13,023 research outputs found
An exploration into Gen Ys attitudes and behaviour towards volunteering whilst backpacking
No full textThis study focuses on Generation Ys’ attitudes and behaviour towards engaging in volunteer tourism whilst backpacking. To that end, we first examine Gen Ys’ generational characteristics and the predominant attitudes and behaviours displayed by this generational cohort. Then the focus is shifted to understanding Generation Y as backpackers and their internal and external motivations. These motivations are queried under the prism of volunteer tourism; being seen as factors determining the level of engagement with volunteer tourism and overall backpacking behaviour while travelling. This chapter provides insights into the themes described above by examining the relevant tourism literature. Finally, it summarises the theoretical gaps in the extant literature and sets objectives for future research, whilst signposting authors to key literature sources
Neural correlates and gait characteristics for hypoxic-ischemic brain injury induced freezing of gait
No full textOBJECTIVE: To investigate gait characteristics in patients with freezing of gait (FOG) after hypoxic-ischemic brain injury (HIBI) and to elucidate neural correlates for FOG using F-18 fluoro-2-deoxy-d-glucose positron emission tomography. METHODS: We enrolled 12 patients with FOG after HIBI and 17 patients without FOG after HIBI. We performed three-dimensional gait analyses and compared each parameter and gait variability. Brain metabolism was measured, and we compared regional brain metabolism using a voxel-by-voxel-based statistical mapping analysis. RESULTS: The FOG group revealed a significantly decreased joint range of motion (ROM), particularly in the sagittal plane for three-joint summated ROM (p<0.0025). Spatiotemporal results demonstrated that stride length and step length were decreased in the with FOG group (p<0.005). FOG severity was negatively correlated with brain metabolism in the left thalamus, and three-joint summated ROM in the sagittal plane was positively associated with brain metabolism in the left thalamus and midbrain (p<0.05). CONCLUSIONS: Central organizational level amplitude disorder may play an important role in the pathophysiology, and disturbance in the cholinergic pathway might contribute to the development of FOG in patients with HIBI. SIGNIFICANCE: These findings contribute to understanding FOG in HIBI
Incidental Detection of Meningioma on 18F-Flutemetamol PET
No full textMeningioma is typically a benign tumor that may incidentally be found on imaging. This case demonstrates the utility of 18 F-flutemetamol (FMM) PET/CT in an 80-year-old woman evaluated for memory decline. Although the scan was performed for dementia assessment, it revealed an incidental mass in the frontal region. Early-phase PET showed relatively low uptake, while delayed-phase imaging displayed intense uptake of 18 F-FMM. Magnetic resonance imaging and surgical pathology confirmed the lesion as a meningioma. This report may aid in interpreting incidental mass lesions on 18 F-FMM PET, providing a reference for physicians who may encounter similar findings
A HIGH-SPEED SI BIPOLAR-TRANSISTOR WITH SAVEN - (SELF-ALIGNED DEVICE USING VERTICAL NITRIDE)
No full textThis paper presents a new device called SAVEN (self-aligned device using vertical nitride) which has faster switching speed characteristics. To obtain this level of performance, SAVEN adapts the technology reducing the extrinsic base region by controlling the vertical nitride layer. Also, it uses the trench isolation and TiSi2 process of the n+ polysilicon emitter region. The emitter area is designed to be 1.0 x 4.0 mum2. DC characteristics of the fabricated transistor is evaluated and analyzed for the SPICE input parameters. The current gain of the butted npn transistor is around 100, and the breakdown voltage for the collector-to-emitter is 7.5 V. The junction capacitances of base-to-collector and collector-to-substrate are measured at 12 fF and 19 fF, respectively. These low values are due to the small extrinsic base width and elimination of the parasitic capacitance between the epitaxial layer and substrate. From the measurement of the current mode logic (CML) ring oscillator with 31 stages, the minimum propagation delay time per gate is 45 ps at 1.4 mW.The authors are grateful to S.H.Chai, J.G.Koo and J.H.Lee for many helpful discussions. Also they would like to thank Korea Telecommunication (KT) for financial support
Combining Dopamine Transporter and Amyloid PET Tracer: A Preclinical Study on Dual-Target Imaging
No full textPURPOSE: This study aimed to evaluate the feasibility and diagnostic utility of a dual-target positron emission tomography (PET) imaging approach using a cocktail of N-3-[(18)F]fluoropropyl-2beta-carbomethoxy-3beta-(4-iodophenyl) nortropane ([(18)F]FP-CIT) and [(18)F]florbetaben (FBB) for the simultaneous assessment of dopaminergic and amyloid changes in a preclinical setting. PROCEDURES: We utilized both Parkinson's disease (PD) and Alzheimer's disease (AD) mouse models, as well as a control group, to investigate the uptake of [(18)F]FP-CIT and [(18)F]FBB individually and in combination. PET imaging was conducted, and standardized uptake value ratios (SUVRs) were analyzed for each model across the striatal and cortical regions. Comparisons were made between single and cocktail PET scans to assess potential cross-interference of the tracers. RESULTS: In both PD and AD models, no statistically significant differences were observed in the SUVRs between single-tracer and cocktail PET scans in the striatum and cortex (p > 0.4 for striatal comparisons, p > 0.8 for cortical comparisons). Bland-Altman analysis showed no significant bias, supporting the interchangeability of SUVRs between single and cocktail PET scans. CONCLUSIONS: This preclinical study suggests that [(18)F]FP-CIT and [(18)F]FBB PET imaging is a viable dual-target imaging approach for neurodegenerative disease evaluation. The method could streamline diagnostic workflows and improve patient convenience. Further clinical studies are warranted to validate the efficacy and safety of this approach in human populations
Comparative study of 18F-labeled PET radiopharmaceuticals in an Alzheimer’s disease mouse model
No full textAbstract Background Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that is the leading cause of dementia, characterized by memory loss, cognitive decline, and significant social and economic burdens. Despite extensive research into amyloid positron emission tomography (PET) radiopharmaceuticals, the effectiveness of various 18F-labeled tracers for imaging amyloid plaques in AD mouse models remains uncertain. This study aimed to evaluate the performance of three radiopharmaceuticals—18F-florbetaben (FBB), 18F-flutemetamol (FMM), and 18F-florapronol (FPN)—in differentiating amyloid deposition in AD and control mice. Results 18F-FMM and 18F-FBB demonstrated significantly higher standardized uptake value ratios (SUVRs) in AD mice than in controls. For 18F-FBB, the mean SUVR in AD mice was 1.06, significantly higher than the 0.81 in controls (p < 0.001). Similarly, 18F-FMM showed a mean SUVR of 0.97 in AD mice compared to 0.94 in controls (p = 0.024). In contrast, 18F-FPN did not show significant SUVR differences between AD and control groups (p = 0.071). Comparative analysis revealed that 18F-FBB exhibited a significantly greater SUVR difference between AD and control groups compared to 18F-FMM (p < 0.001). Conclusions 18F-FBB emerged as the most effective radiopharmaceutical for imaging amyloid deposition in AD mouse models, providing superior differentiation between AD and control groups. These findings support the optimization of amyloid PET tracers for preclinical studies, facilitating advancements in Alzheimer’s research. Clinical trial number Not applicable
Immune responses to the Mycoplasma hyopneumoniae P97 antigen in pigs vaccinated with Erysipelothrix rhusiopathiae YS-19
No full textWe investigated immune responses to the P97 antigen of Mycoplasma hyopneumoniae in pigs vaccinated with Erysipelothrix rhusiopathiae YS-19 strain expressing a recombinant protein of the P97 antigen on the cell surface. In the pigs that were intranasally immunized three times with the YS-19 stain, the P97-specific serum antibodies were not detected throughout the experimental period. However, after the third immunization, peripheral blood mononuclear cells (PBMC) from the YS-19-immunized pigs significantly proliferated when stimulated with the P97 protein, compared to the cells from non-immunized pigs. Furthermore, when stimulated with the P97 protein, production of IFN-γ, an indicator of cell-mediated immune responses, from PBMC of the YS-19-immunized pigs was observed after the challenge. Irrespective of the immunization of pigs with the YS-19 strain, PBMC produced IL-8 with stimulation with P97 protein, and exuded polymorphonuclear leukocytes were observed in the bronchoalveolar lavage fluid from the pigs that had been intranasally inoculated with P97 protein. In an experiment in which a needle-free injector was used for intradermal immunization, PBMC from the pigs immunized with the YS-19 strain significantly proliferated with stimulation with the P97 protein after a challenge with a virulent M. hyopneumoniae strain. In pigs immunized with the YS-19 strain using the needle-free injector, the severity of pneumonic lung lesions caused by M. hyopneumoniae infection was significantly reduced.Mycoplasma hyopneumoniae P97抗原の一部を菌体表面に発現する豚丹毒菌YS-19株免疫豚のP97抗原に対する免疫応答の解析を行った. YS-19株を3回経鼻的に免疫された豚では, P97抗原に対する血中抗体は検出されなかったが, 末梢血単核球は3回目の免疫直後からP97抗原刺激に対して増殖反応を示し, その程度は対照豚と比べて有意な差が認められた. また, M. hyopneumoniae強毒株攻撃接種後に採取した末梢血単核球はP97抗原刺激に対して細胞性免疫の重要な指標であるIFN-γを産生した. 免疫, 非免疫に拘わらず, 豚の末梢血単核球はP97抗原の刺激によりIL-8を産生し, P97抗原を鼻腔内に噴霧投与された豚では気管支肺胞洗浄液中に多量の好中球が観察された. さらに, YS-19株のNeedle-free injector（針なし注射）を用いたワクチン接種法の検討において, 皮内に1回免疫した豚の末梢血単核球は, M.hyopneumoniae強毒株攻撃接種後にP97抗原刺激による増殖能が有意に上昇した. なお, Needle-freeinjectorによるYS-19株免疫豚では肺炎病変の形成が有意に抑えられた.departmental bulletin pape
Normal presynaptic dopaminergic neurons in corticobasal syndrome with MAPT gene mutation
No full textSerial 18F-FP-CIT and FDG PET in Fulminant Corticobasal Syndrome
No full textCorticobasal syndrome (CBS) is characterized by a slow progressive cognitive decline, apraxia, myoclonus, dystonia, and parkinsonism. We experienced a rapidly progressing CBS patient (onset to bed-ridden within 2 years) presenting only with resting tremor but showing complete unilateral loss of dopamine transporter binding. This case exhibited distinct FDG PET findings involving the unilateral severe anterior frontal cortex, caudate nucleus, and contralateral cerebellum, which is different from classical CBS. However, to date, no detailed serial functional imaging study has been performed in rapidly progressing CBS, so these FDG PET and CIT PET findings may help clinicians to recognize this fulminant type of corticobasal degeneration
Striatal Hyperperfusion Observed in Dual-Phase 18F-FP-CIT PET Imaging of Hyperglycemic Chorea
No full textA 76-year-old woman with a history of diabetes mellitus presented with right-side dominant generalized chorea. At presentation, her blood glucose level was 500 mg/dL with an HbA1C of 11%. Because the patient had been on levodopa treatment from her primary physician, a dual-phase 18F-FP-CIT PET scan was performed. The early-phase images showed increased perfusion in the bilateral striatum, and the delayed-phase images revealed decreased uptake in the left caudate. Hyperperfusion in the striatum may indicate the acute phase of hyperglycemic chorea. This image illustrates the advantage of adding early-phase scans in 18F-FP-CIT PET in differentiating various hyperkinetic and hypokinetic disorders
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