Dye-Containing Polymers with π-Extened Diketopyrropyrrole Derivatives for Semi-transparent Organic Photovoltaics.

Dye-containing polymers P1 (PEDPP-OT-BDT) and P2 (PEDPP-OT-BDTT) including a π-extended diketopyropyrrole (DPP) derivative and electron-rich thiophene fused ring units (4,8-bis((2-ethylhexyl)oxy)benzo[1,2-b:4,5-b']dithiophene for P1 and 4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene for P2) were synthesized as narrow band gap dyes. A π-extended DPP (EDPP-OT-BrPh), fragment of the polymers P1 and P2, was obtained by extending the π-conjugation of DPP using Ru(III)-catalyzed C-H and N-H activation reported by Gonka et al. in 2019, exhibiting a high quantum yield (φem = 0.84) and small HOMO-LUMO gap (Eg = 1.69 eV) due to the spatial overlap of the HOMO and LUMO orbitals. The solubility of the π-extended DPP was improved by introducing four 2-octylthophene side chains around the periphery of the planer dye moiety, while maintaining the high planarity of the dye molecule, which is essential to the function of optoelectronic devices. As a result, P1 and P2, polymerized with the π-extended DPP and BDT derivatives, exhibit carrier mobility of approximately 10-5 cm2/Vs in organic field-effect transistors (OFETs). In bulk heterojunction (BHJ) solar cells with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), they demonstrate a power conversion efficiency (PCE) of 1.0% with an average transmittance (AVTs) of around 60%.

Effects of electrical stimulation of antagonist muscles on shoulder joint adduction force and grip strength.

[Purpose] This study aimed to determine whether applying electrical stimulation to the deltoid and extensor digitorum muscles could lead to a reduction in fixation force during shoulder joint adduction and grip strength. [Participants and Methods] Fifteen healthy adult males participated in this study. In the shoulder adduction force experiment, the middle fibers of the deltoid muscle of the dominant arm were electrically stimulated. In the grip strength experiment, the extensor digitorum muscle of the dominant arm was electrically stimulated. The forces exerted with and without the electrical stimulation were measured. [Results] The torque of the shoulder adduction force decreased significantly with electrical stimulation, while no significant change was observed in normalized grip strength with electrical stimulation. [Conclusion] The response of antagonist muscles to electrical stimulation varied according to location.

Foot Position Measurement during Assistive Motion for Sit-to-Stand Using a Single Inertial Sensor and Shoe-Type Force Sensors.

Assistive motion for sit-to-stand causes lower back pain (LBP) among caregivers. Considering previous studies that showed that foot position adjustment could reduce lumbar load during assistive motion for sit-to-stand, quantitative monitoring of and instructions on foot position could contribute toward reducing LBP among caregivers. The present study proposes and evaluates a new method for the quantitative measurement of foot position during assistive motion for sit-to-stand using a few wearable sensors that are not limited to the measurement area. The proposed method measures quantitative foot position (anteroposterior and mediolateral distance between both feet) through a machine learning technique using features obtained from only a single inertial sensor on the trunk and shoe-type force sensors. During the experiment, the accuracy of the proposed method was investigated by comparing the obtained values with those from an optical motion capture system. The results showed that the proposed method produced only minor errors (less than 6.5% of body height) when measuring foot position during assistive motion for sit-to-stand. Furthermore, Bland-Altman plots suggested no fixed errors between the proposed method and the optical motion capture system. These results suggest that the proposed method could be utilized for measuring foot position during assistive motion for sit-to-stand.

Optimal foot-position of caregiver based on muscle activity of lower back and lower limb while providing sit-to-stand support.

[Purpose] In caregivers, low load posture is necessary to prevent lower back pain during patient handling activities such as sit-to-stand support. This study focused on the foot-position of caregivers as an adjustable and useful parameter. A wide stance decreases the stress on the lumbar vertebra. However, this foot-position increases loading of the spinae erector muscles. The aim of this study was to investigate the relationship of anterior-posterior and lateral-medial distances between feet and activity of the spinae erector muscles to determine the optimal foot-position for reducing stress on the lumbar vertebra without increasing spinae erector muscle load. [Participants and Methods] Five young male participants were asked to provide sit-to-stand support 10 times using nine normalized foot-positions with different anterior-posterior and lateral-medial distances. Surface electromyograms of the erector spinae and lower limb muscles were measured during sit-to-stand support. [Results] The results showed that the optimal foot-position (anterior-posterior 55%, lateral-medial 20% of body height) increased muscle activity within the lower limb muscles compared with the lower back muscles and did not increase loads on the erector spinae muscle. [Conclusion] Optimizing foot-position can reduce stress on the lumbar vertebra without increasing load on the spinae erector muscles.

Usefulness of a simulated experience method for transfer assistance for hemiplegia or limited range of motion in multiple joints.

[Purpose] To further the understanding of dysfunctions to which a simulated experience method could be applied, we clarified whether a simulated experience method can promote caregivers to utilize the abilities of care recipients with pseudo-hemiplegia or pseudo-limited range of motion (ROM) in multiple joints. [Participants and Methods] We studied transfer assistance in 60 nursing assistants from nursing home settings: 30 were assigned to the pseudo-hemiplegia (26 females, 4 males) and limited ROM in multiple joints (27 females, 3 males) groups. One healthy person was fitted with orthotic braces to mimic hemiplegia or limited ROM in multiple joints, each making it difficult to stand-up. Participants were randomized to either a simulated experience group (involving interventional help from a physical therapist between the first and second measurements) or a control group. The load difference on the lower limbs of the care recipient between two rounds of transfer assistance was examined. [Results] The difference between the second and first measurements was -5.9 ± 74.5 N for the control group and 107.9 ± 123.6 N for the simulated experience method in the pseudo-hemiplegia study, and -14.7 ± 64.7 N and 149.1 ± 132.4 N, respectively, for the pseudo-limited ROM-in-multiple-joints study. [Conclusion] The simulated experience method promoted transfer assistance of a care recipient with pseudo-hemiplegia or pseudo-limited ROM in multiple joints. These results suggest that hemiplegia and limited ROM in multiple joints are added as dysfunctions that can be applied to a simulated experience method in transfer assistance.

Relationship between surface electromyography of the spinae erector muscles and subjectively adjusted step length in the supporting standing-up motion.

[Purpose] Caregivers experience low back pain owing to frequent patient handling motions such as supporting the body while standing up. To prevent low back pain in caregivers, low load posture while engaging in patient handling motions is required. We determined the relationship between surface electromyography of the erector spinae muscles and subjective step length as "long" and "short" during the supporting standing-up motions of caregivers. [Participants and Methods] Ten young male participants were asked to perform supporting standing-up motion 10 times using two-step lengths comprised of subjective long and short steps. During supporting standing-up motion, we measured surface electromyograms of the erector spinae muscles and calculated the integral electromyographic values. [Results] The subjective long/short-step length normalized by body height did not differ across the participants. In addition, the subjective long-step length was longer than the subjective short-step length in all the participants. Integral electromyographic values for both the left and right erector spinae muscles in the short-step length were significantly lower than those in the long-step length when the data obtained from all the participants were used. [Conclusion] We considered that the load of the erector spinae muscle will be reduced if the short-step instead of the long-step instruction is given. In the future, instructions based on the subjective step-length variation in caregivers must be considered.

Usefulness of simulation method to improve efficiency of chair-to-wheelchair transfer of patients performed by caregivers.

[Purpose] We aimed to clarify whether demonstration and simulated experience help the ability of care-receivers to get transferred, such as from the bed to the commode. [Participants and Methods] Participants included 28 nurses and 17 caregivers (34 females and 11 males). We developed a total floor reaction force measurement device to quantify the total loading level of care-receivers and caregivers and force shoes to quantify the loading level of the caregivers. Using these instruments, we constructed a system to measure the load on the lower limbs of the care-receivers during partial assistance. We divided the participants into the control, demonstration, and simulated experience method groups. We examined the differences in the load on the lower limbs before and after the intervention. [Results] The loads on the lower limbs of care-receivers when their buttocks were lifted from the chair were 11.7 ± 69.6, 61.8 ± 79.4, and 101.0 ± 104.0 N in the control, demonstration, and simulated experience groups. [Conclusion] These data suggest that the simulated experience method could help make use of the ability of the care-receiver to get transferred. Even care workers for the sanatorium-type sickbeds could learn to utilize the physical ability of the care-receivers using simulated experience.

Influence of electrical stimulation on hip joint adductor muscle activity during maximum effort.

[Purpose] This study investigated whether hip adductor activity was influenced by electrical stimulation of the tensor fascia lata muscle. [Subjects and Methods] The subjects were 16 nondisabled males. Each subject was asked to adduct the hip joint with maximum effort. The electromyogram of the adductor longus was recorded under two experimental conditions, with and without electrical stimulation of the tensor fascia lata. [Results] In the presence of electrical stimulation, muscle activity decreased to 72.9% (57.8-89.3%) of that without stimulation. [Conclusion] These results suggested that inactivation of the adductor group was promoted by electrical stimulation of the tensor fascia lata.

The influence of antagonist muscle electrical stimulation on maximal hip adduction force.

[Purpose] The aim of this study was to determine whether electrical stimulation of the tensor fascia lata muscle decreases voluntary maximum resistance to passive abduction motion in participants without disease of the central nervous system. [Subjects] The participants were 16 healthy men. [Methods] The hip joint was moved from 10° adduction to 0° adduction with an angular velocity of 7°/s. During the passive leg motion, the subject was asked to resist the motion with maximum force. Two experimental conditions were prepared: (1) electrical stimulation provided to the tensor fascia lata muscle during the passive motion; and (2) no electrical stimulation provided. [Results] The force was 10.2 ± 3.5 kgf with electrical stimulation and 12.2 ± 3.8 kgf without electrical stimulation. [Conclusion] The results suggested that the maximum hip adduction force decreased in participants because of electrical stimulation of the tensor fascia lata muscle.