Detecting differences in limb load asymmetry during walking between older adult fallers and non-fallers using in-shoe sensors

BACKGROUND

Previous studies have reported that clinical walk tests could not detect differences between fallers and non-fallers in older adults. With advancements in wearable technology, it may be possible to assess differences in loading parameters in clinical settings using portable data collection methods.

RESEARCH QUESTION

The purpose of this study was to determine if wearable sensors (loadsol®) are reliable for assessing asymmetry of contact time, peak force, loading rate (LR), and impulse in older adults and determine if the insole can detect differences in these parameters between fallers and non-fallers during walking.

METHODS

Fifty-five older adults (74.1 ± 6.1 years) walked at their maximum speed on a flat floor. Force data were collected from insoles (100 Hz) during a 10-m walk test. To assess reliability, an intraclass correlation coefficient [ICC(2,k)] was generated for each asymmetry variable. To determine differences between fallers and non-fallers, analysis of covariance (ANCOVA; covariate: body mass index) was completed for each variable.

RESULTS

The ICC of peak force asymmetry (PFA) was 0.942, but other ICCs were less than 0.75. The ANCOVA results indicate that the loadsol® can detect differences in PFA between fallers and non-fallers. The PFA was significantly greater in fallers than in non-fallers.

SIGNIFICANCE

The ability to collect force data while walking using loadsol® has the potential to broaden the research questions investigated, explore clinical applications, and increase generalizability.

Fluctuations in Upper and Lower Body Movement during Walking in Normal Pressure Hydrocephalus and Parkinson's Disease Assessed by Motion Capture with a Smartphone Application, TDPT-GT

We aimed to capture the fluctuations in the dynamics of body positions and find the characteristics of them in patients with idiopathic normal pressure hydrocephalus (iNPH) and Parkinson's disease (PD). With the motion-capture application (TDPT-GT) generating 30 Hz coordinates at 27 points on the body, walking in a circle 1 m in diameter was recorded for 23 of iNPH, 23 of PD, and 92 controls. For 128 frames of calculated distances from the navel to the other points, after the Fourier transforms, the slopes (the representatives of fractality) were obtained from the graph plotting the power spectral density against the frequency in log-log coordinates. Differences in the average slopes were tested by one-way ANOVA and multiple comparisons between every two groups. A decrease in the absolute slope value indicates a departure from the 1/f noise characteristic observed in healthy variations. Significant differences in the patient groups and controls were found in all body positions, where patients always showed smaller absolute values. Our system could measure the whole body's movement and temporal variations during walking. The impaired fluctuations of body movement in the upper and lower body may contribute to gait and balance disorders in patients.

Artificial Intelligence Distinguishes Pathological Gait: The Analysis of Markerless Motion Capture Gait Data Acquired by an iOS Application (TDPT-GT)

Distinguishing pathological gait is challenging in neurology because of the difficulty of capturing total body movement and its analysis. We aimed to obtain a convenient recording with an iPhone and establish an algorithm based on deep learning. From May 2021 to November 2022 at Yamagata University Hospital, Shiga University, and Takahata Town, patients with idiopathic normal pressure hydrocephalus (n = 48), Parkinson's disease (n = 21), and other neuromuscular diseases (n = 45) comprised the pathological gait group (n = 114), and the control group consisted of 160 healthy volunteers. iPhone application TDPT-GT captured the subjects walking in a circular path of about 1 meter in diameter, a markerless motion capture system, with an iPhone camera, which generated the three-axis 30 frames per second (fps) relative coordinates of 27 body points. A light gradient boosting machine (Light GBM) with stratified k-fold cross-validation (k = 5) was applied for gait collection for about 1 min per person. The median ability model tested 200 frames of each person's data for its distinction capability, which resulted in the area under a curve of 0.719. The pathological gait captured by the iPhone could be distinguished by artificial intelligence.

Relationship between foot morphology, muscle strength, and physical performance test in women aged 65 years and older: a cross-sectional study

Background

Hallux valgus is a foot deformity that may affect gait, thus increasing the risk of falls among older people. We investigated the relationship between foot morphology, muscle strength, and physical performance.

Methods

In this study, community-dwelling older people aged ≥65 years were included. A three-dimensional footprint automatic measurement apparatus was used to measure the hallux valgus angle, arch height ratio, and heel-floor angle. Furthermore, the toe flexor strength and ankle plantar flexion strength were measured. Physical performance tests included the five-repetition sit-to-stand test, one-leg standing time, maximal step length, functional reach test, and 5-m fastest walking time (walking time). The relationship between the hallux valgus angle and foot morphology and muscle strength was examined. In addition, factors affecting physical performance testing were assessed. Two-group comparisons, correlation, and multiple comparisons were used for statistical analyses.

Results

Of the 133 women (age 77.7 ± 6.2 years), 57 had hallux valgus and 76 had no hallux valgus. There was a significant difference in the arch height ratio and heel-floor angle between women with and without hallux valgus (p < 0.001). A correlation was found between the hallux valgus angle and the heel-floor angle (r = 0.468, p < 0.001) and arch height ratio (r = − 0.337, p < 0.001), respectively. Multiple regression analysis showed that the hallux valgus angle was related to functional reach (β = − 0.162, p = 0.042), and toe flexor strength was related to five-repetition sit-to-stand (β = − 0.182, p = 0.036), maximal step length (β = 0.328, p < 0.001), and walking time (β = − 0.219, p = 0.006).

Conclusions

A relationship was found between the hallux valgus angle, arch height rate, and inward inclination angle of the calcaneus. Functional reach was predicted based on the hallux valgus angle, whereas the five-repetition sit-to-stand, maximal step length, and walking time were predicted based on toe flexor strength. Hallux valgus predicted not only the forefoot but also the foot morphology and was related to physical performance. From the perspective of motor function and fall prevention, efforts should be made to better understand and prevent the onset and progression of hallux valgus.

Effects of self-management exercise group participation in community-dwelling older adults

Background

The effects of physical fitness and age on motor function in older adults who continue to exercise remain unclear. This study aimed to examine the effects of participation in self-management exercise groups in adults aged ≥65 years.

Methods

The motor functions of 372 citizens who participated in a self-management exercise group for 1 year were examined. The motor functions were assessed by measuring grip strength, five-repetition sit-to-stand test, 5-m fastest walking time (walking time) and timed up and go test. The participants were grouped according to their baseline grip strength (low or high grip strength groups). The baseline parameters were compared to those assessed 1 year after group participation. In addition, the rates of long-term care/support need certification were examined at 2-year follow-up.

Results

In the low grip strength group aged ≥75 years, the grip strength of men, and grip strength and five-repetition sit-to-stand test results of women improved after 1 year. In the high grip strength group, the five-repetition sit-to-stand and timed up and go test results of men aged 65–74 years and five-repetition sit-to-stand test results of men aged ≥75 years improved. Among women in the high grip strength group, grip strength, five-repetition sit-to-stand test, walking time, and timed up and go test results improved in the participants aged 65–74 and ≥ 75 years. The number of new long-term care/support need certifications was comparable in both groups.

Conclusions

Participation in self-management exercise groups led to maintaining or improving physical fitness among community-dwelling-older adults. Furthermore, higher baseline grip strength was associated with improvements in many motor functions; therefore, participation in self-management exercise groups before the onset of functional decline is desirable.

Synthesis, antibacterial activities, and sustained perfume release properties of optically active5-hydroxy- and 5-acetoxyalkanethioamide analogues

5-Acetoxy- and 5-hydroxyalkanethioamide analogues showed high antibacterial activity against Staphylococcus aureus. Antibacterial thioamides were prepared from 5-alkyl-δ-lactones by amidation, thionation, and subsequent deacetylation. Optically active thioamides with 99% diastereomeric excesses were prepared by diastereomeric resolution using Cbz-L-proline as the resolving agent. Antibacterial thioamides were slowly lactonized by a lipase catalyst. Therefore, these thioamides are potential sustained-release perfume compounds having antibacterial properties.

Spouse's functional disability and mortality: The Ohsaki Cohort 2006 Study

Aim

Caregiver burden is known to negatively affect a partner's health. Given the important role of physical and mental stress in mortality, a higher caregiver burden might be associated with an increased incidence of fatal events. However, previous studies of the effects of the partner's caregiving on mortality have shown inconsistent results. Thus, the purpose of the present longitudinal study was to determine if there is an association between a spouse's functional disability and mortality in the older Japanese population.

Methods

A baseline survey was carried out with 7598 participants in 2006. Information on the date of functional disability, death or emigration was retrieved from the Ohsaki City government. Functional disability was defined as receiving a certification for long‐term care insurance in Japan. After a follow‐up period of a maximum of 87 months, 1316 of the participants died and Cox regression analysis with adjustment for confounding factors was used to assess mortality after the incidence of functional disability in a spouse.

Results

The multivariate adjusted hazard ratio for mortality was 1.78 (95% confidence interval 1.52–2.08, P < 0.01) in those whose spouses had functional disabilities compared with those with spouses who did not have functional disabilities. The mortality was consistently higher, irrespective of age group or sex.

Conclusions

These results imply that caregiver burden might increase stress responses and lead to increased mortality; therefore, enhancement of support systems, including long‐term care, housing and livelihood support services, for those with disability and their spouses might be important for preventing deaths. Geriatr Gerontol Int 2019; 19: 774–779.

All-cause mortality among Japanese whose cohabiting partners are diagnosed with cancer: the Ohsaki Cohort 2006 study

BACKGROUND

It has been noted that not only adverse psychosocial health effects but also mortality might increase for a person living with a spouse with cancer. This study examined the association between a partner's cancer diagnosis and mortality among a Japanese population.

METHODS

In December 2006, a survey was conducted on participants aged 40 years or older who were residing in northeastern Japan. We identified couples using municipality-specific household ID numbers by searching public records and confirmed partner's cancer diagnosis after the baseline measurement using regional cancer registration information. After following up for a maximum of 4.0 years with the participants regarding mortality and emigration by reviewing the Residential Registry Record, we used Cox's proportional hazards regression to estimate the hazard ratio (HR) of all-cause mortality.

RESULTS

We identified 25,938 participants (12,969 pairs) and included them in the analyses. A total of 1,308 (5.0%) participants had partners with a cancer diagnosis after baseline. The study found no association between a partner's cancer diagnosis and all-cause mortality; multivariable HRs of all-cause mortality for individuals in exposed subjects compared with those in unexposed subjects were 1.35 (95% confidence interval [CI] = 0.99-1.83; p = .055). Contrarily, sensitivity analyses of mortality attributed to having partners diagnosed with cancer based on the time since entry showed that all-cause mortality significantly increased only within one year from spouse cancer diagnosis; HR = 2.18 (95% CI = 1.44-3.30; p < .01).

CONCLUSIONS

Our findings reveal that the mortality rate from partner's cancer diagnosis was significantly high during the early period of diagnosis and multidisciplinary teams for cancer treatment might be important for preventing death among the partner.

The State Scientific Automated Medical Registry, Kazakhstan: an important resource for low-dose radiation health research

Direct quantitative assessment of health risks following exposure to ionizing radiation is based on findings from epidemiological studies. Populations affected by nuclear bomb testing are among those that allow such assessment. The population living around the former Soviet Union's Semipalatinsk nuclear test site is one of the largest human cohorts exposed to radiation from nuclear weapons tests. Following research that started in the 1960s, a registry that contains information on more than 300,000 individuals residing in the areas neighboring to the test site was established. Four nuclear weapons tests, conducted from 1949 to 1956, resulted in non-negligible radiation exposures to the public, corresponding up to approximately 300 mGy external dose. The registry contains relevant information about those who lived at the time of the testing as well as about their offspring, including biological material. An international group of scientists worked together within the research project SEMI-NUC funded by the European Union, and concluded that the registry provides a novel, mostly unexplored, and valuable resource for the assessment of the population risks associated with environmental radiation exposure. Suggestions for future studies and pathways on how to use the best dose assessment strategies have also been described in the project. Moreover, the registry could be used for research on other relevant public health topics.

Evidence for a white matter lesion size threshold to support the diagnosis of relapsing remitting multiple sclerosis

BACKGROUND

The number of white matter lesions (WML) in brain MRI is the most established paraclinical tool to support the diagnosis of multiple sclerosis (MS) and to monitor its course. Diagnostic criteria have stipulated a minimum detectable diameter of 3 mm per WML, although this threshold is not evidence-based. We aimed to provide a rationale for a WML size threshold for three-dimensional MRI sequences at 3 T by comparing patients with relapsing-remitting MS (RRMS) to control subjects (CS).

METHODS

We analyzed MR images from two cohorts, obtained at scanners from two different vendors, each comprising patients with RRMS and CS. Both cohorts were examined with FLAIR and T1w sequences. In total, 232 patients with RRMS (Expanded Disability Status Scale: mean = 1.6 ± 1.2; age: mean = 36 ± 10) as well as 116 age- and sex-matched CS were studied. We calculated odds ratios across WML volumes. The WML size threshold, which discriminated best between patients and CS, was estimated with receiver operating characteristic curve analysis.

RESULTS

In both cohorts, odds ratios increased continuously with increasing WML volumes, and discriminative power was highest at a WML size threshold corresponding to a diameter of about 3 mm.

CONCLUSION

The stipulated WML size threshold of 3 mm in diameter for the diagnostic criteria of MS seems a reasonable choice for three-dimensional MRI sequences at 3 T.

Functional disability among partners and community activity in elderly Japanese: The Ohsaki Cohort 2006 Study

INTRODUCTION

This cross-sectional study aimed to determine association between partners' functional disability and community activity in an elderly Japanese population.

METHODS

A baseline survey was conducted between December 1 st and December 15th, 2006 and included 6600 participants from whom we collected data regarding their participation in community activity and functional disability among their partners. We defined functional disability as receiving certification for long-term care insurance in Japan, and frequent community activity as engaging in community activity more than once a month. Multiple logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for frequent community activity based on functional disability among partners. We also conducted additional analyses using three types of community activities (neighborhood associations; sports, exercise, or a hobby; and volunteering for nonprofit organizations) as outcomes.

RESULTS

Multivariate adjusted analysis showed that the OR (95% CI) for frequent community activity was 0.70 (0.54-0.89, P < 0.01) among those whose partners had functional disabilities, compared with those whose partners did not have functional disabilities. This finding remained true even for different types of community activities such as neighborhood activities, sports, exercises, hobbies, and volunteering for nonprofit organizations.

CONCLUSION

In this cross-sectional study of an elderly Japanese population, participants whose partners had functional disabilities were less likely to participate in community activity. We conclude that enhancement of support systems is important to promote participation in community activity, not only for patients with disability but their partners as well.

Synthesis of various β-D-glucopyranosyl and β-D-xylopyranosyl hydroxybenzoates and evaluation of their antioxidant activities

Various β-D-glucopyranosyl and β-D-xylopyranosyl hydroxybenzoates were efficiently prepared from 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (TAGB) or 2,3,4-tri-O-acetyl-α-D-xylopyranosyl bromide (TAXB), respectively, by amine-promoted glycosylation. Regioselective deacetylation of the resulting acetylated β-D-gluco- and β-D-xylopyranosyl hydroxybenzoates was investigated using Novozym 435 as a lipase catalyst. In the case of β-D-glucopyranosyl hydroxybenzoates, Novozym 435-catalyzed deacetylation is regioselective at C-4 and C-6 positions. On the other hand, β-D-xylopyranosyl hydroxybenzoates are deacetylated only at the C-4 position. Antioxidant activities of free hydroxybenzoic acids and the respective β-D-gluco- and β-D-xylopyranosyl hydroxybenzoates were evaluated by DPPH˙ radical scavenging as well as their inhibitory effect on autoxidation of bulk methyl linoleate. The β-D-xylopyranosyl protocatechoate, as well as quercetin and α-tochopherol, show high antioxidant activity for the radical scavenging activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH˙). In bulk methyl linoleate, the antioxidant activities of β-D-gluco- and β-D-xylopyranosyl protocatechoates are higher than that of α-tocopherol.

Preparation of Optically Active δ-Tri- and δ-Tetradecalactones by a Combination of Novozym 435-catalyzed Enantioselective Methanolysis and Amidation

A combination of Novozym 435-catalyzed methanolysis and amidation using racemic N-methyl-5-acetoxytridecan- and tetradecanamides as a substrate proceeded in good enantioselectivity to afford the corresponding (R)-N-methyl-5-acetoxyalkanamides, (S)-N-methyl-5-hydroxyalkanamides, and (S)-N-cyclohexyl-5-hydroxyalkanamides. Both enantiomers of δ-tri- and δ-tetradecalactones were synthesized in over 90% enantiomeric excesses from the corresponding (R)- or (S)-alkanamides. Addition of cyclohexylamine to Novozym 435-catalyzed methanolysis shortened 24-hour reaction time to reach about 50% conversion. Enantiomers of optically active δ-tri- and δ-tetradecalactones had different odors and thresholds.

Deterministic effect of lens at leukergy of patients who received low doses of ionising radiation

To explore the possibility to use the lens extract as an in vitro stimulator to conduct a test of stimulated leukergy in liquidators of the accident consequences (LAC) on Chernobyl Nuclear Power Plant (CNPP) with a cataract in the long-term period. The study sample included 72 men-LAC on CNPP, at the age from 42 to 65 y, who have a cataract. The comparison group consisted of 60 men, with a cataract, of the same age, and who were not exposed to radiation. The control group was composed of 60 men, at the age of 42-58 y without lens pathology. Phenomenon of the stimulated leukergy was revealed in persons who had been exposed to radiation in the dose of 18.2 ± 0.58 cGy and was observed in 5.7-8.05 % (P < 0.001), suggesting a continued high auto-aggression to the lens antigens, and the strength of cell-mediated immunity.

Preparation of optically active 4-substituted γ-lactones by lipase-catalyzed optical resolution

Optically active 4-substituted γ-lactones (3 and 4) were synthesized effectively using lipase-catalyzed optical resolution. N-methyl-4-hydroxyalkanamides (rac-1a–i) as substrates were prepared from N-methylsuccinimide. The alkylation of N-methylsuccinimide using Grignard reagents generated from various alkyl halides followed by reduction resulted in N-methyl-4-hydroxyalkanamides. The optical resolution of rac-1a–g was performed using Novozym 435-catalyzed stereoselective acetylation. The stereoselective preparation of 4-substituted γ-lactones (3 and 4) possessing various side chains such as isopentyl, phenyl, and phenethyl groups was achieved with more than 90% enantiopurity.

Estimation of the contribution of short-lived radioiodines to the thyroid dose for the public in case of inhalation intake following the Fukushima accident

The purpose of this paper is to present (1) the method of assessing the contribution of short-lived radioiodines to the thyroid for members of the public in Fukushima and neighbouring prefectures based on available data and (2) the results of a realistic assessment of such a contribution. The estimates of that contribution for the inhalation intake that occurred on the day of the main fallout (15 March 2011) are within 15 % of the dose to the thyroid from (131)I. The contribution to the thyroid dose from intake of (132)Te is higher than that from the intake of (133)I by a factor of ∼3. The contribution of short-lived radioiodines to the thyroid dose for the public in the case of inhalation intake occurring as early as March 12 might be as great as 30-40 %.

Preparation of optically pure δ-lactones using diastereomeric resolution with amino acid as resolving agent

Synthesis of optically pure δ-lactones by diastereomeric resolution was investigated. Amino acid derivatives, which can be obtained at a relatively low cost, were used as resolving agents. Six optically pure δ-lactones were efficiently synthesized using Cbz-L-alanine without other expensive resolving agents. Both enantiomers of δ-lactone obtained had over 98% enantiomeric excesses. This diastereomeric resolution is very efficient for the preparation of optically pure δ-lactones.

One-pot synthesis of 1-arylmethyl-4-[(E)-alk-1-enyl]-1H-1,2,3-triazoles via a cross-coupling/click reaction sequence

1-Arylmethyl-4-[(E)-alk-1-enyl]-1H-1,2,3-triazoles have been synthesized from terminal conjugated (E)-enynes, prepared by copper-mediated cross-coupling reaction of (E)-alk-1-enyldisiamylboranes with (trimethylsilyl)ethynyl bromide, benzyl bromides and sodium azide in a one-pot fashion.

Distribution of 60Co in steel samples from Hiroshima

This paper describes ultra low-level gamma-ray spectrometry measurements of the (60)Co activity distribution inside one 52 mm and one 41 mm thick steel sample. The samples had been exposed to the Hiroshima atomic bomb and were from the Aioi bridge and the Yokogawa bridge. Both samples were measured in a recent study aiming to back up model calculation of Hiroshima dosimetry. The (60)Co activity distributions found in this study support the assumptions made in the previous study.

The predictive power of physical function assessed by questionnaire and physical performance measures for subsequent disability

BACKGROUND AND AIMS

To compare the predictive power of physical function assessed by questionnaire and physical performance measures for subsequent disability in community-dwelling elderly persons.

METHODS

Prospective cohort study. Participants were 813 aged 70 years and older, elderly Japanese residing in the community, included in the Tsurugaya Project, who were not disabled at the baseline in 2003. Physical function was assessed by the questionnaire of "Motor Fitness Scale". Physical performance measures consisted of maximum walking velocity, timed up and go test (TUG), leg extension power, and functional reach test. The area under the curve (AUC) of the receiver operating characteristic curve for disability was used to compare screening accuracy between Motor Fitness Scale and physical performance measures. Incident disability, defined as certification for long-term care insurance, was used as the endpoint.

RESULTS

We observed 135 cases of incident disability during follow-up. The third or fourth quartile for each measure was associated with a significantly increased risk of disability in comparison with the highest quartile. The AUC was 0.70, 0.72, 0.70, 0.68, 0.69 and 0.74, for Motor Fitness Scale, maxi- mum walking velocity, TUG, leg extension power, functional reach test, and total performance score, respectively.

CONCLUSIONS

The predictive power of physical function assessed by the Motor Fitness Scale was equivalent to that assessed by physical performance measures. Since Motor Fitness Scale can evaluate physical function safely and simply in comparison with physical performance tests, it would be a practical tool for screening persons at high risk of disability.

Lower plasma arginine in enteral tube-fed patients with pressure ulcer and improved pressure ulcer healing after arginine supplementation by Arginaid Water

OBJECTIVES

To determine the presence or extent of arginine deficiency in pressure ulcer (PU) patients on percutaneous endoscopic gastrostomy (PEG) feeding and to examine the effects of arginine supplementation on PU healing.

DESIGN

All eligible PEG patients, with and without PU, were cross-sectionally assessed for plasma arginine. Three-month supplementation with arginine-enriched water (Arginaid Water) was performed on a subset of patients with PU. This intervention study was a prospective, non-controlled trial with 5 PU patients.

SETTING

Geriatric ward of a rural clinical hospital in Japan.

PARTICIPANTS

Thirty-nine inpatients with PEG feeding were assessed for plasma arginine. Five of the 13 patients with PU and five of 26 patients without PU underwent amino acid profiling.

INTERVENTION

Five of the patients with PU received Arginaid Water supplementation.

MEASUREMENTS

Plasma amino acid measurements and biochemical analyses were performed. For those with PU on Arginaid Water supplementation, plasma arginine concentration and PU status were monitored every month.

RESULTS

Patients with PU showed significantly lower plasma arginine concentration compared to those without PU (control vs. PU; 80.2±21.3 vs 62.8±14.7 nmol/ml, p<0.01). After the addition of Arginaid Water, plasma arginine concentration increased (before vs 3 months later; 57.9±1.8 vs 83.1±8.5, p<0.01), and PU area, perimeter, DESIGN-R and PUSH scores significantly improved.

CONCLUSION

Plasma arginine was lower in PEG patients with PU. The healing rate of PU is improved with Arginaid Water supplementation. The findings from this study support the use of arginine supplementation in PEG patients with PU.

Feasibility of using 236U to reconstruct close-in fallout deposition from the Hiroshima atomic bomb

The first results on the feasibility of using (236)U to reconstruct the level and spatial distribution of close-in fallout deposition from the Hiroshima A-bomb are reported, coupled with the use of global fallout (137)Cs and (239+240)Pu. The results for global fallout (236)U in soil samples (0-30cm) from Ishikawa prefecture showed that the deposition density of (236)U from the global fallout can be accurately evaluated using AMS. All deposited (236)U, (137)Cs and (239+240)Pu appeared to have been recovered using 30-cm cores. It was also noted from the depth profiles for (236)U/(239+240)Pu and (236)U/(137)Cs ratios that the downward behavior of (236)U in the soil was apparently similar to that of (239+240)Pu, while the (137)Cs was liable to be retained in upper layers compared with (236)U and (239+240)Pu. The accumulated levels were 1.78×10(13)atomsm(-2) for (236)U, 4340Bqm(-2) for (137)Cs and 141Bqm(-2) for (239+240)Pu. The ratios of (236)U/(137)Cs and (236)U/(239+240)Pu were (4.10±0.12)×10(9) and (1.26±0.04)×10(11)atomsBq(-1), respectively. Results of (236)U, (137)Cs and (239+240)Pu measurements for the seven soil cores (0-30cm) from Hiroshima were discussed on the basis of ratios of (236)U/(137)Cs and (236)U/(239+240)Pu by comparing with those from the background area in Ishikawa, indicating that the global fallout dominates the current level of (236)U accumulation in soil in the Black-rain area around Hiroshima after the Hiroshima bomb, and the contribution of the close-in fallout (236)U produced by the Hiroshima A-bomb seems difficult to observe.

Pharmacokinetics and disposition of CS-8958, a long-acting prodrug of the novel neuraminidase inhibitor laninamivir in rats

CS-8958, a prodrug of laninamivir (R-125489), is currently under development as an inhaled anti-influenza drug. In this study, the pharmacokinetics and disposition of CS-8958 were characterized in rats. After intratracheal administration of 14C-CS-8958, radioactivity was retained over long periods in the target tissues (trachea and lung) as its active metabolite R-125489 - 19.12% of the dose was retained in the lung at 24 h. After intratracheal administration of CS-8958, plasma R-125489 concentration was slowly eliminated, and its half-life (14.1 h) was considerably longer than that after intravenous administration of R-125489. The radioactivity of intratracheally administered 14C-CS-8958 was mainly excreted into the urine (67.5% of dose), and this excretion lasted over long periods. R-125489 accounted for most of the urinary radioactivity recovered after 24 h. These results demonstrated that CS-8958 administered intratracheally to rats was converted/hydrolysed to R-125489 in the target tissues, and that the R-125489 was slowly excreted into the urine via an absorption rate-limiting process. Such distinctive pharmacokinetics attributed to the slow release of R-125489 suggests the potential for a long-acting anti-influenza drug.

Dental enamel EPR dosimetry: comparative testing of the spectra processing methods for determination of radiation-induced signal amplitude

The aim of this investigation is to find out the optimal algorithm for mathematical processing of the EPR spectra of irradiated tooth enamel for estimating the amplitude of the radiation-induced signal, which is used for determination of the absorbed dose in enamel for retrospective individual dosimetry. A recently developed analytical model, which takes into account the line shape variation of the enamel EPR spectral components registered at different microwave power, was applied to spectra processing in various operation modes to simulate spectra processing techniques differing by the number of fitted parameters. The precision of dose determination at spectra processing was assessed by the root mean square deviation between experimental and nominal doses for sets of spectra of enamel samples irradiated in different doses and measured at different microwave power. It is shown that in the case of pooled enamel samples prepared as a mixture from different teeth, the higher precision of spectra processing is obtained using a model with fixed native background signal line shape (characterized by width and asymmetry parameters). In case of individual samples prepared each from a different tooth, better results are obtained using a model with variable background signal line shape.

The neutron dose conversion coefficients calculation in human tooth enamel in an anthropomorphic phantom

In the present study, MCNP4B simulation code is used to simulate neutron and photon transport. It gives the conversion coefficients that relate neutron fluence to the dose in tooth enamel (molars and pre-molars only) for 20 energy groups of monoenergetic neutrons with energies from 10-9 to 20 MeV for five different irradiation geometries. The data presented are intended to provide the basis for connection between EPR dose values and standard protection quantities defined in ICRP Publication 74. The results of the calculations for critical organs were found to be consistent with ICRP data, with discrepancies generally less than 10% for the fast neutrons. The absorbed dose in enamel was found to depend strongly on the incident neutron energy for neutrons over 10 keV. The dependence of the data on the irradiation geometry is also shown. Lower bound estimates of enamel radiation sensitivity to neutrons were made using obtained coefficients for the secondary photons. Depending on neutron energy, tooth enamel was shown to register 10-120% of the total neutron dose in the human body in the case of pure neutron exposure and AP irradiation geometry.

The consideration of biological effectiveness of low energy protons using biophysical modeling of the effects induced by exposure of V79 cells

We have applied Monte Carlo track structure simulations to estimate relative biological effectiveness (RBE) of low-energy protons using biophysical modelling of radiation effects induced by exposure of V79 cells growing in mono-layer. The microscopic energy deposition in cell nucleus and sub-nucleus volumes was investigated in order to understand the reasons of enhanced biological effectiveness near Bragg peak. Theoretical estimations of RBE based on frequency/dose average lineal energy and calculated yields of initial DNA breaks were collated with experimental RBE(M) data. It was found: 1) dose average lineal energy for whole cell nucleus as a function of proton energy shows a distinct peak at 550 keV; 2) the peak values for sub-nucleus volumes are large compared with the whole cell nucleus; 3) the yield of complex DNA breaks correlates with experimental RBE(M) data.

Iron(II) Sulphate (Fricke Solution) Oxidation Yields for 8·9 and 13·6keV X-rays from Synchrotron Radiation

The oxidation yields (G) for 8.86 and 13.55 keV X-rays produced by synchrotron radiation were measured using an iron(II) sulphate (Fricke) solution. Monoenergetic X-rays were produced using a silicon crystal monochromator. The X-rays were absorbed in 0.4 M sulphuric acid-iron(II) sulphate solution and FeIII ion yields were measured and corrected for escape fractions resulting from scattering using Monte Carlo calculations. Doses in the solution were determined using a thin window, parallel plate chamber calibrated against a primary standard free-air chamber at the Electrotechnical Laboratory (Osaka, Japan). Yields (G) of 1.50 +/- 0.06 and 1.43 +/- 0.06 mumol J-1 were obtained for 8.86 and 13.55 keV X-rays respectively.