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Background Retinitis pigmentosa (RP) is a rare, progressive, and hereditary disorder that leads to the progressive loss of vision and visual field, and in some cases blindness. The specific relationship between RP and glaucoma has been debated for decades. Methods In this study, we examined a Han RP family with concomitant angle-closure glaucoma (ACG), performed an inductive analysis of their clinical features and assistant results, and applied whole-exome sequencing (WES) technology for a molecular diagnosis. Results A novel transversion mutation (c.626 T > A) was identified in the peripherin-2 (PRPH2) gene in the proband, resulting in the substitution of Valine to aspartic acid in codon 209. A full ophthalmic examination showed that the proband with the c.626 T > A mutation had a typical RP manifestation, with close angles; however, the proband’s elder brother, who lacked the novel mutation, had a normal fundus and open angles. Conclusion Our results extend the genetic mutation spectrum of PRPH2 in RP, and provide evidence to support a genetic correlation between RP and ACG.

Using first-principle calculations based on density functional theory, we investigate the strain and different edge terminations modulated electronic and magnetic properties of armchair AlN/SiC nanoribbons. The results show that the edge terminations Fe, Co, Cl can decrease or even eliminate the edge deformation of AlN/SiC nanoribbon. The magnetism of the nanoribbons is greatly adjusted by magnetic atoms Fe and Co, but not by Cl atoms. Apart from the nanoribbon with Cl terminations, the magnetism of the residual nanoribbons can be adjusted by increasing the compressed or stretched strain. The magnetic semiconductor nanoribbon with Co terminations becomes a magnetic half-metal system and then becomes a magnetic metal system, with the increase of the compressed strain. The magnetism of the nanoribbon with dangling bonds is attributed to the SiC edge and its nearest-neighbour C atoms, whereas the magnetism of the nanoribbon with Fe (or Co) terminations is mainly contributed by Fe (or Co) terminations.

Under the generalized gradient approximation (GGA), the structural and electronic properties are studied for both zigzag (ZAlNNRs) and armchair (AAlNNRs) AlN nanoribbons terminated with H atoms at both edges by using the first-principles projector-augmented wave (PAW) potential within the density function theory (DFT) framework. The results show that the Al–N, Al–C and Al–H bonds are ionic bonds while the C–C and C–H bonds are typical covalent bonds, and the N–C and N–H bonds have a degree covalent character. The systems of both perfect 7-ZAlNNR and perfect 7-AAlNNR with a single C-chain doped are still nonmagnetic semiconductors, and the C-chain reduces the band gap. The C-chain can change the band gap of 7-ZAlNNR from direct to indirect independent of the position of the C-chain, which is important in the practical application as light emitting devices. For N Z -ZAlNNR-C( n ) with N Z = 3, 5, 6, 10, the band gap decrease successively for C-chain position n from 2 to 3, 5, 6, 7 and 10, respectively. For N A -AAlNNR-C( n ) of arbitrary width N A , except N A -AAlNNR-C(1) and N A -AAlNNR-C( n = N A ) have a larger band gap, the band gap of the rest of the N A -AAlNNR-C( n ) are about 2.0 eV. Furthermore, the maximum band gap gradually decrease with the increase of the width N A . The C-chain substituting Al–N chain process is endothermic for both 7-ZAlNNR and 7-AAlNNR.

The electronic structure and magnetic properties of Hg2CuTi-type Mn2NiSn have been studied by performing the first-principle calculations. It is found that the phase transformation from the cubic to the tetragonal structure reduces the total energy, indicating that the martensitic phase is more stable and the phase transition from austenite to martensite may happen at low temperature for Hg2CuTi-type Mn2NiSn. Concerning the magnetism of Hg2CuTi-type Mn2NiSn, both austenitic and martensitic phases are suggested to be ferrimagnets. Furthermore, martensitic transformation decreases the magnetic moment per formula unit compared with austenitic phase. The results are helpful to accelerate the use of Mn2NiSn alloys in the series for magnetic shape memory applications.

Using first-principle calculations based on density functional theory, we investigate the electronic structures and magnetic properties of zigzag AlN/SiC nanoribbons. Bare N edge can cause the redistribution of the magnetic moment of the whole nanoribbon, whereas bare Si edge only has a certain effect on the magnetic moment of Si–C chain. The magnetic moment of the nanoribbon with bare Si and N edges is slightly larger than the summation of the magnetic moments of the nanoribbon with bare Si edge and nanoribbon with bare N edge. Bare N edge has a main contribution on the band gap of the corresponding nanoribbons.

The structural, magnetic and electronic properties of the perfect and defective La0.5Sr0.5MnO3 are investigated by performing the first-principle calculation. The negative value of formation energy implies the formation process of N atom substituting O atom in La0.5Sr0.5MnO3 are exothermic, indicating this structure could stably exist. Both the perfect and defective La0.5Sr0.5MnO3 are found to be half-metallic ferromagnets and potential in spintronic devices. For La0.5Sr0.5MnO3, the gap width of 2.902 eV is extremely wide. While the gap width decrease with existing the defect and the gap width decreases according to the order of the perfect, VO and DN. There are different mechanisms determining the band gaps of the perfect and defective La0.5Sr0.5MnO3.

PURPOSE To present and evaluate modified scleral tunnel in prevention of tube exposure following Ahmed valve implantation in refractory glaucoma. METHODS In the Affiliated Eye Hospital of Shandong University of Traditional Chinese Medicine, a retrospective study was conducted in 36 eyes of 34 patients who were diagnosed with refractory glaucoma and underwent Ahmed glaucoma valve implantation. In the surgery, the modified scleral tunnel was done to prevent tube exposure. RESULTS At the end of follow-up (mean 21.68±9.25 mo), there was no conjunctival tube exposure in all 36 eyes. The mean intraocular pressure was 18.3±6.79 mmHg, and 8 eyes needed 1 to 3 types of drugs to decrease intraocular pressure. CONCLUSIONS The modified scleral tunnel technique in Ahmed glaucoma valve implantation is able to prevent conjunctival tube exposure in the patients with refractory glaucoma.

First-principles calculations are performed to investigate the electronic and magnetic properties of armchair AlN/SiC heterostructure nanoribbons (A(AlN)x(SiC)11−xNRs). A(AlN)x(SiC)11−xNRs (x = 0, 3, 5, 7, 9 and 11) with H terminated at both edges are all semiconductors with direct band gaps, and a tunable band gap can be obtained via controlling the composition ratio of AlN/SiC nanoribbons. The unpassivated edge Al, N, Si or C atom can cause magnetic moments, which may open a way to design magnetic nanodevices based on AlN/SiC heterostructure nanoribbons. In additional, these systems with dangling bond are changed to magnetic semiconductors with indirect band gaps, the band gap change from direct to indirect is important in the practical application as light emitting devices. The net charge mainly accumulates at the bared atom, and a small part of contribution of magnetic moments can be attributed to the neighboring atoms with larger electronegativity than the bared atom.

First-principles calculations are performed to study the structural, electronic and magnetic properties of pure and C atom doped AlN nanoribbons with both zigzag edge (ZAlNNR) and armchair edge (AAlNNR). With the substitution of one N (Al) atom by a single C atom, a local expansion (a local contraction) takes place, and the C atom is preferred to substituting an edge N or Al atom in 7-ZAlNNR or 7-AAlNNR. Furthermore, by substituting C atom at different positions, the systems may turn into magnetic semiconductors or show a metallic character, which may open a way to design magnetic nanodevices based on AlNNR.

The effects of a single Fe-chain on the structural, electronic and magnetic properties of the H terminated zigzag AlN nanoribbons (ZAlNNRs) have been investigated systemically by using the first-principles methods. The results show that the valence charge density decreases for N, H, Fe and Al atom successively is related to their successively decreasing electronegativity. And no charge accumulated on Al atoms implies a significant charge transfer to N, Fe and H atoms from their nearest Al atom. In addition, the AlN nanoribbons change from nonmagnetic semiconductor to magnetic conductor after doping a single Fe chain, and the spin polarization and magnetic moment change suddenly after doping a single Fe-chain.

Under the generalized gradient approximation (GGA), the structural and electronic properties of armchair AlN nanoribbons with different edge terminations have been investigated by using the first-principles projector-augmented wave (PAW) potential within the density function theory (DFT) framework. AlNNR-F–F, AlNNR-H–F, AlNNR-H–H, AlNNR-F–Pd and AlNNR-H–Pd systems can be formed easily and exist steadily. H–H terminations have a slight effect on the charge distribution and the density of states of AlN nanoribbon, and considerably broaden the band gap of the AlN nanoribbon. The AlNNR-H–Pd system presents a metallic character and has the nearly same charge distribution as the AlNNR-Pd–Pd system which is instable.

Under the generalized gradient approximation (GGA), the electronic and magnetic properties of armchair SiC/AlN nanoribbons have been investigated by using the first-principles projector-augmented wave (PAW) potential within the density function theory (DFT) framework. The unpassivated SiC but not AlN edge can cause magnetic moments of the nanoribbons. The net up-spin charge mainly accumulates at C1, C2 and Si1 sites for ferromagnetic nanoribbons. The increasing concentration of Si–C chains has little effect on the magnetic properties of the nanoribbon, whereas the number of the dangling bonds caused by Si and C atoms strongly affects the magnetic of the system.

Underwater sensor network (UWSN) adopts acoustic communication with more energy-consumption and longer propagation-delay, which bring great challenges to protocol design. In this paper, we proposed level-based adaptive geo-routing (LB-AGR) protocol. LB-AGR divides traffics into four categories, and routes different types of traffic in accordance with different decisions. Packets upstream to the sink are forwarded unicast to the best next-hop instead of broadcasting to all neighbor nodes as in present UWSN routing protocols. LB-AGR defines an integrated forwarding factor for each candidate node based on available energy, density, location, and level-difference between neighbor nodes, which is used to determine the best next-hop among multiple qualified candidates. Through simulation experiments, we show the promising performance of LB-AGR.

The electronic and magnetic properties of zigzag AlN-SiC nanoribbons are investigated by using the first-principles calculations. The band structures reveal that all the investigated AlN-SiC systems are the magnetic semiconductors, the band gaps of which decrease with the increasing width of the ribbon. The majority spin density is mostly contributed by the edge C atoms with dangling bonds. The total magnetic moments increase with the increasing width of the ribbon and decrease with the increase of the strain. These studies are helpful to the potential applications of the AlN-SiC ribbon in spintronics.

The structural stabilities, electronic and magnetic properties of Mn atom adsorption on pure and C substituted BN sheet (CB–BN and CN–BN) are investigated using density function theory. The calculation showed that the Fermi level of CB–BN and CN–BN shifted up by 3 eV and −0.3 eV, respectively with a decreased band gap of 2.4 eV indicating that they can be used as n-type and p-type wide band gap semiconductors. C doping increases the interaction between Mn atom and BN sheet. Furthermore, among the three elements, C has the strongest ability to adsorb Mn atom, B comes the second. Mn/BN (or C doped BN) system presents strong magnetism which can be used as spin-electron device. The strong magnetism is induced by Mn-3d orbit. The strong hybridization between C-p orbit and Mn-d explains the firm interaction between Mn atom and BN sheet.

Under the generalized gradient approximation (GGA), the structural and electronic properties of armchair GaN nanoribbons with AlN edges have been investigated by using the first-principles projector-augmented wave (PAW) potential within the density function theory (DFT) framework. The results reflect that the band gaps of the armchair GaN nanoribbons (AGaNNRs) are vibrated with the increasing ribbon width. For Al, Ga, H and N atom, the successively increasing electronegativity of 3.04, 2.1, 1.81 and 1.61 causes the successive increase of the charge density. These results are very useful for the applications of the AGaNNRs.

Structural stabilities, electronic structures, and magnetic properties of Cu atom adsorption on pure, B(N)-doped and single-vacancy graphene have been studied using the first-principle method. It was found that the electronic property of graphene can be tuned by B or N doping. B-doped and N-doped graphene turned into a p-type and n-type semiconductor with a band gap of 0.2 eV, respectively. Total energy calculation results demonstrated the most stable site for the Cu atom adsorption on pure, B-doped and N-doped graphene is the top, bridge, and hollow site, respectively. B doping and vacancy both enhance the adsorption capacity for the Cu atom, while N doping weakens the capacity. Furthermore, B and N atoms do not induce magnetism in graphene, while the magnetic moment is induced when Cu is adsorbed on the graphene sheet, which is mainly caused by the unsaturated s-electrons of the Cu atom.

The structural stabilities, electronic, and magnetic properties of Ni dimers adsorption on pure and single-vacancy graphene were studied using a first-principle method. It was found that structures of the Ni dimer adsorbed on single-vacancy graphene are more stable than those structures of the Ni dimer adsorbed on pure graphene. Total energy calculation results demonstrated that for Ni dimer adsorption on single-vacancy graphene and pure graphene, the most stable structure is PV2 where the Ni dimer is positioned perpendicular to the vacancy site and PH1 where Ni dimer standing perpendicular to hollow site. Furthermore, it indicated covalent bond was formed between Ni atoms and their nearest C atoms, suggestive of chemisorption. The structures where Ni dimer lay horizontal to the pure graphene layer (H(T1–T3), H(B1–B2), H(B1–B3)) showed strong magnetism, while the structures of dimer-adsorption structures on single-vacancy graphene do not exhibit magnetism. The electronic origin of magnetic states was located on Ni atoms, specifically the d orbit. The Ni dimer, positioned parallel to the graphene plane, offers the possibility for the formation of Ni atom chain or wire on graphene, which might have potential nanoelectronic applications.

Under the generalized gradient approximation (GGA), the structural and electronic properties of coaxial nanocables of AlN nanowire core and SiC nanotube sheath have been investigated by using the first-principles projector-augmented wave (PAW) potential within the density function theory (DFT) framework. The combining processes of all three hybrid systems are exothermic and the most stable structure is AlNNW@(9,0) SiCNT system. The C 1 Al 1 and N 1 Si 1 ionic binding characters between the SiCNT and the AlNNW are disclosed. The AlNNW@(9,0) SiCNT system is extremely suitable for application in high-power, high-temperature and high-frequency electronics devices due to its broad energy gap.

Underwater sensor network (UWSN) adopts acoustic communication and is characterized by high delay, low bandwidth, high error rate, low energy-consumption requirement and sparse topology, which lead to conventional network protocols for terrestrial WSN or other wireless multi-hop networks are unable to satisfy the performance of UWSN. On the other hand, the limited resources of energy, CPU and memory cause that the protocol stack running on the sensor node shouldn’t be much complicated. The paper proposes a novel, green network protocol architecture model tailored for UWSN, referred to as Micro-ANP, which is three layered structure including application, network transport, and physical layer. Furthermore, basing on Micro-ANP we realize the packet size optimization of UWSN through Matlab simulation. Micro-ANP protocol architecture and packet size optimization improve the energy efficiency of UWSN, prolong the network lifetime and achieve green network while meeting the requirement of QoS with the constraints of limited resource.

To evaluate the safety and efficacy of Ex-PRESS (R50) implantation combined with phacoemulsification in primary angle-closure glaucoma (PACG) patients with cataract. Twenty-four eyes of 24 patients with unregulated PACG underwent combined cataract and glaucoma surgery. After phacoemulsification and intraocular lens implantation, the Ex-PRESS (R-50) was inserted into the anterior chamber under a scleral flap. The intraocular pressure (IOP), best corrected visual acuity (BCVA), number of medications, and complications were recorded preoperatively as well as postoperatively on day 7 and at 1, 3, 6, and 12 months. The mean follow-up was 16.4 ± 2.5 months (range 14–21 months) and the mean age of the patients was 64.7 ± 6.8 years (range 56–78 years). The mean IOP was 20.4 ± 5.4 mm Hg preoperatively and decreased to 10.2 ± 2.8, 13.1 ± 2.7, 14.9 ± 4.1, 14.3 ± 3.9, and 14.0 ± 3.6 mm Hg on day 7 and at 1, 3, 6, and 12 months after surgery (all P

The magnetic ordering and relative structural stability (phase diagram) of La2/3Sr1/3MnO3/SrTiO3 (LSMO/STO) (001) interfaces are considered by performing generalized gradient approximation plus on-site Coulomb correction calculations. A potential antiferromagnetic alignment between the interface layer and bulk is conjectured for the b-type LSMO/STO (001) interface where the atomic-layer stacking near interface is LaOMnO2LaOMnO2SrOMnO2SrOTiO2 (SrO termination). This is in qualitative agreement with the fact that suppression of ferromagnetism at the SrO-terminated (001) interface is found at some experiments. The small magnetic exchange energies, for the SrO-terminated LSMO/STO (001) interfaces, suggest that Mn spins at the interface are likely to reverse as the temperature changes. Hence, possible magnetic reconstructions will be expected to occur at the SrO-terminated (001) interfaces when temperature increases. Under thermodynamic equilibrium, the calculated phase diagrams show that, with the exception of the c-type (001) interface where the atomic-layer stacking near interface is La2/3Sr1/3OMnO2SrOTiO2 (SrO termination), all other considered LSMO/STO (001) interfaces may be stabilized in the proper conditions. The spin-resolved density of states shows that high spin-transport behaviors could be achieved at the ferromagnetic TiO2-terminated (001) interfaces. The results of the calculations can compare favorably with the experimental results for the LSMO/STO (001) junctions.

Under the generalized gradient approximation (GGA), the stabilities and electronic properties of semiconductor AlN nanostructures have been investigated by using the first-principles projector-augmented wave (PAW) potential within the density function theory (DFT) framework. The single-walled faceted AlNNTs present an obvious structural modification. The larger the diameter, the more stable the nanowire, and the wires without internal surfaces are more stable than the multiwalled tubes or the SWNT. Therefore, the large-size nanowires are easier to be synthesized than the corresponding multiwalled tubes or single-walled nanotube in experiment. The dangling bonds of surface atoms cause the “localized edge-induced states”. These two nanostructures C and F are still wide band gap semiconductors accompanied by a few surface states located in the band gap of bulk AlN and thus extremely suitable for application in flexible pulse wave sensors, nanomechanical resonators and light-emitting diodes.

The quantitative and temporal-evolutional advantages of the microscopic phase field are used to study the lattice defects of the L12–Ni3Al(γ′) phase in a ternary Ni–Al–V system. The temporal evolutional process of the occupancy of each individual atom conforms to classical nucleation processes, where the occupancy is constant at the incubation period, and then fluctuates up or down during segregation and equilibrium at the coarsening period. The α sublattice of the L12 structure is almost completely occupied by regular NiNi with a small amount of antisite defect AlNi and the substitutional defect VNi at the equilibrium state. By sharp contrast, the β sublattice is predominantly occupied by regular AlAl, as well as the non-negligible antisite defect NiAl and substitutional defect VAl. Regular atoms have a negative correlation with temperature; hence, the defects are positive. By comparison, the β sublattice, which accommodates most of the defects in Ni3Al, is more sensitive to temperature than the α sublattice. The results are generally in line with comparisons reported by other scientists.

The phase-field crystal (PFC) model is employed to study the shape transition of strained islands in heteroepitaxy on vicinal substrates. The influences of both substrate vicinal angles β and the lattice mismatch ξ are discussed. The increase of substrate vicinal angles is found to be capable of significantly changing the surface nanostructures of epitaxial films. The surface morphology of films undergoes a series of transitions that include Stranski-Krastonov (SK) islands, the couple growth of islands and the step flow as well as the formation of step bunching. In addition, the larger ξ indicates an increased strained island density after coarsening, and results in the incoherent growth of strained islands with the creation of misfit dislocations. Coarsening, coalescence and faceting of strained islands are also observed. Some facets in the shape transition of strained islands are found to be stable and can be determined by β and crystal symmetry of the film.

Under the generalized gradient approximation (GGA), the structural and electronic properties of conducting Cu8 nanowires encapsulated in semiconducting zigzag carbon nanotubes (CNT) have been investigated by using the first-principles projector-augmented wave (PAW) potential within the density function theory (DFT) framework. Among these three Cu8 wire-encapsulated C cables, (11,0) and (13,0) nanocables are formed endothermically, (14,0) nanocable is formed exothermically. Consequently, it is expected that the thicker Cu wire would be pulled spontaneously into wider nanotubes by forces amounting to a fraction of a nanonewton. The high electrical transport behaviors of the Cu8-encapsulated C cables coming only from the Cu8 nanowire indicate the Cu8-encapsulated C cables can be applicable for the ultralarge-scale integration (ULSI) circuits.

Under the generalized gradient approximation (GGA), the energy and electronic structure of a single copper atomic chain bound in an armchair (6, 6) or zigzag (10, 0) carbon nanotube (CNT) have been investigated by using the first-principles projector-augmented wave (PAW) potential within the density function theory (DFT) framework. The results show that both CNTs are nearly ideal to bind a single Cu atomic chain, especially on their center axis, although a very weak interaction still exits between the components of the combined systems. The accumulated charges between components of the combined system indicate Cu-CNT bonds may be regarded as very weakly covalent and the depleted charge from the Cu atomic chain has a 3d electron character. The restriction of the CNT makes the highest peak of the Cu atomic chain slightly shift towards the lower energy region, in reverse the strong metallic character of the Cu atomic chain also enhances the metallic character of the two combined systems. The appearance of a new peak near the Fermi level in the more concentrated Cu chain and consequently in the corresponding combined system, indicates their potential utilization in future nanoelectronics.

Under the generalized gradient approximation, the relaxed structures and electronic properties have been investigated for Au nanowires with cross sections of 3 x 3, 5 x 5, 7 x 7, 9 x 9, and 11 x 11 atom layers using the first-principles projector-augmented wave potential within the density functional theory. For all five-sized nanowires, the relaxed structures still have tetragonal symmetry and show a "round corner" phenomenon. The vanishing of the neighbor atoms outside the nanowire after being cleaved from bulk crystal not only causes the structure relaxation above but also affects the electronic properties in the following three aspects. (1) The total charges of the surface and near surface atoms are reduced. (2) The enhanced interactions appear between the surface atoms as well as the surface atoms and their first nearest neighbor atoms; we term this phenomenon the "skin effect", which enhances the mechanical and the electronic transport properties of the nanowire compared to bulk. (3) The farther the atoms are from the central axis of the nanowires, the more the electrons fall in the higher energy region of the occupancy state due to the lower coordination number and thus fewer restrictions. In fact, the conclusions drawn here are applicable to not only the nanowires but also the other surface cases, such as nanobelts, nanotubes, nanocables, clusters, thin films, and so on.

The electronic and magnetic properties of the three types of ferromagnetic nanowires (FN4’s), Fe4, Co4, and Ni4, encapsulated in boron nitride nanotubes (BNNTs) have been investigated systematically using the first-principles projector-augmented wave potential within the density functional theory under the generalized gradient approximation. We find that all three types of the FN4 encapsulated into the narrower (6,6) BNNT are endothermic, whereas if they are encapsulated into the broader (8,8) BNNT, they are exothermic. Both the spin polarization and the magnetic moment of the FN4@(8,8) systems are larger than those of the FN4@(6,6) systems due to weaker restriction of the broader (8,8) BNNT, but those of these two combined systems are smaller than those of the corresponding freestanding FN4. The spin polarization of the Co4@(8,8) system is larger than that of either the Fe4@(8,8) system or the Ni4@(8,8) system, which means that the Co4@(8,8) system can be used as a spin valve in spin-dependent transport ...

The paper analyzes the security of conventional network access authentication technology and provides a novel IP address pair based short signature technology which strengthens the security of authentication and control. Conforming to TNC architecture, the paper extends the endpoint access domination to MPLS backbone by IP address pair based short signature technology and depicts a new trustworthy network access scheme and realizes it on Network Processor. The scheme enriches the integrity measure of security client and administrator's security policy with ARP virus, fraud DHCP server, address spoofing of IP and MAC, thus enhances the safety and initiative defense ability of enterprise and public networks, and reduces the cost of enterprise for security deployments greatly while achieving the SP's excellent Return-on-Investment.

We modify the anisotropic phase-field crystal model (APFC), and present a semi-implicit spectral method to numerically solve the dynamic equation of the APFC model. The process results in the acceleration of computations by orders of magnitude relative to the conventional explicit finite-difference scheme, thereby, allowing us to work on a large system and for a long time. The faceting transitions introduced by the increasing anisotropy in crystal growth are then discussed. In particular, we investigate the morphological evolution in heteroepitaxial growth of our model. A new formation mechanism of misfit dislocations caused by vacancy trapping is found. The regular array of misfit dislocations produces a small-angle grain boundary under the right conditions, and it could significantly change the growth orientation of epitaxial layers.