Effect of rapidly resorbable bone substitute materials on the temporal expression of the osteoblastic phenotype \u3cem\u3ein vitro\u3c/em\u3e

Ideally, bioactive ceramics for use in alveolar ridge augmentation should possess the ability to activate bone formation and, thus, cause the differentiation of osteoprogenitor cells into osteoblasts at their surfaces. Therefore, in order to evaluate the osteogenic potential of novel bone substitute materials, it is important to examine their effect on osteoblastic differentiation. This study examines the effect of rapidly resorbable calcium–alkali– orthophosphates on osteoblastic phenotype expression and compares this behavior to that of ß-tricalcium phosphate (TCP) and bioactive glass 45S5. Test materials were three materials (denominated GB14, GB9, GB9/25) with a crystalline phase Ca2KNa(PO4)2 and with a small amorphous portion containing either magnesium potassium phosphate (GB14) or silica phosphate (GB9 and GB9/25, which also contains Ca2P2O7); and a material with a novel crystalline phase Ca10[K/Na](PO4)7 (material denominated 352i). SaOS-2 human bone cells were grown on the substrata for 3, 7, 14, and 21 days, counted, and probed for an array of osteogenic markers. GB9 had the greatest stimulatory effect on osteoblastic proliferation and differentiation, suggesting that this material possesses the highest potency to enhance osteogenesis. GB14 and 352i supported osteoblast differentiation to the same or a higher degree than TCP, whereas, similar to bioactive glass 45S5, GB9/25 displayed a greater stimulatory effect on osteoblastic phenotype expression, indicating that GB9/25 is also an excellent material for promoting osteogenesis

Spider family Caponiidae

12 p. : ill. ; 26 cm. "August 28, 2009." Includes bibliographical references (p. 12).A new genus and species, Iraponia scutata, are established for the first members of the Caponiidae to be found in Iran. Males of this new genus, the second known from Asia, are unique in the family in having an extensive ventral abdominal scutum, and in having lost the posterior median pair of spinnerets. These caponiids have six eyes, a character shared only with some members of the New World genus Caponina.Published by the American Museum of Natural History, New york, NY

Bodies, technologies and action possibilities: when is an affordance?

Borrowed from ecological psychology, the concept of affordances is often said to offer the social study of technology a means of re-framing the question of what is, and what is not, ‘social’ about technological artefacts. The concept, many argue, enables us to chart a safe course between the perils of technological determinism and social constructivism. This article questions the sociological adequacy of the concept as conventionally deployed. Drawing on ethnographic work on the ways technological artefacts engage, and are engaged by, disabled bodies, we propose that the ‘affordances’ of technological objects are not reducible to their material constitution but are inextricably bound up with specific, historically situated modes of engagement and ways of life

Brignolia.

131 p. : ill. ; 26 cm. "Issued April 29, 2011."Males of the goblin spider genus Brignolia Dumitresco and Georgesco have palps that are heavily sclerotized, resembling those found in males of the genus Ischnothyreus Simon. Nevertheless, these palps have the dorsal depression ("fenestra") previously considered synapomorphic for the genus Opopaea Simon (plus its likely synonym Epectris Simon), and the female genitalia also correspond closely to those of Opopaea species, with the addition of a posterior tube. Brignolia males lack the inflated and subbasally connected palpal patella characteristic of Opopaea (plus Epectris), and Brignolia is therefore hypothesized to represent the sister group of those taxa. The generic names Lisna Saaristo and Aridella Saaristo, each based on a single species from the Seychelle Islands, are newly synonymized with Brignolia. The type species, B. cubana Dumitresco and Georgesco, has attained a pantropical distribution, and has at least three earlier names; Xestaspis parumpunctata Simon from Sierra Leone, Gamasomorpha perplexa Bryant from the Virgin Islands, and B. recondita (Chickering) from Panama are each placed as senior synonyms of B. cubana. Opopaea ambigua Simon, from Sri Lanka, is transferred to Brignolia. A total of 26 new species are described. Two are from the New World (B. dasysterna from Florida, and B. cobre from Florida and the West Indies), but most are from southern Asia and the Indopacific region: B. sinharaja and B. ratnapura from Sri Lanka, B. rothorum, B. cardamom, B. kumily, B. valparai, B. kaikatty, B. nilgiri, B. kodaik, B. jog, and B. karnataka from southern India, B. bengal, B. sukna, B. assam, and B. ankhu from northern India and Nepal, B. mapha, B. suthep, B. diablo, and B. chumphae from Thailand, B. schwendingeri from Vietnam, B. palawan from the Philippines, and B. gading, B. elongata, and B. kapit from Borneo

Impact of measurement backaction on nuclear spin qubits in silicon

Phosphorus donor nuclear spins in silicon couple weakly to the environment making them promising candidates for high-fidelity qubits. The state of a donor nuclear spin qubit can be manipulated and read out using its hyperfine interaction with the electron confined by the donor potential. Here we use a master equation-based approach to investigate how the backaction from this electron-mediated measurement affects the lifetimes of single and multi-donor qubits. We analyze this process as a function of electric and magnetic fields, and hyperfine interaction strength. Apart from single nuclear spin flips, we identify an additional measurement-related mechanism, the nuclear spin flip-flop, which is specific to multi-donor qubits. Although this flip-flop mechanism reduces qubit lifetimes, we show that it can be effectively suppressed by the hyperfine Stark shift. We show that using atomic precision donor placement and engineered Stark shift, we can minimize the measurement backaction in multi-donor qubits, achieving larger nuclear spin lifetimes than single donor qubits

Pelicinus.

43 p. : ill. (some col.) ; 26 cm.Although Pelicinus Simon and its type species P. marmoratus Simon were initially described from Saint Vincent in the Lesser Antilles, we hypothesize that Pelicinus is primarily an Old World genus, occurring natively in both southern Asia and Australasia. The type species has attained an anomalously pantropical distribution, and has been described at least eight times, in at least seven different genera; all those synonyms were based on island populations. Myrmopopaea jacobsoni Reimoser from Sumatra, Gamasomorpha minima Berland from the Phoenix Islands, Triaeris pusillus (Bryant) from the Virgin Islands, Scaphiella ula Suman from Hawaii, and P. mahei (Benoit) from the Seychelles are newly synonymized with P. marmoratus, and the species is newly recorded from the Bahama Islands, Brazil, Kenya, and the Marshall Islands. Myrmopopaea Reimoser and Harryoonops Makhan and Ezzatpanah are placed as junior synonyms of Pelicinus. The bulk of the species-level diversity of Pelicinus occurs in Australia. Here we treat only those members of the genus that occur outside that continent; 16 new species are described from Iran (P. sengleti), India (P. lachivala, P. madurai), Thailand (P. deelemanae, P. schwendingeri, P. sayam, P. khao), Laos (P. tham), Vietnam (P. duong), Malaysia (P. penang, P. johor), the Solomon Islands (P. churchillae), Fiji (P. raveni), and New Caledonia (P. monteithi, P. damieu, P. koghis)

Residents\u27 perceptions of smart energy metres

Smart metres are a form of expert system with performance features beyond energy‐consumption record keeping, to include monitoring, analysing, and estimating metre readings. Although smart metres have great capabilities, this technology is still in its infancy in many developing countries, and little is known about the kinds of risks associated with smart metres from residents\u27 perspectives. This research therefore aims to fill this gap by examining the influence of four different types of perceived risk on residents\u27 intentions to use smart metres in Jordan. By following a quantitative approach, 242 survey responses were tested by using structural equation modelling–partial least squares. The statistical results indicated that perceived security and technical risks have a significant and negative impact on residents\u27 intentions to use smart metres. However, perceived privacy and health risks, surprisingly, were found to have no significant negative influence on intention to use. Theoretical and practical implications are indicated, and directions of future research are subsequently specified

The Gas Content in Galactic Disks: Correlation with Kinematics

We consider the relationship between the total HI mass in late-type galaxies and the kinematic properties of their disks. The mass $M_HI$ for galaxies with a wide variety of properties, from dwarf dIrr galaxies with active star formation to giant low-brightness galaxies, is shown to correlate with the product $V_c R_0$ ($V_c$ is the rotational velocity, and $R_0$ is the radial photometric disks scale length), which characterizes the specific angular momentum of the disk. This relationship, along with the anticorrelation between the relative mass of HI in a galaxy and $V_c$, can be explained in terms of the previously made assumption that the gas density in the disks of most galaxies is maintained at a level close to the threshold (marginal) stability of a gaseous layer to local gravitational perturbations. In this case, the regulation mechanism of the star formation rate associated with the growth of local gravitational instability in the gaseous layer must play a crucial role in the evolution of the gas content in the galactic disk.Comment: revised version to appear in Astronomy Letters, 8 pages, 5 EPS figure

Quantum point contact on graphite surface

The conductance through a quantum point contact created by a sharp and hard metal tip on the graphite surface has features which to our knowledge have not been encountered so far in metal contacts or in nanowires. In this paper we first investigate these features which emerge from the strongly directional bonding and electronic structure of graphite, and provide a theoretical understanding for the electronic conduction through quantum point contacts. Our study involves the molecular-dynamics simulations to reveal the variation of interlayer distances and atomic structure at the proximity of the contact that evolves by the tip pressing toward the surface. The effects of the elastic deformation on the electronic structure, state density at the Fermi level, and crystal potential are analyzed by performing self-consistent-field pseudopotential calculations within the local-density approximation. It is found that the metallicity of graphite increases under the uniaxial compressive strain perpendicular to the basal plane. The quantum point contact is modeled by a constriction with a realistic potential. The conductance is calculated by representing the current transporting states in Laue representation, and the variation of conductance with the evolution of contact is explained by taking the characteristic features of graphite into account. It is shown that the sequential puncturing of the layers characterizes the conductance.Comment: LaTeX, 11 pages, 9 figures (included), to be published in Phys. Rev. B, tentatively scheduled for 15 September 1998 (Volume 58, Number 12