Exact Relationships Research Articles

Toxic influence of organophosphate, carbamate, and organochlorine pesticides on cellular metabolism of lipids, proteins, and carbohydrates

Pesticides, including organophosphate (OP), organochlorine (OC), and carbamate (CB) compounds, are widely used in agricultural and indoor purposes. OP and CB act as acetyl cholinesterase (AChE) inhibitors that affect lots of organs such as peripheral and central nervous systems, muscles, liver, pancreas, and brain, whereas OC are neurotoxic involved in alteration of ion channels. There are several reports about metabolic disorders, hyperglycemia, and also oxidative stress in acute and chronic exposures to pesticides that are linked with diabetes and other metabolic disorders. In this respect, there are several in vitro and in vivo but few clinical studies about mechanism underlying these effects. Bibliographic databases were searched for the years 1963–2010 and resulted in 1652 articles. After elimination of duplicates or irrelevant papers, 204 papers were included and reviewed. Results indicated that OP and CB impair the enzymatic pathways involved in metabolism of carbohydrates, fats and protein within cytoplasm, mitochondria, and proxisomes. It is believed that OP and CB show this effect through inhibition of AChE or affecting target organs directly. OC mostly affect lipid metabolism in the adipose tissues and change glucose pathway in other cells. As a shared mechanism, all OP, CB and OC induce cellular oxidative stress via affecting mitochondrial function and therefore disrupt neuronal and hormonal status of the body. Establishing proper epidemiological studies to explore exact relationships between exposure levels to these pesticides and rate of resulted metabolic disorders in human will be helpful.

Universal four-component Fermi gas in one dimension

A four-component Fermi gas in one dimension with a short-range four-body interaction is shown to exhibit a one-dimensional analog of the BCS-BEC crossover. Its low-energy physics is governed by a Tomonaga-Luttinger liquid with three spin gaps. The spin gaps are exponentially small in the weak coupling (BCS) limit where they arise from the charge-density-wave instability, and become large in the strong coupling (BEC) limit because of the formation of tightly-bound tetramers. We investigate the ground-state energy, the sound velocity, and the gap spectrum in the BCS-BEC crossover and discuss exact relationships valid in our system. We also show that a one-dimensional analog of the Efimov effect occurs for five bosons while it is absent for fermions. Our work opens up a very rich new field of universal few-body and many-body physics in one dimension.

A new fossil sirenian (Mammalia, Dugonginae) from the Miocene of India

Kutchisiren cylindrica, n. gen. n. sp., is a dugongine sirenian represented by a single skull with mandible from the Lower Miocene (Aquitanian or Burdigalian) Khari Nadi Formation in the district of Kutch (= Kachchh), Gujarat State, western India. It is characterized by a braincase of nearly cylindrical form, a strong rostral deflection of about 78°, and a large upper incisor tusk with a lozenge-shaped cross section. It evidently coexisted with at least two other dugongine taxa: Bharatisiren kachchhensis and Domningia sodhae. These three forms differed in rostral deflection, body size, and other details of skull and tusk morphology that apparently enabled them to partition the available marine seagrass resources. Their exact phylogenetic relationships, however, remain unresolved for now.

Role of dispersion on phononic thermal boundary conductance

The diffuse mismatch model (DMM) is one of the most widely implemented models for predicting thermal boundary conductance at interfaces where phonons dominate interfacial thermal transport. In the original presentation of the DMM, the materials comprising the interface were described as Debye solids. Such a treatment, while accurate in the low temperature regime for which the model was originally intended, is less accurate at higher temperatures. Here, the DMM is reformulated such that, in place of Debye dispersion, the materials on either side of the interface are described by an isotropic dispersion obtained from exact phonon dispersion diagrams in the [100] crystallographic direction. This reformulated model is applied to three interfaces of interest: Cr–Si, Cu–Ge, and Ge–Si. It is found that Debye dispersion leads to substantially higher predictions of thermal boundary conductance. Additionally, it is shown that optical phonons play a significant role in interfacial thermal transport, a notion not previously explored. Lastly, the role of the assumed dispersion is more broadly explored for Cu–Ge interfaces. The prediction of thermal boundary conductance via the DMM with the assumed isotropic [100] dispersion relationships is compared to predictions with isotropic [111] and exact three-dimensional phonon dispersion relationships. It is found that regardless of the chosen crystallographic direction, the predictions of thermal boundary conductance using isotropic phonon dispersion relationships are within a factor of two of those predictions using an exact three-dimensional phonon dispersion.

Simple one-dimensional quantum-mechanical model for a particle attached to a surface

We present a simple one-dimensional quantum-mechanical model for a particle attached to a surface. It leads to the Schrödinger equation for a harmonic oscillator bounded on one side that we solve in terms of Weber functions and discuss the behaviour of the eigenvalues and eigenfunctions. We derive the virial theorem and other exact relationships as well as the asymptotic behaviour of the eigenvalues. We calculate the zero-point energy for model parameters corresponding to H adsorbed on Pd(1 0 0). The model is suitable for an advanced undergraduate or graduate course on quantum mechanics.

Acoustic temperature measurement in a rocket noise field

A 1 μm diameter platinum wire resistance thermometer has been used to measure temperature fluctuations generated during a static GEM-60 rocket motor test. Exact and small-signal relationships between acoustic pressure and acoustic temperature are derived in order to compare the temperature probe output with that of a 3.18 mm diameter condenser microphone. After preliminary plane wave tests yielded good agreement between the transducers within the temperature probe's ∼2 kHz bandwidth, comparison between the temperature probe and microphone data during the motor firing show that the ±∼3 K acoustic temperature fluctuations are a significant contributor to the total temperature variations.

A multi-expert approach for developing testing and diagnostic systems based on the concept-effect model

With the popularization of computer and communication technologies, researchers have attempted to develop computer-assisted testing and diagnostic systems to help students improve their learning performance on the Internet. In developing a diagnostic system for detecting students’ learning problems, it is difficult for individual teachers to address the exact relationships between the test items and the concepts. To cope with this problem, this study proposes an innovative approach to eliciting and integrating the weightings of test item-concept relationships from multiple experts. Based on the proposed approach, a testing and diagnostic system has been implemented; moreover, an experiment was conducted to evaluate the performance of our approach. By analyzing the results from four groups of students using learning suggestions provided by different models, it was found that the learning performance of the students who received learning suggestions by applying the innovative approach was significantly better than for those who received guidance based on the original model.

Ancestry and Pathology in King Tutankhamun's Family

The New Kingdom in ancient Egypt, comprising the 18th, 19th, and 20th dynasties, spanned the mid-16th to the early 11th centuries bc. The late 18th dynasty, which included the reigns of pharaohs Akhenaten and Tutankhamun, was an extraordinary time. The identification of a number of royal mummies from this era, the exact relationships between some members of the royal family, and possible illnesses and causes of death have been matters of debate. To introduce a new approach to molecular and medical Egyptology, to determine familial relationships among 11 royal mummies of the New Kingdom, and to search for pathological features attributable to possible murder, consanguinity, inherited disorders, and infectious diseases. From September 2007 to October 2009, royal mummies underwent detailed anthropological, radiological, and genetic studies as part of the King Tutankhamun Family Project. Mummies distinct from Tutankhamun's immediate lineage served as the genetic and morphological reference. To authenticate DNA results, analytical steps were repeated and independently replicated in a second ancient DNA laboratory staffed by a separate group of personnel. Eleven royal mummies dating from circa 1410-1324 bc and suspected of being kindred of Tutankhamun and 5 royal mummies dating to an earlier period, circa 1550-1479 bc, were examined. Microsatellite-based haplotypes in the mummies, generational segregation of alleles within possible pedigree variants, and correlation of identified diseases with individual age, archeological evidence, and the written historical record. Genetic fingerprinting allowed the construction of a 5-generation pedigree of Tutankhamun's immediate lineage. The KV55 mummy and KV35YL were identified as the parents of Tutankhamun. No signs of gynecomastia and craniosynostoses (eg, Antley-Bixler syndrome) or Marfan syndrome were found, but an accumulation of malformations in Tutankhamun's family was evident. Several pathologies including Köhler disease II were diagnosed in Tutankhamun; none alone would have caused death. Genetic testing for STEVOR, AMA1, or MSP1 genes specific for Plasmodium falciparum revealed indications of malaria tropica in 4 mummies, including Tutankhamun's. These results suggest avascular bone necrosis in conjunction with the malarial infection as the most likely cause of death in Tutankhamun. Walking impairment and malarial disease sustained by Tutankhamun is supported by the discovery of canes and an afterlife pharmacy in his tomb. Using a multidisciplinary scientific approach, we showed the feasibility of gathering data on Pharaonic kinship and diseases and speculated about individual causes of death.

A Rare Coronary Anomaly: One Ostium Fits All

Coronary anomalies affect a small percentage of the general population. A solitary coronary ostium in the absence of other major congenital anomalies is very rare. We describe a case of a patient, admitted to our cardiology department with an acute myocardial infarction. A coronary angiogram shows a solitary ostium originating from the right sinus of Valsalva with the left anterior descending coronary artery (LAD) ventral to the pulmonary artery and the circumflex artery (Cx) following its course retroaortically. The theoretical variant of this type of malformation has been described but has not been reported in a clinical case before. Coronary anomalies are usually detected during coronary angiography, but exact course determination and relationships are difficult to visualize. The use of cardiac computed tomography (CCT) allows visualization of the coronary anatomy in a 3-dimensional image and demonstrated an added value to coronary angiography.

Performance/Robustness Limit Evaluation for Lyapunov-Stable Nonlinear Plants

Lyapunov-stable nonlinear plants can be approximated by an LTI model in many cases. If this approximation is obtained then it is possible to construct a G2DOF control system. The paper presents a new approach how the important relationships between the actuator, process and design parameters furthermore robustness measures can be determined. In this decomposition method the optimal control design for two-degree of freedom time delay control systems is discussed. Using a proper CAD algorithm the exact relationships can be plotted and the ultimate robustness limit of any control can be explicitly calculated.

Angiotensin II, Oxidant Signaling, and Hypertension

It has been 30 years since landmark studies by Johnson and Brody 1 revealed a pivotal role for the forebrain circumventricular organs (CVOs) in experimental hypertension. We have since come to understand that these small midline structures, mounted along the cerebral ventricles and lacking well-formed blood-brain barriers, shoulder a huge responsibility for maintaining the delicate balance of cardiovascular and body fluid homeostases. With their exotic cytology and morphology, including “neuron-like” cells lying free on the ependymal surface and unusually dense and complex fenestrated capillary networks, the CVOs are involved in a remarkable array of homeostatic functions ranging from thirst and salt appetite to vasopressin release and sympathetic outflow.2 With the study by Lob et al in this issue of Hypertension, 3 we must also consider adding to this list the key role that CVOs play in linking central and peripheral mechanisms of hypertension through activation of peripheral T lymphocytes. If proven true, these findings could have broad implications for a unifying hypothesis of how the central nervous system, the vasculature, and possibly other peripheral organs, including the kidney, are involved in the etiology of hypertension. The first of 2 major findings in the study by Lob et al 3 supports and extends previous reports that reactive oxygen species signaling in the subfornical organ (SFO), a key forebrain CVO, is critical in angiotensin II (Ang II)–mediated regulation of blood pressure and hypertension. 4,5 Using an established viral gene transfer approach that induces robust transgene expression nearly exclusively in the SFO, 6 Lob et al3 show that SFO-targeted ablation of endogenous extracellular superoxide dismutase (SOD3), 1 of 3 isozymes in mammals that catalyzes dismutation of superoxide (O2 ), causes a significant elevation in basal blood pressure. In addition, deletion of SOD3 in the SFO increases the sensitivity to systemic Ang II at a dose that does not normally affect blood pressure in mice. These studies using gene deletion lead to a similar general conclusion as was made earlier using gene overexpression, namely, that elevated levels of O2 in the SFO lead to hypertension. What is new and important here is the unmasking of a key role for the extracellular form of SOD. In previous studies, we showed that adenoviral-mediated overexpression of cytoplasmic Cu/Zn SOD or mitochondrial SOD but not SOD3 in the SFO interfered with the pressor effects of Ang II. 4,5 However, as shown earlier and reiterated in the study by Lob et al,3 SOD3 is expressed at high basal levels in SFO. This may explain why additional overexpression of this form of the enzyme failed to inhibit the pressor effects of Ang II in our earlier studies. The use of Cre-loxP technology and selective deletion of endogenous SOD3 in the present study elegantly reveal that extracellular O2 signaling in SFO is also important. Future analysis of the relative expression, distribution, and functional role of these 3 SOD isozymes in SFO will be important in understanding the mechanisms of central

Invariances of frame sequences under perturbations

This paper determines the exact relationships that hold among the major Paley–Wiener perturbation theorems for frame sequences. It is shown that major properties of a frame sequence such as excess, deficit, and rank remain invariant under Paley–Wiener perturbations, but need not be preserved by compact perturbations. For localized frames, which are frames with additional structure, it is shown that the frame measure function is also preserved by Paley–Wiener perturbations.

A second species of Botryolepraria from the Neotropics and the phylogenetic placement of the genus within Ascomycota

Botryolepraria neotropica is described as new species from Bolivia, Cuba, and Peru. The phylogenetic affinities of the new species as well as of B. lesdainii are inferred by mean of the LSU and ITS regions of the fungal nuclear genome and Bayesian and ML phylogenetic inference. Our results showed that Botryolepraria belongs to the order Verrucariales, although the exact phylogenetic relationships are still unresolved.

Dynamics of the Jacobian matrices arising in three-dimensional Euler equations: application of Riccati theory

An attempt is made to remove, at least partially, the non-local nature associated with the pressure term of the incompressible Euler equations. We consider the dynamics of the Jacobian matrix J ( t ) relating spatial and material coordinates in incompressible three-dimensional Euler equations. By applying the theory of matrix-valued Riccati equations to the velocity gradient tensor V ( t ) assuming time-symmetric pressure Hessian, we derive an identity which is local in material coordinates for a fluid particle with det V (0)≠0, as a result of invariance under time-reversal. This imposes constraints on the time evolution of the velocity gradients and generates a chain of exact infinite relationships on the Taylor coefficients of V ( t ) in time. Some of the first few are explicitly given. As a corollary, we prove that if the evolution of the velocity gradient is symmetric with regard to time V ( t )= V (− t ), it must be a constant and . The key results herein may be summarized in equations ( 3.10 ) and ( 3.11 ).

Estimate of incompleteness error of moisture absorption in coulometric hygrometers

One of the most important components of the error of flow-through coulomometric hygrometers is that due to “moisture transit,” or loss. Exact relationships between this error and the fraction of electrolytic current from the control part of a coulometric cell for both fresh (“new”) cells (i.e., those that been regenerated) and cells that are in the aging process are obtained. It is shown that it is possible to determine and take into account this error in the measurement process.

Effect of saving motives and horizon on saving behaviors

The purpose of this research is to explore saving motives and saving horizon using a large, nationally representative dataset, the Survey of Consumer Finances. The framework is based on prospect theory, in which consumption and saving decisions are based on a reference point rather than on lifetime income. Prospect theory also posits that individuals construct various mental accounts, thereby allowing for households to have multiple saving motives. Since prospect theory does not assume that saving decisions are based on lifetime income, saving horizons are allowed to vary. The emergency and retirement saving motives are found to significantly increase the likelihood of saving regularly. Longer saving horizons are also found to have a highly significant effect on the likelihood of saving, while poor health is shown to have a significantly negative effect on the likelihood of saving. The results show that the saving motives held by households differ by saving horizon, but the exact relationships are unclear. Further research on the link between saving motives, saving horizon, and saving behaviors is needed. It is important for financial professionals and educators to consider a household’s saving goals, saving horizon, and health status when making recommendations or developing financial plans.

Low-Power Snoop Architecture for Synchronized Producer-Consumer Embedded Multiprocessing

We introduce a cross-layer customization methodology where application knowledge regarding data sharing in producer-consumer relationships is used in order to aggressively eliminate unnecessary and predictable snoop-induced cache lookups even for references to shared data, thus, achieving significant power reductions with minimal hardware cost. The technique exploits application-specific information regarding the exact producer-consumer relationships between tasks as well as information regarding the precise timing of synchronized accesses to shared memory buffers by their corresponding producers and/or consumers. Snoop-induced cache lookups for accesses to the shared data are eliminated when it is ensured that such lookups will not result in extra knowledge regarding the cache state in respect to the other caches and the memory. Our experiments show average power reductions of more than 80% compared to a general-purpose snoop protocol.

Nonclassical Composition Fronts in Nonlinear Chromatography: Delta-Shock

The local equilibrium theory of chromatography is applied to study binary systems subject to the mixed generalized Langmuir isotherm, ni = Hici/(1 − K1c1 + K2c2) (i = 1, 2), where components 1 and 2 are anti-Langmuir-like and Langmuir-like, respectively. Riemann problems, where a stream of a given composition is fed to a column initially saturated at a different composition, are analyzed. Within the hyperbolic region of the hodograph plane close to the origin, it is shown that such Riemann problems admit not only classical solutions, consisting of constant states separated by simple wave and shock wave transitions, but also nonclassical solutions, namely including a continuous nonsimple wave transition and a delta-shock. The latter can be viewed as a traveling spike of growing strength superimposed to the discontinuity separating the initial and the feed states. Exact conditions for the occurrence of classical and nonclassical solutions are derived. Thus, this work adds two new types of composition fronts to the classical ones already known in nonlinear chromatography. In the case of the delta-shock, the most striking new transition, it is possible to derive exact relationships for its properties, including the slope of its image in the physical plane, i.e. the reciprocal of its propagation speed, dt/dz = {1/W}{1 + ν((H1K2[n2] − H2K1[n1])/(H1K2[c2] − H2K1[c2]))}, where the symbol [·] denotes the jump across the discontinuity of the quantity enclosed. These analytical expressions match the results obtained through numerical simulations. The physical legitimacy of the model considered in this work is demonstrated theoretically and is further supported by the experimental evidence of the existence of delta-shocks that has been recently provided [Mazzotti et al. J. Chromatogr., submitted].

Contributions of vision–proprioception interactions to the estimation of time-varying hand and target locations

We investigated the relative importance of vision and proprioception in estimating target and hand locations in a dynamic environment. Subjects performed a position estimation task in which a target moved horizontally on a screen at a constant velocity and then disappeared. They were asked to estimate the position of the invisible target under two conditions: passively observing and manually tracking. The tracking trials included three visual conditions with a cursor representing the hand position: always visible, disappearing simultaneously with target disappearance, and always invisible. The target's invisible displacement was systematically underestimated during passive observation. In active conditions, tracking with the visible cursor significantly decreased the extent of underestimation. Tracking of the invisible target became much more accurate under this condition and was not affected by cursor disappearance. In a second experiment, subjects were asked to judge the position of their unseen hand instead of the target during tracking movements. Invisible hand displacements were also underestimated when compared with the actual displacement. Continuous or brief presentation of the cursor reduced the extent of underestimation. These results suggest that vision-proprioception interactions are critical for representing exact target-hand spatial relationships, and that such sensorimotor representation of hand kinematics serves a cognitive function in predicting target position. We propose a hypothesis that the central nervous system can utilize information derived from proprioception and/or efference copy for sensorimotor prediction of dynamic target and hand positions, but that effective use of this information for conscious estimation requires that it be presented in a form that corresponds to that used for the estimations.

Platelets and fibrinogen facilitate each other in protecting tumor cells from natural killer cytotoxicity

The functions of platelets and fibrinogen in protecting tumor cells from natural killer cytotoxicity have been discussed for more than 20 years. However, their exact roles and relationships in the process are still not clear. In this study, we show that tumor cells prefer to adhere to fibrinogen than to platelets, and fibrinogen can enhance the adhesion of tumor cells to platelets. Beta3 integrin plays an important role in the adhesion of B16F10 to platelets enhanced by fibrinogen. In the presence of thrombin, fibrinogen forms dense fibrin(ogen) layers around tumor cells. Tumor cells can induce platelets to aggregate and form thrombin. Platelets, as well as thrombin, can help fibrinogen protect tumor cells from lethal contact with natural killer cells and natural killer cytotoxicity. Hirudin, a specific inhibitor of thrombin, can reverse the effect of platelets on fibrinogen in blocking natural killer cytotoxicity. Our results suggest that fibrinogen helps platelets to adhere to tumor cells, and platelets in turn promote more fibrinogen to aggregate around tumor cells by forming thrombin. They facilitate each other in protecting tumor cells from natural killer cytotoxicity.