Comments on the Refractive Index of Tin Sulphide Nano-crystalline Thin Films

The refractive indices of nano-crystalline thin films of Tin (IV) Sulphide (SnS) were investigated here. The experimental data conformed well with the single oscillator model for refractive indices. Based on the this, we explain the increasing trend of refractive index to the improvement in crystal ordering with increasing grain size.Comment: Nine figure

Mercaptophosphonic acids as efficient linkers in quantum dot sensitized solar cells

This work was supported by the Agence Nationale de la Recherche, project QuePhélec (ANR-13-BS10-0011-01). MTS and IDWS are thankful to ERC for financial support for exciton diffusion project, grant number 321305. AKB and IDWS also acknowledge financial support from EPSRC programme grant: structured light, EP/J01771X.Control over the deposition of quantum dots (QDs) on nanostructured semiconductors is very important for the photovoltaic performance of QD sensitized solar cells. The best control is typically achieved using bifunctional molecular linkers, such as mercaptopropionic acid (MPA), to attach the QDs to metal oxides in a specific manner; however some materials, such as ZnO, are not compatible with these molecules due to their pH sensitivity. We have developed new linkers, mercaptophosphonic acids of different length, which allow efficient functionalization of ZnO nanowires and also mesoporous TiO2 without damaging their surface. Detailed XPS and contact angle studies of the mechanism of self-assembly of these acids show that their strong chelation of the oxide surface prevents protonic attack and etching. Using these linkers, we show that colloidal ternary quantum dots, CuInS2, can be conformally and homogeneously deposited on the functionalized metal oxides. Photophysical studies by means of time-resolved photoluminescence spectroscopy confirm efficient electron transfer from the QDs to the metal oxides with the rate and efficiency scaling with respect to the linker length and nature. The efficiency of the QD sensitized solar cells fabricated with such assemblies also strongly depends on the linkers used and follows the trends observed for the charge transfer.PostprintPeer reviewe

Strain Distribution During Growth of Ge/Si(001) and the Effect of Surfactant Layers

Grazing incidence X-ray diffraction has been employed to determine directly the distribution of strain in the plane of the interface during deposition of Ge onto Si(001). The corresponding strain distribution has also been deduced for a relaxed island whose atomic structure has been determined by molecular dynamics. The results illustrate the central role of elastic deformation of islands in the initial stage of strain relief. The results are also compared with those for growth with a Sb surfactant layer which suppresses island formation. An investigation of surfactant-like behaviour is also presented for homoepitaxial growth of Ag on Ag(111), where sub-monolayer coverages of Sb promote a layer-by-layer growth mode over a wide temperature range

Role of sialidase in glycoprotein utilization by Tannerella forsythia

The major bacterial pathogens associated with periodontitis include Tannerella forsythia. We previously discovered that sialic acid stimulates biofilm growth of T. forsythia, and that sialidase activity is key to utilization of sialoconjugate sugars and is involved in host–pathogen interactions in vitro. The aim of this work was to assess the influence of the NanH sialidase on initial biofilm adhesion and growth in experiments where the only source of sialic acid was sialoglycoproteins or human oral secretions. After showing that T. forsythia can utilize sialoglycoproteins for biofilm growth, we showed that growth and initial adhesion with sialylated mucin and fetuin were inhibited two- to threefold by the sialidase inhibitor oseltamivir. A similar reduction (three- to fourfold) was observed with a nanH mutant compared with the wild-type. Importantly, these data were replicated using clinically relevant serum and saliva samples as substrates. In addition, the ability of the nanH mutant to form biofilms on glycoprotein-coated surfaces could be restored by the addition of purified NanH, which we show is able to cleave sialic acid from the model glycoprotein fetuin and, much less efficiently, 9-O-acetylated bovine submaxillary mucin. These data show for the first time that glycoprotein-associated sialic acid is likely to be a key in vivo nutrient source for T. forsythia when growing in a biofilm, and suggest that sialidase inhibitors might be useful adjuncts in periodontal therapy

Formulacija i evaluacija monolitnih matriksnih polimernih filmova za transdermalnu isporuku nitrendipina

The objective of the present work was to develop a suitable transdermal drug delivery system for nitrendipine. Polymeric films of nitrendipine were prepared by the film casting technique (glass ring) on mercury substrate. They were evaluated for physicochemical parameters, in vitro release and ex vivo permeation (heat separated human epidermis). Release of the drug from the films followed anomalous transport (0.5 < n < 1). Polymeric combination containing Eudragit RL 100:PVP K 30 in 4:6 ratio showed the best results. Maximum drug release and skin permeability coefficient in 48 h were 85.8 % and 0.0142 cm h-1, respectively, in formulation C3 (Eudragit RL 100: Plasdone S 630; 4:6) and 88.0 % and 0.0155 cm h-1, respectively, in formulation D3 (Eudragit RL 100: PVP K 30; 4:6). FTIR and TLC studies indicated no drug and polymer interaction.Cilj rada bio je razvoj transdermalnog sustava nitrendipina. Polimerni filmovi nitrendipina pripravljeni su metodom lijevanja (stakleni prsten) na podlozi od žive. Ispitivani su fizičkokemijski parametri, in vitro oslobađanje i ex vivo permeacija (toplinom odvojena humana epiderma). Oslobađanje lijeka iz filmova slijedilo je anomalni transport (0,5 < n < 1). Najbolji rezultati postignuti su kombinacijom polimera Eudragit RL 100 i PVP K 30 u omjeru 4:6. Maksimalno oslobađanje ljekovite tvari i najbolji koeficijent permeacije kroz kožu tijekom 48 h bio je 85,8 %, odnosno 0,0142 cm h1 za formulaciju C3 (Eudragit RL 100 : Plasdone S 630; 4:6) i 88,0 %, odnosno 0,0155 cm h1 za formulaciju D3 (Eudragit RL 100 : PVP K 30; 4:6). FTIR i TLC ukazuju na to da nema interakcije između ljekovite tvari i polimera

Progression of asymptomatic carotid stenosis despite optimal medical therapy

BackgroundDespite level 1 evidence in support of carotid endarterectomy vs medical therapy in selected asymptomatic patients, an alternative posture is that optimal medical therapy (OMT) has not been adequately studied and that such OMT has reduced stroke risk in asymptomatic patients to levels wherein carotid endarterectomy is no longer justified. The goal of this study was to determine the natural history of patients with asymptomatic moderate (50%-69%) carotid artery stenosis (AMCAS) in a contemporary cohort as a function of their associated medical therapy.MethodsPatients with AMCAS determined by duplex ultrasound (DUS) from 2005-2006 were identified in our hospital database. Patients were included in the cohort if they had at least one additional DUS during the 6-year follow-up interval. Patient characteristics including medication history and lipid levels were collected. Patients were considered to have OMT if they were on aspirin and a statin with a low-density lipoprotein level that was always <100 mg/dL. Study end points included progression of carotid disease by DUS to severe stenosis (70%-100%), development of ipsilateral neurologic symptoms (INS) such as stroke or transient ischemic attack, and death.ResultsThere were 900 carotid arteries in 794 patients in the study cohort. The average age was 72.5 years, 77.2% had hypertension, 59.6% had coronary artery disease, and 87.1% were on a statin throughout the study. The low-density lipoprotein cholesterol level was always normal (<100 mg/dL) in 37.8% and accordingly, 241 (30.3%) had OMT as defined above. The 5-year actuarial survival was 81.9% ± 1.3% with no advantage seen with OMT. Multivariate analysis of survival showed statins were protective (hazard ratio [HR], 0.50; confidence interval [CI], 0.34-0.73; P = .0004). The 5-year freedom from plaque progression was 61.2% ± 2.1% with no benefit from OMT vs the control group. Multivariate predictors of plaque progression were chronic kidney disease (HR, 2.1; CI, 1.2-3.7; P = .009), aspirin use (HR, 1.9; CI, 1.2-3.0; P = .01), and the use of calcium channel blockers (HR, 1.4; CI, 1.1-1.8; P = .007). There were 90 (11.3%) patients who developed INS during follow-up (58% of these were strokes), and the 5-year freedom from INS was 88.4% ± 1.5%. Multivariate predictors of INS were diabetes (HR, 2.3; CI, 1.5-3.6; P = .0002) and warfarin use (HR, 1.9; CI, 1.2-2.9; P = .009); while statin use (HR, 0.37; CI, 0.22-0.65; P = .0005) was protective against symptom development.ConclusionsAt the 5-year of follow-up, OMT failed to prevent carotid disease progression or development of ipsilateral symptoms in 45% of patients with AMCAS