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1.
J Biomed Inform ; 139: 104300, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36736446

RESUMO

Diabetes Mellitus (DM) is a group of metabolic disorders characterized by hyperglycaemia in the absence of treatment. Classification of DM is essential as it corresponds to the respective diagnosis and treatment. In this paper, we propose a new coupling network with hierarchical dual-attention that utilizes heterogeneous data, including Flash Glucose Monitoring (FGM) data and biomarkers in electronic medical records. The long short-term memory-based FGM sub-network extracts the time-dependent features of dynamic FGM sequences, while the biomarkers sub-network learns the features of static biomarkers. The convolutional block attention module (CBAM) for dispersing the feature weights of the spatial and channel dimensions is implemented into the FGM sub-network to endure the variability of FGM and allows us to extract high-level discriminative features more accurately. To better adjust the importance weights of the characteristics of the two sub-networks, self-attention is introduced to integrate the characteristics of heterogeneous data. Based on the dataset provided by Peking University People's Hospital, the proposed method is evaluated through factorial experiments of multi-source heterogeneous data, ablation studies of various attention strategies, time consumption evaluation and quantitative evaluation. The benchmark tests reveal the proposed network achieves a type 1 and 2 diabetes classification accuracy of 95.835% and the comprehensive performance metrics, including Matthews correlation coefficient, F1-score and G-mean, are 91.333%, 94.939% and 94.937% respectively. In the factorial experiments, the proposed method reaches the maximum area under the receiver operating characteristic curve of 0.9428, which indicates the effectiveness of the coupling between the nominated sub-networks. The coupling network with a dual-attention strategy performs better than the one without or only with a single-attention strategy in the ablation study as well. In addition, the model is also tested on another data set, and the accuracy of the test reaches 94.286%, reflecting that the model is robust when it is transferred to untrained diabetes data. The experimental results show that the proposed method is feasible in the classification of diabetes types. The code is available at https://github.com/bitDalei/Diabetes-Classification-with-Heterogeneous-Data.


Assuntos
Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Humanos , Automonitorização da Glicemia , Glicemia , Benchmarking
2.
Eur J Nucl Med Mol Imaging ; 48(11): 3493-3501, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33829416

RESUMO

PURPOSE: Renal fibrosis is a pathological state in the progression of chronic kidney disease. Early detection and treatment are vital to prolonging patient survival. Renal puncture examination is the gold standard for renal fibrosis, but it has several limitations. This study aims to evaluate the diagnostic performance of a novel PET radiotracer, [68Ga]Ga-fibroblast activation protein inhibitor (FAPI)-04, which specifically images fibroblast activation protein (FAP) expression for renal fibrosis. METHODS: All patients underwent renal puncture before receiving [68Ga]Ga-FAPI-04 PET/CT imaging. They then underwent [68Ga]Ga-FAPI-04 PET/CT and immunochemistry examinations. The data obtained were analyzed. RESULTS: The [68Ga]Ga-FAPI-04 PET/CT examination results demonstrated that almost all patients (12/13) exhibited increased radiotracer uptake. The maximum standardized uptake value (SUVmax) in patients with mild, moderate, and severe fibrosis was 3.92 ± 1.50, 5.98 ± 1.6, and 7.67 ± 2.23, respectively. CONCLUSION: Compared with renal puncture examination, non-invasive imaging of FAP expression through [68Ga]Ga-FAPI-04 PET/CT quickly demonstrates bilateral kidney conditions with high sensitivity. [68Ga]Ga-FAPI-04 PET/CT can facilitate the evaluation of disease progression, diagnosis, and the development of a treatment plan.


Assuntos
Radioisótopos de Gálio , Quinolinas , Fibrose , Humanos , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada
3.
Diabetes Obes Metab ; 23(3): 774-781, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33269509

RESUMO

AIM: We aimed to use data-driven glucose pattern analysis to unveil the correlation between the metrics reflecting glucose fluctuation and beta-cell function, and to identify the possible role of this metric in diabetes classification. MATERIALS AND METHODS: In total, 78 participants with type 1 diabetes and 59 with type 2 diabetes were enrolled in this study. All participants wore a flash glucose monitoring system, and glucose data were collected. A detrended fluctuation function (DFF) was utilized to extract glucose fluctuation information from flash glucose monitoring data and a DFF-based glucose fluctuation metric was proposed. RESULTS: For the entire study population, a significant negative correlation between the DFF-based glucose fluctuation metric and fasting C-peptide was observed (r = -0.667; P <.001), which was larger than the correlation coefficient between the fasting C-peptide and mean amplitude of plasma glucose excursions (r = -0.639; P < .001), standard deviation (r = -0.649; P <.001), mean blood glucose (r = -0.519; P < .001) and time in range (r = 0.593; P < .001). As glucose data analysed by DFF revealed a clear bimodal distribution among the total participants, we randomly assigned the 137 participants into discovery cohorts (n = 100) and validation cohorts (n = 37) for 10 times to evaluate the consistency and effectiveness of the proposed metric for diabetes classification. The confidence interval for area under the curve according to the receiver operating characteristic analysis in the 10 discovery cohorts achieved (0.846, 0.868) and that for the 10 validation cohorts was (0.799, 0.862). In addition, the confidence intervals for sensitivity and specificity in the discovery cohorts were (75.5%, 83.0%), (81.3%, 88.5%) and (71.8%, 88.3%), (76.5%, 90.3%) in the validation cohorts, indicating the potential capacity of DFF in distinguishing type 1 and type 2 diabetes. CONCLUSIONS: Our study first proposed the possible role of data-driven analysis acquired glucose metric in predicting beta-cell function and diabetes classification, and a large-scale, multicentre study will be needed in the future.


Assuntos
Diabetes Mellitus Tipo 1 , Diabetes Mellitus Tipo 2 , Glicemia , Automonitorização da Glicemia , Peptídeo C , Humanos
4.
Arch Virol ; 166(9): 2443-2450, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34173062

RESUMO

Cats infected with feline calicivirus (FCV) often display oral ulcers and inflammation of the upper respiratory tract, which can lead to death in severe cases. Antiviral therapy is one of the most effective ways to control FCV infection. Natural compounds in Chinese herbal medicines and medicinal plants provide abundant resources for research on antiviral drugs. In this study, we found that icariin (ICA), formononetin (FMN) and caffeic acid phenethyl ester (CPAE) show low cytotoxicity towards F81 cells, that the three natural compounds have apparent antiviral effects on FCV in vitro, and that they can inhibit different FCV strains. Then, we found that ICA and FMN mainly function in the early stage of FCV infection, while CAPE can function in both the early and late stages of FCV infection. Finally, we found that ICA has an antagonistic effect on FMN and CAPE in FCV infection, and FMN has a synergistic effect with CAPE against FCV infection. Our results showed that ICA, FMN and CAPE may be potential drug candidates for FCV-induced diseases.


Assuntos
Antivirais/farmacologia , Ácidos Cafeicos/farmacologia , Calicivirus Felino/efeitos dos fármacos , Flavonoides/farmacologia , Isoflavonas/farmacologia , Álcool Feniletílico/análogos & derivados , Álcool Feniletílico/farmacologia , Replicação Viral/efeitos dos fármacos , Animais , Infecções por Caliciviridae/tratamento farmacológico , Doenças do Gato/tratamento farmacológico , Gatos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Interações Medicamentosas
5.
FASEB J ; 33(8): 9350-9361, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31125263

RESUMO

The establishment of ungulate embryonic stem cells (ESCs) has been notoriously difficult via a conventional approach. We combined a traditional ESC culture method with reprogramming factors to assist the establishment of porcine naive-like ESCs (nESCs). Pig embryonic fibroblasts were transfected with a tetracycline-inducible vector carrying 4 classic mouse reprogramming factors, followed by somatic cell nuclear transfer and culturing to the blastocyst stage. Then, the inner cell mass was isolated and seeded in culture medium. The naive-like ESCs had characteristic verys similar to those of mouse ESCs and showed no signs of altered morphology or differentiation, even after 130 passages. They depended on leukemia inhibitory factor signals for maintenance of pluripotency, and the female cell lines had low expression of the X-inactive specific transcript gene and no histone H3 lysine 27 trimethylation spot. Notably, the ESCs differentiated into 3 germ layers in vitro and could be induced to undergo directional neural and kidney precursor differentiation under defined conditions, and the ESCs could keep proliferating after doxycycline was removed. nESCs can be established, and the well-characterized ESC lines will be useful for the research of transgenic pig models for human disease.-Zhang, M., Wang, C., Jiang, H., Liu, M., Yang, N., Zhao, L., Hou, D., Jin, Y., Chen, Q., Chen, Y., Wang, J., Dai, Y., Li, R. Derivation of novel naive-like porcine embryonic stem cells by a reprogramming factor-assisted strategy.


Assuntos
Reprogramação Celular/fisiologia , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Animais , Células Cultivadas , Reprogramação Celular/efeitos dos fármacos , Reprogramação Celular/genética , Células-Tronco Embrionárias/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Camadas Germinativas/citologia , Camadas Germinativas/efeitos dos fármacos , Camadas Germinativas/metabolismo , Imuno-Histoquímica , Fator Inibidor de Leucemia/farmacologia , Camundongos , MicroRNAs/metabolismo , Células-Tronco Pluripotentes/citologia , Células-Tronco Pluripotentes/efeitos dos fármacos , Células-Tronco Pluripotentes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de RNA , Suínos
6.
Sensors (Basel) ; 20(17)2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32878028

RESUMO

Stability is a prerequisite for legged robots to execute tasks and traverse rough terrains. To guarantee the stability of quadruped locomotion and improve the terrain adaptability of quadruped robots, a stability-guaranteed and high terrain adaptability static gait for quadruped robots is addressed. Firstly, three chosen stability-guaranteed static gaits: intermittent gait 1&2 and coordinated gait are investigated. In addition, then the static gait: intermittent gait 1, which is with the biggest stability margin, is chosen to do a further research about quadruped robots walking on rough terrains. Secondly, a position/force based impedance control is employed to achieve a compliant behavior of quadruped robots on rough terrains. Thirdly, an exploratory gait planning method on uneven terrains with touch sensing and an attitude-position adjustment strategy with terrain estimation are proposed to improve the terrain adaptability of quadruped robots. Finally, the proposed methods are validated by simulations.

7.
Sensors (Basel) ; 20(19)2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33019529

RESUMO

The wheel-legged hybrid robot (WLHR) is capable of adapting height and wheelbase configuration to traverse obstacles or rolling in confined space. Compared with legged and wheeled machines, it can be applied for more challenging mobile robotic exercises using the enhanced environment adapting performance. To make full use of the deformability and traversability of WHLR with parallel Stewart mechanism, this paper presents an optimization-driven planning framework for WHLR with parallel Stewart mechanism by abstracting the robot as a deformable bounding box. It will improve the obstacle negotiation ability of the high degree-of-freedoms robot, resulting in a shorter path through adjusting wheelbase of support polygon or trunk height instead of using a fixed configuration for wheeled robots. In the planning framework, we firstly proposed a pre-calculated signed distance field (SDF) mapping method based on point cloud data collected from a lidar sensor and a KD -tree-based point cloud fusion approach. Then, a covariant gradient optimization method is presented, which generates smooth, deformable-configuration, as well as collision-free trajectories in confined narrow spaces. Finally, with the user-defined driving velocity and position as motion inputs, obstacle-avoidancing actions including expanding or shrinking foothold polygon and lifting trunk were effectively testified in realistic conditions, demonstrating the practicability of our methodology. We analyzed the success rate of proposed framework in four different terrain scenarios through deforming configuration rather than bypassing obstacles.

8.
Xenotransplantation ; 26(3): e12484, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30623494

RESUMO

SIX1 and SIX4 genes play critical roles in kidney development. We evaluated the effect of these genes on pig kidney development by generating SIX1-/- and SIX1-/- /SIX4-/- pig foetuses using CRISPR/Cas9 and somatic cell nuclear transfer. We obtained 3 SIX1-/- foetuses and 16 SIX1-/- /SIX4-/- foetuses at different developmental stages. The SIX1-/- foetuses showed a migration block of the left kidney and a smaller size for both kidneys. The ureteric bud failed to form the normal branching and collecting system. Abnormal expressions of kidney development-related genes (downregulation of PAX2, PAX8, and BMP4 and upregulation of EYA1 and SALL1) were also observed in SIX1-/- foetal kidneys and confirmed in vitro in porcine kidney epithelial cells (PK15) following SIX1 gene deletion. The SIX1-/- /SIX4-/- foetuses exhibited more severe phenotypes, with most foetuses showing retarded development at early stages of gestation. The kidney developed only to the initial stage of metanephros formation. These results demonstrated that SIX1 and SIX4 are key genes for porcine metanephros development. The creation of kidney-deficient porcine foetuses provides a platform for generating human kidneys inside pigs using blastocyst complementation.


Assuntos
Sistemas CRISPR-Cas/genética , Marcação de Genes , Genes Homeobox/genética , Proteínas Nucleares/metabolismo , Animais , Blastocisto/metabolismo , Proteínas de Homeodomínio/genética , Técnicas de Transferência Nuclear , Suínos , Transativadores/genética , Transplante Heterólogo/métodos
9.
Langmuir ; 34(26): 7738-7743, 2018 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-29806943

RESUMO

Monodisperse patchy silica nanoparticles (PSNPs) less than 100 nm are prepared based on the seed-regrowth method using a poly(ethylene oxide) (PEO)-poly(propylene oxide) (PPO)-PEO-type block copolymer as a surface modifier. Well-defined patches are controllably synthesized through area-selective deposition of silica onto the surface of seeds. After colloidal PSNPs are further modified with trimethylchlorosilane, the advancing and receding contact angles of water for PSNPs are 168 ± 2° and 167 ± 2°, respectively. The superhydrophobic and transparent coatings on the various types of substrates are obtained by a simple drop-casting procedure. Additionally, almost the same superhydrophobicity can be achieved by using colloidal PSNPs via redispersing the powder of superhydrophobic PSNPs in ethanol.

10.
Acta Chim Slov ; 63(1): 55-61, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26970789

RESUMO

Two new potentially tetradentate Schiff base ligands N'-(pyridin-2-ylmethylene)nicotinohydrazide (L1), and N'-(pyridin-2-ylmethylene)isonicotinohydrazide (L(2)) were synthesized. Reactions of hydrazone ligands L(1) and L(2) with Mn(NO(3))(2) afford two mononuclear Mn(II) complexes, [Mn(L(1))(NO(3))(H(2)O)(2)]•(NO(3)) (1) and [Mn(L(2))(2)(NO(3))(H(2)O)]•(NO(3)) (2). For complexes 1 and 2, L(1) and L(2) act as pincer-like tridentate or bidentate ligands, respectively. The Mn(II) ions in the two compounds are both in heptacoordinated environment, while the two molecules display diverse solid-state supramolecular structures because of the different orientation of Npyridine and hydrogen bonding patterns of nitrate anions. Complex 1 features 2D supramolecular sheet, while complex 2 is double-chain supramolecular structure. Both of the two complexes exhibit moderate superoxide dismutase (SOD) mimetic activity.


Assuntos
Bases de Schiff/síntese química , Superóxido Dismutase/química , Biomimética , Cristalografia por Raios X , Ligação de Hidrogênio , Bases de Schiff/química , Superóxido Dismutase/metabolismo
11.
Langmuir ; 31(48): 13214-20, 2015 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-26559375

RESUMO

Silica nanoparticle vesicles (NPVs) with encapsulating capability and surface permeability are highly attractive in nanocatalysis, biosensing, and drug delivery systems. Herein, we report the facile fabrication of silica NPVs composed of a monolayer of silica nanospheres (SNSs, ca. 15 nm in diameter) through the block copolymer-mediated self-assembly of SNSs. The silica NPVs gain different surface topographies, such as raspberry- and brain coral-like topographies, under controlled heat treatment conditions. The vesicular assembly of SNSs is successful with a series of poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) block copolymers, and the size of NPVs can be tuned by changing their molecular weight. The polymer is easily extracted from the NPVs with their colloidal dispersibility and structural integrity intact. The polymer-free silica NPVs further serve as a reaction vessel and host for functional materials such as tin oxide nanoparticles.


Assuntos
Nanosferas/química , Polímeros/química , Dióxido de Silício/química , Sistemas de Liberação de Medicamentos , Polietilenoglicóis/química , Polietilenos/química , Propriedades de Superfície
12.
Langmuir ; 31(5): 1610-4, 2015 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-25607537

RESUMO

A facile seed regrowth method is presented for the preparation of a new type of colloidal dendritic silica nanoparticles (DSNPs) with unique Konpeito-like morphology and high surface area (∼400 m(2) g(-1)). Growth of silica nanoprotrusions on the surfaces of colloidal silica nanoparticles proceeds by hydrolysis and polycondensation of tetraethoxysilane (TEOS) in the presence of a PEO-PPO-PEO-type block copolymer (Pluronic F127) under controlled pH conditions. The polymers adsorbed on the seed surface play a crucial role in the formation of DSNPs. DSNPs with controllable size (28-85 nm) and narrow size distributions can be obtained by using monodisperse silica nanoparticles with various sizes as seeds. The surface morphology of DSNPs is tunable by changing the concentration of TEOS. Additionally, novel dendritic silica nanochains are prepared using one-dimensionally assembled silica nanoparticles as the seeds.

13.
ACS Omega ; 9(18): 20142-20151, 2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38737066

RESUMO

The preparation of complex porous materials using a small molecular surfactant as the stabilizer of a high internal phase emulsion can result in harm to the environment. In this study, porous composites based on soy protein isolate with poly(acrylic acid) were prepared by in situ polymerization of a high internal phase monomer emulsion with an internal phase volume fraction of 80%. The material was prepared from acrylic acid and an N,N-methyl diacrylic acid monomer solution as the continuous phase, peanut oil as the dispersed phase, and soy protein isolate as the composite stabilizer. Scanning electron microscopy showed that porous composites exhibited a concave/convex three-dimensional interpenetrating pore structure. Fourier-transform infrared spectra revealed the existence of many active groups such as carboxyl, amino, hydroxyl, and sulfhydryl. The composite had a high adsorption capacity for lead ions, even at low concentration, with a removal rate of up to 95.7%. The adsorption process conformed to a two-stage model involving internal diffusion and Langmuir isothermal adsorption. The maximum saturated adsorption capacity was 36.71 mg/g when the initial solution concentration was 150 mg/L, the adsorbent concentration was 7.0 g/L, and the adsorption mechanism involved chemical interactions between the lead ions and the composite groups -COOH, -OH, and -SH.

14.
ISA Trans ; 144: 419-435, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37884424

RESUMO

This paper aims to improve the tracking control performance of the three-stage valve (TSV) controlled electro-hydraulic servo system (EHSS) with parameter uncertainties and other lumped unknown nonlinearities, including unknown dynamics and disturbances. A more accurate nonlinear model of the TSV-controlled EHSS is established and a neural network-based finite-time command-filtered adaptive backstepping control (NNFCABC) method is proposed for the EHSS. Adaptive control is used to deal with the system parameter uncertainties, and the radial basis function neural network (RBFNN) algorithm is introduced to approximate the lumped unknown nonlinearities. The prediction errors of serial-parallel estimation models (SPEMs) and the tracking errors are utilized together to design adaptive laws to estimate the system parameters and the weights of the RBFNNs. The entire control framework utilizes command-filtered control and backstepping techniques. By applying Levant differentiators as command filters and introducing fractional power terms into the virtual control laws and the SPEMs, the proposed NNFCABC theoretically guarantees the tracking performance of the closed-loop control system with finite-time convergence. Comparative simulations and experiments verify the feasibility and superiority of the proposed control scheme.

15.
Hortic Res ; 11(6): uhae096, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38855415

RESUMO

Cold stress significantly limits the yield and quality of tomato. Deciphering the key genes related to cold tolerance is important for selecting and breeding superior cold-tolerant varieties. γ-aminobutyric acid (GABA) responds to various types of stress by rapidly accumulating in plant. In this study, glutamic acid decarboxylase (GAD2) was a positive regulator to enhance cold stress tolerance of tomato. Overexpression of SlGAD2 decreased the extent of cytoplasmic membrane damage and increased the endogenous GABA content, antioxidant enzyme activities, and reactive oxygen species (ROS) scavenging capacity in response to cold stress, whereas Slgad2 mutant plants showed the opposite trend. In addition, SlGAD2 induced anthocyanin biosynthesis in response to cold stress by increasing the content of endogenous GABA. Further study revealed that SlGAD2 expression was negatively regulated by the transcription factor SlTHM27. However, the transcript levels of SlTHM27 were repressed under cold stress. Antioxidant enzyme activities, SlGAD2 transcript levels, GABA and anthocyanin contents were significantly increased in Slthm27 mutant plants. Further, our study demonstrated that SlTHM27 decreases SlGAD2-promoted cold resistance in tomato by repressing SlGAD2 transcription. Overall, our results showed that the SlTHM27-SlGAD2 model regulates the cold tolerance in tomato by regulating GABA and anthocyanin.

16.
Obesity (Silver Spring) ; 31(5): 1270-1279, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36815242

RESUMO

OBJECTIVE: Novel antiobesity treatments are highly effective in recent clinical trials. Access to these medications is needed to supplement lifestyle and surgical interventions for millions living with obesity worldwide, but high prices are limiting. This study aimed to review current treatment costs and calculate potential estimated minimum prices (EMPs). METHODS: The authors searched national drug price databases across various countries for orlistat, naltrexone-bupropion, topiramate-phentermine, liraglutide, semaglutide, and tirzepatide. EMPs for antiobesity medications were calculated using established methodology, using active pharmaceutical ingredients (API) from the Panjiva database. EMPs were calculated per 30-day course and include costs of active pharmaceutical ingredients, excipients, formulation, taxation, and 10% profit margin. RESULTS: National prices of antiobesity medications were significantly higher than calculated EMPs. Semaglutide 30-day course prices ranged from $804 (United States) to $95 (Turkey) while the EMP was $40. Liraglutide prices ranged from $1418 (United States) to $252 (Norway) while the EMP was $50. Some oral treatments could be generically manufactured at very low costs per course ($7 for orlistat; $5 for phentermine/topiramate combination tablets), while naltrexone/bupropion was more expensive ($54). CONCLUSIONS: This study shows that certain weight loss treatments can be manufactured and sold profitably at low costs, but prices currently range widely between countries, limiting access for those in need.


Assuntos
Fármacos Antiobesidade , Liraglutida , Orlistate/uso terapêutico , Topiramato , Liraglutida/uso terapêutico , Naltrexona/uso terapêutico , Bupropiona/uso terapêutico , Combinação de Medicamentos , Fármacos Antiobesidade/uso terapêutico , Fentermina/uso terapêutico , Custos de Cuidados de Saúde , Acessibilidade aos Serviços de Saúde
17.
Langmuir ; 28(37): 13181-8, 2012 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-22934598

RESUMO

The effects of polymers on the one-dimensional assembly of silica nanospheres (SNSs) in the liquid phase are systematically investigated using nonionic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (abbreviated as PEO-PPO-PEO) triblock copolymers with varying hydrophilic-lipophilic balance (HLB) values. Scanning electron microscopy is employed for morphological observations of the polymer-mediated assemblies of SNSs on the basis of which the optimal pH for 1D assembly (pH(1D)) is determined. To clarify the polymers' effects on the 1D assembly of SNSs, the relationships between pH(1D) and polymers' HLB values, the numbers of hydrophilic EO and hydrophobic PO units, and the relative ratio of N(PO)/N(EO) are examined. Zeta potential measurements are conducted to investigate the electrostatic repulsion among the SNSs in the presence of block copolymers. It is found that the relative hydrophilicity of the block copolymers greatly affects the balance of interactions in the 1D assembly of SNSs. Block copolymers with large HLB values promote the 1D assembly of SNSs under near-neutral pH conditions, whereas the block copolymers with small HLB values promote 1D assembly under basic pH conditions. Therefore, the 1D assembly of SNSs is achieved over an extensive pH range (7.5-9.5) through the employment of block copolymers of different hydrophilic and hydrophobic block lengths.


Assuntos
Nanosferas/química , Polietilenoglicóis/química , Propilenoglicóis/química , Dióxido de Silício/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Estrutura Molecular , Tamanho da Partícula , Propriedades de Superfície
18.
ISA Trans ; 131: 628-638, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35659455

RESUMO

This work presents a dynamic posture tracking control strategy for wheel-legged systems on uneven surfaces. Based on the kinematic model of a wheel-legged robotic system, the expected positions for the end-effectors of wheel-legs are calculated according to posture references and sensor feedback. The position control problem for a general wheel-leg is investigated for the active mechanism to imitate a passive suspension and respond to the external contact forces. The position tracking accuracy of the wheel-leg is sacrificed to enhance the compliance performance under rough terrain. Because of the unique contact state with the uneven ground for each wheel-leg, the position responses are different. As a result, the forces from the wheel-legs to the fuselage are inconsistent, which leads to the risk of posture oscillations. Equipping the wheel-legs with an undirected communication network, a consensus scheme for the robotic system is developed with proven global asymptotic stability to improve the posture tracking property. A novel robotic system is established with Stewart-structured wheel-legs, which are connected by a user datagram protocol network. Comparative experimental results are carried out on the physical prototype to validate the effectiveness of the proposed approach.


Assuntos
Equilíbrio Postural , Postura , Postura/fisiologia , Fenômenos Biomecânicos , Gravitação , Modalidades de Fisioterapia
19.
Open Forum Infect Dis ; 9(1): ofab581, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34988252

RESUMO

BACKGROUND: Currently, only dexamethasone, tocilizumab, and sarilumab have conclusively been shown to reduce mortality of coronavirus disease 2019 (COVID-19). Safe and effective treatments will need to be both affordable and widely available globally to be used alongside vaccination programs. This analysis will estimate and compare potential generic minimum costs of a selection of approved COVID-19 drug candidates with available international list prices. METHODS: We searched for repurposed drugs that have been approved by at least one of the World Health Organization, US Food and Drug Administration, or the United Kingdom National Institute of Health and Care Excellence organizations or at least given emergency use authorization or recommended for off-label prescription. Drug prices were searched for dexamethasone, budesonide, baricitinib, tocilizumab, casirivimab, and imdevimab, and sarilumab, using active pharmaceutical ingredients (APIs) data extracted from global shipping records. This was compared with national pricing data from a range of low-, medium-, and high-income countries. Annual API export volumes from India were used to estimate the current availability of each drug. RESULTS: Repurposed therapies can be generically manufactured for some treatments at very low per-course costs, ranging from US $2.58 for intravenous (IV) dexamethasone (or US $0.19 orally) and US $4.34 for inhaled budesonide. No export price data were available for baricitinib, tocilizumab, casirivimab, and imdevimab, or sarilumab, but courses of these treatments have higher prices, ranging from US $6.67 for baricitinib to US $875.5 for sarilumab. When comparing international list prices, we found wide variations between countries. CONCLUSIONS: Successful management of COVID-19 will require equitable access to treatment for all populations, not just those able to pay high prices. Dexamethasone and budesonide are widely available and affordable, whereas monoclonal antibodies and IV treatment courses are more expensive.

20.
Open Forum Infect Dis ; 9(9): ofac174, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36176569

RESUMO

Pfizer and the Medicines Patent Pool (MPP) have reached a voluntary licensing agreement for Paxlovid (nirmatrelvir+ritonavir), a novel antiviral for coronavirus disease 2019 (COVID-19) taken orally in the first 5 days from symptom onset. The Pfizer-MPP deal enables 95 low- and middle-income countries (L/MICs) to access affordable biosimilars. Generics are delayed awaiting bioequivalence testing and may be ineffective in L/MICs with reduced testing capacity, which comprise only 10% of global diagnoses. Thirty-nine percent of diagnoses originate in MICs forced to pay high prices due to exclusion from the Pfizer-MPP deal. The cost-effectiveness of Paxlovid could be limited compared with the creation of sustainable vaccine infrastructure in these nations, delaying socioeconomic pandemic recovery. Furthermore, Paxlovid may not be cost-effective in vaccinated populations, and concerns remain over ritonavir drug interactions with COVID-19 comorbidity medications. We call for expanded coverage by the Paxlovid-MPP deal and greater access to testing.

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