Molecular studies on infections with two nidoviruses: Bovine Coronavirus and Equine Arteritis Virus

Infections with nidoviruses can cause various problems in animals and human beings. Bovine coronavirus (BCoV) has been considered as an important pathogen, causing severe diarrhea of newborn calves, winter dysentery of adult cattle, and respiratory disease in calves. Since this virus is repeatedly reported to cause severe disease in the Swedish cattle population, it is important to develop a highly sensitive diagnostic method for the detection of BCoV and to study the genetic characteristics of virus involved in the outbreaks. A nested RT-PCR method targeting the HE gene was developed, which can be successfully applied for the diagnosis of BCoV infection. A conventional PCR was used to amplify the S gene of BCoV. Sequence analysis of the S gene showed a genetic diversity among Swedish and Danish virus isolates. S gene sequencing did not reveal differences between viruses from nasal and fecal swabs originating from the same animal, suggesting that the same virus can cause respiratory and enteric disease. Horses are infected with equine arteritis virus (EAV) primarily through the respiratory and venereal routes. The outcome can vary greatly from subclinical infection to systemic disease characterised by fever, nasal discharge, lacrimation, arteritis, abortion, fetal death, and persistent infection in stallions. The LP3A1+ strain, a virus stock that was obtained by one additional cell culture passage of the LP3A virus, a large plaque variant of EAV Bucyrus strain, in equine embryonic cells was shown to be more virulent than the LP3A virus. An experimental infection has been done with a group of 14 horses to further characterise the in vivo biology of this LP3A1+ virus. Analysis of open reading frames (ORFs) encoding EAV glycoproteins (GP) has shown the occurrence of mutations in the course of the experimental infection. While ORFs 2b and 3 had stabilizing mutations, ORFs 4 and 5 were subject to positive selection. Mutations in ORF5 mainly clustered in variable region 1, resulting in new genetic variants with changed neutralization domain in the GP5 (previously termed GL). The new virus variants, however could not be entirely related to induction of recurrent viraemia in the infected horses, which is presumed to have been caused by other factors. It would be of interest to investigate the occurrence of other forms of persistent infection, rather than carrier stallions, upon infection with EAV.Samples originating from a group of 14 horses experimentally infected with a variant of equine arteritis virus (EAV) Bucyrus strain, termed large plaque variant (LP3A1+) were analysed. These included 182 nasal swabs collected from day 1 to day 14 post-infection (p.i), and 21 virus isolates obtained from white blood cells of horses that showed a secondary viraemia between day 30 and day 72 p.i. In order to understand the reason for this virus behaviour, genetic stability of the virus was studied by comparison of partial open reading frame 5 (ORF5), specifying glycoprotein 5 (GP5). Viruses with amino acid mutations in GP5 were used for further amplification and sequencing of a fragment encompassing ORFs 2b, 3, and 4. The sequences of the virus obtained from nasal swabs shared complete homology with the inoculated virus showing that the ORF5 gene of LP3A1+ was genetically stable during the first two weeks p.i. However, a number of mutations were found in the ORF5 of virus isolates obtained from day 30 p.i. when compared to the original inoculated virus. These mutations mainly clustered in antigenic neutralization site C within variable region 1 of the GP5 ectodomain. ORFs 2b and 3 had mostly silent substitutions and were more stable, whereas ORF4 showed non-conservative substitutions. Our results show that ORFs 4 and 5 of the inoculated LP3A1+ virus were subject to positive selection, most likely driven by immunological pressure, during the course of infection. However, genetic variation did not appear to be the underlying reason for the onset of a second wave of viraemia. It is plausible that the virus had been “trapped” at immune privilege sites, following initial infection, and was triggered to replicate by an unknown stimulus, therefore causing reappearance of viraemia

Periodic solutions for nonlinear nth order differential equations with delays

AbstractBy applying the continuation theorem of coincidence degree theory, we establish the existence of 2π-periodic solutions for a class of nonlinear nth order differential equations with delays

Existence and uniqueness of periodic solutions for a kind of Liénard equation with a deviating argument

AbstractIn this work, we use the coincidence degree theory to establish new results on the existence and uniqueness of T-periodic solutions for a kind of Liénard equation with a deviating argument of the form x″(t)+f(x(t))x′(t)+g(t,x(t−τ(t)))=p(t)

Fighting against fast speckle decorrelation for light focusing inside live tissue by photon frequency shifting

Light focusing inside live tissue by digital optical phase conjugation (DOPC) has drawn increasing interest due to its potential biomedical applications in optogenetics, microsurgery, phototherapy, and deep-tissue imaging. However, fast physiological motions in a live animal, including blood flow and respiratory motions, produce undesired photon perturbation and thus inevitably deteriorate the performance of light focusing. Here, we develop a photon-frequency-shifting DOPC method to fight against fast physiological motions by switching the states of a guide star at a distinctive frequency. Therefore, the photons tagged by the guide star are well detected at the specific frequency, separating them from the photons perturbed by fast motions. Light focusing was demonstrated in both phantoms in vitro and mice in vivo with substantially improved focusing contrast. This work puts a new perspective on light focusing inside live tissue and promises wide biomedical applications

Graphics processing unit accelerating compressed sensing photoacoustic computed tomography with total variation

Photoacoustic computed tomography with compressed sensing (CS-PACT) is a commonly used imaging strategy for sparse-sampling PACT. However, it is very time-consuming because of the iterative process involved in the image reconstruction. In this paper, we present a graphics processing unit (GPU)-based parallel computation framework for total-variation-based CS-PACT and adapted into a custom-made PACT system. Specifically, five compute-intensive operators are extracted from the iteration algorithm and are redesigned for parallel performance on a GPU. We achieved an image reconstruction speed 24–31 times faster than the CPU performance. We performed in vivo experiments on human hands to verify the feasibility of our developed method

El rol de la motivación en los efectos de las relaciones profesor-estudiante en el rendimiento de la lengua extranjera

The present study investigated whether students’ motivational beliefs act as a mediator in the association between teacher-student relationships (TSRs) and foreign language performance with a multiple mediation model. Furthermore, this research examined whether mediating roles of intrinsic and extrinsic motivation differ. A total of 1171 eighth graders (583 male, 588 female) were chosen with purposive sampling in China. Studentreported measures of TSRs, intrinsic and extrinsic motivation, and English as a Foreign Language (EFL) test based on national curriculum were administrated in October 2017. Results showed that the positive link between TSRs and foreign language performance is partially mediated by intrinsic and extrinsic motivation, and the mediation effect of intrinsic motivation is significantly greater than that of extrinsic motivation, controlling for gender and socio-economic status. The results indicated that supportive TSRs can help learners to improve their foreign language proficiency by promoting their motivation, especially intrinsic motivation. The present results may have substantive theoretical and practical implications for teacher education and foreign language learning.El presente estudio investigó si las creencias motivacionales de los estudiantes actúan como mediadores en la asociación entre las relaciones profesor-alumno (TSR) y el rendimiento de un idioma extranjero con un modelo de mediación múltiple. Además, esta investigación examinó si los roles mediadores de la motivación intrínseca y extrínseca difieren. Se eligieron 1171 alumnos de octavo grado (583 hombres, 588 mujeres) con muestreo intencional en China. En octubre de 2017, se aplicaron a los estudiantes las pruebas de TSR, la motivación intrínseca y extrínseca y la prueba de inglés como idioma extranjero (EFL) basadas en el plan de estudios nacional. Los resultados mostraron que el vínculo positivo entre TSR y el desempeño de un idioma extranjero está parcialmente mediado por la motivación intrínseca y extrínseca, y el efecto de mediación de la motivación intrínseca es significativamente mayor que el de la motivación extrínseca, controlando el género y el estatus socioeconómico. Los resultados indicaron que los TSR de apoyo pueden ayudar a los alumnos a mejorar su dominio del idioma extranjero ya que promueven su motivación, especialmente la motivación intrínseca. Los resultados actuales pueden tener importantes implicaciones teóricas y prácticas para la formación del profesorado y el aprendizaje de lenguas extranjeras.&nbsp

El rol de la motivación en los efectos de las relaciones profesor-estudiante en el rendimiento de la lengua extranjera

The present study investigated whether students’ motivational beliefs act as a mediator in the association between teacher-student relationships (TSRs) and foreign language performance with a multiple mediation model. Furthermore, this research examined whether mediating roles of intrinsic and extrinsic motivation differ. A total of 1171 eighth graders (583 male, 588 female) were chosen with purposive sampling in China. Studentreported measures of TSRs, intrinsic and extrinsic motivation, and English as a Foreign Language (EFL) test based on national curriculum were administrated in October 2017. Results showed that the positive link between TSRs and foreign language performance is partially mediated by intrinsic and extrinsic motivation, and the mediation effect of intrinsic motivation is significantly greater than that of extrinsic motivation, controlling for gender and socio-economic status. The results indicated that supportive TSRs can help learners to improve their foreign language proficiency by promoting their motivation, especially intrinsic motivation. The present results may have substantive theoretical and practical implications for teacher education and foreign language learning.El presente estudio investigó si las creencias motivacionales de los estudiantes actúan como mediadores en la asociación entre las relaciones profesor-alumno (TSR) y el rendimiento de un idioma extranjero con un modelo de mediación múltiple. Además, esta investigación examinó si los roles mediadores de la motivación intrínseca y extrínseca difieren. Se eligieron 1171 alumnos de octavo grado (583 hombres, 588 mujeres) con muestreo intencional en China. En octubre de 2017, se aplicaron a los estudiantes las pruebas de TSR, la motivación intrínseca y extrínseca y la prueba de inglés como idioma extranjero (EFL) basadas en el plan de estudios nacional. Los resultados mostraron que el vínculo positivo entre TSR y el desempeño de un idioma extranjero está parcialmente mediado por la motivación intrínseca y extrínseca, y el efecto de mediación de la motivación intrínseca es significativamente mayor que el de la motivación extrínseca, controlando el género y el estatus socioeco-nómico. Los resultados indicaron que los TSR de apoyo pueden ayudar a los alumnos a mejorar su dominio del idioma extranjero ya que promueven su motivación, especialmente la motivación intrínseca. Los resultados actuales pueden tener importantes implicaciones teóricas y prácticas para la formación del profesorado y el aprendizaje de lenguas extranjera

A Rare Root Canal Configuration of a Maxillary Second Molar with Fused C-shaped Buccal Root and Five Canals: A Case Report and Review of literature

Having a thorough knowledge of root canal configuration is essential for a successful endodontic treatment. Clinicians should always pay attention to the unusual canal configuration so as to avoid missing extra canals. This paper describes a non-surgical retreatment of a maxillary second molar with two missing root canals; diagnosed by cone-beam computed tomographic (CBCT) imaging. The tooth had three roots and five canals: a C-shaped buccal root fused by mesiobuccal (MB) and distobuccal (DB) roots with three canals (CBCT scanning showed that the second MB canal was closer to the palatal than the buccal side), a mesiopalatal root with one canal, and a distopalatal root with one canal. The purpose of this case report is to remind clinicians of the importance of anatomical variations, and thus, detection of extra canals.Keywords: Maxillary Second Molar; C-shaped Canal; Cone-Beam Computed Tomograph