78 research outputs found
The concept and position of circumstantiality mitigation in clinical criminology approach
Determining the penalty for offenders with regard to circumstantiality mitigation, including valuable gains of criminal law and its best examples refers to "personalization of penalty ", which developments in this field are recognized throughout history and influenced by the teachings of the neoclassical school and Social defense movement among legislators and judicial authorities. This legal entity with available judicial and legislative tools gives judges the possibility to determine sentence commuted based on the criteria such as physical and emotional state, economic - social and familial conditions. On the other hand, it seems that the commutation entity has been redefined in discursive space of this approach through influence of clinical approaches that are based on the belief of offender corrigibility, on the field of criminal law and tackle with penalty and intimidation approaches. This paper examines the norms, rules and principles governing circumstantiality mitigation in the context of clinical criminology theory regardless of committed crime. The present study was theoretical and by using analytical - descriptive method has studied mitigating measures of penalty in clinical criminology regardless of the nature and type of committed crime.
The concept and position of circumstantiality mitigation in clinical criminology approach
Determining the penalty for offenders with regard to circumstantiality mitigation, including valuable gains of criminal law and its best examples refers to "personalization of penalty ", which developments in this field are recognized throughout history and influenced by the teachings of the neoclassical school and Social defense movement among legislators and judicial authorities. This legal entity with available judicial and legislative tools gives judges the possibility to determine sentence commuted based on the criteria such as physical and emotional state, economic - social and familial conditions. On the other hand, it seems that the commutation entity has been redefined in discursive space of this approach through influence of clinical approaches that are based on the belief of offender corrigibility, on the field of criminal law and tackle with penalty and intimidation approaches. This paper examines the norms, rules and principles governing circumstantiality mitigation in the context of clinical criminology theory regardless of committed crime. The present study was theoretical and by using analytical - descriptive method has studied mitigating measures of penalty in clinical criminology regardless of the nature and type of committed crime.
Generation and escape of local waves from the boundary of uncoupled cardiac tissue
We aim to understand the formation of abnormal waves of activity from
myocardial regions with diminished cell-to-cell coupling. In route to this
goal, we studied the behavior of a heterogeneous myocyte network in which a
sharp coupling gradient was placed under conditions of increasing network
automaticity. Experiments were conducted in monolayers of neonatal rat
cardiomyocytes using heptanol and isoproterenol as means of altering
cell-to-cell coupling and automaticity respectively. Experimental findings were
explained and expanded using a modified Beeler-Reuter numerical model. The data
suggests that the combination of a heterogeneous substrate, a gradient of
coupling and an increase in oscillatory activity of individual cells creates a
rich set of behaviors associated with self-generated spiral waves and ectopic
sources. Spiral waves feature a flattened shape and a pin-unpin drift type of
tip motion. These intercellular waves are action-potential based and can be
visualized with either voltage or calcium transient measurements. A source/load
mismatch on the interface between the boundary and well-coupled layers can lock
wavefronts emanating from both ectopic sources and rotating waves within the
inner layers of the coupling gradient. A numerical approach allowed us to
explore how: i) the spatial distribution of cells, ii) the amplitude and
dispersion of cell automaticity, iii) and the speed at which the coupling
gradient moves in space, affects wave behavior, including its escape into
well-coupled tissue.Comment: 28 pages, 10 figures, submitted to Biophysical Journa
Circle Method for Robust Estimation of Local Conduction Velocity High-Density Maps From Optical Mapping Data: Characterization of Radiofrequency Ablation Sites
Conduction velocity (CV) slowing is associated with atrial fibrillation (AF) and reentrant ventricular tachycardia (VT). Clinical electroanatomical mapping systems used to localize AF or VT sources as ablation targets remain limited by the number of measuring electrodes and signal processing methods to generate high-density local activation time (LAT) and CV maps of heterogeneous atrial or trabeculated ventricular endocardium. The morphology and amplitude of bipolar electrograms depend on the direction of propagating electrical wavefront, making identification of low-amplitude signal sources commonly associated with fibrotic area difficulty. In comparison, unipolar electrograms are not sensitive to wavefront direction, but measurements are susceptible to distal activity. This study proposes a method for local CV calculation from optical mapping measurements, termed the circle method (CM). The local CV is obtained as a weighted sum of CV values calculated along different chords spanning a circle of predefined radius centered at a CV measurement location. As a distinct maximum in LAT differences is along the chord normal to the propagating wavefront, the method is adaptive to the propagating wavefront direction changes, suitable for electrical conductivity characterization of heterogeneous myocardium. In numerical simulations, CM was validated characterizing modeled ablated areas as zones of distinct CV slowing. Experimentally, CM was used to characterize lesions created by radiofrequency ablation (RFA) on isolated hearts of rats, guinea pig, and explanted human hearts. To infer the depth of RFA-created lesions, excitation light bands of different penetration depths were used, and a beat-to-beat CV difference analysis was performed to identify CV alternans. Despite being limited to laboratory research, studies based on CM with optical mapping may lead to new translational insights into better-guided ablation therapies
Contraction-induced cluster formation in cardiac cell culture
Evolution of the spatial arrangement of cells in a primary culture of cardiac
tissue derived from newborn rats was studied experimentally over extended
period. It was found that cells attract each other spontaneously to form a
clustered structure over the timescale of several days. These clusters exhibit
spontaneous rhythmic contraction and have been confirmed to consist of cardiac
muscle cells. Addition of a contraction inhibitor (2,3-butanedione-2-monoxime)
to the culture medium resulted in the inhibition of both the spontaneous
contractions exhibited by the cells as well as the formation of clusters.
Furthermore, the formation of clusters is suppressed when high concentrations
of collagen are used for coating the substratum to which the cells adhere. From
these experimental observations, it was deduced that the cells are mechanically
stressed by the tension associated with repeated contractions and that this
results in the cells becoming compact and attracting each other, finally
resulting in the formation of clusters. This process can be interpreted as
modulation of a cellular network by the activity associated with contraction,
which could be employed to control cellular networks by modifying the dynamics
associated with the contractions in cardiac tissue culture.Comment: 12 pages, 12 figure
Implantation of Mouse Embryonic Stem Cell-Derived Cardiac Progenitor Cells Preserves Function of Infarcted Murine Hearts
Stem cell transplantation holds great promise for the treatment of myocardial infarction injury. We recently described the embryonic stem cell-derived cardiac progenitor cells (CPCs) capable of differentiating into cardiomyocytes, vascular endothelium, and smooth muscle. In this study, we hypothesized that transplanted CPCs will preserve function of the infarcted heart by participating in both muscle replacement and neovascularization. Differentiated CPCs formed functional electromechanical junctions with cardiomyocytes in vitro and conducted action potentials over cm-scale distances. When transplanted into infarcted mouse hearts, CPCs engrafted long-term in the infarct zone and surrounding myocardium without causing teratomas or arrhythmias. The grafted cells differentiated into cross-striated cardiomyocytes forming gap junctions with the host cells, while also contributing to neovascularization. Serial echocardiography and pressure-volume catheterization demonstrated attenuated ventricular dilatation and preserved left ventricular fractional shortening, systolic and diastolic function. Our results demonstrate that CPCs can engraft, differentiate, and preserve the functional output of the infarcted heart
Scroll-Wave Dynamics in Human Cardiac Tissue: Lessons from a Mathematical Model with Inhomogeneities and Fiber Architecture
Cardiac arrhythmias, such as ventricular tachycardia (VT) and ventricular fibrillation (VF), are among the leading causes of death in the industrialized world. These are associated with the formation of spiral and scroll waves of electrical activation in cardiac tissue; single spiral and scroll waves are believed to be associated with VT whereas their turbulent analogs are associated with VF. Thus, the study of these waves is an important biophysical problem. We present a systematic study of the combined effects of muscle-fiber rotation and inhomogeneities on scroll-wave dynamics in the TNNP (ten Tusscher Noble Noble Panfilov) model for human cardiac tissue. In particular, we use the three-dimensional TNNP model with fiber rotation and consider both conduction and ionic inhomogeneities. We find that, in addition to displaying a sensitive dependence on the positions, sizes, and types of inhomogeneities, scroll-wave dynamics also depends delicately upon the degree of fiber rotation. We find that the tendency of scroll waves to anchor to cylindrical conduction inhomogeneities increases with the radius of the inhomogeneity. Furthermore, the filament of the scroll wave can exhibit drift or meandering, transmural bending, twisting, and break-up. If the scroll-wave filament exhibits weak meandering, then there is a fine balance between the anchoring of this wave at the inhomogeneity and a disruption of wave-pinning by fiber rotation. If this filament displays strong meandering, then again the anchoring is suppressed by fiber rotation; also, the scroll wave can be eliminated from most of the layers only to be regenerated by a seed wave. Ionic inhomogeneities can also lead to an anchoring of the scroll wave; scroll waves can now enter the region inside an ionic inhomogeneity and can display a coexistence of spatiotemporal chaos and quasi-periodic behavior in different parts of the simulation domain. We discuss the experimental implications of our study
The role of senescence in the pathogenesis of atrial fibrillation: a target process for health improvement and drug development
Cardiovascular health and particulate vehicular emissions: a critical evaluation of the evidence
A major public health goal is to determine linkages between specific pollution sources and adverse health outcomes. This paper provides an integrative evaluation of the database examining effects of vehicular emissions, such as black carbon (BC), carbonaceous gasses, and ultrafine PM, on cardiovascular (CV) morbidity and mortality. Less than a decade ago, few epidemiological studies had examined effects of traffic emissions specifically on these health endpoints. In 2002, the first of many studies emerged finding significantly higher risks of CV morbidity and mortality for people living in close proximity to major roadways, vs. those living further away. Abundant epidemiological studies now link exposure to vehicular emissions, characterized in many different ways, with CV health endpoints such as cardiopulmonary and ischemic heart disease and circulatory-disease-associated mortality; incidence of coronary artery disease; acute myocardial infarction; survival after heart failure; emergency CV hospital admissions; and markers of atherosclerosis. We identify numerous in vitro, in vivo, and human panel studies elucidating mechanisms which could explain many of these cardiovascular morbidity and mortality associations. These include: oxidative stress, inflammation, lipoperoxidation and atherosclerosis, change in heart rate variability (HRV), arrhythmias, ST-segment depression, and changes in vascular function (such as brachial arterial caliber and blood pressure). Panel studies with accurate exposure information, examining effects of ambient components of vehicular emissions on susceptible human subjects, appear to confirm these mechanisms. Together, this body of evidence supports biological mechanisms which can explain the various CV epidemiological findings. Based upon these studies, the research base suggests that vehicular emissions are a major environmental cause of cardiovascular mortality and morbidity in the United States. As a means to reduce the public health consequences of such emissions, it may be desirable to promulgate a black carbon (BC) PM2.5 standard under the National Ambient Air Quality Standards, which would apply to both on and off-road diesels. Two specific critical research needs are identified. One is to continue research on health effects of vehicular emissions, gaseous as well as particulate. The second is to utilize identical or nearly identical research designs in studies using accurate exposure metrics to determine whether other major PM pollutant sources and types may also underlie the specific health effects found in this evaluation for vehicular emissions
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