Maximum intensity projection of cranial computed tomography data for dental identification

Dental radiographs play the major role in the identification of victims in mass casualties besides DNA. Under circumstances such as those caused by the recent tsunami in Asia, it is nearly impossible to document the entire dentition using conventional x-rays as it would be too time consuming. Multislice computed tomography can be used to scan the dentition of a deceased within minutes, and the postprocessing software allows visualization of the data adapted to every possible antemortem x-ray for identification. We introduce the maximum intensity projection of cranial computed tomography data for the purpose of dental identification exemplarily in a case of a burned corpse. As transportable CT scanners already exist, these could be used to support the disaster victim identification teams in the field.

Absence of histamine-induced nitric oxide release in the human radial artery: implications for vasospasm of coronary artery bypass vessels

Radial artery (RA) bypass grafts can develop severe vasospasm. As histamine is known to induce vasospasm, its effect on RA was assessed compared with the classic bypass vessels internal mammary artery (MA) and saphenous vein (SV). The vessels were examined in organ chambers for isometric tension recording. Histamine induced contractions on baseline; the sensitivity was higher in RA and SV than MA. After precontraction with norepinephrine, histamine did not evoke relaxations of RA but induced relaxations of MA and less of SV at lower concentrations; it induced contractions at higher concentrations, reaching similar levels in all three vessels. Indomethacin did not affect the response of MA and RA but potentiated relaxations and reduced contractions of SV. Endothelium removal, N(omega)-nitro-L-arginine methyl ester (L-NAME), or the H2-receptor blocker cimetidine did not affect the response of RA, but inhibited relaxations and enhanced contractions in MA and inhibited relaxations in SV; in the latter, only L-NAME enhanced contractions. Real-time PCR detected much lower expression of endothelial H2-receptor in RA than MA or SV. Western blots revealed similar endothelial nitric oxide (NO) synthase expression in all three vessels. Relaxations to acetylcholine were identical in RA and MA. Thus histamine releases NO by activating the endothelial H2-receptor, the expression of which is much lower in RA than MA or SV. H2-receptor activation also releases prostaglandins in SV, partially antagonizing NO. The lack of histamine-induced NO production represents a possible mechanism of RA vasospasm.

The correlation of urethral resistance pressure with maximum urethral closure pressure and stress incontinence

OBJECTIVE: Aim of the study was to correlate urethral retro resistance pressure with the maximum urethral closure pressure (MUCP) and functional urethral length (FUL) in patients with urinary incontinence and healthy individuals. STUDY DESIGN: Two hundred and twenty patients with the complaint of urinary incontinence had a urodynamic examination including urethral pressure profiles and URP. Additionally, 15 healthy individuals without the complaint of any incontinence had their URP and urethral pressure profiles measured. The correlation of MUCP, FUL and URP were calculated using Graph Pad Instat 4.0 for windows. RESULTS: URP correlates well with the diagnosis of urodynamic stress incontinence. Correlation coefficient between URP and MUCP is 0.9262. Healthy individuals have significantly higher values for URP and MUCP. CONCLUSION: URP is a valuable less invasive test than conventional urethral function tests for the diagnosis of urodynamic incontinence with an excellent correlation of MUCP and URP.

Effect of voluntary exercise on number and volume of cardiomyocytes and their mitochondria in the mouse left ventricle

Voluntary exercise (VE) has a beneficial influence on the heart and mean lifespan. The present study evaluates structural adaptations of cardiomyocytes and their mitochondria due to VE by new, unbiased stereological methods. Female, 7-9-week-old mice were randomly assigned to a control (CG, n = 7) or VE group (EG, n = 7). EG animals were housed in cages with free access to a running wheel and had a mean running distance of 6.7 (1.8) km per day. After 4 weeks, the hearts of all mice were processed for light and electron microscopy. We estimated the number and volume of cardiomyocytes by the disector method and the number and volume of mitochondria by estimation of the Euler number. In comparison to CG, VE did not have an effect on the myocardial volume of the left ventricle (CG: 93 (10), EG: 103 (17) (mm(3))), the number of cardiomyocytes (CG: 2.81 (0.27), EG: 2.82 (0.43) (x10(6))) and their number-weighted mean volume. However, the composition of the cardiomyocytes changed due to VE. The total volume of mitochondria (CG: 21.8 (4.9), EG: 32.2 (4.3) (mm(3)), P < 0.01) and the total number (CG: 3.76 (0.44), EG: 7.02 (1.13) (x10(10)), P < 0.001) were significantly higher in EG than in CG. The mean number-weighted mitochondrial volume was smaller in EG than in CG (P < 0.05). In summary, VE does not alter ventricular volume nor cardiomyocyte volume or number but the oxidative capacity of cardiomyocytes by an increased mitochondrial number and total volume in the left ventricle. These structural changes may participate in the beneficial effects of VE.

Mechanisms contributing to the deep chlorophyll maximum in Lake Superior

The seasonal appearance of a deep chlorophyll maximum (DCM) in Lake Superior is a striking phenomenon that is widely observed; however its mechanisms of formation and maintenance are not well understood. As this phenomenon may be the reflection of an ecological driver, or a driver itself, a lack of understanding its driving forces limits the ability to accurately predict and manage changes in this ecosystem. Key mechanisms generally associated with DCM dynamics (i.e. ecological, physiological and physical phenomena) are examined individually and in concert to establish their role. First the prevailing paradigm, “the DCM is a great place to live”, is analyzed through an integration of the results of laboratory experiments and field measurements. The analysis indicates that growth at this depth is severely restricted and thus not able to explain the full magnitude of this phenomenon. Additional contributing mechanisms like photoadaptation, settling and grazing are reviewed with a one-dimensional mathematical model of chlorophyll and particulate organic carbon. Settling has the strongest impact on the formation and maintenance of the DCM, transporting biomass to the metalimnion and resulting in the accumulation of algae, i.e. a peak in the particulate organic carbon profile. Subsequently, shade adaptation becomes manifest as a chlorophyll maximum deeper in the water column where light conditions particularly favor the process. Shade adaptation mediates the magnitude, shape and vertical position of the chlorophyll peak. Growth at DCM depth shows only a marginal contribution, while grazing has an adverse effect on the extent of the DCM. The observed separation of the carbon biomass and chlorophyll maximum should caution scientists to equate the DCM with a large nutrient pool that is available to higher trophic levels. The ecological significance of the DCM should not be separated from the underlying carbon dynamics. When evaluated in its entirety, the DCM becomes the projected image of a structure that remains elusive to measure but represents the foundation of all higher trophic levels. These results also offer guidance in examine ecosystem perturbations such as climate change. For example, warming would be expected to prolong the period of thermal stratification, extending the late summer period of suboptimal (phosphorus-limited) growth and attendant transport of phytoplankton to the metalimnion. This reduction in epilimnetic algal production would decrease the supply of algae to the metalimnion, possibly reducing the supply of prey to the grazer community. This work demonstrates the value of modeling to challenge and advance our understanding of ecosystem dynamics, steps vital to reliable testing of management alternatives.

Subject-ventilator synchrony during neural versus pneumatically triggered non-invasive helmet ventilation

OBJECTIVE: Patient-ventilator synchrony during non-invasive pressure support ventilation with the helmet device is often compromised when conventional pneumatic triggering and cycling-off were used. A possible solution to this shortcoming is to replace the pneumatic triggering with neural triggering and cycling-off-using the diaphragm electrical activity (EA(di)). This signal is insensitive to leaks and to the compliance of the ventilator circuit. DESIGN: Randomized, single-blinded, experimental study. SETTING: University Hospital. PARTICIPANTS AND SUBJECTS: Seven healthy human volunteers. INTERVENTIONS: Pneumatic triggering and cycling-off were compared to neural triggering and cycling-off during NIV delivered with the helmet. MEASUREMENTS AND RESULTS: Triggering and cycling-off delays, wasted efforts, and breathing comfort were determined during restricted breathing efforts (<20% of voluntary maximum EA(di)) with various combinations of pressure support (PSV) (5, 10, 20 cm H(2)O) and respiratory rates (10, 20, 30 breath/min). During pneumatic triggering and cycling-off, the subject-ventilator synchrony was progressively more impaired with increasing respiratory rate and levels of PSV (p < 0.001). During neural triggering and cycling-off, effect of increasing respiratory rate and levels of PSV on subject-ventilator synchrony was minimal. Breathing comfort was higher during neural triggering than during pneumatic triggering (p < 0.001). CONCLUSIONS: The present study demonstrates in healthy subjects that subject-ventilator synchrony, trigger effort, and breathing comfort with a helmet interface are considerably less impaired during increasing levels of PSV and respiratory rates with neural triggering and cycling-off, compared to conventional pneumatic triggering and cycling-off.

Maximum principle preserving high order schemes for convection-dominated diffusion equations

The maximum principle is an important property of solutions to PDE. Correspondingly, it's of great interest for people to design a high order numerical scheme solving PDE with this property maintained. In this thesis, our particular interest is solving convection-dominated diffusion equation. We first review a nonconventional maximum principle preserving(MPP) high order finite volume(FV) WENO scheme, and then propose a new parametrized MPP high order finite difference(FD) WENO framework, which is generalized from the one solving hyperbolic conservation laws. A formal analysis is presented to show that a third order finite difference scheme with this parametrized MPP flux limiters maintains the third order accuracy without extra CFL constraint when the low order monotone flux is chosen appropriately. Numerical tests in both one and two dimensional cases are performed on the simulation of the incompressible Navier-Stokes equations in vorticity stream-function formulation and several other problems to show the effectiveness of the proposed method.