Scoparone chemical modification into semi-synthetic analogues featuring 3-substitution for their anti-inflammatory activity.

Natural products (NPs) continue to serve as a structural model for the development of new bioactive molecules and improve the process of identifying novel medicines. The biological effects of coumarins, one of the most researched compounds among NPs, are currently being thoroughly investigated. In the present investigation, we reported the synthesis of nineteen semi-synthetic 3-substituted scoparone analogues, followed by their characterization using analytical methods such as NMR, HPLC, and HRMS. All compounds screened for in vitro and in vivo study for their ability to reduce inflammation. The SAR study worked effectively for this particular scoparone 3-substitution, as compounds 3, 4, 9, 16, 18, and 20 displayed improved in vitro results for TNF-α than the parent molecule. Similarly, compounds 3, and 17 showed a higher percentage of IL-6 inhibition. Compounds 3, 4, and 12 have also been identified by in vivo studies as promising candidates with higher percent inhibition than the parent scoparone molecule. As evident from all in vitro and in vivo studies, compound 3 showed the most potent anti-inflammatory activity among all.

Connect-seq to superimpose molecular on anatomical neural circuit maps.

The mouse brain contains about 75 million neurons interconnected in a vast array of neural circuits. The identities and functions of individual neuronal components of most circuits are undefined. Here we describe a method, termed "Connect-seq," which combines retrograde viral tracing and single-cell transcriptomics to uncover the molecular identities of upstream neurons in a specific circuit and the signaling molecules they use to communicate. Connect-seq can generate a molecular map that can be superimposed on a neuroanatomical map to permit molecular and genetic interrogation of how the neuronal components of a circuit control its function. Application of this method to hypothalamic neurons controlling physiological responses to fear and stress reveals subsets of upstream neurons that express diverse constellations of signaling molecules and can be distinguished by their anatomical locations.

Serum PTH at 4 h after total thyroidectomy as a predictor of hypocalcemia: a prospective time frame analysis in search of evidence.

INTRODUCTION: There has not been a universal agreement about the timings and the threshold level of PTH that can accurately predict the risk of hypocalcemia. Our study aimed to investigate the changes in the serum PTH levels at various time intervals and correlate it with the development of subsequent hypocalcemia. MATERIALS AND METHODS: All patients had a pre-operative serum PTH done and were again assessed intra-operatively, at 4 h, 24 h, 72 h, and 1 month after the thyroid surgery. Absolute serum PTH value at various time points, absolute change in serum PTH values compared to pre-operative level, and relative change (percentage change) in serum PTH values compared with pre-operative levels were used to predict post-operative Hypocalcemia. RESULTS: 49 patients were included in the study. The sensitivity and negative predictive value was 100% for serum PTH at 4 h. There was a statistically significant difference between the groups that required calcium supplementation versus the group that did not require it. The maximum relative reduction in serum PTH value with respect to the pre-operative level occurred at 4 h in the calcium supplement required group which was 82.5%. Use of combination of 4 h serum PTH and relative change at 4 h yielded the best results. CONCLUSION: A combination of absolute serum PTH level at 4 h and the relative decline in serum PTH at 4 h has the highest diagnostic accuracy. The use of this combined parameter helps to reliably predict patients who would require supplementation.

Satellite Epidemic of Covid-19 Associated Mucormycosis in India: A Multi-Site Observational Study.

BACKGROUND: Sudden upsurge in cases of COVID-19 Associated Mucormycosis (CAM) following the second wave of the COVID-19 pandemic was recorded in India. This study describes the clinical characteristics, management and outcomes of CAM cases, and factors associated with mortality. METHODS: Microbiologically confirmed CAM cases were enrolled from April 2021 to September 2021 from ten diverse geographical locations in India. Data were collected using a structured questionnaire and entered into a web portal designed specifically for this investigation. Bivariate analyses and logistic regression were conducted using R version 4.0.2. RESULTS: A total of 336 CAM patients were enrolled; the majority were male (n = 232, 69.1%), literate (n = 261, 77.7%), and employed (n = 224, 66.7%). The commonest presenting symptoms in our cohort of patients were oro-facial and ophthalmological in nature. The median (Interquartile Range; IQR) interval between COVID diagnosis and admission due to mucormycosis was 31 (18, 47) days, whereas the median duration of symptoms of CAM before hospitalization was 10 (5, 20) days. All CAM cases received antifungal treatment, and debridement (either surgical or endoscopic or both) was carried out in the majority of them (326, 97.02%). Twenty-three (6.9%) of the enrolled CAM cases expired. The odds of death in CAM patients increased with an increase in HbA1c level (aOR: 1.34, 95%CI: 1.05, 1.72) following adjustment for age, gender, education and employment status. CONCLUSION: A longer vigil of around 4-6 weeks post-COVID-19 diagnosis is suggested for earlier diagnosis of CAM. Better glycemic control may avert mortality in admitted CAM cases.

Functional Role of YnfA, an Efflux Transporter in Resistance to Antimicrobial Agents in Shigella flexneri.

Shigella flexneri has become a significant public health concern accounting for the majority of shigellosis cases worldwide. Even though a multitude of efforts is being made into the development of a vaccine to prevent infections, the absence of a licensed global vaccine compels us to enormously depend on antibiotics as the major treatment option. The extensive-unregulated use of antibiotics for treatment along with natural selection in bacteria has led to the rising of multidrug-resistance Shigella strains. Out of the various mechanisms employed by bacteria to gain resistance, efflux transporters are considered to be one of the principal contributors to antimicrobial resistance. The small multidrug-resistance family consists of unique small proteins that act as efflux pumps and are involved in extruding various antimicrobial compounds. The present study aims to demonstrate the role of an efflux transporter YnfA belonging to the SMR family and its functional involvement in promoting antimicrobial resistance in S. flexneri. Employing various genetic, computational, and biochemical techniques, we show how disrupting the YnfA transporter, renders the mutant Shigella strain more susceptible to some antimicrobial compounds tested in this study, and significantly affects the overall transport activity of the bacteria against ethidium bromide and acriflavine when compared with the wild-type Shigella strain. We also assessed how mutating some of the conserved amino acid residues of YnfA alters the resistance profile and efflux activity of the mutant YnfA transporter. This study provides a functional understanding of an uncharacterized SMR transporter YnfA of Shigella.

Nutritional co-therapy with 1,3-butanediol and multi-ingredient antioxidants enhances autophagic clearance in Pompe disease.

Alglucosidase alpha is an orphan drug approved for enzyme replacement therapy (ERT) in Pompe disease (PD); however, its efficacy is limited in skeletal muscle because of a partial blockage of autophagic flux that hinders intracellular trafficking and enzyme delivery. Adjunctive therapies that enhance autophagic flux and protect mitochondrial integrity may alleviate autophagic blockage and oxidative stress and thereby improve ERT efficacy in PD. In this study, we compared the benefits of ERT combined with a ketogenic diet (ERT-KETO), daily administration of an oral ketone precursor (1,3-butanediol; ERT-BD), a multi-ingredient antioxidant diet (ERT-MITO; CoQ10, α-lipoic acid, vitamin E, beetroot extract, HMB, creatine, and citrulline), or co-therapy with the ketone precursor and multi-ingredient antioxidants (ERT-BD-MITO) on skeletal muscle pathology in GAA-KO mice. We found that two months of 1,3-BD administration raised circulatory ketone levels to ≥1.2 mM, attenuated autophagic buildup in type 2 muscle fibers, and preserved muscle strength and function in ERT-treated GAA-KO mice. Collectively, ERT-BD was more effective vs. standard ERT and ERT-KETO in terms of autophagic clearance, dampening of oxidative stress, and muscle maintenance. However, the addition of multi-ingredient antioxidants (ERT-BD-MITO) provided the most consistent benefits across all outcome measures and normalized mitochondrial protein expression in GAA-KO mice. We therefore conclude that nutritional co-therapy with 1,3-butanediol and multi-ingredient antioxidants may provide an alternative to ketogenic diets for inducing ketosis and enhancing autophagic flux in PD patients.

Experimental demonstration of single-span 100-km O-band 4×50-Gb/s CWDM direct-detection transmission.

We report on what is to the best of our knowledge the longest 50-Gb/s/λ O-band wavelength-division multiplexed (WDM) transmission. A pair of in-house built bismuth-doped fiber amplifiers (BDFAs) and the use of Kramers-Kronig detection-assisted single-sideband transmission are adopted to overcome the fiber loss and chromatic dispersion, respectively, in a reach-extended O-band coarse WDM (CWDM) system with a channel spacing of ∼10 nm. Through experiments on an amplified 4×50-Gb/s/λ direct-detection system based on booster and pre-amp BDFAs, we show the superior performance of single-sideband transmission in terms of both optical signal-to-noise ratio sensitivity and uniformity in performance amongst CWDM channels relative to double-sideband transmission after both 75-km and 100-km lengths of single-mode fiber. As a result, up to 100-km reach with comparable performance at all 50-Gb/s channels was achieved without the need for in-line optical amplification.

Practice Guidelines for the Diagnosis of COVID-19-Associated Pulmonary Aspergillosis in an Intensive Care Setting.

Coronavirus disease-2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) is a new disease characterized by secondary Aspergillus mold infection in patients with COVID-19. It primarily affects patients with COVID-19 in critical state with acute respiratory distress syndrome, requiring intensive care and mechanical ventilation. CAPA has a higher mortality rate than COVID-19, posing a serious threat to affected individuals. COVID-19 is a potential risk factor for CAPA and has already claimed a massive death toll worldwide since its outbreak in December 2019. Its second wave is currently progressing towards a peak, while the third wave of this devastating pandemic is expected to follow. Therefore, an early and accurate diagnosis of CAPA is of utmost importance for effective clinical management of this highly fatal disease. However, there are no uniform criteria for diagnosing CAPA in an intensive care setting. Therefore, based on a review of existing information and our own experience, we have proposed new criteria in the form of practice guidelines for diagnosing CAPA, focusing on the points relevant for intensivists and pulmonary and critical care physicians. The main highlights of these guidelines include the role of CAPA-appropriate test specimens, clinical risk factors, computed tomography of the thorax, and non-culture-based indirect and direct mycological evidence for diagnosing CAPA in the intensive care unit. These guidelines classify the diagnosis of CAPA into suspected, possible, and probable categories to facilitate clinical decision-making. We hope that these practice guidelines will adequately address the diagnostic challenges of CAPA, providing an easy-to-use and practical algorithm to clinicians for rapid diagnosis and clinical management of the disease.

BRIDGE ARCH-SHAPED SUBRETINAL FLUID IN NEOVASCULAR AGE-RELATED MACULAR DEGENERATION: Evolution and Outcomes.

PURPOSE: To study factors leading to bridge arch-shaped subretinal fluid (SRF) on optical coherence tomography in wet age-related macular degeneration and evaluate its anatomical and functional outcomes. METHODS: In this single-center, retrospective study, patients with bridge arch-shaped SRF and choroidal neovascular membrane (CNVM) were included. RESULTS: Overall, 623 eyes in 431 patients with chronic CNVM were identified, and 24 eyes (4%) in 21 patients showed bridge arch-shaped SRF. Mean age of patients was 69.19 ± 12.0 years. Type-1 CNVM was noted in 79% cases before development of bridge arch-shaped SRF. Mean early treatment diabetic retinopathy letters visual acuity was 53.93 ± 32.19. Time interval to develop bridge arch-shaped SRF was 21.9 ± 30.63 months. Mean number of intravitreal anti-vascular endothelial growth factor injections given before developing bridge arch-shaped SRF was 6.5 ± 7.09. During the development of bridge arch-shaped SRF, visual acuity reduced by -20.57 ± 31.13 letters (P = 0.033) and fibrotic Type-2 CNVM (n = 18, 75%) was noted. Retinal pigment epithelium tear was noted in 8 eyes (33%). At the final visit, further reduction in visual acuity of -7.136 ± 13.73 early treatment diabetic retinopathy letters (P = 0.011) after developing bridge arch-shaped SRF was seen. Mean number of injections given after developing bridge arch-shaped SRF was 4.76 ± 3.76. CONCLUSION: Bridge arch-shaped SRF is an uncommon finding seen in eyes with Type-2 chronic CNVMs. Presence of retinal pigment epithelium breach and tear and nonaggressive treatment regimen with intravitreal anti-vascular endothelial growth factor injections could be responsible for its pathogenesis. It is a marker of fibrotic enlargement, leading to poor visual outcomes despite showing favorable therapeutic response.

Serum iron indices in COVID-19-associated mucormycosis: A case-control study.

BACKGROUND: Whether dysregulated iron metabolism is associated with COVID-19-associated mucormycosis (CAM) remains unknown. Herein, we compare the serum iron indices in COVID-19 subjects with and without mucormycosis. METHODS: We conducted a case-control study enrolling COVID-19 participants with and without mucormycosis. We compared the baseline serum iron indices (iron, ferritin, total iron-binding capacity [TIBC], unsaturated iron-binding capacity and percentage transferrin saturation) between CAM cases and COVID-19 controls. Additionally, we performed a multivariate logistic regression analysis to assess whether any iron indices are associated with CAM. RESULTS: We enrolled 28 CAM cases (mean age 53.6 years old; 78.6% men) and 26 controls (mean age 57.2 years old; 73.1% men). Rhino-orbital (±cerebral) mucormycosis (85.7%) was the most clinical presentation. Diabetes mellitus was more frequent in the cases than controls (75% vs. 42.3%; p = .015). Hypoxaemia during COVID-19 illness was more common in controls than cases. The mean serum iron values (33 vs. 45 µg/dl, p = .03) and TIBC (166.6 vs. 201.6 µg/dl, p = .003) were significantly lower in CAM cases than controls. On multivariate analysis, we found a lower TIBC (odds ratio [OR] 0.97; 95% confidence interval [CI], 0.95-0.99) and diabetes mellitus (OR 5.23; 95% CI, 1.21-22.68) to be independently associated with CAM after adjusting for serum iron, ferritin and glucocorticoid therapy. The case fatality rate of CAM was 73.9%. The iron indices were not significantly different between CAM survivors and non-survivors. CONCLUSIONS: The CAM is associated with lower TIBC levels than COVID-19 subjects without mucormycosis, suggesting dysregulated iron metabolism in its pathogenesis. Further studies are required to confirm our preliminary observations.

Rubus Capped Zinc Oxide Nanoparticles Induce Apoptosis in MCF-7 Breast Cancer Cells.

Rubus fairholmianus (RF) has widely been used to treat various ailments, including pain, diabetes, and cancer. Zinc oxide nanoparticles (ZnO NPs) have drawn attention in modern healthcare applications. Hence, we designed this study to synthesize zinc oxide (ZnO) nanoparticles using R. fairholmianus root extract to investigate its synergistic cytotoxic effect on MCF-7 cells and explore the possible cell death mechanism. ZnO NPs were synthesized via green synthesis using R. fairholmianus root extract, and the effect on MCF-7 cells was determined by looking at cellular morphology, proliferation, cytotoxicity, apoptosis, and reactive oxygen species (ROS). The results showed that cellular proliferation was reduced following treatment with R. fairholmianus capped zinc oxide nanoparticles (RFZnO NPs), while cytotoxicity and ROS were increased. There was also an increase in apoptosis as indicated by the significant increase in cytoplasmic cytochrome c and caspase 3/7 (markers of apoptosis), as well as increased levels of pro-apoptotic proteins (p53, Bax) and decreased levels of anti-apoptotic protein (Bcl-2). In conclusion, these results showed that RFZnO NPs induce apoptosis in breast cancer cells via a mitochondria-mediated caspase-dependent apoptotic pathway and suggest the use of acetone root extract of R. fairholmianus for the treatment of cancer-related ailments.

Gelling properties and microstructure of the silver carp surimi treated with pomegranate (Punica granatum L.) peel extract.

Effects of ethanolic extracts of pomegranate peel (PPE) on the gelling and textural characteristics of silver carp surimi gel was investigated. The peels extracted with 100% ethanol exhibited highest total phenolics, tannin and flavonoid contents. The change of the gelling properties of surimi was explained using infrared spectroscopy, chemical interactions, and scanning electronic microscopy images. Greater number of hydrogen bonds and hydrophobic interactions were found in surimi gel fortified with 0.45% PPE. Amongst all the concentrations of PPE, 0.45% level exhibited the lowest sulfhydryl and primary amino groups and this was concurrent with the highest gel strength. The FT-IR analysis showed a gradual reduction of intensity of the amide I band with the increase of PPE concentration, and also shifting to lower value from control to surimi with PPE 0.90%. Absorption bands like C-N stretching from amide II and N-H deformation from amide III were also detected. The SEM images showed that surimi with 0.45% PPE had most ordered, finest and denser gel network, and was closely integrated with higher breaking force, hardness, and WHC. This study showed the potential of functional components of fruit wastes for improving gelling properties of surimi with additional health benefits for the consumers.

Experimental characterization of an o-band bismuth-doped fiber amplifier.

The recent emergence of bismuth-doped fiber amplifiers (BDFAs) offers the potential to transmit high-speed WDM signals over long distances in the O-band spectral region, thereby greatly enhancing the scope of systems utilizing these wavelengths. In this paper, we present a comprehensive experimental study on several basic characteristics of an O-band BDFA based on a phosphosilicate optical fiber, including the frequency-dependent noise figure, gain tilt (static and dynamic), transient response, and polarization dependent gain. We discuss our findings and their implications on the use of BDFA technology in high bit-rate multichannel systems.

Moderate dose alcohol protects against serum amyloid protein A1-induced endothelial dysfunction via both notch-dependent and notch-independent pathways.

BACKGROUND: Arterial endothelium plays a critical role in maintaining vessel homeostasis and preventing atherosclerotic cardiovascular disease (CVD). Low-to-moderate alcohol (EtOH) consumption is associated with reduced atherosclerosis and stimulates Notch signaling in endothelial cells. The aim of this study was to determine whether EtOH protects the endothelium against serum amyloid A1 (SAA1)-induced activation/injury, and to determine whether this protection is exclusively Notch-dependent. METHODS AND RESULTS: Human coronary artery endothelial cells (HCAEC) were stimulated or not with "pro-atherogenic" SAA1 (1 µM) in the absence or presence of EtOH (25 mM), the Notch ligand DLL4 (3 µg/ml), or the Notch inhibitor DAPT (20 µM). EtOH stimulated Notch signaling in HCAEC, as evidenced by increased expression of the Notch receptor and hrt target genes. Treatment with EtOH alone or stimulation of Notch signaling by DLL4 increased eNOS activity and enhanced HCAEC barrier function as assessed by trans-endothelial electrical resistance. Moreover, EtOH and DLL4 both inhibited SAA1-induced monolayer leakiness, cell adhesion molecule (ICAM, VCAM) expression, and monocyte adhesion. The effects of EtOH were Notch-dependent, as they were blocked with DAPT and by Notch receptor (N1, N4) knockdown. In contrast, EtOH's inhibition of SAA1-induced inflammatory cytokines (IL-6, IFN-γ) and reactive oxygen species (ROS) was Notch-independent, as these effects were unaffected by DAPT or by N1 and/or N4 knockdown. CONCLUSIONS: EtOH at moderate levels protects against SAA1-induced endothelial activation via both Notch-dependent and Notch-independent mechanisms. EtOH's maintenance of endothelium in a nonactivated state would be expected to preserve vessel homeostasis and protect against atherosclerosis development.

Numerical and experimental study on the impact of chromatic dispersion on O-band direct-detection transmission.

The recent emergence of efficient O-band amplification technologies has enabled the consideration of O-band transmission beyond short reach. Despite the O-band being a low chromatic dispersion (CD) window, the impact of CD will become increasingly significant when extending the reach of direct-detection (DD) systems. In this work, we first numerically investigate the 3-dB bandwidth of single-mode fibers (SMF) and the CD-restricted transmission reach in intensity-modulation DD systems, confirming the significant difference between low- and high-dispersion O-band wavelengths. We then carry out experimental transmission studies over SMF for distances of up to 70 km at two different wavelengths, the low-dispersion 1320 nm and the more dispersive 1360 nm, enabled by the use of an O-band bismuth-doped fiber amplifier as a preamplifier at the receiver. We compare three 50-Gb/s optical DD formats, namely, Nyquist on-off keying (OOK), Nyquist 4-ary pulse amplitude modulation (PAM4) and Kramers-Kronig detection-assisted single-sideband quadrature phase shift keying (KK-QPSK) half-cycle subcarrier modulation. Our results show that at both wavelengths, OOK and QPSK exhibit better bit error rate performance than PAM4. When transmitting over 70-km of SMF at the less dispersive wavelength of 1320 nm, 50-Gb/s OOK modulation offers more than 1.5-dB optical power sensitivity improvement at the photodiode (PD) compared to 50-Gb/s QPSK. Conversely, at 1360 nm, the required optical power to the PD can be reduced by more than 3 dB by using QPSK instead of OOK.

Is there an association between zinc and COVID-19-associated mucormycosis? Results of an experimental and clinical study.

BACKGROUND: The enormous increase in COVID-19-associated mucormycosis (CAM) in India lacks an explanation. Zinc supplementation during COVID-19 management is speculated as a contributor to mucormycosis. We conducted an experimental and clinical study to explore the association of zinc and mucormycosis. METHODS: We inoculated pure isolates of Rhizopus arrhizus obtained from subjects with CAM on dichloran rose Bengal chloramphenicol (DRBC) agar enriched with (three different concentrations) and without zinc. At 24 h, we counted the viable colonies and measured the dry weight of colonies at 24, 48 and 72 h. We also compared the clinical features and serum zinc levels in 29 CAM cases and 28 COVID-19 subjects without mucormycosis (controls). RESULTS: We tested eight isolates of R arrhizus and noted a visible increase in growth in zinc-enriched media. A viable count percentage showed a significantly increased growth in four of the eight isolates in zinc-augmented DRBC agar. A time- and concentration-dependent increase in the mean fungal biomass with zinc was observed in all three isolates tested. We enrolled 29 cases of CAM and 28 controls. The mean serum zinc concentration was below the reference range in all the subjects and was not significantly different between the cases and controls. CONCLUSIONS: Half of the R arrhizus isolates grew better with zinc enrichment in vitro. However, our study does not conclusively support the hypothesis that zinc supplementation contributed to the pathogenesis of mucormycosis. More data, both in vitro and in vivo, may resolve the role of zinc in the pathogenesis of CAM.

Transcriptional response of Caenorhabditis elegans when exposed to Shigella flexneri.

In recent years, researchers have begun to use Caenorhabditis elegans as a potential animal model to study Shigella pathogenesis. This study aims to further develop this model using RNA-sequencing to understand which pathways/cellular characteristics are affected and potentially cause death in Shigella-exposed worms. We identified 1631 differentially expressed genes in Shigella-exposed worms (6 h exposure). A number of these genes encode proteins involved in fatty-acid ß-oxidation (FAO), antioxidant defense and autophagy. The down-regulation of acyl-CoA dehydrogenases would impede FAO, reducing the overall energy to combat Shigella in the worm's intestinal tract. This is potentially coupled with the production of reactive oxygen species (ROS) that may not be fully quenched by antioxidant defense proteins, leading to damaged cellular organelles in the worm's intestinal cells. These cells may undergo autophagy to remove the mounting damage, but may eventually undergo cell death.

Intraperitoneal exposure of iron oxide nanoparticles causes dose-dependent toxicity in Wistar rats.

Nanoparticles of iron oxide, with diameters beteween 1 to 100 nm, have notable implications for human health and well being. In the current study, we have investigated the effects of iron oxide nanoparticles (IONP) exposure on general physiology and health of adult Wistar rats. IONP used in the study had spherical shape and average size in the range of 15-20 nm. A total of eight groups of rats were repeatedly injected with 0 (control), 20, 40, and 80 mg IONP per kg body weight intraperitoneally under two different exposure schemes (sub-acute and sub-chronic). IONP exposure caused significant changes in lungs, liver, and kidney indices in both exposure schemes. Sub-acute exposure did not affect body weight gain in treated rats, but longer duration exposure was responsible for significant reduction in body weight. Mesenteries, visceral fatty tissues, and visceral peritoneal membranes demonstrated apparent accumulations of IONP in a dose and time-dependent manner. Hematological analysis showed that total RBC count, hemoglobin content, hematocrit, mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and mean platelet volume (MPV) were not affected by IONP exposure. Total lymphocyte count, however, was elevated in low- and mid-dose treated rats, but not in high-dose group. Serum lactate dehydrogenase (LDH) increased significantly in rats treated with mid and high doses as compared to control. Serum creatinine and blood urea nitrogen levels were also significantly altered in treated rats. Histological study found significant hepatic damage and mild spleen toxicity. Our report suggests that IONP exhibit significant toxicity in rats.

Feasibility of Using Posterior Auricular Artery as Landmark for Identification of Facial Nerve Trunk in Parotid Surgery: A Cadaver Study.

INTRODUCTION: Despite good surgical knowledge of the anatomy of parotid gland and meticulous surgical technique, the incidence of facial palsy in parotid surgeries is up to 26.7% transient and 1.7% complete facial palsy(1). The risk of facial palsy increases further in malignant and revision cases. METHOD: Superficial parotidectomy was done in 14 cadaveric hemi faces in 10 cadavers. Posterior auricular artery and its stylomastoid branch was dissected and facial nerve trunk was identified in all cases. The relationship of posterior auricular artery along with its stylomastoid branch with the facial nerve trunk was studied and recorded. RESULT: Posterior auricular artery was found running inferior to the facial nerve trunk in 12 cadaveric dissection while the posterior auricular artery was found crossing below the main trunk of facial in 2 cadaver dissection. The average distance between PAA and facial nerve trunk was 7 mm (2-14 mm) Stylomastoid artery was found arising from Posterior auricular artery in 12 of 14 and it was found running medial to the facial nerve trunk in all the 8 cadavers. CONCLUSION: Post auricular artery can be used as another landmark for identification of the main trunk of facial nerve in parotid surgeries.

Circularly Polarized Hybrid Dielectric Resonator Antennas: A Brief Review and Perspective Analysis.

Recently, it has been a feasible approach to build an antenna, in view of the potential advantages they offer. One of the recent trends in dielectric resonator antenna research is the use of compound and hybrid structures. Several considerable investigations have been already underway showing quite interesting and significant features in bandwidth, gain, and generation of circular polarization. A critical review on a journey of circularly polarized hybrid dielectric resonator antennas is presented in this article. A general discussion of circular polarization and DR antennas are provided at the forefront. Evolution, significant challenges, and future aspects with new ideas in designing hybrid dielectric resonator antennas are indicated at the end of the review. State-of-the-art advances and associated design challenges of circularly polarized hybrid DR antennas and related empirical formulas used to find resonance frequency of different hybrid modes produced are discussed in this paper.