Unintended targeting of Dmp1-Cre reveals a critical role for Bmpr1a signaling in the gastrointestinal mesenchyme of adult mice

Cre/loxP technology has been widely used to study cell type-specific functions of genes. Proper interpretation of such data critically depends on a clear understanding of the tissue specificity of Cre expression. The Dmp1-Cre mouse, expressing Cre from a 14-kb DNA fragment of the mouse Dmp1 gene, has become a common tool for studying gene function in osteocytes, but the presumed cell specificity is yet to be fully established. By using the Ai9 reporter line that expresses a red fluorescent protein upon Cre recombination, we find that in 2-month-old mice, Dmp1-Cre targets not only osteocytes within the bone matrix but also osteoblasts on the bone surface and preosteoblasts at the metaphyseal chondro-osseous junction. In the bone marrow, Cre activity is evident in certain stromal cells adjacent to the blood vessels, but not in adipocytes. Outside the skeleton, Dmp1-Cre marks not only the skeletal muscle fibers, certain cells in the cerebellum and the hindbrain but also gastric and intestinal mesenchymal cells that express Pdgfra. Confirming the utility of Dmp1-Cre in the gastrointestinal mesenchyme, deletion of Bmpr1a with Dmp1-Cre causes numerous large polyps along the gastrointestinal tract, consistent with prior work involving inhibition of BMP signaling. Thus, caution needs to be exercised when using Dmp1-Cre because it targets not only the osteoblast lineage at an earlier stage than previously appreciated, but also a number of non-skeletal cell types

A modeling case for high atmospheric oxygen concentrations during the Mesozoic and Cenozoic

Changes in atmospheric oxygen concentration over Earth history are commonly related to the evolution of animals and plants. But there is no direct geochemical proxy for O2 levels, meaning that estimations rely heavily on modeling approaches. The results of such studies differ greatly, to the extent that today's atmospheric mixing ratio of 21% might be either the highest or lowest level during the past 200 m.y. Long-term oxygen sources, such as the burial in sediments of reduced carbon and sulfur species, are calculated in models by representation of nutrient cycling and estimation of productivity, or by isotope mass balance (IMB)—a technique in which burial rates are inferred in order to match known isotope records. Studies utilizing these different techniques produce conflicting estimates for paleoatmospheric O2, with nutrient-weathering models estimating concentrations close to, or above, that of the present day, and IMB models estimating low O2, especially during the Mesozoic. Here we re-assess the IMB technique using the COPSE biogeochemical model. IMB modelling is confirmed to be highly sensitive to assumed carbonate δ13C, and when this input is defined following recent compilations, predicted O2 is significantly higher and in reasonable agreement with that of non-IMB techniques. We conclude that there is no model-based support for low atmospheric oxygen concentrations during the past 200 m.y. High Mesozoic O2 is consistent with wildfire records and the development of plant fire adaptions, but links between O2 and mammal evolution appear more tenuous

Cost-Effectiveness of a Comprehensive Approach for Hypertension Control in Low-Income Settings in Argentina: Trial-Based Analysis of the Hypertension Control Program in Argentina

Background: A recent cluster randomized trial evaluating a multicomponent intervention showed significant reductions in blood pressure in low-income hypertensive subjects in Argentina. Objectives: To assess the cost-effectiveness of this intervention. Methods: A total of 1432 hypertensive participants were recruited from 18 primary health care centers. The intervention included home visits led by community health workers, physician education, and text messaging. Resource use and quality of life data using the three-level EuroQol five-dimensional questionnaire were prospectively collected. The study perspective was that of the public health care system, and the time horizon was 18 months. Intention-to-treat analysis was used to analyze cost and health outcomes (systolic blood pressure [SBP] change and quality-adjusted life-years [QALYs]). A 1 time gross domestic product per capita per QALY was used as the cost-effectiveness threshold (US $14,062). Results: Baseline characteristics were similar in the two arms. QALYs significantly increased by 0.06 (95$304 in the intervention group and US $154 in the control group (adjusted difference of US$140.18; 95% CI US $75.41–US$204.94). The incremental cost-effectiveness ratio was $3299 per QALY (95$26 per mm Hg of SBP (95% credible interval 13–46). Subgroup analysis showed that the intervention was cost-effective in all prespecified subgroups (age, sex, cardiovascular risk, and body mass index). Conclusions: The multicomponent intervention was cost-effective for blood pressure control among low-income hypertensive patients.Fil: Augustovski, Federico Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Chaparro, Martin. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Palacios, Alfredo. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Shi, Lizheng. University of Tulane; Estados UnidosFil: Beratarrechea, Andrea Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Irazola, Vilma. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Rubinstein, Adolfo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Efectividad Clínica y Sanitaria; ArgentinaFil: Mills, Katherine. University of Tulane; Estados UnidosFil: He, Jiang. University of Tulane; Estados UnidosFil: Pichón-Riviere, Andrés. Instituto de Efectividad Clínica y Sanitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Interface charged impurity scattering in semiconductor MOSFETs and MODFETs: temperature dependent resistivity and 2D "metallic" behavior

We present the results on the anomalous 2D transport behavior by employing Drude-Boltzmann transport theory and taking into account the realistic charge impurity scattering effects. Our results show quantitative agreement with the existing experimental data in several different systems and address the origin of the strong and non-monotonic temperature dependent resistivity.Comment: Presented at SIMD, Dec. 1999 in Hawaii. To be published in Superlattices and Microstructures, May 2000 issu

Design of a Water Environment Monitoring System Based on Wireless Sensor Networks

A water environmental monitoring system based on a wireless sensor network is proposed. It consists of three parts: data monitoring nodes, data base station and remote monitoring center. This system is suitable for the complex and large-scale water environment monitoring, such as for reservoirs, lakes, rivers, swamps, and shallow or deep groundwaters. This paper is devoted to the explanation and illustration for our new water environment monitoring system design. The system had successfully accomplished the online auto-monitoring of the water temperature and pH value environment of an artificial lake. The system's measurement capacity ranges from 0 to 80 °C for water temperature, with an accuracy of ±0.5 °C; from 0 to 14 on pH value, with an accuracy of ±0.05 pH units. Sensors applicable to different water quality scenarios should be installed at the nodes to meet the monitoring demands for a variety of water environments and to obtain different parameters. The monitoring system thus promises broad applicability prospects

The metallic resistance of a dilute two-dimensional hole gas in a GaAs quantum well: two-phase separation at finite temperature?

We have studied the magnetotransport properties of a high mobility two-dimensional hole gas (2DHG) system in a 10nm GaAs quantum well (QW) with densities in range of 0.7-1.6*10^10 cm^-2 on the metallic side of the zero-field 'metal-insulator transition' (MIT). In a parallel field well above B_c that suppresses the metallic conductivity, the 2DHG exhibits a conductivity g(T)~0.3(e^2/h)lnT reminiscent of weak localization. The experiments are consistent with the coexistence of two phases in our system: a metallic phase and a weakly insulating Fermi liquid phase having a percolation threshold close to B_c

Modeling hyperthermal events in the Mesozoic-Paleogene periods: a review

Hyperthermal events, which are characterized by rapid and extreme warming, occurred at several points throughout the Mesozoic to Paleogene periods. Model simulation studies have been conducted to investigate the mechanisms behind these events, including the carbon fluxes required to drive observed warming and isotope dynamics, the impact of warming on continental weathering, seawater pH, ocean anoxia, and the mechanism that terminated the warming. Studies using simple box models, Earth system box models, or 3D Earth system models have suggested that warming had a significant biogeochemical impact and would enhance continental weathering, increase ocean anoxia, and drive marine acidification. However, the magnitudes of these impacts remain debated and require further modeling work, as do the reconstructions of carbon fluxes and compositions. This review provides an overview of the current state of knowledge on hyperthermal events and proposes possible modeling development directions to better understand the causes and impacts of these events. Particularly, new long-term ‘semi-spatial’ Earth system models are promising tools for providing new solutions and perspectives on the biogeochemical responses to warming events and the carbon fluxes behind hyperthermal events from the Mesozoic to Paleogene periods

Acetonitrile­triaqua­[3-eth­oxy-1,8-(3,6,9-trioxaundecane-1,11-diyldi­oxy)-9H-xanthen-9-one]terbium(III) tris­(perchlorate)

In the title compound, [Tb(CH3CN)(C23H26O8)(H2O)3](ClO4)3, the Tb3+ atom is eight-coordinated by one N atom of an acetonitrile molecule, three water O atoms and four ligand O atoms. The Tb3+ atom is located on one side of the macrocycle and the carbonyl oxygen coordinated to the terbium [Tb1—O1= 2.210 (3) Å] is bent out of the xanthone plane by 0.514 (3) Å. The geometry around terbium is a distorted two-capped trigonal prism

In polycistronic Qβ RNA, single-strandedness at one ribosome binding site directly affects translational initiations at a distal upstream cistron

In Qβ RNA, sequestering the coat gene ribosome binding site in a putatively strong hairpin stem structure eliminated synthesis of coat protein and activated protein synthesis from the much weaker maturation gene initiation site, located 1300 nucleotides upstream. As the stability of a hairpin stem comprising the coat gene Shine–Dalgarno site was incrementally increased, there was a corresponding increase in translation of maturation protein. The effect of the downstream coat gene ribosome binding sequence on maturation gene expression appeared to have occurred only in cis and did not require an AUG start codon or initiation of coat protein synthesis. In all cases, no structural reorganization was predicted to occur within Qβ RNA. Our results suggest that protein synthesis from a relatively weak translational initiation site is greatly influenced by the presence or absence of a stronger ribosome binding site located elsewhere on the same RNA molecule. The data are consistent with a mechanism in which multiple ribosome binding sites compete in cis for translational initiations as a means of regulating protein synthesis on a polycistronic messenger RNA

Nonmonotonic Temperature-dependent Resistance in Low Density 2D Hole Gases

The low temperature longitudinal resistance-per-square Rxx(T) in ungated GaAs/AlGaAs quantum wells of high peak hole mobility 1.7x10^6 cm^2/Vs is metallic for 2D hole density p as low as 3.8x10^9 cm-2. The electronic contribution to the resistance, R_{el}(T), is a nonmonotonic function of T, exhibiting thermal activation, R_{el}(T) ~ exp{-E_a/kT}, for kT<<E_F and a heretofore unnoted decay R_{el}(T) ~ 1/T for k_T>EF. The form of R_{el}(T) is independent of density, indicating a fundamental relationship between the low and high T scattering mechanisms in the metallic state