A Simple Mathematical-Model and Alternative Paradigm for Certain Chemotherapeutic Regimens

A simplified two-compartment model for cell-specific chemotherapy is analysed by reformulating the governing system of differential equations as a Schrodinger equation in time. With the choice of an exponentially decaying function representing the effects of chemotherapy on cycling tumor cells, the potential function V(t) is a Morse-type potential, well known in the quantum mechanical literature; and the solutions are obtainable in terms of confluent hypergeometric functions (or the related Whittaker functions). Because the chemotherapy is administered periodically, the potential V(t) is periodic also, and use is made of existing theory (Floquet theory) as applied to scattering by periodic potentials in the quantum theory of solids. Corresponding to the existence \u27\u27forbidden energy bands\u27\u27 in that context, it appears that there are \u27\u27forbidden\u27\u27 or inappropriate chemotherapeutic regimens also, in the sense that for some combinations of period, dosage, and cell parameters, no real solutions exist for the system of equations describing the time evolution of cancer cells in each compartment. A similar, but less complex phenomenon may occur for simpler mathematical representations of the regimen. The purpose of this paper is to identify the existence of this phenomenon, at least insofar as this model is concerned, and to examine the implications for clinical activities. This new paradigm, if structually stable (in the sense of the phenomenon occurring in more realistic models of chemotherapy) may be of considerable significance in identifying those regimens which are appropriate for effective chemotherapy, by providing a rational basis for such decisions, rather than by \u27\u27trial and error\u27\u27 (see the statement by Skipper [1] at the conclusion of this paper)

Percutaneous Management of a Long Saphenous Vein Graft Aneurysm: A Case Report and Review of Literature

Aneurysms of saphenous vein grafts are rare but can result in complications such as myocardial infarction or death. Percutaneous treatment has included a variety of approaches, including covered stents. Long aneurysms in saphenous vein grafts pose an additional challenge due to the lack of coronary covered stents with sufficient length. We present successful treatment of a long saphenous vein graft aneurysm with use of peripheral covered stents over two coronary guidewires, a 55-centimeter 8-French sheath and no guide catheter

Measurement of the mass of the τ lepton

The mass of the τ lepton has been measured at the Beijing Electron-Positron Collider using the Beijing Spectrometer. A search near threshold for e^+e^-→τ^+τ^- was performed. Candidate events were identified by requiring that one τ decay via τ→eνν¯, and the other via τ→μνν¯. The mass value, obtained from a fit to the energy dependence of the τ^+τ^- cross section, is m_τ=1776.9_(-0.5)^(+0.4)±0.2 MeV

Long-time Behavior of a Two-layer Model of Baroclinic Quasi-geostrophic Turbulence

We study a viscous two-layer quasi-geostrophic beta-plane model that is forced by imposition of a spatially uniform vertical shear in the eastward (zonal) component of the layer flows, or equivalently a spatially uniform north-south temperature gradient. We prove that the model is linearly unstable, but that non-linear solutions are bounded in time by a bound which is independent of the initial data and is determined only by the physical parameters of the model. We further prove, using arguments first presented in the study of the Kuramoto-Sivashinsky equation, the existence of an absorbing ball in appropriate function spaces, and in fact the existence of a compact finite-dimensional attractor, and provide upper bounds for the fractal and Hausdorff dimensions of the attractor. Finally, we show the existence of an inertial manifold for the dynamical system generated by the model's solution operator. Our results provide rigorous justification for observations made by Panetta based on long-time numerical integrations of the model equations

3D enamel thickness in Neandertal and modern human permanent canines

Enamel thickness figures prominently in studies of human evolution, particularly for taxonomy, phylogeny, and paleodietary reconstruction. Attention has focused on molar teeth, through the use of advanced imaging technologies and novel protocols. Despite the important results achieved thus far, further work is needed to investigate all tooth classes. We apply a recent approach developed for anterior teeth to investigate the 3D enamel thickness of Neandertal and modern human (MH) canines. In terms of crown size, the values obtained for both upper and lower unworn/slightly worn canines are significantly greater in Neandertals than in Upper Paleolithic and recent MH. The 3D relative enamel thickness (RET) is significantly lower in Neandertals than in MH. Moreover, differences in 3D RET values between the two groups appear to decrease in worn canines beginning from wear stage 3, suggesting that both the pattern and the stage of wear may have important effects on the 3D RET value. Nevertheless, the 3D average enamel thickness (AET) does not differ between the two groups. In both groups, 3D AET and 3D RET indices are greater in upper canines than in lower canines, and overall the enamel is thicker on the occlusal half of the labial aspect of the crown, particularly in MH. By contrast, the few early modern humans investigated show the highest volumes of enamel while for all other components of 3D enamel, thickness this group holds an intermediate position between Neandertals and recent MH. Overall, our study supports the general findings that Neandertals have relatively thinner enamel than MH (as also observed in molars), indicating that unworn/slightly worn canines can be successfully used to discriminate between the two groups. Further studies, however, are needed to understand whether these differences are functionally related or are the result of pleiotropic or genetic drift effects

Dispersive stabilization of the inverse cascade for the Kolmogorov flow

It is shown by perturbation techniques and numerical simulations that the inverse cascade of kink-antikink annihilations, characteristic of the Kolmogorov flow in the slightly supercritical Reynolds number regime, is halted by the dispersive action of Rossby waves in the beta-plane approximation. For beta tending to zero, the largest excited scale is proportional to the logarithm of one over beta and differs strongly from what is predicted by standard dimensional phenomenology which ignores depletion of nonlinearity.Comment: 4 pages, LATEX, 3 figures. v3: revised version with minor correction

An Online Platform for Underwater Image Quality Evaluation

With the miniaturisation of underwater cameras, the volume of available underwater images has been considerably increasing. However, underwater images are degraded by the absorption and scattering of light in water. Image processing methods exist that aim to compensate for these degradations, but there are no standard quality evaluation measures or testing datasets for a systematic empirical comparison. For this reason, we propose PUIQE, an online platform for underwater image quality evaluation, which is inspired by other computer vision areas whose progress has been accelerated by evaluation platforms. PUIQE supports the comparison of methods through standard datasets and objective evaluation measures: quality scores for images uploaded on the platform are automatically computed and published in a leaderboard, which enables the ranking of methods. We hope that PUIQE will stimulate and facilitate the development of underwater image processing algorithms to improve underwater images

Phenotypic Spectrum of Seizure Disorders in MBD5-Associated Neurodevelopmental Disorder

OBJECTIVE: To describe the phenotypic spectrum in patients with MBD5-associated neurodevelopmental disorder (MAND) and seizures; features of MAND include intellectual disability, epilepsy, psychiatric features of aggression and hyperactivity, and dysmorphic features including short stature and microcephaly, sleep disturbance, and ataxia. METHODS: We performed phenotyping on patients with MBD5 deletions, duplications, or point mutations and a history of seizures. RESULTS: Twenty-three patients with MAND and seizures were included. Median seizure onset age was 2.9 years (range 3 days–13 years). The most common seizure type was generalized tonic-clonic; focal, atypical absence, tonic, drop attacks, and myoclonic seizures occurred frequently. Seven children had convulsive status epilepticus and 3 nonconvulsive status epilepticus. Fever, viral illnesses, and hot weather provoked seizures. EEG studies in 17/21 patients were abnormal, typically showing slow generalized spike-wave and background slowing. Nine had drug-resistant epilepsy, although 3 eventually became seizure-free. All but one had moderate-to-severe developmental impairment. Epilepsy syndromes included Lennox-Gastaut syndrome, myoclonic-atonic epilepsy, and infantile spasms syndrome. Behavioral problems in 20/23 included aggression, self-injurious behavior, and sleep disturbance. CONCLUSION: MBD5 disruption may be associated with severe early childhood-onset developmental and epileptic encephalopathy. Because neuropsychiatric dysfunction is common and severe, it should be an important focus of clinical management

The Coupled Aerosol and Tracer Transport model to the Brazilian developments on the Regional Atmospheric Modeling System (CATT-BRAMS) ? Part 1: Model description and evaluation

International audienceWe introduce the Coupled Aerosol and Tracer Transport model to the Brazilian developments on the Regional Atmospheric Modeling System (CATT-BRAMS). CATT-BRAMS is an on-line transport model fully consistent with the simulated atmospheric dynamics. Emission sources from biomass burning and urban-industrial-vehicular activities for trace gases and aerosol particles are obtained from several published datasets and remote sensing information. The tracer and aerosol mass concentration prognostic includes the effects of sub-grid scale turbulence in the planetary boundary layer, convective transport by shallow and deep moist convection, wet and dry deposition, and plume rise associated with vegetation fires in addition to the grid scale transport. The radiation parameterization takes into account the interaction between aerosol particles and short and long wave radiation. The atmospheric model BRAMS is based on the Regional Atmospheric Modeling System (RAMS), with several improvements associated with cumulus convection representation, soil moisture initialization and surface scheme tuned for the tropics, among others. In this paper the CATT-BRAMS model is used to simulate carbon monoxide and particulate material (PM2.5) surface fluxes and atmospheric transport during the 2002 LBA field campaigns, conducted during the transition from the dry to wet season in the southwest Amazon Basin. Model evaluation is addressed with comparisons between model results and near surface, radiosonde and airborne measurements performed during the field campaign, as well as remote sensing derived products. We show the matching of emissions strengths to observed carbon monoxide in the LBA campaign. A relatively good comparison to the MOPITT data, in spite of the fact that MOPITT a priori assumptions imply several difficulties, is also obtained

How Do Climate Change Experiments Alter Plot-Scale Climate?

To understand and forecast biological responses to climate change, scientists frequently use field experiments that alter temperature and precipitation. Climate manipulations can manifest in complex ways, however, challenging interpretations of biological responses. We reviewed publications to compile a database of daily plot-scale climate data from 15 active-warming experiments. We find that the common practices of analysing treatments as mean or categorical changes (e.g. warmed vs.unwarmed) masks important variation in treatment effects over space and time. Our synthesis showed that measured mean warming, in plots with the same target warming within a study, differed by up to 1.6 Celsius degrees (63% of target), on average, across six studies with blocked designs. Variation was high across sites and designs: for example, plots differed by 1.1Celsius degrees (47% of target) on average, for infrared studies with feedback control (n = 3) vs. by 2.2 Celsius degrees (80% of target) on average for infrared with constant wattage designs (n = 2). Warming treatments produce non-temperature effects as well, such as soil drying. The combination of these direct and indirect effects is complex and can have important biological consequences. With a case study of plant phenology across five experiments in our database, we show how accounting for drier soils with warming tripled the estimated sensitivity of budburst to temperature. We provide recommendations for future analyses, experimental design,and data sharing to improve our mechanistic understanding from climate change experiments, and thus their utility to accurately forecast species' responses