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1.
RSC Adv ; 14(4): 2453-2465, 2024 Jan 10.
Article in English | MEDLINE | ID: mdl-38223693

ABSTRACT

Ionic liquids have gained attention as 'designer solvents' since they offer a broad spectrum of properties that can be tuned by altering the constituent ions. In this work, 1-alkyl-2-methyl imidazolium-based ionic liquids with two different alkyl chains (alkyl = hexyl and octyl) have been synthesized and characterized. Since the binary mixture of ionic liquids with molecular solvents can give rise to striking physicochemical properties, the interaction of the synthesized room temperature ionic liquids, 1-hexyl-2-methyl imidazolium bromide [HMIM][Br]/1-octyl-2-methyl imidazolium bromide [OMIM][Br] with DMSO has been examined through density and specific conductance at T = (303.15, 308.15, 313.15 and 318.15) K under atmospheric pressure. The obtained molar volume and excess molar volume are fitted to the Redlich-Kister polynomial equation, and the standard deviation is noted. The positive excess molar volume at elevated temperatures indicates volume expansion due to the mutual loss of dipolar association and differences in the sizes and shapes of the constituent molecules. To have a better understanding of the reactivity and efficacy of 1-hexyl-2-methyl imidazolium bromide and 1-octyl-2-methyl imidazolium bromide with DMSO, the Becke, 3-parameter, Lee-Yang-Parr (B3LYP) correlation function of density functional theory (DFT) has been used. The ORCA Program version 4.0 calculates the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy. The effective reactivities of both the compounds that showed an energy band gap (ΔE), i.e., the difference between ELUMO and EHOMO, are 7.147 and 8.037 kcal mol-1.

2.
Micromachines (Basel) ; 14(12)2023 Nov 29.
Article in English | MEDLINE | ID: mdl-38138341

ABSTRACT

The increasing prevalence of the Internet of Things (IoT) as the primary networking infrastructure in a future society, driven by a strong focus on sustainability and data, is noteworthy. A significant concern associated with the widespread use of Internet of Things (IoT) devices is the insufficient availability of viable strategies for effectively sustaining their power supply and ensuring their uninterrupted functionality. The ability of RF energy-harvesting systems to externally replenish batteries serves as a primary driver for the development of these technologies. To effectively mitigate concerns related to wireless technology, it is imperative to adhere strictly to the mandated limitations on electromagnetic field emissions. A TA broadband polarization-reconfigurable Y-shaped monopole antenna that is improved with a SADEA-tuned smart metasurface is one technique that has been proposed in order to accomplish this goal. A Y-shaped printed monopole antenna is first taken into consideration. To comprehend the process of polarization reconfigurability transitioning from linear to circular polarization (CP), a BAR 50-02 V RF PIN Diode is employed to shorten one of the parasitic conducting strips to the ground plane. A SADEA-driven metasurface, which utilizes the artificial intelligence-driven surrogate model-assisted differential evolution for antenna synthesis, is devised and positioned beneath the radiator to optimize performance trade-offs while increasing the antenna's gain and bandwidth. The ultimate prototype achieves the following: an impedance bandwidth of 2.58 GHz (3.27-5.85 GHz, 48.45%); an axial bandwidth of 1.25 GHz (4.19-5.44 GHz, 25.96%); a peak gain exceeding 8.45 dBic; and when a highly efficient rectifier is integrated, the maximum RF-DC conversion efficiency of 73.82% and DC output of 5.44 V are obtained. Based on the results mentioned earlier, it is considered appropriate to supply power to intelligent sensors and reduce reliance on batteries via RF energy-harvesting mechanisms implemented in hybrid wireless applications.

3.
Sensors (Basel) ; 22(14)2022 Jul 17.
Article in English | MEDLINE | ID: mdl-35891014

ABSTRACT

A miniaturized four-element antenna of 20 mm × 20 mm with edge-to-edge distance of 4.9 mm between the array antennas operating from 4.6−8.6 GHz is investigated in this article. The antenna consists of 4 × integrated dipole driven elements, and complementary split ring resonator (CSRR) metacells are loaded on the both sides of each dipole arms. The loaded meta-couplers magnetically couple to dipole drivers, and the induced resonance effect improves the 10-dB impedance bandwidth (IBW) to 60.6%. To improvise the isolation between antenna elements, metallic vias are implemented that trap electromagnetic (EM)-surface waves to condense into the ground. So, the meta-couplers induce electromagnetic (EM)-propagation as surface wave trapments for radiation and decouple near-field condensed currents, acting as couplers/decouplers. The maximum isolation achieved is >−22.5 dB without any external decoupling network. The diversity parameters indicate good attributes in isotropic, indoor, and outdoor channel environments with an envelope correlation coefficient (ECC) < 0.165 and realized gain of 5.5 dBi with average radiation efficiency of 80−90% in the desired operating bands. An equivalent circuit model using lumped components is designed for the proposed four-element antenna. For validation, a prototype antenna is fabricated and measured to be implemented in 5G applications, which shows good correlation with the full-wave simulated results.

4.
Asian J Neurosurg ; 12(4): 724-726, 2017.
Article in English | MEDLINE | ID: mdl-29114294

ABSTRACT

Even if human beings are the most intelligent among all living beings, they are still not immune to attack from wild animals. Human contact with bears has become more frequent as their habitat is being endangered by frequent deforestation. The sloth bear is one of the few bear species found in India, especially in the hilly areas of Southern Odisha. Bears are highly intelligent and omnivorous animals with long claws coupled with powerful shoulder. Here, we describe the tale of a poor tribal male's encounter with a sloth bear resulting in critical injuries to face, scalp, skull bone, with brain matter fungating-out of the skull. We immediately went for debridement of the, bulged-out contused brain matter and opted for delayed repair of scalp defect with antero-lateral thigh free-flap to save him from fatality along with an acceptable cosmetic repair of the defect.

5.
Asian J Neurosurg ; 12(4): 751-753, 2017.
Article in English | MEDLINE | ID: mdl-29114302

ABSTRACT

Extradural hematoma (EDH) generally occurs in the site of impact, that is, coup injury site. EDH is associated with fracture of skull in many a times due to direct impact. However, EDH in counter coup site is a rare occurrence. Hardly, yet, 12 cases have been reported including this case. Here, we reported a case of a 22-year-old male of contrecoup acute EDH who had sustained head injury due to fall from bike. Physical examination revealed direct impact at the left occipito-parietal region with laceration of scalp and bruise with transient loss of consciousness at the time of injury. There was no evidence of impact on the right side of his head. Computed tomography scan revealed an EDH in the right fronto-temporal region without any bone fracture on bone windows. On intraoperative exploration, it is found that there was coronal suture diastasis with small subgaleal hematoma and right fronto-temporal extradural hematoma. The evacuation of EDH was done. The patient discharged on 3rd postoperative day. It can be concluded that direct impact on head causes exactly opposite hit of brain, and compensatory rebound causes a negative pressure in between the layers causing disruption of vessels and potential accumulation of blood. This mechanism mostly favors for acute subdural hematoma due to compact attachment of dura with cranium. However, in this case, diastasis of coronal suture due to transmitted force is the cause of accumulation of blood extradurally in relatively loosely adhered dura in fronto-temporal region where a potential negative pressure space is created by contrecoup injury.

6.
World Neurosurg ; 98: 876.e9-876.e13, 2017 Feb.
Article in English | MEDLINE | ID: mdl-27894942

ABSTRACT

BACKGROUND: Masson hemangioma is a rare pathologic entity characterized by intravascular papillary endothelial hyperplasia. Although benign, this hemangioma grows to form an expansile compressing mass. This lesion is mostly seen in skin and subcutaneous tissue. Occurrence in the central nervous system is rare. Still rarer is a spinal location with only 5 case reports published to date in the literature. CASE DESCRIPTION: A 32-year-old man presented with paraplegia secondary to extradural compression at the T4-5 level. Histopathologic features were consistent with intravascular papillary endothelial hyperplasia, also known as Masson hemangioma. Differential diagnosis, management, and review of literature are discussed in this report. CONCLUSIONS: This rare pathology should be in the differential diagnosis when spinal cord compressive myelopathy is encountered.


Subject(s)
Hemangioma/complications , Spinal Cord Compression/etiology , Spinal Cord Compression/surgery , Adult , Diagnosis, Differential , Humans , Magnetic Resonance Imaging , Male , Paraplegia/etiology , Spinal Cord Compression/diagnostic imaging
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