Switching of Slow Magnetic Relaxation Dynamics in Mononuclear Dysprosium(III) Compounds with Charge Density.

The symmetry around a Dy ion is recognized to be a crucial parameter dictating magnetization relaxation dynamics. We prepared two similar square-antiprismatic complexes, [Dy(LOMe)2(H2O)2](PF6) (1) and Dy(LOMe)2(NO3) (2), where LOMe = [CpCo{P(O)(O(CH3))2}3], including either two neutral water molecules (1) or an anionic nitrate ligand (2). We demonstrated that in this case relaxation dynamics is dramatically affected by the introduction of a charged ligand, stabilizing the easy axis of magnetization along the nitrate direction. We also showed that the application of either a direct-current field or chemical dilution effectively stops quantum tunneling in the ground state of 2, thereby increasing the relaxation time by over 3 orders of magnitude at 3.5 K.

Synthesis, crystal structures, and magnetic properties of cyanide-bridged W(V)Mn(III) anionic coordination polymers containing divalent cationic moieties: slow magnetic relaxations and spin crossover phenomenon.

Two trimetallic coordination complexes were prepared by self-assembly of [W(CN)8](3-) and the Mn(III) Schiff base followed by the addition of a Zn(II) or Fe(II) cationic unit. The octacyanotungstate connects neighboring Mn(III) centers to form a one-dimensional chain. The anionic chain requires cationic units of Zn(II) or Fe(II) to maintain charge balance in the structure. The Zn-containing complex shows ferrimagnetic behavior originating from the antiparallel alignment of W(V) and Mn(III) spins within the chain, which leads to slow magnetic relaxation at low temperatures. For the Fe(II)-containing compound, Fe(II) moieties are integrated into the ferrimagnetic chains, altering their spin states depending on the temperature. It appears that the coexistence of high- and low-spin states in the low temperature regime is responsible for the slower and faster relaxations of the magnetization.

Synthesis, structures, and magnetic properties of end-to-end azide-bridged manganese(III) chains: elucidation of direct magnetostructural correlation.

The two one-dimensional chain compounds [Mn(L1)(N3)]·H2O (1·H2O; H2L1 = 2,2'-((1E,1'E)-ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(phenylmethan-1-yl-1-ylidene)diphenol) and [Mn(L2)(N3)] (2; H2L2 = 2,2'-((1E,1'E)-2,2-dimethylpropane-1,3-diyl)bis(azan-1-yl-1-ylidene)-bis(phenylmethan-1-yl-1-ylidene)diphenol) bridged by single end-to-end azides were prepared via a self-assembly process. Each Mn(III) ion exhibits a characteristic Jahn-Teller elongation along the chain direction. For both compounds, antiferromagnetic interactions between Mn(III) spins within a chain are transmitted through the azide ligands, together with the apparent occurrence of spin canting at low temperatures. Remarkably, the coupling constants (J) for 1 and 2 exceed those reported for end-to-end azide-linked Mn(III) systems. A systematic magnetostructural relationship based on the torsion angle is established in terms of the torsion angle Mn-N(ax)···N(ax)-Mn (ax = axial) for the first time.

Cyanide-bridged W(V)Mn(III) bimetallic chains composed of a blocked W hexacyanide precursor: geometry-related magnetic couplings and magnetostructural correlation.

Five one-dimensional bimetallic W(V)Mn(III) complexes 1-5, consisting of [W(CN)6(bpy)](-) anions and [Mn(Schiff base)](+) cations, were prepared. The central coordination geometry around each W atom is determined as a distorted dodecahedron (DD) for 1 and 2, and a distorted square antiprism (SAPR) for 3-5. Magnetic analyses demonstrate that compounds 1, 4, and 5 exhibit antiferromagnetic interactions between magnetic centers, which are different from the ferromagnetic couplings in 2 and 3. For the distorted DD geometry, the Mn-N(ax) (ax = axial) bond length increases when moving from 1 to 2, with the Mn-N(ax)-C(ax) angle remaining constant. The elongation of the bond length is responsible for the reduction in orbital overlap and consequent ferromagnetic coupling in 2. In comparison, for 3-5 with the distorted SAPR geometry, given that the Mn-N(ax) bond lengths are similar across all the samples, the increase in the Mn-N(ax)-C(ax) angles accounts for the enhanced magnetic strength. Notably, a correlation between structure and magnetic exchange coupling is established for the first time in W(V)Mn(III) bimetallic systems based on the [W(CN)6(bpy)](-) precursor.

Peak Net Pressure Coefficients of Elliptical Center-Open Dome Roofs.

Recently, the demand for spatial structures such as retractable dome roofs is increasing. The safety of dome roofs must be ensured even when they are open. Hence, studies analyzing the peak pressure coefficients of spherical dome roofs are actively being conducted. However, no peak pressure coefficients for the cladding design of elliptical retractable dome roofs have been proposed. Although several studies on elliptical open dome roofs that open from the edge to the center have been conducted, studies on those that open from the center to the edge are still insufficient. This study investigated the peak pressure coefficients of elliptical center-open dome roofs. For wind tunnel tests, a model was fabricated with an opening ratio of 30%. Under experimental conditions, five different wall height-to-span ratios (from 0.1 to 0.5) were used, with the roof rise-to-span ratio set at 0.1. Accordingly, the experimental values of the peak pressure coefficients of elliptical center-open dome roofs were compared with those of the closed dome roofs proposed in the Korean and Japanese wind load codes. Subsequently, their efficiency was verified. The findings were also compared with previous research outcomes. Based on the results, peak net pressure coefficients are proposed for cladding designs suitable for elliptical center-open dome roofs.

One-dimensional end-to-end azide-bridged Mn(III) complexes incorporating alkali metal ions: slow magnetic relaxations and metamagnetism.

Three azide-bridged Mn(III) chains [Mn(3-MeOsalpn)(N(3))]⋅0.5 AClO(4) (A = Na (1), K (2), Rb (3); 3-MeOsalpn = N,N'-propylenebis(3-methoxysalicylideneiminato) dianion) incorporating alkali metal ions and perchlorate anions were systematically synthesized. The overall structure can be described as a one-dimensional chain bridged by end-to-end azide ligands, although spatial arrangements of Jahn-Teller axes of Mn in 1 and 2 are different from that in 3. Relying on the alkali metal ions, magnetic properties are varied from a two-step phase transition (1) to metamagnetic transitions (2 and 3). In this system, spin canting definitely plays a central role in giving rise to the apparent slow magnetic relaxations in 1 and 2 because application of a high external magnetic field tends to destroy single-chain magnet (SCM) properties. Despite the existence of a long-range antiferromagnetic order at T(N) , slow magnetic relaxation is notably observed in 2, which likely emanates from the operative spin canting below T(N) .

End-to-end azide-bridged manganese(III) chain compounds: field-induced magnetic phase transitions and variation of T(C) to 38 K depending on the side groups of the Schiff bases.

Three one-dimensional coordination polymers [Mn(L)(N(3))](n) [L = L1 (1), L2 (2), L3 (3); L1H(2) = N,N'-bis(5-chlorosalicylideneiminato)-1,3-diaminopentane, L2H(2) = N,N'-bis(5-bromosalicylideneiminato)-1,3-diaminopentane, L3H(2) = N,N'-bis(5-bromosalicylideneiminato)-1,3-diamino-2-dimethylpropane] bridged by end-to-end azides were prepared. The crystal systems differ according to the Schiff bases used. Each Mn atom adopts a typical Jahn-Teller distortion. The helicity of the chains occurs in a racemic manner only for 2. No noncovalent forces are relevant in 2, while π-π contacts are visible in 1 and 3. Magnetic measurements show the presence of apparent spin canting. Complexes 1 and 3 exhibit a field-induced metamagnetic transition from an antiferromagnetic state to a weak ferromagnetic phase, whereas 2 embraces a field-induced two-step magnetic phase transition. The critical temperature is observed at 38 K for 2, which is relatively higher than those for 1 (11 K) and 3 (10 K). The pronounced long-range order may contribute from intrachain exchange couplings and through-space dipolar interactions between adjacent chains.

Cyanide-bridged W(V)Mn(III) single-chain magnet with isolated Mn(III) moieties exhibiting two types of relaxation dynamics.

A 5d-3d bimetallic compound was prepared by self-assembling [W(CN)(8)](3-) and the Mn(III) Schiff bases. This neutral complex consists of cyanide-linked W(V)Mn(III) anionic chains and isolated Mn(III) Schiff base cations. We demonstrate that two types of relaxation processes are involved in the system; the low-T dynamics may come from magnetic domain dynamics and the high-T relaxation stems from the anionic chain, revealing single-chain magnet character.

Experimental Investigation of Wind Pressure Characteristics for Cladding of Dome Roofs.

Cladding for dome roofs is often made of membrane materials that are light and easy to install. Due to these characteristics, wind damage to dome roof cladding is very common. In particular, open or retractable dome roofs are prone to wind damage because of inadequacies in wind load calculations. In this study, the wind pressure characteristics of a dome with a central opening were investigated. Wind tunnel tests were performed, and the pressure distribution was investigated by analyzing external and internal pressure coefficients. Based on the experimental results, the peak net pressure coefficients for the cladding design of a dome roof with a central opening were proposed. For the external peak pressure coefficients, the values of leeward regions were similar despite height-span ratios and turbulence intensity values. For the internal peak pressure coefficients, negative pressure was dominant, and the coefficients were not significantly affected by changes in height-span ratio. This tendency locally increased the negative peak net pressure, in which the load acts in the upward direction, and relatively significantly increased the positive peak net pressure, in which the load acts in the downward direction.

Floor Vibration Experiment and Serviceability Test of iFLASH System.

Studies on novel composite structures that can decrease floor height and improve constructional efficiency in order to increase spatial efficiency and lease revenue have been actively conducted. An innovative fire-proof, lightweight, absorbed, shallow, and hybrid (iFLASH) system was developed to solve construction site issues, such as improving constructability, reducing construction time, and attaining structural efficiency by reducing the weight of the building structure. This system can shorten the construction duration and decrease the floor height and structural weight, owing to features such as a low thickness and light weight. However, studies on the vibration characteristics of this new floor system have not been performed yet. As the general thickness of the iFLASH system ranges from 25 to 30 mm, it must have a sufficient floor vibration performance in order to be utilized. To evaluate the floor vibration performance of the iFLASH system, an experiment was performed in two buildings where the system was applied. This paper presents the results of the dynamic characteristics and serviceability testing as basic data for the vibration characteristics of the iFLASH system.

An end-on azide-bridged antiferromagnetic single-chain magnet involving spin canting and field-induced two-step magnetic transitions.

Two-step magnetic transitions: An azide-bridged 1D Mn(III) coordination polymer with a unique single end-on mode was prepared; it displayed atypical antiferromagnetic couplings and field-induced two-step magnetic transitions (see figure). The spin-canted phenomenon in the antiferromagnetic chain complex plays a pivotal role in establishing the slow magnetic relaxation.

Cyanide-bridged one-dimensional ferromagnetic Ru(III)Mn(III) coordination polymer exhibiting a field-induced magnetic phase transition.

A cyanide-linked Ru(III)(4d)-Mn(III)(3d) bimetallic chain complex (1) was prepared by the self-assembly of a ruthenium(III) bicyanide and a Mn(III) Schiff base. Ferromagnetic couplings between the magnetic centers are present within a chain, while antiferromagnetic interactions between chains (T(N) = 2.5 K) transmit. Complex 1 also shows a field-induced magnetic phase transition.

Preparation of diisononyl adipate in a solvent-free system via an immobilized lipase-catalyzed esterification.

Diisononyl adipate is a plasticizer which has excellent property of low temperature resistance and is permitted in food contact materials. In this study, diisononyl adipate was synthesized from adipic acid and isononyl alcohol in a solvent-free system via immobilized lipase-catalyzed esterification. Liquid Eversa lipase from Thermomyces lanuginosus was immobilized on Lewatit VP OC 1600 carrier. The effects of temperature, substrate molar ratio, water activity of enzyme, vacuum, and enzyme loading on the reaction efficiency were investigated. Application of vacuum played a key role to achieve a 100% conversion. The optimal temperature, molar ratio (adipic acid to isononyl alcohol), water activity of enzyme, vacuum were 50 °C, 1:3, 0.75, 13.3 kPa, and 10% (based on weight of total substrate). Under these conditions, 100% conversion was achieved within 6 h.

A study on a non-contacting respiration signal monitoring system using Doppler ultrasound.

We proposed non-contacting respiration signal monitoring system for sleep apnea syndrome. Experiments were conducted by emitting 40 kHz ultrasound beam, which is set tone burst mode by 1 ms period to a subject chest. Normal respiration condition and a simulated sleep apnea syndrome condition were measured while subjects were holding breath. To obtain the actual respiration signal from the raw signal, ultrasound attenuation characteristics were considered. The Doppler ultrasound signal was detectable once the received signal obtained by demodulation circuits passed through a low pass filter (LPF). The signal's ripples were eliminated by moving average method and the signal's peaks were detected by phase portrait reconstruction method to measure the respiration rate.

Effect of foot orthoses on children with lower extremity growing pains.

OBJECTIVE: To evaluate the effect of custom molded foot orthoses on children with growing pains of the lower extremities. METHODS: Children with growing pains were recruited during a clinic visit. None had any bony deformities, inflammatory joint disease or depression. Resting calcaneal stance position (RCSP) and calcaneal pitch angle were measured, and individual custom molded rigid foot orthoses were prescribed using the inverted orthotic technique to control for foot overpronation using the RCSP angle. Pain sites, degree and frequency of pain, and balance ability were evaluated using Balance Master computerized posturography prior to foot orthosis fitting, and 1 and 3 months later. RESULTS: Twenty children completed the study. Seventeen (75%) had overpronated feet. Significant improvements were noted after 1 and 3 months in pain degree and frequency, and after 3 months in balancing ability. CONCLUSION: The use of custom molded foot orthoses is a good method for treating children with multiple musculoskeletal pains in the leg.

Effect of Custom-Molded Foot Orthoses on Foot Pain and Balance in Children With Symptomatic Flexible Flat Feet.

OBJECTIVE: To evaluate the effect of custom-molded foot orthoses on foot pain and balance in children with symptomatic flexible flat foot 1 month and 3 months after fitting foot orthosis. METHOD: A total of 24 children over 6 years old with flexible flat feet and foot pain for at least 6 months were recruited for this study. Their resting calcaneal stance position and calcaneal pitch angle were measured. Individual custom-molded rigid foot orthoses were prescribed using inverted orthotic technique to control foot overpronation. Pain questionnaire was used to obtain pain sites, degree, and frequency. Balancing ability was determined using computerized posturography. These evaluations were performed prior to custom-molded foot orthoses, 1 month, and 3 months after fitting foot orthoses. RESULT: Of 24 children with symptomatic flexible flat feet recruited for this study, 20 completed the study. Significant (p<0.001) improvements in pain degree and frequency were noted after 1 and 3 months of custom-molded foot orthoses. In addition, significant (p<0.05) improvement in balancing ability was found after 3 months of custom-molded foot orthoses. CONCLUSION: Short-term use of custom-molded foot orthoses significantly improved foot pain and balancing ability in children with symptomatic flexible flat foot.

Changes in lipid substances in rice during grain development.

Lipid substances, such as fatty acids, γ-oryzanol, policosanols, and tocol (tocopherol+tocotrienol), were investigated in two rice cultivars, Ilpum and Dasan, during rice development. In both cultivars, the lipid extract level decreased steadily after it reached its maximum level. Additionally, there were differences in the fatty acid composition, depending on the rice developmental stage, between the two cultivars. The γ-oryzanol level increased during rice development, and there were differences in the composition of γ-oryzanol between the two cultivars. The levels of policosanols drastically decreased during the early stage of rice development in the two cultivars. The total tocol level showed a downward trend during rice development. The predominant tocol isomer in Ilpum was α-tocopherol during rice development. In Dasan, the predominant tocol isomer was α-tocopherol at the early stage, but γ-tocotrienol at the later stage. This study provided information on the levels and composition of lipid substances, such as fatty acids, γ-oryzanol, policosanols, and tocol during rice development.

[Current state of influenza vaccination and factors affecting vaccination rate among pregnant women].

PURPOSE: This study was done to examine the actual state of influenza vaccination among pregnant women and factors affecting vaccination rate. METHODS: Data were collected using self-report questionnaires. Participants were pregnant women who participated in a prenatal education program at an acute care hospital in 2013. Data collected from 218 pregnant women were analyzed using the SPSS 18.0 Program. RESULTS: Only 48.6% of the pregnant women had received vaccination when the influenza was prevalent. Statistically significant factors affecting the influenza vaccination rate among pregnant women were vaccination experience in the previous year, knowledge and attitude about vaccination, and gestation period. CONCLUSION: Results indicate that the influenza vaccination rate among pregnant women is lower than that of elders, healthcare workers, and patients with chronic diseases, who have been considered to be the mandatory vaccination recipients. Therefore, it is necessary to develop programs and policies which provide information including safety of vaccines for pregnant women and to induce positive attitudes towards vaccination for these women, in order to ultimately improve the vaccination rate.

A case of acute bilateral retrocochlear hearing loss as an initial symptom of unilateral thalamic hemorrhage.

A speech discrimination test is a test using a list of 25 phonetically balanced monosyllables. It is often overlooked but significant enough for pure tone audiometry. Many physicians have performed pure tone audiometry but without a speech discrimination test. A 73-year-old woman visited our clinic complaining of sudden bilateral hearing loss. Pure tone audiometry showed only bilateral high frequency loss. However, speech discrimination had decreased markedly. We decided to follow-up after 1 week of Ginexin-F® (ginkgo leaf extract) and Nafril® (nafronyl oxalate). She felt a gait disturbance within 2 days. Magnetic resonance imaging revealed a left thalamic hemorrhage. After a 1 month hospitalization, the hematoma subsided, and speech discrimination recovered 3 months later. Acute hearing loss due to thalamic hemorrhage that recovered has never been reported. We report the first case of retrocochlear hearing loss that occurred with a thalamic hemorrhage in a patient who recovered.

Concentrations of tocols and γ-oryzanol compounds in rice bran oil obtained by fractional extraction with supercritical carbon dioxide.

Rice bran oil (RBO) is a good source of several commercially important bioactive phytochemicals, such as tocols (i.e. tocopherols and tocotrienols) and ferulic esters of sterols (i.e. γ-oryzanol). The aims of the present study were to examine the effects of different pressure and temperature combinations on the fractional extraction of RBO using supercritical carbon dioxide (SC-CO2) and to assess the levels of tocols homologues and γ-oryzanol components in the resulting oil fractions. Fractional extraction of rice bran oil was performed using SC-CO2 at either 27.6 or 41.4 MPa and either 40 or 60°C. The effects of the four different pressure and temperature combinations on the levels of seven tocols homologues (α-, ß-, γ- and δ-tocopherol and α-, γ- and δ-tocotrienol) and the four major components of γ-oryzanol in the resulting oil fractions were investigated. Superior extraction efficiency was obtained using the higher pressure of 41.4 MPa. The tocols (particularly α-tocopherol and α-tocotrienol) were recovered early in the extraction process, while the γ-oryzanol compounds were obtained in the later stages. With regard to SC-CO2 extraction, tocols are more soluble than γ-oryzanol components, α-tocopherol is the most soluble of the tocols and the four γ-oryzanol components all have similar solubilities. Valuable data on solubilities of tocols homologues in SC-CO2 were provided from present study.