鉄道車両の種類を考慮した車両運用計画問題

電気通信大学修士2019鉄道路線のダイヤグラムが与えられたとき、ダイヤグラムに存在する全ての列車に鉄道車両の編成を割り当てることを考える。鉄道車両の列車への割り当てを決定することを編成の運用を決定するといい、ダイヤグラムに存在する全ての列車に編成に割り当てられるような編成数の最小値と、その時の各編成の運用を決定する問題を車両運用計画問題という。 　車両運用計画問題を扱う手法として、次の2つが挙げられる。 　1つは、列車の接続を有向グラフで表現して、そのグラフの上のハミルトン閉路として編成の運用を表現し、グラフに適当な重みを与えて、使用した辺の重みの総和を最小化するハミルトン閉路を発見することを試みるものである。もう1つは、列車の接続を閉路のない有向グラフとして表現し、そのグラフの上のパスとして運用を表現し、パスの本数を最小化することを試みるものである。 　また、鉄道車両の検査を考慮するアルゴリズムが提案されているが、そのアルゴリズムを実行するためには、最初にダイヤグラムに存在している全列車に編成を割り当てる時の編成数の最小値を求めて、必要な検査回数を計算する必要がある。 　そこで、本論文では、車両運用計画問題の整数計画問題としての定式化の他、ダイヤグラムに存在する列車に複数の種別が存在し、種別ごとに車両の種類を変更しなければならない場合並びに、路線の一部区間に電化方式等の、割り当て可能な車両の種類が制限されるような場合の2つのケースについて整数計画問題として定式化を行った。更に、路線に分岐が存在する場合並びに路線がループしている場合にも対応するモデルを構成した。各々のケースに対する定式化をPython3と数理最適化ソルバーGurobiを用いて実装し、実際の時刻表データを与えて、実行時間の様子を観察、評価した。データセットとして用意した中で、列車数が400程度のものは計算を1時間程度で終了することが明らかになったが、列車数が1100程度となる大規模なものでは1週間では計算が終了しないことも明らかとなった。thesi

Serum Concentrations of Imidazole Dipeptides and Serum Amyloid A in a Bottlenose Dolphin (Tursiops truncatus) with Rhabdomyolysis: Potential Biomarkers for Muscular Damage

Imidazole dipeptides (IDPs), including anserine, carnosine, and balenine, are predominantly found in the skeletal muscles of vertebrates. Balenine is the major IDP in cetaceans. Serum amyloid A (SAA) is an acute phase protein released in response to damage or injury in various tissues, including skeletal muscles. A captive bottlenose dolphin (Tursiops truncatus) died due to rhabdomyolysis and subsequent acute kidney injury that probably originated from accidental muscle trauma. In this study, concentrations of IDPs and SAA were measured using stored serum collected from the affected dolphin with intermittent continuous damage of skeletal muscles to demonstrate the pathological relevance of these parameters and their usefulness as biomarkers for muscle damage in dolphins. The IDP concentration was measured using the high-performance liquid chromatography-ultraviolet method. The SAA concentration was measured using an enzyme-linked immunosorbent assay (ELISA) specific to dolphin SAA and a latex turbidimetric immunoassay (LTI) specific to human SAA. Herein, the IDP concentration was altered similarly to serum muscular enzymes, including creatinine kinase (CK) and aspartate aminotransferase (AST). However, IDP concentrations were elevated one day earlier than CK and AST levels at disease onset. Furthermore, IDP concentrations were similarly altered when assessed using both ELISA- and LTI-SAAs, and the change in IDP concentration coincided with that in LTI-SAA based on the statistical analysis. These data suggest that IDP concentration could detect muscle damage and injury, including necrosis and inflammation, in dolphins

Histopathology of nasopharyngeal and palatine tonsils in Japanese black calves naturally infected with Mycoplasma bovis

Mycoplasma bovis (M. bovis) is an important bacterium in the bovine respiratory disease complex (BRDC), which causes significant economic losses. The nasopharyngeal and palatine tonsils are mucosal-associated lymphoid tissue components that are the initial barrier to respiratory pathogens. In the present study, we investigated 5 pneumonic Japanese black and 3 control calves (2 Japanese black and 1 Holstein). The localization of M. bovis in the nasopharyngeal, palatine tonsils, and lungs was examined using nested and multiplex polymerase chain reaction (PCR), histopathology, and in situ hybridization (ISH) techniques. Nested PCR revealed that all examined tissues from all pneumonic calves were positive for M. bovis infection, but not the control. Histopathology revealed suppurative nasopharyngeal tonsillitis and palatine tonsillar cryptitis in all cases. Surprisingly, prominent histologic changes were observed in the palatine tonsils but not in the nasopharyngeal tonsils. Necrotizing suppurative bronchopneumonia was observed in 4 pneumonic calves. In ISH analysis, positive hybridization signals adherent to and/or within the surface epithelium of nasopharyngeal tonsils and crypt epithelium of nasopharyngeal and palatine tonsils were observed. Additionally, these signals were seen in the palatine tonsillar cryptic detritus. In the lungs, ISH signals were observed in necrotic areas, the bronchial epithelium, and pulmonary inflammatory exudate. These findings suggest that the nasopharyngeal and palatine tonsils are the primary sites of M. bovis infection. Also, M. bovis can colonize the detritus in the crypts of the palatine tonsils of the pneumonic animals

Generation of a Porcine Cell Line Stably Expressing Pig TMPRSS2 for Efficient Isolation of Swine Influenza Virus

Pigs are important animals for meat production but can carry several zoonotic diseases, including the Japanese encephalitis virus, Nipah virus, and influenza viruses. Several Orthomyxoviridae and Coronavirinae respiratory viruses require cleavage of envelope proteins to acquire viral infectivity and consequently, need a host protease or the addition of exogenous trypsin for efficient propagation. Host TMPRSS2 is a key protease responsible for viral cleavage. Stable expression of human TMPRSS2 in African green monkey-derived Vero cells can enhance the porcine epidemic diarrhea virus. However, considering the narrow host tropism of viruses, a porcine cell line expressing pig TMPRSS2 could be optimal for replicating pig-derived viruses. Herein, we generated and evaluated a pig-derived PK-15 cell line stably expressing pig TMPRSS2. This cell line markedly (>1000-fold) and specifically enhanced the growth of influenza viruses. Furthermore, we demonstrated the usefulness of a PK-15 cell line lacking the Stat2 gene with a stable expression of pig TMPRSS2 for efficient virus isolation from clinical samples in the presence of type I interferons. Therefore, PK-15 cells expressing pig TMPRSS2 could be a valuable and promising tool for virus isolation, vaccine production, and virological studies of TMPRSS2-dependent viruses.Citation: Yuri L Tanaka, Maya Shofa, Erika P Butlertanaka, Ahmad Massoud Niazi, Takuya Hirai, Hirohisa Mekata, Akatsuki Saito, Generation of a Porcine Cell Line Stably Expressing Pig TMPRSS2 for Efficient Isolation of Swine Influenza Virus. Pathogens. 2023-12-24, 13(1), 18-18, https://doi.org/10.3390/pathogens1301001

Hepatocellular carcinoma with lung metastasis showing hemochromatosis in an Egyptian fruit bat (Rousettus aegyptiacus)

After an Egyptian fruit bat (Rousettus aegyptiacus) in a zoo became emaciated and died, a necropsy revealed multiple nodules on the liver and lung surfaces. Microscopy revealed that the liver nodules consisted of neoplastic hepatocytes and showed metastasis in the lung lobes. Most of the neoplastic cells in the liver and lung showed positive labeling for HepPar-1, cytokeratin 19, glypican-3, and Ki-67. Hepatocellular degeneration and necrosis were diffuse in the liver parenchyma. Berlin blue staining revealed large amounts of iron in normal and neoplastic cells. Based on these pieces of evidence, this case was diagnosed as hepatocellular carcinoma with hemochromatosis. This is believed to be the first report of hepatocellular carcinoma in an Egyptian fruit bat that has been immunophenotypically examined in detail by pathological examination.Citation: Nijiho Kawaguchi, Naoyuki Fuke, Phawut Nueangphuet, Apisit Pornthummawat, Ahmad Massoud Niazi, Uda Zahli Izzati, Takuya Hirai, Ryoji Yamaguchi, Hepatocellular carcinoma with lung metastasis showing hemochromatosis in an Egyptian fruit bat (Rousettus aegyptiacus). Journal of Veterinary Medical Science. 2024, 86(1), 49-53, https://doi.org/10.1292/jvms.23-015

Pathology of the outbreak of subgenotype 2.5 classical swine fever virus in northern Vietnam

Classical swine fever (CSF) is an endemic disease in southeastern Asia and is one of the most important swine diseases in Vietnam. This study was conducted to characterize the pathology of natural cases of CSF in northern Vietnam in 2018 and their genetic prevalence. A total of 10 representative pigs were collected from four provinces (Hung Yen, Ha Noi, Quang Ninh and Thai Binh) during five outbreaks and examined pathologically. The gross and histopathological findings showed the disease was expressed as the acute or the subacute to chronic form of CSF, depending on the age of the animals. The most consistently observed lesions associated with infection by the classical swine fever virus (CSFV) included lymphoid depletions in tonsils, lymph node and spleen; histiocytic hyperplasia in spleen; cerebral haemorrhage; perivascular cuffing in the brain; renal erythrodiapedesis; urothelial vacuolation and degeneration and interstitial pneumonia. The immunohistochemical findings showed a ubiquitous CSFV antigen mainly in the monocytes/macrophages and in the epithelial and endothelial cells in various organs. CSFV neurotropism was also found in the small neurons of the cerebrum and the ganglia of the myenteric plexus. Analysis of the full-length envelope protein (E2) genome sequence showed that all strains were genetically clustered into subgenotype 2.5, sharing a nucleotide identity of 94.0%–100.00%. Based on the results of this study, the strain was categorized as a moderately virulent CSFV.Citation: Izzati UZ, Hoa NT, Lan NT, Diep NV, Fuke N, Hirai T, Yamaguchi R. Pathology of the outbreak of subgenotype 2.5 classical swine fever virus in northern Vietnam. Vet Med Sci. 2021 Jan;7(1):164-174. doi: 10.1002/vms3.339. Epub 2020 Aug 11. PMID: 32781492; PMCID: PMC7840204

A case of ectopic hepatocellular carcinoma around the common bile duct in a dog

A 10-year-old, male neutered pug dog with a history of gallstones was found to have a mass near the caudate lobe of the liver upon ultrasound examination. The mass was red to dark red, multinodular, measuring 3 × 3 × 4 cm and not continuous to the liver. Histopathological examination revealed sheet-like proliferation of polygonal neoplastic cells resembling hepatocytes with mild atypia, and no portal areas were observed. The tumor cells were positive for HepPar-1 and negative for cytokeratin 7. The macrophages decreased in neoplastic lesion compared to normal area. Based on these findings, this case was diagnosed as a hepatocellular carcinoma of ectopic liver origin. This is the second reported case showing the potential for ectopic liver to develop into tumors in dogs

Histopathological findings of the nasopharynx-associated lymphoid tissue of pigs co-infected with porcine circovirus 2 and porcine reproductive and respiratory syndrome virus

Porcine circovirus 2 (PCV2) causes porcine circovirus-associated disease, and co-infection with porcine reproductive and respiratory syndrome virus (PRRSV) severely affects the pig breeding industry. Both viruses target the macrophages in lymphoid tissues. Various porcine pathogens enter via the nasal cavity, and the nasopharynx-associated lymphoid tissue (NALT) acts as the mucosal immune system. However, the pathological analysis has not progressed. This study aimed to histologically examine the NALT of pigs with suspected PCV2 and PRRSV infections. Six pigs were subjected to necropsy, and their NALT, tonsils, and mesenteric lymph nodes were collected. Macrophages, lymphocytic depletion, multinucleated giant cells, intracytoplasmic inclusion bodies, and neutrophil infiltration increased in the NALT. In situ hybridization revealed positive signals for PCV2 in the NALT of all pigs and PRRSV in the NALT of three pigs. PCV2-positive macrophages were mainly identified in the follicles, whereas PRRSV-positive tissues were found primarily around the crypt and directly below the epithelium. Quantitative PCR revealed 108–1010 copies of PCV2 DNA/µL and 102–104 copies of PRRSV DNA/µL in the NALT. Therefore, both PCV2 and PRRSV were detected in the NALT of pigs. In conclusion, the infection and replication of both viruses in the NALT and tonsils may suppress host immunity and promote co-infection with other pathogens.Citation: Toyama K, Hirai T, Sueyoshi M, Zhou Z, Niazi AM, Kawaguchi N, Fuke N, Yamaguchi R. Histopathological findings of the nasopharynx-associated lymphoid tissue of pigs co-infected with porcine circovirus 2 and porcine reproductive and respiratory syndrome virus. J Vet Med Sci. 2022 Nov 14;84(11):1536-1542. doi: 10.1292/jvms.22-0231. Epub 2022 Oct 13. PMID: 36223944; PMCID: PMC9705823

Nine-year seroepidemiological study of severe fever with thrombocytopenia syndrome virus infection in feral horses in Cape Toi, Japan

Severe fever with thrombocytopenia syndrome (SFTS) is a fatal zoonosis caused by ticks in East Asia. As SFTS virus (SFTSV) is maintained between wildlife and ticks, seroepidemiological studies in wildlife are important to understand the behavior of SFTSV in the environment. Miyazaki Prefecture, Japan, is an SFTS-endemic area, and approximately 100 feral horses, called Misaki horses (Equus caballus), inhabit Cape Toi in Miyazaki Prefecture. While these animals are managed in a wild-like manner, their ages are ascertainable due to individual identification. In the present study, we conducted a seroepidemiological survey of SFTSV in Misaki horses between 2015 and 2023. This study aimed to understand SFTSV infection in horses and its transmission to wildlife. A total of 707 samples from 180 feral horses were used to determine the seroprevalence of SFTSV using enzyme-linked immunosorbent assay (ELISA). Neutralization testing was performed on 118 samples. In addition, SFTS viral RNA was detected in ticks from Cape Toi and feral horses. The overall seroprevalence between 2015 and 2023 was 78.5% (555/707). The lowest seroprevalence was 55% (44/80) in 2016 and the highest was 92% (76/83) in 2018. Seroprevalence was significantly affected by age, with 11% (8/71) in those less than one year of age and 96.7% (435/450) in those four years of age and older (p < 0.0001). The concordance between ELISA and neutralization test results was 88.9% (105/118). SFTS viral RNA was not detected in ticks (n = 516) or feral horses. This study demonstrated that horses can be infected with SFTSV and that age is a significant factor in seroprevalence in wildlife. This study provides insights into SFTSV infection not only in horses but also in wildlife in SFTS-endemic areas.Citation: Hirohisa Mekata, Kentaro Yamada, Kazumi Umeki, Mari Yamamoto, Akihiro Ochi, Kunihiko Umekita, Ikuo Kobayashi, Takuya Hirai, Tamaki Okabayashi, Nine-year seroepidemiological study of severe fever with thrombocytopenia syndrome virus infection in feral horses in Cape Toi, Japan. BMC Veterinary Research. 2024-05-11, 20(1), https://doi.org/10.1186/s12917-024-04042-

Pathological investigation and viral antigen distribution of emerging African swine fever in Vietnam

African swine fever (ASF) is emerging in Vietnam and poses a continuing severe threat to the swine industry. A histopathological study of clinical samples collected during the May to July 2019 outbreak of ASF was performed to determine the characteristic lesions. We analysed samples from eight ASFV-infected farms. Histopathological results revealed the characteristic lesions of the acute to the subacute clinical form of ASF. Immunohistochemical results showed ASFV viral antigen distribution in mononuclear cells/macrophage in various organs, hepatocytes and renal tubular epithelium. Molecular analysis of partial capsid protein 72 gene revealed that ASFV strain from the eight separate outbreaks belonged to genotype II.Citation: Izzati UZ, Inanaga M, Hoa NT, Nueangphuet P, Myint O, Truong QL, Lan NT, Norimine J, Hirai T, Yamaguchi R. Pathological investigation and viral antigen distribution of emerging African swine fever in Vietnam. Transbound Emerg Dis. 2021 Jul;68(4):2039-2050. doi: 10.1111/tbed.13851. Epub 2020 Oct 7. PMID: 32979250; PMCID: PMC8359366