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1.
ACS Sens ; 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32181650

RESUMO

For the first time, a reproducible surface-plasmon-enhanced optical sensor for the detection of gaseous formaldehyde was proposed by depositing the mixture of CdSe@ZnS quantum dots (QDs), fumed silica (FS) and gold nanoparticles (GNs) on the surface of silica spheres array to meet the urgent requirement of a rapid, sensitive, and highly convenient formaldehyde detection method. Due to the spectra overlap between QDs and GNs, plasmon-enhanced fluorescence was observed in the film of QDs/FS/GNs. When exposing to formaldehyde molecules, the enhanced fluorescence was quenched linearly with the increase of formaldehyde concentration in the range of 0.5-2.0 ppm. The reason is attributed to the nonradiative electron transfer from QDs to the carbonyl of formaldehyde molecules with the assistance of amino groups. Our results demonstrate that the designed sensors are capable of detecting ultralow concentration gaseous formaldehyde at room temperature with a fast response-recovery time, excellent selectivity, stability and reproducibility. This work provides a simple and low-cost approach for optical formaldehyde sensor fabrication and shows promising applications in environmental detection.

2.
Phys Chem Chem Phys ; 22(2): 914-918, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31845940

RESUMO

As a representative in-plane anisotropic two-dimensional (2D) material, germanium monoselenide (GeSe) has attracted considerable attention recently due to its various in-plane anisotropic material properties originating from the low symmetry of a puckered honeycomb structure. Although there have been plenty of reports on the in-plane anisotropic vibrational, electrical and optical properties of GeSe, the strain effect on those appealing anisotropies is still under exploration. Here we report a systematic first-principles computational investigation of strain-engineering of the anisotropic electronic properties of GeSe monolayers. We found that the anisotropic ratio of the effective mass and mobility of charge carriers (electrons and holes) of GeSe along two principle axes can be controlled by using simple strain conditions. Notably, the preferred conducting direction of GeSe can be even rotated by 90° under an appropriate uniaxial strain (>5%). Such effective strain modulation of the electronic anisotropy of GeSe monolayers provides them abundant opportunities for future mechanical-electronic devices.

3.
Biomed Res Int ; 2019: 4128315, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31815137

RESUMO

This study is to identify the circular RNA (circRNA) expression profile that is functionally related to pancreatic islet ß-cell autophagy and their potential regulation mechanisms in type 2 diabetes mellitus (T2DM). T2DM rat model was constructed by administration of high-fat and high-sugar diet. ß-cells were isolated from islets by flow cytometry. CircRNA expression profile in ß-cells was detected by circRNA microarrays, and the differentially expressed circRNAs were identified and validated by qRT-PCR. MicroRNA (miRNA) target prediction software and multiple bioinformatic approaches were used to construct a map of circRNA-miRNA interactions for the differentially expressed circRNAs. A total of 825 differentially expressed circular transcripts were identified in T2DM rats compared with control rats, among which 388 were upregulated and 437 were downregulated. Ten circRNAs were identified to have significant differences by qRT-PCR. GO analysis enriched terms such as organelle membrane and protein binding and the top enriched pathways for the circRNAs included MAPK signaling pathway. The differentially expressed circRNAs might involve in MAPK signaling pathway, apoptosis, and Ras signaling pathway. We speculate that these circRNAs, especially rno_circRNA_008565, can regulate the autophagy of islet ß-cells via interactions with miRNA. Dysregulation of several circRNAs may play a role in T2DM development, and rno_circRNA_008565 may be a potential regulator of ß-cell autophagy.

4.
J Am Chem Soc ; 141(45): 18075-18082, 2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31638806

RESUMO

Defect passivation using oxygen has been identified as an efficient and convenient approach to suppress nonradiative recombination and improve the photovoltaic performance of hybrid organic-inorganic halide perovskites (HHPs). However, oxygen can seriously undermine the chemical stability of HHPs due to the reaction of superoxide with protonated organic cations such as CH3NH3+ and [(NH2)2CH]+, thus hindering the deep understanding of how oxygen affects their defect properties. Here we substitute free-proton inorganic Cs+ for organic moiety to avoid the negative effect of oxygen and then systematically investigate the oxygen passivation mechanism in all-inorganic halide perovskites (IHPs) from theory to experiment. We find that, in contrast to conventional oxygen molecule passivation just through physisorption on the surface of perovskites, the oxygen atom can provide a better passivation effect due to its stronger interaction with perovskites. The key point to achieve O-passivated perovskites rather than O2 is the dry-air processing condition, which can dissociate the O2 into O during the annealing process. O-passivated IHP solar cells exhibit enhanced power conversion efficiency (PCE) and better air stability than O2-passivated cells. These results not only provide deep insights into the passivation effect of oxygen on perovskites but also demonstrate the great potential of IHPs for high photovoltaic performance with simplified ambient processing.

5.
ACS Appl Mater Interfaces ; 11(27): 24247-24253, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31246410

RESUMO

In-plane anisotropic two-dimensional (2D) materials, especially black phosphorus and ReS2, have attracted significant interest recently as they can provide one more dimension to manipulate their physical properties when compared with isotropic 2D materials. As a representative anisotropic 2D material, germanium monosulfide (GeS) has emerged as a new research hot topic in this field because of its unique in-plane anisotropic physical properties. Despite the rapid growing progress in the study of GeS, many of their fundamental optical anisotropies are still absent. Here, we report the three-dimensional (3D) optical anisotropy of GeS from theory to experiment. The 3D optical anisotropic properties including extinction, refraction, absorption, and reflection were systematically investigated through density functional calculations. The anisotropic refraction and reflection of GeS were experimentally verified by polarization-resolved optical microscopy and azimuth-dependent reflectance difference microscopy, respectively. Finally, a GeS-based linear dichroic photodetector was demonstrated with a dichroic ratio of 1.45 because of its polarization sensitive absorption. Our results provide deep insights into the optical anisotropy of GeS, which is important for the further development of GeS-based optoelectronic and optical devices.

6.
Opt Lett ; 44(7): 1868-1871, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30933168

RESUMO

In advanced biomedicine and microfluidics, there is a strong desire to sort and manipulate various cells and bacteria based on miniaturized microfluidic chips. Here, by integrating fiber tweezers into a T-type microfluidic channel, we report an optofluidic chip to selectively trap Escherichia coli in human blood solution based on different sizes and shapes. Furthermore, we simulate the trapping and pushing regions of other cells and bacteria, including rod-shaped bacteria, sphere-shaped bacteria, and cancer cells based on finite-difference analysis. With the advantages of controllability, low optical power, and compact construction, the strategy may be possibly applied in the fields of optical separation, cell transportation, and water quality analysis.


Assuntos
Separação Celular/instrumentação , Miniaturização/instrumentação , Fibras Ópticas , Pinças Ópticas , Animais , Desenho de Equipamento , Eritrócitos/microbiologia , Escherichia coli/citologia , Humanos
7.
Adv Sci (Weinh) ; 6(5): 1801810, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30886804

RESUMO

Germanium diselenide (GeSe2) has recently emerged as a new member of in-plane anisotropic 2D materials, notable for its wide bandgap of 2.74 eV, excellent air stability, and high performance in polarization-sensitive photodetection. However, the interlayer interaction in GeSe2 has never been reported, which usually plays an important role in layer-number-dependent physical properties. Here, the interlayer coupling in GeSe2 is systematically investigated from theory to experiment. Unexpectedly, all of density functional theory (DFT) calculations about layer-dependent band structures, cleavage energy, binding energy, translation energy, and interlayer differential charge density demonstrate the much weaker interlayer interaction in GeSe2 when compared with black phosphorus (BP). Furthermore, both thickness-dependent and temperature-dependent Raman spectra of GeSe2 flakes, which exhibit no detectable changes of Raman peaks with the increase in thickness and a small first-order temperature coefficient of -0.0095 cm-1 K-1, respectively, experimentally confirm the weakly coupled layers in GeSe2. The results establish GeSe2 as an unusual member of in-plane anisotropic 2D materials with weak interlayer interaction.

8.
J Am Chem Soc ; 140(11): 4150-4156, 2018 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-29494139

RESUMO

In-plane anisotropic layered materials such as black phosphorus (BP) have emerged as an important class of two-dimensional (2D) materials that bring a new dimension to the properties of 2D materials, hence providing a wide range of opportunities for developing conceptually new device applications. However, all of recently reported anisotropic 2D materials are relatively narrow-bandgap semiconductors (<2 eV), and there has been no report about this type of materials with wide bandgap, restricting the relevant applications such as polarization-sensitive photodetection in short wave region. Here we present a new member of the family, germanium diselenide (GeSe2) with a wide bandgap of 2.74 eV, and systematically investigate the in-plane anisotropic structural, vibrational, electrical, and optical properties from theory to experiment. Photodetectors based on GeSe2 exhibit a highly polarization-sensitive photoresponse in short wave region due to the optical absorption anisotropy induced by in-plane anisotropy in crystal structure. Furthermore, exfoliated GeSe2 flakes show an outstanding stability in ambient air which originates from the high activation energy of oxygen chemisorption on GeSe2 (2.12 eV) through our theoretical calculations, about three times higher than that of BP (0.71 eV). Such unique in-plane anisotropy and wide bandgap, together with high air stability, make GeSe2 a promising candidate for future 2D optoelectronic applications in short wave region.

9.
Opt Express ; 26(26): 34665-34674, 2018 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-30650887

RESUMO

Lately, a fiber-based optical tweezer that traps and arranges the micro/nano-particles is crucial in practical applications, because such a device can trap the biological samples and drive them to the designated position in a microfluidic system or vessel without harming them. Here, we report a new type of fiber optical tweezer, which can trap and arrange erythrocytes. It is prepared by coating graphene on the cross section of a microfiber. Our results demonstrate that thermal-gradient-induced natural convection flow and thermophoresis can trap the erythrocytes under low incident power, and the optical scattering force can arrange them precisely under higher incident power. The proposed optical tweezer has high flexibility, easy fabrication, and high integration with lab-on-a-chip, and shows considerable potential for application in various fields, such as biophysics, biochemistry, and life sciences.


Assuntos
Eritrócitos/química , Grafite/química , Dispositivos Lab-On-A-Chip , Nanoestruturas/química , Fibras Ópticas , Pinças Ópticas , Animais , Camundongos
10.
Zhongguo Gu Shang ; 29(2): 154-6, 2016 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-27141786

RESUMO

OBJECTIVE: To investigate the risk factors of pinhole infection in the fractured lower limbs after external fixation. METHODS: The case-control study was designed. From May 2009 to May 2014, the clinical data of 272 patients with lower limb fracture treated by external fixation device were collected. All the patients were divided into two groups according to post-operative pinhole infection. There were 29 cases in the case group including 23 males and 6 females. The age of patients in case group ranged from 25 to 77 years old,with the average age of (53.41 ± 12.77) years old. There were 243 cases in control group including 217 males and 26 females. The age of patients in the control group ranged from 27 to 78 years old, with the average age of (48.71 ± 11.87) years old. There were nine risk factors observed in our study including age, gender, fixed time by external fixation device, diabetes, time in bed, smoking, operation condition of other parts in the body, infection condition of other parts in the body. RESULTS: The results of univariate analysis showed that there were statistically significant differences among age (χ² = 15.708, P < 0.001), fixed time by external fixation device (χ² = 11.940, P < 0.001), severity of the lower limb fracture (χ² =15.438, P < 0.001), diabetes (χ² = 8.519, P = 0.004) and time in bed (χ² = 7.165, P = 0.007) between case group and control group. The results of Logistic regression analysis showed that the risk factors of pinhole infection after fixed by external fixation device in the lower limb fracture were the advanced age (OR = 8.327, P < 0.001), fixed time by external fixation device (OR = 6.795, P < 0.001), diabetes (OR = 4.965, P = 0.001) and time in bed (OR = 4.864, P = 0.008). CONCLUSION: The advanced age, long fixed time, diabetes and long time in bed could increase the risk of pinhole infection after external fixation in the lower limbs with fracture.


Assuntos
Fixadores Externos/efeitos adversos , Extremidade Inferior/lesões , Complicações Pós-Operatórias/etiologia , Adulto , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores de Risco
11.
Zhonghua Zheng Xing Wai Ke Za Zhi ; 29(4): 261-5, 2013 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-24228506

RESUMO

OBJECTIVE: To explore the feasibility and therapeutic effect of thinned posterior tibial artery free perforator flap for the reconstruction of soft tissue defects at dorsum of hands. METHODS: Six fresh adult lower limbs specimens were injected with red latex via arterial cannula and dissected. The number, distribution, branches, and outer diameter of posterior tibia artery perforators were observed. Based on the anatomic study, the perforator flaps were designed to reconstruct soft tissue defects at dorsum of hands and wrists. The redundant fat on the flaps was removed, but preserving the nutrient vascular system. 11 flaps were used with the size ranging from 2 cm x 5 cm to 10 cm x 14 cm. RESULTS: 43 skin perforators of posterior tibial artery were observed in six lower limbs, 29 perforators with the outer diameter is greater than 0.5 mm when they threading over the deep fascia plane, on average every 4.8 bundles of sides. The mean outside diameter of perforating artery is (1.8 +/- 0.5) mm, and the length is (44 +/- 15) mm. 6 perforators were founded both in the second and fifth zone which could be used for anastomosis for its better diameters. All flaps survived completely without any complication at donor sites. 7 cases were followed up for 3-12 months. Both satisfactory functional and cosmetic results were achieved with a soft and thinned appearance. CONCLUSIONS: The thinned posterior tibial artery free perforator flap has a reliable blood supply and good appearance. It is very suitable for the reconstruction of small or medium-sized defects at the dorsum of hands and wrists.


Assuntos
Retalho Perfurante/irrigação sanguínea , Artérias da Tíbia/anatomia & histologia , Artérias da Tíbia/transplante , Adolescente , Adulto , Feminino , Traumatismos da Mão/cirurgia , Humanos , Extremidade Inferior/anatomia & histologia , Extremidade Inferior/irrigação sanguínea , Masculino , Pessoa de Meia-Idade , Procedimentos Cirúrgicos Reconstrutivos/métodos , Adulto Jovem
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