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1.
Am J Vet Res ; : 1-5, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38942062

RESUMO

OBJECTIVE: To improve the current recommendations for the diagnosis of canine heartworm (Dirofilaria immitis) disease. ANIMALS: Blood samples collected from 35 shelter dogs in the Republic of Korea. METHODS: Samples were tested for the presence of microfilaria using the modified Knott (MK) test and D immitis DNA using species-specific loop-mediated isothermal amplification (LAMP) PCR. The blood samples were additionally assessed for the presence of heartworm antigens using the Antigen Rapid Canine Heartworm AG Test Kit 2.0 (Bionote Co). The performance of the MK test and LAMP PCR was assessed through statistical analysis, with a paired McNemar test utilized for comparison. RESULTS: The heartworm antigen was detected in 28.5% of the subjects. Of the 10 positive animals, the MK test detected microfilaria in 4 of 35 (11.4%) animals, and LAMP PCR detected D immitis DNA in 6 of 35 (17.1%). The results of this study indicate that the LAMP PCR showed more positive results in samples compared to the conventional MK test. CLINICAL RELEVANCE: The D immitis-specific LAMP PCR assay has the potential to function as an alternative to current detection methods. It could complement the existing antigen detection tests in diagnosing canine heartworm infections.

2.
Emerg Infect Dis ; 30(5): 908-915, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38666567

RESUMO

Considering patient room shortages and prevalence of other communicable diseases, reassessing the isolation of patients with Clostridioides difficile infection (CDI) is imperative. We conducted a retrospective study to investigate the secondary CDI transmission rate in a hospital in South Korea, where patients with CDI were not isolated. Using data from a real-time locating system and electronic medical records, we investigated patients who had both direct and indirect contact with CDI index patients. The primary outcome was secondary CDI transmission, identified by whole-genome sequencing. Among 909 direct and 2,711 indirect contact cases, 2 instances of secondary transmission were observed (2 [0.05%] of 3,620 cases), 1 transmission via direct contact and 1 via environmental sources. A low level of direct contact (113 minutes) was required for secondary CDI transmission. Our findings support the adoption of exhaustive standard preventive measures, including environmental decontamination, rather than contact isolation of CDI patients in nonoutbreak settings.


Assuntos
Clostridioides difficile , Infecções por Clostridium , Humanos , Infecções por Clostridium/transmissão , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/microbiologia , Clostridioides difficile/genética , Clostridioides difficile/isolamento & purificação , República da Coreia/epidemiologia , Estudos Retrospectivos , Feminino , Masculino , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/transmissão , Infecção Hospitalar/microbiologia , Fatores de Tempo , Idoso , Pessoa de Meia-Idade , Adulto , Busca de Comunicante
3.
J Korean Soc Radiol ; 85(1): 204-209, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38362394

RESUMO

Mediastinal vascular malformations are rare and their diagnosis can be challenging. Imaging is vital for diagnosing mediastinal vascular malformations and can help avoid unnecessary invasive procedures. Herein, we report the detailed CT and MRI findings of a rare low-flow mediastinal vascular malformation in an asymptomatic 63-year-old male.

4.
Open Vet J ; 13(9): 1124-1134, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37842100

RESUMO

Background: Canine lymphoma is one of the most commonly reported hematopoietic tumors. Aim: A few retrospective studies have involved complex evaluations including diagnostic features and treatment protocols, but these studies infrequently demonstrate variable factors that affect survival time, and comparisons among chemotherapeutic protocols are limited. This study aimed to identify prognostic factors that can be simply detected in dogs with lymphoma, such as abnormalities in physical and hematologic findings, and treatment protocols. Methods: Clinical records of 77 dogs diagnosed with lymphoma were retrospectively reviewed. Results: The author newly identified leukocyte and platelet abnormalities as negative prognostic factors. Furthermore, this study suggests that decreased gastrointestinal toxicity and improvements of hematologic abnormalities, such as anemia, thrombocytopenia, and lymphocytosis or lymphoblasts, in peripheral blood during chemotherapy act as positive prognostic factors. Finally, strict adherence to therapeutic protocol and selecting multiple agents as rescue protocol are important to prolong survival time. Conclusion: This study identified indicators to be used as prognostic factors through survival analysis.


Assuntos
Doenças do Cão , Linfoma , Trombocitopenia , Cães , Animais , Estudos Retrospectivos , Linfoma/diagnóstico , Linfoma/veterinária , Linfoma/tratamento farmacológico , Trombocitopenia/tratamento farmacológico , Trombocitopenia/veterinária , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Análise de Sobrevida , Doenças do Cão/tratamento farmacológico
5.
Proc ACM SIGCHI ; 2023: 484-495, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38751573

RESUMO

Social support plays a crucial role in managing and enhancing one's mental health and well-being. In order to explore the role of a robot's companion-like behavior on its therapeutic interventions, we conducted an eight-week-long deployment study with seventy participants to compare the impact of (1) a control robot with only assistant-like skills, (2) a coach-like robot with additional instructive positive psychology interventions, and (3) a companion-like robot that delivered the same interventions in a peer-like and supportive manner. The companion-like robot was shown to be the most effective in building a positive therapeutic alliance with people, enhancing participants' well-being and readiness for change. Our work offers valuable insights into how companion AI agents could further enhance the efficacy of the mental health interventions by strengthening their therapeutic alliance with people for long-term mental health support.

6.
User Model User-adapt Interact ; 33(2): 571-615, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38737788

RESUMO

Despite the increase in awareness and support for mental health, college students' mental health is reported to decline every year in many countries. Several interactive technologies for mental health have been proposed and are aiming to make therapeutic service more accessible, but most of them only provide one-way passive contents for their users, such as psycho-education, health monitoring, and clinical assessment. We present a robotic coach that not only delivers interactive positive psychology interventions but also provides other useful skills to build rapport with college students. Results from our on-campus housing deployment feasibility study showed that the robotic intervention showed significant association with increases in students' psychological well-being, mood, and motivation to change. We further found that students' personality traits were associated with the intervention outcomes as well as their working alliance with the robot and their satisfaction with the interventions. Also, students' working alliance with the robot was shown to be associated with their pre-to-post change in motivation for better well-being. Analyses on students' behavioral cues showed that several verbal and nonverbal behaviors were associated with the change in self-reported intervention outcomes. The qualitative analyses on the post-study interview suggest that the robotic coach's companionship made a positive impression on students, but also revealed areas for improvement in the design of the robotic coach. Results from our feasibility study give insight into how learning users' traits and recognizing behavioral cues can help an AI agent provide personalized intervention experiences for better mental health outcomes.

7.
Taehan Yongsang Uihakhoe Chi ; 83(2): 387-393, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36237923

RESUMO

Primary pulmonary malignant melanoma is an extremely rare type of melanoma. The radiologic features of primary pulmonary malignant melanoma are nonspecific; however, it almost always presents as a well-demarcated round or lobulated solitary solid nodule or mass. Herein, we report the case of a 78-year-old male with primary pulmonary malignant melanoma that was mistaken for primary pulmonary adenocarcinoma with lepidic growth and was seen as bilateral multiple subsolid nodules on CT.

9.
Korean J Radiol ; 21(8): 1018-1023, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32677386

RESUMO

The coronavirus disease (COVID-19) outbreak has reached global pandemic status as announced by the World Health Organization, which currently recommends reverse transcription polymerase chain reaction (RT-PCR) as the standard diagnostic tool. However, although the RT-PCR test results may be found negative, there are cases that are found positive for COVID-19 pneumonia on computed tomography (CT) scan. CT is also useful in assessing the severity of COVID-19 pneumonia. When clinicians desire a CT scan of a patient with COVID-19 to monitor treatment response, a safe method for patient transport is necessary. To address the engagement of medical resources necessary to transport a patient with COVID-19, our institution has implemented the use of mobile CT. Therefore, we report two cases of COVID-19 pneumonia evaluated by using mobile cone-beam CT. Although mobile cone-beam CT had some limitations regarding its image quality such as scatter noise, motion and streak artifacts, and limited field of view compared with conventional multi-detector CT, both cases had acceptable image quality to establish the diagnosis of COVID-19 pneumonia. We report the usefulness of mobile cone-beam CT in patients with COVID-19 pneumonia.


Assuntos
Betacoronavirus , Infecções por Coronavirus/diagnóstico por imagem , Tomografia Computadorizada Multidetectores/instrumentação , Pneumonia Viral/diagnóstico por imagem , Idoso , COVID-19 , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pandemias , SARS-CoV-2
10.
Skeletal Radiol ; 49(10): 1589-1595, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32382979

RESUMO

OBJECTIVE: To assess the diagnostic performance of dual-energy computed tomography (DECT) with the color-coded virtual non-calcium (VNC) technique for detecting acute fractures in patients after acute spine trauma, especially in an emergency clinical setting. MATERIALS AND METHODS: Our retrospective study included 31 patients presented to emergency department with suspected spine trauma. All patients underwent both DECT (80 kVp and 140 kVp) and MRI. Post-processing was performed using color-coded VNC technique. Two independent radiologists visually assessed color-coded VNC images in a random order, and one of the two readers re-assessed the images in 4 weeks after the initial assessment. They were allowed to read only color-coded VNC images and asked to determine the presence of acute fracture. To determine the standard reference point, the other two experienced radiologists made consensus readings on both grayscale CT and MRI. Sensitivity, specificity, PPV, NPV, and accuracy analyses were determined. Both intra- and inter-observer agreements were also calculated. RESULTS: A total of 217 vertebral bodies (65 thoracic and 152 lumbar vertebrae) were included in our study. Sensitivity was 83.3% and 76.7% for first and second readers, respectively. Specificity of 99.5% and 98.9%, PPV of 96.1% and 96.3%, NPV of 97.3% and 96.3%, and accuracy of 97.2% and 95.8%, respectively, were noted. Both intra-observer and inter-observer agreements indicated excellent agreement (κ = 0.86 and κ = 0.84, respectively). CONCLUSION: In spite of the relatively low sensitivity, DECT-based detection of acute spinal fractures showed good specificity, positive predictive value, negative predictive value, accuracy, and inter-/intra-observer agreements.


Assuntos
Fraturas da Coluna Vertebral , Medula Óssea , Edema , Humanos , Reprodutibilidade dos Testes , Estudos Retrospectivos , Sensibilidade e Especificidade , Fraturas da Coluna Vertebral/diagnóstico por imagem , Tomografia Computadorizada por Raios X
11.
ACS Appl Mater Interfaces ; 12(1): 1322-1329, 2020 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-31840977

RESUMO

Compared with traditional metal-oxide lithium-ion battery (LIB) cathodes, nanocarbon-based cathode materials have received much attention for potential application in LIBs because of their superior power density and long-term cyclability. However, their lithium-ion storage capacity needs further improvement for practical applications, and the trade-off between capacity and conductivity, when oxygen functional groups as lithium-ion storage sites are introduced to the nanocarbon materials, needs to be addressed. Here, we report a sequential oxidation-reduction process for the synthesis of single-walled carbon nanotubes (SWCNTs) for LIB cathodes with fast charging, long-term cyclability, and high gravimetric capacity. A LIB cathode based on highly exfoliated (dbundle < 10 nm) and oxygen-functionalized single-walled carbon nanotubes is obtained via the modified Brodie's method using fuming nitric acid and a mild oxidant (B-SWCNTs). Post treatment including horn sonication and hydrogen thermal reduction developed surface defects and removed the unnecessary C-O groups, resulting in an increase in the Li-ion storage capacity. The B-SWCNTs exhibit a high reversible gravimetric capacity of 344 mA h g-1 at 0.1 A g-1 without noticeable capacity fading after 1000 cycles. Furthermore, it delivers a high gravimetric energy density of 797 W h kgelectrode-1 at a low gravimetric power density of 300 W kgelectrode-1 and retains its high gravimetric energy density of ∼100 W h kgelectrode-1 at a high gravimetric power of 105 W kgelectrode-1. These results suggest that the highly exfoliated, oxygen-functionalized single-walled carbon nanotubes can be applied to LIBs designed for high-rate operations and long cycling.

12.
Pediatrics ; 144(1)2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31243158

RESUMO

BACKGROUND AND OBJECTIVES: Social robots (SRs) are increasingly present in medical and educational contexts, but their use in inpatient pediatric settings has not been demonstrated in studies. In this study, we aimed to (1) describe the introduction of SR technology into the pediatric inpatient setting through an innovative partnership among a pediatric teaching hospital, robotics development, and computational behavioral science laboratories and (2) present feasibility and acceptability data. METHODS: Fifty-four children ages 3 to 10 years were randomly exposed to 1 of 3 interventions: (1) interactive SR teddy bear; (2) tablet-based avatar version of the bear; or (3) plush teddy bear with human presence. We monitored intervention enrollment and completion patterns, obtained qualitative feedback on acceptability of SR use from child life-specialist stakeholders, and assessed children's positive and negative affect, anxiety, and pain intensity pre- and postintervention. RESULTS: The intervention was well received and appeared feasible, with 93% of those enrolled completing the study (with 80% complete parent data). Children exposed to the SR reported more positive affect relative to those who received a plush animal. SR interactions were characterized by greater levels of joyfulness and agreeableness than comparison interventions. Child life specialist stakeholders reported numerous potential benefits of SR technology in the pediatric setting. CONCLUSIONS: The SR appears to be an engaging tool that may provide new ways to address the emotional needs of hospitalized children, potentially increasing access to emotionally targeted interventions. Rigorous development and validation of SR technology in pediatrics could ultimately lead to scalable and cost-effective tools to improve the patient care experience.


Assuntos
Ansiedade/prevenção & controle , Criança Hospitalizada/psicologia , Dor/prevenção & controle , Jogos e Brinquedos , Robótica , Criança , Pré-Escolar , Computadores de Mão , Estudos de Viabilidade , Humanos , Prazer
13.
Food Microbiol ; 82: 171-176, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31027771

RESUMO

We examined the control effect of a 222-nm KrCl excilamp on foodborne pathogens on alfalfa seeds and compared it with a conventional 254-nm low-pressure (LP) Hg lamp. When the 222-nm KrCl excilamp treated seeds at 87, 174 and 261 mJ/cm2, the log reductions of Escherichia coli O157:H7 (E. coli O157:H7) were 0.85, 1.77, and 2.77, respectively, and Salmonella Typhimurium (S. Typhimurium) experienced log reductions of 1.22, 2.27, and 3.04, respectively. When the 254-nm LP Hg lamp was applied at 87, 174, and 261 mJ/cm2, the log reductions of E. coli O157: H7 were 0.7, 1.16, and 1.43, respectively, and those of S. Typhimurium were 0.75, 1.15, and 1.85, respectively. Therefore, it was shown that the 222-nm KrCl excilamp was more effective than the 254-nm LP Hg lamp in reducing foodborne pathogens. The germination rate decreased to less than 80% after 261 mJ/cm2 treatment with the 254-nm LP Hg lamp, while more than 90% was maintained with 261 mJ/cm2 222-nm KrCl excilamp treatment. DNA damage assay showed that the difference in germination rate was due to DNA damage resulting from 254-nm LP Hg lamp treatment. However, 222 nm KrCl excilamp treatment did not cause DNA damage, resulting in no difference in germination rate compared to that of non-treated alfalfa seeds. Overall, these results demonstrate the utility of the 222-nm KrCl excilamp as a foodborne pathogen control intervention for the alfalfa seed industry.


Assuntos
Escherichia coli O157/efeitos da radiação , Irradiação de Alimentos/normas , Microbiologia de Alimentos/métodos , Germinação/efeitos da radiação , Medicago sativa , Salmonella typhimurium/efeitos da radiação , Sementes/microbiologia , Cloretos/química , Contagem de Colônia Microbiana , Criptônio/química , Lasers de Excimer , Sementes/fisiologia
14.
Nutrients ; 10(3)2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29494494

RESUMO

Inflammatory bowel disease (IBD), encompassing ulcerative colitis and Crohn's disease, is a multifactorial inflammatory disease of the small intestine and colon. Many investigators have reported that l-glutamine (Gln) therapy improves outcomes of experimental colitis models, although the mechanism is not fully understood. Regarding the anti-inflammatory properties of Gln, we have shown that Gln can effectively deactivate cytosolic phospholipase A2 (cPLA2) by rapid induction of MAPK phosphatase (MKP)-1. In this study, we explore the possibility that Gln ameliorates dextran sulfate sodium (DSS)-induced colitis via MKP-1 induction, resulting in inhibition of cPLA2, which has been reported to play a key role in the pathogenesis of IBD. Oral Gln intake attenuated DSS-induced colitis. Gln inhibited cPLA2 phosphorylation, as well as colonic levels of TNF-α and leukotriene (LT)B4. Gln administration resulted in early and enhanced MKP-1 induction. Importantly, MKP-1 small interfering RNA (siRNA), but not control siRNA, significantly abrogated the Gln-mediated (1) induction of MKP-1; (2) attenuation of colitis (colon length, histological abnormality, and inflammation; and (3) inhibition of cPLA2 phosphorylation and colonic levels of TNF-α and LTB4. These data indicated that Gln ameliorated DSS-induced colitis via MKP-1 induction.


Assuntos
Colite/induzido quimicamente , Sulfato de Dextrana/toxicidade , Fosfatase 1 de Especificidade Dupla/metabolismo , Indução Enzimática/efeitos dos fármacos , Glutamina/uso terapêutico , Animais , Colite/tratamento farmacológico , Fosfatase 1 de Especificidade Dupla/genética , Camundongos , Organismos Livres de Patógenos Específicos
15.
Int J Nanomedicine ; 12: 8143-8158, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29184404

RESUMO

Graphene oxide (GO) is a nanomaterial with newly developing biological applications. Autophagy is an intracellular degradation system that has been associated with the progression of neurodegenerative disorders. Although induction of autophagic flux by GO has been reported, the underlying signaling pathway in neurodegenerative disorders and how this is involved in neuroprotection remain obscure. We show that GO itself activates autophagic flux in neuronal cells and confers a neuroprotective effect against prion protein (PrP) (106-126)-mediated neurotoxicity. GO can be detected in SK-N-SH neuronal cells, where it triggers autophagic flux signaling. GO-induced autophagic flux prevented PrP (106-126)-induced neurotoxicity in SK-N-SH cells. Moreover, inactivation of autophagic flux blocked GO-induced neuroprotection against prion-mediated mitochondrial neurotoxicity. This is the first study to demonstrate that GO regulates autophagic flux in neuronal cells, and that activation of autophagic flux signals, induced by GO, plays a neuroprotective role against prion-mediated mitochondrial neurotoxicity. These results suggest that the nanomaterial GO may be used to activate autophagic flux and could be used in neuroprotective strategies for treatment of neurodegenerative disorders, including prion diseases.


Assuntos
Autofagia/efeitos dos fármacos , Grafite/farmacologia , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Fragmentos de Peptídeos/toxicidade , Príons/toxicidade , Linhagem Celular , Grafite/química , Humanos , Mitocôndrias/metabolismo , Neurônios/patologia , Fármacos Neuroprotetores/química , Óxidos/química , Transdução de Sinais/efeitos dos fármacos
16.
Front Hum Neurosci ; 11: 295, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28638330

RESUMO

Prior research with preschool children has established that dialogic or active book reading is an effective method for expanding young children's vocabulary. In this exploratory study, we asked whether similar benefits are observed when a robot engages in dialogic reading with preschoolers. Given the established effectiveness of active reading, we also asked whether this effectiveness was critically dependent on the expressive characteristics of the robot. For approximately half the children, the robot's active reading was expressive; the robot's voice included a wide range of intonation and emotion (Expressive). For the remaining children, the robot read and conversed with a flat voice, which sounded similar to a classic text-to-speech engine and had little dynamic range (Flat). The robot's movements were kept constant across conditions. We performed a verification study using Amazon Mechanical Turk (AMT) to confirm that the Expressive robot was viewed as significantly more expressive, more emotional, and less passive than the Flat robot. We invited 45 preschoolers with an average age of 5 years who were either English Language Learners (ELL), bilingual, or native English speakers to engage in the reading task with the robot. The robot narrated a story from a picture book, using active reading techniques and including a set of target vocabulary words in the narration. Children were post-tested on the vocabulary words and were also asked to retell the story to a puppet. A subset of 34 children performed a second story retelling 4-6 weeks later. Children reported liking and learning from the robot a similar amount in the Expressive and Flat conditions. However, as compared to children in the Flat condition, children in the Expressive condition were more concentrated and engaged as indexed by their facial expressions; they emulated the robot's story more in their story retells; and they told longer stories during their delayed retelling. Furthermore, children who responded to the robot's active reading questions were more likely to correctly identify the target vocabulary words in the Expressive condition than in the Flat condition. Taken together, these results suggest that children may benefit more from the expressive robot than from the flat robot.

17.
ACS Nano ; 10(11): 10446-10453, 2016 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-27783894

RESUMO

Modulation of the carrier concentration and electronic type of monolayer (1L) MoS2 is highly important for applications in logic circuits, solar cells, and light-emitting diodes. Here, we demonstrate the tuning of the electronic properties of large-area 1L-MoS2 using graphene oxide (GO). GO sheets are well-known as hole injection layers since they contain electron-withdrawing groups such as carboxyl, hydroxyl, and epoxy. The optical and electronic properties of GO-treated 1L-MoS2 are dramatically changed. The photoluminescence intensity of GO-treated 1L-MoS2 is increases by more than 470% compared to the pristine sample because of the increase in neutral exciton contribution. In addition, the A1g peak in Raman spectra shifts considerably, revealing that GO treatment led to the formation of p-type doped 1L-MoS2. Moreover, the current vs voltage (I-V) curves of GO-coated 1L-MoS2 field effect transistors show that the electron concentration of 1L-MoS2 is significantly lower in comparison with pristine 1L-MoS2. Current rectification is also observed from the I-V curve of the lateral diode structure with 1L-MoS2 and 1L-MoS2/GO, indicating that the electronic structure of MoS2 is significantly modulated by the electron-withdrawing functional group of GO.

18.
Top Cogn Sci ; 8(2): 481-91, 2016 04.
Artigo em Inglês | MEDLINE | ID: mdl-26945492

RESUMO

Children ranging from 3 to 5 years were introduced to two anthropomorphic robots that provided them with information about unfamiliar animals. Children treated the robots as interlocutors. They supplied information to the robots and retained what the robots told them. Children also treated the robots as informants from whom they could seek information. Consistent with studies of children's early sensitivity to an interlocutor's non-verbal signals, children were especially attentive and receptive to whichever robot displayed the greater non-verbal contingency. Such selective information seeking is consistent with recent findings showing that although young children learn from others, they are selective with respect to the informants that they question or endorse.


Assuntos
Comportamento de Busca de Informação , Desenvolvimento Infantil , Pré-Escolar , Comportamento de Escolha , Feminino , Humanos , Masculino , Robótica
19.
Nanoscale ; 7(38): 15695-700, 2015 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-26350352

RESUMO

This study characterizes the effects of incident infrared (IR) radiation on the electrical conductivity of graphene oxide (GO) and examines its potential for mid-IR detection. Analysis of the mildly reduced GO (m-GO) transport mechanism near room temperature reveals variable range hopping (VRH) for the conduction of electrons. This VRH behavior causes the m-GO resistance to exhibit a strong temperature dependence, with a large negative temperature coefficient of resistance of approximately -2 to -4% K(-1). In addition to this hopping transport, the presence of various oxygen-related functional groups within GO enhances the absorption of IR radiation significantly. These two GO material properties are synergically coupled and provoke a remarkable photothermal effect within this material; specifically, a large resistance drop is exhibited by m-GO in response to the increase in temperature caused by the IR absorption. The m-GO bolometer effect identified in this study is different from that exhibited in vanadium oxides, which require added gold-black films that function as IR absorbers owing to their limited IR absorption capability.

20.
Sci Rep ; 5: 11216, 2015 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-26053892

RESUMO

We introduce a high-performance molecular sensor using self-corrugated chemically modified graphene as a three dimensional (3D) structure that indicates anisotropic charge distribution. This is capable of room-temperature operation, and, in particular, exhibiting high sensitivity and reversible fast response with equilibrium region. The morphology consists of periodic, "cratered" arrays that can be formed by condensation and evaporation of graphene oxide (GO) solution on interdigitated electrodes. Subsequent hydrazine reduction, the corrugated edge area of the graphene layers have a high electric potential compared with flat graphene films. This local accumulation of electrons interacts with a large number of gas molecules. The sensitivity of 3D-graphene sensors significantly increases in the atmosphere of NO2 gas. The intriguing structures have several advantages for straightforward fabrication on patterned substrates, high-performance graphene sensors without post-annealing process.

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