RESUMO
The CUP array of germanium (CAGe) is an array of fourteen high-purity germanium (HPGe) detectors. The detection efficiency of full-energy-peak emitted from the various samples assayed on the CAGe was calculated using the Monte Carlo simulation toolkit GEANT4. If the dead layer on the surface of the crystal is treated in the simulation as a continuous part of the active crystal, then the detection efficiency will be overestimated. Thus, the detection efficiency of the CAGe was adjusted using multi-nuclide source data and Monte Carlo simulations. The gamma spectra of the known activity source were obtained for each HPGe detector of the CAGe. The detection efficiency measured by the multi-source data was smaller than that of simulation data if the simulation treated the whole volume of germanium crystals as active for gamma detection. By optimizing the dead layers' thicknesses in the simulation, the detection efficiency calculated by the simulation could be matched to that of multi-source data.
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Pressurized intraperitoneal aerosol chemotherapy, named PIPAC, is now used in many centers around the world and as an intraperitoneal drug delivery system for treatment of peritoneal carcinomatosis. Recently, many of us have encountered problems during PIPAC procedures due to changes in material and production features of the original PIPAC nebulizer. Concomitantly, new PIPAC nebulizers proposed by other manufacturers are being launched on the market; which claim that they are the same as the original device in delivering PIPAC. However, these new devices are all different in terms of materials, technical characteristics and costs. We have considered that, to maintain the acquired results of PIPAC, we must ensure that the new systems are equivalent. The characteristics deemed essential by the expert group are as follows: 1: The nebulizer must be able to create droplets through an injector pressure between 10 and 20 bars, 2: The mean droplet size must be 3 micrometers, with 95% of the droplets between 0 and 10 micrometers, 3: The diffusion angle must be 70 degrees, which is the minimum.
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Neoplasias Peritoneais , Humanos , Aerossóis/uso terapêutico , Neoplasias Peritoneais/tratamento farmacológico , Nebulizadores e VaporizadoresRESUMO
To evaluate national epidemiologic data on infants treated for patent ductus arteriosus (PDA) in Korea and analyze outcomes associated with different PDA treatments. We retrospectively evaluated data on 12,336 patients diagnosed with PDA (International Classification of Diseases-10 code: Q250) between 2015 and 2018 from the Health Insurance Review and Assessment database. Among them, 1623 patients underwent surgical ligation (code: O1671). We used birth certificate data from Statistics Korea to estimate the prevalence, diagnosis, and treatment of PDA. The prevalence of infants with PDA was 81 infants per 10,000 live births and 45.2% in very low birth weight (VLBW) infants, which increased from 2015 to 2018. PDA ligation was performed in 2571 infants and 22% VLBW infants. Medical treatment was administered to 4202 infants, which decreased significantly, especially in VLBW infants (62% to 53%). The proportion of treatment was as follows: conservative treatment (53.1%), intravenous ibuprofen (24.4%), surgery (20.4%), and oral ibuprofen (10.7%); that among 4854 VLBW infants was as follows: intravenous ibuprofen (46.3%), conservative treatment (33.2%), surgery (22.2%), and oral ibuprofen (14.2%). Surgical treatment had a significantly higher risk (odds ratio 1.36) of mortality than conservative treatment. Surgical and/or medical treatments were associated with a higher risk of morbidity. Recently, increased use of conservative management of PDA has contributed to improved neonatal outcomes in VLBW infants. Select patients may still benefit from surgical ligation following careful consideration.
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Permeabilidade do Canal Arterial/complicações , Permeabilidade do Canal Arterial/terapia , Tomada de Decisão Clínica , Terapia Combinada/métodos , Terapia Combinada/tendências , Gerenciamento Clínico , Permeabilidade do Canal Arterial/diagnóstico , Permeabilidade do Canal Arterial/epidemiologia , Humanos , Recém-Nascido , Razão de Chances , Avaliação de Resultados em Cuidados de Saúde , PrevalênciaAssuntos
Pessoal Administrativo/psicologia , COVID-19/epidemiologia , Corpo Clínico Hospitalar/psicologia , Recursos Humanos de Enfermagem Hospitalar/psicologia , Esgotamento Profissional/epidemiologia , Fadiga de Compaixão/epidemiologia , Cirurgia Geral , Humanos , Estresse Ocupacional/epidemiologia , Pandemias , Inquéritos e QuestionáriosAssuntos
Betacoronavirus , Infecções por Coronavirus/epidemiologia , Transmissão de Doença Infecciosa/prevenção & controle , Pandemias , Pneumonia Viral/epidemiologia , Garantia da Qualidade dos Cuidados de Saúde/métodos , Procedimentos Cirúrgicos Operatórios/normas , COVID-19 , Humanos , Fatores de Risco , SARS-CoV-2 , SingapuraRESUMO
AIMS: Interaction between programmed death-1 ligand (PD-L1) and its receptor programmed death 1 (PD-1) on T cells inactivates antitumour immune responses. PD-L1 expression has been associated with poor prognosis in renal cell carcinoma (RCC) and predicts adverse outcome. This study was designed to evaluate the impact of PD-L1 expression and the immune microenvironment on the clinical outcome in Xp11 translocation renal cell carcinoma (TRCC) and, therefore, their potential relevance as prognostic biomarkers. METHODS AND RESULTS: The present retrospective analysis investigated expression of PD-L1 and immune cells CD8, CD4, CD3, forkhead box protein 3 (FoxP3) and PD-1 in TRCC compared to other types of RCC. FFPE specimens were collected between 2011 and 2017 from 311 patients who underwent nephrectomy at our institution for RCC. Specimens were immunostained for PD-L1, CD8, CD4, CD3, FoxP3 and PD-1, and an outcome analysis was conducted. PD-L1 expression rate was highest in TRCC (68%, 16 of 25), followed by mucinous tubular and spindle cell RCC and collecting duct carcinoma (33%, one of three), papillary RCC (27%, seven of 26), clear cell RCC (16%, 29 of 233), chromophobe RCC (11%, two of 18) and multilocular cystic RCC (0%, none of three). In TRCC, PD-L1 expression was associated with poor recurrence-free survival (RFS) (P = 0.041). The CD4high and FoxP3high groups showed a significantly shorter RFS (P = 0.05 and P = 0.031, respectively) compared to CD4low and FOXPlow groups. CONCLUSION: PD-L1 expression was higher in TRCC than in other types of RCC. High PD-L1 tumour cell expression and tumour infiltration by CD4+ and FoxP3+ immune cells were associated with poor RFS in TRCC.
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Antígeno B7-H1/biossíntese , Linfócitos T CD4-Positivos/imunologia , Carcinoma de Células Renais/imunologia , Neoplasias Renais/imunologia , Linfócitos do Interstício Tumoral/imunologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/patologia , Cromossomos Humanos X/genética , Feminino , Fatores de Transcrição Forkhead/imunologia , Humanos , Neoplasias Renais/genética , Neoplasias Renais/patologia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , Translocação Genética , Microambiente Tumoral/imunologiaRESUMO
In this retrospective study, we investigate the frequency and types of psychiatric disorders and their relationship to systemic manifestations in a cohort of 391 Ehlers-Danlos syndromes (EDS) and hypermobility spectrum disorder (HSD) patients based on the current 2017 International Classification of EDS diagnostic criteria. A detailed, systematic retrospective chart review was undertaken for patients assessed for HSD or EDS at two Canadian health centres. Patients were diagnosed according to the Villefranche criteria and reclassified for this study according to the 2017 International Classification of EDS. Data validation and statistical analyses were conducted. Psychiatric disorders were very common, with 49.4% of the total cohort affected; 28.9% reported multiple psychiatric diagnoses. Mood (34.5%) and somatoform (28.6%) disorders were most common. Interestingly, attention-deficit/hyperactivity disorder (ADHD) was significantly enriched in the HSD, but not EDS cohort (p = 0.0002, 95% CI 3.48-9.00) compared to the general population. There were no differences in the systemic associations with having psychiatric manifestations in the HSD compared to the EDS subsets. Muscle/body pain (OR 1.99) and gastrointestinal dysfunction (OR 2.07) were significantly associated with having mood disorders, and gastrointestinal dysfunction (OR 2.61) and nerve-related pain (OR 3.27) were associated with having somatoform disorders across the cohort. The common systemic associations with the presence of psychiatric manifestations in both HSD and EDS reaffirm that the conditions should be treated as a spectrum rather than as wholly separate entities, particularly with respect to psychiatric management. EDS and HSD patients share common psychiatric presentations, though ADHD is more common with HSD.
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Síndrome de Ehlers-Danlos/epidemiologia , Gastroenteropatias/epidemiologia , Instabilidade Articular/epidemiologia , Transtornos Mentais/epidemiologia , Dor/epidemiologia , Adulto , Comorbidade , Síndrome de Ehlers-Danlos/fisiopatologia , Síndrome de Ehlers-Danlos/psicologia , Feminino , Gastroenteropatias/fisiopatologia , Gastroenteropatias/psicologia , Humanos , Instabilidade Articular/fisiopatologia , Instabilidade Articular/psicologia , Masculino , Transtornos Mentais/fisiopatologia , Transtornos Mentais/psicologia , Pessoa de Meia-Idade , Dor/fisiopatologia , Dor/psicologia , Prevalência , Estudos Retrospectivos , Adulto JovemRESUMO
The leaves of Vaccinium bracteatum Thunb. are a source of traditional herbal medicines found in East Asia. The present study aimed to evaluate the mechanisms underlying the antidepressant-like effects of water extract of V. bracteatum Thunb. leaves (VBLW) in a mouse model of chronic restraint stress (CRS) and to identify the possible molecular in vitro mechanisms of the neuroprotective effects. The CRS-exposed mice were orally administered VBLW (100 and 200 mg/kg) daily for 21 days consecutively. The behavioral effects of VBLW were assessed through the forced swim test (FST) and the open field test (OFT). The levels of serum corticosterone (CORT), corticotropin releasing hormone (CRH), and adrenocorticotropin hormone (ACTH), brain monoamines, such as serotonin, dopamine, and norepinephrine, and serotonin turnover by tryptophan hydroxylase 2 (TPH2), serotonin reuptake (SERT), and monoamine oxidase A (MAO-A) were evaluated, in addition to the extracellular signal-regulated kinases (ERKs)/protein kinase B (Akt) signaling pathway. CRS-exposed mice treated with VBLW (100 and 200 mg/kg) showed significantly reduced immobility time and increased swimming and climbing times in the FST, and increased locomotor activity in the OFT. Moreover, CRS mice treated with VBLW exhibited significantly decreased CORT and ACTH, but enhanced brain monoamine neurotransmitters. In addition, CRS mice treated with VBLW had dramatically decreased protein levels of MAO-A and SERT, but increased TPH2 protein levels in the hippocampus and the PFC. Similarly, VBLW significantly upregulated the ERKs/Akt signaling pathway in the hippocampus and the PFC. Furthermore, VBLW showed neuroprotective effects via increased CREB phosphorylation in CORT-induced cell injury that were mediated through the ERK/Akt/mTOR signaling pathways. These results suggested that the antidepressant-like effects of VBLW might be mediated by the regulation of the HPA axis, glucocorticoids, and serotonin turnover, such as TPH2, SERT, and MAO-A, as well as the concentration of monoamine neurotransmitters, and the activities of ERK and Akt phosphorylation, which were possibly associated with neuroprotective effects.
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BACKGROUND: Obesity is a major component of metabolic syndrome and an independent risk factor for various chronic diseases. It is also closely associated with mental illness, and the interaction is complex and multifactorial. This study aimed to estimate the prevalence of anxiety and depressive symptoms among obese Singaporeans. METHODS: Cross-sectional data of 36 male and 47 female obese Singaporeans who had been referred to the weight management clinic of National University Hospital, Singapore, between January 2010 and November 2011 were collected. Obesity was classified according to criteria of the World Health Organization. The extents of anxiety and depressive symptoms were measured using the Hospital Anxiety and Depression Scale. RESULTS: In obese Singaporeans attending the weight management clinic, the prevalence of anxiety symptoms was higher than that of depressive symptoms (28% vs 11%). There was no major socioeconomic difference between obese patients with and without anxiety, or with and without depressive symptoms. CONCLUSION: In obese Singaporeans, anxiety symptoms may be more common than depressive symptoms. Weight management programmes should incorporate anxiety management as part of standard treatment. Early detection and pharmacological and psychological interventions should be implemented.
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Ansiedade/epidemiologia , Depressão/epidemiologia , Obesidade/epidemiologia , Adulto , Comorbidade , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Singapura/epidemiologiaRESUMO
OBJECTIVE: We aimed to determine the factors contributing toward diffusely increased renal uptake on bone scintigraphy using technetium-99m (Tc-99m) diphosphono-propanedicarboxylic acid (DPD) in patients with end-stage renal disease. PATIENTS AND METHODS: One-hundred and forty-three bone scintigraphies, performed between June 2007 and July 2013, in 135 patients with chronic kidney disease were analyzed retrospectively, including 22 bone scintigraphies (15 patients; eight women; seven men) with glomerular filtration rates less than 15 ml/min/1.73 m. Patients with nephrocalcinosis were excluded. The clinical records of medication and underlying disease were reviewed retrospectively. The presence of renal artery calcification was visually estimated and the Hounsfield unit (HU) of renal parenchyma was measured by abdominal and pelvic nonenhanced computed tomography. RESULTS: Two patients underwent peritoneal dialysis and 13 underwent hemodynamic dialysis. Diffusely increased renal Tc-99m DPD uptake was observed on 15 of 22 (68%) bone scintigraphy images. Laboratory test results were not significantly different between the patients with or without increased renal uptake. A history of inflammatory conditions or antibiotic administration did not correlate with kidney visualization. The significant factor for diffuse renal tracer uptake on multivariate analysis was renal artery calcification (odds ratio: 18.42; 95% confidence interval: 2.01-79.43; P<0.001). The mean HU values were significantly higher in patients with diffuse renal tracer uptake (P=0.04) and renal artery calcification (P=0.02). CONCLUSION: Small renal arteriolar calcification and a higher HU value of renal parenchyma could be associated with diffusely increased renal Tc-99m DPD uptake in patients with end-stage renal disease.
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Osso e Ossos/diagnóstico por imagem , Falência Renal Crônica/diagnóstico por imagem , Falência Renal Crônica/metabolismo , Rim/metabolismo , Compostos de Organotecnécio/metabolismo , Adulto , Idoso , Artefatos , Transporte Biológico , Difusão , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
BACKGROUND: The purpose of this study is to identify predictive markers for abnormal glucose metabolism in Korean women with polycystic ovary syndrome (PCOS). METHODSË A total of 312 PCOS patients were evaluated. All patients underwent 75-g oral glucose tolerance tests. The 2-hour plasma glucose level was used to categorize subjects as impaired glucose tolerance (IGT) or non-insulin-dependent diabetes mellitus (NIDDM). Areas under the receiver operating characteristic (ROC) curves were used to compare the power of serum markers. Multiple linear regression analysis was used to evaluate the contribution of each confounding factor to the 2-hour post-load glucose value. RESULTSË A total of 285 PCOS women with normal glucose tolerance (91.3%) and 27 PCOS patients with abnormal glucose metabolism (8.7%) (IGT/NIDDM) were evaluated. Area under the curve (AUC) of hemoglobin (Hb) A1c, high-sensitivity C-reactive protein (hs-CRP), lipid accumulation product (LAP) index, and triglyceride (TG) were 0.780, 0.772, 0.762, and 0.758 respectively. ROC analysis suggested a threshold value of 5.45 in HbA1c (71.4% sensitivity and 70.0% specificity), a value of 1.16 in hs-CRP (70.3% sensitivity and 80.1% specificity), a value of 12.98 in LAP index (88.5% sensitivity and 52.3% specificity) and a value of 88.0 in TG (77.8% sensitivity and 63.5% specificity) to predict for abnormal glucose metabolism. CONCLUSIONSË HbA1c, hs-CRP, LAP index, and TG could be useful predictive markers for abnormal glucose metabolism (IGT/NIDDM) in Korean PCOS women.
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Intolerância à Glucose/sangue , Intolerância à Glucose/complicações , Síndrome do Ovário Policístico/complicações , Adulto , Biomarcadores/sangue , Feminino , Intolerância à Glucose/diagnóstico , Humanos , Síndrome do Ovário Policístico/sangue , Valor Preditivo dos Testes , Estudos ProspectivosRESUMO
BACKGROUND: In many countries, gastric cancer is not diagnosed until an advanced stage. An Internet-based e-learning system to improve the ability of endoscopists to diagnose gastric cancer at an early stage was developed and was evaluated for its effectiveness. METHODS: The study was designed as a randomized controlled trial. After receiving a pre-test, participants were randomly allocated to either an e-learning or non-e-learning group. Only those in the e-learning group gained access to the e-learning system. Two months after the pre-test, both groups received a post-test. The primary endpoint was the difference between the two groups regarding the rate of improvement of their test results. FINDINGS: 515 endoscopists from 35 countries were assessed for eligibility, and 332 were enrolled in the study, with 166 allocated to each group. Of these, 151 participants in the e-learning group and 144 in the non-e-learning group were included in the analysis. The mean improvement rate (standard deviation) in the e-learning and non-e-learning groups was 1·24 (0·26) and 1·00 (0·16), respectively (P<0·001). INTERPRETATION: This global study clearly demonstrated the efficacy of an e-learning system to expand knowledge and provide invaluable experience regarding the endoscopic detection of early gastric cancer (R000012039).
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Gastroenterologistas/educação , Desenvolvimento de Programas , Neoplasias Gástricas/diagnóstico , Detecção Precoce de Câncer , Gastroenterologistas/psicologia , Gastroscopia , Humanos , Internet , Aprendizagem , Avaliação de Programas e Projetos de SaúdeRESUMO
Buschke-Ollendorff syndrome (BOS) is a rare, often benign, autosomal skin disorder. BOS commonly presents with nontender connective tissue naevi and sclerotic bony lesions (osteopoikilosis [OPK]). Herein, we summarize the presenting features of BOS and potential associations by conducting a systematic review of the literature and summarizing a cohort seen at the Hospital for Sick Children (HSC), Toronto, Canada. PubMed was searched using the following terms: 'BOS'; 'dermatofibrosis lenticularis'; 'OPK'; 'LEMD3'; 'elastoma'; 'collagenoma'. Only case reports were included, without date or language restrictions. Cases were further narrowed to those where patients or their families had a combination of skin and bony lesions, or a positive genetic test. Data were summarized using frequencies. In total, 594 reports were discovered, of which 546 (92%) were excluded. The remaining 48 accounted for 164 cases. Skin lesions were noted in 24% of cases and bony lesions in 20%, while 54% of patients had both. In 1% of cases the diagnosis was made on genetic testing alone. A family history was noted in 92% of cases. All patients with spinal stenosis (2%) or shortened status (7%) had OPK. Six per cent of patients had neurological problems. However, 50% of the cohort from HSC had cognitive delays, and only cases from 2007 onwards reported cognitive delays (the prevalence was 17% among those cases). This review confirms the classical diagnostic features of BOS. In addition, it highlights a previously unreported association between a shortened stature and OPK, as well as a possible association with cognitive delays.
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Osteopecilose/diagnóstico , Dermatopatias Genéticas/diagnóstico , Adolescente , Adulto , Distribuição por Idade , Idade de Início , Idoso , Criança , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteopecilose/complicações , Dermatopatias Genéticas/complicações , Adulto JovemRESUMO
BACKGROUND: Patients undergoing laparoscopic gynecological surgery are at high risk of postoperative nausea and vomiting (PONV). We compared the antiemetic efficacy of ondansetron plus betahistine with that of ondansetron alone in this patient population. METHODS: In this randomized, double-blinded study, 168 patients were randomly allocated to receive placebo (O group) or betahistine 18 mg (OB group) orally 3 hours before surgery and 24 hours thereafter. In both groups, ondansetron 4 mg was administered at the end of surgery and 8 mg were added to an intravenous patient-controlled analgesia (IV-PCA) fentanyl solution. The primary outcome was complete response (no PONV and no rescue antiemetics) during the first 48 hours after surgery. The severity of nausea, pain score, and adverse events were assessed. RESULTS: The incidence of complete response was significantly higher in OB group than in O group (69% vs. 46%, P=0.004). The severity of nausea was lower in OB group than in O group during 30 minutes to 6 hours and 6 to 24 hours after surgery (P=0.001 and P<0.001). Pain score was similar between the groups. The incidence of dizziness was lower in OB group than in O group (13% vs. 40%, P < 0.001). Six patients (7%) in OB group and 15 patients (18%) in O group required early IV-PCA discontinuation, primarily because of PONV and/or dizziness (P=0.038). CONCLUSIONS: Compared to ondansetron alone, ondansetron plus betahistine was more effective to prevent PONV and dizziness in high-risk patients undergoing laparoscopic gynecological surgery.
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Antieméticos/uso terapêutico , beta-Histina/uso terapêutico , Laparoscopia/efeitos adversos , Ondansetron/uso terapêutico , Náusea e Vômito Pós-Operatórios/tratamento farmacológico , Adulto , Idoso , Antieméticos/efeitos adversos , beta-Histina/efeitos adversos , Método Duplo-Cego , Esquema de Medicação , Quimioterapia Combinada/métodos , Feminino , Procedimentos Cirúrgicos em Ginecologia , Humanos , Pessoa de Meia-Idade , Ondansetron/efeitos adversos , Medição da Dor , Estudos Prospectivos , Índice de Gravidade de Doença , Adulto JovemAssuntos
Conservadores da Densidade Óssea/economia , Análise Custo-Benefício/métodos , Custos de Cuidados de Saúde , Osteoporose Pós-Menopausa/tratamento farmacológico , Fatores Etários , Idoso , Conservadores da Densidade Óssea/uso terapêutico , Feminino , Fraturas do Quadril/economia , Fraturas do Quadril/epidemiologia , Fraturas do Quadril/etiologia , Hong Kong/epidemiologia , Humanos , Incidência , Cadeias de Markov , Pessoa de Meia-Idade , Osteoporose Pós-Menopausa/economia , Osteoporose Pós-Menopausa/mortalidade , Fraturas por Osteoporose/economia , Fraturas por Osteoporose/epidemiologia , Anos de Vida Ajustados por Qualidade de Vida , Fraturas da Coluna Vertebral/economia , Fraturas da Coluna Vertebral/epidemiologia , Fraturas da Coluna Vertebral/etiologia , Fatores de Tempo , Traumatismos do Punho/economia , Traumatismos do Punho/epidemiologia , Traumatismos do Punho/etiologiaRESUMO
BACKGROUND: The utility of computed tomography scans of the thorax, abdomen, and pelvis for gastric cancer staging has been recommended in many countries. However, the validity of the use of computed tomography thorax in gastric cancer staging has not been challenged. METHODS: A retrospective review was conducted on our gastric cancer registry from 1998 till 2012 in the National University Hospital, Singapore. We performed computed tomography thorax only in selected cases. We defined isolated lung metastasis as the presence of suspicious findings on computed tomography thorax in the absence of metastasis elsewhere. RESULTS: A total of 808 gastric cancer cases were reviewed. The mean age of the patients was 66 years (standard deviation 13.53), and 67% were male. In all, 238 patients (30%) had metastatic disease at presentation, and 1 (0.42%) had isolated lung metastasis. The most common site of metastasis was intra-abdominal (73.8%). Among the patients who underwent surgery, the overall distant recurrence rate was 30%, of which only 83 (30%) patients had lung metastasis and all had concurrent metastasis in an intra-abdominal site. CONCLUSION: The rarity of isolated lung metastasis in gastric cancer suggests the limited value of computed tomography thorax as a routine staging tool for gastric cancers.
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Tomografia Computadorizada Multidetectores/métodos , Estadiamento de Neoplasias/métodos , Radiografia Torácica/métodos , Neoplasias Gástricas/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Gastrectomia , Humanos , Incidência , Neoplasias Pulmonares/diagnóstico por imagem , Neoplasias Pulmonares/epidemiologia , Neoplasias Pulmonares/secundário , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/epidemiologia , Prognóstico , Reprodutibilidade dos Testes , Estudos Retrospectivos , Singapura/epidemiologia , Neoplasias Gástricas/patologia , Neoplasias Gástricas/cirurgia , Adulto JovemRESUMO
In this paper, we test the performance of a quasi-optical, internal-gyrotron mode converter. When cold testing mode converters, a rotating higher-order mode is commonly used. However, this requires a nontrivial design and precise alignment. We thus propose a new technique for testing gyrotron mode converters by using a simple, non-rotating, higher-order mode generator. We demonstrate the feasibility of this technique for a W-band gyrotron quasi-optical mode converter by examining the excitation of a TE6,2 mode from a non-rotating mode generator. Our results demonstrate that this new cold-test scheme is an easy and efficient method for verifying the performance of quasi-optical mode converters.