A novel use of CT attenuation value: increased bone marrow density in patients with acute myeloid leukemia.

BACKGROUND: Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults. Bone marrow computed tomography (CT) attenuation may increase in patients with myeloproliferative disorders; however, the actual threshold CT attenuation value predictive of myeloproliferative has not been reported. PURPOSE: To determine whether the unenhanced CT attenuation value of the bone marrow may be useful for predicting AML. MATERIAL AND METHODS: We retrospectively analyzed patients with AML (n = 56) who underwent unenhanced CT before treatment, and age- and sex-matched controls without any hematologic disease. For each patient, the CT attenuation value (HU) of the iliac bone was measured and compared between the two groups. Receiver operating characteristic (ROC) curve analysis was used to define the cutoff value for predicting AML on all patients, and only on late elderly patients (aged ≥75 years). RESULTS: Patients with AML showed higher bone marrow CT attenuation value (131.4 ± 58.3 vs. 53.9 ± 67.2 HU; P < 0.001), compared to the controls. The sensitivity and specificity for the diagnosis of AML in all patients were 78.6% and 80.4%, respectively, at a threshold value of 90 HU, whereas they were 83.3% and 91.7%, respectively, at 40 HU in late elderly patients. CONCLUSION: The iliac bone CT attenuation value was elevated in patients with AML and may be useful for predicting AML.

Yellowish lesions in the oesophagus.

CLINICAL PRESENTATION: A 51-year-old man, who had no previous disease, underwent a screening oesophagogastroduodenoscopy, which revealed multiple yellowish lesions in the middle thoracic oesophagus. All lesions were ≤3 mm in size and slightly elevated. Each lesion showed one or two white protrusions on the surface (figure 1). We observed that one lesion looked obviously different from the others and showed yellowish granular spots (figure 2). A biopsy was performed on a representative lesion among the slightly elevated yellowish lesions with white protrusions (figure 3). A biopsy was repeated on a lesion showing yellowish granular spots (figure 4). Blood tests which were examined on the same day, including triglyceride and cholesterol, were within normal limits. gutjnl;68/1/39/F1F1F1Figure 1Slightly elevated yellowish lesions with white protrusions in the middle thoracic oesophagus. gutjnl;68/1/39/F2F2F2Figure 2A lesion showing yellowish granular spots in the middle thoracic oesophagus. QUESTION: What is the diagnosis?

An array of porous microneedles for transdermal monitoring of intercellular swelling.

An array of porous microneedles was developed for minimally-invasive transdermal electrolytic connection through the human skin barrier, the stratum corneum. The length of microneedle was designed to be 100 µm so that it penetrates into the epidermis layer without pain. Each microneedle was supported by a thicker cylindrical post protruding from a planar substrate to realize its effective penetration even into elastic human skin. Since this support (post and substrate) was equally porous as the needles, the needle chip was entirely permeable for electrolyte. This ion-conductive porous microneedle array was applied to the transdermal conductometry with small direct current for local monitoring of intercellular swelling, edema. The porous needle-based electrode system could be a platform for various transdermal electrical diagnosis and treatments.

An Oxygen-Insensitive Hydrogen Evolution Catalyst Coated by a Molybdenum-Based Layer for Overall Water Splitting.

For overall water-splitting systems, it is essential to establish O2 -insensitive cathodes that allow cogeneration of H2 and O2 . An acid-tolerant electrocatalyst is described, which employs a Mo-coating on a metal surface to achieve selective H2 evolution in the presence of O2 . In operando X-ray absorption spectroscopy identified reduced Pt covered with an amorphous molybdenum oxyhydroxide hydrate with a local structural order composed of polyanionic trimeric units of molybdenum(IV). The Mo layer likely hinders O2 gas permeation, impeding contact with active Pt. Photocatalytic overall water splitting proceeded using MoOx /Pt/SrTiO3 with inhibited water formation from H2 and O2 , which is the prevailing back reaction on the bare Pt/SrTiO3 photocatalyst. The Mo coating was stable in acidic media for multiple hours of overall water splitting by membraneless electrolysis and photocatalysis.

Whisker experience-dependent mGluR signaling maintains synaptic strength in the mouse adolescent cortex.

Sensory experience-dependent plasticity in the somatosensory cortex is a fundamental mechanism of adaptation to the changing environment not only early in the development but also in adolescence and adulthood. Although the mechanisms underlying experience-dependent plasticity during early development have been well documented, the corresponding understanding in the mature cortex is less complete. Here, we investigated the mechanism underlying whisker deprivation-induced synaptic plasticity in the barrel cortex in adolescent mice. Layer 4 (L4) to L2/3 excitatory synapses play a crucial role for whisker experience-dependent plasticity in rodent barrel cortex and whisker deprivation is known to depress synaptic strength at L4-L2/3 synapses in adolescent and adult animals. We found that whisker deprivation for 5 days or longer decreased the presynaptic glutamate release probability at L4-L2/3 synapses in the barrel cortex in adolescent mice. This whisker deprivation-induced depression was restored by daily administration of a positive allosteric modulator of the type 5 metabotropic glutamate receptor (mGluR5). On the other hand, the administration of mGluR5 antagonists reproduced the effect of whisker deprivation in whisker-intact mice. Furthermore, chronic and selective suppression of inositol 1,4,5-trisphosphate (IP3 ) signaling in postsynaptic L2/3 neurons decreased the presynaptic release probability at L4-L2/3 synapses. These findings represent a previously unidentified mechanism of cortical plasticity, namely that whisker experience-dependent mGluR5-IP3 signaling in the postsynaptic neurons maintains presynaptic function in the adolescent barrel cortex.

Calcium-dependent N-cadherin up-regulation mediates reactive astrogliosis and neuroprotection after brain injury.

Brain injury induces phenotypic changes in astrocytes, known as reactive astrogliosis, which may influence neuronal survival. Here we show that brain injury induces inositol 1,4,5-trisphosphate (IP3)-dependent Ca(2+) signaling in astrocytes, and that the Ca(2+) signaling is required for astrogliosis. We found that type 2 IP3 receptor knockout (IP3R2KO) mice deficient in astrocytic Ca(2+) signaling have impaired reactive astrogliosis and increased injury-associated neuronal death. We identified N-cadherin and pumilio 2 (Pum2) as downstream signaling molecules, and found that brain injury induces up-regulation of N-cadherin around the injured site. This effect is mediated by Ca(2+)-dependent down-regulation of Pum2, which in turn attenuates Pum2-dependent translational repression of N-cadherin. Furthermore, we show that astrocyte-specific knockout of N-cadherin results in impairment of astrogliosis and neuroprotection. Thus, astrocytic Ca(2+) signaling and the downstream function of N-cadherin play indispensable roles in the cellular responses to brain injury. These findings define a previously unreported signaling axis required for reactive astrogliosis and neuroprotection following brain injury.

Photoelectrochemical oxidation of water using BaTaO2N photoanodes prepared by particle transfer method.

A photoanode of particulate BaTaO2N fabricated by the particle transfer method and modified with a Co cocatalyst generated a photocurrent of 4.2 mA cm(-2) at 1.2 V(RHE) in the photoelectrochemical water oxidation reaction under simulated sunlight (AM1.5G). The half-cell solar-to-hydrogen conversion efficiency (HC-STH) of the photoanode reached 0.7% at 1.0 V(RHE), which was an order of magnitude higher than the previously reported photoanode made from the same material. The faradaic efficiency for oxygen evolution from water was virtually 100% during the reaction for 6 h, attesting to the robustness of the oxynitride.

Recent advances in semiconductors for photocatalytic and photoelectrochemical water splitting.

Photocatalytic and photoelectrochemical water splitting under irradiation by sunlight has received much attention for production of renewable hydrogen from water on a large scale. Many challenges still remain in improving energy conversion efficiency, such as utilizing longer-wavelength photons for hydrogen production, enhancing the reaction efficiency at any given wavelength, and increasing the lifetime of the semiconductor materials. This introductory review covers the fundamental aspects of photocatalytic and photoelectrochemical water splitting. Controlling the semiconducting properties of photocatalysts and photoelectrode materials is the primary concern in developing materials for solar water splitting, because they determine how much photoexcitation occurs in a semiconductor under solar illumination and how many photoexcited carriers reach the surface where water splitting takes place. Given a specific semiconductor material, surface modifications are important not only to activate the semiconductor for water splitting but also to facilitate charge separation and to upgrade the stability of the material under photoexcitation. In addition, reducing resistance loss and forming p-n junction have a significant impact on the efficiency of photoelectrochemical water splitting. Correct evaluation of the photocatalytic and photoelectrochemical activity for water splitting is becoming more important in enabling an accurate comparison of a number of studies based on different systems. In the latter part, recent advances in the water splitting reaction under visible light will be presented with a focus on non-oxide semiconductor materials to give an overview of the various problems and solutions.

Enhancing photocatalytic activity of LaTiO2N by removal of surface reconstruction layer.

LaTiO2N is an oxynitride photocatalyst that has ability to generate H2 and O2 from water under irradiation of light with wavelengths up to 600 nm. However, LaTiO2N necessitates sacrificial reagents that capture either photoexcited electrons or holes efficiently to be active in the photocatalytic reactions because of a considerable number of defects that cause trapping and recombination of photoexcited carriers. Therefore, identifying defect structures of LaTiO2N is important. In this study, using atomic-resolution scanning transmission electron microscopy, we evidence that eliminating defective surface reconstructed layers of LaTiO2N particles by the treatment with aqua regia can double the photocatalytic activity.

Wafer-scale fabrication of self-catalyzed 1.7 eV GaAsP core-shell nanowire photocathode on silicon substrates.

We present the wafer-scale fabrication of self-catalyzed p-n homojunction 1.7 eV GaAsP core-shell nanowire photocathodes grown on silicon substrates by molecular beam epitaxy with the incorporation of Pt nanoparticles as hydrogen evolution cocatalysts. Under AM 1.5G illumination, the GaAsP nanowire photocathode yielded a photocurrent density of 4.5 mA/cm(2) at 0 V versus a reversible hydrogen electrode and a solar-to-hydrogen conversion efficiency of 0.5%, which are much higher than the values previously reported for wafer-scale III-V nanowire photocathodes. In addition, GaAsP has been found to be more resistant to photocorrosion than InGaP. These results open up a new approach to develop efficient tandem photoelectrochemical devices via fabricating GaAsP nanowires on a silicon platform.

A Photoelectrochemical Solar Cell Consisting of a Cadmium Sulfide Photoanode and a Ruthenium-2,2'-Bipyridine Redox Shuttle in a Non-aqueous Electrolyte.

A photoelectrochemical (PEC) cell consisting of an n-type CdS single-crystal electrode and a Pt counter electrode with the ruthenium-2,2'-bipyridine complex [Ru(bpy)3](2+/3+) as the redox shuttle in a non-aqueous electrolyte was studied to obtain a higher open-circuit voltage (V(OC)) than the onset voltage for water splitting. A V(OC) of 1.48 V and a short-circuit current (I(SC)) of 3.88 mA cm(-2) were obtained under irradiation by a 300 W Xe lamp with 420-800 nm visible light. This relatively high voltage was presumably due to the difference between the Fermi level of photo-irradiated n-type CdS and the redox potential of the Ru complex at the Pt electrode. The smooth redox reaction of the Ru complex with one-electron transfer was thought to have contributed to the high V(OC) and I(SC). The obtained V(OC) was more than the onset voltage of water electrolysis for hydrogen and oxygen generation, suggesting prospects for application in water electrolysis.

Nanostructured WO3 /BiVO4 photoanodes for efficient photoelectrochemical water splitting.

Nanostructured photoanodes based on well-separated and vertically oriented WO3 nanorods capped with extremely thin BiVO4 absorber layers are fabricated by the combination of Glancing Angle Deposition and normal physical sputtering techniques. The optimized WO3 -NRs/BiVO4 photoanode modified with Co-Pi oxygen evolution co-catalyst shows remarkably stable photocurrents of 3.2 and 5.1 mA/cm(2) at 1.23 V versus a reversible hydrogen electrode in a stable Na2 SO4 electrolyte under simulated solar light at the standard 1 Sun and concentrated 2 Suns illumination, respectively. The photocurrent enhancement is attributed to the faster charge separation in the electronically thin BiVO4 layer and significantly reduced charge recombination. The enhanced light trapping in the nanostructured WO3 -NRs/BiVO4 photoanode effectively increases the optical thickness of the BiVO4 layer and results in efficient absorption of the incident light.

Photoelectrochemical properties of SrNbO2N photoanodes for water oxidation fabricated by the particle transfer method.

SrNbO(2)N photoanodes, which have a band gap energy of 1.8 eV, were tested for photoelectrochemical water oxidation in water splitting. The photoanodes were fabricated either by a particle transfer method or an electrophoretic deposition method. The effects of the precursors, fabrication method, and CoOx catalyst loading were studied in order to identify the shortcomings of the photoanodes and improve their photoelectrochemical properties for water oxidation. SrNbO(2)N photoanodes fabricated by particle transfer generated a photocurrent that was one order of magnitude higher than that of photoanodes prepared via electrophoretic deposition. The stoichiometric oxide precursor (Sr(2)Nb(2)O(7)) was found to be preferable to the Sr-rich oxide precursor (Sr(5)Nb(4)O(15)). CoOx increased the photoanodic current on SrNbO(2)N photoelectrodes. Nevertheless, the incident photon-to-current efficiency was still limited to 10% at most. Potential problems with SrNbO(2)N photoanodes were discussed.

Fabrication of highly ordered Ta2O5 and Ta3N5 nanorod arrays by nanoimprinting and through-mask anodization.

Using highly ordered porous anodic alumina membrane fabricated with the aid of nanoimprinting as a mask, Ta2O5 nanorod array with uniform diameter, length, and distribution is grown in situ on a Ta substrate by through-mask anodization. The Ta2O5 nanorod array is further transformed into Ta3N5 nanorod array without damaging the nanorod structure by nitridation. Solar-driven photoelectrochemical water splitting with a maximum solar energy conversion efficiency of 0.36% is demonstrated with the Ta3N5 nanorod array after modifying the surface with cobalt-phosphate as a co-catalyst. The Ta2O5 and Ta3N5 nanorod arrays have potential applications in catalysis, photonics, UV photodetection and solar energy conversion.

Hydrogen evolution from water using Ag(x)Cu(1-x)GaSe2 photocathodes under visible light.

Photoelectrochemical (PEC) water splitting using CuGaSe2 (CGSe) thin film photocathodes modified by partial substitution of Cu with Ag was investigated. The AgxCu1-xGaSe2 (ACGSe) thin films were deposited onto Mo-coated soda-lime glass substrates by means of co-evaporation using a molecular beam epitaxy (MBE) system. The valence band maximum (VBM) potential of ACGSe is deeper than that of CGSe, and its grain size is greatly increased compared to that of CGSe. A Pt and CdS modified ACGSe electrode (Pt/CdS/ACGSe) with a Ag/(Cu + Ag) ratio of about 5% showed a cathodic photocurrent of 8.1 mA cm(-2) at 0 VRHE and an onset potential of 0.70 VRHE (defined as a cathodic photocurrent of 0.05 mA cm(-2)) under simulated sunlight in a 0.1 M Na2SO4 solution (pH 9.5). Moreover, Pt/CdS/ACGSe exhibited a stable cathodic photocurrent for over 55 h, with no clear decrease.