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1.
BMC Vet Res ; 18(1): 8, 2022 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-34980133

RESUMO

BACKGROUND: In animals, weaning stress is the first and most critical stress. Weaning can negatively affect the growth performance of animals physically, psychologically, and pathologically. Our previous studies on the HT-29 cell line and early-weaned rats demonstrated that adequate sophorolipid (SPL) supplementation in feed could enhance the mucin-producing and wound healing capacities of the gut defense system by modulating gut microbiota. METHODS: We conducted an experiment with one hundred forty 21-day-old early weaned piglets (L x Y x D). They were allocated into 4 treatment and 7 replications (4 pigs per pen) according to their initial body weight. Body weight and feed intake were measured biweekly during experimental period. After 6 weeks, 28 pigs were randomly selected and sacrificed to collect plasma, jejunum, and cecal content samples. RESULTS: Dietary SPL supplementation at 5 and 10 mg/kg quadratically increased the average daily gain during the experimental period in the treatment groups when compared with the control group. The albumin levels of piglets fed with the SPL supplemented diet were downregulated to the normal range. Moreover, in feed, SPL supplementation at 5 and 10 mg/kg improved jejunal histological indices and gene expression levels related to mucin secretion and local inflammation markers. Consistent with these results, adequate SPL supplementation (5 and 10 mg/kg) increased the population of Prevotella, a beneficial bacterium, and its short-chain fatty acid production in the ceca of piglets. CONCLUSIONS: The occurrence of diarrhea after weaning in piglets could be reduced by feeding a 10 ppm of SPL supplemented diet which improves the gut defense system by improving the microbial population and enhancing mucin layer integrity.


Assuntos
Ração Animal , Suplementos Nutricionais , Ácidos Oleicos/administração & dosagem , Doenças dos Suínos/prevenção & controle , Ração Animal/análise , Animais , Peso Corporal , Dieta/veterinária , Microbioma Gastrointestinal , Mucinas , Ratos , Suínos , Desmame
2.
Nanotechnology ; 27(39): 395602, 2016 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-27561319

RESUMO

SiOx structures with different diameters of a few hundreds of nanometers and/or a few micrometers are prepared using applied thermal evaporation. Subsequently, Sn quantum dot-based SiOx architectures are synthesized via the continuous steps of the carbothermal reduction of SnO2, substitution of Sn(4+) for In(3+), thermal oxidation of Si, Sn sublimation, interfacial reaction, and diffusion reaction consistent with corresponding phase equilibriums. Several crystalline and spherical-shaped Sn quantum dots with diameters between 2 and 7 nm are observed in the amorphous SiOx structures. The morphological evolution, including hollow Sn (or SnOx) sphere and wire-like, worm-like, tube-like, and flower-like SiOx, occurs stepwise on the Si substrate upon increasing the given process energies. The optical characteristics based on confocal measurements reveal the as-synthesized SiOx structures, irrespective of whether crystallinity is formed, which all have visible-range emissions originating from the numerous different-sized and -shaped Sn quantum dots permeating into the SiOx matrix. In addition, photoluminescence emissions ranging between ultraviolet and red regions are in agreement with confocal measurements. The origins of the morphology- and luminescence-controlled amorphous SiOx with Sn quantum dots are also discussed.

3.
Nanotechnology ; 25(45): 455504, 2014 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-25338675

RESUMO

ZnO hollow fibers (HFs) with a range of wall thicknesses were synthesized by electrospinning and atomic layer deposition. The effects of the wall thickness of the HFs on their sensing properties were examined using CO as a representative reducing gas. The thin-walled HFs showed improved sensor responses to CO compared to thick-walled HFs. Most importantly, despite the polycrystalline nature of HFs, their sensing abilities were determined mainly by the wall thickness, not by the size of the nanograins or crystalline quality. In particular, the resistance modulation was attributed mainly to radial suppression/broadening of the underlying conducting channel during adsorption/desorption of gas species on both the inner and outer surface.

4.
Nanotechnology ; 25(17): 175501, 2014 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-24717769

RESUMO

We have devised a sensor system comprising p-CuO/n-ZnO core-shell nanofibers (CS nanofibers) for the detection of reducing gases with a very low concentration. The CS nanofibers were prepared by a two-step process as follows: (1) synthesis of core CuO nanofibers by electrospinning, and (2) subsequent deposition of uniform ZnO shell layers by atomic layer deposition. We have estimated the sensing capabilities of CS nanofibers with respect to CO gas, revealing that the thickness of the shell layer needs to be optimized to obtain the best sensing properties. It is found that the p-CuO/n-ZnO CS structures are suitable for detecting reducing gases at extremely low concentrations. The associated sensing mechanism is proposed on the basis of the radial modulation of an electron-depleted region in the shell layer.

5.
Psychiatry Investig ; 21(3): 230-241, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38569581

RESUMO

OBJECTIVE: This study evaluated the clinical effectiveness of Minds.NAVI, a depression screening kit combining psychometric measures and stress hormone biomarkers, in a prospective clinical trial. The objective was to assess its potential as a depression screening tool and investigate the associations between psychological assessments, salivary hormone staging, and depression severity. METHODS: Thirty-five participants with major depressive disorder and 12 healthy controls (HCs) were included. The Minds.NAVI software, utilizing the PROtective and Vulnerable factors battEry Test (PROVE) and salivary cortisol/dehydroepiandrosterone (DHEA) analysis, was employed. The PROVE test is a comprehensive self-report questionnaire that assesses depressive symptoms, suicide risk, attachment style, adverse childhood experiences, mentalization capacity, and resilience. In addition, salivary cortisol and DHEA levels were measured to evaluate the functional stage of the hypothalamic-pituitary-adrenal (HPA) axis. RESULTS: Minds.NAVI exhibited 100% sensitivity, 91.7% specificity, and 97.9% accuracy in distinguishing depression from HCs within an exploratory small group. Salivary stress hormone phases showed changes with depression stage (p=0.030), and the proportion of patients with "adrenal exhaustion stage" was higher in the moderate/severe depression group (p=0.038). Protective/vulnerable factors differed significantly between controls and depressed groups (p<0.001). Cortisol awakening response inversely correlated with depressive symptom severity (r=-0.31, p=0.034). CONCLUSION: This study suggested possible clinical effectiveness of Minds.NAVI, a depression screening tool that integrates psychometric measures and stress hormone biomarkers. The findings support the potential association between depression, chronic stress, and HPA axis hyporesponsiveness.

6.
Nanotechnology ; 24(2): 025504, 2013 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-23237979

RESUMO

Networked SnO(2) nanowire sensors were achieved using the selective growth of SnO(2) nanowires and their tangling ability, particularly on on-chip V-groove structures, in an effort to overcome the disadvantages imposed on the conventional trench-structured SnO(2) nanowire sensors. The sensing performance of the V-groove-structured SnO(2) nanowire sensors was highly dependent on the geometrical dimension of the groove, being superior to those of their conventional trench-structured counterparts. Pt nanoparticles were decorated on the surface of the networked SnO(2) nanowires via γ-ray radiolysis to enhance the sensing performances of the V-groove sensors whose V-groove widths had been optimized. The V-groove-structured Pt-nanoparticle-decorated SnO(2) nanowire sensors exhibited outstanding and reliable sensing capabilities towards toluene and nitrogen dioxide gases, indicating their potential for use as a platform for chemical gas sensors.


Assuntos
Condutometria/instrumentação , Cristalização/métodos , Gases/análise , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Platina/química , Compostos de Estanho/química , Condutividade Elétrica , Desenho de Equipamento , Análise de Falha de Equipamento , Tamanho da Partícula
7.
J Nanosci Nanotechnol ; 13(10): 7097-9, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24245200

RESUMO

Room temperature gas sensing ability for low concentrations of benzene was successfully realized with Pt nanoparticle-decorated networked ZnO nanowire sensors. For decoration of Pt nanoparticles, gamma-ray radiolysis was used. The Pt decoration greatly enhanced benzene sensing performances. Importantly, even at room temperature, ppm level benzene was clearly detected, which is likely to be due to the combined effect of electronic and chemical sensitizations by Pt nanoparticles.

8.
Front Psychiatry ; 14: 1293347, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38268560

RESUMO

Introduction: Borderline personality disorder (BPD) is characterized by interpersonal and emotional instabilities, recurring suicidal tendencies, and feelings of emptiness. Childhood adverse event is reported in 70%-80% of cases involving BPD. Furthermore, the deficiency in mentalization capacity plays a significant role in emotion dysregulation and social interaction problems within individuals with BPD. This study explored the relationship among childhood adverse experiences, mentalization capacity, and neurophysiological activity in patients with BPD. Methods: Resting-state electroencephalography was used to identify the neural correlates associated with childhood adversity and mentalization deficits. The participants included 45 patients with BPD and 15 healthy controls. Results: The BPD group exhibited reduced alpha activity during eyes-closed rest, indicating heightened arousal even during relaxation. Correlations were found between the power spectral density (PSD) and mentalization capacity in the delta and theta ranges, suggesting an association between PSD and emotional awareness and expression. Gamma activity negatively correlated with psychic equivalence, implying a blurring of the boundaries between internal mental experiences and the external world. Conclusion: These findings offer insights into the pathophysiology of BPD, provide potential diagnostic markers, and suggest personalized treatment approaches based on mentalization traits.

9.
J Nanosci Nanotechnol ; 12(2): 1288-91, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22629940

RESUMO

NiO nanofibers were synthesized by an electrospinning method with polyvinyl alcohol and nickel acetate tetrahydrate as precursor materials. Individual nanofibers consisted of nanograins. A gas sensor has been fabricated using these nanofibers. Its sensing properties to NO2 and benzene were investigated. The sensor exhibited good sensitivity and dynamic properties for the tested gases. All these results suggest that the electrospinning-synthesized NiO nanofibers hold promise for realizing sensitive and reliable gas sensors.

10.
J Nanosci Nanotechnol ; 12(2): 1526-9, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22629993

RESUMO

Selectively-grown networked SnO2 nanowires were functionalized with Pt nanodots by the radiolysis process. NO2 sensing characteristics of Pt-functionalized SnO2 nanowires were compared with those of bare SnO2 nanowires. The results demonstrate that the Pt functionalization greatly enhances the sensitivity and response time in SnO2 nanowire-based gas sensors. The enhancement is likely to be associated with the spillover effect and/or easy dissociation of NO2 into more active chemical species by the catalytic effect of Pt.

11.
Front Psychiatry ; 13: 847498, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35711598

RESUMO

Objectives: Adverse childhood experiences (ACEs) are fundamental factors in developing depression with increased suicide risk. Resilience is considered an important protective factor that can prevent trauma survivors from developing depression. We developed a home evaluation kit for a comprehensive assessment of bio-psycho-social factors related to depression and suicide. This kit contained a psycho-social evaluation battery, named the Protective and Vulnerable factors battery questionnaire (PROVE) comprising depressive symptoms and suicide risk, as well as various depression-related psychosocial factors, such as ACE, resilience, mentalization capacity, and attachment, via online survey tools. Furthermore, salivary cortisol levels were used as biological indicators to assess the hypothalamus-pituitary-adrenal axis function. Methods: Real-world data analysis was made out of data collected from participants who visited CHEEU Counseling center or Gangnam Severance hospital for mental health check-ups. The participants were put into three mental state groups (green-normal, yellow-borderline, and red-risk) depending on the result of PROVE battery. The difference between psychosocial factors and salivary cortisol indicators by the group was identified by analysis of covariance with sex and age as covariates. Linear regression analysis was conducted to find a significant association of resilience score with other bio-psycho-social variables, such as ACE, attachment, mentalization, or post-awakening cortisol concentrations (area under the curve with respect to ground, AUCg). A partial correlation analysis was performed to evaluate the relationship of AUCg with psychosocial factors. Results: Depression-related psycho-social indicators were significantly different among groups. Insecure attachment and the mentalization problem are negatively influencing factors to resilience. Furthermore, the severity of depression in participants with ACE was also influenced by mentalization problems. AUCg was different according to the PROVE group, presence of ACE, or resilience level. In addition, AUCg showed a positive correlation with resilience score but negative correlations with depressive symptoms, ACE, mentalization problems, and anxiety or avoidance attachment. Conclusion: This study suggests that there are some key factors negatively affecting resilience: insecure attachment and mentalization problems. In groups with ACE, a mentalization problem was suggested as a factor that can increase depressive symptoms. AUCg was associated with resilience as well as several other vulnerable factors of depression, showing its potential as a promising biomarker.

12.
Animals (Basel) ; 12(5)2022 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-35268204

RESUMO

Dietary fat and oil could aid in reaching the high-energy requirements of fast-growing birds; however, these inclusions could lead to nutrient waste. This is because young birds have limited lipid digestion due to the low secretion of lipase and bile salt. Sophorolipid (SPL), a glycolipid emulsifier with lower toxicity and higher biodegradability, can upregulate fat utilization by increasing digestibility. Accordingly, a five-week-long experiment was conducted with 720 one-day-old chicks (Ross 308) to investigate the effects of dietary SPL on growth, organ characteristics, and gut health. The allotment was partitioned into four treatment groups according to their body weight with six replications (30 chick/pen). The three treatment diets comprised a basal diet with a formulation that met the Ross 308 standard and 5, 10, and 15 ppm SPL in the basal diet. During the experiment, the birds had free access to feed, and body weight and feed intake were measured at the end of each phase. Chickens were put down at the end of the growing and finishing phases, and jejunum and cecal samples were obtained to investigate organ characteristics and gut environments. The data were analyzed using the generalized linear model procedures of SAS 9.4, and all data were assessed for linear, quadratic, and cubic effects of dietary SPL-supplemented dosages. Body weight was significantly increased with 10 ppm of SPL supplementation in the grower phase without affecting feed efficiency. The relative weights of the intestine and the bursa of Fabricius were quadratically decreased by SPL supplementation with a lower population of Streptococcus and higher propionate and butyrate concentrations. Additionally, the dietary SPL supplementation groups showed a significantly increased villus/crypt ratio with higher intestinal expression levels of fatty acid translocase, diacylglycerol acyltransferase 2, and fatty acid transporter 4. Collectively, proper SPL supplementation in the chicken diet could improve growth performance by down-regulating immune modulation and up-regulating lipid digestion and absorption via modulation of gut microenvironments.

13.
J Hazard Mater ; 432: 128671, 2022 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-35303661

RESUMO

In humid conditions, water vapor can easily neutralize the surface active sites of metal oxide sensors, leading to a lowering in the sensitivity of the gas sensor and a resultant inaccurate signal in practical applications. Herein, we present a new hybrid sensor by introducing a two-dimensional calcium silicate (CS) nanosheet as a water-trapping layer in SnO2 nanowires. Unlike the heavily wrinkled and aggregated morphology of conventional CS nanosheets, our nanosheet in the hybrid material is ultrathin and flat. Moreover, it was grown in the empty spaces between the spider-web-like networks of SnO2 nanowires without covering the nanowire surface. These two morphological features improve moisture trapping with minimal reduction in the active sensing area. Consequently, stable and sensitive gas detection under humid conditions was achieved in this hybrid sensor. The superior humidity-independent sensing is ascribed to the preferential adsorption of water molecules on hydroscopic CS nanosheets through the hydrogen bond. Based on density functional theory calculations, we determined that the improved gas response is driven by the additional formation of oxygen vacancy in SnO2 due to the diffusion of aliovalent Ca ions from the CS nanosheet.

14.
Front Psychiatry ; 13: 1057513, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36741575

RESUMO

Objectives: As the significance of the early diagnosis of mild cognitive impairment (MCI) has emerged, it is necessary to develop corresponding screening tools with high ecological validity and feasible biomarkers. Virtual reality (VR)-based cognitive assessment program, which is close to the daily life of the older adults, can be suitable screening tools for MCI with ecological validity and accessibility. Meanwhile, dehydroepiandrosterone (DHEA) has been observed at a low concentration in the older adults with dementia or cognitive decline, indicating its potential as a biomarker of MCI. This study aimed to determine the efficacy and usability of a VR cognitive assessment program and salivary DHEA for screening MCI. Methods: The VR cognitive assessment program and the traditional Montreal Cognitive Assessment (MOCA) test were performed on 12 patients with MCI and 108 healthy older adults. The VR program operates in a situation of caring for a grandchild, and evaluates the memory, attention, visuospatial, and executive functions. An analysis of covariance (ANCOVA), a partial correlation analysis, and receiving operating characteristic (ROC) curve analysis were conducted for statistical analysis. Results: According to the ANCOVA, no significant difference in MOCA scores was found between the normal and MCI groups (F = 2.36, p = 0.127). However, the VR total score of the MCI group was significantly lower than that of the normal group (F = 8.674, p = 0.004). There was a significant correlation between the MOCA and VR scores in the total and matched subdomain scores. The ROC curve analysis also showed a larger area under the curve (AUC) for the VR test (0.765) than for the MOCA test (0.598), and the sensitivity and specificity of the VR program were 0.833 and 0.722, respectively. Salivary DHEA was correlated with VR total (R 2 = 0.082, p = 0.01) and attention scores (R 2 = 0.086, p = 0.009). Conclusion: The VR cognitive test was as effective as the traditional MOCA test in the MCI classification and safe enough for older adults to perform, indicating its potential as a diagnostic tool. It has also been shown that salivary DHEA can be used as a biomarker for MCI.

15.
Nanotechnology ; 22(22): 225501, 2011 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-21454939

RESUMO

γ-ray radiolysis is applied to synthesizing Pd nanodots on networked SnO(2) nanowires. The growth behavior of Pd nanodots is systematically investigated as a function of the precursor concentration, illumination intensity, and exposure time of the γ-rays. These factors greatly influence the growth behavior of the Pd nanodots. Selectively grown networked SnO(2) nanowires are uniformly functionalized with Pd nanodots by the radiolysis process. The NO(2) sensing characteristics of the Pd-functionalized SnO(2) nanowires are compared with those of bare SnO(2) nanowires. The results indicate that γ-ray radiolysis is an attractive means of functionalizing the surface of oxide nanowires with catalytic Pd nanodots. Moreover, the Pd-functionalization greatly enhances the sensitivity and response time in SnO(2) nanowire-based gas sensors.

16.
Pain Physician ; 24(4): E467-E475, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34213872

RESUMO

BACKGROUND: Although many studies have compared full endoscopic spine surgery and open spine surgery, few have compared the outcomes of percutaneous endoscopic interlaminar lumbar discectomy (PEILD) and open lumbar microdiscectomy (OLM) at the L5-S1 level. OBJECTIVES: We compared the clinical, surgical, and radiological outcomes of patients with disc herniation at the L5-S1 level who underwent either PEILD, or OLM, performed by a single surgeon with novice-level proficiency. STUDY DESIGN: Observational, retrospective matched cohort design. SETTING: An analysis of clinical data was performed at a single center, collected from September 2012 to August 2016. METHODS: The study enrolled 56 patients who underwent discectomy at the L5-S1 level, with a minimum one-year follow-up. Patients were allocated to 2 groups: a PEILD group (n = 27; September 2014 to August 2016), or an OLM group (n = 29; September 2012 to August 2014). Clinical, surgical, and radiological outcomes were retrospectively evaluated. RESULTS: Baseline characteristics including age, gender, past medical history, body mass index, preoperative symptom, and preoperative radiological findings did not differ significantly between the groups. Further, overall clinical outcomes including back and leg pain; surgical outcomes including blood loss, complication rate, and recurrence rate; and radiological outcomes including degree of decompression, disc height, and sagittal alignment were not different significantly between the 2 groups.However, the PEILD group showed significant advantages including lower immediate postoperative back pain (mean 1.44 [95% confidence interval (CI), 1.16-1.72] versus 2.41 [95% CI, 2.14-2.69], P < 0.001), favorable immediate postoperative Odom's criteria (excellent 57.14% versus 24.14%, P = 0.025), shorter operation time (mean 63.89 ±17.99 minutes versus 109.66 ±31.42 minutes, P < 0.001), shorter hospital stay (3.15 [95% CI, 2.21-4.09] days versus 5.72 [95% CI, 3.29-8.16] days, P < 0.001), and rapid return to work (15.67 [95% CI, 12.64-18.69] days versus 24.31 [95% CI ,19.97-28.65] days, P = 0.001). LIMITATION: Due to its retrospective nature, it was not possible to control for all variations. Moreover, the number of patients in the final cohort was relatively small. CONCLUSIONS: Our findings indicate that the PEILD group achieved better perioperative outcomes despite no significant intergroup difference in mid-term clinical and radiological outcomes.


Assuntos
Discotomia Percutânea , Deslocamento do Disco Intervertebral , Discotomia , Endoscopia , Humanos , Deslocamento do Disco Intervertebral/diagnóstico por imagem , Deslocamento do Disco Intervertebral/cirurgia , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/cirurgia , Estudos Retrospectivos , Resultado do Tratamento
17.
Clin Psychopharmacol Neurosci ; 19(1): 73-83, 2021 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-33508790

RESUMO

OBJECTIVE: Repetitive transcranial magnetic stimulation (rTMS) has contributed to increase in the remission rate for patients with major depressive disorder (MDD). However, current rTMS treatment is practically inconvenient because it requires daily treatment sessions for several weeks. Accelerated rTMS treatment is as efficient and safe for MDD patients as conventional rTMS. METHODS: Fifty-one patients with MDD participated in this study; they were randomized into accelerated rTMS (n = 21), conventional rTMS (n = 22), and sham-treatment (n = 8) groups. The accelerated and conventional rTMS groups received 15 sessions for 3 days and 3 weeks, respectively. The sham-treatment group received 15 sham rTMS sessions for 3 days. Primary outcome was assessed using self-report and clinician-rated Korean Quick Inventory of Depressive Symptomatology (KQIDS-SR and KQIDS-C, respectively). Adverse effects were monitored using the Frequency, Intensity, and Burden of Side Effects Rating scale. Changes in depressive symptoms were compared among the three groups using mixed model analyses. RESULTS: For the KQIDS-SR score, there was a significant main effect of "time" (F3,47 = 11.05, p < 0.001), but no effect of "group" (F2,47 = 2.04, p = 0.142), and a trend-level interaction effect of "group × time" (F6,47 = 2.26, p = 0.053). Improvement in depressive symptoms, based on the KQIDS-SR score 3 weeks after treatment, was more prominent in the accelerated rTMS group than in the sham-treatment group (p = 0.011). Tolerability was comparable among the three groups. CONCLUSION: The accelerated rTMS treatment group showed rapid improvement of depressive symptoms compared with the sham-treatment and conventional rTMS treatment groups. Therefore, accelerated rTMS treatment could be a viable option for MDD, with improved accessibility.

18.
Nanotechnology ; 21(47): 475601, 2010 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-21030772

RESUMO

A novel approach is applied to fabricating hollow ZnO nanofibers (ZNFs) with uniform wall thicknesses. In this approach, polymers synthesized by electrospinning are used as sacrificial templates and ZnO is subsequently deposited on these templates using atomic layer deposition, which makes ZnO uniformly cover the round surface of the polymer nanofibers. Heat treatments result in the selective removal of the polymer templates and the formation of hollow ZNFs with very uniform wall thicknesses. To test a potential use of hollow ZNFs in chemical gas sensors, their sensing properties with regard to O(2), NO(2), and CO are investigated in a comparative manner with those of normal ZnO nanofibers. The excellent sensing properties observed in the hollow ZNF sensor are ascribed to (1) the more pronounced change in resistance due to the presence of nanograins and (2) the doubling of the surface-to-volume ratio due to the generation of inner surfaces.

19.
Nanotechnology ; 21(41): 415502, 2010 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-20852351

RESUMO

We report a significant enhancement in the gas sensing properties of In(2)O(3) nanowires by functionalizing their surfaces with Pt nanoparticles. For Pt-functionalization, In(2)O(3)-Pt core-shell nanowires are synthesized by the sputtering deposition of Pt layers on bare In(2)O(3) nanowires. Next, continuous Pt shell layers are transformed into Pt nanoparticles of cubic phase by heat treatment. In an O(2) gas sensing test, the Pt-functionalized In(2)O(3) nanowires reveal exceptionally higher sensitivity and faster response than bare In(2)O(3) nanowires.

20.
J Nanosci Nanotechnol ; 10(5): 3604-8, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20359009

RESUMO

Present study focuses the effect of calcination temperature and its duration on the morphology and growth of nanograins in individual TiO2 nanofibers synthesized by electrospinning method. Polyvinyl acetate and titanium tetraisopropoxide were used as chemical precursors along with other standard solvents in the synthesis process. This study shows that synthesized TiO2 nanofibers are randomly arranged and spreads uniformly over the Si substrate and possess polycrystalline nature consisting of nanograins. Similar to the sintering behavior generally observed in bulk ceramics, the nanograins coalesce and grow under higher calcination temperature and longer calcination time. The activation energy for the growth of nanograins is found to be 47.2 kJ/mol. The dominant growth mechanism changes depending on the stages of calcination.

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