Mechanics of Reversible Unzipping

We study the mechanics of a reversible decohesion (unzipping) of an elastic layer subjected to quasi-static end-point loading. At the micro level the system is simulated by an elastic chain of particles interacting with a rigid foundation through breakable springs. Such system can be viewed as prototypical for the description of a wide range of phenomena from peeling of polymeric tapes, to rolling of cells, working of gecko's fibrillar structures and denaturation of DNA. We construct a rigorous continuum limit of the discrete model which captures both stable and metastable configurations and present a detailed parametric study of the interplay between elastic and cohesive interactions. We show that the model reproduces the experimentally observed abrupt transition from an incremental evolution of the adhesion front to a sudden complete decohesion of a macroscopic segment of the adhesion layer. As the microscopic parameters vary the macroscopic response changes from quasi-ductile to quasi-brittle, with corresponding decrease in the size of the adhesion hysteresis. At the micro-scale this corresponds to a transition from a `localized' to a `diffuse' structure of the decohesion front (domain wall). We obtain an explicit expression for the critical debonding threshold in the limit when the internal length scales are much smaller than the size of the system. The achieved parametric control of the microscopic mechanism can be used in the design of new biological inspired adhesion devices and machines

Simple Parameters from Complete Blood Count Predict In-Hospital Mortality in COVID-19

The clinical course of Coronavirus Disease 2019 (COVID-19) is highly heterogenous, ranging from asymptomatic to fatal forms. The identification of clinical and laboratory predictors of poor prognosis may assist clinicians in monitoring strategies and therapeutic decisions

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology

Long-term femoral vein central venous access in cancer patients.

Subclavian percutaneous access with reservoir placement has been shown to be difficult or contraindicated in some patients. Of 465 cancer patients who required a port placement between January 1992 to January 1995, 41 (8.8%) had alternative percutaneous femoral access with a totally implantable port reservoir located in the abdomen because of the inaccessibility to subclavian or jugular veins and/or the presence of massive cutaneous metastases or severe radiodermitis in the upper part of the torso. Overall implant days was 9880, with an average of 241 days (range: 65-445). Ports were alternatively used for chemotherapy and nutritional purposes in 11 of 41 patients. Late morbidity causing the removal of the implanted ports was observed in two of 41 (4.9%) and 25 of 424 (5.9%) patients in the femoral and subclavian series, respectively (P = 0.86). The femoral percutaneous access for totally implantable port devices appears to be a safe alternative for cancer patients when subclavian and/or jugular vein catheterization and reservoir in the upper part of the torso is contraindicated

[Current status of the classification and clinical staging of primary and secondary tumors of the liver].

Over the past few decades there has been outstanding expansion in the surgical exeresis of primary and metastatic liver tumours and particularly hepatic metastases of colorectal carcinomas. With the advance in surgical technique it becomes increasingly necessary to codify the system for the classification and clinical staging of these conditions for the purposes of correct programming of treatment and assessment of the clinical results obtained. The most commonly used systems of classification and clinical staging are analysed, in particular the classifications proposed by the American Joint Committee on Cancer and D. Manfredi for primary liver tumours and those proposed by Gennari et al and Sugerbaker et al for hepatic metastases of colorectal carcinomas. The selection criteria adopted in each system are analysed as the basis for a more thorough discussion of the problem that is felt to be fundamental for the standardisation of classification and clinical staging systems in the future. Such standardisation is essential for the assessment of the value and limitations of liver surgery in cancer