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1.
Micromachines (Basel) ; 15(3)2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38542607

RESUMO

To mitigate the impact of low-frequency noise from the tunnel magnetoresistance (TMR) current sensor and ambient stray magnetic fields on weak current detection accuracy, we propose a high-resolution modulation-demodulation test method. This method modulates and demodulates the measurement signal, shifting low-frequency noise to the high-frequency band for effective filtering, thereby isolating the target signal from the noise. In this study, we developed a Simulink model for the TMR current sensor modulation-demodulation test method. Practical time-domain and frequency-domain tests of the developed high-resolution modulation-demodulation method revealed that the TMR current sensor exhibits a nonlinearity as low as 0.045%, an enhanced signal-to-noise ratio (SNR) of 77 dB, and a heightened resolution of 100 nA. The findings indicate that this modulation-demodulation test method effectively reduces the impact of low-frequency noise on TMR current sensors and can be extended to other types of resistive devices.

2.
Environ Pollut ; 348: 123893, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38556146

RESUMO

Below the boundary layer, the air pollutants have been confirmed to present the decreasing trend with the height in most situaitons. However, the disperiosn rate of air pollutants in the vertical profile is rarely investigated in detail, especially through in-situ measurement. With this consideration, we employed an unmanned aerial vehicle equipped with portable monitoring equipments to scrutinize the vertical distribution of PM2.5. Based on the original data, we found that PM2.5 concentration decreases gradually with altitude below the boundary layer and demonstrated an obvious linear correlation. Therefore, the vertical distribution of PM2.5 was quantified by representing the distribution of PM2.5 with the slope of PM2.5 vertical distribution. We used backward trajectories to reveal the causes of outliers (PM2.5 increasing with altitude), and found that PM2.5 in the high altitude came from the southwest. Besides, the relationship between the vertical distribution of PM2.5 and various meteorological factors was investigated using stepwise regression analysis. The results show that the four meteorological factors most strongly correlated with the slope values are: (a) the difference in relative humidity between the ground and the air; (b) the difference in temperature between the ground and the air; (c) the height of the boundary layer; and (d) the wind speed. The slope values increase with increasing the difference in relative humidity between ground and air and the difference in temperature between the ground and the air, and decrease with increasing boundary layer height and wind speed. According to the Random Forest calculations, the ground-to-air relative humidity difference is the most important at 0.718; the wind speed is the least important at 0.053; and the ground-to-air temperature difference and boundary layer height are 0.140 and 0.088, respectively.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Material Particulado/análise , Dispositivos Aéreos não Tripulados , Monitoramento Ambiental/métodos , Poluentes Atmosféricos/análise , Vento , Poluição do Ar/análise , China
3.
ACS Nano ; 18(6): 4651-4682, 2024 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-38307615

RESUMO

MXenes have shown great potential for micro-supercapacitors (MSCs) due to the high metallic conductivity, tunable interlayer spacing and intercalation pseudocapacitance. In particular, the negative surface charge and high hydrophilicity of MXenes make them suitable for various solution processing strategies. Nevertheless, a comprehensive review of solution processing of MXene MSCs has not been conducted. In this review, we present a comprehensive summary of the state-of-the-art of MXene MSCs in terms of ink rheology, microelectrode design and integrated system. The ink formulation and rheological behavior of MXenes for different solution processing strategies, which are essential for high quality printed/coated films, are presented. The effects of MXene and its compounds, 3D electrode structure, and asymmetric design on the electrochemical properties of MXene MSCs are discussed in detail. Equally important, we summarize the integrated system and intelligent applications of MXene MSCs and present the current challenges and prospects for the development of high-performance MXene MSCs.

4.
Int Braz J Urol ; 50(1): 7-19, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38166218

RESUMO

PURPOSE: This study aims to evaluate the safety and efficacy of ultrasound-guided balloon dilation compared to non-balloon dilation for percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: A systematic review and meta-analysis were conducted by searching PubMed, EMBASE, and the Cochrane Library. Results were filtered using predefined inclusion and exclusion criteria as described and meta-analysis was performed using Review Manager 5.4 software. RESULTS: A total of six studies involving 1189 patients who underwent PCNL were included. The meta-analysis results demonstrated that compared to non-balloon dilation, balloon dilation was associated with reduced haemoglobin drop [mean difference (MD) = -0.26, 95% CI = -0.40 ~ -0.12, P = 0.0002], decreased transfusion rate [odds ratio (OR) = 0.47, 95% CI = 0.24 ~ 0.92, P = 0.03], shorter tract establishment time (MD = -1.30, 95% CI = -1.87 ~ -0.72, P < 0.0001) and shorter operation time (MD = -5.23, 95% CI = -10.19 ~ -0.27, P = 0.04). CONCLUSIONS: Overall, ultrasound-guided balloon dilatation offered several advantages in PCNL procedures. It facilitated faster access establishment, as evidenced by shorter access creation time. Additionally, it reduced the risk of kidney injury by minimizing postoperative haemoglobin drop and decreasing the need for transfusions. Moreover, it enhanced the efficiency of surgery by reducing the operation time. However, it is important to note that the quality of some included studies was subpar, as they did not adequately control for confounding factors that may affect the outcomes. Therefore, further research is necessary to validate and strengthen these findings.


Assuntos
Cálculos Renais , Nefrolitotomia Percutânea , Nefrostomia Percutânea , Humanos , Nefrolitotomia Percutânea/métodos , Dilatação , Rim , Cálculos Renais/cirurgia , Ultrassonografia de Intervenção , Hemoglobinas , Nefrostomia Percutânea/métodos , Resultado do Tratamento
5.
Chem Rec ; 23(12): e202300275, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37772656

RESUMO

Over the past decades, asymmetric photochemical synthesis has garnered significant attention for its sustainability and unique ability to generate enantio-enriched molecules through distinct reaction pathways. Photochemical asymmetric three-component reactions have demonstrated significant potential for the rapid construction of chiral compounds with molecular diversity and complexity. However, noteworthy challenges persist, including the participation of high-energy intermediates such as radical species, difficulties in precise control of stereoselectivity, and the presence of competing background and side reactions. Recent breakthroughs have led to the development of sophisticated strategies in this field. This review explores the intricate mechanisms, synthetic applications, and limitations of these methods. We anticipate that it will contribute towards advancing asymmetric catalysis, photochemical synthesis, and green chemistry.

6.
BMC Urol ; 23(1): 130, 2023 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-37525149

RESUMO

BACKGROUND: Cystinuria and xanthinuria are both rare genetic diseases involving urinary calculi. However, cases combining these two disorders have not yet been reported. CASE PRESENTATION: In this study, we report a case of cystinuria with xanthine stones and hyperuricemia. The 23-year-old male patient was diagnosed with kidney and ureteral stones, solitary functioning kidney and hyperuricemia after admission to the hospital. The stones were removed by surgery and found to be composed of xanthine. CONCLUSION: Genetic testing by next-generation sequencing technology showed that the patient carried the homozygous nonsense mutation c.1113 C> A (p.Tyr371*) in the SLC3A1 gene, which was judged to be a functionally pathogenic variant. Sanger sequencing revealed that the patient's parents carried this heterozygous mutation, which is a pathogenic variant that can cause cystinuria. The 24-h urine metabolism analysis showed that the cystine content was 644 mg (<320 mg/24 h), indicating that the patient had cystinuria, consistent with the genetic test results. This case shows that cystinuria and xanthine stones can occur simultaneously, and provides evidence of a possible connection between the two conditions. Furthermore, our findings demonstrate the potential value of genetic testing using next-generation sequencing to effectively assist in the clinical diagnosis and treatment of patients with urinary calculi.


Assuntos
Sistemas de Transporte de Aminoácidos , Cistinúria , Humanos , Masculino , Adulto Jovem , Cistinúria/genética , Sistemas de Transporte de Aminoácidos/genética , Xantina , Cálculos Renais , Hiperuricemia , Códon sem Sentido , Testes Genéticos , Linhagem , Feminino
7.
PLoS One ; 18(4): e0283932, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37023092

RESUMO

Real-time and accurate detection of ships plays a vital role in ensuring navigation safety and ship supervision. Aiming at the problems of large parameters, large computation quantity, poor real-time performance, and high requirements for memory and computing power of the current ship detection model, this paper proposes a ship target detection algorithm MC-YOLOv5s based on YOLOv5s. First, the MobileNetV3-Small lightweight network is used to replace the original feature extraction backbone network of YOLOv5s to improve the detection speed of the algorithm. And then, a more efficient CNeB is designed based on the ConvNeXt-Block module of the ConvNeXt network to replace the original feature fusion module of YOLOv5s, which improves the spatial interaction ability of feature information and further reduces the complexity of the model. The experimental results obtained from the training and verification of the MC-YOLOv5s algorithm show that, compared with the original YOLOv5s algorithm, MC-YOLOv5s reduces the number of parameters by 6.98 MB and increases the mAP by about 3.4%. Even compared with other lightweight detection models, the improved model proposed in this paper still has better detection performance. The MC-YOLOv5s has been verified in the ship visual inspection and has great application potential. The code and models are publicly available at https://github.com/sakura994479727/datas.


Assuntos
Navios , Navegação Espacial , Algoritmos , Exame Físico
8.
J Chem Phys ; 158(10): 104703, 2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36922126

RESUMO

MXenes have shown great potential as an emerging two-dimensional (2D) material for micro-supercapacitors (MSCs) due to their high conductivity, rich surface chemistry, and high capacity. However, MXene sheets inherently tend to lay flat on the substrate during film formation to assemble into compact stacked structures, which hinders ion accessibility and prolongs ion transport paths, leading to highly dependent electrochemical properties on the thickness of the film. Here, we demonstrate a vertically aligned Ti3C2Tx MXene based micro-supercapacitor with an excellent electrochemical performance by a liquid nitrogen-assisted freeze-drying method. The vertical arrangement of the 2D MXene sheets allows for directional ion transport, enabling the vertical-MXene based MSCs to exhibit thickness-independent electrochemical properties even in thick films. In addition, the MSCs displayed a high areal capacitance of 87 mF cm-2 at 10 mV s-1 along with an excellent stability of ∼87.4% after 10 000 charge-discharge cycles. Furthermore, the vertical-MXene approach proposed here is scalable and can be extended to other systems involving directional transport.

9.
Small ; 19(16): e2207947, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36651008

RESUMO

The interfacial effect is widely used to optimize the properties of ferroelectric nanocomposites, however, there is still a lack of direct evidence to understand its underlying mechanisms limited by the nano size and complex structures. Here, taking piezoelectricity, for example, the mechanism of interfacial polarization in barium titanate/poly(vinylidene fluoride-ran-trifluoroethylene) (BTO/P(VDF-TrFE)) nanocomposite is revealed at multiple scales by combining Kelvin probe force microscope (KPFM) with theoretical stimulation. The results prove that the mismatch of permittivity between matrix and filler leads to the accumulation of charges, which in turn induces local polarization in the interfacial region, and thus can promote piezoelectricity independently. Furthermore, the strategy of interfacial polarization to enhance piezoelectricity is extended and validated in other two similar nanocomposites. This work uncovers the mechanism of interfacial polarization and paves newfangled insights to boost performances in ferroelectric nanocomposites.

10.
Ren Fail ; 45(1): 2158870, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36637005

RESUMO

INTRODUCTION: The aim of this study was to evaluate the association between recurrence-free survival (RFS) and perirenal fat thickness (PFT) in a cohort of Chinese population with unilateral nephrolithiasis. METHODS: We retrospectively reviewed the medical records of 81 patients with unilateral nephrolithiasis in our center from January 2019 to June 2019. PFT measured on computed tomography (CT) scans was evaluated. Kaplan-Meier curves and log-rank tests were used to assess significant differences in RSF between high-PFT and low-PFT groups within sexes. Univariable and multivariable Cox regression analyses were used to evaluate the potential risk factors for renal stone recurrence. RESULTS: High PFT was significantly associated with high BMI and hyperlipidemia (p = .003 and.047, respectively). The PFT of stone-bearing kidney was significantly greater than PFT of non-stone-bearing kidney (0.77 ± 0.60 cm vs. 0.67 ± 0.58 cm, p = .002) . During the follow-up periods (median 31 months), 21 (25.9%) patients experienced ipsilateral renal stone recurrence. In addition, Kaplan-Meier survival curves showed that patients with low PFT had a significant better RFS than those with high PFT (p = .012). In the univariable Cox analyses, male sex and high PFT were significantly associated with a poor RFS (p = .042 and .018, respectively). Moreover, both male sex and high PFT retained significance in the multivariable analyses (p = .045 and .020, respectively). CONCLUSIONS: Our findings suggested that PFT is a noninvasive and feasible parameter, which may help in the risk stratification of renal stone recurrence in the follow-up periods.


Assuntos
Cálculos Renais , Nefrolitíase , Humanos , Masculino , População do Leste Asiático , Rim , Cálculos Renais/diagnóstico por imagem , Cálculos Renais/epidemiologia , Nefrolitíase/diagnóstico por imagem , Nefrolitíase/epidemiologia , Obesidade , Recidiva , Estudos Retrospectivos , Fatores de Risco , China
11.
Eur J Pediatr ; 182(4): 1469-1482, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36705723

RESUMO

The purpose of this study is to synthesize evidence on risk factors associated with newborn 31-day unplanned hospital readmissions (UHRs). A systematic review was conducted searching CINAHL, EMBASE (Ovid), and MEDLINE from January 1st 2000 to 30th June 2021. Studies examining unplanned readmissions of newborns within 31 days of discharge following the initial hospitalization at the time of their birth were included. Characteristics of the included studies examined variables and statistically significant risk factors were extracted from the inclusion studies. Extracted risk factors could not be pooled statistically due to the heterogeneity of the included studies. Data were synthesized using content analysis and presented in narrative and tabular form. Twenty-eight studies met the eligibility criteria, and 17 significant risk factors were extracted from the included studies. The most frequently cited risk factors associated with newborn readmissions were gestational age, postnatal length of stay, neonatal comorbidity, and feeding methods. The most frequently cited maternal-related risk factors which contributed to newborn readmissions were parity, race/ethnicity, and complications in pregnancy and/or perinatal period. CONCLUSION: This systematic review identified a complex and diverse range of risk factors associated with 31-day UHR in newborn. Six of the 17 extracted risk factors were consistently cited by studies. Four factors were maternal (primiparous, mother being Asian, vaginal delivery, maternal complications), and two factors were neonatal (male infant and neonatal comorbidities). Implementation of evidence-based clinical practice guidelines for inpatient care and individualized hospital-to-home transition plans, including transition checklists and discharge readiness assessments, are recommended to reduce newborn UHRs. WHAT IS KNOWN: • Attempts have been made to identify risk factors associated with newborn UHRs; however, the results are inconsistent. WHAT IS NEW: • Six consistently cited risk factors related to newborn 31-day UHRs. Four maternal factors (primiparous, mother being Asian, vaginal delivery, maternal complications) and 2 neonatal factors (male infant and neonatal comorbidities). • The importance of discharge readiness assessment, including newborn clinical fitness for discharge and parental readiness for discharge. Future research is warranted to establish standardised maternal and newborn-related variables which healthcare providers can utilize to identify newborns at greater risk of UHRs and enable comparison of research findings.


Assuntos
Mães , Readmissão do Paciente , Lactente , Gravidez , Feminino , Recém-Nascido , Humanos , Masculino , Fatores de Risco , Paridade , Alta do Paciente , Tempo de Internação
12.
Biosens Bioelectron ; 222: 114999, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36521206

RESUMO

Electronic textiles are fundamentally changing the way we live. However, the inability to effectively recycle them is a considerable burden to the environment. In this study, we developed a cotton fiber-based piezoresistive textile (CF p-textile) for biomonitoring which is biocompatible, biodegradable, and environmentally friendly. These CF p-textiles were fabricated using a scalable dip-coating method to adhere MXene flakes to porous cotton cellulose fibers. The adhesion is made stronger by strong hydrogen bonding between MXene flakes and hierarchically porous cotton cellulose fibers. This cotton-fiber system provides a high sensitivity of 17.73 kPa-1 in a wide pressure range (100 Pa-30 kPa), a 2 Pa subtle pressure detection limit, fast response/recovery time (80/40 ms), and good cycle stability (over 5, 000 cycles). With its compelling sensing performance, the CF p-textile can detect various human biomechanical activities, including pulsation, muscle movement, and swallowing, while still being comfortable to wear. Moreover, the cotton cellulose is decomposed into low-molecular weight cellulose or glucose as a result of the 1,4-glycosidic bond breakage when exposed to acid or during natural degradation, which allows the electronic textile to be biodegradable. This work offers an ecologically-benign, cost-effective and facile approach to fabricating high-performance wearable bioelectronics.


Assuntos
Técnicas Biossensoriais , Dispositivos Eletrônicos Vestíveis , Humanos , Fibra de Algodão , Monitoramento Biológico , Têxteis , Celulose
13.
PLoS One ; 17(3): e0264192, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35294440

RESUMO

The wide usage of 3D mesh models greatly increases the importance of an effective matching algorithm for them. In this paper, we propose a novel 3D model matching algorithm. Firstly, vertices on the input 3D mesh models are mapped to 1D space by employing Isomap. A pose-invariant feature set is then constructed from the vertices in 1D space. Finally, the similarity between any two 3D models can be computed by comparing their feature sets. Experimental results show that the algorithm is not only invariant to translation, rotation, scaling, but also invariant to different poses of 3D models. Additionally, the algorithm is robust to noise.


Assuntos
Algoritmos , Rotação
14.
ACS Nano ; 16(3): 3776-3784, 2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35239314

RESUMO

MXene-based microsupercapacitors (MSCs) have promoted the development of on-chip energy storage for miniaturized and portable electronics due to the small size, high power density and integration density. However, restricted energy density and operating voltage invariably create obstacles to the practical application of MSCs. Here, we report a symmetric MXene-based on-chip MSC, achieving an ultrahigh energy density of 75 mWh cm-3 with high operating voltage of 1.2 V, which are almost the highest values among all reported symmetric MXene MSCs. The adjustment strategy of acetone on the viscosity and surface tension of MXene ink, along with the natural sedimentation strategy, can effectively prevent the orderly stacking of MXene sheets. Further, we developed an all-in-one Si-electronics with three series MSCs through laser-etching technology, obviously presenting high integration capacity and processing compatibility. Thus, this work will contribute to the development of high integration all-in-one electronics with high energy density MXene-based MSCs.

15.
Environ Pollut ; 292(Pt B): 118464, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34763019

RESUMO

The use of biomass for cooking and heating is considered an important factor associated with chronic obstructive pulmonary disease (COPD), but few studies have previously addressed its underlying mechanisms. Therefore, this research aimed to evaluate the effects of biomass-related PM2.5 (BRPM2.5) exposure on 16HBE human airway epithelial cells and in mice with regard to mitochondrial dysfunction. Our study indicated that BRPM2.5 exposure of 16HBE cells resulted in mitochondrial dysfunction, including decreased mitochondrial membrane potential, increased expression of fission proteins-phospho-DRP1, increased mitochondrial ROS (mtROS), and decreased levels of ATP. BRPM2.5 altered the mitochondrial metabolism of 16HBE cells by decreasing mitochondrial oxygen consumption and glycolysis. However, Mitochondria targeted peptide SS-31 eliminated mitochondrial ROS and alleviated the ATP deficiency and proinflammatory cytokines release. BRPM2.5 exposure resulted in abnormal mitochondrial morphological alterations both in 16HBE and in lung tissue. Taken together, these results suggest that BRPM2.5 has detrimental effects on human airway epithelial cells, leading to mitochondrial dysfunction, abnormal mitochondrial metabolism and altered mitochondrial dynamics. The present study provides the first evidence that disruption of mitochondrial structure and mitochondrial metabolism may be one of the mechanisms of BRPM2.5-induced respiratory dysfunction.


Assuntos
Células Epiteliais , Pulmão , Animais , Biomassa , Humanos , Pulmão/química , Camundongos , Material Particulado/análise , Material Particulado/toxicidade , Espécies Reativas de Oxigênio
16.
Org Lett ; 24(1): 328-333, 2022 01 14.
Artigo em Inglês | MEDLINE | ID: mdl-34958584

RESUMO

Chemo- and regioselectively nickel-catalyzed reductive benzylarylation of unactivated alkenes with o-bromobenzyl chlorides is disclosed herein, in which electrophiles participate through a single-component double-site approach. Moreover, its utility is underscored by the concise synthesis of bioactive Indane compounds and postreaction functionalizations leading to structurally diverse scaffolds. Preliminary mechanistic investigations suggest a radical chain reaction mechanism.

17.
Small ; 17(25): e2100956, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34018685

RESUMO

Printed electronics are expected to facilitate the widespread distributed wearable electronics in the era of the Internet of things. However, developing cheap and stable electrode inks remains a significant challenge in the printed electronics industry and academic community. Here, overcoming the weak hydrophilicity of polyaniline, a low-cost, easy-fabricating, and air-stable conducting polymer (CP) ink is devised through a facile assemble-disperse strategy delivering a high conductivity in the order of 10-2 S cm-1 along with a remarkable specific capacitance of 386.9 F g-1 at 0.5 A g-1 (dehydrated state). The additive-free CP ink is directly employed to print wearable micro-supercapacitors (MSCs) via the spray-coating method, which deliver a high areal capacitance (96.6 mF cm-2 ) and volumetric capacitance (26.0 F cm-3 ), outperforming most state-of-the-art CP-based supercapacitors. This work paves a new approach for achieving scalable MSCs, thus rendering a cost-effective, environmentally friendly, and pervasive energy solution for next-generation distributed electronics.


Assuntos
Tinta , Dispositivos Eletrônicos Vestíveis , Condutividade Elétrica , Eletrônica , Polímeros
18.
Curr Med Sci ; 41(1): 140-144, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33582918

RESUMO

The effect of preoperative Double-J (DJ) ureteral stenting before flexible ureterorenoscopy (FURS) in the treatment for urinary stones was evaluated. We retrospectively enrolled 306 consecutive patients who underwent FURS from Jan. 2014 to Dec. 2017. All the patients were classified into two groups according to whether they had DJ ureteral stenting before FURS. Baseline characteristics (age, sex, stone location, stone size, surgical success rate, operation time, stone-free rate of the first day after surgery, stone-free rate of the first month after surgery, total complication rate) were compared using Chi-square test for categorical variables and Kruskal-Wallis test for continuous variables. In total, 306 patients were included in this study. The group of DJ stenting before FURS included 203 (66.3%) patients, and non-DJ stenting before FURS was observed in 103 (33.7%) patients. The group of DJ stenting before FURS was significantly associated with a shorter operation time (53.8 vs. 59.3 min, P<0.001), a higher stone-free rate of the first day after surgery (69.0% vs. 51.5%, P=0.003). However, statistical significant differences were not found in the age, sex, stone location, stone size, surgical success rate, stone-free rate of the first month after surgery (89.2% vs. 81.6%, P=0.065) and total complication rate (5.4% vs. 9.7%, P=0.161) between the two groups. Preoperative DJ ureteral stenting before FURS could reduce the operation time and increase stone-free rate of the first day after surgery. However, it might not benefit the stone-free rate of the first month after surgery and reduce the complication rate. Preoperative DJ stenting should be not routinely performed.


Assuntos
Complicações Pós-Operatórias/epidemiologia , Ureteroscopia/métodos , Cálculos Urinários/cirurgia , Cateterismo Urinário/métodos , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Período Pré-Operatório , Ureteroscopia/efeitos adversos , Cateterismo Urinário/efeitos adversos , Cateterismo Urinário/instrumentação , Cateteres Urinários/efeitos adversos , Cateteres Urinários/normas
19.
ACS Appl Mater Interfaces ; 13(5): 6339-6348, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33502153

RESUMO

High electrical conductivity and all-open microstructure characteristics intrinsically endow both graphene and MXenes with superior electrochemical energy storage capability. However, the above two-dimensional (2D) thicker electrodes (>20 µm) severely dilute their unique rapid electronic-ionic transferring characteristic, posing a paradox of high gravimetric and high volumetric capacitive properties due to massively excessive macropores or an unduly restacked issue. Herein, we elaborately construct novel monolithic NH2-graphene and Ti3C2Tx MXene (NG@MX) composites through dual-functional induced self-assembly with the help of both covalent and hydrogen bonding interactions. Notably, much thicker monolithic NG@MX electrodes (>90 µm) fabricated by a conventional roll-coating method without any further compaction treatment can simultaneously deliver two times gravimetric (gra.) and volumetric (vol.) performance than those of pure graphene (in vol.) or MXene (in gra.) materials. Moreover, monolithic NG@MX-based supercapacitors can remarkably present two times energy density as that of graphene and four times as MXene, respectively. Such greatly enhanced electrochemical properties are closely related to the appropriate equilibrium of the volumetric density and the open structure, which can effectively guarantee the rapid transfer of both electrons and ions in the thick monolithic NG@MX electrodes. Undoubtedly, dual-functional chemical bonding-induced self-constructing NG@MX monoliths efficiently solve the long-existing gra. and vol. capacitive paradox of the thicker 2D materials used in supercapacitors, which will guide the design of high-performance capacitive materials and promote their practical application in electrochemical energy storage.

20.
Nat Nanotechnol ; 15(10): 836-840, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32807877

RESUMO

Understanding charge transport in DNA molecules is a long-standing problem of fundamental importance across disciplines1,2. It is also of great technological interest due to DNA's ability to form versatile and complex programmable structures. Charge transport in DNA-based junctions has been reported using a wide variety of set-ups2-4, but experiments so far have yielded seemingly contradictory results that range from insulating5-8 or semiconducting9,10 to metallic-like behaviour11. As a result, the intrinsic charge transport mechanism in molecular junction set-ups is not well understood, which is mainly due to the lack of techniques to form reproducible and stable contacts with individual long DNA molecules. Here we report charge-transport measurements through single 30-nm-long double-stranded DNA (dsDNA) molecules with an experimental set-up that enables us to address individual molecules repeatedly and to measure the current-voltage characteristics from 5 K up to room temperature. Strikingly, we observed very high currents of tens of nanoamperes, which flowed through both homogeneous and non-homogeneous base-pair sequences. The currents are fairly temperature independent in the range 5-60 K and show a power-law decrease with temperature above 60 K, which is reminiscent of charge transport in organic crystals. Moreover, we show that the presence of even a single discontinuity ('nick') in both strands that compose the dsDNA leads to complete suppression of the current, which suggests that the backbones mediate the long-distance conduction in dsDNA, contrary to the common wisdom in DNA electronics2-4.


Assuntos
DNA/química , Condutividade Elétrica , Ouro/química , Nanoestruturas/química , Pareamento de Bases , Dimerização , Eletrônica , Elétrons , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Modelos Moleculares , Nanoestruturas/ultraestrutura , Conformação de Ácido Nucleico
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