Fe-Al-rich tridymite-hercynite xenoliths with positive cerium anomalies: preserved lateritic paleosols and implications for Miocene climate

Abstract We report isotopic and chemical compositions of unusual tridymite -hercynite xenoliths in middle Miocene Niutoushan tholeiites from the southeast coastal area of China. These xenoliths are characterized by positive cerium (Ce) anomalies and extremely high Al 2 O 3 (32 -34 wt.%) and total iron oxide (20 -22%). . Their chemical and isotopic compositions suggest that these xenoliths represent preserved aluminous lateritic paleosols that are not genetically related to host tholeiites. These lateritic paleosols with strongly desilicated minerals were formed by intense chemical weathering under warm and humid tropical conditions (with annual average temperature of >19 jC and the annual rainfall of >165 cm) in SE China during the interval from 17 to 15 Ma. The formation age of the paleosols corresponds to a period characterized by slow uplift of the Himalayan -Tibetan Plateau region (and thus less consumption of CO 2 ) after 17 Ma, and eruptions of 17 -15 Ma Columbia River flood basalts, the Vogelsberg basalts, and eastern China basalts (and thus more input of CO 2 into the atmosphere). The tridymite -hercynite xenoliths in the Niutoushan basalts thus preserve evidence of extraordinary climatic greenhouse conditions in the middle Miocene that would otherwise have been lost by the erosion of paleosols.

VCAM-1/α4β1 Integrin Interaction is Crucial for Prompt Recruitment of Immune T Cells into the Brain During the Early Stage of Reactivation of Chronic Infection with \u3cem\u3eToxoplasma gondii\u3c/em\u3e to Prevent Toxoplasmic Encephalitis

Reactivation of chronic infection with Toxoplasma gondii can cause life-threatening toxoplasmic encephalitis in immunocompromised individuals. We examined the role of VCAM-1/α4β1 integrin interaction in T cell recruitment to prevent reactivation of the infection in the brain. SCID mice were infected and treated with sulfadiazine to establish a chronic infection. VCAM-1 and ICAM-1 were the endothelial adhesion molecules detected on cerebral vessels of the infected SCID and wild-type animals. Immune T cells from infected wild-type mice were treated with anti-α4 integrin or control antibodies and transferred into infected SCID or nude mice, and the animals received the same antibody every other day. Three days later, sulfadiazine was discontinued to initiate reactivation of infection. Expression of mRNAs for CD3δ, CD4, CD8β, gamma interferon (IFN-γ), and inducible nitric oxide synthase (NOS2) (an effector molecule to inhibit T. gondii growth) and the numbers of CD4+ and CD8+ T cells in the brain were significantly less in mice treated with anti-α4 integrin antibody than in those treated with control antibody at 3 days after sulfadiazine discontinuation. At 6 days after sulfadiazine discontinuation, cerebral tachyzoite-specific SAG1 mRNA levels and numbers of inflammatory foci associated with tachyzoites were markedly greater in anti-α4 integrin antibody-treated than in control antibody-treated animals, even though IFN-γ and NOS2 mRNA levels were higher in the former than in the latter. These results indicate that VCAM-1/α4β1 integrin interaction is crucial for prompt recruitment of immune T cells and induction of IFN-γ-mediated protective immune responses during the early stage of reactivation of chronic T. gondii infection to control tachyzoite growth

Case report: Aggressive progression of acute heart failure due to juvenile tuberculosis-associated Takayasu arteritis with aortic stenosis and thrombosis

BackgroundTakayasu arteritis (TA) is a chronic granulomatous vasculitis with unknown pathophysiology. TA with severe aortic obstruction has a poor prognosis. However, the efficacy of biologics and appropriate timing of surgical intervention remain controversial. We report a case of tuberculosis (TB)-associated TA with aggressive acute heart failure (AHF), pulmonary hypertension (PH), thrombosis, and seizure, who failed to survive after surgery.Case presentationA 10-year-old boy who developed a cough with chest tightness, shortness of breath, hemoptysis with reduced left ventricular ejection fraction, PH, and increased C-reactive protein and erythrocyte sedimentation rate was hospitalized at the pediatric intensive care unit of our hospital. He had strongly positive purified protein derivative skin test and interferon-gamma release assay result. Computed tomography angiography (CTA) showed occlusion of proximal left subclavian artery and stenosis of descending aorta and upper abdominal aorta. His condition did not improve after administration of milrinone, diuretics, antihypertensive agents, and intravenous methylprednisolone pulse followed by oral prednisone. Intravenous tocilizumab was administered for five doses, followed by two doses of infliximab, but his HF worsened, and CTA on day 77 showed complete occlusion of the descending aorta with large thrombus. He had a seizure on day 99 with deterioration of renal function. Balloon angioplasty and catheter-directed thrombolysis were performed on day 127. Unfortunately, the child's heart function continued to deteriorate and died on day 133.ConclusionTB infection may be related to juvenile TA. The biologics, thrombolysis, and surgical intervention failed to achieve the anticipated effect in our case with aggressive AHF due to severe aortic stenosis and thrombosis. More studies are needed to determine the role of biologics and surgery in such dire cases

Thermodynamic modeling for an incrementally fractionated granite magma system: Implications for the origin of igneous charnockite

International audienceUnderstanding fractionation of silicic magma is crucial to advance our knowledge of differentiation of continental crust, enrichment of elements of economic interest, and plutonic–volcanic connection. Microstructural records afford critical appraisals for silicic magma fractionation, yet are rarely reported in granite plutons. Here we combine detailed microstructural observations and thermodynamic modeling to quantify the components and the conditions of silicic magma fractionation using the peraluminous Jiuzhou pluton (South China) as an example. The pluton shows compositional gradients from primitive orthopyroxene-bearing granite (charnockite) at stratigraphically low levels to relatively evolved orthopyroxene-free granite at stratigraphically high levels. Deviation of whole-rock compositions from metasediment-sourced experimental melts, and step-zoned plagioclase and alkali feldspar crystals in the exposed rocks suggest open-system fractionation by melt extraction, partial dissolution, and subsequent crystallization from trapped minimum melt. Crystal cluster and chain fabrics and viscous deformation are more abundant in the charnockites than in the overlying orthopyroxene-free granites, suggesting that gravitational, compaction-driven fractionation increased towards the bottom of the pluton. Field observations, thermodynamic modeling and petrographic studies further demonstrate that gravitational compaction reduces the trapped melt fraction of a crystal mush with thickness of ≥100 m from ∼30 wt% at the upper level to ∼10 wt% at the lower level of the pluton. Significant melt extraction restricted back-reaction with high-temperature phases during progressive crystallization, which preserved orthopyroxene during the solidification of granitic magma. The compositional, mineralogical and textural zoning of the Jiuzhou pluton suggests that incremental fractionation of granite systems may be an important process that produces compositionally zoned cumulate. Incremental fractionation may occur in many zoned granite plutons worldwide, causing their whole-rock composition to deviate from their primary melt composition. Detailed microstructural examination for these granite plutons may provide insights into the mechanism(s) for melt extraction and crystal accumulation of silicic magma, providing key insights towards quantifying fractionation of magma systems

Experimentally Verified Depth Control of an Unmanned Semi-Submersible Vehicle

This paper considers the control of one unmanned semi-submersible vehicle (USV), named BQ-01, where the submersible depth cannot exceed a few meters in the presence of environmental disturbances. Consequently, the depth control performance measures and the rejection of disturbances, such as those due to sea waves, must be within pre-determined ranges to ensure maximum use of such vehicles. This paper develops a control scheme that combines the state feedback control and rule-based supervision for depth control, where the entries in the feedback control matrix are adjusted by rules formulated from the state errors in the USV diving plane. Surge speed also plays an important role in adjusting control parameters because of its coupled relationship with the state depth of the diving plane. The results from sea trials are given and confirm the potential of the design

Re-Os isotopes in sulfides of mantle peridotites from SE China: Age constraints and evolution of lithospheric mantle

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Re-Os isotopes in mantle xenoliths from SE China: age constraints and evolution of lithospheric mantle

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