Search

This paper analyzes the performance of the Doherty power amplifier (DPA) with the injection of the second harmonic component generated by the carrier power amplifier (PA) into the peaking PA and vice-versa, using a harmonic injection network (HIN). A mathematical analysis is presented to estimate the second harmonic loads seen by the carrier and peaking PAs in the presence of the HIN. Furthermore, a step-by-step design guide to designing a harmonic injection DPA (HI-DPA) is also presented. It is noted that the passive load provided by the output matching network ( $Z'_{c2}$ and $Z'_{p2}$ ), the electrical length of the HIN ( $\theta _{inj}$ ), and the phase difference between the currents of the carrier and peaking PAs ( $\theta _{p}$ ) at the second harmonic are crucial to present an active load to either the carrier or peaking PAs. In the HI-DPA, it is not possible to achieve an active second harmonic load for the carrier and peaking PAs simultaneously. Due to the interaction between the carrier and peaking PAs at the second harmonic, if the carrier PA sees an active load, the peaking PA sees a passive load, and vice-versa. The HI-DPA is designed with the HIN, and its performance is compared with the high-efficiency passive harmonic-tuned DPA. It is demonstrated that both the carrier and peaking PAs cannot see an active impedance at the second harmonic simultaneously. However, it is possible to increase the efficiency in the Doherty load-modulation region with the harmonic injection technique using the HIN. This would be translated into an average efficiency increase when the PA is excited with the modulated signal.

Background: Deep inspiratory breath hold (DIBH) is an established technique to treat left breast cancer with fewer side-effects to the surrounding organs at risk (OARs). However, studies assessing DIBH in resource-poor settings, especially in a government setup, are scarce. Objectives: Our primary objective was to assess and compare the dosimetric changes in the DIBH technique compared to the free breathing technique among patients with left-sided breast cancer undergoing radiation therapy. Materials and Methods: This was a comparative cross-sectional study conducted in the Department of Radiation Oncology, Kidwai Memorial Institute of Oncology (Bengaluru, India), over a period of 24 months. A total of 65 patients were treated with the three-dimensional conformal radiation therapy (3D-CRT) technique either using DIBH or free breathing as per the standard protocol. The dosimetric comparisons for the surrounding OARs, in terms of mean percentage volume receiving 15 Gy (V15Gy) and 20 Gy (V20Gy) in the left lung, V25Gy, V30Gy, V5Gy in the heart the mean dose in Gy received by 25% (V25%) and 40% (V40%) of the heart, V10% and V30% of the left anterior descending artery (LAD) and mean values of Dmean dose (Gy) received by the left lung, heart, and LAD artery were compared between both the techniques. Results: Among 65 patients, 25 (38.4%) were treated by the free breathing technique and 40 (61.6%) by DIBH. Various dosimetric parameters that were significantly lower in the DIBH compared to free breathing techniques included the mean percentage volume of left lung receiving 20 Gy (V20 Gy) (29.5% vs. 23.5%), heart receiving 25 Gy (V25Gy) (6.7% vs. 2.9%) and 30 Gy (12.8% vs. 2.0%), mean values of Dmean received by the heart (7.8 Gy vs. 4.5 Gy) and LAD artery (31.3 Gy vs. 16.9 Gy), mean dose received by 10% volume of LAD (V10%) (36.3 Gy vs. 29.0 Gy) and 30% of LAD artery (V30%) (34.3 Gy vs. 22.2 Gy) (P < 0.001). Conclusion: DIBH significantly decreases the radiation dose delivered to the heart, left lung, and LAD artery. Thus, in patients with left-sided breast cancer, DIBH leads to a lower radiation dose to the OARs, leading to potentially less side-effects.

Purpose: Undetected vision impairment (VI) could negatively affect the overall development in children. School vision screening program is a viable and cost-effective approach for the early identification and management of VI. Aim: This study aims to estimate the prevalence of VI, its risk factors, and ocular morbidity among school children in Telangana, South India. Methods: Children aged 4–15 years attending schools in the study area were screened in this study. The vision screenings were performed in schools by trained community eye health workers using 6/12 tumbling E optotypes. Children who failed the test and/or presented with other eye conditions were referred to vision centers or secondary and tertiary eye care centers. A comprehensive eye examination was conducted in these centers, including cycloplegic refraction and fundus examination. Results: A total of 774,184 children, with a mean age of 9.4 ± 3.27 years, were screened. Overall, 51.49% (N = 398,596) were male. In total, 4.33% [N = 33,528; 95% confidence interval (CI): 4.29–4.38] required referral services, while 1.16% (N = 9,002) had a presenting visual acuity of < 6/12. Multivariate analysis showed a high risk of VI among older children [Adj. odds ratio (OR): 5.75; 95% CI: 5.18–6.38], those with disabilities (Adj. OR: 5.12; 95% CI: 4.14–6.33), female gender (Adj. OR: 1.29; 95% CI: 1.24 - 1.35), and those residing in the urban areas (Adj. OR: 2.87; 95% CI: 2.42–3.39). The main cause of VI was uncorrected refractive errors (74.14%). Conclusion: The prevalence of VI among school children was 1.16% in Telangana, South India, and refractive error was the leading cause of VI among this population. Increasing age, urban location, female gender and other disabilities increase the risk of VI among children.

Collaborative skills have been perceived as the most important skills by learners, instructors, and employers alike in comparison to communication and entrepreneurial skills. Despite its significant role in the workplace, many find that working together with others may complicate tasks due to limited background knowledge and problems with social dynamics. There has not been a single assessment created to assess online collaboration as an integrated performance during group-based tasks. The present study, therefore, attempts to examine learners’ online collaborative performance and the dimensions contributing to effective online collaboration at the tertiary level. A mixed-method research design was adopted using surveys and interviews. A number of 508 undergraduates from local universities were given a questionnaire inquiring about their online collaborative behaviour in group work, while 30 of them were interviewed. The findings indicated that the communication tools and technological facilities category were rated the highest in online collaborative performance, whereas sharing responsibilities was rated the highest in team dynamics. There was also a significant correlation between online collaborative performance and team dynamics. Interview responses showed that learners agreed that good communication, clear goals, and team commitment were important elements for successful online collaboration. Despite the potential to enhance students’ online collaborative performance, collaborative learning is demanding for learners and educators alike.

Background: Laryngoscopy and tracheal intubation are frequently associated with sympathetic stress response. Lignocaine and esmolol are useful to decrease the sympathetic response to laryngoscopy and intubation. Aims and Objectives: The aim of the study was to study the effectiveness of lignocaine and esmolol administered intravenously before laryngoscopy and intubation in attenuating the sympathetic response. Materials and Methods: The prospective, randomized, and controlled study was conducted in Maharajah’s Institute of Medical Sciences Hospital for a period of 18 months from January 2016 to June 2017. A clinical comparative study of attenuation of sympathetic response to laryngoscopy and intubation was done in 90 patients posted for elective surgeries. The sample size estimation is calculated based on findings from the previous study done by Singh et al., (2013).Group I was control group. In this group, no drug was administered. Group II was lignocaine group. Here, patients received 1.5mg/kg lignocaine i.v. bolus. Group III was esmolol group. All patients in this group received 2mg/kg i.v. bolus. Statistical Analysis: Descriptive data presented as Mean±SD and in percentage. Pair-wise comparison between the groups was done by “Z” test. For all tests,“Z” value of >1.96 was considered significant and “P’

Purpose: Addressing childhood vision impairment (VI) is one of the main goals of the World Health Organization's (WHO) combating blindness strategies. The primary aim of this study was to estimate the prevalence of VI, causes, and its risk factors in school children in Krishna district, Andhra Pradesh, India. Methods: Children aged 4–15 years were screened in schools using the 6/12 Snellen optotype by trained community eye health workers, and those who failed the test and those reported or found to have obvious eye conditions were referred to primary (VC), secondary (SC), or tertiary (TC) care centre appropriately, where they underwent a complete eye examination including cycloplegic refraction and fundus examination. Results: A total of 56,988 children were screened, of whom 51.18% were boys. The mean age was 9.69 ± 3.26 years (4–15 years). Overall, 2,802/56,988 (4.92%) children were referred to a VC, of which 632/56,988 (1.11%) required referral to SC/TC. PVA of

Introduction: Brachial plexus are the main nerve supply to the muscles of upper limb and the muscles of the flexor compartment arm are supplied by Musculocutaneous Nerve (McN). Any variations in the nerve innervation of the flexor muscles of arm should be documented as they have clinical implications. Aim: To observe and document the variations in the innervation of muscles of the front of arm and discuss its clinical implications with the help of available literature. Materials and Methods: This cross-sectional descriptive study was done in the Department of Anatomy, Siddhartha Medical College for a period of three years that is from October 2017 to October 2020 on 50 upper limbs, from 25 cadavers. The upper limbs were dissected to observe the innervations of muscles of front of arm. Contents of front of arm were observed. Incidence and percentage of variation in the population was tabulated. Results: Variations in the nerve supply of muscles of front of arm were noticed in 6% of the cases. In two cadavers (4%), all the muscles of right arm except coracobrachialis were innervated by a trifurcated branch from Median Nerve (MN) and the latter was supplied by a separate branch from lateral cord. In another left upper limb two separate branches innervated from lateral cord and supplied all the muscles of arm. In the present study, observed variations were more common on right side than on the left side. Conclusion: Knowledge of such variations are important for the surgeons during surgical exploration of axilla, nerve block in supraclavicular, infraclavicular or axillary region and also during nerve grafting. Also, the study highlights the incidence of variations in a particular region.

Purpose: Screening preschool children for vision-related disorders poses a challenge. This study is designed to determine the agreement and diagnostic accuracy of the spot vision screener (SVS) in screening preschool children compared to screening procedure by vision technicians (VT). Methods: This study was conducted as a part of the ongoing study titled “Initiative for Screening Children for Refractive Errors and other Eye Health Needs (I-SCREEN).” Children from 33 Anganwadis (preschools) in two districts, Adilabad district of Telangana and Krishna district of Andhra Pradesh, in South India, underwent eye health screening by a VT and by a trained community eye health workers (CEHW) using the SVS. Findings were compared for agreement and diagnostic accuracy of assessment. Results: A total of 976 preschool children were screened by the VT and separately by the CEHW using the SVS in Adilabad (15 schools) and Krishna (18 schools) districts. The overall mean age of these children was 2.5 years (SD ± 1.3 years). There were 48 (4.9%) referrals by VT compared to 105 (10.8%) referrals by CEHW using SVS. The overall sensitivity of SVS was 91.7% (95% CI: 80%–97.7%) and the specificity was 93.4% (95% CI: 91.6%–94.9%). Positive predictive value was 41.9% (95% CI: 32.3%–51.9%) and negative predictive value was 99.5% (95% CI: 98.8%–99.9%) with a moderate agreement (0.54; 95% CI 0.49–0.64) between VT screening and screening with SVS. Conclusion: The SVS showed good diagnostic accuracy and agreement in screening for possible vision-related disorders in preschool children.

Purpose: To evaluate the psychological impact of the COVID 19 crisis on ophthalmologists-in-training and practising ophthalmologists during lockdown in India. Methods: An online survey was completed by ophthalmologists and ophthalmology trainees during the lockdown. The information collected included demographics (age, gender), domicile (state, union territory), current professional status (in training or practising), type of practice (solo, group, institutional, governmental, non-governmental), marital status (married, single), impact of COVID-19 on their training or practice, and impact on income and ability to meet living expenses. Psychological distress was assessed using the Patient Health Questionnaire-9 (PHQ-9). Results: In all, 2,355 ophthalmologists responded. Mean age was 42.5 (range, 25-82 years; SD, 12.05) years. Of these, 1,332 (56.7%) were males; 475 (20.2%) were still not in practice; 366 (15.5%) were single; 1,244 (52.8%) felt that COVID-19 would impact on their training or professional work; and 869 (37%) had difficulty in meeting their living expenses. The mean PHQ-9 score was 3.98 (range, 0-27; SD, 4.65). In terms of psychological impact, 768 (32.6%) had some degree of depression; mild in 504 (21.4%), moderate in 163 (6.9%), and severe in 101 (4.3%). Multivariable analysis showed that depression was significantly higher at younger age. The odds of depression decreased by 3% with 1 year increase in age. It was higher in non-practicing ophthalmologists, especially those who were considerably worried about their training or professional growth, and those with difficulty in meeting living expenses. Conclusion: A strikingly high proportion of ophthalmologists are psychologically affected and may require personalized mental health care.

Bacterial biopolymers produced extracellularly due to microbial metabolic activities have gained considerable interest in various engineering applications. The major advantages of bacterial biopolymers is their in-situ production and low water solubility, eliminating the requirement for mixing in granular substrates such as soils. These properties make them highly desirable and preferable to manufactured biopolymers. But for any engineering applications, it is crucial to understand the mechanical properties of these materials, which have been less explored. This investigation is the first attempt to quantify the nano and macro mechanical properties of in-situ bacterial biopolymer dextran produced by bacterial culture Leucononstoc mesenteroids. The fundamental mechanism of bacterial biopolymer-based cementation has been revealed through their morphographic and nanomechanical testing via atomic force microscopy, nanoindentation and scanning electron micrographs. The effect of bacterially produced biopolymers and commercial biopolymers on the macro-mechanical properties of soils was then investigated via needle penetration tests. In-situ biopolymers were found to be highly effective in stabilizing soils with comparable mechanical properties as commercial biopolymers. This study has demonstrated novel methods for testing in situ polymers and opened up the channels for their applications in numerous subsurface as well as surface applications.

Background: Breast cancer is a significant global health concern, affecting millions of women each year. The molecular characterization of breast cancer has become crucial for tailoring personalized treatment strategies and predicting patient outcomes. Among the key biomarkers that guide treatment decisions, the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (Her2/neu) play pivotal roles in determining the disease behavior and response to therapy. Understanding HER-2 expressions and hormone receptors is essential for developing treatment strategies and making decisions regarding breast cancer. Aims and Objectives: The study was conducted to determine the prevalence of different subtypes based on the status of ER, PR, and Her2/neu receptors in this specific patient population and to Analyze the correlation between these molecular subtypes and clinicopathological characteristics, such as age, tumor size, grade, and lymph node status. Materials and Methods: This is a Retrospective observational study conducted on 126 cases of breast carcinoma patients in Government General hospital, Kurnool. Slides were prepared from blocks containing cancer tissue, and immunohistochemical staining was done for ER PR & Her2neu expressions. Interpretation of expressions was done using Allred scoring system for ER, PR and the College of American pathologists guidelines for Her2neu expressions. Statistical analysis was performed to determine the statistical significance by applying chi-square test. Results: The majority of the tumors were HER2/neu negative, positive for ER and PR. When it came to ER and PR positive tumors, most of them were Grade I. The current investigation established a correlation between age, tumor grade and ER and PR, but not with tumor size, lymph node status. There was a correlation between ER and PR expression, but not with HER2/neu. Conclusion: Adjuvant hormonal therapy may result in a favorable outcome for cases that test positive for ER and PR. In order to provide prognostic information and therapeutic benefits, hormone receptor assessment is strongly advised for clinical management of breast cancer patients. [ABSTRACT FROM AUTHOR]

Background: Acute leukemia of ambiguous lineage (ALAL) is infrequent in occurrence with research data available only as small case series, thus leading to a diverse approach in the management. Using "Acute lymphoblastic leukemia (ALL)- type" induction therapy along with a tyrosine kinase inhibitor for t (9,22) has achieved higher remission rates with less toxicity compared with the more intensive AML induction chemotherapy in many case series. The role of immunophenotypic and genetic markers in directing chemotherapy and the utility of targeted therapy is still unknown. In current study, 12 patients who were diagnosed with ALAL have been retrospectively analyzed for patient demographics, hematopathological profile and induction outcomes. Among 12 patients, there were 9 male and 3 female. 25% of the patients showed t (9,22) and 16.6% showed other cytogenetic abnormalities. 5 patients showed remission after induction, 5 failed after induction, 1 expired before induction and 1 deferred chemotherapy. 50% of the patients who were started on ALL- type induction chemotherapy have shown good outcomes. Prospective studies are required to establish the best therapeutic approach in this heterogeneous disease. [ABSTRACT FROM AUTHOR]

Background: Cervical cancer is the second most common cancer in Indian women. In India, cervical cancer contributes to 6-29% of all cancers in women.[1] Late diagnosis results in poor outcomes in the majority of instances of cervical cancer. Cervical carcinoma is the leading cause of mortality (17%) in 30-69 years old women.[1] The aim of this study is to assess the knowledge in Indian women attending oncology Outpatient Department (OPD) at Kurnool medical college and Government General hospital, Kurnool regarding cervical cancer screening and Human Papilloma Virus (HPV) vaccination. The secondary goal of the study was to create awareness among patients attending OPD regarding carcinoma cervix. Materials and Methods: This is a cross sectional study, conducted in 423 women who attended OPD, Department of Oncology, Kurnool Medical college, Kurnool after taking prior permission from hospital ethics committee. After taking informed consent, the questionnaire was provided to the subjects who met inclusion criteria, in the language understandable to them. In case if subject was illiterate, the questionnaire was read aloud by doctor and the responses were recorded. After completion of questionnaire, the doctor shared knowledge regarding etiological factors, screening tests, awareness on vaccination and treatment options available for carcinoma cervix with the patients. Results: Majority of the women have poor knowledge about cervical cancer (75.82% [321/423]) and it's screening (77.7% [329/423]). Conclusion: Many women lacked knowledge regarding cervical cancer and its screening, which is the reason behind late diagnosis and high mortality. It is the high time to create awareness of cancer cervix, its screening and adoption of prevention measures like vaccination to decrease the burden of disease in India. [ABSTRACT FROM AUTHOR]

Background: Coronary artery disease (CAD) is the major disease leading to cause mortality and morbidity. The imbalance between the generation of reactive oxygen species (ROS) and the intrinsic antioxidant defense system leading to the oxidative stress, has been implicated in the pathogenesis of the cardiovascular disease. The formed free radicals and subsequent lipid peroxidation may be responsible for myocardial damage in patients undergoing percutaneous coronary interventions. Therefore, the understanding of the pathophysiological role of ROS generated during or after coronary interventions is essential to improve the success rate of these procedures. Aims and Objective: The aim of this study was to evaluate the time course changes of oxidant and antioxidant status, in patients undergoing percutaneous coronary interventions (PCI). Materials and Methods: The study included 120 consecutive patients (117 males, 3 females; mean age 58.4 years) who underwent elective PCI. Coronary angiography and coronary angioplasty were performed according to the standard protocols. Blood samples were taken just before (0hrs) and at 4 hrs and 24 hrs after coronary interventions to determine the oxidative status i.e. plasma malondialdehyde (MDA) and for antioxidative status, erythrocyte glutathione peroxidase (GPx), erythrocyte glutathione (GSH) and plasma ferric reducing ability of plasma (FRAP). Results: There was significant increase in MDA levels (1.87±0.34, 1.90±0.46, p=0.000), at 4hrs and 24hrs after coronary interventions when compared to baseline levels. After coronary interventions, the GPx activity (12.96±8.37, 12.3±7.76, p=0.000) and FRAP levels (0.73±0.21, 0.70±0.23, p=0.001 respectively) were found to be increased significantly at 4hrs and 24hrs. However, the glutathione levels (2.40±0.57, 2.47±0.53, p=0.040) were decreased at 4hrs and 24hrs after coronary interventions. Conclusion: Our study demonstrates that presence of oxidative stress in coronary interventions. The increase in antioxidants in the present study may be due to paradoxical increase in oxidant levels in patients undergoing coronary interventions.