-control study. Genotyping was made by PCR-RFLPs. Clinical and biochemical parameters of all patients were measured. There was no statistically significant difference in genotype or allele frequencies between patients and healthy individuals. Nevertheless, compared with patients without DKD, DKD patients have a reduced prevalence of AA genotype of -52 G/A (OR = 0.307, 95% CI = 0.104-0.905, p =.026), as well as a higher frequency of GA genotype of -20 G/A variant (OR = 1.875, 95%CI = 1.031-3.409, p = .038). Our results suggest that rs1799946 and rs11362 could be useful variants to stratify T2DM Mexican patients in order to prescribe closer follow-up to prevent or retard DKD. Further tests in different ethnic groups are encouraged.


Assuntos
Diabetes Mellitus Tipo 2 , Nefropatias Diabéticas , beta-Defensinas , Estudos de Casos e Controles , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/genética , Nefropatias Diabéticas/genética , Predisposição Genética para Doença , Humanos , México , Polimorfismo de Nucleotídeo Único , Qualidade de Vida , beta-Defensinas/genética
11.
Parasitology ; 149(3): 418-426, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34814960

RESUMO

Congenital transmission of Chagas disease plays an important role in endemic countries because it is not a diagnosis that is encountered frequently in prenatal care. Due to limited information regarding congenital transmission of Trypanosoma cruzi in Mexico, the present study aimed to investigate protozoan infectivity and modulation of immune responses in human placental explants infected with T. cruzi Ia Mexican strains. The Inc-5 strain showed increased infectivity and modulated IL-1ß, IL-10 and TLR-4, decreasing their expression after 24 h of infection. Both strains (Inc-5 and Ninoa) stimulated the production of TNF-α and decreased IL-6 levels 96 h after infection. An important detachment of the syncytiotrophoblast caused by infection with T. cruzi was observed after 24 h of infection. In this study, ex vivo infection of human placental villi was performed to better understand interactions involving parasitic T. cruzi and human placental tissue. It was concluded that the strains of TcIa present parasitism in placental tissue, modulation of the innate immune system of the placenta, and cause intense detachment of the syncytiotrophoblast, a fact that may be more associated with abortion and premature birth events than the congenital transmission itself, justifying the low rate of this transmission mechanism by this genotype.


Assuntos
Doença de Chagas , Parasitos , Trypanosoma cruzi , Animais , Doença de Chagas/parasitologia , Feminino , Humanos , México , Placenta/parasitologia , Gravidez , Trypanosoma cruzi/fisiologia
12.
Phys Chem Chem Phys ; 24(48): 29999-30009, 2022 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-36472147

RESUMO

Join counting, a standard technique in spatial autocorrelation analysis, has been used to quantify the clustering of carbon, fluorine and sodium in cross-sectioned anode and cathode samples. The sample preparation and EDS mapping steps are sufficiently fast for every coating from two Design of Experiment (DoE) test matrices to be characterised. The results show two types of heterogeneity in material distribution; gradients across the coating from the current collector to the surface, and clustering. In the cathode samples, the carbon is more clustered than the fluorine, implying that the conductive carbon component is less well distributed than the binder. The results are correlated with input parameters systematically varied in the DoE e.g. coating blade gap, coating speed, and other output parameters e.g. coat weight, and electrochemical resistance.

13.
Sensors (Basel) ; 22(2)2022 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-35062417

RESUMO

Analyzing data related to the conditions of city streets and avenues could help to make better decisions about public spending on mobility. Generally, streets and avenues are fixed as soon as they have a citizen report or when a major incident occurs. However, it is uncommon for cities to have real-time reactive systems that detect the different problems they have to fix on the pavement. This work proposes a solution to detect anomalies in streets through state analysis using sensors within the vehicles that travel daily and connecting them to a fog-computing architecture on a V2I network. The system detects and classifies the main road problems or abnormal conditions in streets and avenues using Machine Learning Algorithms (MLA), comparing roughness against a flat reference. An instrumented vehicle obtained the reference through accelerometry sensors and then sent the data through a mid-range communication system. With these data, the system compared an Artificial Neural Network (supervised MLA) and a K-Nearest Neighbor (Supervised MLA) to select the best option to handle the acquired data. This system makes it desirable to visualize the streets' quality and map the areas with the most significant anomalies.


Assuntos
Algoritmos , Aprendizado de Máquina , Análise por Conglomerados , Sistemas Computacionais , Redes Neurais de Computação
14.
Molecules ; 27(13)2022 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-35807351

RESUMO

ß-Glucosidase is part of the cellulases and is responsible for degrading cellobiose into glucose, a compound that can be used to produce biofuels. However, the use of the free enzyme makes the process more expensive. Enzyme immobilization improves catalytic characteristics and supports, such as zeolites, which have physical-chemical characteristics and ion exchange capacity that have a promising application in the biotechnological industry. This research aimed to immobilize by adsorption a recombinant ß-glucosidase from Trichoderma reesei, obtained in Escherichia coli BL21 (DE3), in a commercial zeolite. A Box Behnken statistical design was applied to find the optimal immobilization parameters, the stability against pH and temperature was determined, and the immobilized enzyme was characterized by SEM. The highest enzymatic activity was determined with 100 mg of zeolite at 35 °C and 175 min. Compared to the free enzyme, the immobilized recombinant ß-glucosidase presented greater activity from pH 2 to 4 and greater thermostability. The kinetic parameters were calculated, and a lower KM value was obtained for the immobilized enzyme compared to the free enzyme. The obtained immobilization parameters by a simple adsorption method and the significant operational stability indicate promising applications in different fields.


Assuntos
Zeolitas , beta-Glucosidase , Estabilidade Enzimática , Enzimas Imobilizadas/química , Concentração de Íons de Hidrogênio , Hidrólise , Temperatura , beta-Glucosidase/metabolismo
15.
Int Arch Allergy Immunol ; 182(2): 131-138, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32957109

RESUMO

INTRODUCTION: The European Network of Drug Allergy and the European Academy of Allergy and Clinical Immunology have classified hypersensitivity reactions induced by nonsteroidal anti-inflammatory drugs (NSAIDs) into 5 phenotypes according to the pathophysiology, clinical manifestations, number of drugs involved, and the presence of underlying diseases. This classification does not include anaphylaxis as part of NSAID cross-reactivity. The objective of this study was to characterize a group of patients with anaphylactic NSAID cross-reactivity. METHOD: This was a retrospective, descriptive, observational study. Patients who developed anaphylaxis to one NSAID plus another acute reaction (anaphylactic or not) to at least one other NSAID of a different chemical group were included. Demographic and clinical characteristics and the diagnostic approach were studied. RESULTS: A total of 38 patients were included, 28 (73.7%) of whom were women. The mean age was 40 ± 17.7 years. The main organs affected in the anaphylactic reaction were the skin and the respiratory system, occurring in 35 (92.1%) and 33 (86.8%) patients, respectively. Thirty-two (84.3%) patients presented with cutaneous and respiratory involvement simultaneously. The main anti-inflammatory agent involved in anaphylactic reactions was acetylsalicylic acid in 9 (23.7%) patients, followed by dipyrone in 8 (21.1%). The most frequent allergic comorbidity was rhinitis in 20 (52%) patients. Skin tests were performed in 15 (39.5%) patients, showing positivity in 12 (80%), mainly to mites. A total of 36 of 38 patients were challenged with alternative drugs, and 35 (97.2%) tolerated meloxicam and/or etoricoxib. CONCLUSION: In the present study, NSAID cross-anaphylaxis was more frequent in women, and acetylsalicylic acid and dipyrone were the main triggers. Rhinitis was the main allergic comorbidity, and there was a high incidence of atopy. The majority tolerated selective COX-2 NSAIDs.


Assuntos
Anafilaxia/diagnóstico , Anafilaxia/etiologia , Anti-Inflamatórios não Esteroides/efeitos adversos , Reações Cruzadas/imunologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fenótipo , Estudos Retrospectivos , Índice de Gravidade de Doença , Testes Cutâneos , Avaliação de Sintomas , Adulto Jovem
16.
Nanotechnology ; 32(15): 155605, 2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33321480

RESUMO

Single and few-layered MoS2 materials have attracted attention due to their outstanding physicochemical properties with potential applications in optoelectronics, catalysis, and energy storage. In the past, these materials have been produced using the chemical vapor deposition (CVD) method using MoO3 films and powders as Mo precursors. In this work, we demonstrate that the size and morphology of few-layered MoS2 nanostructures can be controlled, modifying the Mo precursor mechanically. We synthesized few-layered MoS2 materials using MoO3 powders previously exposed to a high-energy ball milling treatment by the salt-assisted CVD method. The MoO3 powders milled for 30, 120, and 300 min were used to synthesize sample MoS2-30, MoS2-120, and MoS2-300, respectively. We found morphologies mainly of hexagons (MoS2-30), triangles (MoS2-120), and fullerenes (MoS2-300). The MoS2 nanostructures and MoO3 powders were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, x-ray diffraction, and thermogravimetric analysis. It was found that MoO3 milled powders exhibit oxygen loss and decrease in crystallite size as milling time increases. Oxygen deficiency in the Mo precursor prevents the growth of large MoS2 crystals and a large number of milled MoO3-x  + NaCl promote greater nucleation sites for the formation of MoS2, achieving a high density of nanoflakes in the 2H and 3R phases, with diameter sizes in the range of ∼30-600 nm with 1-12 layers. Photoluminescence characterization at room temperature revealed a direct bandgap and exciting trends for the different MoS2 samples. We envisage that our work provides a route for modifying the structure and optical properties for future device design via precursor engineering.

17.
Phys Chem Chem Phys ; 23(4): 2953-2963, 2021 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-33480904

RESUMO

Spectroscopic properties such as equilibrium distances, vibrational constants, rotational constants, dissociation energies, and excitation energies are calculated for nine heteronuclear diatomic molecules (PH, NF, NH, NO, CS, AlF, ClF, BeO and CF) using an interactive pair model (PNOF7s), that has been generalized for spin multiplet states, and its second order perturbation variant, NOF-MP2, which was also generalized for multiplets. The results obtained are compared with Complete Active Space (CASSCF) and Complete Active Space Perturbation Theory (CASPT2). It is shown that the potential energy curves provided by the PNOF functional for open shell diatomic molecules are in acceptable agreement with those from CASSCF and CASPT2. The spectroscopic constants depending at most on the second derivative of the potential energy are in good agreement with experiment, while those requiring the evaluation of the third and fourth derivatives show larger deviations from experiment and from those predicted by CASPT2. Thus, it is shown that the PNOF functional extension to multiplets is an alternative approach in predicting spectroscopic constants of molecules where static correlation plays an important role, like the open shell heteronuclear diatomic molecules studied in this work.

18.
Curr Microbiol ; 78(3): 932-943, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33580332

RESUMO

Rice (Oryza sativa L.) is a staple food for more than two billion people worldwide. Its cultivation demands large amounts of nutrients, particularly nitrogen and phosphorus (P). Consequently, low availability of these nutrients in the soil has led to the use of chemical fertilizers, generating increases in production costs and environmental damage. Soil host microorganisms known as plant growth-promoting rhizobacteria (PGPR) colonize the rhizosphere and facilitate the uptake of nutrients by the plants. In this study, rice seeds inoculated with PGPR were grown for 30 days in an inert substrate and fertilized with modified Hoagland nutrient solution with phosphate rock as a source of P. Treatments were repeated over time, obtaining five isolates which significantly increased plant length by up to 56% and dry weight of stems and roots up to 45% and 169% respectively relative to an uninoculated control. Selected strains showed in vitro tri-calcium phosphate solubilizing activity, mineralizing phytate activity, and phosphate release from rice straw (RS). Based on the above criteria, three isolates (IBUN-02755, -02,704 and -02,724) that contained ß propeller phytase (BPP) genes, were selected to evaluate their effect as PGPR in rice seedlings. These were planted in a soil amended with RS under greenhouse conditions. The results showed that selected Bacillus spp. strains significantly increased plant length and dry weight or increased plant phosphate uptake up to two times compared to an un-inoculated control. This suggests that selected strains may have a capacity as PGPR using RS as carbon and a P amendment.


Assuntos
Bacillus , Oryza , Bacillus/genética , Humanos , Fósforo , Raízes de Plantas , Rizosfera , Solo , Microbiologia do Solo
19.
J Vis ; 21(6): 6, 2021 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-34115108

RESUMO

Temporal attention, the allocation of attention to a moment in time, improves perception. Here, we examined the computational mechanism by which temporal attention improves perception, under a divisive normalization framework. Under this framework, attention can improve perception of a target signal in three ways: stimulus enhancement (increasing gain across all sensory channels), signal enhancement (selectively increasing gain in channels that encode the target stimulus), or external noise exclusion (reducing the gain in channels that encode irrelevant features). These mechanisms make diverging predictions when a target is embedded in varying levels of noise: stimulus enhancement improves performance only when noise is low, signal enhancement improves performance at all noise intensities, and external noise exclusion improves performance only when noise is high. To date, temporal attention studies have used noise-free displays. Therefore, it is unclear whether temporal attention acts via stimulus enhancement (amplifying both target features and noise) or signal enhancement (selectively amplifying target features) because both mechanisms predict improved performance in the absence of noise. To tease these mechanisms apart, we manipulated temporal attention using an auditory cue while parametrically varying external noise in a fine-orientation discrimination task. Temporal attention improved perceptual thresholds across all noise levels. Formal model comparisons revealed that this cuing effect was best accounted for by a combination of signal enhancement and stimulus enhancement, suggesting that temporal attention improves perceptual performance, in part, by selectively increasing gain for target features.


Assuntos
Sinais (Psicologia) , Ruído , Humanos
20.
Int J Mol Sci ; 22(24)2021 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-34948188

RESUMO

Human serum transferrin (Tf) is a bilobed glycoprotein whose function is to transport iron through receptor-mediated endocytosis. The mechanism for iron release is pH-dependent and involves conformational changes in the protein, thus making it an attractive system for possible biomedical applications. In this contribution, two powerful X-ray techniques, namely Macromolecular X-ray Crystallography (MX) and Small Angle X-ray Scattering (SAXS), were used to study the conformational changes of iron-free (apo) and iron-loaded (holo) transferrin in crystal and solution states, respectively, at three different pH values of physiological relevance. A crystallographic model of glycosylated apo-Tf was obtained at 3.0 Å resolution, which did not resolve further despite many efforts to improve crystal quality. In the solution, apo-Tf remained mostly globular in all the pH conditions tested; however, the co-existence of closed, partially open, and open conformations was observed for holo-Tf, which showed a more elongated and flexible shape overall.


Assuntos
Transferrina/ultraestrutura , Sítios de Ligação/fisiologia , Cristalografia por Raios X/métodos , Glicosilação , Humanos , Concentração de Íons de Hidrogênio , Ferro/metabolismo , Modelos Moleculares , Ligação Proteica/fisiologia , Conformação Proteica , Espalhamento a Baixo Ângulo , Soro/química , Soro/metabolismo , Transferrina/metabolismo , Difração de Raios X
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