Bioanthropological analysis of human remains from the archaic and classic period discovered in Puyil cave, Mexico.

Objectives: Determine the geographic place of origin and maternal lineage of prehistoric human skeletal remains discovered in Puyil Cave, Tabasco State, Mexico, located in a region currently populated by Olmec, Zoque and Maya populations.

Materials And Methods: All specimens were radiocarbon (C) dated (beta analytic), had dental modifications classified, and had an analysis of 13 homologous reference points conducted to evaluate artificial cranial deformation (ACD). Following DNA purification, hypervariable region I (HVR-1) of the mitogenome was amplified and Sanger sequenced.

Natural incorporation of mercury in bone.

Mercury (Hg) is a highly toxic element that causes bone defects and malformations. Structure and surface analyses using quantitative x-ray diffraction using the Rietveld method, High-Resolution Transmission Electron Microscopy and nanodiffraction analyses, and Fourier-Transformed Infrared spectroscopy showed that bone enriched naturally with Hg (≤ 2.3 %) contained HgPO [(Hg)(PO)] and HgO.

Antibacterial clay against gram-negative antibiotic resistant bacteria.

Antibiotic resistant bacteria persist throughout the world because they have evolved the ability to express various defense mechanisms to cope with antibiotics and the immune system; thus, low-cost strategies for the treatment of these bacteria are needed, such as the usage of environmental minerals. This paper reports the antimicrobial properties of a clay collected from Brunnenberg, Germany, that is composed of ferroan saponite with admixtures of quartz, feldspar and calcite as well as exposed or hidden (layered at inner regions) nano Fe(0). Based on the growth curves (log phase) of six antibiotic resistant bacteria (4 gram-negative and 2 gram-positive), we concluded that the clay acted as a bacteriostat; however, the clay was only active against the gram-negative bacteria (except for resilient Klebsiella pneumonia).

Genetic Affiliation of Pre-Hispanic and Contemporary Mayas Through Maternal Linage.

Maya civilization developed in Mesoamerica and encompassed the Yucatan Peninsula, Guatemala, Belize, part of the Mexican states of Tabasco and Chiapas, and the western parts of Honduras and El Salvador. This civilization persisted approximately 3,000 years and was one of the most advanced of its time, possessing the only known full writing system at the time, as well as art, sophisticated architecture, and mathematical and astronomical systems. This civilization reached the apex of its power and influence during the Preclassic period, from 2000 BCE to 250 CE.

Role of bentonite clays on cell growth.

Bentonites, naturally occurring clays, are produced industrially because of their adsorbent capacity but little is known about their effects on human health. This manuscript reports on the effect of bentonites on cell growth behaviour. Bentonites collected from India (Bent-India), Hungary (Bent-Hungary), Argentina (Bent-Argentina), and Indonesia (Bent-Indonesia) were studied.

Oxidative stress inhibition and oxidant activity by fibrous clays.

Fibrous clays (sepiolite, palygorskite) are produced at 1.2m tonnes per year and have a wide range of industrial applications needing to replace long-fibre length asbestos. However, information on the beneficial effects of fibrous clays on health remains scarce.

Anti-inflammatory, anti-bacterial, and cytotoxic activity of fibrous clays.

Produced worldwide at 1.2m tons per year, fibrous clays are used in the production of pet litter, animal feed stuff to roof parcels, construction and rheological additives, and other applications needing to replace long-fiber length asbestos. To the authors' knowledge, however, information on the beneficial effects of fibrous clays on health remains scarce.

Lipid peroxidation and cytotoxicity induced by respirable volcanic ash.

This paper reports that the main component of respirable volcanic ash, allophane, induces lipid peroxidation (LP), the oxidative degradation of lipids in cell membranes, and cytotoxicity in murin monocyle/macrophage cells. Naturally-occurring allophane collected from New Zealand, Japan, and Ecuador was studied. The quantification of LP was conducted using the Thiobarbituric Acid Reactive Substances (TBARS) assay.

Anti-inflammatory and anti-bacterial activity, and cytotoxicity of halloysite surfaces.

Halloysite is a naturally-occurring nanomaterial occurring in the thousands of tons and that serves as biomaterial, with applications in the areas of biotechnology, pharmaceutical, and medical research. This study reports on the anti-inflammatory, cytotoxic, and anti-oxidant activity of halloysite Jarrahdale (collected at ∼ 45 km SE of Perth, Western Australia; JA), Dragon Mine (provided by Natural Nano Inc., Rochester, New York; NA), and Kalgoorie Archean (collected at Siberia, ∼ 85km NW of Kalgoorlie, West Australia; PA).

Oxidative stress induced by arsenopyrite and the role of desferrioxamine-B as radical scavenger.

Arsenopyrite (FeAsS) is one of the earth's primary mineral sources of As, yet its effects on cell damage remain largely unknown. This paper addresses the question whether FeAsS induces lipid peroxidation (LP), a major indicator of oxidative stress. Screening and monitoring of LP was conducted using Thiobarbituric Acid Reactive Substances (TBARSs) assay.

Adsorption and photocatalytic oxidation of formaldehyde on a clay-TiO2 composite.

We investigated the adsorption capacity and photocatalytic removal efficiency of formaldehyde using a hectorite-TiO(2) composite in a bench flow reactor. The same experimental conditions were applied to pure TiO(2) (Degussa P25) as a reference. The catalysts were irradiated with either a UVA lamp (365 nm) or with one of two UVC lamps of 254 nm and 254+185 nm, respectively.

Oxidative stress, cytoxicity, and cell mortality induced by nano-sized lead in aqueous suspensions.

This paper reports on the effect of aqueous and nano-particulated Pb on oxidative stress (lipid peroxidation), cytoxicity, and cell mortality. As determined by the Thiobarbituric Acid Reactive Substances (TBARS) method, only 6h after incubation aqueous suspensions bearing nano-sized PbO(2), soluble Pb(II), and brain-homogenate only suspensions, were determined to contain as much as ca. 7, 5, and 1 nmol TBARS mg protein(-1), respectively.

Determination of lipid peroxidation and cytotoxicity in calcium, magnesium, titanium and hectorite (SHCa-1) suspensions.

This paper reports data on the relative ability of CaO, CaCl2, MgO, MgCl2, TiO2, and hectorite (SHCa-1) to induce oxidative stress (as determined by lipid peroxidation, LP) in biological matrices. The effectiveness of structural (oxide form) versus soluble Ca and Mg to induce LP is compared. An assessment on cytotoxicity as affected by soluble and structural Ca, Mg, TiO2 and SHCa-1 is also addressed.

Arsenic(III) methylation in betaine-nontronite clay-water suspensions under environmental conditions.

This paper reports arsenic methylation in betaine-nontronite clay-water suspensions under environmental conditions. Two nontronites (<0.05 mm), NAu-1 (green color, Al-enriched) and NAu-2 (brown color, Al-poor, contains tetrahedral Fe) from Uley Mine - South Australia were selected for this study.

Lipid peroxidation induced by expandable clay minerals.

Small-sized environmental particles such as 2:1 phyllosilicates induce oxidative stress, a primary indicator of cell damage and toxicity. Herein, potential hazards of clay particle uptake are addressed. This paper reports that the content and distribution of structural Fe influence the ability of expandable clay minerals to induce lipid peroxidation (LP), a major indicator of oxidative stress, in biological matrices.

Efficiency of clay--TiO2 nanocomposites on the photocatalytic elimination of a model hydrophobic air pollutant.

Clay-supported TiO2 photocatalysts can potentially improve the performance of air treatment technologies via enhanced adsorption and reactivity of target volatile organic compounds (VOCs). In this study, a benchtop photocatalytic flow reactor was used to evaluate the efficiency of hectorite-TiO2 and kaolinite-TiO2, two novel composite materials synthesized in our laboratory. Toluene, a model hydrophobic VOC and a common indoor air pollutant, was introduced in the air stream at realistic concentrations, and reacted under UVA (lamda(max) = 365 nm) or UVC (lamda(max) = 254 nm) irradiation.

Hydration/expansion and cation charge compensation modulate the Brønsted basicity of distorted clay water.

This letter addresses how iron redox cycling and the hydration properties of the exchangeable cation influence the Brønsted basicity of adsorbed water in 2:1 phyllosilicates. The probe pentachloroethane undergoes facile dehydrochlorination to tetrachloroethene, attributed to increases in the Brønsted basicity of near-surface hydrating water molecules following the reduction of structural Fe(III) to Fe(II). This dehydrochlorination process is studied in the presence of Na(+)- or K(+)-saturated Upton montmorillonite [(Na0.

Alteration of the surface charge of aluminum goethites by a sulfonic acid buffer.

Four samples of synthetic low-substitution Al-goethites (mol% Al<10) were incubated with 10 mM NaClO4 and 5 mM MES buffer (MES buffer (2-[N-morpholino]ethanesulfonic acid) at pH 5. It was found that MES buffer, although commonly used to control pH, profoundly affected the results of our electrophoretic mobility measurements. The presence of MES buffer caused a large decrease in EM values for unsubstituted goethite, from 5.

Linear free-energy relationship analysis of the fate of chlorinated 1- and 2-carbon compounds by redox-manipulated smectite clay minerals.

This paper expands on earlier work on the effect of molecular structure on the fate of a series of chlorinated 1- and 2-carbon compounds (RCl), including carbon tetrachloride, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, pentachloroethane, hexachloroethane, trichloroethene, tetrachloroethene, trichloronitromethane, and trichloroacetonitrile, in the presence of unaltered (SWa-U) and reduced (SWa-R) ferruginous smectite. A linear free-energy relationships (LFERs) analysis was conducted to explain kinetic data for RCl adsorption and dechlorination. Correlation analyses based on RCl hydration energies, hydrolysis rate constants, or bond dissociation energies were significant (r2 > 0.

Dehydrochlorination of 1,1,1-trichloroethane and pentachloroethane by microbially reduced ferruginous smectite.

Reduction of structural Fe(III) in smectite clay minerals has been identified as a means to promote dechlorination of polychlorinated ethanes, but its environmental significance has yet to be fully assessed because Fe reduction has normally been achieved by agents uncommon in the environment (e.g., dithionite).

Dechlorination of pentachloroethane by commercial Fe and ferruginous smectite.

Short-term experiments were conducted to investigate the effect of a commercial Fe and an iron-bearing clay mineral, ferruginuous smectite (SWa-1), on the degradation of pentachloroethane (PCA). After 3 h of contact time, SWa-1 catalyzed PCA dehydrochlorination to tetrachloroethene (PCE, 65% conversion), whereas commercial Fe promoted PCA stepwise dechlorination via dehydrochlorination (approximately 40% conversion) and subsequent PCE hydrogenolysis to trichloroethene (TCE). The addition of unaltered SWa-1 to commercial Fe led to a complete inhibition on TCE production, whereas the addition of reduced SWa-1 barely resulted in a 30% decrease.

Steady-state dissolution kinetics of aluminum-goethite in the presence of desferrioxamine-B and oxalate ligands.

This paper reports steady-state dissolution rates of synthetic low-substitution Al-goethites (mol % Al < 10) at pH 5 in the presence of the trihydroxamate siderophore, desferrioxamine B (DFO-B), and the common biological ligand, oxalate. The siderophore-promoted Fe release rate increased both with the level of Al substitution and with DFO-B concentration up to about 100 microM, after which a plateau occurred, suggesting a saturation effect from DFO-B adsorption as a precursor to dissolution. At concentrations above 200 microM, oxalate also enhanced the Fe release rate, which however was not influenced by Al substitution.