Sub-diffraction thin-film sensing with planar terahertz metamaterials

Planar metamaterials consisting of subwavelength resonators have been recently proposed for thin dielectric film sensing in the terahertz frequency range. Although the thickness of the dielectric film can be very small compared with the wavelength, the required area of sensed material is still determined by the diffraction-limited spot size of the terahertz beam excitation. In this article, terahertz near-field sensing is utilized to reduce the spot size. By positioning the metamaterial sensing platform close to the sub-diffraction terahertz source, the number of excited resonators, and hence minimal film area, are significantly reduced. As an additional advantage, a reduction in the number of excited resonators decreases the inter-cell coupling strength, and consequently the resonance Q factor is remarkably increased. The experimental results show that the resonance Q factor is improved by more than a factor of two compared to the far-field measurement. Moreover, for a film with a thickness of λ/375 the minimal area can be as small as 0.2λ × 0.2λ. The success of this work provides a platform for future metamaterial-based sensors for biomolecular detection.

Atomically thin layers of MoS2 via a two step thermal evaporation-exfoliation method

Two dimensional molybdenum disulfide (MoS(2)) has recently become of interest to semiconductor and optic industries. However, the current methods for its synthesis require harsh environments that are not compatible with standard fabrication processes. We report on a facile synthesis method of layered MoS(2) using a thermal evaporation technique, which requires modest conditions. In this process, a mixture of MoS(2) and molybdenum dioxide (MoO(2)) is produced by evaporating sulfur powder and molybdenum trioxide (MoO(3)) nano-particles simultaneously. Further annealing in a sulfur-rich environment transforms majority of the excess MoO(2) into layered MoS(2). The deposited MoS(2) is then mechanically exfoliated into minimum resolvable atomically thin layers, which are characterized using micro-Raman spectroscopy and atomic force microscopy. Furthermore Raman spectroscopy is employed to determine the effect of electrochemical lithium ion exposure on atomically thin layers of MoS(2).

Surface morphology induced localized electric field and piezoresponse enhancement in nanostructured thin films

Nanostructured piezoelectric and ferroelectric thin films are being increasingly used in sensing and actuating microdevices. In this work, we report the experimental discovery of localized electric field enhancement in nanocolumnar piezoelectric thin films and its significant impact on piezoresponse. The magnitude of electric field enhancement is associated with nonflat surface morphologies and is in agreement with theoretical and finite element models. The influence of this surface morphology induced enhancement on piezoresponse is demonstrated using phase field simulations, which also illustrates surface morphology induced strain enhancement. The observed enhancement can be effectively harnessed to improve the sensitivity of related piezoelectric thin film applications.

Heme oxygenase-1 modulates mesangial cell proliferation by p21 Waf1 upregulation

Mesangial cell (MC) proliferation is a hallmark of many progressive renal diseases. Heme oxygenase-1 (HO-1) has been shown to have an anti-proliferative effect on vascular smooth muscle cells. In the present study, we evaluated the role of HO-1 on MC proliferation and the involved molecular mechanism. Both epidermal growth factor (EGF) and hepatocyte growth factor (HGF) not only enhanced mesangial cell HO-1 expression but also stimulated proliferation of MCs. Interestingly, inhibition of HO-1 induction (by zinc protoporphyrin, ZnP) was associated with an accelerated mitogenic response to EGF and HGF in MCs. Induction of HO-1 was associated with enhanced mesangial cell p21 expression. On the other hand, hemoglobin and ZnP inhibited mesangial cell p21 expression. It appears that the effect of HO-1 on MC growth may be mediated through upregulation of p21 expression.

Palpatory method of measuring diastolic blood pressure

BACKGROUND

Most common method for measuring blood pressure is palpatory but only systolic pressure can be measured with this method. In this study we are describing palpatory method of measuring diastolic blood pressure as well. PATIENTS #ENTITYSTARTX00026;

METHODS

We have studied in 200 patients and compared systolic as well as diastolic blood pressures with two methods, auscutatory and palpatory. Systolic and diastolic blood pressure were measured by one of the authors with new palpatory method and noted down. Then an independent observer, who was blinded to the palpatory method's values, measured blood pressure by auscultatory method and noted down. The values were compared in term of range and percentage.

RESULTS

The difference were analysed and found that 102 (51%) patients had systolic and diastolic blood pressure measured by palpatory method, within ± 2 mmHg of auscutatory method, 37 (19%) patients had within ± 4 mmHg, 52 (25%) patients had same readings as with auscutatory method, and in 9 (0.5%) patients it could not be measured.

CONCLUSION

The palpatory method would be very useful where frequent blood pressure measurement are being done manually like in wards, in busy OPD, patient on treadmill and also whenever stethoscope is not available. The blood pressure can be measured in noisy environment too.

Anti-phospholipid syndrome preceding a diagnosis of lepromatous leprosy

A 64-year-old male, with known anti-phospholipid syndrome (APS), which had been diagnosed two years previously, presented to our department with asymptomatic papules over his trunk. Histopathological examination confirmed the diagnosis of lepromatous leprosy. We present this as a case of APS, preceding a diagnosis of lepromatous leprosy.

Microstructural and compositional analysis of strontium-doped lead zirconate titanate thin films on gold-coated silicon substrates

This article discusses the results of transmission electron microscopy (TEM)-based characterization of strontium-doped lead zirconate titanate (PSZT) thin films. The thin films were deposited by radio frequency magnetron sputtering at 300 degrees C on gold-coated silicon substrates, which used a 15 nm titanium adhesion layer between the 150 nm thick gold film and (100) silicon. The TEM analysis was carried out using a combination of high-resolution imaging, energy filtered imaging, energy dispersive X-ray (EDX) analysis, and hollow cone illumination. At the interface between the PSZT films and gold, an amorphous silicon-rich layer (about 4 nm thick) was observed, with the film composition remaining uniform otherwise. The films were found to be polycrystalline with a columnar structure perpendicular to the substrate. Interdiffusion between the bottom metal layers and silicon was observed and was confirmed using secondary ion mass spectrometry. This occurs due to the temperature of deposition (300 degrees C) being close to the eutectic point of gold and silicon (363 degrees C). The diffused regions in silicon were composed primarily of gold (analyzed by EDX) and were bounded by (111) silicon planes, highlighted by the triangular diffused regions observed in the two-dimensional TEM image.

In situ investigation of thermally influenced phase transformations in (Pb 0.92 Sr 0.08)(Zr 0.65 Ti 0.35)O3 thin films using micro-Raman spectroscopy and X-ray diffraction

Thin films of ferroelectric strontium-doped lead zirconate titanate [PSZT, (Pb(0.92)Sr(0.08))(Zr(0.65)Ti(0.35))O(3)] deposited by RF magnetron sputtering have been analyzed by in situ analysis techniques. The in situ techniques employed for this study include micro-Raman spectroscopy and X-ray diffraction (XRD), and variations in thin film structure and orientations for temperatures up to 350 degrees C and 750 degrees C for the respective techniques have been studied. The samples analyzed were PSZT thin films deposited on platinum-coated silicon substrates at either room temperature or at 750 degrees C. In situ measurements using micro-Raman spectroscopy and XRD techniques have been used to identify the Curie point for poly-crystalline PSZT thin films and to determine the temperature-activating significant grain growth for room-temperature-deposited PSZT thin films. To study the presence of hysteresis, analysis was carried out during both temperature ramp-up and ramp-down cycles. Raman measurements showed expected bands (albeit weak), and the in situ measurements have detected variations in the crystal structure of the thin film samples, with negligible variations between the heating and cooling cycles. A combination of the Raman and XRD results has shown that the temperature-activating significant grain growth for the room-temperature-deposited films is about 275 degrees C and the Curie point lies between 325 and 400 degrees C. This relatively high Curie point makes these films suitable for wide temperature range applications.

Nanocolumnar Preferentially Oriented PSZT Thin Films Deposited on Thermally Grown Silicon Dioxide

We report the first instance of deposition of preferentially oriented, nanocrystalline, and nanocolumnar strontium-doped lead zirconate titanate (PSZT) ferroelectric thin films directly on thermal silicon dioxide. No intermediate seed or activation layers were used between PSZT and silicon dioxide. The deposited thin films have been characterised using a combination of diffraction and microscopy techniques.

Microstructural investigation of nickel silicide thin films and the silicide-silicon interface using transmission electron microscopy

This article discusses the results of transmission electron microscopy (TEM)-based investigation of nickel silicide (NiSi) thin films grown on silicon. Nickel silicide is currently used as the CMOS technology standard for local interconnects and in electrical contacts. Films were characterized with a range of TEM-based techniques along with glancing angle X-ray diffraction. The nickel silicide thin films were formed by vacuum annealing thin films of nickel (50 nm) deposited on (100) silicon. The cross-sectional samples indicated a final silicide thickness of about 110 nm. This investigation studied and reports on three aspects of the thermally formed thin films: the uniformity in composition of the film using jump ratio maps; the nature of the interface using high resolution imaging; and the crystalline orientation of the thin films using selected-area electron diffraction (SAED). The analysis highlighted uniform composition in the thin films, which was also substantiated by spectroscopy techniques; an interface exhibiting the desired abrupt transition from silicide to silicon; and desired and preferential crystalline orientation corresponding to stoichiometric NiSi, supported by glancing angle X-ray diffraction results.

Addition of plasmapheresis decreases the incidence of acute antibody-mediated rejection in sensitized patients with strong donor-specific antibodies

BACKGROUND AND OBJECTIVES

The objective of this study was to investigate the effects of desensitization protocols using intravenous Ig with or without plasmapheresis in patients with donor-specific anti-HLA antibodies on prevention of antibody-mediated rejection and downregulation of donor-specific antibodies.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Thirty-five complement-dependent cytotoxicity T cell cross-match-negative but complement-dependent cytotoxicity B cell and/or flow cytometry cross-match-positive kidney transplant recipients were treated with high-dosage intravenous Ig plus Thymoglobulin induction treatment. Donor-specific antibody strength was stratified as strong, medium, or weak by Luminex flow beads. Group 1 patients had weak/moderate and group 2 strong donor-specific antibodies

RESULTS

Whereas no group 1 patients had acute rejection, 66% of group 2 had acute rejection (44% antibody-mediated rejection, 22% cellular rejection). The protocol was then changed to the addition of peritransplantation plasmapheresis to patients with strong donor-specific antibodies (group 3). This change resulted in a dramatic decrease in the acute rejection rate to 7%. During a median 18 mo of follow-up, patient survival was 100, 100, and 93% and graft survival was 100, 78, and 86% in groups 1, 2, and 3, respectively. During follow-up, 17 (52%) patients lost donor-specific antibodies completely, and 10 (30%) lost some of donor-specific antibodies and/or decreased the strength of existing donor-specific antibodies.

CONCLUSIONS

These results indicated that in patients with strong donor-specific antibodies, the addition of plasmapheresis to high-dosage intravenous Ig decreases the incidence of acute rejection. The majority of the patients, whether they received intravenous Ig alone or with plasmapheresis, lost their donor-specific antibodies during follow-up.