Altering surface fluctuations by blending tethered and untethered chains.

"Partially tethering" a thin film of a polymer melt by covalently attaching to the substrate a fraction of the chains in an unentangled melt dramatically increases the relaxation time of the surface height fluctuations. This phenomenon is observed even when the film thickness, h, is 20 times the unperturbed chain radius, Rg,tethered, of the tethered chains, indicating that partial tethering is more influential than any physical attraction with the substrate. Furthermore, a partially tethered layer of a low average molecular weight of 5k showed much slower surface fluctuations than did a reference layer of pure untethered chains of much greater molecular weight (48k), so the partial tethering effect is stronger than the effects of entanglement and increase in glass transition temperature, Tg, with molecular weight. Partial tethering offers a means of tailoring these fluctuations which influence wetting, adhesion, and tribology of the surface.

Mutation analysis of the NRXN1 gene in autism spectrum disorders.

The aim of this study was to identify the sequence mutations in the Neurexin 1 (NRXN1) gene that has been considered as one of the strong candidate genes. A total of 30 children and adolescents (aged 3-18) with non syndromic autism were enrolled this study. Sequencing of the coding exons and the exon-intron boundaries of the NRXN1 gene was performed. Two known mutations were described in two different cases. Heterozygous S14L was determined in one patient and heterozygous L748I was determined in another patient. The S14L and L748I mutations have been described in the patients with autism before. Both of these mutations were inherited from their father. In this study, two of 30 (6.7%) autism spectrum disorder (ASD) patients carrying NRXN1 gene mutations were detected. It indicates that variants in the NRXN1 gene might confer a risk of developing nonsyndromic ASD. However, due to the reduced penetrance in the gene, the causal role of the NRXN1 gene mutations must be evaluated carefully in all cases.

Correlation of diffusion MRI findings with lesion progression in patients with traumatic intracerebral hemorrhage : diffusion MRI in traumatic intracerebral hemorrhages with progression.

PURPOSE: The aim of this study is to evaluate the association between lesion progression and the ischemic or edematous area that can develop around the hemorrhage in intraparenchymal hemorrhagic lesions originating after head trauma. METHODS: Thirty patients with intracerebral hemorrhage due to head trauma of a mild or intermediate degree were evaluated in this study. Brain diffusion MRI examinations were performed in the first 6 h after trauma in all patients. In addition, a computerized cranial tomography (CCT) was performed upon admission (in the first hour), and at 24 and 48 h after admission. Patients with or without progression of the lesion were compared. RESULTS: The increase in the risk of progression of the lesion in patients with an ischemia/hemorrhage rate > 2 identified in the diffusion MRIs by evaluation of the hemorrhagic and the surrounding ischemic area, obtained in the first 6 h after trauma was found to be statistically significant. The possibility of progression was found to be very low when this rate was less than two. CONCLUSIONS: As a result of the study, the ischemic area was found to be proportionally larger in patients with progression compared to nonprogressing patients with traumatic intracerebral hemorrhage. The ischemia/hemorrhage rate in the diffusion MRI is thought to be an important parameter, beneficial to identify the risk of lesion progression.

Evaluation of potential salivary acetaldehyde production from ethanol in oral cancer patients and healthy subjects.

BACKGROUND: Acetaldehyde has been implicated as a major factor in oral carcinogenesis associated with alcohol consumption. In this study, saliva samples from oral cancer patients and healthy individuals were incubated in vitro with ethanol in order to investigate factors which can influence salivary acetaldehyde production. MATERIALS AND METHODS: A total of 66 individuals (40 males and 26 females, mean age 52 years) participated in the study. Participants were classified into three groups: Group 1 (oral cancer patients [n = 20]); Group 2 (poor dental health status [n = 25]) and Group 3 (good dental health status [n=21]). Every patient chewed a 1g piece of paraffin chewing gum for 1 minute then saliva samples were collected from all individuals. After in vitro incubation of the samples with ethanol, the levels of salivary acetaldehyde production was measured by head space gas chromatography. Kruskal-Wallis and Mann-Whitney tests and Spearman's Correlations analysis were performed for statistical analyses. RESULTS: The salivary acetaldehyde production was significantly higher (p <0.0001) in both group 1 and group 2 when compared to group 3. However, there was no significant difference between group 1 and group 2. Poor dental health status, infrequent oral hygiene habits and dental visits, smoking and presence of a dental prosthesis were significant parameters for increased levels of salivary acetaldehyde production from alcohol. The evaluation of salivary acetaldehyde production after in vitro incubation with ethanol may be useful for early detection of oral cancer. CONCLUSION: According to the results of this study, the significantly higher levels of salivary acetaldehyde production in oral cancer patients and individuals with poor dental health status may suggest a possible link between increased salivary acetaldehyde production and oral cancer. Improved oral hygiene can effectively decrease the level of salivary acetaldehyde production in oral cavity. Hippokratia 2014; 18 (3): 269-274.

Use of antibiotic - impregnated DuraGen® to reduce the risk of infection in dura repair: an in vitro study.

AIM: To investigate the efficacy of antibiotic-impregnated DuraGen® in preventing infection when used for repair of dural defects. MATERIAL AND METHODS: 2 groups of 7 samples were formed. In the first group, normal DuraGen® samples without antibiotic impregnation and in the second group, DuraGen® samples with antibiotic impregnation (30 mg vancomycin) were used. Staphylococcus aureus (ATCC 25923), and Staphylococcus epidermidis (ATCC 12228) were selected for this study. Antimicrobial efficacy was evaluated by counting the number of colonies on and by measuring the diameter of the inhibition zone around the samples. RESULTS: There was no zone diameter around the normal DuraGen® for the 2 types of bacteria. There was significant bacterial growth (10 (5)) according to the colony count. For antibiotic-impregnated DuraGen®, there was a zone with a mean diameter of 32 mm in the agar with S. aureus and a zone with a mean diameter of 35 mm in the agar with S. epidermidis. Antibiotic-impregnated DuraGen® was quite effective against both microorganisms and there was no bacterial growth according to the bacterial colony count. CONCLUSIONS: In our in vitro study, antibiotic-impregnated DuraGen® material significantly inhibited microorganism growth. Our results show that antibiotic-impregnated DuraGen® has the potential to prevent infection.