Theory of quantum frequency conversion and type-II parametric down-conversion in the high-gain regime

Frequency conversion (FC) and type-II parametric down-conversion (PDC) processes serve as basic building blocks for the implementation of quantum optical experiments: type-II PDC enables the efficient creation of quantum states such as photon-number states and Einstein-Podolsky-Rosen-states (EPR-states). FC gives rise to technologies enabling efficient atom-photon coupling, ultrafast pulse gates and enhanced detection schemes. However, despite their widespread deployment, their theoretical treatment remains challenging. Especially the multi-photon components in the high-gain regime as well as the explicit time-dependence of the involved Hamiltonians hamper an efficient theoretical description of these nonlinear optical processes. In this paper, we investigate these effects and put forward two models that enable a full description of FC and type-II PDC in the high-gain regime. We present a rigorous numerical model relying on the solution of coupled integro-differential equations that covers the complete dynamics of the process. As an alternative, we develop a simplified model that, at the expense of neglecting time-ordering effects, enables an analytical solution. While the simplified model approximates the correct solution with high fidelity in a broad parameter range, sufficient for many experimental situations, such as FC with low efficiency, entangled photon-pair generation and the heralding of single photons from type-II PDC, our investigations reveal that the rigorous model predicts a decreased performance for FC processes in quantum pulse gate applications and an enhanced EPR-state generation rate during type-II PDC, when EPR squeezing values above 12 dB are considered.Comment: 26 pages, 4 figure

Keratinocytic epidermal nevi are associated with mosaic RAS mutations

Background: Activating RAS mutations in the germline cause rare developmental disorders such as Costello syndrome. Somatic RAS mutations are found in approximately 30% of human cancers. Keratinocytic epidermal nevi (KEN) represent benign congenital skin lesions arranged along Blaschko's lines. A subgroup of KEN is caused by hotspot oncogenic FGFR3 and PIK3CA mutations in mosaicism, but the majority lack these mutations. Methods: This study screened 72 KEN for activating mutations in RAS genes and other oncogenes. Results: Activating RAS mutations were identified in 28/72 (39%) of KEN. HRAS was the most commonly affected oncogene (86%), with the HRAS p.G13R substitution representing a new hotspot mutation. Conclusion: These results indicate that activating RAS somatic mutations leading to mosaicism result in benign KEN of the skin. Given the prevalence of KEN, mosaic HRAS mutations appear to be more common in patients than germline ones. These findings identify KEN as a mosaic RASopathy and lend further support to the notion that genetic mosaicism is an important contributor to disease

Antibacterial Effect of a 4x Cu-TiO2 Coating Simulating Acute Periprosthetic Infection—An Animal Model

The purpose of our study was to investigate the antibacterial effect of a spacer (Ti6Al4V) coated with 4x Cu-TiO2 in an animal model simulating an acute periprosthetic infection by Staphylococcus aureus. Ti6Al4 bolts contaminated with Staphylococcus aureus were implanted into the femoral condyle of rabbits (n = 36) divided into 3 groups. After one week in group 1 (control) the bolts were removed without any replacement. In group2 Ti6Al4V bolts with a 4x Cu-TiO2 coating and in group 3 beads of a gentamicin-PMMA chain were imbedded into the borehole. Microbiological investigation was performed at the primary surgery, at the revision surgery and after scarification of the rabbits 3 weeks after the first surgery. Blood tests were conducted weekly. The initial overall infection rate was 88.9%. In group 2 and 3 a significant decrease of the infection rate was shown in contrast to the control group. The C-reactive protein (CRP) levels declined one week after the first surgery except in the control group where the CRP level even increased. This is the first in vivo study that demonstrated the antibacterial effects of a fourfold Cu-TiO2 coating. For the future, the coating investigated could be a promising option in the treatment of implant-associated infections

Partial hepatectomy accelerates colorectal metastasis by priming an inflammatory premetastatic niche in the liver

BackgroundResection of colorectal liver metastasis is the standard of care for patients with Stage IV CRC. Despite undoubtedly improving the overall survival of patients, pHx for colorectal liver metastasis frequently leads to disease recurrence. The contribution of this procedure to metastatic colorectal cancer at a molecular level is poorly understood. We designed a mouse model of orthograde metastatic colorectal cancer (CRC) to investigate the effect of partial hepatectomy (pHx) on tumor progression.MethodsCRC organoids were implanted into the cecal walls of wild type mice, and animals were screened for liver metastasis. At the time of metastasis, 1/3 partial hepatectomy was performed and the tumor burden was assessed longitudinally using MRI. After euthanasia, different tissues were analyzed for immunological and transcriptional changes using FACS, qPCR, RNA sequencing, and immunohistochemistry.ResultsMice that underwent pHx presented significant liver hypertrophy and an increased overall metastatic load compared with SHAM operated mice in MRI. Elevation in the metastatic volume was defined by an increase in de novo liver metastasis without any effect on the growth of each metastasis. Concordantly, the livers of pHx mice were characterized by neutrophil and bacterial infiltration, inflammatory response, extracellular remodeling, and an increased abundance of tight junctions, resulting in the formation of a premetastatic niche, thus facilitating metastatic seeding.ConclusionsRegenerative pathways following pHx accelerate colorectal metastasis to the liver by priming a premetastatic niche

Chromophores in operative surgery: Current practice and rationalized development

BackgroundChromophore-containing molecules feature extensively in surgical practice, with synthetic dyes gaining popularity over endogenous optical adjuncts. New applications for chromophores in diagnostics and operative treatment exploit unique chemical structures suited for illuminating target tissues beyond the visual spectrum, ranging from ultraviolet (UV) to near-infrared (NIR). This review outlines the rationale for surgical chromophore application, the weaknesses and risks in each class of these compounds, and areas of foreseeable potential for employment of specialized contrast agents.MethodAn English-language literature search applied the following Boolean Search String: “dye OR Lake OR Stain OR chromophore” AND “tox$OR terato* OR carcino$ OR Allerg$OR surg$ OR clinic” using EMBASE, PUBMED, PUBMED central and OVIDSp, with back-referencing through Web of Knowledge™.ResultsBased on the primary literature, this study proposes a surgically relevant classification system of chromophores in current use, which facilitates risk/benefit consideration for the surgeon who employs them, and which facilitates clinically oriented development.ConclusionsThe next stage of development for optically active surgical adjuncts must address practical constraints whilst minimizing risks of adverse effects. Exploiting the technology's full potential also requires improvements in the usefulness of imagery equipment

Identification of new genes associated with melanoma

Purpose: Repeated failures in melanoma therapy made clear that the molecular mechanisms leading to melanoma are still poorly understood. Here, we aim to provide a more comprehensive understanding of the transcriptional profiles and signaling pathways associated with melanoma. Methods: Gene expression was analyzed using the Affymetrix Human Genome U133A 2.0 GeneChip arrays. To avoid culture artifacts, we used microdissected fresh frozen material of 18 melanocytic nevi (MN), 20 primary melanomas (PM) and 20 metastatic melanomas (MM). Statistical analysis was performed with Genomatix Chipinspector, Ingenuity™ Software, SPSS Software and Partek Genomic Suite 6.4. Expression levels of selected transcripts were verified by quantitative real-time RT-PCR and immunostaining of a tissue microarray sampling more than 280 cases of MN, PM, and MM with known clinical outcome. Results: A total of 284 differentially expressed genes was detected in PM compared to MN and 189 genes in MM compared to PM affecting common cancer pathways such as MAPK-, Wnt-, and Notch-signaling. Using principal component analysis, the samples could be grouped according to their histological entity. We identified a panel of novel melanoma-associated markers: FRZB, an antagonist of Wnt; TLE1, a transcription factor partner of TCF/LEF-1; CNTN1, an activator of Notch signaling; two Serpin peptidase inhibitors, Serpin B3/B4, and the TGF-β family member GDF15, the latter with association to MAPK-signaling

Cardiogram: Visual analytics for automotive engineers

We present Cardiogram, a visual analytics system that supports automotive engineers in debugging masses of traces each consisting of millions of recorded messages from in-car communication networks. With their increasing complexity, ensuring these safety-critical networks to be error-free has become a major task and challenge for automotive engineers. To overcome shortcomings of current analysis tools, Cardiogram combines visualization techniques with a data preprocessing approach to automatically reduce complexity based on engineers ’ domain knowledge. In this paper, we provide the findings from an exploratory, three-year field study within a large automotive company, studying current practices of engineers, the challenges they meet and the characteristics for integrating novel visual analytics tools into their work practices. We then introduce Cardiogram, discuss how our field analysis influenced our design decisions, and present a qualitative, long-term, in-depth evaluation. Results of this study showed that our participants successfully used Cardiogram to increase the amount of analyzable information, to externalize domain knowledge, and to provide new insights into trace data. Our design approach finally led to the adoption of Cardiogram into engineers ’ daily practices

Concomitant Sternal Fracture in Flail Chest: An Analysis of 21,741 Polytrauma Patients from the TraumaRegister DGU (R)

Background Isolated sternal fractures (SFs) rarely show complications, but their influence in a thorax trauma of the seriously injured still remains unclear. Methods A retrospective analysis of the TraumaRegister DGU (R) was performed involving the years 2009 to 2013 (Injury Severity Score [ISS] >= 16, primary admission to a trauma center). Cohort formation: Unilateral and bilateral flail chest (FC) injuries with and without a concomitant SF, respectively. Results In total, 21,741 patients (25% female) met the inclusion criteria, with 3,492 (16.1%) showing SF. Unilateral FC patients were on average 53.6 +/- 18.4 years old, and bilateral FC patients were on average 55.2 +/- 17.7 years old. The ISS in unilateral FC and bilateral FC amounted to 31.2 +/- 13.0 and 43.4 +/- 13.1 points, respectively. FC with an SF occurredmore frequently as an injury to car occupants and less frequently as an injury to motorcyclists or in injuries due to falls. Conclusion Patients with an SF additional to an FC had longer hospital and intensive care unit stays and were longer artificially respirated than those patients without an SF. SF indicates possible cardiac and thoracic spine injuries