[Analysis of the cognitive effects of monocular blindness and related influencing factors].

Objective: To investigate the cognitive effects of monocular blindness and related influencing factors. Methods: A cross-sectional study was conducted. The patients with monocular blindness (the age of onset <16 years) were enrolled from Beijing Tongren Eye Center, Beijing Tongren Hospital between January 2018 and June 2020. The Montreal cognitive assessment (MoCA) scale was applied to assess seven cognitive domains including visuospatial and executive function, naming, attention, etc. Based on MoCA scores, all the patients were classified into two groups: normal cognitive functions and cognitive impairment. Spearman's correlation was used to perform the single factor analysis of the influencing factors of cognitive functions. Multivariate linear regression analyses were applied to identify the independent influencing risk factors. Results: A total of 45 patients with monocular blindness were enrolled. There were 25 males and 20 females, with age at testing being (27±10) years.The incidence of cognitive impairment in 45 patients was 60.0% (27/45). The abnormal items ranking from a high to low rate were language (95.6%, 43 cases), delayed recall (75.6%, 34 cases), visuospatial and executive function (60.0%, 27 cases), abstract (44.4%, 20 cases), attention (35.6%, 16 cases), naming (20.0%, 9 cases), and orientation (0%). There were statistically significant differences (all P<0.05) in total score (21.9±3.3 vs. 27.4±1.4), visuospatial and executive function (3.2±1.7 vs. 4.6±0.7), naming (2.7±0.6 vs. 2.9±0.2), attention (5.3±1.0 vs. 5.8±0.4), language (1.1±0.8 vs. 1.8±0.8), abstract (1.1±0.8 vs. 1.8±0.5) and delayed recall (2.3±1.3 vs. 4.4±0.8) between two groups of patients with and without cognitive impairment. Spearman's correlation analysis showed visuospatial and executive functions, attention, abstract and MoCA total score were positively correlated with education years (correlation coefficients being 0.355, 0.424, 0.434 and 0.370, respectively; all P<0.05). Multiple linear regression showed that duration of blindness was correlated with naming (ß=-0.325), and years of education correlated with attention (ß=0.472), abstract ability (ß=0.441) and MoCA total score (ß=0.390) (all P<0.05). Conclusions: Monocular blindness may affect language, delayed memory and visuospatial executive functions. The duration of blindness is an independent risk factor, and higher education is a protective factor of the cognitive impairment.

[Ultrasonic manifestations and axis length of blind microphthalmia].

Objective: To discuss the ultrasonic manifestations of blind microphthalmia, and to explore the correlation between axis length and complicity of intraocular structure of blind microphthalmia. Methods: Retrospective case series study. The data of ultrasonic imaging and axis length of 162 patients (162 eyes) with blind microphthalmia diagnosed in Tongren Eye Center, Beijing Tongren Hospital from July 2013 to July 2018 were collected. According to the degree of internal structure disorder, all affected eyes were divided into groups of the normal, the abnormal and the indistinguishable. The binocular axial length in these patients were compared. The relationship between the axial length and the age of the patients, and the structural changes of the blind microphthalmia with a basic structure were analyzed. Statistical methods were mainly performed by paired t-test, one-way linear regression analysis and one-way analysis of variance. Results: The disease was unilateral in all the 162 patients. The age ranged from 1 month to 58 years old. And 139 cases (85.80%) were under 12 years old. There were 90 males and 72 females. The mean axial length of the affected eyes (162 eyes) was (13.17±3.77) mm, while the mean axial length of the control eyes (162 eyes) was (21.85±2.01) mm. There was significantly statistical difference in the ocular size between them (t=-27.369; P<0.01). There was no significant correlation between the axial length of the affected eye and age in patients with unilateral blind microphthalmia (r=0.027; P>0.05), while there was a significant correlation between the axial length of the control eye and age (r=0.590; P<0.01). The axial length of the groups of the normal (14 eyes), the abnormal (91 eyes) and the indistinguishable (57 eyes) was (17.80±2.19) mm, (14.81±2.92) mm and (10.05±2.46) mm, respectively, and the difference was statistically significant (F=72.800; P<0.01), and there was also significant difference between the two groups (all P<0.01). Ocular ultrasonic imaging showed that 105 eyes (64.81%) had a basic ocular structure, 83 eyes (51.23%) had retinal detachment, 15 eyes (9.26%) had bulbar ossification, and 10 eyes (6.17%) had optic disc abnormality. Conclusions: Blind microphthalmia mostly has a basic ocular structure and is often associated with retinal detachment. The axial length of the affected eye is correlated with the degree of intraocular structural disorder. (Chin J Ophthalmol, 2021, 57: 825-829).

Intrinsical localization of both topological (anti-kink) envelope and gray (black) gap solitons of the condensed bosons in deep optical lattices.

By developing quasi-discrete multiple-scale method combined with tight-binding approximation, a novel quadratic Riccati differential equation is first derived for the soliton dynamics of the condensed bosons trapped in the optical lattices. For a lack of exact solutions, the trial solutions of the Riccati equation have been analytically explored for the condensed bosons with various scattering length as. When the lattice depth is rather shallow, the results of sub-fundamental gap solitons are in qualitative agreement with the experimental observation. For the deeper lattice potentials, we predict that in the case of as>0, some novel intrinsically localized modes of symmetrical envelope, topological (kink) envelope, and anti-kink envelope solitons can be observed within the bandgap in the system, of which the amplitude increases with the increasing lattice spacing and (or) depth. In the case of as<0, the bandgap brings out intrinsically localized gray or black soliton. This well provides experimental protocols to realize transformation between the gray and black solitons by reducing light intensity of the laser beams forming optical lattice.

[Ocular manifestations and surgical treatment of the linear nevus sebaceous syndrome].

Objective: To report the clinical and pathological features and surgical treatment of the linear nevus sebaceous syndrome. Methods: It was a retrospective case series study. The clinical records of 11 patients (14 eyes) who were diagnosed as linear nevus sebaceous syndrome between April 2009 and February 2018 at Beijing Tongren Hospital were analyzed. Data collected included sex, age, clinical manifestations, disease site, pathological features, surgical treatment and therapeutic effects. Results: There were six males and five females, aged 6 months to 7 years (mean, 2.8 years). The nevus sebaceous was located at the head (9 patients), face (5 patients) and neck (3 patients). The most common ocular manifestations were blepharocoloboma (13 eyes) and external ocular mass (9 eyes). Surgical treatment was performed in 9 patients (11 eyes), including lid reconstruction in all these eyes, corneal and conjunctival mass resection in four patients (4 eyes), eyelid tumor resection in 5 patients (5 eyes), and symblepharon separation and conjunctival sac reconstruction in 3 patients (5 eyes). Pathological examinations of the external ocular, corneal and conjunctival masses (6 eyes) confirmed the diagnosis of complex choristoma. All operated patients had improved appearance. Conclusions: Linear nevus sebaceous syndrome has characteristic cutaneous lesions and ocular manifestations. Histopathologically, all epibulbar lesions prove to be complex choristomas. The appearance of patients with linear nevus sebaceous syndrome can be significantly improved by oculoplastic surgery. (Chin J Ophthalmol, 2020, 56: 846-852).

[Clinical histopathologic characteristics of lacrimal glands in lacrimal gland prolapse with blepharochalasis].

Objective: To analyze the clinical histopathologic characteristics of lacrimal glands and possible mechanisms of lacrimal gland prolapse in blepharochalasis (BC). Methods: A case-controlled study of 23 consecutive patients with prolapse of lacrimal glands in BC was performed. All samples were obtained during surgery from the Department of Ophthalmology, Beijing Tongren Hospital, Capital Medical University between January 2009 and December 2016. The lacrimal tissue included prolapsed lacrimal glands (30 samples) and controls from the donors in the eye bank of Beijing Tongren Hospital, Capital Medical University (8 samples). Hematoxylin-eosin staining, special staining, immunohistochemistry and colloidal gold-labeled pre-embedded indirect immunogold electron microscopy (Gold-IIEM) were performed to analyze the histopathologic characteristics of the samples. The nonparametric Wilcoxon signed-ranks test was carried out for statistical analysis. Results: Among the 23 patients with lacrimal gland prolapse in BC, there were 3 males and 20 females. The mean age of morbidity was 11 years old (7-16 years). In the 8 normal control cases, 3 males and 5 females were included. The mean age was 15 years (10-20 years). In the 30 prolapsed lacrimal gland samples, hematoxylin-eosin staining showed enlargement of glandular lumina accompanied by inflammatory infiltrates of interstitial tissue in 2 samples. Marked loosening of collagen fibers of the obtainable lacrimal fascia was observed. The results on immunohistochemical staining demonstrated an increased level of immunocytes in the 30 prolapsed lacrimal gland samples, including IgA (+++, ++, +, -; 12, 11, 4, 3 vs. 0, 0, 1, 7; Z=-3.892), CD3(+)T cells (+++, ++, +, -; 2, 19, 7, 2 vs. 0, 0, 1, 7; Z=-4.168), matrix metalloproteinase (MMP)-3 (+++, ++, +, -; 0, 0, 11, 19 vs. 0, 0, 0, 8; Z=-2.005) and MMP-9 (+++, ++, +, -; 14, 14, 0, 2 vs. 0, 0, 0, 8; Z=-4.552) (all P<0.05). IgG, IgM, CD20 and C1-inhibitor were either absent or expressed at background level in the 30 prolapsed lacrimal gland samples (all P>0.05). Gold-IIEM showed zymogon granules in lacrimal glands were out of shape. MMP-3 and MMP-9 colloidal gold particles existed on the zymogon granules, and MMP-3 colloidal gold particles also existed on the surface of lacrimal gland epithelial cells. Conclusions: The histopathological changes in the lacrimal glands of lacrimal gland prolapse with BC include inflammatory infiltration, elastic fiber degeneration, marked loosening of the supporting fascia tissue, and an increased level of immunocytes, including IgA, CD3(+)T cells, MMP-3 and MMP-9. The results suggest that lacrimal gland prolapse with BC may result in the immuno-pathogenetic mechanisms with the involvement of cell-mediated immune responses. (Chin J Ophthalmol, 2020, 56: 205-210).

[Clinical features and surgical management of orbitotemporal neurofibromatosis].

Objective: To report the clinical features and surgical treatment of orbitotemporal neurofibromatosis. Methods: It was a retrospective case series study. The clinical records of 24 patients who were treated for orbitotemporal neurofibromatosis between April 2007 and July 2017 at Beijing Tongren Hospital, Capital Medical University were analyzed. Data collected included sex, age, laterality, periorbital deformities, surgical treatment, follow-up time, complication and recurrence. Results: Sixteen males and 8 females were included. Age at surgery was (15±7) years (4-30 years). All patients were unilaterally involved. Twenty-three patients (96%) had upper lid involvement and ptosis. Nine patients (38%) had lower lid involvement. Fourteen patients (58%) had lateral canthal disinsertion. Three patients (13%) had brow involvement, 10 patients (42%) had conjunctival involvement and 2 patients (8%) had lacrimal gland infiltration. All patients had tumor debulking procedure. Twenty-two patients (92%) had correction of ptosis. Fourteen patients (58%) required lid reconstruction and lateral canthus reattachment surgery. Three patients (13%) had correction of brow ptosis.One patient (4%) had skull and orbit reconstruction. The median follow-up time was 3.5 (1.0-10.0) years. All patients had improved appearance. Ptosis recurred in 6 patients, but were corrected with surgery. On the last follow-up, 7 patients were free of ptosis. In 14 patients, mild ptosis was noted, but the upper lid did not cover the pupil. In 2 patients the pupil was half covered. Only in 1 patient who had not received ptosis correction surgery the pupil was covered completely. Conclusions: The periorbital deformities of orbitotemporal neurofibromatosis include upper eyelid infiltration with ptosis, lateral canthal disinsertion and infiltration of lower eyelid, brow, conjunctiva and lacrimal gland. The appearance of patients with orbitotemporal neurofibromatosis can be significantly improved through oculoplastic surgery. (Chin J Ophthalmol, 2019, 55: 828-833).

[Autogenic facia lata suspension for correction of paralytic ectropion].

Objective: To evaluate the outcome of autogenic facia lata suspension in the treatment of paralytic ectropion. Methods: It was a retrospective case series study. The clinical records of 21 patients (21 eyes) who were treated for paralytic ectropion with autogenic facia lata suspension between January 2015 and September 2017 at Beijing Tongren Hospital were analyzed. In the 21 patients, 7 were male and 14 were female. The range of age was 20-74 years and the mean age was (61±14) years. All of the participants received facia lata suspension for the correction of ectropion. Some of the patients also received associated wedge resection of the tarsus or lateral tarsal strip procedure. The anterior lamella was reconstructed with local flaps in some patients. The preoperative and postoperative degree of ectropion was measured. Paired sample t test was used to compare the preoperative and postoperative data. Results: Postoperative follow up for patient was conducted for 6-38 months. Residual lagophthalmos of 3 mm or more were present in 3 cases. Mild lower eyelid ectropion recurred in 1 patient one year after surgery. The rest cases achieved satisfactory aesthetic outcomes. No complication in the donor site was observed. The preoperative scleral show was (3.02±1.31) mm, and the postoperative data was (-0.05±0.72) mm. The preoperative margin reflex distance 2(MRD2) was (8.83±1.77) mm, and the postoperative MRD2 was (5.43±0.78) mm. The preoperative lagophthalmos was (6.17±1.91) mm, and the postoperative data was (1.98±1.09) mm. The differences between the preoperative and postoperative data were significant (t=13.530, P=0.000;t=11.913, P=0.000; t=11.882, P=0.000). Conclusion: Autogenic facia lata suspension is an effective method for the correction of paralytic ectropion, with good aesthetic outcome, low recurrence rate and few complications. (Chin J Ophthalmol, 2018, 54: 496-501).

[Etiological and drug sensitivity analysis of lacrimal canaliculitis].

Objective: To analyze the etiology and drug sensitivity of lacrimal canaliculitis. Methods: Retrospective study of case series. The general information, culture results and drug sensitivity results of 52 patients (including 10 males and 42 females with an average age of 60.3 years) clinically diagnosed with lacrimal canaliculitis during 2011 and 2016 at Beijing Tongren Hospital of Capital Medical University have been analyzed. The enumeration data have been tested with Chi-square method. Results: The positive rate of bacterial culture was 78.8%, and the fungal culture tests of all cases showed negative results. Sixty strains of bacteria were isolated from 41 patients whose bacterial culture tests showed positive results, Gram-positive bacteria have been confirmed as the main among the isolated bacteria with Streptococcus (18.3%), Propionibacterium (18.3%), and Streptococcus (15.0%) identified as the three common genera. Thirteen cases (25.0%, all the 13 patients were female) involved with mixed infection, 13.3% (8/60) of the isolated strains were multi-drug resistant bacteria. The drug sensitive rate of the bacteria to fluoroquinolones antibiotics(79.3%, 230/290) was higher than that to cephalosporins(62.1%, 36/58) and aminoglycoside antibiotics(56.3%, 98/174), and such differences are of statistical significance (χ(2)=7.977, 27.738, P<0.05). Except for the fact that gram-positive bacteria are mostly sensitive to vancomycin, the sensitive rate of the bacteria to gatifloxacin was the highest and that to tobramycin was the lowest. Conclusion: Lacrimal canaliculitis tend to affect women and elderly patients. Staphylococcus, Propionibacterium, and Streptococcus are the three most common genera. Gatifloxacin may be the preferred antibiotic. Antibiotics combination therapy should be applied for multi-drug resistant bacteria. (Chin J Ophthalmol, 2018, 54: 111-114).

[Value of CT in evaluating the risk of benign and malignant thyroid nodules].

Objective: To evaluate the value of CT in the risk assessment of thyroid benign nodules (BN) and malignant nodules (MN). Methods: The CT signs of 461 pieces of MN in 447 cases and 548 pieces of BN in 484 cases were retrospectively analyzed, the diagnoses were confirmed by histology, including nodular morphology, cookie bite sign, microcalcification, enhanced range narrow/blurred, cystic changes and enhanced.The signs of CT were analyzed by univariate and multivariate regression analysis.The positive CT signs were calculated to assess sensitivity and specificity in the diagnosis of BN and MN. Results: Univariate and multivariate analysis showed that irregular nodular morphology (χ(2)=509.263, P<0.001, OR=5.297), cookie bite sign (χ(2)=504.619, P<0.001, OR=3.467), microcalcification (χ(2)=97.793, P<0.001, OR=1.730), enhanced range reduction/blur (χ(2)=361.967, P<0.001, OR=5.729) were more common in MN.Cysts changes (χ(2)=223.208, P<0.001, OR=7.537) and enhancement signs (χ(2)=65.983, P<0.001, OR=10.782) were more common in BN.The sensitivity and specificity of irregular nodular morphology in the diagnosis of MN were 80.5% and 90%, those in cookie bite sign were 74.2% and 94.3%, microcalcification were 35.6% and 90.1%, enhanced range reduction/blur were 80.7% and 79.4%.The sensitivity and specificity of capsule-based and high-enhanced BN diagnosis were 42.2% and 98.1%, 19.0% and 97.4%, respectively. Conclusions: Irregular shape, cookie bite sign, microcalcification and enhanced range of narrowing/blur are significant CT signs in the assessment of MN, and cystic changes and enhancement are significant CT signs in the evaluation of BN.The diagnostic efficiency of various CT signs varies greatly, and combination of multiple CT signs can improve the diagnostic efficiency.

The charge and spin transport properties in hexagonal silicene nanorings.

Based on the tight-binding model, charge and spin transport properties of hexagonal silicene rings are investigated within the nonequilibrium Green's function technique. The effects of external electric, magnetic and exchange fields are taken into account. The calculated results reveal that the hexagonal silicene nanorings act as a controllable spin filter. The near-perfect spin polarization can be achieved by adjusting the electric, magnetic and exchange fields. The calculated results offer new possibilities for silicene ring based spin nanodevices.

[Developing and application of an autoverification system for clinical chemistry and immunology test results].

Objective: To develop and validate an autoverification system for biochemistry and immunology test results for application in routine work. Methods: Algorithms was designed and translated into the laboratory information system. Parameters including verify limit, delta check, logic relation between tests was set up in the system. Verification rate of every test and the causes of fails were analyzed, according to which the system and parameters were modified. The autoverified reports were evaluated by chief technicians. Only when all of the autoverified results pass the evaluation, the system applied for routine work of releasing the results. Autoverification rate and turnaround time(TAT) were calculated for evaluation of the efficiency of the system. Results: A brand new autoverification system was developed and applied for routine work. The autoverification rate for each single test was 91.1%-96.6%. The autoverification rate for reports was 74%. With the autoverification system, the media of TAT reduced from 111.6(53.9-270.7) min to 87.2(45.4-202.4) min, whereas the time from instrument finishing analysis to releasing the reports reduced from 18.6(1.0-99.3) min to 0.1(0-58.3)min. The number of staff specified for results validation reduced from three to one. Conclusions: The newly developed system can be used for autoverification of biochemistry and immunology test results. The autoverification system can greatly reduce TAT and raise working efficiency. It's essential to employ carefully designed algorithm, appropriate parameters and comprehensive evaluation when developing a new autoverification system.

[Effects and related mechanism of quercetin on thrombin-induced proliferation and migration of rat vascular smooth muscle cells].

OBJECTIVE: To investigate the effects and related mechanism of quercetin on thrombin-induced proliferation and migration of rat vascular smooth muscle cells(VSMCs). METHODS: Third to fifth generation VSMCs were divided into three groups, including control group (with PBS on the base of medium DMEM), thrombin group (with 1 U/ml thrombin on the base of medium DMEM) and quercetin group (treated with 100 µmol/L quercetin before 1 U/ml thrombin on the base of medium DMEM). The proliferation and migration capacitities were tested by CCK-8 kit and transwell chamber, respectively. The protein level of phospho-extracellular signal regulated kinase 1/2 and phosphor-p38 were measured by Western blot. RESULTS: (1) According to the CCK-8 results, optical density value was significantly higher in thrombin group than that of control group(2.59±0.16 vs. 1.97±0.18, P<0.01), which could be significantly attenuated by pretreatment with quercetin(2.13±0.19, P<0.01), and there was no significant difference between quercetin group and control group(P>0.05). (2) The transwell results showed that the migrated VSMCs were significantly higher in thrombin group than in control group (1 337±162 vs. 99±26, P<0.01), which could be significantly reduced by pretreatment with quercetin (926±111, P<0.05), but still significantly higher than control group (P<0.01). (3) The protein expressions of phospho-extracellular signal regulated kinase 1/2 and phosphor-p38 were significantly upregulated in thrombin group compared to control group (both P<0.05), which could be significantly downregulated by pretreatment with quercetin (P<0.05). CONCLUSION: Quercetin can effectively attenuate thrombin-induced vascular smooth muscle cells proliferation and migration, possibly through inhibiting the phosphorylation of extracellular signal regulated kinase 1/2 and p38 pathway.

Non-covalent doping of graphitic carbon nitride with ultrathin graphene oxide and molybdenum disulfide nanosheets: an effective binary heterojunction photocatalyst under visible light irradiation.

A proof of concept integrating binary p-n heterojunctions into a semiconductor hybrid photocatalyst is demonstrated by non-covalent doping of graphite-like carbon nitride (g-C3N4) with ultrathin GO and MoS2 nanosheets using a facile sonochemical method. In this unique ternary hybrid, the layered MoS2 and GO nanosheets with a large surface area enhance light absorption to generate more photoelectrons. On account of the coupling between MoS2 and GO with g-C3N4, the ternary hybrid possesses binary p-n heterojunctions at the g-C3N4/MoS2 and g-C3N4/GO interfaces. The space charge layers created by the p-n heterojunctions not only enhance photogeneration, but also promote charge separation and transfer of electron-hole pairs. In addition, the ultrathin MoS2 and GO with high mobility act as electron mediators to facilitate separation of photogenerated electron-hole pairs at each p-n heterojunction. As a result, the ternary hybrid photocatalyst exhibits improved photoelectrochemical and photocatalytic activity under visible light irradiation compared to other reference materials. The results provide new insights into the large-scale production of semiconductor photocatalysts.

Giant orbital paramagnetism in toroidal carbon nanopeapods.

The electronic structure and the magnetic response of toroidal carbon nanopeapods (TCNPs) are investigated within the sp(3) tight-binding formalism. It is found that in the presence of mirror symmetry, there exists a level crossing at the Fermi level in the energy spectrum of a TCNP, leading to giant orbital paramagnetism (GOP), in spite of the curvatures and hybridizations of the outer toroidal carbon nanotube (TCN). When the mirror symmetry is broken by rotating the inner C(60)s, however, two level crossings appear at the Fermi level, and the GOP changes into a very small diamagnetic response. The results reveal the GOP in a filled TCN, depending on the characteristics of the filling materials and temperature.

Odd-even width effect on persistent current in zigzag hexagonal graphene rings.

The electronic structure and thus the persistent current of zigzag hexagonal graphene rings are investigated within the tight-binding formalism. The flux-dependent energy spectrum is grouped into bands with six levels per band due to inter-valley scattering at the corners of the ring. It is found that the degeneracy at the Fermi level is determined by the even or odd quality of the ring width N. The sample ring becomes metallic at odd N but semiconducting at even N, showing up a strange odd-even width effect. In metallic rings, the persistent current within a flux period is linearly changed with magnetic flux varphi, while it is a sinusoidal periodical function of varphi in semiconducting rings. In addition, with increasing N, the persistent current exponentially decreases (increases) at odd (even) N, but finally falls into the consistence with each other at enough large N, showing that the odd-even effect may be experimentally observable only in narrow rings.

Visible photon-avalanche upconversion in Ho3+ singly doped beta-Na(Y1.5Na0.5)F6 under 980 nm excitation.

Visible IR-to-green photon-avalanche upconversion is reported in an Ho3+ singly doped beta-Na(Y1.5Na0.5)F6 crystal under 980 nm excitation. Upconverted green, red, and IR emissions are observed at 540, 645, and 751 nm, respectively. Temporal evolution and excitation power dependent upconversion intensity are measured, suggesting that a photon-avalanche mechanism is responsible for the upconversion process. It is believed that an efficient cross relaxation (5S2,5I8)-->(5I6,5I6) mainly performs the population of 5I6 excited state, resulting in the intense photon-avalanche upconversion emission in the synthesized samples.

Raman frequency shift in oxygen-functionalized carbon nanotubes.

Based on density functional theory, the geometrical and electronic structures of oxygen-functionalized single-wall carbon nanotubes (O-SWCNs) are obtained, of which the vibrational properties are calculated in terms of lattice dynamics theory. Both bond expansion and contraction are found to coexist in O-SWCNs. A distinct Raman shift is observed in the radial breathing mode (RBM) and the G modes, depending not only on the tube diameter and chirality but also on oxygen coverage and adsorption configurations. With the oxygen coverage increasing, interestingly, a nonmonotonic upshift and downshift is observed in the G modes, which is attributed to the competition between the bond expansion and contraction. In addition, the resonance Raman effect at different oxygen coverage, which may be observable in O-SWCNs, is discussed.

Lattice dynamics of carbon chain inside a carbon nanotube.

Based on the density functional theory, we obtain the optimum geometry of carbon chain inside a carbon nanotube. The phonon spectrum and specific heat of such a chain and nanotube hybrid system are calculated in terms of lattice dynamics theory. Some new phonon branches that have been obtained come from the coupling vibrations of the nanotube and the chain. The bending and stretching modes of the chain appear at about 520 cm(-1)and 1935 cm(-1) at Gamma point, respectively. It is found that the softening of G modes results mainly from the chain induced variations in the bond length on nanotube, independent of van der Waals interaction, while the stiffening of radial breathing mode is developed by the competition between the two factors. In the low-frequency region, the vibrational density of states are very different from that of the bare nanotube. Its specific heat implies the underlying quantized phonon structures and much large thermal conductivity in the hybrid system. In addition, the chain-length dependent vibration modes are calculated, from which it is expected that a finite chain of about 14 carbon atoms in the nanotube may produce the experimental Raman peak at about 1850 cm(-1).

Liver ischemia contributes to early islet failure following intraportal transplantation: benefits of liver ischemic-preconditioning.

Early graft failure following intraportal islet transplantation (IPIT) represents a major obstacle for successful islet transplantation. Here, we examined the role of islet emboli in the induction of early graft failure and utilized a strategy of ischemic-preconditioning (IP) to prevent early islet destruction in a model of syngeneic IPIT in STZ-induced diabetic mice. Numerous focal areas of liver necrosis associated with the islet emboli were observed within 24 h post-IPIT. Pro-inflammatory cytokines, IL-1beta and IL-6, were significantly increased 3 h after IPIT, while TNF-alpha was elevated for up to 5 days post-IPIT. Caspase-3 and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling positive cells were observed in the transplanted islets trapped in areas of necrotic liver at 3 h and 1 day post-IPIT. Hyperglycemia was corrected immediately following IPIT of 200 islets, but recurrence of hyperglycemia was observed within 14 days associated with a poor response to glucose challenge. IP, a procedure of pre-exposure of the liver to transient ischemia and reperfusion, protected the liver from embolism-induced ischemic injury and prevented early islet graft failure. These data suggest that islet embolism in the portal vein is a major cause of functional loss following IPIT that can be prevented by liver IP.

Electronic structure of carbon nanotori: the roles of curvature, hybridization, and disorder.

An efficient and reasonable procedure is proposed for calculating the electronic structure of carbon nanotori in terms of rotational symmetry, within the tight binding formalism. It is shown that the curvature induced σ(*)-π(*) hybridization effects play an important role in determining the electronic structure of this novel nanostructure. The energy gap of the carbon nanotorus exhibits a well defined oscillation feature with increasing size of the torus, converging to that of the corresponding infinite nanotube, while its density of states spectrum evolves from the characteristic of a zero dimensional system to that of a quasi-one dimensional system. Effects of disorder on the electronic properties are also discussed.