The multiple personalities of Watson and Crick strands

<p>Abstract</p> <p>Background</p> <p>In genetics it is customary to refer to double-stranded DNA as containing a "Watson strand" and a "Crick strand." However, there seems to be no consensus in the literature on the exact meaning of these two terms, and the many usages contradict one another as well as the original definition. Here, we review the history of the terminology and suggest retaining a single sense that is currently the most useful and consistent.</p> <p>Proposal</p> <p>The <it>Saccharomyces </it>Genome Database defines the Watson strand as the strand which has its 5'-end at the short-arm telomere and the Crick strand as its complement. The Watson strand is always used as the reference strand in their database. Using this as the basis of our standard, we recommend that Watson and Crick strand terminology only be used in the context of genomics. When possible, the centromere or other genomic feature should be used as a reference point, dividing the chromosome into two arms of unequal lengths. Under our proposal, the Watson strand is standardized as the strand whose 5'-end is on the short arm of the chromosome, and the Crick strand as the one whose 5'-end is on the long arm. Furthermore, the Watson strand should be retained as the reference (plus) strand in a genomic database. This usage not only makes the determination of Watson and Crick unambiguous, but also allows unambiguous selection of reference stands for genomics.</p> <p>Reviewers</p> <p>This article was reviewed by John M. Logsdon, Igor B. Rogozin (nominated by Andrey Rzhetsky), and William Martin.</p

LATE-TIME PHOTOMETRY OF TYPE IA SUPERNOVA SN 2012cg REVEALS THE RADIOACTIVE DECAY OF Co-57

Seitenzahl et al. have predicted that roughly three years after its explosion, the light we receive from a Type Ia supernova (SN Ia) will come mostly from reprocessing of electrons and X-rays emitted by the radioactive decay chain 57Co → 57Fe, instead of positrons from the decay chain 56Co → 56Fe that dominates the SN light at earlier times. Using the Hubble Space Telescope, we followed the light curve of the SN Ia SN 2012cg out to 1055 days after maximum light. Our measurements are consistent with the light curves predicted by the contribution of energy from the reprocessing of electrons and X-rays emitted by the decay of 57Co, offering evidence that 57Co is produced in SN Ia explosions. However, the data are also consistent with a light echo ∼14 mag fainter than SN 2012cg at peak. Assuming no light-echo contamination, the mass ratio of 57Ni and 56Ni produced by the explosion, a strong constraint on any SN Ia explosion models, is 0.043 0.011 0.012 - + , roughly twice Solar. In the context of current explosion models, this value favors a progenitor white dwarf with a mass near the Chandrasekhar limit

Sublimation and deposition in gaseous mixtures

The sublimation and deposition behaviors of the Helium-Argon mixture is analyzed numerically in the temperature range where Helium is only in gaseous state while Argon can sublimate and deposit on its own solid phase. The McCormack model is implemented to model the Boltzmann collision term. Three kinds of potential are used for simulation of the intermolecular collisions: Hard Sphere, Lennard-Jones potential, and ab initio. The matrices of the kinetic coefficients have been obtained for different values of the rarefaction parameters and molar fraction of non-sublimating gas. The influence of the intermolecular potential on the kinetic coefficients as well as on the gas macroscopic profiles has been analyzed. © 2020 Elsevier LtdThe work of A. Polikarpov was financially supported by the Ministry of Science and Higher Education of the Russian Federation, the research project no. FEUZ-2020-0057. I. Graur would like to acknowledge the financial support provided by the European Union network program H2020, MIGRATE project under Grant Agreement No. 643095. F. Sharipov acknowledges the Brazilian Agency CNPq for the support of his research, grant 304831/2018-2

Modern surgical tactic in Mirizzi syndrome

Catedra 2 Chirurgie, USMF „Nicolae Testemiţanu”, Chişinău, Republica Moldova, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Scopul studiului a fost optimizarea tratamentului chirurgical al fistulelor colecisto-coledociene (sindromului Mirizzi). Material şi metode: Pe parcursul ultimilor 20 de ani în Clinica 2 Chirurgie au fost trataţi 64 (0,24%) pacienţi cu sindromul Mirizzi dintr-un lot total de 26.530 cazuri de colecistită calculoasă. Rezultate: Sonografic am apreciat prezenţa stazei biliare, a unui colecist deformat cu lipsa unui coraport obişnuit cu CBP, prezenţa colecistului „călăreţ” pe CBP. Diagnosticul topic a fost stabilit prin ERCP în 46 (71,8%) cazuri. Din ele în 10 (15,6%) observaţii am recurs adăugător la CRMN, care a soluţionat în 100% situaţia diagnostică dată. În celelalte 8 (12,5%) cazuri diagnosticul s-a stabilit intraoperator. Tratamentul chirurgical a inclus obligatoriu: înlăturarea fistulei colecistocoledociene şi coledocolitotomie. Aşa în 27 (42,1%) cazuri, unde defectul parietal coledocian a fost sub 1/3 din diametrul lui, am finisat intervenţia cu un drenaj tip Kehr al CBP. Pentru 8 (12,5%) observaţii, la care defectul coledocian a fost de 2/3 din diametru, am rezolvat situaţia prin plastia CBP cu lambou vascularizat din vezica biliară şi un eventual drenaj al CBP după Vişnevskii. La 19 (29,6%) pacienţi vezica biliară şi CBP formau o cavitate comună cu calculi biliari în lumen. La toţi aceşti pacienţi am efectuat colecistectomie cu coledocolitotomie şi coledocojejunoanastomoză pe ansa jejunală izolată a la Roux. Cazuri letale portoperatorii nu au fost. Concluzii: Sindromul Mirizzi este una din cele mai nefavorabile evoluţii a colecistitei calculoase, ce necesită un program de diagnostic complex şi o atitudine chirurgicală strict individuală.Aim of the study was to optimize surgical treatment of Mirizzi syndrome. Material and methods: In the last 20 years in surgical departament no.2 were treated 64 (0.24%) patients with Mirizzi syndrome from total of 26.530 cases of cholelithiasis. Results: We appreciated sonographic bile stasis, presence of a deformed gallbladder, lack of co-report CBP accustomed to the presence of gallbladder „rider” on CBP. The topical diagnosis was established by CPGRE in 46 (71.8%) cases, in 10 (15.6%) cases we used additionally to CNMR, which settled 100% once the diagnostic situation, in the other eight (12.5%) cases the diagnosis has been established intraoperatively. Surgical treatment included mandatory removal of colecistocoledocian fistula and coledocolitotomie. In 27 (42.1%) cases where the parietal duct defect was under 1/3 of circumference, the intervention was finished with a Kehr drainage of CBP. In eight (12.5%) cases the defect was 2/3 of the duct diameter, we have solved the situation by CBP plasty with vascularized flap of gallbladder and CBP drainage by Vishnevski. In 19 (29.6%) patients gallbladder and CBP were a gallstone in the common cavity lumen. In all patients we performed cholecystectomy with coledocolitotomy and coledocojejunostomy on isolated Roux jejunal loop. Postoperative lethality has not been determined. Conclusions: Mirizzi syndrome is one of the worst developments of cholelithiasis, which requires a complex diagnostic program and a strictly individual surgical tactics

Perioperative management of patients undergoing pancreaticoduodenectomies (PD). Surgical clinic no. III Cluj expertise

Clinica Chirurgie III, Institutul Regional de Gastroenterologie si Hepatologie, UMF “Iuliu Hatieganu” Cluj-Napoca, România, Al XIII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” și al III-lea Congres al Societății de Endoscopie, Chirurgie miniminvazivă și Ultrasonografie ”V.M.Guțu” din Republica MoldovaIntroducere: În 2009, în Clinica Chirurgie III Cluj-Napoca a fost introdus un protocol care cuprinde aspecte legate de pregătirea preoperatorie a pacienților pentru DPC, de tactica și tehnica intraoperatorie, și tratament postoperator. Material si metode: Studiul înrolează 444 pacienti cu DPC operați în clinica între 2009-2018, împărțiți în două loturi: 2009-2015 și 2016-2018. Au fost urmăriți factorii incriminați în apariția principalelor complicații postoperatorii, rezultatele fiind comparate cu cele obținute înainte de 2009. Informaţiile s-au colectat utilizând Excel 2009, analiza statistică efectuandu-se cu software-ul R v3.2.4. Rezultate: Nu am obtinut reducerea semnificativă a morbidității (53% înainte de 2009, 45,6% între 2009-2015 și 42% între 2016- 2018), însă a scăzut rata de apariție a fistulei pancreatice (de la 10% la 9,06%, respectiv 7,5%) și a stazei gastrice (de la 43% la 20,47%, respectiv 12,8%). Hemoragia bontului pancreatic a apărut mai frecvent (de la 2%, la 6,71%, respectiv 7,2%). Mortalitatea s-a redus semnificativ (de la 11,9%, la 6,04%, respectiv 3,99%), datorită scăderii fistulelor pancreatice grad C. Concluzie: Implementarea protocolului de pregătire a DPC și-a dovedit utilitatea, iar preocuparea de îmbunătațire a acestuia, prin adaptarea la literatură și la propria experiență rămâne o prioritate.Introduction: In 2009, a protocol was introduced at the Surgical Clinic III Cluj-Napoca, which included aspects related to preoperative preparation of patients for PD, intraoperative tactics and technique, and postoperative treatment. Material and Method: The study includes 444 patients with PD operated in the clinic between 2009-2018, divided into two batches: 2009-2015 and 2016-2018. We followed the factors involved in the occurrence of the main postoperative complications and the results were compared with those we obtained before 2009. The information was collected using Excel 2009, the statistical analysis being performed with the software R v3.2.4. Results: We have not achieved a significant decrease in morbidity (53% before 2009, 45.6% between 2009-2015 and 42% between 2016-2018), but decreased the rate of pancreatic fistula (from 10% to 9, 06% and 7.5% respectively) and gastric stasis (from 43% to 20.47% and 12.8% respectively). Pancreas bleeding occurred more frequently (from 2% to 6.71% and 7.2%, respectively). Mortality was significantly reduced (from 11.9% to 6.04% and 3.99%, respectively) due to the reduce rate of grade C pancreatic fistulae. Conclusion: Implementation of the protocol has proven useful and the concern for improvement by adapting it to literature and our experience remains a priority