Kato's Method Research Articles

Computer simulation of x-ray section topography of gas pores in a silicon carbide crystal

The results of computer simulation of images of gas pores in a silicon carbide crystal in sectional topograms, that is, during diffraction of a narrow beam of X-rays in the crystal, are presented for the first time. For this purpose, a special module of the universal computer program XRWP was used. This program is developing by the author to calculate the effects of coherent X-ray optics. The calculation method combines two methods, previously known, namely, Fourier transform methods (Kato method), and the method of solving the Takagi-Taupin equations. It is shown that gas pores can produce a wide variety of images, depending on the experimental conditions and the position of the gas pore inside the crystal.

An extension of the Fukaya–Kato method

In a groundbreaking paper, T. Fukaya and K. Kato proved a slight weakening of a conjecture of the author under an assumption that a Kubota–Leopoldt p -adic L -function has no multiple zeros. This article describes a refinement of their method that sheds light on the role of the p -adic L -function.

Распространенность гельминтозов среди сельского населения Хабаровского края

The large medical and socio-economic burden of helminth infections provides the basis for studying the frequency and type of helminth infections among the population of residents of the Russian Far East and is relevant. The purpose of this study was to study the prevalence and type of parasitosis among different age groups of the rural population of the Lazo District. The study was carried out in the design of a retrospective cohort non-randomized continuous study. On the basis of the District Hospital of the Lazo District, 26,483 medical records were processed and analyzed among the adult and child population for the period 2013–2023, with the study of data on the incidence of parasitosis in the rural population based on the results of a microscopic examination of feces for helminth eggs and protozoan cysts ( by Kato method). Statistical analysis was carried out in the STATISTICA 16.0 program, as well as the use of statistical functions of the EXCEL program, using nonparametric data processing methods. After a parasitological survey carried out in 2013–2023, it was revealed that the largest proportion among the infested were children, predominantly in the age group of 4–7 years. There were no significant differences by gender. Based on the set of indicators that determine the structure and dynamics of epidemiological processes in the Lazo District, clonorchiasis (0.07 %, 19 people), ascariasis (0.90 %, 238 people), enterobiasis (1.90 %, 503 people) were diagnostically significant. people), as well as giardiasis (2.00 %, 530 people). There is a need for improved diagnostic tools and effective control options to scale up public health interventions and improve clinical detection and treatment of helminth infections in the Russian Far East.

КЛИНИЧЕСКИЙ СЛУЧАЙ ЛЕЙОМИОМЫ ЖЕЛУДКА И В12 ДЕФИЦИТНОЙ АНЕМИИ НА ФОНЕ ХРОНИЧЕСКОГО ОПИСТОРХОЗА

This case report demonstrates the interrelations between several clinical conditions: gastric leiomyoma, vitamin B12 deficiency anemia, and chronic opistorchiasis. A patient from diphyllobotriosis and opistorchiasis endemic territory presented with the symptoms of vitamin B12 deficiency. An endoscopic investigation found a 2 cm submucous node on the posterior wall of the stomach. Upon histological analysis, the node contained spindle-shaped cells with cigar-shaped nuclei without active mitoses and cell atypia. The immunohistochemical reaction to desmin and α-actin of smooth muscles was positive, while no CD117 and CD34 expression was found. These findings defined the node as a gastric leiomyoma. Multiple stool samples prepared with the Kato technique contained no Diphyllobothrium latum but Opistorchis felineus eggs were found. Kato method cannot rule out diphyllobotriosis completely. Simultaneously, opistorchiasis has no direct pathogenic interrelation with vitamin B12 deficiency anemia. Leiomyomas express the VPAC2 receptors. This makes the gastric glands more sensitive to the vasoactive intestinal polypeptide (VIP) that inhibits gastric secretion. Another possible mechanism that contributes to the vitamin B12 deficiency is autoimmune, where leiomyomas induce the antibodies against the Castle factor. However, the role of a combination of leiomyoma and opistorchiasis is still under discussion. Thus, this case should encourage the future research on the contribution of opistorchiasis to the onset of gastric leiomyoma.

Global existence for the periodic dispersive Hunter–Saxton equation

In this paper, we study an integrable dispersive Hunter–Saxton equation in periodic domain. Firstly, we establish the local well-posedness of the Cauchy problem of the equation in $$H^s ({\mathbb {S}}), s \ge 2,$$ by applying the Kato method. Then, based on a sign-preserve property, we obtain a global existence result for the equation. Moreover, we extend the obtained result to some periodic nonlinear partial differential equations of second order of the general form.

Local well-posedness and blow-up phenomena of the generalized short pulse equation

In this paper, we investigate the Cauchy problem of the generalized short-pulse equation in periodic domain. We first establish the local well-posedness of the equation in Hs(S),s≥2 by taking advantage of the Kato method and present some useful conservation laws. Then, we obtain the boundedness of the solution by virtue of the conservation laws. Finally, we give a precise blow-up criterion for α > 0 (or α < 0) and get several blow-up results provided the initial data satisfies some certain conditions.

Global existence and local well-posedness of the single-cycle pulse equation

In this paper, we mainly study the Cauchy problem of the integrable single-cycle pulse equation in the periodic domain. We first establish the local well-posedness of the equation in Hs(S),s≥2, by using an orthogonal projection of the equation onto mean zero functions and the Kato method. Then, we derive a relationship between the single-cycle pulse equation and the sine-Gordon equation rigorously and reveal some useful conservation laws of the sine-Gordon equation. Next, we deduce a new conservative quantity of the single-cycle pulse equation and get the upper bound of the H2-norm control of the solution. By a precise blow-up criterion, we finally get a global existence result for the equation.

Blow-up phenomena and travelling wave solutions to the periodic integrable dispersive Hunter-Saxton equation

In this paper, we mainly study the Cauchy problem of an integrable dispersive Hunter-Saxton equation in periodic domain. Firstly, we establish local well-posedness of the Cauchy problem of the equation in \begin{document}$H^s (\mathbb{S}), s > \frac{3}{2},$\end{document} by applying the Kato method. Secondly, by using some conservative quantities, we give a precise blow-up criterion and a blow-up result of strong solutions to the equation. Finally, based on a sign-preserve property, we transform the original equation into the sinh-Gordon equation. By using the travelling wave solutions of the sinh-Gordon equation and a period stretch between these two equations, we get the travelling wave solutions of the original equation.

Solutions of fourth-order parabolic equation modeling thin film growth

In this paper we study the well-posedness for a fourth-order parabolic equation modeling epitaxial thin film growth. Using Kato's Method [1–3] we establish existence, uniqueness and regularity of the solution to the model, in suitable spaces, namely C0([0,T];Lp(Ω)) where p=nα2−α with 1<α<2, n∈N and n≥2. We also show the global existence solution to the nonlinear parabolic equations for small initial data. Our main tools are Lp–Lq-estimates, regularization property of the linear part of e−tΔ2 and successive approximations. Furthermore, we illustrate the qualitative behavior of the approximate solution through some numerical simulations. The approximate solutions exhibit some favorable absorption properties of the model, which highlight the stabilizing effect of our specific formulation of the source term associated with the upward hopping of atoms. Consequently, the solutions describe well some experimentally observed phenomena, which characterize the growth of thin film such as grain coarsening, island formation and thickness growth.

High Prevalence of Haplorchiasis in Nan and Lampang Provinces, Thailand, Proven by Adult Worm Recovery from Suspected Opisthorchiasis Cases

Opisthorchiasis, a risk factor for cholangiocarcinoma in humans, is of public health importance in Thailand. The Annual Surveillance Reports from Nan and Lampang Provinces, Thailand, for the year 2011 showed an opisthorchiasis prevalence of over 70% by recovery of eggs in the feces. This study investigated whether most cases are actually due to minute intestinal flukes (MIF) rather than Opisthorchis viverrini, as the eggs of both can hardly be differentiated by morphology. Fifty and 100 cases from residents in Nan and Lampang, respectively, had stools positive for eggs initially assumed to be those of O. viverrini. Each patient was given praziquantel at 40 mg/kg in a single dose. After 2 hr, 30-45 ml of the purgative magnesium sulfate was given, and stools were collected up to 4 times sequentially. The stools were examined for adult worms by simple sedimentation. It was found that 39 of 50 cases (78.0%) from Nan Province had Haplorchis taichui, with intensities ranging from 5 to 1,250 with an average of 62 worms/case. Taenia saginata (7 cases) and Enterobius vermicularis (1 case) were other helminths recovered as the co-infectants. In Lampang Province, H. taichui was recovered from 69 cases (69.0%). The number of flukes recovered ranged from 1 to 4,277, with an average of 326 worms/case. Four cases had Phaneropsolus bonnei, and 10 T. saginata as the co-infectants. Adult specimens of O. viverrini were not recovered from any stool. Clearly, MIF infection, especially haplorchiasis, is more common in northern Thailand. These findings should encourage the Public Health Office to employ more specific tools than Kato's method for surveillance of opisthorchiasis in Thailand.

An Epidemiological Assessment of the Infectious forms of Intestinal Helminths in School Children from Chad

Intestinal helminths constitute the primary cause of illnesses in pre and school age children in the less developed countries. Their importance has been disregarded for a long time because of their insidious and chronic nature. In order to assess the prevalence rate of intestinal helminths in Chadian children, a survey of intestinal worms was carried out from March 2010 to February 2011 intwo ecological zones (Sahelian and Sudanian zones) in the Republic of Chad. 1002 children (541 boys and 461 girls) aged from 6 to 17 years were enrolled in our investigation. The coprological analysis carried out in this study included macroscopic examination, direct microscopic examination and two concentration techniques (the Kato method and the formalin-ether concentration technique). The results showed highly significant differences in the prevalence of intestinal helminths between the two ecological zones, the prevalence being generally higher in the Sudanian zone than in the Sahelian one. Among all the helminths identified in the two zones, Ascaris lumbricoides was the most common, followed by Hymenolepis nana . A regular deworming and improvement of the hygienic conditions in these zones could go a long way to prevent intestinal worm infections. The findings of the present study urgently call for an improvement in environmental hygiene, the sanitary education of the populations and the creation of a national program for the fight against intestinal helminths in Chad.

Diagnostic efficacy of indirect hemagglutination test inrelation to Kato method for diagnosis of &lt;i&gt;Schistosomiasis mansoni&lt;/i&gt;

BACKGROUND: Sensitive and specific diagnostic tools are very central to decide on individual case management and at all stages of control programs in schistosomiasis. This study was undertaken to assess the diagnostic efficacy of a commercial indirect hemagglutination test in detection of schistosomiasis mansoni in relation to the Kato method. METHODS: In a cross sectional study undertaken in May 2004, blood and stool samples were collected from 134 children in Bochesa Elementary School around Ziway town. The stool specimens were processed using Kato method and examined microscopically. Eggs per gram of stool were computed as geometric mean. Sera were separated and transported to laboratory. Indirect hemagglutination test was performed following procedures given by the manufacturers. The diagnostic performance of indirect hemagglutination was evaluated using Kato as the gold standard. RESULTS: The overall prevalence of intestinal schistosomiasis as detected by indirect hemagglutination test and Kato method was 74.6% and % 76.1%, respectively (p = 0.284). The respective prevalence of infection as detected by indirect hemagglutination tests and Kato method among male students was 82.6% and 85.0 % where as the corresponding value for females was 60.4% for both indirect hemagglutination test and Kato method. The sensitivity and specificity of the indirect hemagglutination test were 83% and 53%, the positive predictive value being 85%. However, there was discrepancy between indirect hemagglutination test and Kato method in determining the intensity of infection. Only 5% of the examined individuals had light infection with a cut off titer of 81: 256 as detected by IHA test while 95% of the cases had heavy infection with a cut off titer of ; 1: 512. On the other hand, the Kato method revealed that 18.5% of the children was heavily infected (;400 epg) while 81.5 % of them had light to moderate infection (8399 epg). CONCLUSIONS: The present findings indicate that indirect hemagglutination test can be used as an adjunct to the Kato method for field use in the diagnosis of intestinal chistosomiasis. Nevertheless, the fact that the test is expensive and also not a rapid test may limit its use in the field for epidemiological application.

Well-posedness of the fourth-order perturbed Schrödinger type equation in non-isotropic Sobolev spaces

In this paper we study the Cauchy problem of the non-isotropically perturbed fourth-order nonlinear Schrödinger type equation: i u t + △ u + a ∑ i = 1 d u x i x i x i x i + g ( x , | u | ) u = 0 ( ( x 1 , x 2 , … , x n ) ∈ R n , t ⩾ 0 ), where a is a real constant, 1 ⩽ d < n is an integer, g ( x , | u | ) u is a nonlinear function which behaves like | u | α u for some constant α > 0 . By using Kato method, we prove that this perturbed fourth-order Schrödinger type equation is locally well-posed with initial data belonging to the non-isotropic Sobolev spaces H x → s 1 H y → s 2 provided that s 1 , s 2 satisfy the conditions: s 1 ⩾ 0 , s 2 ⩾ 0 for 0 < α < 8 2 n − d or 2 s 1 + 4 s 2 > 2 n − d − 8 α for α ⩾ 8 2 n − d with some additional conditions. Furthermore, by using non-isotropic Sobolev inequality and energy method, we obtain some global well-posedness results for initial data belonging to non-isotropic Sobolev spaces H x → 2 H y → 1 .

Cauchy problem for higher-order Schrödinger equations in anisotropic Sobolev space

We study the solvability in anisotropic Sobolev spaces for the Cauchy problem of the nonisotropically perturbed sixth-order nonlinear Schrödinger equation: , where a, b are real constants, 1 ≤ d < n and x = (x 1, x 2, …, x n ) ∈ R n , t ∈ R and f(u) is a given complex function. By using Kato's method, we establish local well-posedness for the equation. We also obtain its global solvability by the anisotropic Sobolev embedding relations and the energy method.

A note on modification of pancreatic juice and bile collection method in sheep

The aim of the study was to modify and evaluate the method of management of pancreatic juice and bile secretions in sheep in chronic experiment. Experiment was performed on 12 adult male Corriedale sheep of 54 ± 2.4 kg body weight, fi tted with two biomedical silicone catheters in the common bile duct according to the method described by Kato and Young (Kato et al., 1999) and our modifi cation duodenal cannula. Duodenal cannula was equipped with silicone valve in the basement part to prevent secretions backfl ow. Except the collection time, animals were freely moving in the individual pens and all secretions were returned to duodenum by means of constructed device. During all experimental treatments secretion volume of pancreatic juice was from 11.7 to 34.8 ml·h -1 . Modifi cation of Kato and Young method allows extending the period of animals use even up to more than 6 months. Moreover, it positively impacts animals welfare by reducing time spending in the metabolic cages, and saves labour expenses.

Field-based evaluation of a reagent strip test for diagnosis of Schistosomiasis mansoni by detecting circulating cathodic antigen (CCA) in urine in low endemic area in Ethiopia

The sensitivity, specificity, positive and negative predictive values of a reagent strip test for the diagnosis of schistosomiasis mansoni by detecting circulating cathodic antigen (CCA) in urine were evaluated using 184 stool and urine samples collected from schoolchildren living in relatively low endemic area of schistosomiasis mansoni in Ethiopia. A combined result of stool samples processed by Kato and formol-ether concentration methods was used as gold standard. The results showed that detection of CCA in urine using reagent strip test was slightly higher than the combined results of the stool techniques (65.2 % vs 42.4 %, p > 0.05) in suggesting the prevalence of the disease. The sensitivity, specificity, positive and negative predictive values of the reagent strip test were 76.9 %, 43.4 %, 50 % and 71.9 %, respectively. The result of egg counts using Kato method suggested that detection of urine CCA could be used to indicate the intensity of infection. Nevertheless, like that of stool examination, the reagent strip test was found to be less sensitive in case of light to moderate infections. About 23.1 % of the study children who were excreting the eggs of the parasite were found negative by the reagent strip test. The relative insensitivity of a reagent strip test in low intensity of infection necessitates for the development of more sensitive assay that can truly discriminate schistosome-infected from non-infected individuals.

IFN-gamma is associated with risk of Schistosoma japonicum infection in China.

Before the start of the schistosomiasis transmission season, 129 villagers resident on a Schistosoma japonicum-endemic island in Poyang Lake, Jiangxi Province, 64 of whom were stool-positive for S. japonicum eggs by the Kato method and 65 negative, were treated with praziquantel. Forty-five days later the 93 subjects who presented for follow-up were all stool-negative. Blood samples were collected from all 93 individuals. S. japonicum soluble worm antigen (SWAP) and soluble egg antigen (SEA) stimulated IL-4, IL-5 and IFN-gamma production in whole-blood cultures were measured by ELISA. All the subjects were interviewed nine times during the subsequent transmission season to estimate the intensity of their contact with potentially infective snail habitats, and the subjects were all re-screened for S. japonicum by the Kato method at the end of the transmission season. Fourteen subjects were found to be infected at that time. There was some indication that the risk of infection might be associated with gender (with females being at higher risk) and with the intensity of water contact, and there was evidence that levels of SEA-induced IFN-gamma production were associated with reduced risk of infection.

IFN‐γ is associated with risk of Schistosoma japonicum infection in China

SUMMARYBefore the start of the schistosomiasis transmission season, 129 villagers resident on a Schistosoma japonicum‐endemic island in Poyang Lake, Jiangxi Province, 64 of whom were stool‐positive for S. japonicum eggs by the Kato method and 65 negative, were treated with praziquantel. Forty‐five days later the 93 subjects who presented for follow‐up were all stool‐negative. Blood samples were collected from all 93 individuals. S. japonicum soluble worm antigen (SWAP) and soluble egg antigen (SEA) stimulated IL‐4, IL‐5 and IFN‐γ production in whole‐blood cultures were measured by ELISA. All the subjects were interviewed nine times during the subsequent transmission season to estimate the intensity of their contact with potentially infective snail habitats, and the subjects were all re‐screened for S. japonicum by the Kato method at the end of the transmission season. Fourteen subjects were found to be infected at that time. There was some indication that the risk of infection might be associated with gender (with females being at higher risk) and with the intensity of water contact, and there was evidence that levels of SEA‐induced IFN‐γ production were associated with reduced risk of infection.

The epidemiology of schistosomiasis in Egypt: patterns of Schistosoma mansoni infection and morbidity in Kafer El-Sheikh.

This is a descriptive report of the Epidemiology 1, 2, 3 project in Egypt that made use of large probability sampling methods. These results focus on Schistosoma mansoni infection in the northern Nile Delta governorate of Kafr El Sheikh. A probability sample of 18,777 persons, representing the rural population of the entire governorate, was drawn. The sample was designed not to exclude villages based on location or presence of health care facilities and to include representation of the smaller ezbas or hamlets. The objective was to obtain detailed estimates on age- and sex-specific patterns of S. mansoni infection, and to provide a baseline for prospective studies. Stool specimens were examined by the Kato method. The estimated mean +/- SE prevalence of S. mansoni infection in the rural population was 39.3 +/- 3.3% in 44 villages and ezbas after weighing for the effects of the sample design. The estimated mean +/- SE geometric mean egg count per gram of stool (GMEC) was 72.9 +/- 7.3. Prevalence and GMEC varied considerably by village and ezba, with ezbas having a significantly higher prevalence. Villages and ezba-specific prevalence was strongly associated with GMEC (r2 = 0.61, P < 0.001). The prevalence of S. mansoni infection increased by age to 55.4 +/- 3.2% at age 16 without a significant change in the adult ages. There were no gender differences until age 6, after which males were consistently higher until middle age, when the differences converged. The age- and sex-specific pattern of GMEC varied widely; however, when the GMEC data were collapsed into 5-year age groups, the GMEC peaked at 81.5 +/- 12.1 eggs/g in the 10-14-year-old age group. These estimates provide the basis for evaluating control measures for reducing prevalence, intensity of infection, and transmission.

Two methods for solving the Dirac equation without variational collapse

Two special variational techniques, the Lehmann-Maehly (LM) method and the Kato method, recently proposed for solving the one-electron Dirac equation without variational collapse are investigated here in detail. Both methods represent significant progress compared to the traditional variational techniques because each of them provides rigorous upper and lower bounds to relativistic binding energies. A careful theoretical examination, however, reveals that only the LM method can be regarded as a radical solution of all the problems related to variational collapse. A numerical application to the Dirac equation for the hydrogen atom in a uniform magnetic field confirms this conclusion and shows as well that the LM method is also capable of yielding extremely accurate results and that the Kato method, in spite of a few limitations, represents in any case a useful approach.