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No comprehensive analysis of the pulmonary sequelae of coronavirus disease 2019 (COVID-19) in Japan based on respiratory function tests and chest computed tomography (CT) has been reported. We evaluated post-COVID-19 conditions, especially focusing on pulmonary sequelae assessed by pulmonary function tests and chest CT.

The nasal mucosa functions as a frontline biological defense against various foreign substances and pathogens. Maintaining homeostasis of the nasal epithelium is necessary to promote good health. Nasal epithelia are constantly replaced under normal conditions. However, hereditary diseases, including primary ciliary dyskinesia and cystic fibrosis, can result in intractable dysfunction of the nasal mucosa. Since there is no treatment for this underlying condition, extrinsic manipulation is necessary to recover and maintain nasal epithelia in cases of hereditary diseases. In this study, we explored the use of airway epithelial cells (AECs), including multiciliated airway cells, derived from human induced pluripotent stem cells (iPSCs) on porcine atelocollagen vitrigel membranes, as a candidate of a therapeutic method for irreversible nasal epithelial disorders. To confirm the regenerative capacity of iPSC-derived AECs, we transplanted them into nasal cavities of nude rats. Although the transplanted cells were found within cysts isolated from the recipient nasal respiratory epithelia, they survived in some rats. Furthermore, the surviving cells were composed of multiple cell types similar to the human airway epithelia. The results could contribute to the development of novel transplantation-related technologies for the treatment of severe irreversible nasal epithelial disorders.Impact StatementNasal respiratory epithelia are important for the functions of nasal cavity, including humidifying the air and filtering various toxic substances. However, hereditary diseases, including primary ciliary dyskinesia and cystic fibrosis, can result in intractable dysfunction of the nasal mucosa. Our novel method to transplant airway epithelial cells derived from human induced pluripotent stem cells will be a candidate method to replace malfunctioned nasal respiratory epithelia in such a situation. To secure our method's safety, we used porcine atelocollagen vitrigel membranes, which prevent the immune response and bovine spongiform encephalopathy, as a scaffold.

Background Strong eosinophil infiltration in chronic rhinosinusitis with nasal polyp (CRSwNP) is highly associated with recalcitrance and higher nasal polyp recurrence rate after surgery. The prevalence of eosinophilic CRSwNP (ECRS) is increasing in Asian countries including Japan. Benralizumab is a humanized anti-IL-5R alpha monoclonal antibody that depletes eosinophils by antibody-dependent cell-mediated cytotoxicity.Objective To assess the efficacy and safety of benralizumab in patients with ECRS.Methods This phase II, randomized, double-blind, placebo-controlled study was conducted in Japan. Patients were randomized 1:2:2 to placebo, a single administration of benralizumab 30 mg, or benralizumab 30 mg every 4 weeks (q4w) for a total of three doses. The primary endpoint was the change in nasal polyp score from baseline at Week 12.Results Overall, 56 patients were enrolled (placebo, n?=?11; benralizumab single dose, n?=?22; benralizumab q4w, n?=?23). Although the mean total nasal polyp score began to decrease after the initiation of benralizumab treatment, there were no statistically significant differences in change in nasal polyp score from baseline at Week 12 between benralizumab and placebo (placebo, -0.5?±?0.8; benralizumab single, -0.3?±?0.8; benralizumab q4w, -0.5?±?1.5). Post-hoc analysis showed that the administration of benralizumab decreased nasal polyp scores =2 points in 42.2% of ECRS patients and that patients with high blood eosinophil levels had a greater tendency to respond to benralizumab treatment. The safety profile was similar to that in previous studies and no unexpected adverse events were noted.Conclusion Although benralizumab did not meet the primary efficacy endpoint, reductions of nasal polyp scores were seen in the benralizumab group compared with the placebo group over the whole study period, especially in patients with high levels of blood eosinophils.

A venous aneurysm is a relatively rare disease defined by cystic vasodilated lesions in a general vein. Popliteal venous aneurysm (PVA) is a rare clinical entity, and the first signs may be a thromboembolic event. They can cause potentially life-threatening diseases, such as pulmonary embolism and deep venous thrombosis. A left-sided inferior vena cava (IVC) is a common anomaly associated with venous thrombus, resulting in anatomical variations in the venous return from the lower limbs. The general vascular malformation of PVA and left-sided IVC should also be preoperatively understood because of the unpredictable risk of thromboembolic complications.

Abdominal aortic aneurysm diameter is usually measured by the maximum minor-axis diameter on axial computed tomography (CT). However, this “traditional” diameter may underestimate the real size, as the aorta is not always straight and the aneurysm shape is sometimes in the form of an ellipse along the cross section. Therefore, we measured maximum major-axis diameters using a three-dimensional (3D) workstation and compared them with the traditional maximum minor-axis diameters measured using thin-slice axial CT.

Poor connectivity is common when we use wireless networks on the go. A natural way to tackle the problem is to take advantage of the multiple network interfaces on our mobile devices, and use all the networks around us. Using multiple networks at a time makes makes possible faster connections, seamless connectivity and potentially lower usage charges. The goal of this paper is to explore how to make use of all the networks with today's technology. Specifically, we prototyped a solution on an Android phone. Using our prototype, we demonstrate the benefits (and difficulties) of using multiple networks at the same time.

We present a case of a left subclavian artery aneurysm in a 48-year-old man with Marfan syndrome. Aneurysms of the subclavian artery are rare in patients with Marfan syndrome. Resection of the aneurysm and interposition with a synthetic graft were performed through a supra- and infraclavicular incision, without resecting the clavicle. Histological findings were compatible with Marfan syndrome. In patients with Marfan syndrome, regular follow-up is important because of the occurrence of peripheral aneurysms other than the aorta.

Background The University of Pennsylvania Smell Identification Test (UPSIT) is a popular olfactory function test used throughout the world. In Japan, however, it is not widely used because it is written in English and some of the test odorants are unfamiliar to the Japanese population. Recently, a cross-culturally modified UPSIT was developed. This study was designed to determine if the Japanese version of the UPSIT (UPSIT-J) is effective in Japanese populations.Methods We administered the UPSIT-J to 50 normosmic Japanese subjects and 54 Japanese patients with known olfactory dysfunction. Subjects were also administered the Japanese standard olfactory threshold test (T&T olfactometry), the Odor Stick Identification Test for Japanese (OSIT-J) and i.v. olfactometry (the Alinamin test). Test results from the UPSIT-J and subjects’ opinions were compared with the standard Japanese tests of olfactory function.Results Most subjects reported that the UPSIT-J was easy and interesting compared with OSIT-J and easier and more interesting than the T&T olfactometry and Alinamin test. Identification rates for nine of the UPSIT-J odorants were found to be<80% for normal subjects. UPSIT-J scores correlated with subjects’ self-reported levels of olfactory function (rs= 0.85), OSIT-J score (rs= 0.86), recognition threshold of the T&T olfactometry (rs= 0.80), and Alinamin test results (rs= 0.38 for latency; rs= 0.52 for duration time).Conclusion Although a cultural bias was detected for some test odorants, this study indicates that the UPSIT-J is effective for use in the clinic to assess olfactory function in the Japanese population.

Patients with obstructive sleep apnea (OSA) have an increased risk of cardiovascular morbidity. This study aimed to determine circulating carbon monoxide (CO) levels, which have been suggested to be a marker of cardiovascular risk in patients with OSA.

OBJECTIVE To investigate whether a new clinical olfactory test, the Odor Stick Identification Test for Japanese (OSIT-J), can be used to assess olfactory function cross-culturally in a US patient population. DESIGN Cross-sectional prospective study. SETTING A university medical center otolaryngology clinic. PATIENTS Fifty US patients presenting with complaints of olfactory dysfunction from December 2004 to January 2006. INTERVENTIONS Olfactory testing and patient interview. MAIN OUTCOME MEASURES Comparison of test results obtained with the OSIT-J, the Connecticut Chemosensory Clinical Research Center (CCCRC) olfactory function test, and patients' self-reported level of olfactory function. Patients' opinions regarding the 2 test methods were also recorded. RESULTS The mean ± SD time required to administer the OSIT-J (8 ± 1 minutes) was shorter than that required for the standard CCCRC test (21 ± 6 minutes). Significant Spearman rank correlations were found between the OSIT-J and CCCRC test scores (rs = 0.80, P&lt;.001, n = 50), and patients' self-reported level of olfactory function (rs = 0.73, P&lt;.001, n = 50). Although 3 of the 13 odors used in the OSIT-J were not familiar to US subjects, patients reported that the OSIT-J was easier, more interesting, and the odors used more pleasant than the CCCRC test. CONCLUSIONS Olfactory function tests developed in different countries should be evaluated to determine if a cross-cultural bias exists among test odorants. Although a cultural bias was detected for a few odorants, this study demonstrates that a modified version of the OSIT-J can be used to assess olfactory function in US patients.Arch Otolaryngol Head Neck Surg. 2007;133:331-336--

Matrix metalloproteinases function in the remodeling of the extracellular matrix during growth and development as well as in injury and disease processes. We examined the role of matrix metalloproteinase-9 in a model of olfactory nerve injury in mice. We measured changes in matrix metalloproteinase-9 protein levels for up to 60 days following olfactory nerve transection. Matrix metalloproteinase-9 levels increased within hours after injury, peaked at day 1 and were elevated for approximately 2 weeks before returning to control levels over the 60-day time period. The increase in matrix metalloproteinase-9 was temporally associated with the degeneration of olfactory neurons that follows nerve transection and with increased gliosis. Our results demonstrate a temporal relationship between matrix metalloproteinase-9 elevation, degeneration of olfactory neurons and gliosis.

Abstract. Bioabsorbable and functionally graded apatites (fg-HAp) ceramics were designed using calcined bovine bone (b-HAp) by the partial dissolution-precipitation methods. The fg-HAp ceramics with micro-pores of 10-160 nm had larger specific surface areas (30-40 m2･g-1) than the b-HAp ceramics, although the two HAp ceramics exhibited same macro-pore sizes of 100-600 µm and porosities of 60-80 %. Surface structure of these ceramics was modified by soaking at 309.5 K for 1-90 days in a simulated body fluid (SBF). At 8 days after the soaking, microstructure of the fg-HAp changed from small grains to dense cocoon-like ones by rapid precipitation of HAp microcrystals, while at 14 days, that of the b-HAp was porous urchin-like grains, suggesting that the fg-HAp had higher bone-bonding ability than the b-HAp.

We performed 167 femoropopliteal bypass surgeries in 151 patients (95 patients underwent above-knee bypass and 56 below-knee bypass) from December 1985 to December 2000 with the use of prosthetic graft or autologous vein graft. We compared primary patency rates between age, sex, graft material, distal anastomotic site and severity of ischemia, considering their survival rates to elucidate the long-term outcome of above-knee and below-knee femoropopliteal bypass. The 10 year patency rate for above-knee bypass was 47.4%, compared to 36.9% for below-knee (p< 0.01). Better results were found after bypass surgery for claudicants than for critical ischemia (p< 0.05). With regard to graft material and age categories, there were unexpectedly no statistical differences in either above-knee or below-knee anastomosis. The survival rate at 10 years in claudicants was 51.2%, compared to 15.9% with critical ischemia (p< 0.01). Mortality was much influenced by ischemic heart disease (p< 0.002) and the age of patient (p< 0.05). The results after above-knee bypass had comparable patency, whereas the results after below-knee bypass were disappointing. Below-knee arterial reconstruction for claudicants should be carefully considered and might be recommended only to patients with critical ischemia.

The Freeze-Purged-Desorption (FPD) method was developed for the experimental measurement of gas permeability coefficients as a new technique using a desorption curve of gas immobilized in polymeric films. The FPD method was effectively used to evaluate four gas permeation parameters (CD, CH, DD, and DH) of glassy polymeric films (polycarbonate and polystyrene) by using CO2. The modes of the CO2 gas desorption response curve (D-curve) obtained were sensitively characterized by the proportion of sorption in the Henry and Langmuir modes in the polymeric films accompanied by their own gas diffusivity. A graphical analysis of the D-curve of CO2 reasonably proposed a linear relation between the desorption rate and the sorption amount of CO2, which was strongly influenced by the kind of sorption gas, film, temperature, and other factors. The desorption rate of sorbed CO2 gas for the PC and PS films gave a characteristic straight line with an inflection point indicating a shift in the gas-diffusion mechanism from the complex type of the Henry and the Langmuir modes to the Langmuir mode. The characteristic D-curves obtained were graphically analyzed, and they clearly discriminated the Henry mode part and the Langmuir mode part. This discrimination process quantitatively and individually evaluated CD, CH, DD, and DH. By using the four parameters evaluated, a mathematical model to describe the D-curve was proposed, and it consistently explained the experimental D-curves. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 934–941, 2004

We investigated whether fibrin glue (FG) might be useful as a carrier of amikacin (AMK) for prevention of local graft infection. After AMK (4.0mg)-treated FG (AMK-FG) polyurethane grafts were implanted subcutaneously in the anterior abdominal region of Sprague-Dawley rats, AMK concentrations in tissues surrounding the implantation sites were compared over time with concentrations at the same sites in rats given an intravenous injection of AMK (4.0mg). In the injection group, AMK concentrations in serum were detectable only for 4h, whereas AMK released from AMK-FG grafts remained detectable over 24h. Until 4h after implantation, AMK concentrations in tissues near implantation sites were significantly higher in the AMK-FG graft group than in the injection group; peak local concentrations during that time were 210 times higher for the AMK-FG graft group than for the injection group. Areas under the tissue concentration–time curve (AUC) for AMK were 171µg·h/g and 1.35µg·h/g in the AMK-FG graft and injection groups, respectively. FG therefore was considered to control release of AMK and to maintain a high AMK concentration in tissues surrounding the implantation site. Thus, AMK-FG polyurethane graft delivery may be useful in preventing local infection by local delivery of AMK.

We investigated whether fibrin glue (FG) might be useful as a carrier of amikacin (AMK) for prevention of local graft infection. After AMK (4.0mg)-treated FG (AMK-FG) polyurethane grafts were implanted subcutaneously in the anterior abdominal region of Sprague-Dawley rats, AMK concentrations in tissues surrounding the implantation sites were compared over time with concentrations at the same sites in rats given an intravenous injection of AMK (4.0mg). In the injection group, AMK concentrations in serum were detectable only for 4h, whereas AMK released from AMK-FG grafts remained detectable over 24h. Until 4h after implantation, AMK concentrations in tissues near implantation sites were significantly higher in the AMK-FG graft group than in the injection group; peak local concentrations during that time were 210 times higher for the AMK-FG graft group than for the injection group. Areas under the tissue concentration–time curve (AUC) for AMK were 171μg·h/g and 1.35μg·h/g in the AMK-FG graft and injection groups, respectively. FG therefore was considered to control release of AMK and to maintain a high AMK concentration in tissues surrounding the implantation site. Thus, AMK-FG polyurethane graft delivery may be useful in preventing local infection by local delivery of AMK.

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For treatment of deep vein thrombosis and prevention of pulmonary thromboembolism, a retrievable inferior vena cava filter is commonly utilized as an effective bridge to anticoagulation. However, we have experienced difficulties in retrieving inferior vena cava filters. Endovascular retrieval assisted by disposable biopsy forceps is an appropriate approach because it provides a less-invasive low-cost way to remove a migrated filter. We suggest this troubleshooting technique to deal with filter hook migration into the caval wall.

Purpose:The diagnosis of Buerger's disease has depended on clinical symptoms and angiographic findings, whereas pathologic findings are considered to be of secondary importance. Arteries from patients with Buerger's tissue were analyzed histologically, including immunophenotyping of the infiltrating cells, to elucidate the nature of Buerger's disease as a vasculitis. Methods:Thirty-three specimens from nine patients, in whom Buerger's disease was diagnosed on the basis of our clinical and angiographic criteria between 1980 and 1995 at Nagoya University Hospital, were studied. Immunohistochemical studies were performed on paraffin-embedded tissue with a labeled streptoavidin-biotin method. Results:The general architecture of vessel walls was well preserved regardless of the stage of disease, and cell infiltration was observed mainly in the thrombus and the intima. Among infiltrating cells, CD3+T cells greatly outnumbered CD20+B cells. CD68+macrophages or S-100+dendritic cells were detected, especially in the intima during acute and subacute stages. All cases except one showed infiltration by the human leukocyte antigen-D region (HLA-DR) antigen-bearing macrophages and dendritic cells in the intima. Immunoglobulins G, A, and M (IgG, IgA, IgM) and complement factors 3d and 4c (C3d, C4c) were deposited along the internal elastic lamina. Conclusion:Buerger's disease is strictly an endarteritis that is introduced by T-cell mediated cellular immunity and by B-cell mediated humoral immunity associated with activation of macrophages or dendritic cells in the intima. (J Vasc Surg 1999;29:451-8.)

We reported recently that hypoxia inhibits baroreflex vagal bradycardia (BVB) in rats and that this inhibition persists following chemoreceptor denervation. However, since it is possible that hypoxia also affects the central processing of chemoreceptive input, the existence of chemoreceptor-mediated inhibition of BVB cannot be ruled out. Therefore, we have studied whether selective chemoreceptor activation affects BVB in normoxic conditions. In pentobarbital-urethane-anaesthetized, succinylcholine-immobilized, artificially ventilated rats, BVB was provoked by electrical stimulation of the aortic depressor nerve. Arterial chemoreceptors were selectively activated by intracarotid injection of a minute amount of sodium cyanide. Cyanide injection consistently increased blood pressure while changing heart rate variably. BVB was inhibited in a dose-dependent manner. This inhibition, as well as changes in blood pressure and heart rate, was abolished following transection of the carotid sinus nerve (CSN) ipsilateral to the injection. Spinal cord transection at the C2 level did not affect the inhibition. On the other hand, intracarotid cyanide had no effect on bradycardia elicited by electrical stimulation of a peripheral cut end of the cervical vagus nerve. We conclude that chemoreceptor activation definitely inhibits BVB and that this inhibition is mediated by the CSN, and predominantly occurs in the central nervous system. The possibility is suggested that severe hypoxia suppresses not only BVB but also the chemoreceptor-mediated inhibition of BVB, both via the direct, central action.

We reported recently that hypoxia inhibits baroreflex vagal bradycardia (BVB) in rats and that this inhibition persists following chemoreceptor denervation. However, since it is possible that hypoxia also affects the central processing of chemoreceptive input, the existence of chemoreceptor‐mediated inhibition of BVB cannot be ruled out. Therefore, we have studied whether selective chemoreceptor activation affects BVB in normoxic conditions. In pentobarbital‐urethane‐anaesthetized, succinylcholine‐immobilized, artificially ventilated rats, BVB was provoked by electrical stimulation of the aortic depressor nerve. Arterial chemoreceptors were selectively activated by intracarotid injection of a minute amount of sodium cyanide. Cyanide injection consistently increased blood pressure while changing heart rate variably. BVB was inhibited in a dose‐dependent manner. This inhibition, as well as changes in blood pressure and heart rate, was abolished following transection of the carotid sinus nerve (CSN) ipsilateral to the injection. Spinal cord transection at the C2 level did not affect the inhibition. On the other hand, intracarotid cyanide had no effect on bradycardia elicited by electrical stimulation of a peripheral cut end of the cervical vagus nerve. We conclude that chemoreceptor activation definitely inhibits BVB and that this inhibition is mediated by the CSN, and predominantly occurs in the central nervous system. The possibility is suggested that severe hypoxia suppresses not only BVB but also the chemoreceptor‐mediated inhibition of BVB, both via the direct, central action.

The short range order structure of amorphous boron is studied. Three sample materials of different appearances, film, whisker and fibre, are prepared by chemical vapour deposition by the reduction of BCl3 with hydrogen. The reduced radial distribution functions (reduced RDFs) derived from their X-ray or electron diffraction patterns are found to be almost identical among the three samples. The reduced RDFs are compared with those calculated for the four crystalline modifications of boron, i.e.a-rhombohedral,a-tetragonal,ß-tetragonal andß-rhombohedral boron. The reduced RDFs of amorphous boron are found to be similar to those of theß-tetragonal andß-rhombohedral boron. From the similarity of physical and chemical properties and co-existence in deposition, the short range order structure of amorphous boron is shown to be closer to that of theß-rhombohedral modification.

Carbon monoxide adsorbed on MgO is strongly trapped by the adsorbed carbon dioxide, increasing the heat of adsorption from 85.4 to 184.1 kJ/mol. The trapped CO is thought to be captured by two or three adsorbed CO2 and becomes less active to react with oxygen.

Short-range order (SRO) structures of various grades of amorphous boron show similar undulations on their reduced radial distribution functions (G(r)obss). The profiles of these undulations resemble those derived from the structure models ofβ-rhombohedral boron,β-tetragonal boron, and a giant cluster made up of 13 B12units. From this examination, the interconnected B48–(Td) unit, which is a main substructure of all the structure models mentioned above, seemed to be responsible for the similar undulations. In this work, however, structure simulation of amorphous boron was made solely with the B12icosahedron. Two series of boron cluster models were considered based on the difference in their bonding state through pseudo-fivefold axes, i.e., “in-phase” without rotation and “out-of-phase” differing by ∼π/5. TheG(r)calcs were calculated by means of the Fourier integral of the interference intensity functions wherein the scattering intensities were derived through a partly modified Debye's scattering intensity equation. From the comparison of the SRO structures of the cluster models to those for amorphous boron, it is indicated that the number and the bonding state of the icosahedra which constitute the boron cluster should be greater than 9–13 and should be in out-of-phase state for better correspondence.

The ratios of the amounts (R): qCO/(qCO+qCO2) from the TPD (temperature-programmed desorption) profiles of CO-derived species on MgO depend on the starting materials and the pretreatment atmospheres, which was attributed to the difference of the degree of coordinative unsaturation of each surface.

A new parameter, (Δ v)−1 is proposed for evaluating the surface basicity of alkali metal-doped MgO from a positive correlation with acetone/propene ratio in the decomposition of 2-propanol.

The possibility of designing the rate efficiency for the multi-pathway reactions of carbon monoxide oxidation on zinc oxide has been comparatively demonstrated using steady state and cyclic operations.

Stable intermediates are formed during both CO and CO2 hydrogenations on Rh/MgO at 190-220°C. The intermediates consist of at least four species, each of which is consecutively and irreversibly converted at a similar rate, forming the final product of CH4 by reaction with H2

Crystals of icosahedral B12compounds grown from high-temperature A1 solutions have been studied. The crystals grown are A1LiB14, A1MgB14and A1~1.1Be~0.6B22. They are obtained as platelets or irregularly shaped polyhedra with maximum dimensions of 5 to 7 mm. The crystallography and the mechanical properties of these materials are presented.

It is known that arterial baroreflexes are suppressed in stressful conditions. The present study was designed to determine whether and how hypoxia affects arterial baroreflexes, especially the heart rate component, baroreflex vagal bradycardia. In chloralose‐urethane‐anaesthetized rats, baroreflex vagal bradycardia was evoked by electrical stimulation of the aortic depressor nerve, and the effect of 15 s inhalation of hypoxic gas (4% O2) was studied. Inhalation of hypoxic gas was found to inhibit baroreflex vagal bradycardia. The inhibition persisted after bilateral transection of the carotid sinus nerve. Cervical vagus nerves were cut bilaterally and their peripheral cut ends were stimulated to provoke vagal bradycardia of peripheral origin so as to determine whether hypoxia could inhibit vagal bradycardia by acting on a peripheral site. In contrast to baroreflex vagal bradycardia, the vagus‐induced bradycardia was not affected by hypoxic gas inhalation. It is concluded that baroreflex vagal bradycardia is inhibited by hypoxia and the inhibition is largely mediated by its direct central action.

Since 1973 we have performed extended thymectomy for myasthenia gravis because of the presence of thymic tissue in the anterior mediastinal fatty tissue. Follow-up results were reviewed and influencing factors were investigated.

Stable intermediates are formed during the total oxidation of propene on Pt/SiO2 by nitrous oxide at 290-320°C. The surface coverage of the intermediates is 0.75(±0.08) without depending on the particle sizes of Pt. The intermediates consist of at least four species, each of which is consecutively and irreversibly converted at similar rate constant, forming the final product of propane by reaction with H2.

The active species for ethylene hydroformylation formed in the Y zeolite are extremely stable under the reaction conditions and the steady activity lasts more than one month. The catalytic activity is remarkably affected by the pretreatment of the catalyst; the He–H2pretreatment at 338–453 K enhances the activity while the He–CO or He–CO–C2H4pretreatment at 400 K reduces it.

Ethylene hydroformylation over a Nafion-supported rhodium catalyst has been studied under atmospheric pressure in the temperature range of 100–135 °C, using the transient response method.

The mode of transient response curves in CO oxidation on ZnO is drastically changed to a false start, an overshoot or an instantaneous mode, depending on the concentration region of CO. These characteristic modes and the anomalous steady state rate data which show maximum and minimum are consistently explained by the two reaction pathways model.

The oxidation of propene by nitrous oxide has been studied in detail on Pt/SiO2 of widely varying dispersion (Dh) at 160–350°C, using a tubular flow reactor under atmospheric pressure. The partial and total oxidations proceeded in parallel on two different active sites and the catalytic oscillation appeared only in the partial oxidation to form propanal (PA). For the total oxidation route, it was elucidated that the reaction was exact structure insensitive with an activation energy of 85 ± 5kJ/mol through all Dh's and that there were stable surface intermediates consisting of four different species each of which could produce CO2 and H2O by the reaction with N2O or produce propane by the consecutive reaction with H2. The turnover frequency, amplitude, period and selectivity of the oscillating PA were significantly varied depending on the percentage of platinum surface exposed, clearly indicating a strong structure-sensitive oscillation. As a possible trigger for the oscillations, the surface coverage fluctuation of weakly adsorbed propene was a reasonable choice because of its actual oscillatory behavior from θ=0.07 to 0.28 which was synchronized with the responses of the oscillatory reaction. The reaction pathway selectivity to form PA was found to be 89% for the catalyst with Dh = 80% indicating a better catalyst which can be designed by changing Dh.

An optimal proportion of multi-pathways in heterogeneous catalysis has been designed by the transient response method, as a possible model reaction, using carbon monoxide oxidation on differently prepared zinc oxides, on which two different reaction pathways occur in parallel. Two polycrystalline ZnO samples have been studied: one prepared by the New Jersey Zinc Co. (K25-ZnO) and the other by Kanto Chemical Co. (Kan-ZnO). The turnover frequency (TOF) calculated from the apparent steady state rate (SSR) on K25-ZnO (dual reaction path mechanism with L-H and E-R) is 20–370 times larger than one on Kan-ZnO (dual E-R path mechanism) at 150°C. The instantaneous TOF (transient state rate = TSR) evaluated from the transient response curves on K25-ZnO is 1.0–1.5 times higher than the steady state TOF at 150°C. The yield of CO2 produced due to the cyclic operation of the proposed PCO-jump is 31% higher than ones due to steady state operation. The computer simulation analysis concludes that the optimal reaction path proportion is 95.3% for the L-H path and 4.7% for the E-R path at SSR, and 61% for the L-H path and 39% for the E-R path at TSR, which can be designed by choosing gas compositions and operating procedures.

The adsorption behavior of carbon monoxide and carbon dioxide on oxidized and reduced surface of a-Cr2O3catalyst was studied experimentally by the application of a transient response method. From the analysis of response curves obtained for the concentration of effluent gas component and for the electrical conductivity of catalysts, it was shown that neither carbon monoxide nor carbon dioxide can be adsorbed on the oxidized surface, but they are adsorbed on the reduced surface without electron transfer between adsorbates and the catalysts. Adsorption of carbon monoxide is almost reversible, but that of carbon dioxide is both reversible and irreversible. Oxygen markedly accelerates the desorption of both carbon monoxide and carbon dioxide. It is concluded that this can be attributed to the effect of adsorbed oxygen in lowering the degree of coordinative unsaturation of Cr3+ions.