Hydrogenation of Formate Species Using Atomic Hydrogen on a Cu(111) Model Catalyst.

The reaction mechanism of the CH3OH synthesis by the hydrogenation of CO2 on Cu catalysts is unclear because of the challenge in experimentally detecting reaction intermediates formed by the hydrogenation of adsorbed formate (HCOOa). Thus, the objective of this study is to clarify the reaction mechanism of the CH3OH synthesis by establishing the kinetic natures of intermediates formed by the hydrogenation of adsorbed HCOOa on Cu(111). We exposed HCOOa on Cu(111) to atomic hydrogen at low temperatures of 200-250 K and observed the species using infrared reflection absorption (IRA) spectroscopy and temperature-programmed desorption (TPD) studies. In the IRA spectra, a new peak was observed upon the exposure of HCOOa on Cu(111) to atomic hydrogen at 200 K and was assigned to the adsorbed dioxymethylene (H2COOa) species. The intensity of the new peak gradually decreased with heating from 200 to 290 K, whereas the IR peaks representing HCOOa species increased correspondingly. In addition, small amounts of formaldehyde (HCHO), which were formed by the exposure of HCOOa species to atomic hydrogen, were detected in the TPD studies. Therefore, H2COOa is formed via hydrogenation by atomic hydrogen, which thermally decomposes at ∼250 K on Cu(111). We propose a potential diagram of the CH3OH synthesis via H2COOa from CO2 on Cu surfaces, with the aid of density functional theory calculations and literature data, in which the hydrogenation of bidentate HCOOa to H2COOa is potentially the rate-determining step and accounts for the apparent activation energy of the methanol synthesis from CO2 on Cu surfaces.

Role of Intermolecular Interactions in the Catalytic Reaction of Formic Acid on Cu(111).

Formic acid (HCOOH) can be catalytically decomposed into H2 and CO2 and is a promising hydrogen storage material. As H2 production catalysts, Cu surfaces allow selective HCOOH decarboxylation; however, the on-surface HCOOH decomposition reaction pathway remains controversial. In this study, the temperature dependence of the HCOOH/Cu(111) adsorption structures is elucidated by scanning tunneling microscopy and non-contact atomic force microscopy, establishing the adsorbate chemical species using density functional theory. 2D HCOOH islands at 80 K, linear chains of HCOOH and monodentate formate at 150 K, chain-like assemblies of monodentate and bidentate formate at 200 K, and bidentate formate clusters at 300 K are observed. At each temperature, the adsorbates experience attractive interactions among themselves. Such aggregation stabilizes them against desorption and decomposition. Thus, accurate evaluation of intermolecular interactions is essential to understand catalytic reactivity.

A flat-lying dimer as a key intermediate in NO reduction on Cu(100).

The reaction of nitric oxide (NO) on Cu(100) is studied by scanning tunneling microscopy, electron energy loss spectroscopy and density functional theory calculations. The NO molecules adsorb mainly as monomers at 64 K, and react and dissociate to yield oxygen atoms on the surface at ∼70 K. The temperature required for the dissociation is significantly low for Cu(100), compared to those for Cu(111) and Cu(110). The minimum energy pathway of the reaction is via (NO)2 formation, which converts into a flat-lying ONNO and then dissociates into N2O and O with a considerably low activation energy. We propose that the formation of (NO)2 and flat-lying ONNO is the key to the exceptionally high reactivity of NO on Cu(100).

Manipulable Metal Catalyst for Nanographene Synthesis.

Performing bottom-up synthesis by using molecules adsorbed on a surface is an effective method to yield functional polycyclic aromatic hydrocarbons (PAHs) and nanocarbon materials. The intramolecular cyclodehydrogenation of hydrocarbons is a critical process in this synthesis; however, thus far, its elementary steps have not been elucidated thoroughly. In this study, we utilize the metal tip of a low-temperature noncontact atomic force microscope as a manipulable metal surface to locally activate dehydrogenation for PAH-forming cyclodehydrogenation. This method leads to the dissociation of a H atom of an intermediate to yield the cyclodehydrogenated product in a target-selective and reproducible manner. We demonstrate the metal-tip-catalyzed dehydrogenation for both benzenoid and nonbenzonoid PAHs, suggesting its universal applicability as a catalyst for nanographene synthesis.

Atomic and molecular adsorption on single platinum atom at the graphene edge: A density functional theory study.

We present a density functional theory study of atomic and molecular adsorption on a single Pt atom deposited at the edges of graphene. We investigate geometric and electronic structures of atoms (H, C, N, and O) and molecules (O2, CO, OH, NO, H2O, and OOH) on a variety of Pt deposited graphene edges and compare the adsorption states with those on a Pt(111) surface and on a Pt single atom. Furthermore, using the calculated adsorption energy and simple kinetic models, the catalytic activities of a Pt single-atom catalyst for the oxygen reduction reaction and CO oxidation are discussed.

Big Insulin-like Growth Factor 2-Producing Tumor in a Hypoglycemic Dog.

A 10-year-old female Papillon dog that had previously developed a mammary tumor was admitted for treatment of a hypoglycemic attack. Blood examination showed severe hypoglycemia and decreased blood insulin concentration. Computed tomography indicated multiple tumors in the cranial and caudal lobes of the right lung. These tumors were resected surgically and diagnosed as pulmonary adenocarcinomas by histopathologic examination. Hypoglycemia was temporarily improved after the resection, but a hypoglycemic event occurred 2 months after the surgery. Immunohistochemistry of the tumor demonstrated the expression of insulin-like growth factor 2 in tumor cells. Western blot analysis revealed the expression of high-molecular-weight (big)-insulin-like growth factor 2 in the tumor region. Insulin-like growth factor 2 mRNA expression was also confirmed in the tumor using reverse transcription-polymerase chain reaction. These findings indicate the diagnosis of non-islet cell tumor-induced hypoglycemia caused by big-insulin-like growth factor 2 produced by the tumor in the dog. This report provides information on differentiating tumors that cause paraneoplastic hypoglycemia.

Van der Waals density functional study of formic acid adsorption and decomposition on Cu(111).

We present a density functional theory study on the adsorption and decomposition mechanisms of monomeric formic acid (HCOOH) on a Cu(111) surface. We used Perdew-Burke-Ernzerhof (PBE) functional, PBE with dispersion correction (PBE-D2), and van der Waals density functionals (vdW-DFs). We found that the adsorption energy of HCOOH by using the PBE functional is smaller than the experimental value, while the PBE-D2 and vdW-DFs give better agreement with experimental results. The activation energies of decomposition calculated by using PBE-D2 and vdW-DFs are lower compared with desorption energies, seemingly in contradiction with experimental findings at room temperature, in which no decomposition of HCOOH on Cu(111) is observed when the surface is exposed to the gas phase HCOOH. We performed the reaction rate analysis based on the first-principles calculations for desorption and decomposition processes to clarify this contradiction. We found that the desorption of monomeric HCOOH is faster than that of its decomposition rate at room temperature because of a much larger pre-exponential factor. Thus, no decomposition of monomeric HCOOH should take place at room temperature. Our analysis revealed the competition between desorption and decomposition processes of HCOOH.

Enhancement of CO2 adsorption on oxygen-functionalized epitaxial graphene surface under near-ambient conditions.

The functionalization of graphene is important in practical applications of graphene, such as in catalysts. However, the experimental study of the interactions of adsorbed molecules with functionalized graphene is difficult under ambient conditions at which catalysts are operated. Here, the adsorption of CO2 on an oxygen-functionalized epitaxial graphene surface was studied under near-ambient conditions using ambient-pressure X-ray photoelectron spectroscopy (AP-XPS). The oxygen-functionalization of graphene is achieved in situ by the photo-induced dissociation of CO2 with X-rays on graphene in a CO2 gas atmosphere. The oxygen species on the graphene surface is identified as the epoxy group by XPS binding energies and thermal stability. Under near-ambient conditions of 1.6 mbar CO2 gas pressure and 175 K sample temperature, CO2 molecules are not adsorbed on the pristine graphene, but are adsorbed on the oxygen-functionalized graphene surface. The increase in the adsorption energy of CO2 on the oxygen-functionalized graphene surface is supported by first-principles calculations with the van der Waals density functional (vdW-DF) method. The adsorption of CO2 on the oxygen-functionalized graphene surface is enhanced by both the electrostatic interactions between the CO2 and the epoxy group and the vdW interactions between the CO2 and graphene. The detailed understanding of the interaction between CO2 and the oxygen-functionalized graphene surface obtained in this study may assist in developing guidelines for designing novel graphene-based catalysts.

Molecular cloning and characterization of the family of feline leucine-rich glioma-inactivated (LGI) genes, and mutational analysis in familial spontaneous epileptic cats.

BACKGROUND: Leucine-rich glioma-inactivated (LGI) proteins play a critical role in synaptic transmission. Dysfunction of these genes and encoded proteins is associated with neurological disorders such as genetic epilepsy or autoimmune limbic encephalitis in animals and human. Familial spontaneous epileptic cats (FSECs) are the only feline strain and animal model of familial temporal lobe epilepsy. The seizure semiology of FSECs comprises recurrent limbic seizures with or without evolution into generalized epileptic seizures, while cats with antibodies against voltage-gated potassium channel complexed/LGI1 show limbic encephalitis and recurrent limbic seizures. However, it remains unclear whether the genetics underlying FSECs are associated with LGI family genes. In the present study, we cloned and characterized the feline LGI1-4 genes and examined their association with FSECs. Conventional PCR techniques were performed for cloning and mutational analysis. Characterization was predicted using bioinformatics software. RESULTS: The cDNAs of feline LGI1-4 contained 1674-bp, 1650-bp, 1647-bp, and 1617-bp open reading frames, respectively, and encoded proteins comprising 557, 549, 548, and 538 amino acid residues, respectively. The feline LGI1-4 putative protein sequences showed high homology with Homo sapiens, Canis familiaris, Bos taurus, Sus scrofa, and Equus caballus (92%-100%). Mutational analysis in 8 FSECs and 8 controls for LGI family genes revealed 3 non-synonymous and 14 synonymous single nucleotide polymorphisms in the coding region. Only one non-synonymous single nucleotide polymorphism in LGI4 was found in 3 out of 8 FSECs. Using three separate computational tools, this mutation was not predicted to be disease causing. No co-segregation of the disease was found with any variant. CONCLUSIONS: We cloned the cDNAs of the four feline LGI genes, analyzed the amino acid sequences, and revealed that epilepsy in FSEC is not a monogenic disorder associated with LGI genes.

Image potential states from the van der Waals density functional.

The image potential state is one of the fundamental surface electronic states and has a great relevance to many surface phenomena, but its accurate description is a great challenge for the semilocal density functional. Here, we use the nonlocal van der Waals density functional to describe the image potential states of graphene, graphite, and carbon nanotubes. We found that although it does not yield the correct image potential outside the surface, the van der Waals density functional improves the description of image potential states because of the nonlocal correlation potential. Our study demonstrates the usefulness of the van der Waals density functional to study the surface electronic properties.

CO2 adsorption on the copper surfaces: van der Waals density functional and TPD studies.

We investigated the adsorption of CO2 on the flat, stepped, and kinked copper surfaces from density functional theory calculations as well as the temperature programmed desorption and X-ray photoelectron spectroscopy. Several exchange-correlation functionals have been considered to characterize CO2 adsorption on the copper surfaces. We used the van der Waals density functionals (vdW-DFs), i.e., the original vdW-DF (vdW-DF1), optB86b-vdW, and rev-vdW-DF2, as well as the Perdew-Burke-Ernzerhof (PBE) with dispersion correction (PBE-D2). We have found that vdW-DF1 and rev-vdW-DF2 functionals slightly underestimate the adsorption energy, while PBE-D2 and optB86b-vdW functionals give better agreement with the experimental estimation for CO2 on Cu(111). The calculated CO2 adsorption energies on the flat, stepped, and kinked Cu surfaces are 20-27 kJ/mol, which are compatible with the general notion of physisorbed species on solid surfaces. Our results provide a useful insight into appropriate vdW functionals for further investigation of related CO2 activation on Cu surfaces such as methanol synthesis and higher alcohol production.

Comparisons among MRI signs, apparent diffusion coefficient, and fractional anisotropy in dogs with a solitary intracranial meningioma or histiocytic sarcoma.

Although MRI has become widely used in small animal practice, little is known about the validity of advanced MRI techniques such as diffusion-weighted imaging and diffusion tensor imaging. The aim of this retrospective analytical observational study was to investigate the characteristics of diffusion parameters, that is the apparent diffusion coefficient and fractional anisotropy, in dogs with a solitary intracranial meningioma or histiocytic sarcoma. Dogs were included based on the performance of diffusion MRI and histological confirmation. Statistical analyses were performed to compare apparent diffusion coefficient and fractional anisotropy for the two types of tumor in the intra- and peritumoral regions. Eleven cases with meningioma and six with histiocytic sarcoma satisfied the inclusion criteria. Significant differences in apparent diffusion coefficient value (× 10-3 mm2 /s) between meningioma vs. histiocytic sarcoma were recognized in intratumoral small (1.07 vs. 0.76) and large (1.04 vs. 0.77) regions of interest, in the peritumoral margin (0.93 vs. 1.08), and in the T2 high region (1.21 vs. 1.41). Significant differences in fractional anisotropy values were found in the peritumoral margin (0.29 vs. 0.24) and the T2 high region (0.24 vs. 0.17). The current study identified differences in measurements of apparent diffusion coefficient and fractional anisotropy for meningioma and histiocytic sarcoma in a small sample of dogs. In addition, we observed that all cases of intracranial histiocytic sarcoma showed leptomeningeal enhancement and/or mass formation invading into the sulci in the contrast study. Future studies are needed to determine the sensitivity of these imaging characteristics for differentiating between these tumor types.

Retrospective epidemiological study of canine epilepsy in Japan using the International Veterinary Epilepsy Task Force classification 2015 (2003-2013): etiological distribution, risk factors, survival time, and lifespan.

BACKGROUND: Epilepsy is the most common neurological disease in veterinary practice. However, contrary to human medicine, epilepsy classification in veterinary medicine had not been clearly defined until recently. A number of reports on canine epilepsy have been published, reflecting in part updated proposals from the human epilepsy organization, the International League Against Epilepsy. In 2015, the International Veterinary Epilepsy Task Force (IVETF) published a consensus report on the classification and definition of canine epilepsy. The purpose of this retrospective study was to investigate the etiological distribution, survival time of dogs with idiopathic epilepsy (IdE) and structural epilepsy (StE), and risk factors for survival time, according to the recently published IVETF classification. We investigated canine cases with epilepsy that were referred to our teaching hospital in Japan during the past 10 years, and which encompassed a different breed population from Western countries. RESULTS: A total of 358 dogs with epilepsy satisfied our etiological study criteria. Of these, 172 dogs (48 %) were classified as IdE and 76 dogs (21 %) as StE. Of these dogs, 100 dogs (consisting of 65 with IdE and 35 with StE) were included in our survival study. Median survival time from the initial epileptic seizure in dogs with IdE and StE was 10.4 and 4.5 years, respectively. Median lifespan of dogs with IdE and StE was 13.5 and 10.9 years, respectively. Multivariable analysis demonstrated that risk factors for survival time in IdE were high seizure frequency (≥0.3 seizures/month) and focal epileptic seizures. CONCLUSIONS: Focal epileptic seizures were identified as a risk factor for survival time in IdE. Clinicians should carefully differentiate seizure type as it is difficult to identify focal epileptic seizures. With good seizure control, dogs with IdE can survive for nearly the same lifespan as the general dog population. Our results using the IVETF classification are similar to previous studies, although some features were noted in our Japanese canine population (which was composed of mainly small-breed dogs), including a longer lifespan in dogs with epilepsy and a larger percentage of meningoencephalomyelitis of unknown origin in dogs with StE.

Dissociative adsorption of CO2 on flat, stepped, and kinked Cu surfaces.

We studied the dissociative adsorption of CO2 to CO + O on the Cu(111), Cu(221), Cu(211), and Cu(11 5 9) surfaces by using state-of-the-art density functional theory (DFT) within a generalized gradient approximation (GGA) and van der Waals density functional (vdW-DF) calculations. The activation energy for CO2 dissociation on the flat Cu(111) surface is 1.33 eV. The activation energies on stepped and kinked surfaces are 1.06 eV, 0.67 eV, and 1.02 eV for the Cu(221), Cu(211), and Cu(11 5 9) surfaces, respectively. Even though the activation energy is 0.66 eV lower on the stepped Cu(211) surface than on the flat Cu(111) surface, we conclude that CO2 does not dissociate on "ideal" flat, stepped, or kinked Cu surfaces at low temperature. We attribute the discrepancy between our theoretical results and experimentally observed CO2 dissociation on stepped Cu surfaces below 150 K to other factors such as effects of Cu adatoms, gas phase or condensed CO2 molecules, or interaction with other gas phase molecules.

Investigation of the effect and availability of ketamine on electroencephalography in cats with temporal lobe epilepsy.

In recent years, electroencephalography (EEG) in veterinary medicine has become important not only in the diagnosis of epilepsy, but also in determining the epileptogenic focus. In cats, sedation and immobilization, usually with medetomidine or dexmedetomidine, are necessary to place the electrodes and to obtain stable scalp EEG recordings. In this study, we hypothesized that, for cats with temporal lobe epilepsy (TLE), ketamine, a sedative/anesthetic and N-methyl-D-aspartate (NMDA) antagonist that activates the limbic system and is also used to treat refractory status epilepticus in dogs, would induce sufficient sedation and immobilization for EEG, as well as induce interictal epileptiform discharges (IEDs) that are more pronounced than those induced with medetomidine. We obtained EEG recordings from TLE cats and healthy cats administered either ketamine or medetomidine alone (study 1) or ketamine after medetomidine sedation (study 2). In study 1, the frequency of IEDs showed no statistically significant difference between ketamine and medetomidine in both TLE and healthy cats. Seizures were observed in 75% (9/12) cats of the TLE group with ketamine alone. When ketamine was administered after sedation with medetomidine (study 2), 3/18 cats in the TLE group developed generalized tonic-clonic seizure and 1/18 cats showed subclinical seizure activity. However, no seizures were observed in all healthy cats in both study 1 and study 2. Slow wave activity at 2-4 Hz was observed in many individuals after ketamine administration regardless studies and groups, and quantitative analysis in study 2 showed a trend toward increased delta band activities in both groups. While there was no significant difference in the count of IEDs between medetomidine and ketamine, ketamine caused seizures in cats with TLE similar to their habitual seizure type and with a higher seizure frequency. Our results suggest that ketamine may activate epileptiform discharges during EEG recordings. However, caution should be used for cats with TLE.

Pulmonary solid adenocarcinoma in a dog.

A 12-year-old castrated male Beagle dog presented with a 1-month history of progressive loss of appetite and cough. One month after the initial visit, a detailed clinical examination was performed due to weight loss and persistent cough. Computed tomography demonstrated diffuse opacification of the entire right lung and cranial lobe of the left lung. Samples of the pulmonary lesions obtained by fine-needle aspiration (FNA) were highly cellular with scattered and clustered foci of large round cells, suggestive of a round cell tumour. Ten days after the FNA, the dog was euthanized due to decreased activity and severe respiratory symptoms. At necropsy, enlargement of the entire right lung and cranial lobe of the left lung was seen. The external and cut surfaces of the lungs were homogeneously grey-white. Histopathological examination of sections of the right lung and the cranial lobe of the left lung revealed proliferation of large round or polygonal neoplastic cells arranged in nests of variable size separated by a thin fibrous stroma. Neoplastic cells were immunopositive for cytokeratin and thyroid transcription factor-1 but negative for vimentin, CD204, chromogranin A and synaptophysin. On the basis of these findings, the tumour was diagnosed as pulmonary solid adenocarcinoma.

Age-related brain atrophy in cats without apparent neurological and behavioral signs using voxel-based morphometry.

Introduction: Brain atrophy is observed with aging and may cause cognitive decline or dysfunction. Aging cats may demonstrate behavioral changes related to cognitive dysfunction. In the clinical veterinary field, although the conventional region of interest method by manual or semiauto tracing on magnetic resonance imaging is used to detect atrophy of regional structures, such as the hippocampus, it is difficult to assess atrophy globally. Voxel-based morphometry (VBM) has been developed to detect global and regional abnormalities in humans. The purpose of the present study investigates whether the feline brain volume decreases with aging using VBM analysis. Materials: A total of 65 cats, aged 17-200 months, without apparent neurological and behavioral signs were included in the statistical analysis. Results: We observed that the gray matter in the bilateral parietal lobes was decreased significantly with aging. The regions that showed decreased volume included the right postcruciate, cingulate gyrus, rostral suprasylvian/ectosylvian gyri, and the left postcruciate gyrus. No significant reduction in white matter was observed. Together, our results show that age-related brain atrophy can be detected using VBM analysis. Discussion: The age-related atrophy of the parietal cortex may not cause neurological and behavioral signs in cats. Therefore, veterinarians should consider age when assessing the relation between morphometric and functional abnormalities of the parietal cortex in cats.

Successful treatment of feline hyperadrenocorticism with pituitary macroadenoma using radiation therapy: a case study.

A 10-year-old castrated male cat showing behavioral (irritation, prowling, and tumbling) and cutaneous abnormalities such as dermal fragility was diagnosed as hyperadrenocorticism with pituitary macroadenoma, concurrent with insulin dependent diabetes mellitus. Pituitary enlargement (18.0 mm) was observed during magnetic resonance imaging. High endogenous adrenocorticotropic hormone levels (>2,500 pg/ml) were also observed. Although trilostane treatment (5-10 mg/head, daily) was commenced, the clinical signs did not disappear. Insulin and trilostane treatment were discontinued on day 86 after first day of radiation therapy (4 Gy/12 fractions). After radiation therapy, a decreased pituitary tumor size (10.7 mm) was observed on day 301; neurological and dermatological signs exhibited remission. Radiation therapy is the treatment of choice for feline hyperadrenocorticism with pituitary macroadenoma with neurological signs.

Skeletal radiographic manifestations of GM2 gangliosidosis variant 0 (Sandhoff disease) in two Japanese domestic cats.

CASE SERIES SUMMARY: Two Japanese domestic cats with GM2 gangliosidosis variant 0, diagnosed at different times, are included in this case series. Both cats were diagnosed by genetic analysis and had the HEXB:c.667C>T pathogenic genetic variant, which have been previously reported in Japanese domestic cats with GM2 gangliosidosis variant 0. Clinical signs and the identification of vacuolation in circulating lymphocytes were consistent with those in previous reports of feline GM2 gangliosidosis variant 0. Radiography showed that both cases had similar skeletal radiographic manifestations, which has not been previously reported in Japanese domestic cats with GM2 gangliosidosis variant 0. Radiographic findings included abnormally shaped vertebral bodies, obscure or irregular endplates (both of which were seen especially in the cervical and thoracic vertebrae), generalised osteopenia and new bone proliferation around articular facets. RELEVANCE AND NOVEL INFORMATION: To the best of our knowledge, this is the first report to present the skeletal radiographic abnormalities of Japanese domestic cats with GM2 gangliosidosis variant 0 caused by the HEXB:c.667C>T pathogenic genetic variant. Furthermore, together with a report published in 2015 on the radiographic findings of feline GM2 gangliosidosis variant 0 caused by another pathogenic genetic variant, this report suggests that these findings may be indicators of feline GM2 gangliosidosis variant 0. The easily obtained radiographic findings described in this report may be useful as a finding suggestive of feline GM2 gangliosidosis variant 0, in addition to the cytological finding of the vacuolated cells. The report emphasises the utility of radiography for diagnosis of cases with suspected progressive neurodegenerative diseases.

Effect of an Insulation Device in Preventing Hypothermia during Magnetic Resonance Imaging Examinations for Dogs and Cats under General Anesthesia.

Dogs and cats under general anesthesia may develop hypothermia. When performing a magnetic resonance imaging (MRI) examination, it is not possible to place a magnetic material in the MRI room, and MRI equipment requires a low room temperature. This study investigated the effectiveness of a heat insulating device that prevented hypothermia during MRI examinations in dogs and cats. The animals that underwent MRI examinations under general anesthesia were divided into control groups (no covering) and heat insulating groups (wearing bubble wrap and down cloth blankets), and their body temperatures were measured before and after the MRI examinations. The changes in body temperatures were as follows: control dogs (n = 17), median of -1.0 (from -2.5 to 0.3) °C; heat insulated dogs (n = 7), -0.3 (from -0.8 to 0.2) °C; control cats (n = 14), -1.85 (from -2.7 to -0.6) °C; and heat insulated cats (n = 12), -0.8 (from -1.5 to -0.1) °C. These results revealed that the bubble wrap and down cloth blanket significantly prevented hypothermia and heat loss from the body surface during MRI examinations of dogs and cats.