Size-Controlled Preparation of Polyethylene Nanoplastic Particles by Nanoprecipitation and Insights into the Underlying Mechanisms.

Plastic pollution is ubiquitous in the environment, and nanoplastics (<1 µm) are of growing concern as they pose more health risks than larger particles. However, because of a lack of appropriate model particles, studies examining the risks of polyolefin nanoplastics are very limited, despite the prevalence of these plastics in the environment. Although nanoprecipitation using organic solvents is a promising method for preparing model nanoplastic particles of polyolefins, there are currently no methods for controlling the particle size. Here, we examined how the concentration and volume of the feedstock polymer solution affect the size of polyethylene particles produced by nanoprecipitation. The mechanisms underlying the particle formation were investigated by using a simple population balance model. Increasing the concentration of the feedstock solution increased the growth rate and decreased the nucleation rate, and increasing the volume of the feedstock solution increased the growth rate, resulting in an increase in the mean particle diameter in both cases. These changes in particle diameter were linearly correlated with the suspension density of the dispersion up to a suspension density of 0.4 mg·mL-1. In addition, at these suspension densities, spherical particles were prepared without generating aggregates. Together, these results show that the diameter of polyethylene particles prepared by nanoprecipitation could be controlled according to the suspension density up to a suspension density of 0.4 mg·mL-1. This study provides a basis for the development of nanoprecipitation-based techniques for the precise, scale-independent production of model nanoplastic particles, which we hope will accelerate the risk assessment of nanoplastics.

Pressure-induced evolution in the durability of nickel-metal hydride batteries under high-current charge.

We found that an AAA-type battery (min. 750 mAh) pressurized with Ar or N2 at pressures of up to 5 MPa exhibited a significant durability enhancement even under high-current conditions. As an example of a charge-discharge cycle test at 3 amperes, the residual ratio of capacity at atmospheric pressure decreased to approximately 90% of the standard capacity before 50 cycles. However, at a pressure of 3 MPa of N2, the capacity remained at more than 90% until 180 cycles. With an increase in the pressure, the residual ratio of capacity was further improved. It has been considered that, at the positive electrode of the Ni-MH battery, the chemical reaction from nickel(II) hydroxide (Ni(OH)2) crystals to nickel oxide hydroxide (NiOOH) crystals occurs during the charging process. However, X-ray diffraction (XRD) results in the present study do not support this solid-solid reaction between these two types of crystal. To address this contradiction, we propose a different reaction mechanism by introducing the concept of non-crystalline fine particles of compounds, which are undetected by XRD. This mechanism clearly explains how the pressure affects the durability improvement. Pressurized batteries, which are capable of fast charge-discharge operation under high-current conditions, can provide a new route for application fields of unconventional energy storage.

Kinetic Modelling of Electroless Nickel-Phosphorus Plating under High Pressure.

In electroless nickel-phosphorus plating (ENPP), growth of the plated layer under high pressure was found to be faster than under ambient pressure. To quantitatively elucidate the effect of high pressure on the mechanism of the ENPP reaction, we propose a kinetic model that takes into account both mass transfer and reaction of the chemical species present in the plating solution. We solved the mass balance equations between the chemical species to calculate the transient changes in the thickness of the plated layer as well as the concentrations of the chemical species in the plating solution. By fitting the calculated results to the experimentally acquired results based on the nonlinear least square method, we determined such parameters as the film mass transfer coefficient, the adsorption constants, and the reaction rate constants of the chemical species in the model. As a result, we found that the film mass transfer coefficient under high pressure was greater than that under ambient pressure and revealed the dependence of the coefficient on pressure. The transient changes in the concentrations of the chemical species in the plating solution that we calculated based on the kinetic model employing our estimated parameters closely modeled the experimental results with the determination coefficients being mostly over 99%.

Simple solvatochromic spectroscopic quantification of long-chain fatty acids for biological toxicity assay in biogas plants.

Oily organic waste is a promising feedstock for anaerobic co-digestion. Free long-chain fatty acids (LCFAs) produced from lipids can inhibit methanogenic consortia, so optimal control of LCFA concentration is the key to successful operation of co-digestion. Most LCFAs are present in the solid phase, making them difficult to be detected and monitored. This study proposes a simple and easy method for detecting LCFAs in both the liquid and solid phases of anaerobic digestate by combining liquid-liquid extraction followed by solid-phase extraction (SPE) and spectrophotometric analysis. The extraction procedure successfully removed impurities that interfere with the absorbance spectrum and ensured high recovery rates of LCFAs. The utility of the pretreatment used for the extraction was discussed using thermodynamic analysis and calculations of phase equilibrium for the solvent extraction system. The absorbance spectrum shift of pyridinium N-phenolate betaine (PNPB) dye-stained solution showed a good correlation with LCFA concentration and enabled highly sensitive measurements. Good quantification was demonstrated in experiments using various digestate samples obtained from the laboratory, pilot, and full-scale reactors.

Dual-fuel production from restaurant grease trap waste: bio-fuel oil extraction and anaerobic methane production from the post-extracted residue.

An effective way for restaurant grease trap waste (GTW) treatment to generate fuel oil and methane by the combination of physiological and biological processes was investigated. The heat-driven extraction could provide a high purity oil equivalent to an A-grade fuel oil of Japanese industrial standard with 81-93 wt% of extraction efficiency. A post-extracted residue was treated as an anaerobic digestion feedstock, and however, an inhibitory effect of long chain fatty acid (LCFA) was still a barrier for high-rate digestion. From the semi-continuous experiment fed with the residual sludge as a single substrate, it can be concluded that the continuous addition of calcium into the reactor contributed to reducing LCFA inhibition, resulting in the long-term stable operation over one year. Furthermore, the anaerobic reactor performed well with 70-80% of COD reduction and methane productivity under an organic loading rate up to 5.3g-COD/L/d.

Fast charging of lead-acid batteries enabled by high-pressure crystallization.

Lead-acid batteries were electrically charged and discharged more quickly under high pressures than under atmospheric pressure due to high-pressure crystallization induced by the former condition. High-pressure crystallization can generate extremely small crystals with large supersaturation and small mass transfer rates. Crystals of PbSO4 on the electrodes were observed by scanning electron microscopy, and the crystals became smaller when the operative pressure increased, even when faster charging was carried out. Additionally, the amount of electrical current transferred to the electrodes was larger for electrodes charged and discharged at high pressure. This high-pressure charge-discharge process is expected to improve the quality of lead-acid batteries.

The TRK-fused gene is mutated in hereditary motor and sensory neuropathy with proximal dominant involvement.

Hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P) is an autosomal-dominant neurodegenerative disorder characterized by widespread fasciculations, proximal-predominant muscle weakness, and atrophy followed by distal sensory involvement. To date, large families affected by HMSN-P have been reported from two different regions in Japan. Linkage and haplotype analyses of two previously reported families and two new families with the use of high-density SNP arrays further defined the minimum candidate region of 3.3 Mb in chromosomal region 3q12. Exome sequencing showed an identical c.854C>T (p.Pro285Leu) mutation in the TRK-fused gene (TFG) in the four families. Detailed haplotype analysis suggested two independent origins of the mutation. Pathological studies of an autopsied patient revealed TFG- and ubiquitin-immunopositive cytoplasmic inclusions in the spinal and cortical motor neurons. Fragmentation of the Golgi apparatus, a frequent finding in amyotrophic lateral sclerosis, was also observed in the motor neurons with inclusion bodies. Moreover, TAR DNA-binding protein 43 kDa (TDP-43)-positive cytoplasmic inclusions were also demonstrated. In cultured cells expressing mutant TFG, cytoplasmic aggregation of TDP-43 was demonstrated. These findings indicate that formation of TFG-containing cytoplasmic inclusions and concomitant mislocalization of TDP-43 underlie motor neuron degeneration in HMSN-P. Pathological overlap of proteinopathies involving TFG and TDP-43 highlights a new pathway leading to motor neuron degeneration.

Bovine viral diarrhea virus 2 infection activates the unfolded protein response in MDBK cells, leading to apoptosis.

Bovine viral diarrhea virus 2 (BVDV-2) strains are divided into cytopathic and non-cytopathic biotypes based on the ablity to induce cytopathic effects in cultured cells. The mechanism of cytopathogenicity of BVDV-2 is not well understood. We examined cytopathogenesis in MDBK cells resulting from BVDV-2 infections by microscopic examinations and microarray analysis. We found that BVDV-2 activates endoplasmic reticulum (ER) stress signaling pathways that contribute to apoptosis of infected cells. We also monitored the expression of ER stress marker gene by RT-PCR during BVDV-2 infection and demonstrated that infection of MDBK cells with a cytopathic strain of BVDV-2 induces glucose-regulated protein 78 expression. Infection with BVDV-2 also induces DNA-damage-inducible transcript 3 expression and downregulates the lectin-galactoside-binding soluble 1 level. These results show that cytopathic strains of BVDV-2 induce an ER stress response resulting in apoptosis.

Effects of chelating reagents on colonial appearance of Paenibacillus alvei isolated from canine oral cavity.

A bacterial strain isolated from the oral cavity of a healthy dog revealed an unusual colony formation in nebular appearance on agar plates. The isolated bacterial strain was Gram-positive, spore-forming rod with peritrichous flagella, and grown under aerobic conditions, but unable to grow at 45 degrees C. The strain was tentatively classified as Paenibacillus alvei according to the biochemical properties and the 16S rRNA gene sequence. The isolate exhibits collective locomotion on solid agar plates. The bacterial motility was inhibited with EDTA and was restored by adding magnesium. We concluded that magnesium ion is essential for collective locomotion of P. alvei. This suggests that EDTA is useful for inhibition of biofilm formation.

Coronary plaque stabilization followed by Color Code Plaque analysis with 64-slice multidetector row computed tomography.

A 61-year-old woman with hypercholesterolemia, hypertension and diabetes mellitus was referred to hospital for the evaluation of chest pain at rest. Eccentric 50% stenosis in the proximal right coronary artery was detected by 64-slice multidetector row computed tomography (MDCT). The plaque morphology was considered as soft by Color Code Plaque (CCP) analysis. Seven days after MDCT, chest pain continued and transient ST-elevation was detected on the II-lead ECG monitor during echocardiography. Therefore, emergency coronary angiography was performed and confirmed the 50% stenosis as shown on MDCT. Her disease was diagnosed as vasospastic angina. For the purpose of plaque stabilization, lipid-lowering therapy with atorvastatin was instituted and her symptoms improved. After 11 months, serum total cholesterol and LDL-cholesterol levels were reduced. A second MDCT was performed and plaque morphology had changed from soft to intermediate. Cross-sectional multiplanar reconstruction of MDCT images indicated reduction of total vessel area, expansion of the lumen area and improvement of the remodeling index at the site of stenosis. The lipid-lowering therapy contributed to plaque stabilization, and CCP analysis by noninvasive MDCT was useful for plaque characterization. This case suggests that differences between vulnerable and stable plaques can be classified using MDCT to predict acute coronary syndrome.

Determination of physicochemical properties of tetrabromobisphenol A.

Aqueous solubility (Sw), 1-octanol/water partition coefficient (Kow), and vapor pressure of the nonionic form of 2,2',6,6'-tetrabromo-4,4'-isopropylidenediphenol (tetrabromobisphenol A or TBBP-A) were measured. From this, enthalpies of solution and vaporization were estimated. Furthermore, enthalpy of fusion and melting point were measured to estimate subcooled liquid vapor pressure, the infinite dilution activity coefficient, and Henry's law constant. Since TBBP-A is expected to exit in both ionic and nonionic forms at near neutral pH, pH effects on physicochemical properties were also examined. Because of the ionization of TBBP-A, Sw increased by five orders of magnitude, while Kow decreased by eight orders of magnitude. Furthermore, an analytical model based on mass balance and dissociation of TBBP-A was applied to represent the pH dependence.

New concept of solute distribution around a diffusive crystal-solution interface of a binary Lennard-Jones mixture from the viewpoint of molecular dynamics.

Directional crystallization from a binary mixture was performed by pseudo-NpT ensemble molecular dynamics. The initial crystal phase having a face-centered-cubic (fcc) structure grew toward the whole cell according to the temperature gradient in the universal cell. The growing crystal phase was not planar even though the solute molecules grew in two-dimensional coordinates because the solvent molecules disturbed the crystallization of the solute molecules at the diffusive crystal-solution interface. This represented the essential phenomenon of solute distribution during crystallization. Consequently, the growing crystal phase still contained solvent molecules having a liquid structure. The time change of the solute composition in the early phase of crystal growth showed an increase in solute composition as the time step proceeded. The resulting solute composition in this early phase was considered at different temperature gradients in the universal cell and it increased as the temperature of the initial crystal-solution interface increased. A new distribution coefficient model was proposed as a function of the difference between the local solute composition and bulk solute composition in the solution around the crystal-solution interface. The impurity-solvent distribution coefficient could be represented by the new model for faster growth of the lower temperature's initial interface. As regards a better distribution coefficient, there was found to be a very dilute solution phase over the crystal phase. The new variable "distribution rate" instead of the ambiguous variable "growth rate" was considered as a function of temperature gradient in the universal cell.

Refinement of a locus for autosomal dominant hereditary motor and sensory neuropathy with proximal dominancy (HMSN-P) and genetic heterogeneity.

Hereditary motor and sensory neuropathy with proximal dominancy (HMSN-P) is an adult-onset peripheral neurodegenerative disorder which has been reported only in the Okinawa Islands, Japan. The disease locus of "Okinawa-type" HMSN-P has been previously mapped to 3q13.1, with all affected individuals sharing an identical haplotype around the locus, suggesting that the undiscovered causative mutation in HMSN-P originated from a single founder. We have newly found two large families from the western part of Japan within which multiple members developed symptoms similar to those exhibited by HMSN-P patients from Okinawa, with no record of affinal connection between the islands. Using these pedigrees with "Kansai-type" HMSN-P, we carried out a linkage study utilizing eight microsatellite markers and identified a candidate region on 3q13.1 cosegregating with the disease (maximum two-point LOD score of 8.44 at theta=0.0) overlapping with the Okinawa-type HMSN-P locus. However, the disease haplotype shared among all affected members in these families was different from that in the Okinawa kindred, suggesting allelic heterogeneity. Such allelic variation should aid in the identification of the disease-causative gene. Moreover, the allelic heterogeneity of HMSN-P in the Japanese population suggests that HMSN-P may be more common across other ethnic groups, but classified into other disease categories.

Physicochemical properties of selected polybrominated diphenyl ethers and extension of the UNIFAC model to brominated aromatic compounds.

The aqueous solubilities (S(w)) at various temperatures from 283 K to 308 K and 1-octanol/water partition coefficients (K(ow)) for four polybrominated diphenyl ethers (PBDEs: 4,4'-dibromodiphenyl ether (BDE-15), 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentabromodiphenyl ether (BDE-99), and 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153)) were measured by the generator column method. The S(w) and K(ow) data revealed the effect of bromine substitution and basic structure on S(w) and K(ow). To estimate the infinite dilution activity coefficients (gamma(i)(w,infinity)) of the PBDEs in water from the S(w) data, enthalpies of fusion and melting points for those compounds were measured with a differential scanning calorimeter. Henry's Law constants (H(w)) of the PBDEs were derived from the determined gamma(i)(w,infinity) and literature vapor pressure data. Some physicochemical characteristics of PBDEs were also suggested by comparing the present property data with that of polychlorinated dibenzo-p-dioxins, brominated phenols and brominated benzenes in past studies. Furthermore, in order to represent different phase equilibria including solubility and partition equilibrium for other brominated aromatic compounds using the UNIFAC model, a pair of UNIFAC group interaction parameters between the bromine and water group were determined from the S(w) and K(ow) data of PBDEs and brominated benzenes. The ability of the determined parameters to represent both properties of brominated aromatics was evaluated.

Noninvasive assessment of coronary stents in patients by 16-slice computed tomography.

BACKGROUND: The usefulness of thin-slice multi-detector computed tomography (MDCT) has been highly expected to assess the lumens of coronary artery stents. We evaluated the usefulness of 16-slice MDCT to assess the in-stent lumen after coronary artery stenting. METHODS: In 42 consecutive patients after coronary artery stenting, retrospective ECG-gated CT-angiography using 16-slice MDCT (0.5-s rotation time, 16x0.625-mm detector collimation) was performed. The qualitative assessability of the lumens of 61 coronary stents (14 different types) by MDCT and the reasons for non-assessability were investigated. Furthermore, the evaluation of in-stent restenosis in 21 assessable stents of 16 patients, including quantitative density analysis by MDCT, was performed and the results were compared with those of conventional coronary angiography (CAG). RESULTS: Of 61 stents, 42 (68.9%) were assessable. The assessability of diameter > or =3.5-mm stents made of stainless steel or cobalt was high (88.6%, 31/35), that of 3.0-mm stents was low (57.9%, 11/19) and all 2.5-mm stents were non-assessable due to partial volume effects and metal artifacts of stents. The lumens of stents made of tantalum were totally obscured and the metal artifacts of Bestent2 (gold markers) and S670 were severer than others. All non-assessable stents due to banding artifact and calcification were implanted in segment #1-3 and #6, respectively. In comparison to CAG, MDCT correctly detected the 5 in-stent restenoses and identified absence of restenoses was influenced strongly by the stent strut. CONCLUSION: Despite some limitations, 16-slice MSCT is sufficiently useful for assessment of various coronary stents in patients and can detect in-stent restenoses of assessable stents with high accuracy in comparison to CAG.

Ability for visualization, reasons for nonassessable image, and diagnostic accuracy of 16-slice multidetector row helical computed tomography for the assessment of the entire coronary arteries.

It was demonstrated that 16-slice multidetector row helical computed tomography may permit more accurate assessment of entire coronary arteries, with a low rate of arteries unable to be evaluated. The detection of coronary artery stenoses with this modality was applicable to assessable segments.

Water solubility and partitioning behavior of brominated phenols.

The water solubility (Sw) in the temperature range from 283 to 308 K and 1-octanol/water partition coefficient (Kow) for the nonionic form of brominated phenols (BPhs) of varying bromine content (4-bromophenol, 2,4-dibromophenol, 2,4,6-tribromophenol, and pentabromophenol) were measured by the generator-column or shake-flask method and by the high-performance liquid chromatography method, respectively. The temperature dependence of Sw, namely enthalpy of solution (deltaHsolution), was calculated using the van't Hoff Equation. To determine the activity coefficients in water (gammaw) of BPhs from the Sw data, enthalpy of fusion (deltaHfusion) and melting point (Tm) were measured by a differential scanning calorimetry method. The gammaw was used for evaluating data consistency as well as for predicting other physico-chemical properties, such as the Henry's law constant (Hw). The present work systematically reports, to our knowledge for the first time, the experimental values of Sw, Kow, deltaHsolution, deltaHfusion, Tm, and gammaw for BPhs with one to five bromines, and it discusses the effects of bromine content on these physico-chemical properties. Finally, the overall physico-chemical characteristics of BPhs are compared with those of polychlorinated phenols, polycyclic aromatic hydrocarbons, and brominated benzenes with the same solubility level as BPhs.

Prediction of physico-chemical properties for PCs/DFs using the UNIFAC model with an alternative approximation for group assignment.

The original-type UNIFAC model was used to predict the environmentally important physico-chemical properties of PCDDs/DFs, such as aqueous solubility, Henry's law constant, and 1-octanol/water partition coefficient, through the UNIFAC-derived infinite dilution activity coefficient. In this application, we suggest an alternative approximation that the aromatic ether group AC-O in PCDD/DF molecules is replaced with the aliphatic ether group CH-O, because the AC-O group is not available in the conventional UNIFAC model. With this approximation, the ability of the UNIFAC model to predict those properties was examined by comparing with experimental data. The UNIFAC model provided comparatively good estimation results. From these results, it is shown that the alternative approximation is useful for the UNIFAC estimation of physico-chemical properties for PCDDs/DFs. Furthermore, the predicted solubilities of 2,3,7,8-T4CDD and O8CDD in organic solvents and the co-solvency effect on solubility of PCDDs in methanol/water mixture indicate that the UNIFAC calculation presented here could well predict the physico-chemical properties of PCDDs/DFs in various solution conditions.

Novel Phenomena of Crystallization and Emulsification of Hydrophobic Solute in Aqueous Solution.

Emulsification of lauric acid in an aqueous ethanol solution including lauric acid solute has been observed during cooling before crystallization of lauric acid occurs. The nature of two different solubility curves was explained for the system of lauric acid and aqueous ethanol solution. The mutual solubility of the two liquid phases controls emulsification; the solid solubility of lauric acid controls crystallization. The mutual solubility curve appears at relatively high temperature, and the solid solubility curve at relatively low temperature. Crystallization essentially generates a solid metastable zone under the solid solubility curve. A supersaturated solution can be obtained in the metastable zone. However, no nucleation occurs in the metastable zone. The metastable zone, therefore, still caused emulsification at low temperature before crystallization of lauric acid occurred. The hypothetical mutual solubility curve for the aqueous solution including hydrophobic solutes appeared invariably even at low temperature in the metastable zone under the solid solubility. Copyright 2001 Academic Press.