Graphene-Perovskite Fibre Photodetectors.

The integration of optoelectronic devices, such as transistors and photodetectors (PDs), into wearables and textiles is of great interest for applications such as healthcare and physiological monitoring. These require flexible/wearable systems adaptable to body motions, thus materials conformable to non-planar surfaces, and able to maintain performance under mechanical distortions. Here, fibre PDs are prepared by combining rolled graphene layers and photoactive perovskites. Conductive fibres (~500 Ωcm-1) are made by rolling single-layer graphene (SLG) around silica fibres, followed by deposition of a dielectric layer (Al2O3 and parylene C), another rolled SLG as a channel, and perovskite as photoactive component. The resulting gate-tunable PD has a response time~9ms, with an external responsivity~22kAW-1 at 488nm for a 1V bias. The external responsivity is two orders of magnitude higher, and the response time one order of magnitude faster, than state-of-the-art wearable fibre-based PDs. Under bending at 4mm radius, up to~80% photocurrent is maintained. Washability tests show~72% of initial photocurrent after 30 cycles, promising for wearable applications.

High-responsivity graphene photodetectors integrated on silicon microring resonators.

Graphene integrated photonics provides several advantages over conventional Si photonics. Single layer graphene (SLG) enables fast, broadband, and energy-efficient electro-optic modulators, optical switches and photodetectors (GPDs), and is compatible with any optical waveguide. The last major barrier to SLG-based optical receivers lies in the current GPDs' low responsivity when compared to conventional PDs. Here we overcome this by integrating a photo-thermoelectric GPD with a Si microring resonator. Under critical coupling, we achieve >90% light absorption in a ~6 µm SLG channel along a Si waveguide. Cavity-enhanced light-matter interactions cause carriers in SLG to reach ~400 K for an input power ~0.6 mW, resulting in a voltage responsivity ~90 V/W, with a receiver sensitivity enabling our GPDs to operate at a 10-9 bit-error rate, on par with mature semiconductor technology, but with a natural generation of a voltage, rather than a current, thus removing the need for transimpedance amplification, with a reduction of energy-per-bit, cost, and foot-print.

Graphene overcoats for ultra-high storage density magnetic media.

Hard disk drives (HDDs) are used as secondary storage in digital electronic devices owing to low cost and large data storage capacity. Due to the exponentially increasing amount of data, there is a need to increase areal storage densities beyond ~1 Tb/in2. This requires the thickness of carbon overcoats (COCs) to be <2 nm. However, friction, wear, corrosion, and thermal stability are critical concerns below 2 nm, limiting current technology, and restricting COC integration with heat assisted magnetic recording technology (HAMR). Here we show that graphene-based overcoats can overcome all these limitations, and achieve two-fold reduction in friction and provide better corrosion and wear resistance than state-of-the-art COCs, while withstanding HAMR conditions. Thus, we expect that graphene overcoats may enable the development of 4-10 Tb/in2 areal density HDDs when employing suitable recording technologies, such as HAMR and HAMR+bit patterned media.

High pressure torsion induced lowering of Young's modulus in high strength TNZT alloy for bio-implant applications.

An exceptional combination of low Young's modulus (E ~68 GPa) and high flow strength (σf ~1 GPa) was achieved for a consolidated ß-Ti-based metastable Ti-35Nb-7Zr-5Ta (TNZT) alloy subjected to room temperature high-pressure torsion (HPT). The mechanical properties of the alloy were studied by quasistatic nanoindentation tests at different strain rates, where a reduction in Young's modulus E ~73 GPa (NHPT10) and E ~68 GPa (NHPT40) is observed together with an increase in plastic deformability (or HPT rotations). The microstructure evolution with increasing shear strain has been investigated. The stabilized bcc ß-Ti phase with homogeneous nanostructure distribution was observed leading to a low Young's modulus. Severe straining causes a uniform hardness distribution without any noticeable change in the strength of the material. This study may be useful for developing excellent removable implant materials.

Changes in thyroid volume and insulin-like growth factor 1 in pre- and post-pubertal obese children.

BACKGROUND: There is a mutual dynamic interaction between thyroid volume (TV), insulin-like growth factor-1 (IGF-1), and body mass index (BMI). These covariates undergo a change with the transition into puberty. The heterogeneity of the variates and study populations complicate the evaluation of the role of pure pubertal effect. OBJECTIVE: The purpose of this study was to investigate the effect of puberty on IGF-1 and TV in a predetermined homogenous population such as obese children. SUBJECTS AND METHODS: Three hundred and eighty children (202 girls and 178 boys) aged between 6 and 18 were enrolled in this prospective study. The children were assigned to two groups according to their pubertal status, i.e., prepubertal (n = 169) and postpubertal (n = 211). According to age and sex, the obese group (n = 222) was made up of children at and above the 95th percentile, and the control group (n = 158) of children under the 85th percentile. The following parameters were evaluated in all children: BMI, pubertal status, TV, and serum IGF-1, IGFBP-3, and IGF-1:IGFBP-3 molar ratio. RESULTS: In comparison to the prepubertal obese group, the obese group at Tanner stage 2 had a larger mean TV (P = 0.008) and higher IGF-1 level (P = 0.033). There was a positive correlation between IGF-1 and TV both in the prepubertal and pubertal group (r169= 0.369, P = 0.001; r211= 0.316, P = 0.004, respectively), whereas there was no correlation between IGF-1 and BMI (r169= 0.99, P = 0.092; r211= 0.094, P = 0.088, respectively). CONCLUSION: This study showed that the TV and serum IGF-1 levels were increased in obese children in the early stage of puberty and that there was a positive correlation between these two variables in all children, which shows the specific effect of the early stage of puberty on the increase in TV and IGF-1 levels and suggests that increased TV is associated with the increase in IGF-1 levels in a homogenous group such as obese children.

Evaluation of changes in retinal and choroidal thickness using spectral domain optical coherence tomography in unilateral non granulomatous acute anterior uveitis.

PURPOSE: To assess retinal and choroidal thickness changes in eyes with a first episode of unilateral non granulomatous acute anterior uveitis (AU). METHODS: Thirty-one patients with acute unilateral non granulomatous AU who had undergone spectral domain optical coherence tomography (SD-OCT) of both eyes were included in this retrospective study. Retinal thickness (RT) as defined by the Early Treatment Diabetic Retinopathy Study (ETDRS) and subfoveal choroidal thickness (SFCT) obtained by SD-OCT were recorded. Healthy fellow eyes of the patients served as the control. RESULTS: A significant thickening in 1mm of ETDRS subfield and in subfoveal choroid was observed in eyes with acute AU when compared with the unaffected fellow eyes (P=0.005 and P<0.00001, respectively). RT and SFCT of affected eyes did not show a significant difference in terms of HLA-B27 antigen presence or absence (P>0.05, for all). CONCLUSIONS: Significant posterior segment changes were detected in eyes with acute unilateral non granulomatous AU.

Layered material platform for surface plasmon resonance biosensing.

Plasmonic biosensing has emerged as the most sensitive label-free technique to detect various molecular species in solutions and has already proved crucial in drug discovery, food safety and studies of bio-reactions. This technique relies on surface plasmon resonances in ~50 nm metallic films and the possibility to functionalize the surface of the metal in order to achieve selectivity. At the same time, most metals corrode in bio-solutions, which reduces the quality factor and darkness of plasmonic resonances and thus the sensitivity. Furthermore, functionalization itself might have a detrimental effect on the quality of the surface, also reducing sensitivity. Here we demonstrate that the use of graphene and other layered materials for passivation and functionalization broadens the range of metals which can be used for plasmonic biosensing and increases the sensitivity by 3-4 orders of magnitude, as it guarantees stability of a metal in liquid and preserves the plasmonic resonances under biofunctionalization. We use this approach to detect low molecular weight HT-2 toxins (crucial for food safety), achieving phase sensitivity~0.5 fg/mL, three orders of magnitude higher than previously reported. This proves that layered materials provide a new platform for surface plasmon resonance biosensing, paving the way for compact biosensors for point of care testing.

Removal of intra-abdominal mislocated intrauterine devices by laparoscopy.

This retrospective study was carried out on 15 patients who underwent laparoscopy for the removal of a mislocated IUD from 2003 to 2009. The mean duration of usage of an IUD was 16.1 months. The IUD was found in the Pouch of Douglas in six patients; in the posterior wall of the uterus in three patients; in the adnexa in three patients; in the omentum in two patients and it was embedded in the rectal serosa in one patient. The types of the IUDs were TCu-380A (n = 13) and Mirena(®) (n = 2). The mean laparoscopic operation time was 25 min. No major complications occurred. A second ancillary port was required in three patients. All patients were discharged within 24 h. Laparoscopic removal of the intra-abdominal IUD must be the first choice of therapy. If possible, a single ancillary port should be preferred for the removal of mislocated IUDs. We advise that surgical removal and surgical risk should be discussed with the patients, even if asymptomatic.

Transvaginal Burch operation for stress urinary incontinence: 5-year results.

Several techniques have been developed for the management of stress urinary incontinence (SUI). To establish 5-year outcomes for women who underwent our previously described new retropubic suspension operation (transvaginal Burch operation) for SUI at the Meram Medicine Faculty, a prospective study was performed on 231 women who had been operated on for stress incontinence and who had completed 5 years of follow up. We observed complete remission during the follow-up period in 215 women (93%). No major complication related to the procedure was reported, and results were found to be satisfactory and encouraging.

The treatment of 65 women with imperforate hymen by a central incision and application of Foley catheter.

OBJECTIVE: To determine the surgical outcome of 65 women with imperforate hymen treated with a central surgical incision and insertion of a Foley catheter. DESIGN: A prospective study. SETTING: The study was carried out at Department of Obstetrics and Gynecology, Faculty of Meram Medicine, Selcuk University, between 1 January 1996 and 30 June 2006. POPULATION: A total of 65 women diagnosed as imperforate hymen. METHODS: A central oval incision was performed to imperforate hymenal membrane, then 16F Foley catheter was protruded and the balloon was insufflated. Catheter was removed after 2 weeks duration. Estrogen cream was prescribed to all women for application onto hymenal structure for 2 weeks. MAIN OUTCOME MEASURES: Efficacy of procedure in treatment of imperforate hymen, preserving hymenal structural integrity that is accepted as important for virginity in some societies. RESULTS: After the procedure, hymenal orifice created remained open and intact in all women except two women. Closure of artificially created hymenal orifice in these two women was believed to be related to inappropriate administration of estrogen cream. Subsequent treatment with local estrogen treatment results in the hymenal orifice remaining opened in these two women. CONCLUSIONS: We have previously reported the technique in 2002, but now we are able to demonstrate results of our technique in an expanded number of women. This technique is less invasive than other methods and prevents many social problems related to virginity by preventing destruction of the integrity of the hymenal structure and providing an annular-intact hymenal ring.

Contraceptive efficacy and side effects of Implanon.

OBJECTIVE: To determine the efficacy and side effects of Implanon used for long-term contraception. MATERIAL AND METHOD: Prospective study of 80 patients who used Implanon for long-term contraception between January 2004 and January 2006. Side effects, efficacy and removals were recorded. RESULTS: Amenorrhoea, infrequent bleeding and frequent bleeding were reported by 33 (41.25%), 19 (23.75%) and 14 patients (17.5%), respectively. Non-menstrual side effects comprised breast tenderness in 15 patients (18.75%), acne in eight (10%), headache and dizziness in three (3.75%); depressive mood disorders, pelvic pain and loss of libido were mentioned each by two of the women (2.5%). During the study period, Implanon was removed from 20 participants. No problem was encountered during its placement or removal. CONCLUSION: Patients considering use of Implanon must be carefully selected and informed about its expected side effects before placement.