Endoscopic vacuum therapy in the upper gastrointestinal tract: when and how to use it

BACKGROUND Endoscopic vacuum therapy (EVT) has emerged as a novel treatment option for upper gastrointestinal wall defects. The basic principle of action of EVT entails evacuation of secretions, removal of wound debris, and containment of the defect. Furthermore, there is increasing evidence that EVT reduces interstitial edema, increases oxygen saturation, and promotes tissue granulation and microcirculation. Various devices, such as macroporous polyurethane sponge systems or open-pore film drains, have been developed for specific indications. Depending on the individual situation, EVT devices can be placed in- or outside the intestinal lumen, as a stand-alone procedure, or in combination with surgical, radiological, and other endoscopic interventions. PURPOSE The aim of this narrative review is to describe the current spectrum of EVT in the upper gastrointestinal tract and to assess and summarize the related scientific literature. CONCLUSIONS There is growing evidence that the efficacy of EVT for upper GI leakages exceeds that of other interventional treatment modalities such as self-expanding metal stents, clips, or simple drainages. Owing to the promising results and the excellent risk profile, EVT has become the therapy of choice for perforations and anastomotic leakages of the upper gastrointestinal tract in many centers of expertise. In addition, recent clinical research suggests that preemptive use of EVT after high-risk upper gastrointestinal resections may play an important role in reducing postoperative morbidity

Parameterstudie zur Simulation von Niedertemperatur-Kreisprozessen (KIT Scientific Report ; 7585)

Bei der geothermischen Stromerzeugung wird warmes Wasser aus tiefen Gesteinsschichten gepumpt und über einen Niedertemperatur-Kreisprozess zu elektrischem Strom gewandelt. Üblicherweise erfolgt die Stromerzeugung aufgrund der geringen Temperaturen über einen ORC-Prozess (Organic-Rankine-Cycle). Im Rahmen dieser Arbeit wurde das Potential von unter- und überkritischen Niedertemperatur-Prozessen mit verschiedenen Arbeitsmitteln untersucht

Thermodynamische Auslegung und transiente Simulation eines überkritischen Organic Rankine Cycles für einen leistungsoptimierten Betrieb (KIT Scientific Reports ; 7674)

Niedertemperaturwärme im Bereich von 100 °C - 200 °C kann mittels Organic Rankine Cycles (ORC) zur Stromproduktion genutzt werden. Zur Untersuchung von Optimierungsmöglichkeiten bei ORC-Prozessen wird am KIT die Testanlage MoNiKa (Modularer Niedertemperaturkreis Karlsruhe) aufgebaut. Diese Arbeit beinhaltet eine thermodynamische Auslegung des Prozesses und darauf aufbauend die Implementierung eines dynamischen Simulationsmodells, das eine detaillierte Analyse des Teillastverhaltens ermöglicht

Photon-Upconverting Materials: Advances and Prospects for Various Emerging Applications

Rare-earth-doped upconversion materials, featuring exceptional photophysical properties including long lifetime, sharp emission lines, large anti-Stokes shift, low autofluorescence of the background, and low toxicity, are promising for many applications. These materials have been investigated extensively since the 1960s and employed in many optical devices. However, due to rapid development of synthesis strategies for nanomaterials, upconversion materials have been rehighlighted on the basis of nanotechnology. Herein, we discuss the recent advances in upconversion materials. We start by considering energy transfer processes involved in the basic study of upconversion emission phenomena, as well as synthesis strategies of these materials. Progress in different energy transfer processes, which play an important role in determining luminescence efficiency, is then discussed. Newer applications of these materials have been vastly reviewed

Development Towards Improved Durability Of Implanted Neuroprosthetic Electrodes Through Surface Modifications

Indiana University-Purdue University Indianapolis (IUPUI)The present thesis was completed to satisfy two functions in our laboratory: (1) explore carbon-black (CB) as an additive for electrodeposited intrinsically conductive polymers (ICPs) to improve electrical properties across the electrode-electrolyte interface for use in neuromodulation; and (2) design a histology protocol that will analyze peripheral nerve system (PNS) tissue following implantation of conventional metal and modified conventional metal electrodes with the ICP poly(3,4-ethylenedioxythiophere):poly(styrenesulfonate)/carbon-black (PEDOT:PSS/CB). It would appear that the functions explored may seem unrelated, however, these two topics play a crucial role in designing a viable electrode for use in acute and chronic neuromodulation and the subsequent analysis required to determine the mechanical properties and overall biocompatibility of design. A series of experiments with different PEDOT:PSS solutions containing varying amounts of suspended CB (n=19; 0 mg/mL to 2 mg/mL) were explored. Solutions were characterized using cyclic voltammetry (CV) using the intended electrode for deposition, composed of stainless-steel (SS), as the working electrode (WE) to determine respective redox potentials. SS was chosen because of its inherently bad electrochemical properties, meaning that improved functionality post electrodeposition would be easy to identify. Immediately following CV, stainless-steel electrodes were electrodeposited using one of two techniques: (1) potentiostat, allowing the cell to rest at the redox potential required for bipolaron formation (0.9 V); or (2) galvanostat, where the electrode was submitted to a constant current of 200 mA and allowed to coat. Rapid electrochemical impedance spectroscopy was performed prior to and immediately following coating to determine the pre-electrochemical and post-electrochemical impedance characteristics. Results indicate that there was a positive relationship between the amount of CB additive and the relative impedance drop between the uncoated and coated counterparts. Furthermore, the modified electrochemical interfaces are substantially improved for use in frequency ranges of 10 Hz to 50 kHz, which encompass the ranges of our labs recently discovered low frequency alternating current (LFAC) for use in neuromodulation; thus indicating that PEDOT:PSS/CB modification may be used to improve impedance characteristics during our future LFAC experiments. This protocol, the one that contains the ideal concentration of carbon-black, was then recorded and will be used in our lab. Histology protocols were developed to improve our labs capabilities of post-mortem analysis of PNS tissue. Processing and embedding preparations that explored included paraffin, acrylic, and frozen. Subsequently, staining protocols were developed; however, they varied as a function of the embedding media used; staining protocols developed incorporated progressive and regressive hematoxylin and eosin (H&E) staining as well as toluidine blue (TB). Tissue was sectioned and observed using light microscopy

Hiatus hernia repair with a new-generation biosynthetic mesh: a 4-year single-center experience

BACKGROUND: Mesh augmentation is a highly controversial adjunct of hiatus hernia (HH) surgery. The current scientific evidence remains unclear and even experts disagree on indications and surgical techniques. With an aim to avoid the downsides of both non-resorbable synthetic and biological materials, biosynthetic long-term resorbable meshes (BSM) have recently been developed and are becoming increasingly popular. In this context, we aimed at assessing outcomes after HH repair with this new generation of mesh at our institution. METHODS: From a prospective database, we identified all consecutive patients that underwent HH repair with BSM augmentation. Data was extracted from electronic patient charts of our hospital information system. Endpoints of this analysis included perioperative morbidity, functional results and recurrence rates at follow-up. RESULTS: Between December 2017 and July 2022, 97 patients (elective primary cases n = 76, redo cases n = 13, emergency cases n = 8) underwent HH with BSM augmentation. Indications in elective and emergency cases were paraesophageal (Type II-IV) HH in 83%, and large Type I HH in 4%. There was no perioperative mortality, and overall (Clavien-Dindo ≥ 2) and severe (Clavien-Dindo ≥ 3b) postoperative morbidity was 15% and 3%, respectively. An outcome without postoperative complications was achieved in 85% of cases (elective primary surgery 88%, redo cases 100%, emergencies cases 25%). After a median (IQR) postoperative follow-up of 12 months, 69 patients (74%) were asymptomatic, 15 (16%) reported improvement, and 9 (10%) had clinical failure, of which 2 patients (2%) required revisional surgery. CONCLUSION: Our data suggest that HH repair with BSM augmentation is feasible and safe with low perioperative morbidity and acceptable postoperative failure rates at early to mid-term follow-up. BSM may be a useful alternative to non-resorbable materials in HH surgery

Artificial neural network for fast and versatile model parameter adjustment utilizing PAT signals of chromatography processes for process control under production conditions

Preparative chromatography is a well-established operation in chemical and biotechnology manufacturing. Chromatography achieves high separation performances, but often has to deal with the yield versus purity trade-off as the optimization criterium regarding through-put. The initial trade-off is often disturbed by the well-known phenomenon of chromatogram shifts over process lifetime, and has to be corrected by operators via adjustment of peak fraction cutting. Nevertheless, with regard to autonomous operation and batch to continuous processing modes, an advanced process control strategy is needed to identify and correct shifts from the optimal operation point automatically. Previous studies have already presented solutions for batch-to-batch variance and process control options with the aid of rigorous physico-chemical process modeling. These models can be implemented as distinct digital twins as well as statistical process operation data analyzers. In order to utilize such models for advanced process control (APC), the model parameters have to be updated with the aid of inline Process Analytical Technology (PAT) data to describe the actual operational status. This updating process also includes any operational change phenomena that occur, and its relation to their physico-chemical root cause. Typical phenomena are fluid dynamic changes due to packing breakage, channelling or compression as well as mass transfer and phase equilibrium-related separation performance decrease due to adsorbent aging or feed and buffer composition changes. In order to track these changes, an Artificial Neural Network (ANN) is trained in this work. The ANN training is in this first step, based on the simulation results of a distinct and previously experimentally validated process model. The model is implemented in the open source tool CasADi for Python. This allows the implementation of interfaces to process control systems, among others, with relatively low effort. Therefore, PAT signals can easily be incorporated for sufficient adjustment of the process model for appropriate process control. Further steps would be the implementation of optimization routines based on PAT and ANN predictions to derive optimal operation points with the model