Metal–insulator–metal (MIM) devices were fabricated with Al/Al
2
TiO
5
stack on Pt/Ti coated SiO
2
/Si substrates and studied the effect of synthesized oxygen flow rate on their composition, ...structural and electrical properties. X-ray photoelectron spectroscopy revealed that the presence of aluminum, titanium and oxygen with the ratio 2:1:5, respectively in the projected mixed insulator Al
2
TiO
5
. XRD spectra showed that the Al
2
TiO
5
high-k films were amorphous in nature. The average grain size observed from atomic force micrograph of the deposited high-k layer could be 25 nm. The capacitance–voltage curves showed reasonably accepted accumulation capacitance values. The films showed the dielectric constant of 19.3 and the leakage current density of 4 × 10
–7
A/cm
2
with good break down behavior. The leakage current in the films can be attributed to the Fowler–Nordheim mechanism due to tunneling of electron at higher electric field and Poole–Frenkel emission in the medium field region since the dielectric films contained the defects and traps.
The wide channels feature combines two adjacent channels to form a new, wider channel to facilitate high-data-rate transmissions in multiple-input-multiple-output (MIMO)-based IEEE 802.11n networks. ...Using a wider channel can exacerbate interference effects. Furthermore, contrary to what has been reported by prior studies, we find that wide channels do not always provide benefits in isolation (i.e., one link without interference) and can even degrade performance. We conduct an in-depth, experimental study to understand the implications of wide channels on throughput performance. Based on our measurements, we design an auto-configuration framework called ACORN for enterprise 802.11n WLANs. ACORN integrates the functions of user association and channel allocation since our study reveals that they are tightly coupled when wide channels are used. We show that the channel allocation problem with the constraints of wide channels is NP-complete. Thus, ACORN uses an algorithm that provides a worst-case approximation ratio of O(1/Δ + 1), with Δ being the maximum node degree in the network. We implement ACORN on our 802.11n testbed. Our evaluations show that ACORN: 1) outperforms previous approaches that are agnostic to wide channels constraints; it provides per-AP throughput gains ranging from 1.5 × 6×; and 2) in practice, its channel allocation module achieves an approximation ratio much better than the theoretically predicted O(1/Δ + 1).
Conversion of carbon dioxide (CO₂) into fuels is an attractive solution to many energy and environmental challenges. However, the chemical inertness of CO₂ renders many electrochemical and ...photochemical conversion processes inefficient. We report a transition metal dichalcogenide nanoarchitecture for catalytic electrochemical CO₂ conversion to carbon monoxide (CO) in an ionic liquid. We found that tungsten diselenide nanoflakes show a current density of 18.95 milliamperes per square centimeter, CO faradaic efficiency of 24%, and CO formation turnover frequency of 0.28 per second at a low overpotential of 54 millivolts. We also applied this catalyst in a light-harvesting artificial leaf platform that concurrently oxidized water in the absence of any external potential.
A Compact Multiple-Input Multiple-Output (MIMO) antenna of size 16 × 26 mm
2
(0.144 λ
0
× 0.234 λ
0
) with improved isolation is presented in this paper. It covers the bandwidth of 2.7–14.9 GHz (FBW ...is 138.2%), which includes the entire UWB, X band, and K
u
band applications. The elements in the structure are placed at a distance of 0.018 λ
0
(2 mm). Optimized values of two parallel strips are placed between the elements for isolation, giving│S
21
│ > 15 dB in most of the band. For further enhancement, four small rectangular strips with different dimensions are protruded to the ground plane, resulting in improved isolation│S
21
│ > 20 dB in most of the band. The radiation efficiency and peak gain values are 86–96% and 0.8–6.6 dBi respectively. Diversity performance is evaluated with the Envelope Correlation Coefficient (ECC < 0.06), Diversity Gain (DG > 9.975 dB) and Total Active Reflection Coefficient (TARC < − 10 dB). The Parametric study has been done for optimization values of the proposed model. The proposed model is simulated & fabricated on the FR4 substrate, tested and verified practically. The measured results almost follow the simulated results.
A very compact and closely spaced circular-shaped UWB – MIMO antenna with slotted T-shaped stubs and protruded strips for high isolation is discussed in the present paper. The fractional bandwidth of ...the proposed model reaches 134.68% from 2.82 GHz to 14.45 GHz with S11 < −10 dB, which covers the unlicensed band 3.1–10.6 GHz approved by FCC in 2002 and X-band applications. The proposed model is fabricated on an FR-4 substrate having dimensions of 0.150 λ0 × 0.244 λ0 (16 × 26 mm2) and tested. The antenna elements in the proposed modal are separated by a small distance of 0.018 λ0 (2 mm). Due to T-shaped stubs and rectangular-shaped protruded strips, the isolation is improved to higher than 22 dB in most of the band. The proposed antenna achieves a maximum peak gain of 6.86 dB at 10.7 GHz. Radiation efficiency is above 91.70% for the entire band. The diversity performance metrics such as Envelope Correlation Coefficient (ECC), Diversity Gain (DG), and Total Active Reflection Coefficient (TARC) are studied and the values are lower than 0.08, greater than 9.984 dB and below −10 dB respectively. The measured and simulated values are found to be in good agreement.
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Diabetic autonomic neuropathy (DAN) is one of the least understood and attended complications which affects the quality of life. Increased oxidative stress, advanced glycation end ...products (AGEs), overactivation of protein kinase C (PKC) and reduced myoinositol content in autonomic nerves are major pathological conditions responsible for DAN. Limited treatment options appeal researchers to search for alternative treatments for DAN. Natural polyphenols are potent antioxidants and have been reported to have beneficial effects in above mentioned pathological conditions.
Diabetes was induced in male Sprague Dawley rats weighing between 190–220 g with streptozotocin (55 mg/kg, i.p.). After 6 weeks of diabetes induction, animals were treated with catechin at dose 25 and 50 mg/kg for the next 28 days. Catechin treatment at dose 25 and 50 mg/kg showed significant improvement in body weight. The treatment with catechin at dose 50 mg/kg; significantly reduced heart hypertrophy (p < 0.001) and plasma glucose levels (p < 0.01). At dose 50 mg/kg catechin significantly improved hemodynamic parameters like heart rate, mean atrial pressure and left ventricular systolic pressure. Catechin also improved oxidative stress parameters in the nerves. Circulatory MMP-9 levels were significantly decreased (p < 0.001) in catechin treated animals at a dose of 50 mg/kg. The histopathology results showed a significant reduction in neuronal damage due to catechin treatment for 28 days.
The results of the study showed that catechin has a beneficial effect in the management of diabetic autonomic neuropathy in rats.
Abietic acid, a constituent of pine resin, is naturally derived from abietadiene a process that requires four enzymes: one (abietadiene synthase) for conversion of the acyclic, achiral ...geranylgeranyl diphosphate to the polycyclic, chiral abietadiene (a complex process involving the copalyl diphosphate intermediate) and then three to oxidize a single methyl group of abietadiene to the corresponding carboxylic acid. In previous work (Nature Chem. 2009, 1, 384), electronic structure calculations on carbocation rearrangements leading to abietadienyl cation revealed an interesting potential energy surface with a bifurcating reaction pathway (two transition-state structures connected directly with no intervening minimum), which links two products one natural and one not yet isolated from Nature. Herein we describe direct dynamics simulations of the key step in the formation of abietadiene (in the gas phase and in the absence of the enzyme). The simulations reveal that abietadiene synthase must intervene in order to produce abietadiene selectively, in essence steering this reaction to avoid the generation of byproducts with different molecular architectures.
Hyperglycemia induced oxidative stress is a prime factor for cardiovascular dysfunction (CVD) in diabetic patients. In this process matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 ...(MMP-9) play important roles. Nobiletin, a polymethoxy citrus flavone, has potent MMP-2 and MMP-9 inhibitory activity in addition to antioxidant activity. We hypothesized that nobiletin due to its MMP-2 & MMP-9 inhibitory and antioxidant effects may ameliorate the cardiovascular dysfunction of diabetes. Diabetes was induced using streptozotocin (50 mg kg(-1) i.p.) in male wistar rats. Four weeks after the induction of diabetes, the rats were treated with nobiletin (10 mg kg(-1), and 25 mg kg(-1)) for a period of the following four weeks. At the end of eight weeks, hemodynamic parameters were recorded, cardiac hypertrophy was measured, and antioxidant assays, and gelatin zymography for MMP-2 & MMP-9 analysis and histopathology were performed. The vascular reactivity of the aorta was measured by recording the contractile response to phenylephrine and relaxation responses to acetylcholine. Treatment with 25 mg kg(-1) nobiletin ameliorated the hemodynamic parameters, oxidative stress, collagen level, MMP-2 and MMP-9 levels, and vascular reactivity significantly compared with vehicle treated diabetic group. Thus, this study suggests that nobiletin ameliorates the CVD of diabetes by inhibiting oxidative stress, MMP-2 & MMP-9 and can be used as a potential therapeutic approach.
Summary
In this communication, a novel compact spanner shaped ultra‐wideband (UWB) antenna is designed for multiple input multiple output (MIMO) system applications. The proposed structure of size 24 ...× 32 mm2 (0.24λ0 × 0.32λ0, λ0 is calculated at lower band frequency) is designed and fabricated on widely available FR4 dielectric material with a dielectric constant of 4.4 and loss tangent of 0.02. The proposed structure comprises two spanner shaped antennas, a defected T‐shaped stub and a pair of small vertical strips. The defected T‐shaped stub and vertical strips are used for getting a complete UWB bandwidth and good isolation between two elements. It is performing from 3.0 to 11.0 GHz with isolation more than 20 dB in most of the operating region. The parametric studies have been done for the required parameters and figured out the surface current distribution at different resonant frequencies within the working region. The MIMO antenna diversity performance is confirmed with low values of envelope correlation coefficient (ECC < 0.005), channel capacity losses (CCL < 0.04 bits/s/Hz), acceptable mean effective gain (MEG ≤ −3 dB, MEG ratio = 0 dB), and total active reflection coefficient (TARC ≤ −10 dB) values. The peak gain values are varying from 1.5 to 6.0 dBi, and the radiation efficiency values are above 83% for the entire operating region. The simulated and measured values are well matched.
In this communication, a novel compact spanner shaped UWB antenna is presented for MIMO system applications. The overall structure size is 24 × 32 mm2 (0.24λ0 × 0.32λ0, λ0 is calculated at lower band frequency). It is operating from 3 to 11 GHz, and isolation is above 20 dB in most of the band. The structure achieves good diversity performance (ECC < 0.005, CCL < 0.04 bits/s/Hz, MEG ≤ −3 dB, and TARC ≤ −10 dB) values.
Neuropathy is a common complication of diabetes affecting a large number of people worldwide. Triphala churna is a formulation mentioned in Ayurveda-a traditional system of medicine. It is a simple ...powder formulation consisting of powders of three fruits,
Emblica officinalis
L.
, Terminalia bellirica
(Gaertn.) Roxb
.
and
Terminalia chebula
Retz. Individual components of Triphala churna have anti-diabetic and antioxidant activities. Hence, this study was designed to evaluate the effect of Triphala churna on diabetic neuropathy. Diabetes was induced with streptozotocin (STZ, 55 mg/kg,
i. p.
) in rats. Animals were grouped and treated orally with Triphala churna at a dose of 250, 500, and 1,000 mg/kg after 6 weeks of diabetes induction for the next 4 weeks. At the end of study, parameters such as body weight, plasma glucose level, motor nerve conduction velocity were determined. The effect of Triphala churna on thermal hyperalgesia, mechanical hyperalgesia, and mechanical allodynia was also determined at the end of study. The plasma cytokine levels like TGF-β1, TNF-α, and IL-1β were determined by ELISA assay. Histopathology study of the sciatic nerve was studied. Western blotting was performed to study the expression of neuronal growth factor.Treatment with Triphala churna showed a significant reduction in plasma glucose and a significant rise in body weight. Triphala treatment significantly increased the motor nerve conduction velocity and decreased the thermal and mechanical hyperalgesia, as well as mechanical allodynia. The treatment significantly inhibited levels of circulatory cytokines like TGF-β1, TNF-α, and IL-1β. Histopathology study confirmed the neuroprotective effect of Triphala churna. The expression of NGF was significantly increased in sciatic nerves after treatment with Triphala churna. From the results, it can be concluded that Triphala churna delays the progression of neuropathy in diabetic rats.
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