Layer-by-layer microcapsules for pH-controlled delivery of small molecules

Praveen Kumar Mandapalli,Venkata Vamsi Krishna Venuganti 한국약제학회 2015 Journal of Pharmaceutical Investigation Vol.45 No.2

The aim of this study is to investigate the influence of pH on the encapsulation and release behavior of charged and neutral small molecules in layer-by-layer microcapsules (LbL-MC). Alternative layers of polystyrene sulfonate and polyallylamine hydrochloride polyelectrolytes were adsorbed onto calcium carbonate sacrificial templates. Six model small molecules including ascorbic acid, indomethacin, imatinib mesylate, rhodamine, 5-fluorouracil and estradiol were studied for their encapsulation in LbL-MC. Encapsulation efficiency was optimized for solute concentration, pH, incubation time and NaCl concentration. In vitro release studies were performed using dialysis membrane method at pH 4, 7.4 and 9. Optical microscopy and zetasizer results showed particles of 3.1 ± 0.2 lm diameter and 1.67 ± 0.87 mV potential. FTIR and differential scanning calorimeter studies confirmed the encapsulation of small molecules in LbL-MC. Encapsulation efficiency (%) of model molecules in LbLMC increased with increase in solute concentration and increase in pH from 2 to 6. Interestingly, encapsulation efficiency was significantly greater for charged small molecules compared to neutral molecules. Extended release of charged molecules was achieved at pH 9. Kinetic modelling of release studies showed Fickian and non-Fickian diffusion of small molecules. In conclusion, LbL-MC can be developed as a potential carrier for small molecules depending on their physical and chemical properties.

상수처리 및 관망/관로 : Hollow fiber MF 막에서의 cake 층 구조가 Backwash에 미치는 영향 연구

김도희,조재원,( Praveen Krishna ),( Colin Hobbs ),( Seung Kwan Hong ) 한국물환경학회 ( 구 한국수질보전학회 ) 2001 공동 추계학술발표회 Vol.2001 No.-

상수처리 및 관망/관로 : Hollow fiber MF 막에서의 cake 층 구조가 Backwash에 미치는 영향 연구

김도희,조재원,( Praveen Krishna ),( Colin Hobbs ),( Seung Kwan Hong ) 대한상하수도학회 2001 공동추계 학술발표회 논문집 Vol.2001 No.-

Direct and Derivative Spectrophotometric Determination of Cobalt (II) in Microgram Quantities with 2-Hydroxy-3-methoxy Benzaldehyde Thiosemicarbazone

Kumar, A.Praveen,Reddy, P.Raveendra,Reddy, V.Krishna Korean Chemical Society 2007 대한화학회지 Vol.51 No.4

분석 시약으로 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC)를 사용하여 코발트 (II) 정량을 위하여 빠르고 간단하고 민감한 분광광도법을 개발하였다. 액상에서 금속이온이 pH 6.0에서 HMBATSC와 갈색의 착물을 형성하였다. 이 착물은 375 nm와 390 nm에서 두 개의 최대 흡수 피크를 보였다. 375 nm에서 많은 흡 수를 보였고, 반면 390 nm에서는 분명한 흡수를 보이지 않았다. Beer's 법칙에서 Co(II)는 0.059-2.357 μg ml-1 범위를 보였다. 이 방법의 몰 흡수와 Sandall's 민감도는 각각 2.74×104 l mol-1 cm-1와 0.0024 μg cm-2 였다. 여러 가지 다른 이온들에 간섭에 대해서도 연구하였다. 화학양론적으로 착체는 1:2 [Co(II)- HMBATSC] 이 였다. 이차 유도 분광광도 법에 의한 Co(II)의 정량방법에 대해서도 제안하였다. 제안된 방법을 alloy steels, 비타민 B12와 생물학 시료에 있는 Co(II)의 정량에 적용하였다. A rapid, simple and sensitive spectrophotometric method was developed for the determination of cobalt(II) using 2-hydroxy-3-methoxy benzaldehyde thiosemicarbazone (HMBATSC) as a analytical reagent. The metal ion in aqueous medium forms a brown coloured complex with HMBATSC at pH 6.0. The complex has two absorption maxima at 375 nm and 390 nm. At 375 nm, the reagent shows considerable absorbance, while at 390 nm the reagent does not shows appreciable absorbance. Hence, analytical studies were carried out at 390 nm. Beer's law is obeyed in the range of 0.059-2.357 μg ml-1 of Co(II). The molar absorptivity and Sandall's sensitivity of the method are 2.74×104 l mol-1 cm-1 and 0.0024 μg cm-2 respectively. The interference of various diverse ions has been studied. The complex has 1:2 [Co(II)- HMBATSC] stoichiometry. A method for the determination of cobalt(II) by second order derivative spectrophotometry has also been proposed. The proposed methods were applied for the determination of cobalt(II) in alloy steels, vitamin B12 and in some biological samples.

Effects of the COVID-19 Pandemic on Cardiac Surgery Practice and Outcomes

Kirun Gopal,Neethu Krishna,Rajesh Jose,Surya Sree Chitra Biju,Jaya Suriya Pichandi,Praveen Kerala Varma 대한흉부외과학회 2022 Journal of Chest Surgery (J Chest Surg) Vol.55 No.1

Background: While the coronavirus disease 2019 (COVID-19) pandemic has affected all aspects of health care, its impact on cardiac surgical practice and outcomes is yet to be determined. We compared the outcomes of our cardiac surgical practice from the past year during the pandemic to those in a similar pre-pandemic period. Methods: Retrospective data were collected from 307 patients who were involved in all adult cardiac surgical procedures performed between March 2020 and February 2021, which was considered the pandemic period, at Amrita Institute of Medical Sciences, India. These were compared with data from the 1-year period between March 2019 and Feb- ruary 2020. During that earlier period, 491 patients underwent surgery, and the surgical outcomes were assessed. Outpatient visit data were also collected to evaluate the effect of COVID-19 on outpatient follow-up visits. Results: A 37% decrease in surgical case volume was observed during the study period. No difference was found in operative mortality between the 2 time periods (3.3% vs. 2.6%, p=0.383). Overall postoperative complications were less frequent during this period, at 23% compared to 38% the previous year (p<0.001). Conclusion: The COVID-19 pandemic caused a dramatic decrease in surgical volume and outpatient medical follow-up. However, the pandemic and its attendant social restric- tions did not yield a significant change in the surgical outcomes of our patients. Hence, it is reasonable to continue cardiac surgical care during global health crises, and this can be done with good results.

A Comprehensive Literature Study on Precision Agriculture: Tools and Techniques

Bh., Prashanthi,A.V. Praveen, Krishna,Ch. Mallikarjuna, Rao International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.12

Due to digitization, data has become a tsunami in almost every data-driven business sector. The information wave has been greatly boosted by man-to-machine (M2M) digital data management. An explosion in the use of ICT for farm management has pushed technical solutions into rural areas and benefited farmers and customers alike. This study discusses the benefits and possible pitfalls of using information and communication technology (ICT) in conventional farming. Information technology (IT), the Internet of Things (IoT), and robotics are discussed, along with the roles of Machine learning (ML), Artificial intelligence (AI), and sensors in farming. Drones are also being studied for crop surveillance and yield optimization management. Global and state-of-the-art Internet of Things (IoT) agricultural platforms are emphasized when relevant. This article analyse the most current publications pertaining to precision agriculture using ML and AI techniques. This study further details about current and future developments in AI and identify existing and prospective research concerns in AI for agriculture based on this thorough extensive literature evaluation.

Clinical presentation of COVID-19 in patients with inflammatory bowel disease: a systematic review and meta-analysis

( Anupam K. Singh ),( Anuraag Jena ),( Praveen Kumar-m ),( Daya Krishna Jha ),( Vishal Sharma ) 대한장연구학회 2022 Intestinal Research Vol.20 No.1

Background/Aims: Coronavirus disease 2019 (COVID-19) is recognized to have variable clinical manifestations. The clinical presentation of patients with inflammatory bowel disease (IBD) having COVID-19 is unclear. Methods: We identified articles reporting about the clinical presentation of COVID-19 in those with underlying IBD from PubMed and Embase. The studies, irrespective of design or language, were included. The overall pooled frequency of various symptoms was estimated. Joanna Briggs Institute Critical appraisal checklist was used to assess the quality of studies. Results: Eleven studies, including 1,325 patients, were included in the pooled analysis. The pooled estimates for clinical presentation were; fever: 67.53% (95% confidence interval [CI], 45.38-83.88), cough: 59.58% (95% CI, 45.01-72.63), diarrhea: 27.26% (95% CI, 19.51-36.69), running nose: 27% (95% CI, 15.26-43.19) and dyspnea: 25.29% (95% CI, 18.52-33.52). The pooled prevalence rates for abdominal pain, nausea and vomiting were 13.08% (95% CI, 9.24-18.19), 10.08% (95% CI, 5.84-16.85) and 8.80% (95% CI, 4.43-16.70) per 100 population, respectively. Conclusions: The clinical presentation of COVID-19 in IBD patients is similar to the general population. (Intest Res 2022;20:134-143)

Predictors of Early Readmissions in Hospitalized Patients With Gastroparesis: A Nationwide Analysis

( Ravi B Pavurala ),( Peter P Stanich ),( Somashekar G Krishna ),( Praveen Guturu ),( Alice Hinton ),( Darwin L Conwell ),( Gokulakrishnan Balasubramanian ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2021 Journal of Neurogastroenterology and Motility (JNM Vol.27 No.3

Background/Aims Gastroparesis is a chronic gastrointestinal disorder that frequently presents with symptoms that are difficult to manage, necessitating frequent hospitalizations. We sought to determine the predictors of early readmission due to gastroparesis based on etiology. Methods We identified all adults discharged with a principal diagnosis of gastroparesis after hospitalization from the 2014 Nationwide Readmission Database. We compared etiology wise (diabetes, post-surgical, and idiopathic) early readmission. Multivariate regression analyses were performed to identify significant predictors of 30-day readmission. Results A total of 12 689 patients were identified, 30.7% diabetic, 2.6% post-surgical, and 66.7% were idiopathic. Patients with diabetic gastroparesis were more likely to be readmitted within 30 days than idiopathic (adjusted odds ratio [aOR], 0.81; 95% confidence interval [CI], 0.69-0.94) and post-surgical gastroparesis (aOR, 0.58; 95% CI, 0.34-0.98). Pyloroplasty was associated with less likelihood of 30-day readmission (aOR, 0.45; 95% CI, 0.20-0.97). In addition, male gender (aOR, 1.18; 95% CI, 1.02-1.37), modified Elixhauser comorbidity score ≥ 3 (aOR, 1.38; 95% CI, 1.18-1.61), chronic pain syndrome (aOR, 1.41; 95% CI, 1.11-1.78), younger (18-64 years) age (aOR, 1.64; 95% CI, 1.34-2.00), need for percutaneous endoscopic gastrostomy/jejunostomy tube (aOR, 2.06; 95% CI, 1.21-3.52), and need for total parenteral nutrition (aOR, 1.70; 95% CI, 1.24-2.35) were associated with increased risk of 30-day readmission. Conclusions One in 5 patients was readmitted with gastroparesis within 30 days. In the diabetic group, diabetes-related complications contributed to readmissions than gastroparesis. Pyloroplasty is associated with reduced early hospital readmission. Prospective studies are needed for validation of these results. (J Neurogastroenterol Motil 2021;27:408-418)

Magneto-transport Properties of La_(0.80)Sr_(0.20)Mn_(1−x)Cu_xO_3 Thin Films Fabricated by Using Spray Pyrolysis

Pawan Kumar,Rakesh Kumar Dwivedi,Pawan Kumar,Ravikant Prasad,Praveen Kumar Siwach,Hari Krishna Singh 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.58 No.1

Thin films of La_(0.80)Sr_(0.20)Mn_(1−x)Cu_xO_3 with x = 0.00, 0.04, 0.08, 0.10, 0.15, and 0.20 were deposited on single-crystal LaAlO_3 (100) (LAO) substrates at 250 ± 10 ℃ by using a nebulized spray pyrolysis technique. Structural, surface, and transport characterizations were done by X-ray diffraction (XRD), atomic force microscopy (AFM) and the standard four probe technique, respectively. XRD patterns revealed the formation of single-phase polycrystalline films with a rhombohedral crystal structure. Cu substitution resulted in a uniform decrease in the metal insulator transition (T_(IM)) temperature up to x = 0.10, followed by a drastic decrease in T_(IM) for x = 0.15. Finally, the metal-insulator transition vanished for higher Cu concentrations (x = 0.20) in the observed temperature range. The variation in T_(IM) with the amount of added Cu is explained on the basis of the double exchange mechanism. Cu substitution has been found to perturb the Mn^(3+)-O-Mn^(4+) network and has a strong influence on T_(IM). The variation in resistivity maxima with temperature for different Cu concentrations showed a systematic trend up to x ∼ 0.10. We also explored the electrical conduction at T > T_(IM) in the framework of small polaron hopping in the adiabatic limit. The activation energy showed a strong dependence on the Cu concentration. The maximum magneto-resistance (MR) up to 10%, was observed for x = 0.15 at low temperatures.