Tension-Compression Loading with Chemical Stimulation Results in Additive Increases to Functional Properties of Anatomic Meniscal Constructs

Objective: This study aimed to improve the functional properties of anatomically-shaped meniscus constructs through simultaneous tension and compression mechanical stimulation in conjunction with chemical stimulation. Methods: Scaffoldless meniscal constructs were subjected to simultaneous tension and compressive stimulation and chemical stimulation. The temporal aspect of mechanical loadingwas studied by employing two separate five day stimulation periods. Chemical stimulation consisted of the application of a catabolic GAG-depleting enzyme, chondroitinase ABC (C-ABC), and an anabolic growth factor, TGF-b1. Mechanical and chemical stimulation combinations were studied through a full-factorial experimental design and assessed for histological, biochemical, and biomechanical properties following 4 wks of culture. Results: Mechanical loading applied from days 10–14 resulted in significant increases in compressive, tensile, and biochemical properties of meniscal constructs. When mechanical and chemical stimuliwere combined significant additive increases in collagen per wet weight (4-fold), compressive instantaneous (3-fold) and relaxation (2-fold) moduli, and tensile moduli in the circumferential (4-fold) and radial (6-fold) directions were obtained. Conclusions: This study demonstrates that a stimulation regimen of simultaneous tension and compression mechanical stimulation, C-ABC, and TGF-b1 is able to create anatomic meniscus constructs replicating the compressive mechanica

Supernovae from massive stars

Massive stars, by which we mean those stars exploding as core collapse supernovae, play a pivotal role in the evolution of the Universe. Therefore, the understanding of their evolution and explosion is fundamental in many branches of physics and astrophysics, among which, galaxy evolution, nucleosynthesis, supernovae, neutron stars and pulsars, black holes, neutrinos and gravitational waves. In this chapter, the author presents an overview of the presupernova evolution of stars in the range between 13 and 120 $\rm M_\odot$, with initial metallicities between [Fe/H]=-3 and [Fe/H]=0 and initial rotation velocities $\rm v=0,~150,~300~km/s$. Emphasis is placed upon those evolutionary properties that determine the final fate of the star with special attention to the interplay among mass loss, mixing and rotation. A general picture of the evolution and outcome of a generation of massive stars, as a function of the initial mass, metallicity and rotation velocity, is finally outlined.Comment: Author version of a chapter for 'Handbook of Supernovae,' edited by A. Alsabti and P. Murdin, Springer. 59 pages, 27 figure

Anesthesia advanced circulatory life support

The constellation of advanced cardiac life support (ACLS) events, such as gas embolism, local anesthetic overdose, and spinal bradycardia, in the perioperative setting differs from events in the pre-hospital arena. As a result, modification of traditional ACLS protocols allows for more specific etiology-based resuscitation. Perioperative arrests are both uncommon and heterogeneous and have not been described or studied to the same extent as cardiac arrest in the community. These crises are usually witnessed, frequently anticipated, and involve a rescuer physician with knowledge of the patient's comorbidities and coexisting anesthetic or surgically related pathophysiology. When the health care provider identifies the probable cause of arrest, the practitioner has the ability to initiate medical management rapidly. Recommendations for management must be predicated on expert opinion and physiological understanding rather than on the standards currently being used in the generation of ACLS protocols in the community. Adapting ACLS algorithms and considering the differential diagnoses of these perioperative events may prevent cardiac arrest

Vampires in the village Žrnovo on the island of Korčula: following an archival document from the 18th century

Središnja tema rada usmjerena je na raščlambu spisa pohranjenog u Državnom arhivu u Mlecima (fond: Capi del Consiglio de’ Dieci: Lettere di Rettori e di altre cariche) koji se odnosi na događaj iz 1748. godine u korčulanskom selu Žrnovo, kada su mještani – vjerujući da su se pojavili vampiri – oskvrnuli nekoliko mjesnih grobova. U radu se podrobno iznose osnovni podaci iz spisa te rečeni događaj analizira u širem društvenom kontekstu i prate se lokalna vjerovanja.The main interest of this essay is the analysis of the document from the State Archive in Venice (file: Capi del Consiglio de’ Dieci: Lettere di Rettori e di altre cariche) which is connected with the episode from 1748 when the inhabitants of the village Žrnove on the island of Korčula in Croatia opened tombs on the local cemetery in the fear of the vampires treating. This essay try to show some social circumstances connected with this event as well as a local vernacular tradition concerning superstitions

A new Urca process

In the course of a general study of electron capture and β-decay rates on fp shell nuclei which are abundant after core silicon burning in massive stars, we have found that the Fuller, Fowler and Newman β-decay rate are much stronger than generally has been realized. In fact, they can balance the capture rates during the conditions which are prevalent after core silicon burning, resulting in a new Urca process. The strength of the β-decay rates is a result of thermal population of the Gamow-Teller back resonance in the parent nucleus and the behavior of β-decay and electron capture Q-values for ensembles of nuclei in nuclear statistical equilibrium. All β-decay rate tabulations prior to Fuller, Fowler, and Newman neglected the contribution of back resonances and thus drastically underestimated the overall rate. We use a simple analytic model to explain this balancing. The full rates are coupled to a nuclear statictical equilibrium code to demonstrate the strength of the decays. One zone models are used to examine, in a self-consistent fashion, how these rates could affect the presupernova evolution of the iron core and hence the core collapse problem

A new Urca process

In the course of a general study of electron capture and β-decay rates on fp shell nuclei which are abundant after core silicon burning in massive stars, we have found that the Fuller, Fowler and Newman β-decay rate are much stronger than generally has been realized. In fact, they can balance the capture rates during the conditions which are prevalent after core silicon burning, resulting in a new Urca process. The strength of the β-decay rates is a result of thermal population of the Gamow-Teller back resonance in the parent nucleus and the behavior of β-decay and electron capture Q-values for ensembles of nuclei in nuclear statistical equilibrium. All β-decay rate tabulations prior to Fuller, Fowler, and Newman neglected the contribution of back resonances and thus drastically underestimated the overall rate. We use a simple analytic model to explain this balancing. The full rates are coupled to a nuclear statictical equilibrium code to demonstrate the strength of the decays. One zone models are used to examine, in a self-consistent fashion, how these rates could affect the presupernova evolution of the iron core and hence the core collapse problem

The QCD phase transition and supernova core collapse

We examine the implications for stellar core collapse of a phase transition occurring at densities of a few times nuclear matter density. We use a schematic equation of state motivated by the Skyrme model low-energy approximation to QCD, which contains a phase transition corresponding to the conversion of bulk nuclear matter to a chirally symmetric quark-gluon phase. We analyze the stability of the core against gravitational collapse with respect to the amount of gravitational binding energy released and the kinematic energy of the shock. We show that a first-order phase transition actually gives rise to two shocks which quickly coalesce. More importantly, we show that there are significant differences in the evolution of cores with or without first- or second-order phase transitions which may eventually lead to observational signatures in the neutrino signal