The microRNA-485-3p concentration in salivary exosome-enriched extracellular vesicles is related to amyloid β deposition in the brain of patients with Alzheimer's disease

OBJECTIVES

Alzheimer's disease (AD) is an irreversible neurodegenerative disease characterized by progressive long-term memory loss and cognitive dysfunction. Neuroimaging tests for abnormal amyloid-β (Aβ) deposition are considered the most reliable methods for the diagnosis of AD; however, the cost for such testing is very high and generally not covered by national insurance systems. Accordingly, it is only recommended for individuals exhibiting clinical symptoms of AD supported by clinical cognitive assessments. Recently, it was suggested that dysregulated microRNA-485-3p (miRNA-485-3p) in the brain and cerebrospinal fluid is closely related to pathogenesis of AD. However, a relationship between circulating miRNA-485-3p in salivary exosome-enriched extracellular vesicles (EE-EV) and Aβ deposition in the brain has not been observed.

DESIGN & METHODS

Using quantitative real-time polymerase chain reaction, we analyzed miRNA-485-3p concentration in salivary EE-EV. We used receiver operating characteristic (ROC) curve analysis to evaluate its predictive value for Aβ positron emission tomography (Aβ-PET) positivity in patients with AD.

RESULTS

Our results showed that the miRNA-485-3p concentration in salivary EE-EV isolated from patients with AD was significantly increased compared with that in the healthy controls (p<0.0001). In the analysis of all participants, the miRNA-485-3p concentration was significantly increased in Aβ-PET-positive participants compared to Aβ-PET-negative participants (p<0.0001). Further analysis using only AD patients also showed that the miRNA-485-3p concentration was significantly increased in Aβ-PET-positive AD patients vs. Aβ-PET-negative AD patients (p=0.0063). The ROC curve analysis for differentiating Aβ-PET-positive and negative participants showed that the area under the curve for miRNA-485-3p was 0.9217.

CONCLUSION

These findings suggested that the miRNA-485-3p concentration in salivary EE-EV was closely related to Aβ deposition in the brain and had high diagnostic accuracy for predicting Aβ-PET positivity.

Extreme UV Resist Exhibiting Synergism between Chemical and Physical Crosslinking Mechanisms

Carbon-fluorine bonds in fluorinated molecules can undergo homolytic cleavage reactions when electrons are injected, and the resulting radicals combine to form network structures characterized by reduced solubility. This crosslinking chemistry suggests a new category of patterning materials that function under electron beam (e-beam) and extreme ultraviolet (EUV) lithographic conditions. Although this chemistry enables the production of 50 nm or smaller-sized features of simple fluoroalkylated polymers, it is limited by the need for relatively large amounts of irradiation energy to achieve required solubility changes. Therefore, this study was undertaken to devise a sensitivity-enhancing strategy based on a synergistic combination of radical crosslinking and hydrogen-bonding interactions between highly fluoroalkylated copolymers. An alternating copolymer was synthesized using tert-butoxystyrene and a fluoroalkylated maleimide, the former of which produces active hydrogens through catalytic acidolysis reactions. When the polymer was blended with a catalytic amount of a photoacid generator and subjected to lithographic patterning tests under e-beam and EUV irradiation, the deprotection reactions of tert-butoxy moieties proceeded at room temperature and led to a solubility decrease. We presume the small number of hydroxyl moieties produced formed an intermolecular hydrogen-bonding network, which acted synergistically with the covalent crosslinks generated by C-F bonds. When 30 nm features of copolymer thin films were fabricated by EUV lithography, sensitivity was improved by 25-34% without significant deterioration of pattern quality, especially line-edge roughness. These results demonstrate that EUV resists with improved patterning capabilities can be achieved by combining catalytic acidolysis reactions and noncatalytic crosslinking chemistry.

Development of a humidity pretreatment method for the measurement of ozone in ambient air

A frost filter (FRF) was developed as a humidity pretreatment device (HPD) to improve the measurement of ambient ozone (O₃). The FRF was produced in a tube, which was supercooled by a thermoelectric cooling device based on the Peltier effect. The relative humidity (RH) of the air samples varied from 30% to 80% at 25 °C, and the O₃ concentration was set as 100 ppbv. Besides O₃, SO₂ at 150 ppbv was used for comparison. The density of the FRF was evaluated. Comparison studies on the humidity removal efficiencies and loss ratios of analytes among a FRF HPD, a short Nafion™ tube (NS), and a long Nafion™ tube (NL) HPDs were conducted. As results, the density of the FRF was dependent on the temperature at a fixed sampling flow rate. The outlet humidity of both the FRF and the NL HPDs were less than 8% RH at 25 °C. The mean concentrations of O₃ and SO₂ after the FRF HPD were similar to the initial concentrations at all humidity levels, whereas they were significantly different for both the NS and NL HPDs at higher humidity. This suggests that the FRF HPD is a reliable humidity pretreatment for O₃ measurements.

Direct Observation of Orbital Driven Strong Interlayer Coupling in Puckered Two-Dimensional PdSe2

Interlayer coupling between individual unit layers is known to be critical in manipulating the layer-dependent properties of two-dimensional (2D) materials. While recent studies have revealed that several 2D materials with significant degrees of interlayer interaction (such as black phosphorus) show strongly layer-dependent properties, the origin based on the electronic structure is drawing intensive attention along with 2D materials exploration. Here, the direct observation of a highly dispersive single electronic band along the interlayer direction in puckered 2D PdSe₂ as an experimental hallmark of strong interlayer couplings is reported. Remarkably large band dispersion along the k_z -direction near Fermi level, which is even wider than the in-plane one, is observed by the angle-resolved photoemission spectroscopy measurement. Employing X-ray absorption spectroscopy and density functional theory calculations, it is revealed that the strong interlayer coupling in 2D PdSe₂ originates from the unique directional bonding of Pd d orbitals associated with unexpected Pd 4d⁹ configuration, which consequently plays a decisive role for the strong layer-dependency of the band gap.

Investigation of correlative parameters to evaluate EUV lithographic performance of PMMA

Investigations to evaluate the extreme ultraviolet (EUV) lithographic performance of 160 nm thick poly(methyl methacrylate) with 13.5 nm wavelength EUV light were performed using a synchrotron radiation source at Pohang Light Source-II (PLS-II). The single system enabled the determination of the sensitivity, contrast, linear absorption coefficient, critical dimension, and line edge roughness of polymer thin films through tests and measurements. The experimental findings were also compared to theoretical results and those of previously reported studies. According to the results of the dose-to-clear test and transmission measurements, the critical dimension of a line and space pattern (>50 nm) via interference lithography with 250 nm pitch grating agreed well with the results calculated using the lumped parameter model. The experimental results demonstrated that the equipment and test protocol can be used for EUV material infrastructure evaluation in academia and in industry.

Studying local Berry curvature in 2H-WSe2 by circular dichroism photoemission utilizing crystal mirror plane

It was recently reported that circular dichroism in angle-resolved photoemission spectroscopy (CD-ARPES) can be used to observe the Berry curvature in 2H-WSe₂ (Cho et al. in Phys Rev Lett 121:186401, 2018). In that study, the mirror plane of the experiment was intentionally set to be perpendicular to the crystal mirror plane, such that the Berry curvature becomes a symmetric function about the experimental mirror plane. In the present study, we performed CD-ARPES on 2H-WSe₂ with the crystal mirror plane taken as the experimental mirror plane. Within such an experimental constraint, two experimental geometries are possible for CD-ARPES. The Berry curvature distributions for the two geometries are expected to be antisymmetric about the experimental mirror plane and exactly opposite to each other. Our experimental CD intensities taken with the two geometries were found to be almost opposite near the corners of the 2D projected hexagonal Brillouin zone (BZ) and were almost identical near the center of the BZ. This observation is well explained by taking the Berry curvature or the atomic orbital angular momentum (OAM) into account. The Berry curvature (or OAM) contribution to the CD intensities can be successfully extracted through a comparison of the CD-ARPES data for the two experimental geometries. Thus, the CD-ARPES experimental procedure described provides a method for mapping Berry curvature in the momentum space of topological materials, such as Weyl semimetals.

Perfluoroalkylated alternating copolymer possessing solubility in fluorous liquids and imaging capabilities under high energy radiation

A highly fluorinated alternating polymer, P(RFMi-St), possessing improved thermal properties and patterning capabilities over perfluoroalkyl polymethacrylates under high energy radiation was achieved with semi-perfluorododecyl maleimide (RFMi) and styrene (St). RFMi could be synthesised efficiently via a Mitsunobu reaction condition and copolymerised with St by free radical and reversible-deactivation radical polymerisation protocols. P(RFMi-St) showed a satisfactory glass-transition temperature (108 °C) and intermolecular cross-linking behaviour under electron-beam and commercially more important extreme UV (λ = 13.5 nm) irradiation. The exposed regions lost their solubility, resulting in the successful formation of mechanically non-deteriorated negative-tone images down to 50 nm. In addition, P(RFMi-St) could be solution-processed with chemically non-damaging fluorous liquids, which enabled the polymer to be applied effectively on top of an organic semiconductor layer as a dielectric material (dielectric constant 2.7) for the organic field-effect transistor fabrication.

Diagnostic and therapeutic biomarkers for Alzheimer's disease in human-derived platelets

BACKGROUND

Diagnosis of current Alzheimer's disease (AD) is difficult even for medical specialists, and there is no clear biomarker. Also, aging is highly related to the onset of AD.

OBJECTIVES

The purpose of this study is to screen miRNA as an aging-considered biomarker for AD treatment and diagnosis.

METHODS

The patient group for this study was divided into a young normal, old normal, or AD group. We developed a method of discovering sequentially expressed miRNAs to distinguish miRNAs that were sequentially expressed in the three groups.

RESULTS

Sequentially expressed miRNAs correlated highly with the patient's age, and most showed expression patterns that distinguished young, old, and AD. Specifically, the miRNA expression we found showed similar patterns in the brains of patients with AD. Among the selected miRNAs, one set derived from the same precursor: The expression of miR-150 was a disease- and age-specific downregulation in both 3p and 5p forms, and the precursor also had the same pattern. We named that triple matching. Also, the found miR-150 precursor had AD-specific miRNA-imbalance characteristics.

CONCLUSIONS

We developed a novel AD diagnostic method using triple matching and miRNA-imbalance. The triple matching and miRNA imbalance-based relative ratio diagnosis method we developed will be very powerful in resolving the challenges of absolute diagnostic quantification based on biomarker expression. Also, our research results suggest the possibility of a treatment target for AD.

Emergence of Kondo Resonance in Graphene Intercalated with Cerium

The interaction between a magnetic impurity, such as cerium (Ce) atom, and surrounding electrons has been one of the core problems in understanding many-body interaction in solid and its relation to magnetism. Kondo effect, the formation of a new resonant ground state with quenched magnetic moment, provides a general framework to describe many-body interaction in the presence of magnetic impurity. In this Letter, a combined study of angle-resolved photoemission (ARPES) and dynamic mean-field theory (DMFT) on Ce-intercalated graphene shows that Ce-induced localized states near Fermi energy, E_F, hybridized with the graphene π-band, exhibit gradual increase in spectral weight upon decreasing temperature. The observed temperature dependence follows the expectations from the Kondo picture in the weak coupling limit. Our results provide a novel insight how Kondo physics emerges in the sea of two-dimensional Dirac electrons.

Charge-Spin Correlation in van der Waals Antiferromagnet NiPS_{3}

Strong charge-spin coupling is found in a layered transition-metal trichalcogenide NiPS_{3}, a van der Waals antiferromagnet, from studies of the electronic structure using several experimental and theoretical tools: spectroscopic ellipsometry, x-ray absorption, photoemission spectroscopy, and density functional calculations. NiPS_{3} displays an anomalous shift in the optical spectral weight at the magnetic ordering temperature, reflecting strong coupling between the electronic and magnetic structures. X-ray absorption, photoemission, and optical spectra support a self-doped ground state in NiPS_{3}. Our work demonstrates that layered transition-metal trichalcogenide magnets are useful candidates for the study of correlated-electron physics in two-dimensional magnetic materials.

Atomically Abrupt Topological p-n Junction

Topological insulators (TI's) are a new class of quantum matter with extraordinary surface electronic states, which bear great potential for spintronics and error-tolerant quantum computing. In order to put a TI into any practical use, these materials need to be fabricated into devices whose basic units are often p-n junctions. Interesting electronic properties of a 'topological' p-n junction were proposed theoretically such as the junction electronic state and the spin rectification. However, the fabrication of a lateral topological p-n junction has been challenging because of materials, process, and fundamental reasons. Here, we demonstrate an innovative approach to realize a p-n junction of topological surface states (TSS's) of a three-dimensional (3D) topological insulator (TI) with an atomically abrupt interface. When a ultrathin Sb film is grown on a 3D TI of Bi₂Se₃ with a typical n-type TSS, the surface develops a strongly p-type TSS through the substantial hybridization between the 2D Sb film and the Bi₂Se₃ surface. Thus, the Bi₂Se₃ surface covered partially with Sb films bifurcates into areas of n- and p-type TSS's as separated by atomic step edges with a lateral electronic junction of as short as 2 nm. This approach opens a different avenue toward various electronic and spintronic devices based on well-defined topological p-n junctions with the scalability down to atomic dimensions.

A novel allele, HLA-C*14:02:01:03, identified by full-length genomic sequencing

The HLA-C*14:02:01:03 differs by a single nucleotide at intron 5 (2157 C>T) compared with C*14:02:01:01.

Experimental Realization of Type-II Dirac Fermions in a PdTe_{2} Superconductor

A Dirac fermion in a topological Dirac semimetal is a quadruple-degenerate quasiparticle state with a relativistic linear dispersion. Breaking either time-reversal or inversion symmetry turns this system into a Weyl semimetal that hosts double-degenerate Weyl fermion states with opposite chiralities. These two kinds of quasiparticles, although described by a relativistic Dirac equation, do not necessarily obey Lorentz invariance, allowing the existence of so-called type-II fermions. The recent theoretical discovery of type-II Weyl fermions evokes the prediction of type-II Dirac fermions in PtSe_{2}-type transition metal dichalcogenides, expecting experimental confirmation. Here, we report an experimental realization of type-II Dirac fermions in PdTe_{2} by angle-resolved photoemission spectroscopy combined with ab initio band calculations. Our experimental finding shows the first example that has both superconductivity and type-II Dirac fermions, which turns the topological material research into a new phase.

Identification of a novel allele, HLA-A*26:01:01:03N, by full-length genome sequencing

The HLA-A*26:01:01:03N allele shows a single nucleotide difference compared with HLA-A*26:01:01:01 in intron 4(1846 G>A).

2D MATERIALS. Observation of tunable band gap and anisotropic Dirac semimetal state in black phosphorus

Black phosphorus consists of stacked layers of phosphorene, a two-dimensional semiconductor with promising device characteristics. We report the realization of a widely tunable band gap in few-layer black phosphorus doped with potassium using an in situ surface doping technique. Through band structure measurements and calculations, we demonstrate that a vertical electric field from dopants modulates the band gap, owing to the giant Stark effect, and tunes the material from a moderate-gap semiconductor to a band-inverted semimetal. At the critical field of this band inversion, the material becomes a Dirac semimetal with anisotropic dispersion, linear in armchair and quadratic in zigzag directions. The tunable band structure of black phosphorus may allow great flexibility in design and optimization of electronic and optoelectronic devices.

A new HLA-B*15 allele, HLA-B*15:263, identified in a Korean individual

HLA-B*15:263 differs from HLA-B*15:18:01 by a single nucleotide exchange at position 824, C>G (codon 251 TCT>TGT).

Magnetic origin of giant magnetoelectricity in doped Y-type hexaferrite Ba(0.5)Sr(1.5)Zn(2)(Fe(1-x)Al(x))(12)O(22)

We investigated site-specific magnetic behaviors of multiferroic Ba(0.5)Sr(1.5)Zn(2)(Fe(1-x)Al(x))(12)O(22) using Fe L(2,3)-edge x-ray magnetic circular dichroism. The Al dopants mostly replace the Fe(3+) ions at octahedral (O(h)) sites, which contribute unquenched angular momenta through off-centering displacements. This replacement greatly reduces the magnetic anisotropy energy to change the magnetic order from a helical to a heliconical type with enhanced magnetoelectric susceptibility (α(ME)). The tetrahedral (T(d)) Fe sites exhibit magnetic hysteresis distinguishable from that of the O(h) sites, especially at low magnetic fields. These results provide essential clues for the heliconical order with a giant α(ME) and multibit memory effects in the Al-doped Y-type hexaferrite.

Identification of a new HLA-DRB1*04 allele, DRB1*04:10:03

The new allele, DRB1*04:10:03, showed one nucleotide difference with DRB1*04:10:01 (705C>T).

A new HLA-A*02 allele, A*02:465

The new allele A*02:465 showed one nucleotide difference with A*02:06:01 (172G>A).

Direct observation of localized spin antiferromagnetic transition in PdCrO2 by angle-resolved photoemission spectroscopy

We report the first case of the successful measurements of a localized spin antiferromagnetic transition in delafossite-type PdCrO2 by angle-resolved photoemission spectroscopy (ARPES). This demonstrates how to circumvent the shortcomings of ARPES for investigation of magnetism involved with localized spins in limited size of two-dimensional crystals or multi-layer thin films that neutron scattering can hardly study due to lack of bulk compared to surface. Also, our observations give direct evidence for the spin ordering pattern of Cr(3+) ions in PdCrO2 suggested by neutron diffraction and quantum oscillation measurements, and provide a strong constraint that has to be satisfied by a microscopic mechanism for the unconventional anomalous Hall effect recently reported in this system.

Feasibility study on development of Cerenkov fiber-optic dosimeter for radiotherapy application

To obtain real-time dose information in photon-beam therapy using a clinical linear accelerator, we fabricated a novel Cerenkov fiber-optic dosimeter using two plastic optical fibers without employing a scintillator. In this study, the light intensity and spectrum of Cerenkov radiation induced by a high-energy photon beam were measured as functions of the irradiation angle and the length difference between the two plastic optical fibers in the dosimeter probe. Also, we obtained a percentage depth dose curve for a 6 MV photon beam with a field size of 10 × 10 cm(2) according to the depth of the solid water phantom. Based on the results of this study, it is anticipated that the proposed Cerenkov fiber-optic dosimeter can be developed as a useful dosimeter to accurately obtain dose information prior to conducting radiotherapy.

Electrical measurement of antiferromagnetic moments in exchange-coupled IrMn/NiFe stacks

We employ antiferromagnetic tunneling anisotropic magnetoresistance to study the behavior of antiferromagnetically ordered moments in IrMn exchange coupled to NiFe. Experiments performed by common laboratory tools for magnetization and electrical transport measurements allow us to directly link the broadening of the NiFe hysteresis loop and its shift (exchange bias) to the rotation and pinning of antiferromagnetic moments in IrMn. At higher temperatures, the broadened loops show zero shift, which correlates with the observation of fully rotating antiferromagnetic moments inside the IrMn film. The onset of exchange bias at lower temperatures is linked to a partial rotation between distinct metastable states and pinning of the IrMn antiferromagnetic moments in these states. The observation complements common pictures of exchange bias and reveals an electrically measurable memory effect in an antiferromagnet.

A spin-valve-like magnetoresistance of an antiferromagnet-based tunnel junction

A spin valve is a microelectronic device in which high- and low-resistance states are realized by using both the charge and spin of carriers. Spin-valve structures used in modern hard-drive read heads and magnetic random access memoriescomprise two ferromagnetic electrodes whose relative magnetization orientations can be switched between parallel and antiparallel configurations, yielding the desired giant or tunnelling magnetoresistance effect. Here we demonstrate more than 100% spin-valve-like signal in a NiFe/IrMn/MgO/Pt stack with an antiferromagnet on one side and a non-magnetic metal on the other side of the tunnel barrier. Ferromagneticmoments in NiFe are reversed by external fields of approximately 50  mT or less, and the exchange-spring effect of NiFe on IrMn induces rotation of antiferromagnetic moments in IrMn, which is detected by the measured tunnelling anisotropic magnetoresistance. Our work demonstrates a spintronic element whose transport characteristics are governed by an antiferromagnet. It demonstrates that sensitivity to low magnetic fields can be combined with large, spin-orbit-coupling-induced magnetotransport anisotropy using a single magnetic electrode. The antiferromagnetic tunnelling anisotropic magnetoresistance provides a means to study magnetic characteristics of antiferromagnetic films by an electronic-transport measurement.

Tunneling anisotropic magnetoresistance in multilayer-(Co/Pt)/AlO_(x)/Pt structures

We report observations of tunneling anisotropic magnetoresitance (TAMR) in vertical tunnel devices with a ferromagnetic multilayer-(Co/Pt) electrode and a nonmagnetic Pt counterelectrode separated by an AlOx barrier. In stacks with the ferromagnetic electrode terminated by a Co film the TAMR magnitude saturates at 0.15% beyond which it shows only weak dependence on the magnetic field strength, bias voltage, and temperature. For ferromagnetic electrodes terminated by two monolayers of Pt we observe order(s) of magnitude enhancement of the TAMR and a strong dependence on field, temperature and bias. The discussion of experiments is based on relativistic ab initio calculations of magnetization orientation dependent densities of states of Co and Co/Pt model systems.

Tunnel spin polarization versus energy for clean and doped Al2O3 barriers

The variation of the tunnel spin-polarization (TSP) with energy is determined using a magnetic tunnel transistor, allowing quantification of the energy dependent TSP separately for both ferromagnet/insulator interfaces and direct correlation with the tunnel magnetoresistance (TMR) measured in the same device. The intrinsic TSP is reduced below the Fermi level, and more strongly so for tunneling into empty states above the Fermi level. For artificially doped barriers, the low bias TMR decreases due to defect-assisted tunneling. Yet, this mechanism becomes ineffective at large bias, where instead inelastic spin scattering causes a strong TMR decay.

Opposite spin asymmetry of elastic and inelastic scattering of nonequilibrium holes injected into a ferromagnet

The spin asymmetry of elastic and inelastic scattering of nonequilibrium holes injected into Co thin films is examined using a p-type magnetic tunnel transistor. Spin-dependent transmission yields a positive or negative magnetocurrent depending on Co thickness and hole energy. Up to a critical thickness of about 3 nm, (quasi)elastic scattering dominates with a short attenuation length (<1 nm) and preferential attenuation of holes in the majority spin bands, consistent with spin-wave emission. At a larger Co thickness, inelastic scattering dominates with a larger attenuation length ( approximately 4 nm) and opposite spin asymmetry.

High performance biofilm process for treating wastewater discharged from coal refining plants containing nitrogen, cyanide and thiocyanate

Wastewater discharge from coal refining plants contains a number of biologically toxic compounds; 2000-2500 mg/l of COD of which 40% is composed of phenol, 100-400 mg/l of thiocyanate, 10-40 mg/l of cyanide, 100-250 mg/l of NH4+-N and 150-300 mg/l of total nitrogen. In order to treat this kind of high strength wastewater, we have developed a high performance biofilm process using fluidizing bio-carriers of the tube chip type. The fluidizing biofilm carriers are made of a composite of polyethylene and several inorganic materials, whose density is controlled at 0.97-0.98 g/ml. The fluidizing biofilm carriers show sound fluidization characteristics inside bioreactors. The wastewater is treated using three consecutive series reactors in oxic-anoxic-oxic arrangement. Each reactor is charged with the fluidizing biofilm carriers of 50 vol%. Furthermore, newly cultured active microorganisms for the thiocyanate biodegradation are added in the biofilm process. At total hydraulic retention time of 2.2 days, this process can achieve steady state removal efficiencies: COD, 99%; thiocyanate, 99%; NH4+-N, 99% and total nitrogen, 90%.

Hypertrophic non-union of the first rib causing thoracic outlet syndrome: a case report

We experienced a rare case of thoracic outlet syndrome caused by hypertrophic nonunion of the first rib. A diagnosis was made mainly upon provocative tests and imaging studies. Pain and tingling could be reproduced and the radial pulse obliterated by the hyperabduction test. Abundant callus formation on the posterior aspect of the first rib with fracture line was visible on plain radiograph. Two-dimensional computed tomography showed right thoracic outlet narrowing mainly caused by the mass-effect of the callus. Dynamic arteriographic studies revealed an external compression of the right subclavian artery and duplex ultrasonography demonstrated a reduction in right subclavian artery blood flow when the shoulder is in 90 degrees of abduction. Surgery was performed after the conservative management for three months which failed to relieve the patient of his complaints. Resection of the first rib via transaxillary approach was undergone uneventfully in combination with the myotomy of the scalenus anticus muscle. At postoperative one year follow up, the patient was free of symptoms, and had a full range of motion of the right shoulder with no evidence of arterial insufficiency.

Continuous ethanol production from concentrated wood hydrolysates in an internal membrane-filtration bioreactor

Continuous culture for the production of ethanol from wood hydrolysate was carried out in an internal membrane-filtration bioreactor. The hydrolysate medium was sterilized at a relatively low temperature of 60 degrees C with the intention of reducing the formation of inhibitory compounds during the sterilization. The maximum ethanol concentration and productivity obtained in this study were 76.9 g/L and 16.9 g/L-h, respectively, which were much higher than those (57.2-67 g/L and 0.3-1.0 g/L-h) obtained in batch cultures using hydrolysate media sterilized at 60 degrees C. The productivity was also found to be much higher than that (6.7 g/L-h) obtained in a continuous cell retention culture using a wood hydrolysate sterilized at 121 degrees C. These results show that the internal membrane-filtration bioreactor in combination with low-temperature sterilization could be very effective for ethanol production from wood hydrolysate.

Clinical significance of intrahepatic biliary stricture in efficacy of hepatic resection for intrahepatic stones

In the Far East, hepatic resection is the definitive treatment for complicated intrahepatic stones (IHS). However, many investigators have reported that the associated intrahepatic biliary stricture is the main cause of treatment failure. A retrospective comparative study was undertaken to clarify the long-term efficacy of hepatic resection for treatment of IHS and to investigate the clinical significance of intrahepatic biliary stricture in treatment failure after hepatic resection performed in 44 patients with symptomatic IHS. The patients were divided into two study groups: group A, with intrahepatic biliary stricture (n = 28) and group B, without stricture (n = 16). Residual or recurrent stones, recurrence of intrahepatic biliary stricture, late cholangitis, and final outcomes were analyzed and compared statistically between the two groups. The patients were followed up for a median duration of 65 months after hepatectomy. The overall incidence of residual or recurrent stones was 36% and 11%, respectively, in groups A and B. The initial treatment failure rate was 50% in group A and 31% in group B. Intrahepatic biliary stricture recurred in 46% of patients in group A, while none of the group B patients had biliary stricture recurrence (P = 0.001). More than two-thirds of the restrictures in group A were identified at the primary site. The incidence of late cholangitis was higher in group A (54%) than in group B (6%) (P = 0. 002). Three-quarters of the patients with cholangitis in group A had severe cholangitis, that was recurrent, and related to stones and strictures (n = 11). They and 2 asymptomatic patients in group B required secondary procedures done at a median of 12 months after hepatectomy. Final outcomes after hepatectomy with or without secondary management were good in 80%, fair in 16%, and poor in 4% of our 44 patients. Most recurrent cholangitis after hepatectomy in patients with IHS was related to recurrent intrahepatic ductal strictures. Therefore, to be effective, hepatic resection should include the strictured duct. However, with hepatectomy alone it is difficult to clear the IHS or relieve the ductal strictures completely, particularly in patients with bilateral IHS, so perioperative team approaches that include both radiologic and cholangioscopic interventions should be combined for the effective management of IHS.

Characteristics of Ca2+ release mechanisms from an intracellular Ca2+ store in rabbit coronary artery

To elucidate the Ca2+ release mechanisms in the rabbit coronary artery, arterial preparations were permeabilized with beta-escin and changes in tension were measured under varying experimental conditions. Additionally, we investigated properties and distribution of two kinds of Ca2+ release mechanisms, Ca2+-induced Ca2+ release (CICR) and IP3-induced Ca2+ release (IICR). The results obtained were summarized as follows; 1. When a rabbit coronary artery was incubated in a relaxing solution containing 30 microM beta-escin for 40 min. sensitivity to externally added Ca2+ was much higher in beta-escin permeabilized muscle than in intact preparations. The contractile effect of IP3 in beta-escin permeabilized muscle was also demonstrated; 2. Caffeine and IP3 contracted coronary arteries were permeabilized with beta-escin, but the amplitude of contraction was much larger in the presence of caffeine than of IP3. 3. Intracellular heparin completely inhibited the contractions induced by IP3, but not those by caffeine. On the other hand, procaine inhibited the responses to caffeine, but not those to IP3. Ryanodine inhibited both the caffeine- and IP3-induced contractions. 4. The amplitude of contractile responses was much larger to the maximal stimulation of CICR by applying caffeine than to the maximal stimulation of IICR by applying IP3. After the maximal CICR stimulation by caffeine, the activation of IICR by IP3 without the reloading of Ca2+ could no longer evoke contraction. On the other hand, after the maximal IICR activation, the activation of CICR could still evoke contraction although the amplitude of the contraction was smaller when compared with the case without the initial IICR stimulation. 5. Acetylcholine contracted coronary artery smooth muscles were permeabilized with beta-escin. However, in the absence of added guanosine triphosphate (GTP), the responses were very small. Acetylcholine-induced contraction was inhibited by heparin, but not by procaine. From the above results, it may be concluded that there are two kinds of mechanisms of Ca2+ release, CICR and IICR, in the rabbit coronary artery smooth muscle cell. Also, whereas the CICR mechanism distributes on the membrane of the whole smooth muscle Ca2+ store, the IICR mechanism distributes only on a part of it.