Thermal illumination limits in 3D Raman microscopy: A comparison of different sample illumination strategies to obtain maximum imaging speed

Confocal Raman microscopy is a powerful tool for material science and biomedical research. However, the low Raman scattering cross-section limits the working speed, which reduces the applicability for large and sensitive samples. Here, we discuss the fundamental physical limits of Raman spectroscopy with respect to signal-to-noise, sample load and how to achieve maximal imaging speed. For this, we develop a simple model to describe arbitrary far field light microscopes and their thermal influence on the sample. This model is used to compare the practical applicability of point- and line-confocal microscopes as well as wide-field-, light sheet- and light line illumination, for the measurement of 3D biological samples. The parallelization degree of the illumination can positively affect the imaging speed as long as it is not limited by thermal sample heating. In case of heat build-up inside the sample, the advantages of parallelization can be lost due to the required attenuation of excitation and the working speed can drop below that of a sequential method. We show that for point like illumination, the exposure time is thermally not as critical for the sample as the irradiance, while for volume like illumination, the exposure time and irradiance result in the same thermal effect. The results of our theoretical study are experimentally confirmed and suggest new concepts of Raman microscopy, thus extending its applicability. The developed model can be applied to Raman imaging as well as to other modes (e.g. two- or three- photon imaging, STED, PALM/STORM, MINFLUX) where thermal effects impose a practical limit due to the high irradiance required

ATP measurement as method to monitor the quality of reprocessing flexible endoscopes

Insufficient performance of cleaning and disinfection of flexible endoscopes can pose an infection risk to patients. Actually quality of reprocessing is checked by performing microbiological cultures. Unfortunately, their results are not available on the same day so that more rapid methods are desirable. We compared the ATP (adenosine triphosphate) bioluminescence for hygiene checking of the reprocessing procedures of 108 flexible endoscopes with routine microbiological culture technics. Sensitivity and specifity of ATP bioluminescence was calculated. 28 endoscopes showed bacterial growth of at least one sample. Depending on the applied threshold of bioluminescence between 67 and 28 endoscopes were positive. Sensitivity varied between 0.46 and 0.75 and specifity between 0.43 and 0.81. ATP bioluminescence does not replace routine microbiologic methods but it can indicate the need of immediate check of reprocessing

One-day point prevalence of emerging bacterial pathogens in four secondary and five tertiary care German hospitals – results from a pilot study of the German Society for Hospital Hygiene (Deutsche Gesellschaft für Krankenhaushygiene, DGKH)

Objective: Data on the prevalence of emerging bacterial pathogens like extended-spectrum-lactamase-building (ESBL) Gram negative organisms, multiresistant Pseudomonas and Acinetobacter species or toxin-building Clostridium difficile in German hospitals are sparse. To provide data for different regions in Germany, a one-day point prevalence study with five tertiary care hospitals and four secondary care hospitals was conducted on the 10th of February 2010

Confidence Testing of Shell 405 and S-405 Catalysts in a Monopropellant Hydrazine Thruster

As part of the transfer of catalyst manufacturing technology from Shell Chemical Company (Shell 405 catalyst manufactured in Houston, Texas) to Aerojet (S-405 manufactured in Redmond, Washington), Aerojet demonstrated the equivalence of S-405 and Shell 405 at beginning of life. Some US aerospace users expressed a desire to conduct a preliminary confidence test to assess end-of-life characteristics for S-405. NASA Marshall Space Flight Center (MSFC) and Aerojet entered a contractual agreement in 2004 to conduct a confidence test using a pair of 0.2-lbf MR-103G monopropellant hydrazine thrusters, comparing S-405 and Shell 405 side by side. This paper summarizes the formulation of this test program, explains the test matrix, describes the progress of the test, and analyzes the test results. This paper also includes a discussion of the limitations of this test and the ramifications of the test results for assessing the need for future qualification testing in particular hydrazine thruster applications

Refurbishment works in a hospital during normal operation

Background: Construction and renovation work in hospitals pose risks of fungal airborne infections for immunosuppressed patients. If possible, reconstruction work will be postponed to periods without patient treatment. However, in many situations urgent damage demands immediate refurbishment works before the transferring of patients to other wards or closure of wards is possible. Reported here are infection control related measures and implemented procedures after two incidents of water damage which occurred on a surgical ward and an intensive care unit at the University hospital of Essen

Hindfoot and Foot Arch Reconstruction by Atypical Subtalar Arthrodesis and Achilles Tendon Lengthening for a Severe Comminuted Calcaneal Fracture: A Case Report

Open calcaneus fractures are rare but severe injuries. Highenergy trauma often causes significant soft tissue and bone damage, posing extraordinary challenges for treatment.3 The rates of complications associated with treatment are high, including malunion, nonunion, and fracture-related infections.5 These complications are associated with an amputation rate of the lower limb of 8%.2 Even if amputation is avoided and treatment and complication management are successful, the patient’s quality of life is compromised, similar to those suffering from bone infections in the long bones. Apart from compromised soft tissue, bone defects present the main obstacle to successful treatment. Anatomical bone reconstruction becomes difficult, if not impossible, in cases of severe compound fractures. Open fractures necessitate thorough surgical debridement to prevent infection, which may result in significant bone defects requiring bone reconstruction.3,4 Given the immense challenges of surgical treatment following high-energy injuries, where bone transplantation and extensive osteosynthesis offer limited promise, we present a case illustrating an atypical subtalar arthrodesis and hindfoot reconstruction in a patient with a Gustilo type IIIa° comminuted calcaneus fracture

Treatment of severely open tibial fractures, non-unions, and fracture-related infections with a gentamicin-coated tibial nail—clinical outcomes including quality of life analysis and psychological ICD-10-based symptom rating

Background Implant-associated infections depict a major challenge in orthopedics and trauma surgery putting a high burden on the patients and health care systems, strongly requiring improvement of infection prevention and of clinical outcomes. One strategy includes the usage of antimicrobial-coated implants. We evaluated outcomes after surgical treatment using a gentamicin-coated nail on (i) treatment success in terms of bone consolidation, (ii) absence of infection, and (iii) patient-reported quality of life in a patient cohort with high risk of infection/reinfection and treatment failure. Methods Thirteen patients with open tibia fractures (n = 4), non-unions (n = 2), and fracture-related infection (n = 7) treated with a gentamicin-coated intramedullary nail (ETN ProtectTM) were retrospectively reviewed. Quality of life was evaluated with the EQ-5D, SF-36, and with an ICD-10-based symptom rating (ISR). Results At a mean follow-up of 2.8 years, 11 of the 13 patients (84.6%) achieved bone consolidation without any additional surgical intervention, whereas two patients required a revision surgery due to infection and removal of the implant. No specific implant-related side effects were noted. Quality of life scores were significantly lower compared to a German age-matched reference population. The mean ISR scores revealed mild psychological symptom burden on the scale depression. Conclusion The use of a gentamicin-coated intramedullary nail seems to be reasonable in open fractures and revision surgery for aseptic non-union or established fracture-related infection to avoid infection complications and to achieve bony union. Despite successful treatment of challenging cases with the gentamicin-treated implant, significantly reduced quality of life after treatment underlines the need of further efforts to improve surgical treatment strategies and psychological support

Tuning the corona-core ratio of polyplex micelles for selective oligonucleotide delivery to hepatocytes or hepatic immune cells

Targeted delivery of oligonucleotides or small molecular drugs to hepatocytes, the liver's parenchymal cells, is challenging without targeting moiety due to the highly efficient mononuclear phagocyte system (MPS) of the liver. The MPS comprises Kupffer cells and specialized sinusoidal endothelial cells, efficiently clearing nanocarriers regardless of their size and surface properties. Physiologically, this non-parenchymal shield protects hepatocytes; however, these local barriers must be overcome for drug delivery. Nanocarrier structural properties strongly influence tissue penetration, in vivo pharmacokinetics, and biodistribution profile. Here we demonstrate the in vivo biodistribution of polyplex micelles formed by polyion complexation of short interfering (si)RNA with modified poly(ethylene glycol)-block-poly(allyl glycidyl ether) (PEG-b-PAGE) diblock copolymer that carries amino moieties in the side chain. The ratio between PEG corona and siRNA complexed PAGE core of polyplex micelles was chemically varied by altering the degree of polymerization of PAGE. Applying Raman-spectroscopy and dynamic in silico modeling on the polyplex micelles, we determined the corona-core ratio (CCR) and visualized the possible micellar structure with varying CCR. The results for this model system reveal that polyplex micelles with higher CCR, i.e., better PEG coverage, exclusively accumulate and thus allow passive cell-type-specific targeting towards hepatocytes, overcoming the macrophage-rich reticuloendothelial barrier of the liver

Mice with renal-specific alterations of stem cell-associated signaling develop symptoms of chronic kidney disease but surprisingly no tumors

Previously, we found that Wnt and Notch signaling govern stem cells of clear cell kidney cancer (ccRCC) in patients. To mimic stem cell responses in the normal kidney in vitro in a marker-unbiased fashion, we have established tubular organoids (tubuloids) from total single adult mouse kidney epithelial cells in Matrigel and serum-free conditions. Deep proteomic and phosphoproteomic analyses revealed that tubuloids resembled renewal of adult kidney tubular epithelia, since tubuloid cells displayed activity of Wnt and Notch signaling, long-term proliferation and expression of markers of proximal and distal nephron lineages. In our wish to model stem cell-derived human ccRCC, we have generated two types of genetic double kidney mutants in mice: Wnt-β-catenin-GOF together with Notch-GOF and Wnt-β-catenin-GOF together with a most common alteration in ccRCC, Vhl-LOF. An inducible Pax8-rtTA-LC1-Cre was used to drive recombination specifically in adult kidney epithelial cells. We confirmed mutagenesis of β-catenin, Notch and Vhl alleles on DNA, protein and mRNA target gene levels. Surprisingly, we observed symptoms of chronic kidney disease (CKD) in mutant mice, but no increased proliferation and tumorigenesis. Thus, the responses of kidney stem cells in the tubuloid and genetic systems produced different phenotypes, i.e. enhanced renewal versus CKD

Infliximab Reduces Endoscopic, but Not Clinical, Recurrence of Crohn's Disease After Ileocolonic Resection

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