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In this study, various diamine monomers were used to synthesize aramid polymer films via a low-temperature solution condensation reaction with diacid chloride. For diamines with relatively high basicity, the reaction system became opaque because amine salt formation inhibited polymer synthesis. Meanwhile, low-basicity diamines with strong electron-withdrawing groups, such as CF3 and sulfone, were smoothly polymerized without amine salt formation to provide highly viscous solutions. The acid byproduct HCl generated during polymerization was removed by adding propylene oxide to the reaction vessel and converting the acid into highly volatile inert substances. The resulting solutions were used as varnishes without any additional purification, and polymer films with an excellent appearance were easily obtained through a conventional casting and convection drying process. The films neither tore nor broke when pulled or bent by hand; furthermore, even when heated up to 400 °C, they did not decompose or melt. Moreover, polymers prepared from 2,2-bis(trifluoromethyl)benzidine (TFMB) and bis(4-aminophenyl)sulfone (pAPS) did not exhibit glass transition until decomposition. The prepared polymer films showed a high elastic modulus of more than 4.1 GPa and a high tensile strength of more than 52 MPa. In particular, TFMB-, pAPS-, and 2,2-bis(4-aminophenyl)hexafluoropropane-based polymer films were colorless and transparent, with very high light transmittances of 95%, 96%, and 91%, respectively, at 420 nm and low yellow indexes of 2.4, 1.9, and 4.3, respectively.

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The Sonogashira coupling reaction was used to synthesize a fluorenone derivative, with an extended conjugated structure to which fluorene is connected via acetylene linkage. This compound exhibited diverse fluorescence (FL) colors in the visible region depending on the polarity of the matrix solvents used. The solvatochromic FL presented as sky blue, green, and yellow in hexane, THF, and DMF, respectively. Fluorene moiety and fluorenone moiety acted as an electron donor (D) and as an electron acceptor (A), respectively, leading to an excited state intramolecular charge transfer based on the D-π-A electronic structure. In particular, this derivative showed a remarkable FL quenching in alcohol and chloroform, probably due to vibronic coupling through hydrogen bonding with these solvents. This idea was supported by the fact that the two solvents are characterized by very high hydrogen bond donor acidities compared to other solvents used in this study. This derivative also responded to the presence of very small amounts of water at several mg/mL levels in organic solvents, resulting in remarkable FL quenching.

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Countless endeavors have been undertaken to address the Byzantine Generals Problem, a generalization of the Two Generals Problem. The emergence of proof of work (PoW) for Bitcoin has led to various consensus algorithms diverging, and comparable existing consensus algorithms are being gradually utilized interchangeably, or only developed for each specific application domain. Our approach employs an evolutionary phylogeny method to classify blockchain consensus algorithms based on their historical development and current usage. To demonstrate the relatedness and lineage of distinct algorithms, as well as to support the recapitulation theory, which posits that the evolutionary history of its mainnets is mirrored in the development of an individual consensus algorithm, we present a taxonomy. We have created a comprehensive classification of past and present consensus algorithms that serves to organize this swift consensus algorithm evolution period. By recognizing similarities, we have compiled a list of different verified consensus algorithms and performed clustering on over 38 of these. Our new taxonomic tree presents five taxonomic ranks, including the evolutionary process and decision-making method, as a technique for analyzing correlation. Through the examination of the evolution and utilization of these algorithms, we have developed a systematic and hierarchical taxonomy that enables the grouping of consensus algorithms into distinct categories. The proposed method classifies various consensus algorithms according to taxonomic ranks and aims to reveal the direction of research on the application of blockchain consensus algorithms for each domain.

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Conjugated polyelectrolytes (CPEs) are emerging as promising materials in the sensor field because they enable high-sensitivity detection of various substances in aqueous media. However, most CPE-based sensors have serious problems in real-world application because the sensor system is operated only when the CPE is dissolved in aqueous media. Here, the fabrication and performance of a water-swellable (WS) CPE-based sensor driven in the solid state are demonstrated. The WS CPE films are prepared by immersing a water-soluble CPE film in cationic surfactants of different alkyl chain lengths in a chloroform solution. The prepared film exhibits rapid, limited water swellability despite the absence of chemical crosslinking. The water swellability of the film enables the highly sensitive and selective detection of Cu2+ in water. The fluorescence quenching constant and the detection limit of the film are 7.24 × 106 L mol-1 and 4.38 nM (0.278 ppb), respectively. Moreover, the film is reusable via a facile treatment. Furthermore, various fluorescent patterns introduced by different surfactants are successfully fabricated by a simple stamping method. By integrating the patterns, Cu2+ detection in a wide concentration range (nM-mM) can be achieved.

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Vitamin B12 (B12) is involved as a cofactor in the synthesis of myelin. A lack of B12 impairs peripheral nerve production, which can contribute to sarcopenia. In this cross-sectional study, we aimed to investigate the relationship between B12 insufficiency and sarcopenia in community-dwelling older Korean adults. A total of 2325 (1112 men; 1213 women) adults aged 70-84 years were recruited. The tools used for sarcopenia were based on the Asian Working Group for Sarcopenia (AWGS) guidelines. Individuals with low appendicular skeletal muscle mass index (ASMI) (<7.0 kg/m2 for men; <5.4 kg/m2 for women) and low hand grip strength (HGS) (<28 kg for men; <18 kg for women) were defined as the sarcopenia group. Among this group, those who showed low physical performance (≤9 points on the Short Physical Performance Battery (SPPB)) were defined as the severe sarcopenia group. B12 concentrations were classified into insufficient (<350 pg/mL) and sufficient (≥350 pg/mL). Univariate and multivariate logistic regression analyses were used to evaluate the relationship between sarcopenia and B12 levels. Low ASMI showed a high incidence in the B12-insufficient group. However, HGS, SPPB, and the severity of sarcopenia showed no correlation with B12. Further, insufficient B12 may affect muscle quantity rather than muscle strength or physical performance.

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Noncovalent chemistry may offer diversity in the functions and applications for artificial polymers by allowing various ordered-disordered phase transitions in a precisely controlled manner. To verify this notion from a fundamental perspective, we examined an achiral poly(phenylacetylene) derivative with an α-helical structure as a helical-spring polymer for revealing phase changes through control of intramolecular hydrogen bonding with the chiral solvent and temperature. When an amine capable of hydrogen bonding was used as the chiral solvent, either an irreversible helix-helix or a reversible helix-coil phase change occurred in an optically dissymmetric manner according to the amount of the chiral solvent added and ambient temperature. Considering the hydrogen-bonding strength values of the solvent mixture and the thermodynamic parameters, we could predict if the optical-dissymmetry phase changes would occur and, if so, how they occur. Our results were similar to those see for the denaturation of proteins, induced by solvent and temperature, based on helix-coil phase transition.

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Portable miniaturised scanning mobility particle sizer (SMPS) instruments measuring atmospheric particles within the 10-241 nm size range were used to track particle number size distributions and concentrations during near-simultaneous pedestrian, bicycle, bus, car, tram and subway commuting journeys in Barcelona, Spain on 4th-6th July 2018. The majority of particles in this size range were <100 nm, with k-means cluster analysis identifying peaks at 15-22 nm, 30-40 nm, and 45-75 nm. Around 10-25% of the particles measured however were >100 nm (especially in the subway environment) and so lie outside the commonly defined range of "ultrafine" particles (UFP, or <100 nm particles). The study demonstrated in detail how personal exposure to quasi-UFP (QUFP, <241 nm), most of which present in the city streets are produced by road traffic, varies greatly depending on the transport mode and route chosen. Proximity to fresh traffic exhaust sources, such as in a car with open windows, on-road cycling, walking downwind of busy roads, or in a subway station contaminated by roadside air, enhances commuter exposure to particles <30 nm in size. In contrast, travelling inside air-conditioned bus or tram offers greater protection to the commuter from high concentrations of fresh exhaust. Ultrafine number size distributions in traffic-contaminated city air typically peak in the size range 30-70 nm, but they can be shifted to finer sizes not only by increased content of fresh proximal exhaust emissions but also by bursts of new particle formation (NPF) events in the city. One such afternoon photochemical nucleation NPF event was identified during our Barcelona study and recognised in different transport modes, including underground in the subway system. The integration of static urban background air monitoring station information with particle number concentration and size distribution data obtained from portable miniaturised SMPS instruments during commuting journeys opens new approaches to investigating city air quality by offering a level of detail not previously available.

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BACKGROUND: Dysphagia and dysarthria tend to coexist in stroke patients. Dysphagia can reduce patients' quality of life, cause aspiration pneumonia and increased mortality. OBJECTIVE: To evaluate correlations among swallowing function parameters and acoustic vowel space values in patients with stroke. METHODS: Data from stroke patients with dysarthria and dysphagia were collected. The formant parameter representing the resonance frequency of the vocal tract as a two-dimensional coordinate point was measured for the /a/, /ae/, /i/, and /u/vowels, and the quadrilateral vowel space area (VSA) and formant centralization ratio (FCR) were measured. Swallowing function was evaluated by a videofluoroscopic swallowing study (VFSS) using the videofluoroscopic dysphagia scale (VDS) and penetration aspiration scale (PAS). Pearson's correlation and linear regression analyses were used to assess the correlation of VSA and FCR to VDS and PAS scores. RESULTS: Thirty-one stroke patients with dysphagia and dysarthria were analyzed. VSA showed a negative correlation to VDS and PAS scores, while FCR showed a positive correlation to VDS score, but not to PAS score. VSA and FCR were significant factors for assessing dysphagia severity. CONCLUSIONS: VSA and FCR values were correlated with swallowing function and may be helpful in predicting dysphagia severity associated with stroke.

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OBJECTIVE: To propose an artificial intelligence (AI)-based decision-making rule in modified Ashworth scale (MAS) that draws maximum agreement from multiple human raters and to analyze how various biomechanical parameters affect scores in MAS. DESIGN: Prospective observational study. SETTING: Two university hospitals. PARTICIPANTS: Hemiplegic adults with elbow flexor spasticity due to acquired brain injury (N=34). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Twenty-eight rehabilitation doctors and occupational therapists examined MAS of elbow flexors in 34 subjects with hemiplegia due to acquired brain injury while the MAS score and biomechanical data (ie, joint motion and resistance) were collected. Nine biomechanical parameters that quantify spastic response described by the joint motion and resistance were calculated. An AI algorithm (or artificial neural network) was trained to predict the MAS score from the parameters. Afterwards, the contribution of each parameter for determining MAS scores was analyzed. RESULTS: The trained AI agreed with the human raters for the majority (82.2%, Cohen's kappa=0.743) of data. The MAS scores chosen by the AI and human raters showed a strong correlation (correlation coefficient=0.825). Each biomechanical parameter contributed differently to the different MAS scores. Overall, angle of catch, maximum stretching speed, and maximum resistance were the most relevant parameters that affected the AI decision. CONCLUSIONS: AI can successfully learn clinical assessment of spasticity with good agreement with multiple human raters. In addition, we could analyze which factors of spastic response are considered important by the human raters in assessing spasticity by observing how AI learns the expert decision. It should be noted that few data were collected for MAS3; the results and analysis related to MAS3 therefore have limited supporting evidence.

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OBJECTIVE: To evaluate the association between balance function and asymmetry of knee extension strength in an elderly Korean population. METHODS: The strength of the knee extensors in each leg was measured in 306 community-dwelling elderly subjects (age, 76.70±4.85 years) and 25 young healthy subjects (age, 34.23±8.93 years). Based on the difference in strength of both legs, the elderly subjects were divided into symmetric (n=128) and asymmetric (n=178) strength groups using an asymmetry cutoff 20%. We determined the postural control ability of the subjects using InBody posturography, Berg Balance Scale (BBS), Timed Up and Go test (TUG) and Short Physical Performance Battery (SPPB). The sway index (SI) of the subjects in four positions was assessed using posturography. RESULTS: The group with asymmetric strength presented a significantly higher SI than the group with symmetric strength, in the normal position with eyes open and eyes open on pillows. In the normal position with the eyes closed and in postures with the eyes closed on pillows, the statistical analysis revealed no significant differences between the two groups. The three tests for physical performance (BBS, TUG, and SPPB) show no statistically significant difference between the two groups. CONCLUSION: The asymmetric strength group showed a significantly lower balance than the group with symmetric strength based on several posturographic parameters. Ambulatory elderly individuals with asymmetry in knee extension strength, showed deficits in balance control even in normal clinical tests.

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OBJECTIVE: To investigate if walking is independently associated with low back pain (LBP) in the general population. METHODS: This cross-sectional study used public data from the Fourth and Fifth Korean National Health and Nutrition Examination Survey. Subjects included 5,982 community-dwelling adults aged ≥50 years. Presence of current LBP was defined as LBP for 1 month or more in the past 3 months. Walking was measured as total walking duration for the past week and subjects were divided into four quartiles. Independent effect of walking on LBP was determined using odds ratios (OR) adjusted for age, sex, osteoporosis, depression or anxiety, and radiographic lumbar spondylosis. RESULTS: Prevalence of LBP was 26.4% in this population. Older people and women had higher prevalence of current LBP. Prevalence of obesity and osteoporosis was higher in subjects with current LBP and quality of life was poorer in subjects with current LBP. Adjusted logistic regression model revealed that older age (OR, 1.655; p=0.018), female sex (OR, 2.578; p<0.001), radiographic lumbar spondylosis (OR, 2.728; p<0.001), depression or anxiety (OR, 5.409; p<0.001), and presence of osteoporosis (OR, 1.467; p=0.002) were positively associated with current LBP. Walking decreased prevalence of current LBP proportionally (2nd quartile OR, 0.795; 3rd quartile OR, 0.770; and 4th quartile OR, 0.686 compared with the 1st quartile of walking). CONCLUSION: Walking was negatively associated with LBP. Further studies are needed to reveal causal relationship of this phenomenon.

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OBJECTIVE: To assess the cross-sectional area (CSA) of the muscles for investigating the occurrence of asymmetry of the paraspinal (multifidus and erector spinae) and psoas muscles and its relation to the chronicity of unilateral lumbar radiculopathy using magnetic resonance imaging (MRI). METHODS: This retrospective study was conducted between January 2012 to December 2014. Sixty one patients with unilateral L5 radiculopathy were enrolled: 30 patients had a symptom duration less than 3 months (group A) and 31 patients had a symptom duration of 3 months or more (group B). Axial MRI measured the CSA of the paraspinal and psoas muscles at the middle between the lower margin of the upper vertebra and upper margin of the lower vertebra, and obtained the relative CSA (rCSA) which is the ratio of the CSA of muscles to that of the lower margin of L4 vertebra. RESULTS: There were no differences in the demographics between the two groups. In group B, rCSA of the erector spinae at the L4-5 level, and that of multifidus at the L4-5 and L5-S1 levels, were significantly smaller on the involved side as compared with the uninvolved side. In contrast, no significant muscle asymmetry was observed in group A. The rCSA of the psoas was not affected in either group. CONCLUSION: The atrophy of the multifidus and erector spinae ipsilateral to the lumbar radiculopathy was observed only in patients suffering from unilateral radiculopathy for 3 months or more.

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Reliable assessment is essential for the management of spasticity, one of the most frequent complication of various neurological diseases. For the spasticity assessment, several clinical tools have been developed and widely used in clinics. The most popular one is modified Ashworth scale (MAS). It has a simple protocol, but is subjective and qualitative. To improve its reliability, quantitative measurement and consistent training would be needed. This study presents an elbow spasticity simulator which mimics spastic response of adult post stroke survivors. First, spastic responses (i.e. resistance and joint motion) from patients with a stroke were measured during conventional MAS assessment. Each grade of MAS was quantified by using three parameters representing three characteristics of the spasticity. Based on the parameters, haptic models of MAS were developed for implementing repeatable and consistent haptic training of novice clinicians. Two experienced clinicians participated in preliminary evaluation of the models.

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OBJECTIVE: To investigate whether the polymorphisms of CASP3 gene (rs4647602, intron A/C and rs1049216, UTR C/T) and CASP9 gene (rs1052576, Gln/Arg G/A and rs1052571, Ser/Val T/C) were associated with the development, and clinical severity of ischemic stroke and functional consequences after stroke. METHODS: Genomic DNA from 121 ischemic stroke patients and 201 healthy control subjects were extracted, and polymerase chain reaction products were sequenced. To investigate the association of polymorphisms and the development, and National Institutes of Health Stroke Scale (K-NIHSS), logistic regression models were analyzed. RESULTS: Polymorphism of the untranslational region of CASP3 (rs1049216, UTR C/T) has been associated with the development of ischemic stroke-in codominant1 model (odds ratio [OR], 0.51; 95% confidence interval [CI], 0.29-0.88; p=0.017), in dominant model (OR, 0.57; 95% CI, 0.34-0.97; p=0.034), and in the overdominant model (OR, 0.50; 95% CI, 0.29-0.87; p=0.011). A missense SNP of CASP9 gene (rs1052571, Ser/Val T/C) was associated with the development of ischemic stroke (OR, 1.93; 95% CI, 1.05-3.55; p=0.034 in recessive model). CONCLUSION: These results indicate the possibility that CASP3 and CASP9 genes are markers for the development of ischemic stroke.

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OBJECTIVE: To evaluate the relationships between tongue pressure and different aspects of the oral-phase swallowing function. METHODS: We included 96 stroke patients with dysphagia, ranging in age from 40 to 88 years (mean, 63.7 years). Measurements of tongue pressure were obtained with the Iowa Oral Performance Instrument, a device with established normative data. Three trials of maximum performance were performed for lip closure pressure (LP), anterior hard palate-to-tongue pressure (AP), and posterior hard palate-to-tongue pressure (PP); buccal-to-tongue pressures on both sides were also recorded (buccal-to-tongue pressure, on the weak side [BW]; buccal-to-tongue pressure, on the healthy side [BH]). The average pressure in each result was compared between the groups. Clinical evaluation of the swallowing function was performed with a videofluoroscopic swallowing study. RESULTS: The average maximum AP and PP values in the intact LC group were significantly higher than those in the inadequate lip closure group (AP, p=0.003; PP, p<0.001). AP and PP showed significant relationships with bolus formation (BF), mastication, premature bolus loss (PBL), tongue to palate contact (TP), and oral transit time (OTT). Furthermore, LP, BW, and BH values were significantly higher in the groups with intact mastication, without PBL and intact TP. CONCLUSION: These findings indicate that the tongue pressure appears to be closely related to the oral-phase swallowing function in post-stroke patients, especially BF, mastication, PBL, TP and OTT.

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OBJECTIVE: To investigate whether baculoviral inhibitor of apoptosis (IAP) repeat containing 5 gene (BIRC5) polymorphisms are associated with the development and clinical phenotypes of ischemic stroke in Korea population. METHODS: We enrolled 121 ischemic stroke patients and 291 control subjects. Ischemic stroke patients were divided into subgroups according to the scores of National Institutes of Health Stroke Survey (<6 or ≥6) and Modified Barthel Index (<60 or ≥60). Single nucleotide polymorphisms (SNPs) of BIRC5 (rs3764383 and rs2071214) were selected and genotyped by direct sequencing for all subjects. Multiple logistic regression models (codominant 1 and 2, dominant, recessive, overdominant and log-additive) were used to estimate odds ratios (ORs), 95% confidence intervals (CIs), and p-values. RESULTS: In analysis of stroke susceptibility, the genotype and allele frequencies of rs3764383 exhibited no difference between the control group and the ischemic stroke group. SNP rs2071214 was associated with ischemic stroke in the codominant (p=0.003), dominant (p=0.002), overdominant (p=0.005), and log-additive (p=0.008) models, respectively. The G allele frequency of rs2071214 was significantly (p=0.009) associated with susceptibility for ischemic stroke (OR, 1.57; 95% CI, 1.12-2.21). However, in the analysis for clinical phenotype, no SNP of the BIRC5 gene was found to be associated with ischemic stroke. CONCLUSION: These results suggest that a missense SNP (rs2071214) of BIRC5 may be associated with the development of ischemic stroke in the Korean population.

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To investigate the contribution of the interleukin-6 receptor (IL-6R) gene single nucleotide polymorphisms (SNPs) to the neurological status of Korean patients with ischemic stroke (IS), two SNPs of the IL-6R gene (rs4845617, 5 UTR; rs2228144, Ala31Ala) were selected. IS patients were classified into clinical phenotypes according to two well-defined scores: the National Institutes of Health Stroke Survey (NIHSS) and the Modified Barthel Index scores. There were 121 IS patients and 291 control subjects. The SNP rs4845617 significantly contributed to the neurological status of patients with IS (P = 0.011 in codominant model 2, P = 0.006 in recessive model, and P = 0.008 in log-additive model). Allele frequencies of rs4845617 and rs2228144 demonstrated no significant difference in IS patients and controls. The AG and GG haplotypes differed between the NIHSS 1 (NIHSS scores < 6) group and the NIHSS 2 (NIHSS scores ≥ 6) group in patients with IS (P = 0.014, P = 0.0024). These results suggest that rs4845617 of the IL-6R gene is associated with the neurologic status of Korean patients with IS.

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OBJECTIVE: To investigate whether four single nucleotide polymorphisms (SNPs) rs2293054 [Ile734Ile], rs1047735 [His902His], rs2293044 [Val1353Val], rs2682826 (3'UTR) of nitric oxide synthase 1 (NOS1) are associated with the development and clinical phenotypes of ischemic stroke. METHODS: We enrolled 120 ischemic stroke patients and 314 control subjects. Ischemic stroke patients were divided into subgroups according to the scores of the National Institutes of Health Stroke Survey (NIHSS, <6 and ≥6) and Modified Barthel Index (MBI, <60 and ≥60). SNPStats, SNPAnalyzer, and HelixTree programs were used to calculate odds ratios (ORs), 95% confidence intervals (CIs), and p-values. Multiple logistic regression models were performed to analyze genetic data. RESULTS: No SNPs of the NOS1 gene were found to be associated with ischemic stroke. However, in an analysis of clinical phenotypes, we found that rs2293054 was associated with the NIHSS scores of ischemic stroke patients in codominant (p=0.019), dominant (p=0.007), overdominant (p=0.033), and log-additive (p=0.0048) models. Also, rs2682826 revealed a significant association in the recessive model (p=0.034). In allele frequency analysis, we also found that the T alleles of rs2293054 were associated with lower NIHSS scores (p=0.007). Respectively, rs2293054 had a significant association in the MBI scores of ischemic stroke in codominant (p=0.038), dominant (p=0.031), overdominant (p=0.045), and log-additive (p=0.04) models. CONCLUSION: These results suggest that NOS1 may be related to the clinical phenotypes of ischemic stroke in Korean population.

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Dystonia is a movement disorder characterized by involuntary muscle contractions. Patients with dystonia may experience uncontrollable twisting, repetitive movements, or abnormal posture. A 55-year-old man presented with an involuntary left forearm supination, which he had experienced for five years. There was no history of antecedent trauma to the wrist or elbow. Although conventional therapeutic modalities had been performed, the symptoms persisted. When he visited our hospital, electromyography was performed. Reduced conduction velocity was evident at the elbow-axilla segment of the left median nerve. We suspected that there was a problem on the median nerve between the elbow and the axilla. For this reason, we performed an ultrasonography and magnetic resonance imaging study. A spindle-shaped soft tissue mass was observed at the left median nerve that suggested the possibility of neurofibroma. Dystonia caused by traumatic or compressive peripheral nerve injury has often been reported, but focal dystonia due to a neurogenic tumor is extremely rare. Here, we report our case with a review of the literature.