499 research outputs found
A spiraled segmented waveguide sensor: Principle and experiment
A novel type of chemo-optical sensor has been designed, fabricated and characterized. The sensor is simple to fabricate, puts low demands on light source quality and shows resolution of index changes of ~ $3.10^{-8}
Laparoscopic Resection of Residual Retroperitoneal Tumor Mass in Advanced Nonseminomatous Testicular Germ Cell Tumors; a Feasible and Safe Oncological Procedure
Ten-year oncological experience of the University Medical Center Groningen with conventional laparotomy (C-RRRTM) and laparoscopy (L-RRRTM) is described concerning resection of residual retroperitoneal tumor masses (RRTM) in a large series of patients with advanced nonseminomatous testicular germ cell tumors (NSTGCT). 150 consecutive patients with disseminated NSTGCT required adjunctive surgery after combination chemotherapy. L-RRRTM was scheduled in 89 and C-RRRTM in 61 patients. Median residual tumor diameter was 20 mm in the L-RRRTM versus 42 mm in the C-RRRTM group (p <0.001). Conversion rate was 15% in the L-RRRTM group. Perioperative complications occurred in 5 patients (6%) in the L-RRRTM and 7 (12%, NS) in the C-RRRTM group. Median duration of L-RRRTM was 156 minutes vs. 221 minutes for C-RRRTM (p <0.001). 17/89 patients in the L-RRRTM group had postoperative complications versus 18/61 patients in the C-RRRTM group (NS). Median postoperative stay in the L-RRRTM group was 2 vs. 6 days in the C-RRRTM group (p <0.001). During a median follow-up of 79 months, 27 patients had recurrences: 8 (9%) in the L-RRRTM group and 19 (31%) in the C-RRRTM group (p <0.001). Laparoscopic resection of RRTM for advanced NSTGCT is feasible and an oncologically safe option in appropriately selected patients
Screening for germline DND1 mutations in testicular cancer patients
Although several observations suggest that a strong genetic predisposition to developing testicular germ cell tumors (TGCT) exists, no associated, highly penetrant germline mutations have been identified so far. In the 129/Sv mouse strain, a germline mutation in the DND1 gene has been shown to strongly increase the TGCT risk. We screened 272 men with TGCT (89% sporadic cases, 11% familial) for germline mutations in the human homologue of DND1. A single nucleotide substitution c.657C > G (p.Asp219Glu) was observed in a non-familial case of testicular embryonal carcinoma. The variant was also present in the patient’s asymptomatic father and two brothers, but not observed in 210 control chromosomes. The wild type DND1 allele was not lost in the patient’s tumor. In silico analysis of the variant predicts it to be non-pathogenic. We conclude that germline DND1 mutations are unlikely to contribute significantly to human testicular germ cell tumor susceptibility. The role of human DND1 in normal physiology and disease, however, is still virtually unknown and it therefore warrants further research
Spectropolarimetry of 3CR 68.1: A Highly Inclined Quasar
We present Keck spectropolarimetry of the highly polarized radio-loud quasar
3CR 68.1 (z=1.228, V=19). The polarization increases from 5 in the red (4000 A
rest-frame) to >10% in the blue (1900 A rest-frame). The broad emission lines
are polarized the same as the continuum, which shows that 3CR 68.1 is not a
blazar as it has sometimes been regarded in the past. We also present
measurements of the emission lines and a strong, blueshifted, associated
absorption line system, as well as a detection at the emission-line redshift of
Ca II K absorption, presumably from stars in the host galaxy. 3CR 68.1 belongs
to an observationally rare class of highly polarized quasars that are neither
blazars nor partially obscured radio-quiet QSOs. Taking into account 3CR 68.1's
other unusual properties, such as its extremely red spectral energy
distribution and its extreme lobe dominance, we explain our spectropolarimetric
results in terms of unified models. We argue that we have a dusty, highly
inclined view of 3CR 68.1, with reddened scattered (polarized) quasar light
diluted by even more dust-reddened quasar light reaching us directly from the
nucleus.Comment: 20 pages, includes 3 tables, 6 figures. Accepted by Ap
Morbidity After Inguinal Lymph Node Dissections:It Is Time for a Change
Inguinal lymph node dissection (ILND) for stage 3 melanoma is accompanied by high wound complication rates. During the past decades, several changes in perioperative care have been instituted to decrease the incidence of these complications. This study aimed to evaluate the effect of these different care protocols on wound complications after ILND. A retrospective analysis of prospectively collected data was performed with 240 patients who underwent an ILND in the University Medical Center Groningen between 1989 and 2014. Four groups with different treatment protocols were analyzed: A (>= 10 days of bed rest with a Bohler Braun splint), B (10 days of bed rest without a splint), C (5 days of bed rest), and D (1 day of bed rest). The effect of early mobilization, abolishment of the Bohler Braun splint and postural restrictions, and the introduction of prophylactic antibiotics were analyzed. One or more wound complications occurred in 51.2 % of the patients including wound infection (29.8 %), seroma (21.5 %), wound necrosis (13.6 %), and hematoma (5 %). In consecutive periods, respectively 44.4, 60.3, 44.9 and 55.2 % of the patients experienced wound complications. None of the instituted changes in protocols led to a decrease in wound complications. Changes in perioperative care protocols did not affect the rate of wound complications. Perhaps a change in the surgical procedure itself can lead to the necessary reduction of wound complications after ILND
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Evolutionary biology for the 21st century
New theoretical and conceptual frameworks are required for evolutionary biology to capitalize on the wealth of data now becoming available from the study of genomes, phenotypes, and organisms - including humans - in their natural environments.Molecular and Cellular BiologyOrganismic and Evolutionary Biolog
Planet Hunters. V. A Confirmed Jupiter-Size Planet in the Habitable Zone and 42 Planet Candidates from the Kepler Archive Data
We report the latest Planet Hunter results, including PH2 b, a Jupiter-size
(R_PL = 10.12 \pm 0.56 R_E) planet orbiting in the habitable zone of a
solar-type star. PH2 b was elevated from candidate status when a series of
false positive tests yielded a 99.9% confidence level that transit events
detected around the star KIC 12735740 had a planetary origin. Planet Hunter
volunteers have also discovered 42 new planet candidates in the Kepler public
archive data, of which 33 have at least three transits recorded. Most of these
transit candidates have orbital periods longer than 100 days and 20 are
potentially located in the habitable zones of their host stars. Nine candidates
were detected with only two transit events and the prospective periods are
longer than 400 days. The photometric models suggest that these objects have
radii that range between Neptune to Jupiter. These detections nearly double the
number of gas giant planet candidates orbiting at habitable zone distances. We
conducted spectroscopic observations for nine of the brighter targets to
improve the stellar parameters and we obtained adaptive optics imaging for four
of the stars to search for blended background or foreground stars that could
confuse our photometric modeling. We present an iterative analysis method to
derive the stellar and planet properties and uncertainties by combining the
available spectroscopic parameters, stellar evolution models, and transiting
light curve parameters, weighted by the measurement errors. Planet Hunters is a
citizen science project that crowd-sources the assessment of NASA Kepler light
curves. The discovery of these 43 planet candidates demonstrates the success of
citizen scientists at identifying planet candidates, even in longer period
orbits with only two or three transit events.Comment: 35 pages, 11 figures, 6 tables, accepted and published on ApJ ApJ,
776, 1
Innovation and experiential knowledge in firm exports: Applying the initial U-model
AbstractFocusing on firm export activity as an important field within international business, this study corroborates the importance of experiential knowledge as the initial Uppsala model predicts. The model builds on the belief that experiential knowledge minimizes the risk and uncertainty of export operations. Additionally, the article examines a firm's capacity to widen this knowledge through its dynamic capacities, honing in on a firm's learning function. Thus, this article analyzes the role of innovation in exporting by investigating export product innovation and export market innovation, both strategic activities that allow experiential knowledge acquisition. The article uses a firm-level official dataset from a small developing country, Chile, examining data from 2006 to 2011. The results indicate, firstly, that experiential knowledge resulting from exporting to different and geographically distant markets increases the firm's export activity. Secondly, such export market innovation takes precedence over export product innovation
Investigation of gene–environment interactions in relation to tic severit
Tourette syndrome (TS) is a neuropsychiatric disorder with involvement of genetic and environmental factors. We investi gated genetic loci previously implicated in Tourette syndrome and associated disorders in interaction with pre- and perinatal
adversity in relation to tic severity using a case-only (N=518) design. We assessed 98 single-nucleotide polymorphisms
(SNPs) selected from (I) top SNPs from genome-wide association studies (GWASs) of TS; (II) top SNPs from GWASs
of obsessive–compulsive disorder (OCD), attention-defcit/hyperactivity disorder (ADHD), and autism spectrum disorder
(ASD); (III) SNPs previously implicated in candidate-gene studies of TS; (IV) SNPs previously implicated in OCD or ASD;
and (V) tagging SNPs in neurotransmitter-related candidate genes. Linear regression models were used to examine the main
efects of the SNPs on tic severity, and the interaction efect of these SNPs with a cumulative pre- and perinatal adversity
score. Replication was sought for SNPs that met the threshold of signifcance (after correcting for multiple testing) in a rep lication sample (N=678). One SNP (rs7123010), previously implicated in a TS meta-analysis, was signifcantly related to
higher tic severity. We found a gene–environment interaction for rs6539267, another top TS GWAS SNP. These fndings were
not independently replicated. Our study highlights the future potential of TS GWAS top hits in gene–environment studies
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