In this task, you're given a paragraph from the research paper and your task is to generate a suitable title for the research paper based on the given paper. Under 100 words is a good title length.

[EX Q]: Coronavirus reverse genetic systems have become valuable tools for studying the molecular biology of coronavirus infections. They have been applied to the generation of recombinant coronaviruses, selectable replicon RNAs, and coronavirus-based vectors for heterologous gene expression. Here we provide a collection of protocols for the generation, cloning, and modification of full-length coronavirus cDNA using vaccinia virus as a cloning vector. Based on cloned coronaviral cDNA, we describe the generation of recombinant coronaviruses and stable cell lines containing coronaviral replicon RNAs. Initially, the vaccinia virus-based reverse genetic system was established for the generation of recombinant human coronavirus 229E. However, it is also applicable to the generation of other coronaviruses, such as the avian infectious bronchitis virus, mouse hepatitis virus, and SARS coronavirus.
[EX A]: Generation of Recombinant Coronaviruses Using Vaccinia Virus as the Cloning Vector and Stable Cell Lines Containing Coronaviral Replicon RNAs

[EX Q]: One word can be used to best describe the theme of each day that has transpired since the onset of the COVID-19 pandemic: uncertainty. Urologic surgical residents around the nation are faced with the unknown when they walk through the doors of the hospital each day. While experience has taught us navigational strategies to handle these circumstances, the COVID-19 pandemic has undoubtedly brought new meaning to this concept. Priorities have quickly transitioned from closely following our previously developed academic curriculum and enhancing our surgical skills, to limiting physician-patient encounters and ensuring the safety and health of our team. Normalcy within our professional and personal lives is completely lost. Yet, as health care providers, we must and will forge on. We review the techniques and guidelines that our institution has implemented in order to allow us to do just that. We believe that our leadership, both at an enterprise and program level, has taken the necessary and early measures to prepare our residency cohort for the uncertain future and challenges posed by COVID-19. This plan emphasizes social and professional distancing, allows residents and faculty to stay current on academic topics, and provides reasonable opportunities for personal wellness, all while emphasizing safety and rationalization. Most importantly, however, we have continued to provide our patients with exceptional urologic care at 2 adult hospitals and 1 children's hospital in the Greater Akron, Ohio area. While we understand each residency program has a unique curriculum with a different number of residents that cover a range of different hospitals, we hope to provide insight into our personal experience. We believe that this method of organization allows a residency program to continue to grow professionally, socially, academically, and personally during the uncertainty that is COVID-19. This framework could serve as an immediate action plan for future pandemics and natural disasters, especially for residency programs that cover multiple hospitals and health care settings.
[EX A]: Editorial Cleveland Clinic Akron General Urology Residency Program's COVID-19 Experience

[EX Q]: It is well known that piglets congenitally infected with porcine reproductive and respiratory syndrome virus (PRRSV) can be viremic at birth, and that preweaning mortality due to secondary infections often increases during acute outbreaks of PRRS. Therefore, an immunosuppressive effect of in utero infection has been suggested. The aim of the present study was to characterise the changes of leukocyte populations in piglets surviving in utero infection with PRRSV. A total of 27 liveborn uninfected control piglets and 22 piglets infected transplacentally with a Danish strain of PRRSV were included. At 2 and 4 weeks of age, 21 of 22 (96%) and 7 of 14 (50%) examined infected piglets were still viremic, whereas PRRSV could not be detected in the six infected piglets examined at 6 weeks of age. Flow cytometry analysis was used to determine the phenotypic composition of leukocytes in peripheral blood and bronchoalveolar lavage fluid (BALF) of 2-, 4-and 6-week-old infected piglets and age-matched uninfected controls. The key observation in the present study is that high levels of CD8 þ cells constitute a dominant feature in peripheral blood and BALF of piglets surviving in utero infection with PRRSV. In BALF, the average high level of CD8 þ cells in 2-week-old infected piglets (33:4 AE 12:6%) was followed by a decline to 7:3 AE 3:0 and 11:1 AE 3:0% at 4 and 6 weeks of age. BALF of control piglets contained 1:6 AE 0:9, 2:3 AE 1:8 and 1:9 AE 0:5% CD8 þ cells, only. In peripheral blood, however, the average number of CD8 þ cells remained at high levels in the infected piglets throughout the post-natal experimental period (2:8 AE 1:9, 2:9 AE 1:8 and 3:2 AE 1:7 Â 10 6 CD8 þ cells/ml at 2, 4 and 6 weeks, respectively). In the controls, the average levels of CD8 þ cells were 0:9 AE 0:2, 1:9 AE 1:7 and 1:6 AE 0:5 Â 10 6 /ml, respectively. Furthermore, the numbers of CD2 þ , CD4 þ CD8 þ and SLA-classII þ cells, respectively, in peripheral blood, together with the levels of CD2 þ and CD3 þ cells in BALF were increased in the infected piglets infected in utero compared to the uninfected controls. Veterinary Immunology and Immunopathology 93 (2003) 135-151 Abbreviations: SLA, swine leukocyte antigen; FSC, forward light scattering; SSC, side light scattering; BALF, bronchoalveolar lavage fluid; PPAM, porcine pulmonary alveolar macrophages; WBC, white blood cells; CD, cluster of differentiation The kinetic analyses carried out in the present study reflect that in utero infection with PRRSV modulates immune cell populations in peripheral blood and BALF of surviving piglets. The observed changes are characterised by high levels of CD8 þ cells supporting an important role of these cells in PRRSV infection. The present results, however, do not support the existence of post-natal immunosuppression following in utero infection with PRRSV. #
[EX A]:
In utero infection with porcine reproductive and respiratory syndrome virus modulates leukocyte subpopulations in peripheral blood and bronchoalveolar fluid of surviving piglets