700 research outputs found
Genes in the postgenomic era
We outline three very different concepts of the gene - 'instrumental', 'nominal', and 'postgenomic'. The instrumental gene has a critical role in the construction and interpretation of experiments in which the relationship between genotype and phenotype is explored via hybridization between organisms or directly between nucleic acid molecules. It also plays an important theoretical role in the foundations of disciplines such as quantitative genetics and population genetics. The nominal gene is a critical practical tool, allowing stable communication between bioscientists in a wide range of fields grounded in well-defined sequences of nucleotides, but this concept does not embody major theoretical insights into genome structure or function. The post-genomic gene embodies the continuing project of understanding how genome structure supports genome function, but with a deflationary picture of the gene as a structural unit. This final concept of the gene poses a significant challenge to conventional assumptions about the relationship between genome structure and function, and between genotype and phenotype
Franck-Condon Effect in Central Spin System
We study the quantum transitions of a central spin surrounded by a
collective-spin environment. It is found that the influence of the
environmental spins on the absorption spectrum of the central spin can be
explained with the analog of the Franck-Condon (FC) effect in conventional
electron-phonon interaction system. Here, the collective spins of the
environment behave as the vibrational mode, which makes the electron to be
transitioned mainly with the so-called "vertical transitions" in the
conventional FC effect. The "vertical transition" for the central spin in the
spin environment manifests as, the certain collective spin states of the
environment is favored, which corresponds to the minimal change in the average
of the total spin angular momentum.Comment: 8 pages, 8 figure
Intraoperative and postoperative complications of gynecological laparoscopic interventions: incidence and risk factors
Purpose
The aims of this study were to determine the incidence of intraoperative and postoperative complications of laparoscopic gynecological interventions and to identify risk factors for such complications.
Methods
All patients who underwent laparoscopic interventions from September 2013 to September 2017 at the Department of Gynecology, Obstetrics and Reproductive Medicine, Saarland University Hospital were identified retrospectively using a prospectively compiled clinical database. Binary logistic regression analysis was used to identify independent risk factors for intra- and postoperative complications.
Results
Data from 3351 patients were included in the final analysis. Overall, 188 (5.6%) intraoperative and 219 (6.5%) postoperative complications were detected. On multivariate analysis, age [odds ratio (OR), 1.03; 95% confidence interval (CI) 1.01–1.04], surgery duration (OR, 1.02; 95% CI 1.02–1.03), carbon dioxide use (OR, 0.99; 95% CI 0.99–1.00), and surgical indication (all p ≤ 0.01) were independent risk factors for intraoperative and duration of surgery (OR, 1.01; 95% CI 1.01–1.02; p ≤ 0.01), carbon dioxide use (OR, 0.99; 95% CI 0.99–1.00; p ≤ 0.01), hemoglobin drop (OR, 1.41; 95% CI 1.21–1.65; p ≤ 0.01), and ASA status (p = 0.04) for postoperative complications.
Conclusion
In this large retrospective analysis with a generally low incidence of complications (5.6% intraoperative and 6.5% postoperative complications), a representative risk collective was identified: Patients aged > 38 years, surgery duration > 99 min, benign or malignant adnex findings were at higher risk for intraoperative and patients with surgery duration > 94 min, hemoglobin drop > 2 g/dl and ASA status III at higher risk for postoperative complications
Avalanche amplification of a single exciton in a semiconductor nanowire
Interfacing single photons and electrons is a crucial ingredient for sharing
quantum information between remote solid-state qubits. Semiconductor nanowires
offer the unique possibility to combine optical quantum dots with avalanche
photodiodes, thus enabling the conversion of an incoming single photon into a
macroscopic current for efficient electrical detection. Currently, millions of
excitation events are required to perform electrical read-out of an exciton
qubit state. Here we demonstrate multiplication of carriers from only a single
exciton generated in a quantum dot after tunneling into a nanowire avalanche
photodiode. Due to the large amplification of both electrons and holes (>
10^4), we reduce by four orders of magnitude the number of excitation events
required to electrically detect a single exciton generated in a quantum dot.
This work represents a significant step towards single-shot electrical read-out
and offers a new functionality for on-chip quantum information circuits
Teaching undergraduate students gynecological and obstetrical examination skills: the patient's opinion
Introduction Our study assesses the patients’ opinion about gynecological examination performed by undergraduate students
(UgSts). This assessment will be used in improving our undergraduate training program. A positive opinion would mean
a lower chance of a patient refusing to be examined by a tutor or student, taking into account vaginal examination (VE).
Materials and methods We performed a prospective cross-sectional survey on 1194 patients, consisting of outpatient and
inpatient at the departments of obstetrics and gynecology from November 2015 to May 2016. The questionnaire consisted
of 46 questions. Besides demographic data, we assessed the mindset of patients regarding the involvement of undergradu ate student (UgSt) in gynecological and obstetrical examinations. We used SPSS version 23 for the statistical analysis. For
reporting the data, we followed the STROBE statement of reporting observational studies.
Results The median age was 38 years having a median of one child. 34% presented due to obstetrical problems, 38% due to
gynecological complaints, and 19% due to known gynecological malignancies. Generally, we retrieved a positive opinion
of patients towards the involvement of students in gynecological and obstetrical examination under supervision in 2/3 of
the cases.
Conclusions There is no reason to exclude medical UgSts from gynecological and obstetrical examinations after obtaining
a written or oral consent
Increased neutrophil-lymphocyte ratio is a poor prognostic factor in patients with primary operable and inoperable pancreatic cancer
Background:
The neutrophil-lymphocyte ratio (NLR) has been proposed as an indicator of systemic inflammatory response. Previous findings from small-scale studies revealed conflicting results about its independent prognostic significance with regard to different clinical end points in pancreatic cancer (PC) patients. Therefore, the aim of our study was the external validation of the prognostic significance of NLR in a large cohort of PC patients.
Methods:
Data from 371 consecutive PC patients, treated between 2004 and 2010 at a single centre, were evaluated retrospectively. The whole cohort was stratified into two groups according to the treatment modality. Group 1 comprised 261 patients with inoperable PC at diagnosis and group 2 comprised 110 patients with surgically resected PC. Cancer-specific survival (CSS) was assessed using the Kaplan–Meier method. To evaluate the independent prognostic significance of the NLR, the modified Glasgow prognostic score (mGPS) and the platelet-lymphocyte ratio univariate and multivariate Cox regression models were applied.
Results:
Multivariate analysis identified increased NLR as an independent prognostic factor for inoperable PC patients (hazard ratio (HR)=2.53, confidence interval (CI)=1.64–3.91, P<0.001) and surgically resected PC patients (HR=1.61, CI=1.02–2.53, P=0.039). In inoperable PC patients, the mGPS was associated with poor CSS only in univariate analysis (HR=1.44, CI=1.04–1.98).
Conclusion:
Risk prediction for cancer-related end points using NLR does add independent prognostic information to other well-established prognostic factors in patients with PC, regardless of the undergoing therapeutic modality. Thus, the NLR should be considered for future individual risk assessment in patients with PC
Canopy bird assemblages are less influenced by habitat age and isolation than understory bird assemblages in Neotropical secondary forest
Secondary forest habitats are increasingly recognized for their potential to conserve biodiversity in the tropics. However, the development of faunal assemblages in secondary forest systems varies according to habitat quality and species‐specific traits. In this study, we predicted that the recovery of bird assemblages is dependent on secondary forest age and level of isolation, the forest stratum examined, and the species’ traits of feeding guild and body mass. This study was undertaken in secondary forests in central Panama; spanning a chronosequence of 60‐, 90‐, and 120‐year‐old forests, and in neighboring old‐growth forest. To give equal attention to all forest strata, we employed a novel method that paired simultaneous surveys in canopy and understory. This survey method provides a more nuanced picture than ground‐based studies, which are biased toward understory assemblages. Bird reassembly varied according to both habitat age and isolation, although it was challenging to separate these effects, as the older sites were also more isolated than the younger sites. In combination, habitat age and isolation impacted understory birds more than canopy‐dwelling birds. Proportions of dietary guilds did not vary with habitat age, but were significantly different between strata. Body mass distributions were similar across forest ages for small‐bodied birds, but older forest supported more large‐bodied birds, probably due to control of poaching at these sites. Canopy assemblages were characterized by higher species richness, and greater variation in both dietary breadth and body mass, relative to understory assemblages. The results highlight that secondary forests may offer critical refugia for many bird species, particularly specialist canopy‐dwellers. However, understory bird species may be less able to adapt to novel and isolated habitats and should be the focus of conservation efforts encouraging bird colonization of secondary forests
Decrease in treatment intensity predicts worse outcome in patients with locally advanced head and neck squamous cell carcinoma undergoing radiochemotherapy
PURPOSE: Radiochemotherapy (RCT) is an effective standard therapy for locally advanced head and neck squamous cell carcinoma (LA-HNSCC). Nonetheless, toxicity is common, with patients often requiring dose modifications. METHODS: To investigate associations of RCT toxicities according to CTCAE version 5.0 and subsequent therapy modifications with short- and long-term treatment outcomes, we studied all 193 patients with HNSCC who received RCT (70 Gy + platinum agent) at an academic center between 03/2010 and 04/2018. RESULTS: During RCT, 77 (41%, 95% CI 34-49) patients developed at least one ≥ grade 3 toxicity, including seven grade 4 and 3 fatal grade 5 toxicities. The most frequent any-grade toxicities were xerostomia (n = 187), stomatitis (n = 181), dermatitis (n = 174), and leucopenia (n = 98). Eleven patients (6%) had their radiotherapy schedule modified (mean radiotherapy dose reduction = 12 Gy), and 120 patients (64%) had chemotherapy modifications (permanent discontinuation: n = 67, pause: n = 34, dose reduction: n = 7, change to other chemotherapy: n = 10). Objective response rates to RCT were 55% and 88% in patients with and without radiotherapy modifications (p = 0.003), and 84% and 88% in patients with and without chemotherapy modifications (p = 0.468), respectively. Five-year progression-free survival estimates were 20% and 50% in patients with and without radiotherapy modifications (p = < 0.001), and 53% and 40% in patients with and without chemotherapy modifications (p = 0.88), respectively. CONCLUSIONS: Reductions of radiotherapy dose were associated with impaired long-term outcomes, whereas reductions in chemotherapy intensity were not. This suggests that toxicities during RCT should be primarily managed by modifying chemotherapy rather than radiotherapy
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