Regulation of zinc-responsive Slc39a5 (Zip5) translation is mediated by conserved elements in the 3′-untranslated region

Translation of the basolateral zinc transporter ZIP5 is repressed during zinc deficiency but Zip5 mRNA remains associated with polysomes and can be rapidly translated when zinc is repleted. Herein, we examined the mechanisms regulating translation of Zip5. The 3′-untranslated region (UTR) of Zip5 mRNA is well conserved among mammals and is predicted by mFOLD to form a very stable stem-loop structure. Three algorithms predict this structure to be flanked by repeated seed sites for miR-328 and miR-193a. RNAse footprinting supports the notion that a stable stem-loop structure exists in this 3′-UTR and electrophoretic mobility shift assays detect polysomal protein(s) binding specifically to the stem-loop structure in the Zip5 3′-UTR. miR-328 and miR-193a are expressed in tissues known to regulate Zip5 mRNA translation in response to zinc availability and both are polysome-associated consistent with Zip5 mRNA localization. Transient transfection assays using native and mutant Zip5 3′-UTRs cloned 3′ to luciferase cDNA revealed that the miRNA seed sites and the stem-loop function together to augment translation of Zip5 mRNA when zinc is replete

Archaeological Investigations of Alpine Ice Patches in the Selwyn Mountains, Northwest Territories, Canada

Inspired by the groundbreaking investigation of ice patch archaeology in Yukon Territory, the authors began exploring the Mackenzie, Selwyn, and Richardson Mountains for ice patch archaeological sites in 2000. Through remote sensing analysis, followed by intensive field surveys in the Selwyn and Mackenzie Mountains, we documented eight ice patch sites containing well-preserved archaeological artifacts and biological specimens. Twenty additional ice patches exhibit the key indicators of ice patch archaeological sites (permanent or intermittent ice and snow lenses containing caribou fecal matter, faunal material, or both), but so far these patches have not yielded artifacts. Collections from ice patches in the Selwyn Mountains include examples of three precontact hunting technologies: throwing dart (atlatl), bow-and-arrow, and snare. Atlatl technology, represented by the distal ends of two darts dating to 2410 and 2310 14C yr BP, predates bow-and-arrow technology, represented by two complete arrows, two distal shaft fragments, and a partial bow dating between 850 and 270 14C yr BP. A ground squirrel snare dates to 970 14C yr BP. Caribou dominates the faunal remains recovered from the ice patches. These data suggest that hunting on ice patches was part of a broader-spectrum summer subsistence economy focused on a broad alpine valley, known locally as K’atieh, and that hunters tended to target ice patches close to other subsistence locations in this area.Inspiré par les travaux révolutionnaires de l’archéologie des névés menés dans le territoire du Yukon, les auteurs ont commencé en l’an 2000 l’exploration des montagnes du Mackenzie, de Selwyn et de Richardson afin d’y trouver des sites archéologiques associés à des névés. L’analyse des données de la télédétection suivie d’un programme de prospection intensif dans les montagnes de Selwyn et du Mackenzie a permis de documenter huit sites de névés qui contiennent des objets archéo­logiques et des spécimens biologiques bien conservés. Vingt autres sites présentent les caractéristiques des sites archéolo­giques de névés (soit des lentilles de glace et de neige permanentes ou semi-permanentes contenant des matières fécales et (ou) de la faune), mais n’ont livré pour l’instant aucun artefact. Les collections des névés des montagnes Selwyn comprennent des exemplaires de trois systèmes d’armes de chasse antérieures au contact. La technique du tir au propulseur est représentée par les extrémités distales de deux lances datant de 2410 et 2310 années radiocarbones BP et est antérieure à celle de l’arc et de la flèche qui consiste en deux flèches complètes, deux fragments distaux de hampe et un arc incomplet datés entre 850 et 270 années radiocarbones BP. Un piège à spermophile date de 970 années radiocarbones BP. Les ossements de caribou dominent les restes de faune trouvés dans les névés. Ces données laissent entendre que la chasse dans les zones alpines faisait partie d’une économie de subsistance estivale dans laquelle un large éventail d’espèces était chassé. Ces activités de subsistance se concentraient dans les larges vallées alpines, connues localement sous le nom de K’atieh et les chasseurs avaient tendance à cibler les névés localisés à proximité des autres ressources de la région

The effect of dental chair light exposure duration on shear bond strength of orthodontic brackets : an in vitro study

The purpose of this study is to determine if the duration of exposure to the halogen overhead dental chair light has an effect on shear bond strength (SBS) of metal orthodontic brackets. One hundred twenty extracted human lower incisor teeth were divided into six groups (n=20/group). Each group was assigned a predetermined duration of exposure to the halogen dental chair light, set at a fixed distance, before being cured. Light exposure times of 0 minutes (Group 1-Control), 1 minute (Group 2), 2.5 minutes (Group 3), 5 minutes (Group 4), 10 minutes (Group 5), and 15 minutes (Group 6) were tested. Each tooth was subjected to an exclusion criteria examination, scrubbed of all debris, and imbedded in a PVC-stone fixture with the crown of the tooth exposed above the stone surface. All groups had orthodontic brackets bonded with the same materials and process, then light cured for 6 seconds using the Valo LED curing unit after their designated light exposure time. Groups were tested using an Instron E-1000 universal testing machine with a shear load test set at a speed of 1mm/min using a knife-edged chisel. Data was analyzed using a one-way ANOVA test. The Adhesive Remnant Index (ARI) was scored under 10x magnification. The ARI data was analyzed using the Chi-square test (p-value < 0.05). All control and experimental groups for each specific tooth type tested resulted in SBS within or above the clinically acceptable range. Statistically significant differences (p<.05) were found between the control and experimental groups for dental chair light exposure times of 5 minutes, 10 minutes and 15 minutes. A chi-square test determined that there was statistical significance when evaluating the frequency of ARI scores when light exposure duration was greater than 5 minutes. It can be concluded that dental chair light exposure in the 5 minute, 10 minute and 15 minute groups produced higher shear bond strength than those of the control, 1 minute and 2.5 minute groups. The dental chair light is capable of initiating polymerization and causing higher bond strengths than the clinical acceptability of 5.8-7.9 MPa, thus continued dental chair light exposure over 5 minutes is not recommended. The ARI analysis revealed that as bond strength increased, the fracture pattern shifted from most remaining adhesive attached to the tooth toward that attached to the bracket

A Thousand Years of Lost Hunting Arrows: Wood Analysis of Ice Patch Remains in Northwestern Canada

Discussions of the development of past hunting equipment generally focus on lithic and bone projectile points and foreshafts, as these are often the only elements remaining in archaeological sites. In the last 15 years, the archaeology of alpine ice patches has provided a unique opportunity to analyze hunting equipment over time and gain knowledge of the wooden elements on which the points are hafted. This paper describes the wood and morphometrical analysis of a collection of 27 arrow shafts from two ice patch regions of the western Canadian Subarctic. In both regions, two main categories of arrow shafts show the selection of specific pieces of wood, spruce (Picea sp.) on the one hand and birch (Betula sp.) on the other, with associated morphometrical characteristics. These shafts also share some characteristics that are distinct from those of Arctic and coastal arrow shafts. Shafts of pine (Pinus sp. sec. ponderosa) and hemlock (Tsuga sp.) were also identified in the southwestern Yukon Territory. The absence of correlation between the arrow shaft types and 14C dating raises the question of the significance of the arrow types and the potential for function, trade, or travel to explain the variation.Les discussions sur le développement des armes de chasse se concentrent généralement sur les pointes de projectile et les préhampes en matières lithiques et osseuses car ce sont ces éléments qui sont les plus souvent retrouvés dans les sites archéologiques. Ces quinze dernières années, l’archéologie des névés alpins nous donne l’opportunité unique d’analyser des équipements de chasse sur le long terme et de documenter les éléments en bois au bout desquels les pointes sont emmanchées. Dans cet article, nous décrivons l’analyse d’une collection de vingt-sept hampes de flèche en bois végétal provenant de deux régions de névés du Subarctique canadien. Dans les deux régions, on définit deux catégories principales de hampes de flèche qui montrent une sélection spécifique de pièces de bois d’épicéa (Picea sp.) et de bouleau (Betula sp.) auxquelles correspondent des caractéristiques morphométriques propres. Ces hampes partagent aussi des caractéristiques qui les distinguent de celles plus nordiques des côtes de l’Arctique. Des hampes faites en bois de pin (Pinus sp. sec. ponderosa) et de pruche (Tsuga sp.) ont également été identifiées dans le Sud-ouest du Territoire du Yukon. L’absence de corrélation entre les types de hampe de flèche et les dates radiocarbone soulève la question du sens à donner à ces types de flèche. Des facteurs tels que la fonction, les échanges ou des déplacements de personne sont envisagés

Morphology and Development of Ice Patches in Northwest Territories, Canada

Permanent ice patches in the western Canadian Subarctic have been recently identified as sources of cryogenically preserved artifacts and biological specimens. The formation, composition, and constancy of these ice patches have yet to be studied. As part of the Northwest Territories (NWT) Ice Patch Study, ground-penetrating radar (GPR) and ice coring were used to examine the stratigraphy and internal structure of two ice patches. Results show the patches are composed of a core of distinct offset units, up to several metres thick, covered by a blanket of firn and snow. The interfaces between the units of ice are often demarcated by thin sections of frozen caribou dung and fine sediment. Radiocarbon dates of dung extracted from ice cores have revealed a long history for these perennial patches, up to 4400 years BP. Ice patch growth is discontinuous and occurs intermittently. Extensive time gaps exist between the units of ice, indicating that summers of catastrophic melt can interrupt extended periods of net accumulation. The results of this work not only display the character of ice patch development, but also indicate the significant role that ice patches can play in reconstructing the paleoenvironmental conditions of an area.Récemment, on a déterminé que les névés permanents du subarctique de l’Ouest canadien constituent des sources d’artefacts et de spécimens biologiques préservés cryogéniquement. La formation, la composition et la constance de ces névés n’ont toujours pas été étudiées. Dans le cadre de l’étude des névés des Territoires du Nord-Ouest, on a recouru à des géoradars (GPR) et au carottage de la glace pour examiner la stratigraphie et la structure interne de deux névés. Les résultats indiquent que les névés sont composés d’un noyau d’unités distinctes et décalées, mesurant plusieurs mètres d’épaisseur et recouvertes d’une couverture de vieille neige et de neige. L’interface entre les unités de glace est souvent démarquée par de minces sections de déjections de caribou gelées et de sédiments fins. La datation au radiocarbone des déjections extraites des carottes de glace révèle que ces névés pérennes ont une longue histoire, remontant jusqu’à 4400 ans BP. L’amplification des névés est discontinue et se produit de manière intermittente. Des écarts de temps considérables existent entre les unités de glace, ce qui laisse entendre que des étés de fonte catastrophique peuvent interrompre les périodes prolongées d’accumulation nette. Les résultats de cette étude laissent non seulement entrevoir le caractère de la formation des névés, mais indiquent également le rôle important que les névés peuvent jouer dans la reconstruction des conditions paléoenvironnementales d’une région

The aerobraking space transfer vehicle

With the advent of the Space Station and the proposed Geosynchronous Operation Support Center (GeoShack) in the early 21st century, the need for a cost effective, reusable orbital transport vehicle has arisen. This transport vehicle will be used in conjunction with the Space Shuttle, the Space Station, and GeoShack. The vehicle will transfer mission crew and payloads between low earth and geosynchronous orbits with minimal cost. Recent technological advances in thermal protection systems such as those employed in the Space Shuttle have made it possible to incorporate and aerobrake on the transfer vehicle to further reduce transport costs. The research and final design configuration of the aerospace senior design team from VPISU, working in conjunction with NASA, are presented. The topic of aerobraking and focuses on the evolution of an Aerobraking Space Transfer Vehicle (ASTV), is addressed

Curvature contraction of convex hypersurfaces by nonsmooth speeds

We consider contraction of convex hypersurfaces by convex speeds, homogeneous of degree one in the principal curvatures, that are not necessarily smooth. We show how to approximate such a speed by a sequence of smooth speeds for which behaviour is well known. By obtaining speed and curvature pinching estimates for the flows by the approximating speeds, independent of the smoothing parameter, we may pass to the limit to deduce that the flow by the nonsmooth speed converges to a point in finite time that, under a suitable rescaling, is round in the C² sense, with the convergence being exponential.The research of the second author was supported by an Australian Postgraduate Award. The research of the first, third, fourth and fifth authors was supported by Discovery Project grant DP120100097 of the Australian Research Council

Ancient DNA Reveals Genetic Continuity in Mountain Woodland Caribou of the Mackenzie and Selwyn Mountains, Northwest Territories, Canada

We examine the mitochondrial genetic stability of mountain woodland caribou (Rangifer tarandus caribou) in the Mackenzie and Selwyn Mountains, Northwest Territories, over the last 4000 years. Unlike caribou populations in the Yukon, populations in the Northwest Territories show no evidence for mitochondrial genetic turnover during that period, which indicates that they were not adversely affected by the widespread deposition of the White River tephra around 1200 years ago. We detect moderate genetic differentiation between mountain woodland and barren-ground caribou in both territories, lending support to the current subspecies designations. In addition, we identify moderate genetic differentiation between Northwest Territories and western Yukon mountain woodland caribou, suggesting that there has been minimal mixing of matrilines between these herds.Nous examinons la stabilité génétique mitochondriale des caribous des bois des montagnes (Rangifer tarandus caribou) qui ont évolué dans les monts Mackenzie et dans la chaîne de Selwyn, Territoires du Nord-Ouest, ces 4 000 dernières années. Contrairement aux populations de caribou du Yukon, les populations de caribou des Territoires du Nord-Ouest ne montrent aucun signe de rotation génétique mitochondriale pendant cette période, ce qui indique qu’ils n’ont pas été affectés de manière défavorable par le dépôt à grande échelle du téphra de la rivière White, il y a environ 1 200 ans. Nous détectons une différentiation génétique modérée entre le caribou des bois des montagnes et le caribou de la toundra dans les deux territoires, ce qui vient appuyer les désignations actuelles de sous-espèces. Par ailleurs, nous avons dénoté une différenciation génétique modérée entre le caribou des bois des montagnes des Territoires du Nord-Ouest et celui de l’ouest du Yukon, ce qui laisse croire qu’il y aurait eu peu de mélanges matrilinéaires entre ces troupeaux