Deep-learning reconstruction with low-contrast media and low-kilovoltage peak for CT of the liver.

AIM: To compare images using reduced CM, low-kVp scanning and DLR reconstruction with conventional images (no CM reduction, normal tube voltage, reconstructed with HBIR. To compare images using reduced contrast media (CM), low kilovoltage peak (kVp) scanning and deep-learning reconstruction (DLR) with conventional image quality (no CM reduction, normal tube voltage, reconstructed with hybrid-type iterative reconstruction method [HBIR protocol]). MATERIALS AND METHODS: A retrospective analysis was performed on 70 patients with liver disease and three-phase dynamic imaging using computed tomography (CT) from April 2020 to March 2022 at Oita University Hospital. Of these cases, 39 were reconstructed using the DLR protocol at a tube voltage of 80 kVp and CM of 300 mg iodine/kg while 31 were imaged at a tube voltage of 120 kVp with CM of 600 mg iodine/kg and were reconstructed by the usual HBIR protocol. Images from the DLR and HBIR protocols were analysed and compared based on the contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR), figure-of-merit (FOM), and visual assessment. The CT dose index (CTDI)vol and size-specific dose estimates (SSDE) were compared with respect to radiation dose. RESULTS: The DLR protocol was superior, with significant differences in CNR, SNR, and FOM except hepatic parenchyma in the arterial phase. For visual assessment, the DLR protocol had better values for vascular visualisation for the portal vein, image noise, and contrast enhancement of the hepatic parenchyma. Regarding comparison of the radiation dose, the DLR protocol was superior for all values of CTDIvol and SSDE, with significant differences (p<0.01; max. 52%). CONCLUSION: Protocols using DLR with reduced CM and low kVp have better image quality and lower radiation dose compared to protocols using conventional HBIR.

Phenomenological Constraints on the Transport Properties of QCD Matter with Data-Driven Model Averaging.

Using combined data from the Relativistic Heavy Ion and Large Hadron Colliders, we constrain the shear and bulk viscosities of quark-gluon plasma (QGP) at temperatures of ∼150-350 MeV. We use Bayesian inference to translate experimental and theoretical uncertainties into probabilistic constraints for the viscosities. With Bayesian model averaging we propagate an estimate of the model uncertainty generated by the transition from hydrodynamics to hadron transport in the plasma's final evolution stage, providing the most reliable phenomenological constraints to date on the QGP viscosities.

Improving the Quality of Synthetic FLAIR Images with Deep Learning Using a Conditional Generative Adversarial Network for Pixel-by-Pixel Image Translation.

BACKGROUND AND PURPOSE: Synthetic FLAIR images are of lower quality than conventional FLAIR images. Here, we aimed to improve the synthetic FLAIR image quality using deep learning with pixel-by-pixel translation through conditional generative adversarial network training. MATERIALS AND METHODS: Forty patients with MS were prospectively included and scanned (3T) to acquire synthetic MR imaging and conventional FLAIR images. Synthetic FLAIR images were created with the SyMRI software. Acquired data were divided into 30 training and 10 test datasets. A conditional generative adversarial network was trained to generate improved FLAIR images from raw synthetic MR imaging data using conventional FLAIR images as targets. The peak signal-to-noise ratio, normalized root mean square error, and the Dice index of MS lesion maps were calculated for synthetic and deep learning FLAIR images against conventional FLAIR images, respectively. Lesion conspicuity and the existence of artifacts were visually assessed. RESULTS: The peak signal-to-noise ratio and normalized root mean square error were significantly higher and lower, respectively, in generated-versus-synthetic FLAIR images in aggregate intracranial tissues and all tissue segments (all P < .001). The Dice index of lesion maps and visual lesion conspicuity were comparable between generated and synthetic FLAIR images (P = 1 and .59, respectively). Generated FLAIR images showed fewer granular artifacts (P = .003) and swelling artifacts (in all cases) than synthetic FLAIR images. CONCLUSIONS: Using deep learning, we improved the synthetic FLAIR image quality by generating FLAIR images that have contrast closer to that of conventional FLAIR images and fewer granular and swelling artifacts, while preserving the lesion contrast.

Revisiting the supratrigeminal nucleus in the rat.

The supratrigeminal nucleus (Vsup), originally proposed as a premotoneuron pool in the trigeminal reflex arc, is a key structure of jaw movement control. Surprisingly, however, the location of the rat Vsup has not precisely been defined. In light of our previous cat studies, we made two hypotheses regarding the rat Vsup: (1) the Vsup is cytoarchitectonically distinguishable from its surrounding structures; (2) the Vsup receives central axon terminals of the trigeminal mesencephalic nucleus (Vmes) neurons which are primary afferents innervating muscle spindles of jaw-closing muscles and periodontal ligaments around the teeth. To test the first hypothesis, we examined the cytoarchitecture of the rat Vsup. The Vsup was identified as an area medially adjacent to the dorsomedial part of trigeminal principal sensory nucleus (Vp), and extended from the level just rostral to the caudal two-thirds of the trigeminal motor nucleus (Vmo) to the level approximately 150 µm caudal to the Vmo. Our rat Vsup was much smaller and its location was considerably different in comparison to the Vsup reported previously. To evaluate the second hypothesis, we tested the distribution patterns of Vmes primary afferent terminals in the cytoarchitectonically identified Vsup. After transganglionic tracer applications to the masseter, deep temporal, and medial pterygoid nerves, a large number of axon terminals were observed in all parts of Vsup (especially in its medial part). After applications to the inferior alveolar, infraorbital, and lingual nerves, a small number of axon terminals were labeled in the caudolateral Vsup. The Vsup could also be identified electrophysiologically. After electrical stimulation of the masseter nerve, evoked potentials with slow negative component were isolated only in the Vsup. The present findings suggest that the rat Vsup can be cytoarchitectonically and electrophysiologically identified, receives somatotopic termination of the trigeminal primary afferents, and principally receives strong termination of the spindle Vmes primary afferents.

Optical properties of a conjugated-polymer-sensitised solar cell: the effect of interfacial structure.

Dye-sensitised solar cells (DSSCs) have sparked considerable interest over two decades. Recently, a method of polymer-wire sensitisation was demonstrated; the polymer is suggested to form a hole transport pathway (wire) following initial charge separation. We predict the optical properties of this polymer in various interfacial configurations, including the effects of chain length and attachment to {100} or {101} TiO2 facets. Contrary to most DSSCs, the {100} facet model best describes the experimental spectrum, predicting a relative thickness of 5.7 ± 0.2 µm, although {101} attachment, if implemented, may improve collection efficiency. Long chains are optimal, and stable attachment sites show minimal differences to absorbance in the major solar emission (visible) band. Combinations of {100}, {101}, and pseudo-bulk TiO2 models in three-parameter fits to experiment confirm the relative importance of the {100} facet.

Tuning of the fluorescence wavelength of CdTe quantum dots with 2 nm resolution by size-selective photoetching.

Photoetching of CdTe nanocrystals was applied to thiol-capped CdTe quantum dots (QDs) to control their fluorescence wavelength. CdTe QDs with a high quantum yield (49%) were synthesized in aqueous solution, and they were successfully photoetched in strong alkaline (pH = 13.5) conditions. When monochromatic light was used, size-selective photoetching could be conducted; the photoetching proceeded until the band gap energy of the CdTe QDs increased to the energy corresponding to the wavelength of the irradiating light. As a result, a good linear relationship was obtained between the wavelength of the irradiating light and that of the fluorescence peak. The resulting CdTe QDs exhibited a fluorescence peak with an FWHM value as small as 23.5 nm, indicating preparation of highly monodispersed nanocrystals. The high quantum yield (ca. 45%) was maintained after the photoetching. Very fine tuning of the fluorescence wavelength with 2 nm resolution was achieved by changing the wavelength of the irradiating light by 2 nm. Theoretical calculation of the quantum size effects (effective mass approximation) predicts that a difference in the band gap fluorescence wavelength of 2 nm corresponds to a change in particle diameter of ca. 0.02 nm.

Variability of parvovirus B19 to inactivation by liquid heating in plasma products.

BACKGROUND AND OBJECTIVES: Previously, we reported that although human parvovirus B19 in albumin and intravenous immunoglobulin preparations was rapidly inactivated during liquid heating, in contrast to other parvoviruses such as canine parvovirus, sensitivity to heat was highly dependent on the composition of the solution. In this study, we aimed to further elucidate the sensitivity to heat of B19 in haptoglobin and antithrombin (previously named antithrombin III) preparations during liquid heating. MATERIALS AND METHODS: Two different solutions collected immediately before heat treatment of haptoglobin and antithrombin preparations were spiked with B19 and subsequently treated at 60 degrees C for 10 h. B19 DNA-positive, anti-B19 IgG/IgM-negative plasma was used as a source of B19. The residual infectivity in each sample was measured using a B19 cell-based infectivity assay with an mRNA polymerase chain reaction. RESULTS: B19 in different plasma preparations showed different heat-sensitivity patterns during liquid heating: (i) slow inactivation in haptoglobin preparations, and (ii) only limited inactivation in antithrombin preparations. The kinetics of inactivation was greatly different from that in our previous studies in which the virus was shown to be rapidly inactivated in albumin and intravenous immunoglobulin preparations. CONCLUSION: B19 has unique properties in terms of heat sensitivity, depending on the composition of the solution during liquid heating. This finding may indicate the need for caution when interpreting the sensitivity of B19 to heat.

Down-regulation of metabotropic glutamate receptor 1alpha in globus pallidus and substantia nigra of parkinsonian monkeys.

Enhanced glutamatergic neurotransmission via the subthalamopallidal or subthalamonigral projection seems crucial for developing parkinsonian motor signs. In the present study, the possible changes in the expression of metabotropic glutamate receptors (mGluRs) were examined in the basal ganglia of a primate model for Parkinson's disease. When the patterns of immunohistochemical localization of mGluRs in monkeys administered systemically with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were analysed in comparison with normal controls, we found that expression of mGluR1alpha, but not of other subtypes, was significantly reduced in the internal and external segments of the globus pallidus and the substantia nigra pars reticulata. To elucidate the functional role of mGluR1 in the control of pallidal neuron activity, extracellular unit recordings combined with intrapallidal microinjections of mGluR1-related agents were then performed in normal and parkinsonian monkeys. In normal awake conditions, the spontaneous firing rates of neurons in the pallidal complex were increased by DHPG, a selective agonist of group I mGluRs, whereas they were decreased by AIDA, a selective antagonist of group I mGluRs, or LY367385, a selective antagonist of mGluR1. These electrophysiological data strongly indicate that the excitatory mechanism of pallidal neurons by glutamate is mediated at least partly through mGluR1. The effects of the mGluR1-related agents on neuronal firing in the internal pallidal segment became rather obscure after MPTP treatment. Our results suggest that the specific down-regulation of pallidal and nigral mGluR1alpha in the parkinsonian state may exert a compensatory action to reverse the overactivity of the subthalamic nucleus-derived glutamatergic input that is generated in the disease.

Role of ionotropic glutamatergic and GABAergic inputs on the firing activity of neurons in the external pallidum in awake monkeys.

The neurons in the external segment of the pallidum (GPe) in awake animals maintain a high level of firing activity. The level and pattern of the activity change with the development of basal ganglia disorders including parkinsonism and hemiballism. The GPe projects to most of the nuclei in the basal ganglia. Thus exploring the mechanisms controlling the firing activity is essential for understanding basal ganglia function in normal and pathological conditions. To explore the role of ionotropic glutamatergic and GABAergic inputs to the GPe, unit recordings combined with local injections of receptor antagonists were performed in awake monkeys. Observations on the effects of local application of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)/kainate antagonist 1,2,3,4-tetrahydro-6-nitro-2, 3-dioxo-benzo[f]quinoxaline-7-sulfonamide, the N-methyl-D-aspartic acid (NMDA) antagonist 3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid, and the GABAA antagonist gabazine as well as the effects of muscimol blockade of the subthalamic nucleus on the spontaneous firing rate, firing patterns, and cortical stimulation induced responses in the GPe suggested the following: sustained glutamatergic and GABAergic inputs control the level of the spontaneous firing of GPe neurons; both AMPA/kainate and NMDA receptors are activated by glutamatergic inputs; some GPe neurons receive glutamatergic inputs originating from areas other than the subthalamic nucleus; no GPe neurons became silent after a combined application of glutamate and GABA antagonists, suggesting that GPe neurons have intrinsic properties or nonionotropic glutamatergic tonic inputs that sustain a fast oscillatory firing or a combination of a fast and a slow oscillatory firing in GPe neurons.

Organization of prefrontal outflow toward frontal motor-related areas in macaque monkeys.

Linkage between the prefrontal cortex and the primary motor cortex is mediated by nonprimary motor-related areas of the frontal lobe. In an attempt to analyse the organization of the prefrontal outflow from area 46 toward the frontal motor-related areas, we investigated the pattern of projections involving the higher-order motor-related areas, such as the presupplementary motor area (pre-SMA) and the rostral cingulate motor area (CMAr). Tracer injections were made into these motor-related areas (their forelimb representation) on the medial wall that had been identified electrophysiologically. The following data were obtained from a series of tract-tracing experiments in Japanese monkeys. (i) Only a few neurons in area 46 were retrogradely labelled from the pre-SMA and CMAr; (ii) terminal labelling from area 46 occurred sparsely in the pre-SMA and CMAr; (iii) a dual labelling technique revealed that the sites of overlap of anterograde labelling from area 46 and retrograde labelling from the pre-SMA and CMAr were evident in the rostral parts of the dorsal and ventral premotor cortices (PMdr and PMvr); (iv) and tracer injections into the PMdr produced neuronal cell labelling in area 46 and terminal labelling in the pre-SMA and CMAr. The present results indicate that a large portion of the prefrontal signals from area 46 is not directly conveyed to the pre-SMA and CMAr, but rather indirectly by way of the PMdr and PMvr. This suggests that area 46 exerts its major influence on the cortical motor system via these premotor areas.

Aldose reductase inhibitors from the leaves of Myrciaria dubia (H. B. & K.) McVaugh.

Ellagic acid (1) and its two derivatives, 4-O-methylellagic acid (2) and 4-(alpha-rhamnopyranosyl)ellagic acid (3) were isolated as inhibitors of aldose reductase (AR) from Myrciaria dubia (H. B. & K.) McVaugh. Compound 2 was the first isolated from the nature. Compound 3 showed the strongest inhibition against human recombinant AR (HRAR) and rat lens AR (RLAR). Inhibitory activity of compound 3 against HRAR (IC50 value = 4.1 x 10(-8) M) was 60 times more than that of quercetin (2.5 x 10(-6) M). The type of inhibition against HRAR was uncompetitive.

Alteration of medullary dorsal horn neuronal activity following inferior alveolar nerve transection in rats.

The effects of inferior alveolar nerve (IAN) transection on escape behavior and MDH neuronal activity to noxious and nonnoxious stimulation of the face were precisely analyzed. Relative thresholds for escape from mechanical stimulation applied to the whisker pad area ipsilateral to the transection were significantly lower than that for the contralateral and sham-operated whisker pad until 28 days after the transection, then returned to the preoperative level at 40 days after transection. A total of 540 neurons were recorded from the medullary dorsal horn (MDH) of the nontreated naive rats [low-threshold mechanoreceptive (LTM), 27; wide dynamic range (WDR), 31; nociceptive specific (NS), 11] and sham-operated rats with skin incision (LTM, 34; WDR, 30; NS, 23) and from the ipsilateral (LTM, 82; WDR, 82; NS, 31) and contralateral MDH relative to the IAN transection (LTM, 77; WDR, 82; NS, 33). The electrophysiological properties of these neurons were precisely analyzed. Background activity of WDR neurons on the ipsilateral side relative to the transection was significantly increased at 2-14 days after the operation as compared with that of naive rats. Innocuous and noxious mechanical-evoked responses of LTM and WDR neurons were significantly enhanced at 2-14 days after IAN transection. The mean area of the receptive fields of WDR neurons was significantly larger on the ipsilateral MDH at 2-7 days after transection than that of naive rats. We could not observe any modulation of thermal responses of WDR and NS neurons following IAN transection. Also, no MDH neurons were significantly affected in the rats with sham operations. The present findings suggest that the increment of neuronal activity of WDR neurons in the MDH following IAN transection may play an important role in the development of the mechano-allodynia induced in the area adjacent to the area innervated by the injured nerve.

Aldose reductase inhibitors from the fruits of Caesalpinia ferrea Mart.

Aldose reductase inhibitors were isolated from an extract of the dry fruits of Caesalpinia ferrea Mart. (Leguminosae). Compound 2 was identified as ellagic acid by comparison with a reference sample. The structure of compound 1 was elucidated as 2-(2,3,6-trihydroxy-4-carboxyphenyl) ellagic acid on the basis of spectral evidence, especially 2D-NMR data (HMQC, HMBC and NOESY). These two compounds inhibited aldose reductase in a non-competitive manner.

Antioxidative activity of carbazoles from Murraya koenigii leaves.

The antioxidative properties of the leaves extracts of Murraya koenigii using different solvents were evaluated based on the oil stability index (OSI) together with their radical scavenging ability against 1-1-diphenyl-2-picrylhydrazyl (DPPH). The methylene chloride (CH(2)Cl(2)) extract and the ethyl acetate (EtOAc) soluble fraction of the 70% acetone extract significantly prolonged the OSI values comparable to those of alpha-tocopherol and BHT. Five carbazole alkaloids were isolated from the CH(2)Cl(2) extract and their structures were identified to be euchrestine B (1), bismurrayafoline E (2), mahanine (3), mahanimbicine (4), and mahanimbine (5) based on (1)H and (13)C NMR and mass (MS) spectral data. The OSI value of carbazoles at 110 degrees C decreased in the order 1 and 3 > alpha-tocopherol > BHT > 2 > 4, 5 and control. It is assumed that compounds 1 and 3 contributed to the high OSI value of the CH(2)Cl(2) extract of M. koenigii. The DPPH radical scavenging activity for these carbazoles was in the order ascorbic acid > 2 > 1, 3 and alpha-tocopherol > BHT > 4 and 5.

Simple isoquinoline and benzylisoquinoline alkaloids as potential antimicrobial, antimalarial, cytotoxic, and anti-HIV agents.

Twenty-six simple isoquinolines and 21 benzylisoquinolines were tested for antimicrobial, antimalarial, cytotoxic, and anti-HIV activities. Some simple isoquinoline alkaloids were significantly active in each assay, and may be useful as lead compounds for developing potential chemotherapeutic agents. These compounds include 13 (antimicrobial), 25, 26, and 42 (antimalarial), 13 and 25 (cytotoxic), and 28 and 29 (anti-HIV). A quaternary nitrogen atom of isoquinolium or dihydroisoquinolinium type may contribute to enhanced potency in the first three types of activities. In contrast, anti-HIV activity was found with tetrahydroisoquinoline and 6,7-dihydroxyisoquinolium salts.

Antitumor agents 210. Synthesis and evaluation of taxoid-epipodophyllotoxin conjugates as novel cytotoxic agents.

Five compounds composed of a taxoid (paclitaxel or cephalomannine) and a 4'-O-demethyl epipodophyllotoxin derivative joined by an imine linkage were prepared and evaluated as cytotoxic agents and inhibitors of mammalian DNA topoisomerase II. Compounds 12 and 14-16 exhibited comparable or better activity than the unconjugated epipodophyllotoxin derivatives in most tumor cell lines, and 12, 15, and 16 also showed enhanced activity against paclitaxel-resistant cells. Compound 13, which contains an epipodophyllotoxin moiety at both the taxoid 2' and 7 positions, did not stimulate protein-DNA breaks, but was 2-fold more potent than 12 and 15 and comparable to GL-331 in the topo II inhibitory assay.

Cytotoxic pheophorbide-related compounds from Clerodendrum calamitosum and C. cyrtophyllum.

Three pheophorbide-related compounds (1-3) were isolated from the leaves and stems of Clerodendrum calamitosum. The methyl ester of 3 (6) and the known (10S)-hydroxypheophytin a (7) also were isolated from leaves of the related plant Clerodendrum cyrtophyllum. Compounds 1 and 6 were isolated for the first time as naturally occurring products from a plant source. All structures were elucidated by detailed spectroscopic analysis. Biological evaluation showed that 1 and 2 exhibited strong cytotoxicity against human lung carcinoma (A549), ileocecal carcinoma (HCT-8), kidney carcinoma (CAKI-1), breast adenocarcinoma (MCF-7), malignant melanoma (SK-MEL-2), ovarian carcinoma (1A9), and epidermoid carcinoma of the nasopharynx (KB), and its etoposide- (KB-7d), vincristine- (KB-VCR), and camptothecin-resistant (KB-CPT) subclones. Compound 3 was less cytotoxic than 1 and 2. Compounds 4-6, the methyl esters of 1-3, showed strongly increased cytotoxicity compared with the parent acids. Interestingly, 6 was the most active derivative among these compounds. Compound 7 was inactive.

Anti-HIV and cytotoxic activities of Ru(II)/Ru(III) polypyridyl complexes containing 2,6-(2'-benzimidazolyl)-pyridine/chalcone as co-ligand.

Ru(II)/Ru(III) polypyridyl complexes containing 2,6-(2'-benzimidazolyl)-pyridine or chalcone as co-ligands were synthesized and characterized previously (Mishra, L.; Sinha, R. Indian J. Chem., Sec. A 2001, in press. Mishra, L.; Sinha, R. Indian J. Chem., Sec. A, 39A, 2000, 1131). Their interaction with aqueous buffered calf thymus DNA was measured. (Novakova, O.; Kasparkova, J.; Vrana, O.; van Vliet, P. M., Reedijk, J.; Brabec, V., Biochem. 34, 1995, 12369 and these results prompted additional screening for anti-HIV (human immunodeficiency virus) activity against DNA replication in H9 lymphocytes and cytotoxic activity against eight tumor cell lines. The most active compounds were 17 in the former assay (EC(50) < 0.1 microg/mL and TI > 23.1) and 3, 8, 10, and 14 in the latter assay, especially selectively against the 1A9 ovarian cancer cell line (IC(50) = 4.1, 3.8, 3.6, and 2.5 microg/mL, respectively).

Antitumor agents. 207. Design, synthesis, and biological testing of 4beta-anilino-2-fluoro-4'-demethylpodophyllotoxin analogues as cytotoxic and antiviral agents.

2-Fluoropodophyllotoxin (11) and several 4beta-anilino-2-fluoro-4'-O-demethyl analogues were synthesized and evaluated in both antineoplastic and antiviral assays. These compounds were moderately active against some cancer cell lines, but they were less active than the corresponding nonfluorinated analogues. Compound 11 exhibited the best activity against KB carcinoma with a GI(50) of approximately 30 nM. Most compounds exhibited moderate activity against HCMV with ID(50) and ID(90) values in the range of 1 microM and 4 microM, respectively. Both 9 and 11 showed an unusual 10-fold selectivity for HSV-2 compared to HSV-1.