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Background: Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is a rare autosomal dominant disease progressively affecting cognitive and motor functions, most often caused by mutations in the colony-stimulating factor 1 receptor gene (CSF1R). / Aim: To elucidate the mechanism of disease progression, changes in white matter lesions and cortical cerebral blood flow (CBF) were evaluated in cases during various stages of the disease. ...

Objectives: We reviewed surgical outcomes after introducing a novel surgical technique for anal fistula surgery designed to preserve anal sphincter function and the anoderm. Methods: We studied 200 male patients who underwent a functional preservative operative technique (FPOT group) for anal fistulas and 200 patients who underwent resection of trans-sphincteric anal fistulas (fistulectomy group) between February 2014 and September 2015. We compared complications, such as those affecting anal sphincter function, recurrence, and incontinence. Results: Fistulas recurred in three (1.5%) patients in the FPOT group and two (1%) patients in the fistulectomy group. This difference was not significant. Other complications included gas leakage and other forms of incontinence in 1 (0.5%) and 14 (7%) patients in the FPOT and fistulectomy groups, respectively. Anal function assessment demonstrated that the FPOT was significantly better at preserving function than fistulectomy in all patients. Conclusions: There were no significant differences between the FPOT and fistulectomy in terms of recurrence or complication rates. Also, because there was no decrease in postoperative anal function, we concluded that the FPOT is an effective preservative surgical technique for treating trans-sphincteric anal fistulas.

Objectives Ligation and excision remain the commonly recognized standard surgical modality for treating hemorrhoids. Further, impediments to surgical treatment owing to social factors and the need for minimally invasive procedures and other confounders have resulted in the adoption of the mucopexy-recto anal lifting (MuRAL) method which is associated with favorable outcomes. The objective of this study was to describe the procedure and report the outcomes in patients who underwent MuRAL. Methods Between March 2016 and February 2018, 55 patients (26 males and 29 females) underwent MuRAL for hemorrhoids and rectal mucosal prolapse. The duration of the surgical procedure and hospitalization, postoperative complications, and satisfaction were evaluated. Results The mean age of the male patients (n = 26) was 61.5 ± 4.9 years and that of the female patients (n = 29) was 61.5 ± 3.2 years. The mean duration of surgery was 46 ± 23 minutes for males and 53 ± 28 minutes for females, and the mean observation duration was 317 ± 186 days. Intraoperative hemorrhage was low for males and females. The mean hospitalization period was 3.2 ± 1.5 days for males and 4.3 ± 2.1 days for females. Differences in several postoperative complications were observed between male and female patients. Postoperative satisfaction was rated high by the patients. Conclusions Risks of hemorrhage and pain associated with the MuRAL method were low because the procedure does not involve incision or excision. Other than ligation and excision, recurrence is favorable compared with that of other surgical modalities for the treatment of hemorrhoids.

In this paper, we propose a system for improving the discussion skills of participants in a meeting by automatically evaluating statements in the meeting and effectively feeding back the results of the evaluation to them. To evaluate the skills automatically, the system uses both acoustic features and linguistic features of statements. It evaluates the way a person speaks, such as their “voice size,” on the basis of the acoustic features, and it also evaluates the contents of a statement, such as the “consistency of context,” on the basis of linguistic features. These features can be obtained from meeting minutes. Since it is difficult to evaluate the semantic contents of statements such as the “consistency of context,” we build a machine learning model that uses the features of minutes such as speaker attributes and the relationship of statements. In addition, we argue that participants’ heart rate (HR) data can be used to effectively evaluate their cognitive performance, specifically the performance in a discussion that consists of several Q&A segments (question-and-answer pairs). We collect HR data during a discussion in real time and generate machine-learning models for evaluation. We confirmed that the proposed method is effective for evaluating the discussion skills of meeting participants.

Creutzfeldt-Jakob disease (CJD) is a prion disease characterized by rapidly progressive dementia that is often followed by behavioral disturbances, ataxia, myoclonus, and akinetic mutism. The initial symptoms of CJD reportedly vary, but the onset is usually gradual. Here, we report a case of CJD with a sudden, stroke-like onset of right hemiparesis to alert readers that CJD can mimic a stroke during its early stage.

The phenomenon that the response of a nonlinear system to a weak input signal is optimized by the presence of a nonzero level of noise that occurs in the visual part of our brain. In this study, our purpose is to reveal whether depth perception of photographs increases with visual noise. We conducted an experiment to evaluate the depth perception of photographs with or without visual noise. We prepared two types of visual noises with three levels of amplitude. Results show that stimuli with visual noise were more frequently selected than those without noise, while the most effective noise depended on the photograph. It was suggested that depth perception was improved by appropriate noise of appropriate strength. The most effective noise might depend on the dominant depth clues in the photographs.

In statistical process control (SPC) there are two situations where monitoring multivariate is needed. One is that all of the variables monitored are product ones. The other is that the variables monitored are some product and process ones. In these cases, there are correlations among the variables. Therefore, application of multivariate control charts to such process control is useful.

Ti wire electrodes were immersed in acidic solutions containing H 2 SO 4 and HCl of various concentrations at 353 K to evaluate corrosion rate by measurement of electric resistance change (resistometry). Addition of hydrochloric acid to sulphuric acid solution promoted depassivation of Ti. After depassivation, the immersion potential dropped to the hydrogen evolution potential and a hydride layer was formed on the surface. The hydride layer dissolved continuously in the acidic solution. SEM observation showed that Ti wires dissolved almost uniformly in the early stage and that the dissolution then trace became irregular due to nonuniform growth of the hydride layer. Dissolution rate of a Ti wire was estimated almost accurately by resistometry.

Non-recurrent inferior laryngeal nerve (NRILN) is a rare embryologic anomaly that can increase the risk of injury during thyroid surgery. Although the association between the NRILN and an aberrant right subclavian artery has been reported, to date there have been no reports describing cases of NRILN with multiple vascular abnormalities. A 60-year-old man with papillary thyroid carcinoma and a history of right internal carotid artery occlusion by thrombosis was examined with magnetic resonance angiography (MRA). The right NRILN was found during a total thyroidectomy with surrounding lymph node dissection. MRA revealed an aberrant right subclavian artery and aplasia of the bilateral posterior communicating arteries composing the circle of Willis. This is the first clinical report demonstrating NRILN with multiple vascular abnormalities. Patients with NRILN must be examined for vascular anomalies and associated lesions such as aneurysms and thromboembolism.

Background Polymorphonuclear neutrophil (PMN)-dominated inflammation is prominent in the airways of subjects with cystic fibrosis (CF) and chronic bronchitis (CB). Interleukin (IL)-8, myeloperoxidase (MPO), and DNA are markers of neutrophilic inflammation. We hypothesized that sputum MPO, DNA, and IL-8 concentrations would negatively correlate with pulmonary function and sputum transportability. Methods We measured pulmonary function and analyzed sputum IL-8, MPO, and DNA concentrations, as well as the transport properties of sputum samples obtained from 16 subjects with CF and 15 subjects with CB. We also evaluated changes in these measurements in paired sputum samples from these subjects obtained 2 to 12 months apart. Results IL-8 and MPO concentrations in the sputum of CF subjects was inversely correlated with FEV 1 percent predicted (IL-8: r = −0.40; p = 0.003; MPO: r = −0.38; p = 0.003) and FVC percent predicted (IL-8: r = −0.4; p = 0.02; MPO: r = −0.4; p = 0.02). IL-8 and DNA concentrations were inversely correlated with sputum cough transportability (CTR) [IL-8: r = −0.4; p = 0.02; DNA: r = −0.36; p = 0.048]. Changes in DNA concentration in sputum samples from CF subjects over time were inversely correlated with changes in FEV 1 percent predicted ( r = −0.58; p = 0.02), FVC percent predicted ( r = −0.74; p = 0.002), and CTR ( r = −0.59; p = 0.02). There was no correlation among pulmonary function, sputum properties, and inflammatory markers in the sputum from subjects with CB. Conclusions The sputum concentrations of IL-8, MPO, and DNA appear to be closely associated with pulmonary function in subjects with CF but not in subjects with CB.

Study objectives: Inhalation of hypertonic saline or mannitol solutions acutely increases mucociliary clearance. Because increased clearance is often coupled with increased mucus secretion, we hypothesized that hyperosmolar agents would stimulate mucus secretion. Setting and subjects: The isolated tracheae of healthy young adult ferrets were studied in a basic research laboratory. Measurements and results: We demonstrated that there was a dose-dependent increase in mucin secretion by enzyme-linked lectin assay after incubation with 1.69 g/dL (597 mOsm/L), 3.69 g/dL (1,192 mOsm/L), 5.69 g/dL (1,823 mOsm/L), and 10.69 g/dL (3,612 mOsm/L) of saline solution over Krebs-Henseleit solution control (288 mOsm/L) [p < 0.01 for 1.69 g/dL of saline solution and p < 0.0001 for others]. Mannitol solution, 15 g/dL (1,040 mOsm/L), also significantly increased mucin secretion (n 4, p < 0.005). There was a 47% and 54% increase in secretion of the serous cell product lysozyme after exposure to 3.69 g/dL (1,192 mOsm/L) and 10.69 g/dL (3,612 mOsm/L) saline solutions, respectively (n 5, p < 0.05). Secretion was only stimulated when the hyperosmolar exposure was on the luminal side of the epithelium. Mucin secretion was induced within minutes of 3.69 g/dL of saline solution exposure, and this increased mucin secretion quickly peaked. The ratio of mucin to lysozyme secretion was approximately 2. This ratio appeared to be independent of the osmotic concentration of the stimulus and therefore of secretory rate. Conclusions: Mucus secretion is markedly stimulated in response to hyperosmolarity. This may be a protective response. These results also suggest that the therapeutic use of hyperosmolar aerosols should be evaluated with care when used for patients with mucus hypersecretion and impaired mucus clearance. (CHEST 2003; 124:306–313)

症例は63歳,男性.総胆管結石症のため19年前に経十二指腸乳頭括約筋形成術およびTチューブドレナージ術を受けた.逆行性胆管炎を繰り返した後,腹部超音波検査にて肝左葉に径9cmの腫瘍を認めたため入院となった.血中CA19-9は1, 272.5U/mlと上昇していた.腫瘍はCTにて不規則に造影される低吸収域として,血管造影では乏血性の腫瘍としてみられた.内視鏡的逆行性胆管造影では左側肝内胆管の狭窄像を認め,肝内胆管癌を疑い肝拡大左葉+S1切除兼胆管切除,右肝管空腸吻合術を施行した.病理診断は肝内転移を有する末梢型の中分化型胆管細胞癌であった.随伴する慢性胆管炎と肝内結石は腫瘍発生の誘因として考えられた.術後経過は良好であったが, 17カ月目に再発のため死亡した.経十二指腸乳頭括約筋形成術による乳頭機能廃絶のため招来される逆行性胆管炎は胆管癌発生との関与が指摘されており,経過観察には十分な注意を要する.

Mucus hypersecretion is an important characteristic of many airway diseases. Mucin is the major component of mucus, and is secreted from surface goblet cells of the airway epithelium and mucous cells of submucosal glands. Lysozyme is an enzyme secreted by serous cells of airway submucosal glands. We hypothesized that secretagogues acting through different pathways would have different effects on tracheal mucin and lysozyme secretion. We used a sandwich enzyme-linked lectin assay (ELLA) to measure mucin-like glycoprotein secretion and a spectrophotometric method to measure lysozyme secretion from isolated ferret tracheal segments. We evaluated the secretory response to four secretagogues; prostaglandin F(2alpha) (PGF(2alpha)), adenosine triphosphate (ATP), methacholine (MCh), and human neutrophil elastase (HNE). Each agent stimulated mucin and lysozyme secretion. The relative potency was PGF(2alpha)< or =ATP

Neutrophil-dominated inflammation is prominent in the cystic fibrosis (CF) and chronic bronchitis (CB) airways. We assessed the degree of airway inflammation by measuring the sputum concentrations of interleukin (IL)-8, myeloperoxidase (MPO), and deoxyribonucleic acid (DNA). We determined the relationship among the concentrations of these mediators and investigated methodological problems that may be responsible for reported variability in measurements. Sputa obtained from 31 patients were solubilized with phosphate-buffered saline, dithiothreitol (DTT) (0.1% or 1%), or dornase alfa (0.2 mg/mL). The sputum concentration of IL-8 and MPO was measured by enzyme-linked immunosorbent assay (ELISA), and DNA was measured using microfluorimetry. There was a significant relationship among sputum IL-8, MPO, and DNA. For MPO (means +/- SD), CF was 1,392 +/- 771 vs. CB at 75 +/- 65 mcg/mL; P < 0.0001. For IL-8: CF was 239 +/- 154 vs. CB at 121 +/- 108 ng/mL; P = 0.0002. For DNA, CF was 1.707 +/- 1.25 vs. CB at 0.184 +/- 0.272 mg/mL; P < 0.0001. The MPO concentration in CF sputum was approximately double after in vitro treatment with dornase alfa (P < 0.0001). There is a greater concentration of IL-8, MPO, and DNA in CF than in CB sputa. There is a significant relationship among these inflammatory markers in sputum. DNA polymers bind myeloperoxidase in the sputum, and we speculate that treatment with dornase alfa may remove a source of MPO inhibition.

This study was designed to examine the draining lymph node basin at highest risk of metastasis in lower rectal cancer using 99 mTc-tin colloid. In 43 patients, the area with highest hot nodes density was defined as the draining lymph node basin using a gamma probe. Metastatic states of all removed lymph nodes were examined histologically. A total of 203 hot nodes were identified in 39 patients (91 percent) with a mean of 5.2 nodes. The number of removed lymph nodes was 808 nodes: 670 nodes in the mesorectum, and 138 nodes in the pelvis. In 21 patients, the metastatic states of 119 nodes were investigated histologically. From the distribution of the identified hot nodes, the draining lymph node basins were classified into two patterns: lateral type (n = 17), and mesorectal type (n = 22). Only 20 (17 percent) of 119 positive nodes were identified as hot node. Tumor cells that occupied the lymph node diffusely or massively probably interfered with the exact diagnosis of metastasis. Lymph node metastasis in the pelvis was observed in 5 patients (13 percent). One false negative was of the mesorectal type with diffuse metastases in the para-aortic lymph nodes. The remaining four patients were of the lateral type and all positive lymph nodes, including positive nonhot nodes, were located within the draining lymph node basin. Consequently, in 20 (95.2 percent) of 21 patients with lymph node metastasis, all positive lymph nodes were located within the draining lymph node basin of the tumor. Two types of the draining lymph node basin of advanced lower rectal cancer were identified using this method. The concordance between lymph node metastases and the draining lymph node basin is good.

Secretory phospholipases A2(sPLA2) are increased in the bronchoalveolar lavage fluid of patients with asthma and acute respiratory distress syndrome. Intratracheal sPLA2instillation induces acute lung injury in the rat and guinea pig. We hypothesized that sPLA2would stimulate mucus secretion in vitro and that intratracheal sPLA2exposure would induce mucus hypersecretion and airway inflammation in the ferret trachea in vivo. In vitro, porcine pancreatic sPLA2at a concentration of 0.5 or 5 U/ml significantly increased mucous glycoconjugate (MG) secretion from the excised ferret trachea. P-bromophenacylbromide (a sPLA2inhibitor), quercetin (a lipoxygenase inhibitor), or MK-886 (a 5-lipoxygenase inhibitor), each at 10−4M, significantly reduced sPLA2-induced MG secretion. sPLA2-stimulated MG secretion was decreased in Ca2+-free medium. In vivo, ferrets were intubated for 30 min once per day for 3 days using an ETT coated with 20 units of porcine pancreatic sPLA2mixed in water-soluble jelly. Constitutive MG secretion increased 1 day after sPLA2exposure and returned to control 5 days later. Human neutrophil elastase (HNE) at 10−8M increased MG secretion in the sPLA2-exposed trachea compared with that in the control trachea, but methacholine at 10−7M did not. sPLA2-induced secretory hyperresponsiveness continued for at least 5 days after sPLA2exposure ended. sPLA2increased tracheal inflammation, MG secretion, and secretory hyperresponsiveness to HNE probably through enzymatic action rather than by activation of its receptor.

Vasoactive intestinal peptide (VIP) and nitric oxide (NO) are neurotransmitters involved in the regulation of bronchial and pulmonary vascular tone. Published studies of the effects of VIP on airway mucus secretion have yielded conflicting results. The purpose of this study was to determine the effect of VIP on mucus secretion in the ferret trachea and if this effect was influenced by NO. We used a sandwich enzyme-linked lectin assay to measure mucin secretion and a turbidimetric assay to measure lysozyme (serous cell) secretion from ferret tracheal segments. VIP (10−7 M) increased mucin secretion over 2 h. VIP (10−9 to 10−5 M) stimulated mucin secretion in a dose-dependent fashion. VIP-induced mucin secretion was partially blocked by a VIP receptor antagonist (a chimeric VIP-pituitary adenylate cyclase-activating peptide analog, VIP receptor antagonist) at a 10-fold excess concentration. At all concentrations tested, neither NG-nitro-l-arginine methyl ester, an inhibitor of NO synthase, nor S-nitroso- N-acetyl-penicillamine, an NO donor, had any significant effect on constitutive or VIP-induced mucus secretion. We conclude that VIP-stimulated mucin and lysozyme secretion was both time dependent and dose dependent and that NO neither stimulates nor inhibits mucus secretion in the ferret trachea.

Osteomas of the middle ear are rare benign neoplasms. To date, 21 cases have been reported in the English literature. They most commonly arise from the promontory, and only 2 cases of these reports describe osteomas of the ossicles, inseparable from malleus and incus, respectively. The most common symptom is conductive hearing loss because of the impingement of the ossicular chain. Some cases are asymptomatic and are diagnosed incidentally. Osteomas are slow growing, and surgical excision is recommended only for symptomatic lesions. We describe a rare case of malleus osteoma in a 13-year-old boy with conductive hearing loss. Clinical manifestations, etiologic factors, and treatment of this lesion are discussed.

One of the difficulties in assessing mucoactive therapy is selecting clinical outcome variables that reflect the impact of clearing airway secretions on quality of life (QOL). Petty and colleagues developed a questionnaire designed to evaluate the clinical impact of mucoactive therapy in patients with chronic bronchitis (CB). We evaluated this questionnaire in a multicenter study of a mucolytic medication used in patients with CB and hypothesized that spirometry, exercise capacity, and sputum clearability changes would correlate with QOL changes. This was a multicenter trial in 159 patients with stable CB (111 completed the 16-week study). Spirometry, plethysmography, the 6-minute walk test (6MWT), and Petty score as a measure of QOL were assessed at each visit. Sputum was collected at each visit. Cough transportability was measured in a cough machine, and mucociliary transportability was measured on the frog palate. Cohesivity was measured in a filancemeter, interfacial tension by de Nouy ring, and wettability by contact angle analysis. Within the entire data set of 694 evaluations, there was no correlation between pulmonary function and QOL. There was an inverse correlation with distance covered in a 6MWT (R(2) = 0.041, p < 0.0001). Sputum CTR was directly correlated with QOL (R(2) = 0.027, p < 0.0001). Change from baseline (mean of first three visits) was computed and compared the change in the mean of values at the 8- and 12-week visits (n = 108 sets of data pairs). This was analyzed as a percentage of change for continuous measurements, and as QOL is normative, we calculated the absolute change in QOL. There was no relation between QOL and 6MWT changes. There was an inverse relation between change in forced expiratory volume in 1 second and QOL (R(2) = 0.092, p = 0.0021) as well as between forced vital capacity and QOL (R(2) = 0.05, p = 0.024). There was a direct relation between CTR and QOL (R(2) = 0.039, p = 0.048). The relation between QOL and 6-minute walk distance was expected but weak. The consistent relation between CTR and QOL (suggesting that improved CTR of sputum is associated with decreased QOL) is difficult to explain. A change in forced expiratory volume in 1 second and forced vital capacity did correlate with a change in QOL. There is a need for a good QOL tool to evaluate mucus clearance devices or medications. The Petty questionnaire was designed specifically for this task, but the effect on sputum properties by current mucoactive agents may be too small to elicit a significant change in the Petty score.

Airway mucus hypersecretion is in part a response to infection and inflammation. Pseudomonas aeruginosa infection is nearly universal in advanced cystic fibrosis (CF) lung disease. Mucoid strains of P. aeruginosa produce an exopolysaccharide product called alginate. The purpose of this study was to determine whether P. aeruginosa alginate stimulates secretion from mucous or serous cells in the ferret trachea exposed to alginate at concentrations reported to be present in the CF airway. We used a sandwich enzyme-linked lectin assay (ELLA) to measure mucin secretion and spectrophotometry to measure lysozyme secretion from isolated ferret tracheal segments. Purified Pseudomonas aeruginosa alginate stimulated mucin and lysozyme secretion in a dose-dependent fashion (mucin = +111%: P = 0.003; lysozyme = +20%: P = 0.024 at 200 microg/mL). This stimulated secretion was not due to proteolytic activity, and alginate exposure did not produce ultrastructural damage to the trachea. We conclude that alginate may contribute to mucus hypersecretion and respiratory morbidity associated with P. aeruginosa infection in patients with CF.

The aim of this study is to provide a novel method for extending the field of view in lumber spine biomagnetic imaging. The extension of the field of view is achieved by combining multiple measurements using positional relationship between the sensor array and the subject’s body; the relationship is obtained using marker measurements performed together with each magnetic field measurement. Functional lumber spinal cord imaging is performed by using the spatial filter technique. We measure spinal cord evoked magnetic field from five healthy volunteers by applying 4-Hz electric stimuli at their peroneal nerve. Our proposed large field-of-view imaging shows clear nerve conduction in the lumber spine region for all five subjects, demonstrating its effectiveness.

Cryopump is one type of storage pumps and offers truly contamination free vacuum. Commercial cryopumps which are cooled by refrigerator have made remarkable development in the last ten years and become practical industrial tool, for instance, in the field of semiconductor manufacture. Cryopumps which are cooled by liquid helium have been used to pump large amount of hydrogen gas in high energy neutral beam injector of large plasma devices and their applicability to pumping system of fusion reactor which exhausts mixtures of hydrogen isotopes and helium gases is now under study.

Vacuum technology on a mirror type engineering test reactor on the model of the Tandem Mirror Technology Demonstration Facility (TDF) designed at Lawrence Livermore National Laboratory is described. The vacuum technology used in mirror type machine is remarkably different from that in torus type one.

A nitrogen cluster beam (neutral particle intensity of 28.6 mAeq) is ionized by electron collisions in a Bayard-Alpert gauge type ionizer. The extraction efficiency of about 65% is obtained at an electron current of 10 mA with an energy of 50 eV. The mean cluster size produced at a pressure of 663 Torr and temperature of 77.3 K is 2×105 molecules per cluster. By the Coulomb repulsion force, multiply ionized cluster ions are broken up into smaller fragments and the cluster ion size reduces to one-fourth at an electron current of 15 mA. Mean neutral cluster sizes depend strongly on the initial degree of saturation Φ0 and are 2×105, 7×104 and 3×104 molecules per cluster at Φ0's of 0.87, 0.66 and 0.39, respectively.

The electron density of transient plasma was measured with Michelson type CO2 laser interferometer. The stability of the CO2 laser, the directivity of the laser beam and the accuracy of the density measurement were investigated.

Spatial distributions of electron density, electron temperature and plasma potential were measured in an energetic are with rotating electrostatic probe on the condition of 1000-4000 gauss magnetic field strength, 3x10-2-3x10-5 torr argon gas pressure and 50-200 A discharge current. The density and temperature obtained at the axis of arc plasma column were about 1014 cm-3 and 2x105 K, respectively. At the pressure lower than 10-4 torr the spatial distribution of plasma potential were connected with ion Larmor radius. The density and temperature distributions were examined for the fully ionized plasma. At the higher pressure the effects of collisions between the charged particles and gas molecules on the characteristics of plasma were investigated.

For heating of plasmas by injection of hydrogen cluster ions, the specific size (N/Z)≈102 molecules/charge is believed to be most desirable. A fundamental research to develop a practical method for tailoring large cluster ions into small suitable sizes has been carried out by using nitrogen cluster ions of the initial mean specific size (N/Z¯)o≃105. The beam of neutral large clusters of total intensity 20 mAeq was led to an ionizer and then the large cluster ions are accelerated to 8.9 keV before entering the divider which disintegrates them into small fragments by multiple ionization. The mean specific size of disintegrated cluster ions (N/Z¯)′ becomes smaller with increase in ionizing electron current of the divider. (N/Z¯)′ becomes 103~104 at an electron current of 140 mA and an accelerating voltage of 680 V of the divider with its efficiency of 20~60%. Thus, the original large cluster ions are divided into small fragments of which the mean specific size is 1/20~1/100 of the initial value without much decrease in total intensity of the cluster ion beam.

Studies have been made of the problems encountered in the development of a large-sized catalytic pump for the pumping of hydrogen in nuclear fusion apparatus. An experimental pump having a speed of about 5000 liter/sec is assumed to use at partial pressures between 10-7 and 10-5 Torr. The influence of water vapor on the atomization of hydrogen at the rhenium filament is one of the problems, and is discussed from the structural point of view. The lifetime of the cuprous oxide layer is another important problem. A convenient method of oxidation of copper plates by atomic oxygen produced at an incandescent rhenium filament is proposed for the generation and regeneration of the oxide. The optimum temperatures of the cuprous oxide layer are also determined for the rapid desorption of water vapor from the oxide and for the effective reaction with hydrogen atoms.