Peculiarity of hybrid entrepreneurs – revisiting Lazear’s theory of entrepreneurship

The aim of this study is to explore and elaborate the concept of hybrid entrepreneurship, i.e., a simultaneous mix of self-employment (entrepreneurship) and salary employment. Lazear’s theory of entrepreneurship is assessed in terms whether it can explain the phenomenon of being a hybrid entrepreneur. The hypothesis is that the probability of linking a salary job with one’s own business increases with the variety and level of education gained, the broadness of professional and management experience but also the level of entrepreneurial self-efficacy. The hypotheses are tested with multivariate logistic regression, using survey data gathered from 1600 entrepreneurs. In light of the results, Lazear’s theory cannot be unambiguously extended to the case of hybrid entrepreneurs. Although the probability of being a hybrid entrepreneur increases with broader professional and managerial experience, at the same time it diminishes as the level and diversity of education increase. The results suggest that hybrid entrepreneurs are an importantly discrete population and therefore need to be treated separately. The theoretical and practical implications of the results are discussed

Rola doszklistkowych steroidów we współczesnym leczeniu cukrzycowego obrzęku plamki

Powikłania cukrzycy są jednym z najczęstszych i najpoważniejszych problemów we współczesnej okulistyce. W pracy przedstawiono dane epidemiologiczne i zasady leczenia retnopatii cukrzycowej i cukrzycowego obrzęku plamki. Szczególną uwagę zwrócono na rolę iniekcji doszklistkowych, w tym steroidów, które w niektórych przypadkach mogą być alternatywą dla inhibitorów naczyniowo-śrdódbłonkowego czynnika wzrostu (anty-VEGF). Zdaniem grupy ekspertów konieczne jest stworzenie programu lekowego obejmującego leczenie cukrzycowego obrzęku plamki, który istotnie poprawi dostęp do nowoczesnej terapii dużej grupie chorych. W programie lekowym lekiem pierwszego rzutu powinien być anty-VEGF z możliwością zmiany na doszklistkowy implant deksametazonu, w przypadku braku odpowiedzi na leczenie lub istnienia przeciwskazań do terapii anty-VEGF. Należy stworzyć precyzyjne kryteria kwalifikacji do programu, zdefiniować brak odpowiedzi na leczenie oraz określić wskazania do zmiany leku

Randomized, Controlled Trial of Therapy Interruption in Chronic HIV-1 Infection

BACKGROUND: Approaches to limiting exposure to antiretroviral therapy (ART) drugs are an active area of HIV therapy research. Here we present longitudinal follow-up of a randomized, open-label, single-center study of the immune, viral, and safety outcomes of structured therapy interruptions (TIs) in patients with chronically suppressed HIV-1 infection as compared to equal follow-up of patients on continuous therapy and including a final therapy interruption in both arms. METHODS AND FINDINGS: Forty-two chronically HIV-infected patients on suppressive ART with CD4 counts higher than 400 were randomized 1:1 to either (1) three successive fixed TIs of 2, 4, and 6 wk, with intervening resumption of therapy with resuppression for 4 wk before subsequent interruption, or (2) 40 wk of continuous therapy, with a final open-ended TI in both treatment groups. Main outcome was analysis of the time to viral rebound (>5,000 copies/ml) during the open-ended TI. Secondary outcomes included study-defined safety criteria, viral resistance, therapy failure, and retention of immune reconstitution. There was no difference between the groups in time to viral rebound during the open-ended TI (continuous therapy/single TI, median [interquartile range] = 4 [1–8] wk, n = 21; repeated TI, median [interquartile range] = 5 [4–8] wk, n = 21; p = 0.36). No differences in study-related adverse events, viral set point at 12 or 20 wk of open-ended interruption, viral resistance or therapy failure, retention of CD4 T cell numbers on ART, or retention of lymphoproliferative recall antigen responses were noted between groups. Importantly, resistance detected shortly after initial viremia following the open-ended TI did not result in a lack of resuppression to less than 50 copies/ml after reinitiation of the same drug regimen. CONCLUSION: Cycles of 2- to 6-wk time-fixed TIs in patients with suppressed HIV infection failed to confer a clinically significant benefit with regard to viral suppression off ART. Also, secondary analysis showed no difference between the two strategies in terms of safety, retention of immune reconstitution, and clinical therapy failure. Based on these findings, we suggest that further clinical research on the long-term consequences of TI strategies to decrease drug exposure is warranted

Biomechanical testing of trachea in a multidirectional load state

Uszkodzenia tchawicy spowodowane wprowadzeniem rur umożliwiających przywrócenie wentylacji płuc. Identyfikacja parametrów mechanicznych jest konieczna w celu rozpoznania patomechanizmu zmian w tkance, związanych z nieprawidłową przebudową. Uzyskane rezultaty badań mechanicznych pozwoliły na opracowanie modelu matematycznego tchawicy w warunkach wielokierunkowego obciążenia. Umożliwi to przewidywanie nadmiernych lokalnych zaburzeń pól odkształceń i naprężeń tchawicy, występujących podczas wprowadzenia rurki intubacyjnej, które do tej pory nie zostały jeszcze dokładnie zbadane.Tracheal injury caused by the introduction of tubes to restore lung ventilation. Identification of mechanical parameters is necessary in order to identify changes in the pathomechanism of tissue associated with abnormal remodeling. The results of mechanical tests allowed us to develop a mathematical model of the trachea in a multidirectional load conditions. This will allow prediction of excessive local disturbances of the fields of strain and stress in the trachea wall occurring during the insertion of the tracheal tube, which so far have not yet been thoroughly investigated

Material characteristic of an innovative stent for the treatment of urethral stenosis

The appropriate development and customisation of the stent to the urethral tissues requires the determination of many factors such as strength and degradation. Given the distinctive conditions of urethral tissues, it is important that the design of the stent be properly developed. The selection of a stent material requires knowing its material characteristics and verifying that they are suitable for the future implantation site. In the present study, the development of a polydioxanone (PDO)-based stent was undertaken. The PDO material was fabricated using an additive technique – 3D printing. Then, in vitro tests were performed to determine the degradation time of the material under conditions simulating an aggressive urinary environment. The changes in the parameters of mechanical properties before and after the degradation period were determined, and the changes in the structure of the material before and after degradation were observed. Numerical analysis was performed for the proposed stent design. The results showed that PDO has good mechanical properties, but its degradation time is too short to be used in a urethral stent. Among the innovations of the studies conducted are bending strength tests, which is not a frequently considered aspect so far

Evaluation of Selected Properties of Sodium Alginate-Based Hydrogel Material—Mechanical Strength, μDIC Analysis and Degradation

The search for ideal solutions for the treatment of urethral stenosis continues. This includes developing the material, design, while maintaining its optimal and desired properties. This paper presents the results of the research conducted on sodium alginate-based hydrogel material (AHM), which may be used as a material for stents dedicated to the treatment of pathologies occurring in the genitourinary system. In order to determine the selected parameters of the AHM samples, strength and degradation tests, as well as analysis of the micro changes occurring on the surface of the material using a digital image correlation (µDIC) system, were performed. This study shows that the material possessed good mechanical strength parameters, the knowledge of which is particularly important from the point of view of the stent-tissue interaction. The degradation analysis performed showed that the AHM samples degrade in an artificial urine environment, and that the degradation time mainly depends on the chemical composition of the material. The novel µDIC method performed allowed us to characterize the homogeneity of the material structure depending on the cross-linking agent used