Size-frequency distributions and physical properties of chondrules from x-ray computed microtomography and digital data extraction.

Within this work, we present the first true three-dimensional (3D) analysis of chondrule size. Knowledge about the physical properties of chondrules is important for validating astrophysical theories concerning chondrule formation and their aggregation into the chondritic meteorites (known as chondrites) that contain them. The classification of chondrites into chemical groups also relies on chondrule properties, including their dimensions.

Chondrules reveal large-scale outward transport of inner Solar System materials in the protoplanetary disk.

Dynamic models of the protoplanetary disk indicate there should be large-scale material transport in and out of the inner Solar System, but direct evidence for such transport is scarce. Here we show that the εTi-εCr-ΔO systematics of large individual chondrules, which typically formed 2 to 3 My after the formation of the first solids in the Solar System, indicate certain meteorites (CV and CK chondrites) that formed in the outer Solar System accreted an assortment of both inner and outer Solar System materials, as well as material previously unidentified through the analysis of bulk meteorites. Mixing with primordial refractory components reveals a "missing reservoir" that bridges the gap between inner and outer Solar System materials.

Reducing Supervision of Quantitative Image Analysis of Meteorite Samples.

When selecting a method for determining modal mineralogy and elemental composition of geological samples (e.g., meteorites), a number of factors should be considered, includingthe number of objects or the area to be analyzed; the scale of expected chemical variation; instrument time restrictions; and post-processing time.

Influence of Hyperglycemia During Different Phases of Ischemic Preconditioning on Cardioprotection-A Focus on Apoptosis and Aggregation of Granulocytes.

Background: Ischemic preconditioning (IPC) protects the myocardium against ischemia/reperfusion injury. Evidence suggests that hyperglycemia inhibits IPC-induced cardioprotection. The effects of hyperglycemia initiated during different phases of IPC on myocardial injury were characterized with emphasis on apoptosis and aggregation of polymorphonuclear granulocytes (PMN).

Fine-grained Material Associated with a Large Sulfide returned from Comet 81P/Wild 2.

In a consortium analysis of a large particle captured from the coma of comet 81P/Wild 2 by the Stardust spacecraft, we report the discovery of a field of fine-grained material (FGM) in contact with a large sulfide particle. The FGM was partially located in an embayment in the sulfide. As a consequence, some of the FGM appears to have been protected from damage during hypervelocity capture in aerogel.

Effect of polychromatic x-ray microtomography imaging on the amino acid content of the Murchison CM chondrite.

X-ray microcomputed tomography is a useful means of characterizing cosmochemical samples such as meteorites or robotically returned samples. However, there are occasional concerns that the use of μCT may be detrimental to the organic components of a chondrite. Small organic compounds such as amino acids comprise up to ~10% of the total solvent extractable carbon in CM carbonaceous chondrites.

Blunted Respiratory Responses in the Streptozotocin-Induced Alzheimer's Disease Rat Model.

Alzheimer's disease (AD) is known for the progressive decline of cognition and memory. In addition to these disease-defining symptoms, impairment of respiratory function is frequently observed and often expressed by sleep-disordered breathing or reduced ability to adjust respiration when oxygen demand is elevated. The mechanisms for this are widely unknown.

Differences in perception of gerotranscendence behaviors between college students and community-dwelling older adults.

Within the field of gerontology, several different theories have attempted to explain common psychological and social changes associated with the aging process. The Theory of Gerotranscendence is one such theory which purports that a shift in meta-perspective from a more materialistic and pragmatic view of the world to a more cosmic and transcendent one occurs as we age. Corresponding with this shift in meta-perspective, the individual exhibits certain behaviors that could be mistaken as signs of psychopathology if viewed based on the assumptions of more culturally-assimilated theories of aging.

Imaging samples in silica aerogel using an experimental point spread function.

Light microscopy is a powerful tool that allows for many types of samples to be examined in a rapid, easy, and nondestructive manner. Subsequent image analysis, however, is compromised by distortion of signal by instrument optics. Deconvolution of images prior to analysis allows for the recovery of lost information by procedures that utilize either a theoretically or experimentally calculated point spread function (PSF).

Paleomagnetism. Solar nebula magnetic fields recorded in the Semarkona meteorite.

Magnetic fields are proposed to have played a critical role in some of the most enigmatic processes of planetary formation by mediating the rapid accretion of disk material onto the central star and the formation of the first solids. However, there have been no experimental constraints on the intensity of these fields. Here we show that dusty olivine-bearing chondrules from the Semarkona meteorite were magnetized in a nebular field of 54 ± 21 microteslas.

Evaluation of the Fatigue Performance and Degradability of Resorbable PLDLLA-TMC Osteofixations.

The fatigue performance of explanted in-situ degraded osteofixations/osteosyntheses, fabricated from poly (70L-lactide-co-24DL-lactide-6-trimethylane-carbonate or PLDLLA-TMC) copolymer was compared to that of virgin products. The fatigue test was performed on 21 explants retrieved from 12 women and 6 men; 16-46 years by a custom-designed three-point bend apparatus using a staircase method and a specified failure criterion (an increase of the deflection of the specimen > 1 mm) with run-out designated as "no failure" after 150,000 loading cycles. While all the virgin products showed run-out at 38N, all of the specimens fabricated from explants failed at this load level.

Radar-enabled recovery of the Sutter's Mill meteorite, a carbonaceous chondrite regolith breccia.

Doppler weather radar imaging enabled the rapid recovery of the Sutter's Mill meteorite after a rare 4-kiloton of TNT-equivalent asteroid impact over the foothills of the Sierra Nevada in northern California. The recovered meteorites survived a record high-speed entry of 28.6 kilometers per second from an orbit close to that of Jupiter-family comets (Tisserand's parameter = 2.

Radioactive elements on Mercury's surface from MESSENGER: implications for the planet's formation and evolution.

The MESSENGER Gamma-Ray Spectrometer measured the average surface abundances of the radioactive elements potassium (K, 1150 ± 220 parts per million), thorium (Th, 220 ± 60 parts per billion), and uranium (U, 90 ± 20 parts per billion) in Mercury's northern hemisphere. The abundance of the moderately volatile element K, relative to Th and U, is inconsistent with physical models for the formation of Mercury requiring extreme heating of the planet or its precursor materials, and supports formation from volatile-containing material comparable to chondritic meteorites. Abundances of K, Th, and U indicate that internal heat production has declined substantially since Mercury's formation, consistent with widespread volcanism shortly after the end of late heavy bombardment 3.

The major-element composition of Mercury's surface from MESSENGER X-ray spectrometry.

X-ray fluorescence spectra obtained by the MESSENGER spacecraft orbiting Mercury indicate that the planet's surface differs in composition from those of other terrestrial planets. Relatively high Mg/Si and low Al/Si and Ca/Si ratios rule out a lunarlike feldspar-rich crust. The sulfur abundance is at least 10 times higher than that of the silicate portion of Earth or the Moon, and this observation, together with a low surface Fe abundance, supports the view that Mercury formed from highly reduced precursor materials, perhaps akin to enstatite chondrite meteorites or anhydrous cometary dust particles.

Sevoflurane-induced preconditioning: impact of protocol and aprotinin administration on infarct size and endothelial nitric-oxide synthase phosphorylation in the rat heart in vivo.

Background: Sevoflurane induces preconditioning (SevoPC). The effect of aprotinin and the involvement of endothelial nitric-oxide synthase (NOS) on SevoPC are unknown. We investigated (1) whether SevoPC is strengthened by multiple preconditioning cycles, (2) whether SevoPC is blocked by aprotinin, and (3) whether endothelial NOS plays a crucial role in SevoPC.

Single therapeutic and supratherapeutic doses of laropiprant, a selective prostaglandin D2 receptor 1 antagonist, do not prolong the QTcF interval in healthy volunteers.

Laropiprant (LRPT), a prostaglandin D(2) receptor-1 antagonist shown to reduce niacin-induced flushing symptoms, has been combined with niacin for treatment of dyslipidemia. This study evaluated the effects of LRPT (50 mg and 600 mg, respectively) on the QT interval with Fridericia's correction (QTcF). QTcF measurements were made over a 24-hour period following administration of single-dose moxifloxacin 400 mg, LRPT 50 mg, LRPT 600 mg, or placebo.

Comparison of the tolerability of recombinant human hyaluronidase + normal saline and recombinant human hyaluronidase + lactated ringer's solution administered subcutaneously: A phase IV, double-blind, randomized pilot study in healthy volunteers.

Background: Recombinant human hyaluronidase (rHuPH20) (150 U) is approved by the US Food and Drug Administration to facilitate subcutaneous fluid administration in adults and children.

Objective: This Phase IV, double-blind, randomized pilot study was designed to compare the tolerability, flow rate, and safety profile of subcutaneous infusions of normal saline (NS) and lactated Ringer's (LR) solutions following subcutaneous administration of rHuPH20.

Methods: Healthy volunteers received 1 mL rHuPH20 (150 U) in each thigh, followed by simultaneous gravity-driven subcutaneous infusions of 500 mL of LR solution into 1 thigh and NS solution into the contralateral thigh.

Impact of preconditioning protocol on anesthetic-induced cardioprotection in patients having coronary artery bypass surgery.

Objective: Anesthetic preconditioning may contribute to the cardioprotective effects of sevoflurane in patients having coronary artery bypass surgery. We investigated whether 2 different sevoflurane administration protocols can induce preconditioning in patients having coronary artery bypass.

Methods: Thirty patients were randomly allocated to 1 of 3 groups.

Effects of aspirin when added to the prostaglandin D2 receptor antagonist laropiprant on niacin-induced flushing symptoms.

Niacin is an effective lipid-modifying therapy whose use has been limited by suboptimal tolerability. The adverse effect of flushing is due to prostaglandin D2 (PGD2)-mediated cutaneous vasodilation. Adjunctive treatment with the PGD2 receptor antagonist laropiprant significantly reduces the incidence and severity of niacin-induced flushing.

Ischemic preconditioning phosphorylates mitogen-activated kinases and heat shock protein 27 in the diabetic rat heart.

Diabetes mellitus blocks protection by ischemic preconditioning (IPC), but the mechanism is not known. We investigated the effect of ischemic preconditioning on mitogen-activated protein kinases (extracellular signal-regulated kinases 1 and 2, c-Jun N-terminal kinases, p38 mitogen-activated kinase) and heat shock protein 27 phosphorylation in diabetic and nondiabetic rat hearts in vivo. Two groups of anaesthetized nondiabetic and diabetic rats underwent a preconditioning protocol (3 cycles of 3 min coronary artery occlusion and 5 min of reperfusion).

Blockade of anaesthetic-induced preconditioning in the hyperglycaemic myocardium: the regulation of different mitogen-activated protein kinases.

Preconditioning by volatile anaesthetics is blocked by hyperglycaemia. The regulation of mitogen-activated protein kinases during this effect has yet not been investigated. For infarct size measurements, anaesthetized rats were subjected to 25 min coronary artery occlusion followed by 120 min reperfusion.

Influence of the interleukin-converting enzyme inhibitor HMR-3480 on myocardial stunning in pigs in vivo.

Background: The proinflammatory cytokine interleukin-1 beta is converted into its active form by interleukin-1 beta-converting enzyme (ICE). Circulating cytokines may promote myocardial dysfunction (stunning) after ischemia.

Objective: To investigate whether ICE inhibition by HMR-3840 improves myocardial stunning in vivo.

The formation conditions of chondrules and chondrites.

Chondrules, which are roughly millimeter-sized silicate-rich spherules, dominate the most primitive meteorites, the chondrites. They formed as molten droplets and, judging from their abundances in chondrites, are the products of one of the most energetic processes that operated in the early inner solar system. The conditions and mechanism of chondrule formation remain poorly understood.

Absolute bioavailability of sitagliptin, an oral dipeptidyl peptidase-4 inhibitor, in healthy volunteers.

The purpose of this study was to determine the absolute bioavailability of sitagliptin, an orally active, potent and highly selective dipeptidyl peptidase-4 inhibitor recently approved in the United States for the treatment of type 2 diabetes. The effect of a high fat meal on sitagliptin pharmacokinetics was also assessed. The study was performed in two parts.