Effects of a Nanophase-Separated Structure on Mechanical Properties and Proton Conductivity of Acid-Infiltrated Block Polymer Electrolyte Membranes under Non-Humidification

Acid-infiltrated block polymer electrolyte membranes adopting a spherical or lamellar nanophase-separated structure were prepared by infiltrating sulfuric acid (H₂SO₄) into polystyrene-b-poly(4-vinylpyridine)-b-polystyrene (S-P-S) triblock copolymers to investigate the effects of its nanophase-separated structure on mechanical properties and proton conductivities under non-humidification. Lamellae-forming S-P-S/H₂SO₄ membranes with a continuous hard phase generally exhibited higher tensile strength than sphere-forming S-P-S/H₂SO₄ membranes with a discontinuous hard phase even if the same amount of Sa was infiltrated into each neat S-P-S film. Meanwhile, the conductivities of lamellae-forming S-P-S/H₂SO₄ membranes under non-humidification were comparable or superior to those of sphere-forming S-P-S/H₂SO₄ membranes, even though they were infiltrated by the same weight fraction of H₂SO₄. This result is attributed to the conductivities of S-P-S/H₂SO₄ membranes being greatly influenced by the acid/base stoichiometry associated with acid-base complex formation rather than the nanophase-separated structure adopted in the membranes. Namely, there are more free H₂SO₄ moieties that can release free protons contributing to the conductivity in lamellae-forming S-P-S/H₂SO₄ membranes than sphere-forming S-P-S/H₂SO₄, even when the same amount of H₂SO₄ was infiltrated into the S-P-S.

Factors associated with Finnish home care workers job satisfaction

Background

In Finland, home care is seen as a primary form of care for older people. However, rising numbers of clients with increasingly complex conditions have led to deteriorated working conditions and poor job satisfaction among home care staff. In this study, we examined if greater amount of direct care time, higher team autonomy, number of unique clients, and client’s need for care are associated with job satisfaction.

Methods

Data for the study was collected in October 2021. The amount of direct care and number of unique clients were obtained from a staff time measurement in home care units. The level of team autonomy was obtained from a survey sent to managers of participating organizations. Demographic information and a score for job satisfaction were retrieved from a survey for workers in the participating organizations. Client’s need for care was based on Resident Assessment Instrument (RAI). Data was analyzed using multiple linear regression.

Results

The number of respondents was 387, of which the majority were practical nurses 307 (79%). Higher team autonomy was associated with better job satisfaction, whereas higher number of unique clients and higher amount of direct care time were associated with poorer job satisfaction. The models were adjusted with clients’ care needs, but these effects will be further examined.

Conclusions

The results demonstrated that the workers are more satisfied if there is enough time to perform the work, they have adequate number of clients, and teams have autonomy over their work. This seems to be the case despite the level of clients’ need for care, however this needs further analysis. By increasing job satisfaction, better retention of care workers and attraction of care work might be achieved.

Key messages

• Higher team autonomy is associated with care worker’s job satisfaction.

• Enhancing care continuity is important, therefore, when planning home care workers’ workday, it is important to consider that the workers could work with clients they know.

Highly Impact-Resistant Block Polymer-Based Thermoplastic Elastomers with an Ionically Functionalized Rubber Phase

There has been a great deal of interest in incorporating noncovalent bonding groups into elastomers to achieve high strength. However, the impact resistance of such elastomers has not been evaluated, even though it is a crucial mechanical property in practical usage, partly because a large-scale synthetic scheme has not been established. By ionizing the rubber component in polystyrene-b-polyisoprene-b-polystyrene (SIS), we prepared several tens of grams of SIS-based elastomers with an ionically functionalized rubber phase and a sodium cation (i-SIS(Na)) or a bulky barium cation (i-SIS(Ba)). The i-SIS(Na) and i-SIS(Ba) exhibited very high tensile toughness of 520 and 280 MJ m-3, respectively. They also exhibited excellent compressive resistance. Moreover, i-SIS(Ba) was demonstrated to have a higher impact resistance, that is, more protective of a material being covered compared to covering by typical high-strength glass fiber-reinforced plastic. As such elastomers can be produced at an industrial scale, they have great market potential as next-generation elastomeric materials.

Differences in subtrochanteric and diaphyseal atypical femoral fractures in a super-aging prefectural area: YamaCAFe Study

INTRODUCTION

Atypical femoral fractures (AFFs) have been correlated with long-term use of bisphosphonates (BPs), glucocorticoids (GCs), and femoral geometry. We investigated the incidence and characteristics of subtrochanteric (ST) and diaphyseal (DP) AFFs in all institutes in a super-aging prefectural area.

MATERIALS AND METHODS

We performed a blinded analysis of radiographic data in 87 patients with 98 AFFs in all institutes in Yamagata prefectural area from 2009 to 2014. Among the 98 AFFs, 57 AFFs comprising 11 ST fractures in 9 patients and 46 DP fractures in 41 patients with adequate medical records and X-rays were surveyed for time to bone healing and geometry.

RESULTS

Of the 87 patients, 67 received BPs/denosumab (77%) and 10 received GCs (11%). Surgery was performed in 94 AFFs. Among 4 AFFs with conservative therapy, 3 required additional surgery. In univariate regression analyses for ST group versus DP group, male-to-female ratio was 2/7 versus 1/40, mean age at fracture was 58.2 (37-75) versus 78 (60-89) years, rheumatic diseases affected 55.5% (5/9) versus 4.9% (2/41), femoral lateral bowing angle was 1.7 (0-6) versus 11.8 (0.8-24)°, GC usage was 67% (6/9) versus 4.9% (2/41), and bone healing time was 12.1 (6-20) versus 8.1 (3-38) months (p < 0.05). In multivariate analyses, higher male-to-female ratio, younger age, greater proportion affected by rheumatic diseases, and higher GC usage remained significant (p < 0.05).

CONCLUSIONS

The incidence of AFFs in our prefectural area was 1.43 cases/100,000 persons/year. This study suggests that the onset of ST AFFs have greater correlation with the worse bone quality, vice versa, the onset of DP AFFs correlated with the bone geometry. The developmental mechanisms of AFFs may differ significantly between ST and DP fractures.

Acidity effects of medium fluids on anhydrous proton conductivity of acid-swollen block polymer electrolyte membranes

Proton-conductive polymer electrolyte membranes (PEMs) were prepared by infiltrating sulfuric acid (Sa) or phosphoric acid (Pa) into a polystyrene-b-poly(4-vinylpyridine)-b-polystyrene (S–P–S) triblock copolymer. When the molar ratio of acid to pyridyl groups in S–P–S, i.e., the acid doping level (ADL), is below unity, the P-block/acid phase in the PEMs exhibited a moderately high glass transition temperature (T_g) of ∼140 °C because of consumption of acids for forming the acid–base complexes between the pyridyl groups and the acids, also resulting in almost no free protons in the PEMs; therefore, the PEMs were totally glassy and exhibited almost no anhydrous conductivity. In contrast, when ADL is larger than unity, the T_gs of the phase composed of acid and P blocks were lower than room temperature, due to the excessive molar amount of acid serving as a plasticizer. Such swollen PEMs with excessive amounts of acid releasing free protons were soft and exhibited high conductivities even without humidification. In particular, an S–P–S/Sa membrane with ADL of 4.6 exhibited a very high anhydrous conductivity of 1.4 × 10⁻¹ S cm⁻¹ at 95 °C, which is comparable to that of humidified Nafion membranes. Furthermore, S–P–S/Sa membranes with lower T_gs exhibited higher conductivities than S–P–S/Pa membranes, whereas the temperature dependence of the conductivities for S–P–S/Pa is stronger than that for S–P–S/Sa, suggesting Pa with a lower acidity would not be effectively dissociated into a dihydrogen phosphate anion and a free proton in the PEMs at lower temperatures.

Sulfuric acid-swollen block polymer membranes exhibit anhydrous conductivities of ∼0.1 S cm⁻¹ that is higher than those of phosphoric acid-swollen membranes, whereas temperature dependence of conductivities of the latter is stronger than the former.

Highly Extensible Supramolecular Elastomers with Large Stress Generation Capability Originating from Multiple Hydrogen Bonds on the Long Soft Network Strands

Highly extensible supramolecular elastomers are prepared from ABA triblock-type copolymers bearing glassy end blocks and a long soft middle block with multiple hydrogen bonds. The copolymer used is polystyrene-b-[poly(butyl acrylate)-co-polyacrylamide]-b-polystyrene (S-Ba-S), which is synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. Tensile tests reveal that the breaking elongation (εb ) increases with an increase in the middle block molecular weight (Mmiddle ). Especially, the largest S-Ba-S with Mmiddle of 3140k, which is synthesized via high-pressure RAFT polymerization, achieves εb of over 2000% with a maximum tensile stress of 3.6 MPa, while the control sample without any middle block hydrogen bonds, polystyrene-b-poly(butyl acrylate)-b-polystyrene with Mmiddle of 2780k, is merely a viscous material due to the large volume fraction of soft block. Thus, incorporation of hydrogen bonds into the large molecular weight soft middle block is found to be beneficial to prepare supramolecular elastomers attaining high extensibility and sufficiently large stress generation ability simultaneously. This outcome is probably due to concerted combination of entropic changes and internal potential energy changes originating from the dissociation of multiple hydrogen bonds by elongation.

Fabrication and modification of ordered nanoporous structures from nanophase-separated block copolymer/metal salt hybrids

We report facile preparation of nanoporous thin films by rinsing out a metal salt from nanophase-separated hybrid films composed of a block copolymer and a water-soluble metal salt. Nanophase-separated hybrids were prepared by mixing polystyrene-b-poly(4-vinylpyridine) (PS-P4VP) and iron(III) chloride in a solvent of pyridine, followed by solvent-casting and thermal-annealing. Film samples with a thickness of ca. 100 nm were fabricated from the nanophase-separated hybrids by using a microtoming technique. Metal salts in the films were removed by immersion into water to fabricate nanopores. Morphological observations were conducted by using transmission electron microscopy (TEM). Ordered cylindrical nanopores were clearly observed in the thin films prepared from the water-immersed hybrids which originally present cylindrical nanodomains. These nanoporous films were modified by loading another metal salt, samarium(III) nitrate, into the nanopores on the basis of the coordination ability of P4VP tethered to the pore walls. The samples after loading treatment were evaluated by TEM observation and elemental analysis with energy dispersive X-ray spectroscopy.

Diblock-type supramacromolecule via biocomplementary hydrogen bonding

Control of nanostructure formation by a diblock-type supramacromolecule via biocomplementary hydrogen bonding has been achieved. Two different homopolymers, poly(4-trimethylsilylstyrene) and poly(styrene-d8), that are end-decorated with complementary oligonucleotides, i.e., thymidine phosphates and deoxyadenosine phosphates, were prepared by using the phosphoramidite method and blended successively. Association behavior in a blend solution was examined with NMR, and a cast bulk film obtained from the solution has been confirmed to show a nanophase-separated structure by transmission electron microscopy and X-ray scattering. Suppression of this nanostructure formation of a block-type supramacromolecule was also attained by adding a smaller agent as an inhibitor.

Nanophase-separated synchronizing structure with parallel double periodicity from an undecablock terpolymer

A new nanophase-separated structure with parallel double periodicity has been identified for an undecablock terpolymer in bulk. The polymer includes two long poly(2-vinypyridine) (P) chains on each end, with five short polyisoprene (I) and four short polystyrene (S) chains at the center. This polymer exhibits a hierarchical lamellar structure with two crystallographic periods: 88 nm and 16 nm. The 88 nm period includes one thick P lamella and five thin I-S-I-S-I lamellae, of extremely high orientation.

Novel synthesis and characterization of bioconjugate block copolymers having oligonucleotides

Novel and efficient synthesis of polymers terminated with nucleotides via the phosphoramidite method has been developed. A hydroxyl-terminated polymer was converted into a polymer capped with a nucleotide in three steps, where the conversion of the reactions was very high, almost 100%. By repetition of this synthetic method, a block copolymer composed of a synthetic polymer, polystyrene, and biological oligonucleotides with thymidine units has been successfully synthesized. A microphase-separated structure of this block copolymer was observed by both transmission electron microscopy and small-angle X-ray scattering, and a cylindrical structure was confirmed.

The effectiveness of the "Clean-Area-System" for infection control in the dental clinic

The use of effective infection control procedures and universal precautions in dental clinics, prevents cross contamination that could extend to dental health care workers and patients. The present study was initiated to investigate airborne environmental contamination in the dental clinic by viable cell count of oral streptococci grown on Mitis-Salivarius and blood agar plates. The reduction of the contamination by the "Clean-Area-System" was evaluated. "Andersen-Microbe-Sampler-Apparatus" and "Laser-Particle-Counter-System" were used for sampling and counting the bacterial cells and airborne dust, respectively. Numbers of viable cells counted as total colony forming units (CFUs) in the dental clinic were found to be significantly higher than those in the waiting room and the research laboratory. We found that the "Clean-Area-System" significantly reduced the CFUs grown on blood agar plates (p < 0.05), and that using the "Clean-Area-System" combined with the "Extra-Oral-Vacuum-Aspirator" is desirable in dental procedures such as cavity preparation. The "Extra-Oral-Vacuum-Aspirator" reduced airborne environmental contamination during tooth cutting and ultrasonic scaling procedures. In non-grinding procedures, this system proved to be very useful for infection control in the operative area. The authors concluded that the combined use of "Clean-Area-System" (dust collection ablation) and "Extra-Oral-Vacuum-Aspirator" (absorb dust ablation) was effective to reduce airborne environmental contamination in the dental clinic. We also fully confirmed that oral streptococci were an adequate indicator in the assessment for infection control in dental institutions.

Comparison of health and functional ability between noninstitutionalized and least dependent institutionalized elderly in Finland

Finland's active deinstitutionalization policy aims to reduce the number of elderly people in long-term residential care and to keep noninstitutionalized elderly people living at home as long as possible. As a contribution to the issue of the appropriateness of long-term institutional care, we compared the health and functional ability of elderly people living at home or in residential care to assess the theoretical possibility of discharging the least dependent elderly from residential homes. Findings from two separate data sets collected in 1992 were compared; one (n = 475) was obtained by computer-assisted telephone interview (elderly at home) and the other (n = 459) by postal survey (elderly in residential care). The direct method was used in age and gender standardization, and logistic regression analysis was applied. Elderly people living at home were found to be in better health and with better functional ability than those in residential care. However, a proportion of home-dwellers needing some help with Activities of Daily Living (ADLs) assessed their health as being even worse than those in care, and approximated that of institutionalized elderly judged by the personnel to be able to manage with home-based care. Compared with home-dwellers, those assessed as able to manage in-home care were mostly single and had less education and more restrictions in their Instrumental ADLs and medication. Our results indicate that one third of those assessed as able to manage in-home care could possibly be discharged if adequate servicers and housing were available.

Deinstitutionalization of the elderly in Finland, 1981-91

The success of Finnish deinstitutionalization policy among the elderly in 1981-1991 was evaluated in terms of institutionalization rates and case-mix. Censuses of institutionalized people in all public and private residential homes and health centre hospitals (or nursing homes) were performed in 1981, 1986 and 1991. Data on demographic factors, diagnoses and dependency level were gathered. Censuses from the closest years of psychiatric patients were also used to obtain a comprehensive view of institutionalization. The eligibility criteria for the study were (1) age 65 years or more (2) currently in long-term care. In both men and women the overall relative reduction was 33%, and largest in psychiatric care, at over 67%. In residential home care the relative reduction was about 40%. In health centre hospitals a slight increase was seen, about 10%. Length of stay shortened in residential homes but increased in health centre wards. Dependency level increased among the elderly people in long-term institutional care during ten years. In conclusion, the deinstitutionalization rate was substantial among the elderly in Finland. However, because of rapid demographic change the absolute number of elderly in long-term care remained almost constant. The case-mix has become more demanding and the proportion of elderly in constant need of extensive help has risen.