The kinetics of the reaction of carbon dioxide with mono-and diethanolamine in such nonaqueous solvents as methanol, ethanol, and %propano1 and in water were studied using a stirred tank absorber with a plane gas-liquid interface at 303 K. The reaction was found to be of first order with respect to carbon dioxide for every solvent. The order of reaction with respect to ethanolamine was found to be unity only for an aqueous solution of monoethanolamine and for the other solutions, ranged from 1.4 to 2, depending on the solvent species. The reaction order was increased in the order of water, methanol, ethanol, and Zpropanol. The variation of the reaction order with the solvent species could be explained in terms of a reaction scheme via a zwitterion. Almost linear dependence of the logarithm of the reaction rate constant on the solubility parameter of the solvent was derived. SCOPEGas purification by chemical absorption is of great industrial importance. Alkanolamine solutions are frequently used for the removal of acid gases (Wall, 1975). Although many studies have been done toward the mechanisms and kinetics of the reaction between carbon dioxide and various amines (Blauwhoff et al., 1983), the reaction media are limited to aqueous solutions. In practice, nonaqueous systems comprising methanol solution of alkanolamine have been commercially employed for absorption of carbon dioxide, hydrogen sulfide, carbonyl sulfide, etc., because of their high solubility and capacity, their low corrosiveness, and their low energy consumption during regeneration of used liquor (Bratzler and Doerges, 1974). Nonaqueous systems, which are essentially used in a closed loop, should be considered more for acid gas removal.The reaction between carbon dioxide and monoethanolamine in aqueous solutions has already been found to be of first order with respect to both species, while for the carbon dioxidediethanolamine system in aqueous solutions, the order of reaction with respect to diethanolamine has not been determined to be of first or second order. Danckwerts (1979) and Laddha and Danckwerts (1981) proposed a new reaction mechanism comprising formation of a zwitterion followed by the removal of proton by a base (diethanolamine) to explain such contradiction of the reaction order. It would be expected that the order of reaction with respect to ethanolamine ranges from first to second order in nonaqueous solvents. The variation of the reaction order with a physicochemical property of the solvent and the resultant reaction rate constants seem to be of practical interest.In the present work, the kinetics of the reaction of carbon dioxide with mono-and diethanolamine in such nonaqueous solvents as methanol, ethanol, and Z-propanol were investigated using a stirred tank absorber with a plane gas-liquid interface. The absorption rate data under the fast reaction regime were analyzed in terms of the reaction mechanism proposed by Danckwerts (1979). An attempt was made to correlate the derived reaction rate constants in different nonaqueous s...

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Background The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), began in late 2019. One of the vaccines approved against COVID-19 is the BNT162b2 mRNA COVID-19 vaccine (Pfizer/BioNTech). Case presentation We present the case of a 71-year-old man with no history of the SARS-CoV-2 infection or any recent viral or bacterial illnesses who presented with bilateral oculomotor palsy and limb ataxia after BNT162b2 mRNA COVID-19 vaccination. The diagnosis of Miller Fisher syndrome (MFS) was established based on physical examination, brain magnetic resonance imaging (MRI), cerebrospinal fluid analysis (CSF), and positron emission tomography (PET). There was no evidence of other predisposing infectious or autoimmune factors, and the period from COVID-19 vaccination to the appearance of neurological symptoms was similar to that of other vaccines and preceding events, such as infection. Conclusion Guillain–Barré syndrome (GBS) and its variants after COVID-19 vaccination are extremely rare. Note that more research is needed to establish an association between MFS and COVID-19 vaccines. In our opinion, the benefits of COVID-19 vaccination largely outweigh its risks.

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Background and Purpose— Cortical microinfarcts (CMIs) are small ischemic lesions found in cerebral amyloid angiopathy (CAA) and embolic stroke. This study aimed to differentiate CMIs caused by CAA from those caused by microembolisms, using 3-Tesla magnetic resonance imaging. Methods— We retrospectively investigated 70 patients with at least 1 cortical infarct <10 mm on 3-dimensional double inversion recovery imaging. Of the 70 patients, 43 had an embolic stroke history (Emboli-G) while 27 had CAA-group. We compared the size, number, location, and distribution of CMIs between groups and designed a radiological score for differentiation based on the comparisons. Results— CAA-group showed significantly more lesions <5 mm, which were restricted to the cortex ( P <0.01). Cortical lesion number was significantly higher in Emboli-G than in CAA-group (4 versus 2; P <0.01). Lesions in CAA-group and Emboli-G were disproportionately located in the occipital lobe ( P <0.01) and frontal or parietal lobe ( P =0.04), respectively. In radiological scoring, ≥3 points strongly predicted microembolism (sensitivity, 63%; specificity, 92%) or CAA (sensitivity, 63%; specificity, 91%). The areas under the receiver operating characteristic curve were 0.85 and 0.87 for microembolism and CAA, respectively. Conclusions— Characteristics of CMIs on 3T-magnetic resonance imaging may differentiate CMIs due to CAA from those due to microembolisms.

ObjectivesCerebral microbleeds (CMBs) are often observed in memory clinic patients. It has been generally accepted that deep CMBs (D‐CMBs) result from hypertensive vasculopathy (HV), whereas strictly lobar CMBs (SL‐CMBs) result from cerebral amyloid angiopathy (CAA) which frequently coexists with Alzheimer's disease (AD). Mixed CMBs (M‐CMBs) have been partially attributed to HV and also partially attributed to CAA. The aim of this study was to elucidate the differences between SL‐CMBs and M‐CMBs in terms of clinical features and regional distribution.MaterialsWe examined 176 sequential patients in our memory clinic for clinical features and CMB location using susceptibility‐weighted images obtained on a 3T‐MRI. The number of lobar CMBs in SL‐CMBs and M‐CMBs was counted in each cerebral lobe and their regional density was adjusted according to the volume of each lobe.ResultsOf the total 176 patients, 111 patients (63.1%) had CMBs. Within the patients who had CMBs, M‐CMBs were found in 54 patients (48.6%), followed by SL‐CMBs in 35 (31.5%) and D‐CMBs in 19 (17.1%). The SL‐CMB group showed a significantly higher prevalence of family history of dementia, whereas the M‐CMB group showed an increasing trend toward hypertension and smoking. The prevalence of AD was significantly higher in the SL‐CMBs group, whereas the prevalence of AD with cerebrovascular disease was higher in the M‐CMBs group. The regional density of lobar CMBs was significantly higher in the occipital lobe in the M‐CMB group, whereas the SL‐CMB group showed higher regional density between regions an increasing tendency in the parietal and occipital lobe.ConclusionThe between‐group differences in clinical features and regional distribution indicate there to be an etiological relationship of SL‐CMBs to AD and CAA, and M‐CMBs to both HV and CAA.