Comprehensive antifungal investigation of green synthesized silver nanoformulation against four agriculturally significant fungi and its cytotoxic applications.

The present study reports the green synthesis of silver nanoparticles (AgNPs) in powder form using the leaf extract of Azadirachta indica. The synthesis of AgNPs was confirmed by UV-vis spectroscopy, FTIR, XRD, FESEM, and EDX. The synthesized AgNPs were in a powdered state and dispersed completely in 5% polyethylene glycol (PEG) and demonstrated prolonged shelf life and enhanced bioavailability over a year without any aggregation. The resulting silver nanoformulation demonstrated complete inhibition against Sclerotinia sclerotiorum and Colletotrichum falcatum and 68% to 80% inhibition against Colletotrichum gloeosporioides and Rhizoctonia solani respectively, at 2000 ppm. The EC50 values determined through a statistical analysis were 66.42, 157.7, 19.06, and 33.30 ppm for S. sclerotiorum, C. falcatum, C. gloeosporioides, and R. solani respectively. The silver nanoformulation also established significant cytotoxicity, with a 74.96% inhibition rate against the human glioblastoma cell line U87MG at 250 ppm. The IC50 value for the cancerous cell lines was determined to be 56.87 ppm through statistical analysis. The proposed silver nanoformulation may be used as a next-generation fungicide in crop improvement and may also find application in anticancer investigations. To the best of our knowledge, this is also the first report of silver nanoformulation demonstrating complete inhibition against the economically significant phytopathogen C. falcatum.

Therapeutic Potential of Capsaicin in various Neurodegenerative Diseases with Special Focus on Nrf2 Signaling.

Neurodegenerative disease is mainly characterized by the accumulation of misfolded proteins, contributing to mitochondrial impairments, increased production of proinflammatory cytokines and reactive oxygen species, and neuroinflammation resulting in synaptic loss and neuronal loss. These pathophysiological factors are a serious concern in the treatment of neurodegenerative diseases. Based on the symptoms of various neurodegenerative diseases, different treatments are available, but they have serious side effects and fail in clinical trials, too. Therefore, treatments for neurodegenerative diseases are still a challenge at present. Thus, it is important to study an alternative option. Capsaicin is a naturally occurring alkaloid found in capsicum. Besides the TRPV1 receptor activator in nociception, capsaicin showed a protective effect in brain-related disorders. Capsaicin also reduces the aggregation of misfolded proteins, improves mitochondrial function, and decreases ROS generation. Its antioxidant role is due to increased expression of an nrf2-mediated signaling pathway. Nrf2 is a nuclear erythroid 2-related factor, a transcription factor, which has a crucial role in maintaining the normal function of mitochondria and the cellular defense system against oxidative stress. Intriguingly, Nrf2 mediated pathway improved the upregulation of antioxidant genes and inhibition of microglial-induced inflammation, improved mitochondrial resilience and functions, leading to decreased ROS in neurodegenerative conditions, suggesting that Nrf2 activation could be a better therapeutic approach to target pathophysiology of neurodegenerative disease. Therefore, the present review has evaluated the potential role of capsaicin as a pharmacological agent for the treatment and management of various neurodegenerative diseases via the Nrf2-mediated signaling pathway.

Molecular dynamics simulations assisted investigation of phytochemicals as potential lead candidates against anti-apoptotic Bcl-B protein.

Due to the multifarious nature of cancer, finding a single definitive cure for this dreadful disease remains an elusive challenge. The dysregulation of the apoptotic pathway or programmed cell death, governed by the Bcl-2 family of proteins plays a crucial role in cancer development and progression. Bcl-B stands out as a unique anti-apoptotic protein from the Bcl-2 family that selectively binds to Bax which inhibits its pro-apoptotic function. Although several inhibitors are reported for Bcl-2 family proteins, no specific inhibitors are available against the anti-apoptotic Bcl-B protein. This study aims to address this research gap by using virtual screening of an in-house library of phytochemicals from seven anti-cancer medicinal plants to identify lead molecules against Bcl-B protein. Through pharmacokinetic analysis and molecular docking studies, we identified three lead candidates (Enterolactone, Piperine, and Protopine) based on appreciable drug-likeliness, ADME properties, and binding affinity values. The identified molecules also exhibited specific interactions with critical amino acid residues of the binding cleft, highlighting their potential as lead candidates. Finally, molecular dynamics simulations and MM/PBSA based binding free energy analysis revealed that Enterolactone (CID_114739) and Piperine (CID_638024) molecules were on par with Obatoclax (CID_11404337), which is a known inhibitor of the Bcl-2 family proteins.Communicated by Ramaswamy H. Sarma.

Chikungunya virus infection in Aedes aegypti is modulated by L-cysteine, taurine, hypotaurine and glutathione metabolism.

BACKGROUND: Blood meal and infections cause redox imbalance and oxidative damage in mosquitoes which triggers the mosquito's system to produce antioxidants in response to increased oxidative stress. Important pathways activated owing to redox imbalance include taurine, hypotaurine and glutathione metabolism. The present study was undertaken to evaluate the role of these pathways during chikungunya virus (CHIKV) infection in Aedes aegypti mosquitoes. METHODOLOGY: Using a dietary L-cysteine supplement system, we upregulated these pathways and evaluated oxidative damage and oxidative stress response upon CHIKV infection using protein carbonylation and GST assays. Further, using a dsRNA based approach, we silenced some of the genes involved in synthesis and transport of taurine and hypotaurine and then evaluated the impact of these genes on CHIKV infection and redox biology in the mosquitoes. CONCLUSIONS: We report that CHIKV infection exerts oxidative stress in the A. aegypti, leading to oxidative damage and as a response, an elevated GST activity was observed. It was also observed that dietary L-cysteine treatment restricted CHIKV infection in A. aegypti mosquitoes. This L-cysteine mediated CHIKV inhibition was coincided by enhanced GST activity that further resulted in reduced oxidative damage during the infection. We also report that silencing of genes involved in synthesis of taurine and hypotaurine modulates CHIKV infection and redox biology of Aedes mosquitoes during the infection.

Formulation and evaluation of SGLT2 inhibitory effect of a polyherbal mixture inspired from Ayurvedic system of medicine.

Background and aim: The ingredients viz., Artemisia roxburghiana, Cissampelos pareira, Stephania glabra, Drimia indica, Roylea cinerea, Tinospora sinensis and Curcuma longa of the present formulation are used to treat diabetes in the Indian traditional medical system. Adopting the concept of multiple herbal mixtures for better therapeutic effects from the ancient Ayurvedic text Sarangdhar Samhita, the present study aimed to develop a polyherbal formulation (PHF) of seven herbs and to evaluate its sodium-glucose cotransporter protein-2 (SGLT2) inhibitory effect on type 2 diabetic rats. Experimental procedure: Streptozotocin (STZ) (60 mg/kg) and nicotinamide (NAM) (120 mg/kg) were intraperitoneally administered to induce type 2 diabetes in Wistar rats. The animals were divided into 5 groups viz. normal control, diabetic control, positive control (dapagliflozin at 0.1 mg/kg) and two test groups (PHF at 250 and 500 mg/kg). Various parameters including blood glucose, serum glutamic pyruvic transaminase (SGPT), serum glutamic-oxaloacetic transaminase (SGOT), bilirubin, triglycerides and creatinine were measured. Results and conclusion: The treatment with PHF (250 and 500 mg/kg) showed a significant (p < 0.05) decrease in blood glucose levels by 56.37% and 58.17%, respectively. The levels of SGOT, SGPT and bilirubin were significantly reduced in PHF-fed diabetic rats. Histopathological examination revealed no major changes in the treated groups as compared to the normal control. The molecular docking study showed strong binding of ß-sitosterol, insulanoline, warifteine, dehydrocorydalmine, taraxerol acetate, lupeol, corydalmine and luteolin to SGLT2 protein. The present study concludes that PHF has promising antidiabetic activity via inhibiting SGLT2 protein without showing any adverse effects.

Essential oil nebulization in mild COVID-19(EONCO): Early phase exploratory clinical trial.

Background: Medications studied for therapeutic benefits in coronavirus disease 2019 (COVID-19) have produced inconclusive efficacy results except for steroids. Objective: A prospective randomized open-label, parallel-arm Phase I/II clinical trial was planned to compare essential oil (EO) blend versus placebo nebulization in mild COVID-19. Methods: A Phase I safety evaluation was carried out in a single ascending and multiple ascending dose study designs. We assessed Phase II therapeutic efficacy on COVID-19 and general respiratory symptoms on days 0, 3, 5, 7, 10, and 14 on the predesigned case record form. Viremia was evaluated on day 0, day 5, and day 10. Results: Dose-limiting toxicities were not reached with the doses, frequencies, and duration studied, thus confirming the formulation's preliminary safety. General respiratory symptoms (p < 0.001), anosmia (p < 0.05), and dysgeusia (p < 0.001) benefited significantly with the use of EO blend nebulization compared to placebo. Symptomatic COVID-19 participants with mild disease did not show treatment benefits in terms of symptomatic relief (p = 1.0) and viremia clearance (p = 0.74) compared to the placebo. EO blend was found to be associated with the reduced evolution of symptoms in previously asymptomatic reverse transcription polymerase chain reaction (RT-PCR)-positive study participants (p = 0.034). Conclusion: EO nebulization appears to be a safer add-on symptomatic relief approach for mild COVID-19. However, the direct antiviral action of the EO blend needs to be assessed with different concentrations of combinations of individual phytochemicals in the EO blend.

Synthesis and catalytic properties of calcium oxide obtained from organic ash over a titanium nanocatalyst for biodiesel production from dairy scum.

The fatty acid methyl ester (FAME) production from dairy effluent scum as a sustainable energy source using CaO obtained from organic ash over titanium dioxide nanoparticles (TNPs) as the transesterification nano-catalyst has been studied. The physical and chemical properties of the synthesized catalysts were characterized, and the effect of different experimental factors on the biodiesel yield was studied. It was revealed that the CaO-TiO2 nano-catalyst displayed bifunctional properties, has both basic and acid phases, and leads to various effects on the catalyst activity in the transesterification process. These bifunctional properties are critical for achieving simultaneous transesterification of dairy scum oil feedstock. According to the reaction results, the catalyst without and with a low ratio of TNPs showed a low catalytic activity. In contrast, the 3Ca-3Ti nano-catalyst had the highest catalytic activity and a strong potential for reusability, producing a maximum biodiesel yield of 97.2% for a 3 wt% catalyst, 1:20 oil to methanol molar ratio for the dairy scum, and a reaction temperature of 70 °C for a period of 120 min under a 300 kPa pressure. The physical properties of the produced biodiesel are within the EN14214 standards.

Antidiabetic effect of aqueous-ethanol extract from the aerial parts of Artemisia roxburghiana.

Artemisia roxburghiana is used for the management of diabetes mellitus in the Indian subcontinent. The present work aimed to validate the traditional claim of the plant in diabetes mellitus. In vitro studies were conducted using α-glucosidase and α-amylase assays whereas streptozotocin-nicotinamide-induced diabetic Wistar rats were used for in vivo study. The aqueous-ethanol extract from the aerial parts was found to exhibit α-glucosidase and α-amylase inhibitory activities with the IC50 values of 31.0 and 17.2 mg/mL, respectively when compared with acarbose (IC50 = 8.6 and 16.25 mg/mL, respectively). The extract showed a significant glucose-lowering effect in diabetic rats at the doses of 200 and 400 mg/kg in a dose-dependent manner, while acarbose (10 mg/kg) was used as a standard. The results revealed that A. roxburghiana aerial parts showed antidiabetic activity via inhibiting α-glucosidase and α-amylase enzymes. The present study also validated the ethnomedicinal claim of the plant in diabetes mellitus.

Self-nanoemulsifying composition containing curcumin, quercetin, Ganoderma lucidum extract powder and probiotics for effective treatment of type 2 diabetes mellitus in streptozotocin induced rats.

Liquid self-nanoemulsifying drug delivery system (L-SNEDDS) of curcumin and quercetin were prepared by dissolving them in isotropic mixture of Labrafil M1944CS®, Capmul MCM®, Tween-80® and Transcutol P®. The prepared L-SNEDDS were solidified using Ganoderma lucidum extract, probiotics and Aerosil-200® using spray drying. These were further converted into pellets using extrusion-spheronization. The mean droplet size and zeta potential of L-SNEDDS were found to be 63.46 ± 2.12 nm and - 14.8 ± 3.11 mV while for solid SNEDDS pellets, these were 72.46 ± 2.16 nm and -38.7 ± 1.34 mV, respectively. The dissolution rate for curcumin and quercetin each was enhanced by 4.5 folds while permeability was enhanced by 5.28 folds (curcumin) and 3.35 folds (quercetin) when loaded into SNEDDS pellets. The Cmax for curcumin and quercetin containing SNEDDS pellets was found 532.34 ± 5.64 ng/mL and 4280 ± 65.67 ng/mL, respectively. This was 17.55 and 3.48 folds higher as compared to their naïve forms. About 50.23- and 5.57-folds increase in bioavailability was observed for curcumin and quercetin respectively, upon loading into SNEDDS pellets. SNEDDS pellets were found stable at accelerated storage conditions. The developed formulation was able to normalize the levels of blood glucose, lipids, antioxidant biomarkers, and tissue architecture of pancreas and liver in streptozotocin induced diabetic rats as compared to their naïve forms.

Rodenticide-induced acute liver failure - Uncommon presentation of commonly available poison.

Rodenticide or 'rat poison' is easily available in a predominantly agrarian economy such as India. Metal phosphides or yellow phosphorous are two common rodenticides. Acute liver failure caused by accidental or suicidal poisoning with rodenticides has been infrequently reported in literature. Liver transplantation offers the best chances of survival in severe intoxication. However, the availability of liver transplantation in resource-limited settings presents a challenge. N-acetyl cysteine has been successfully used in paracetamol poisoning. Its use in rodenticide-induced acute liver failure is not so well known. We report three cases of rodenticide-related acute liver failure, one of them being a pregnant lady. All three patients were given N-acetyl cysteine and two patients improved. It is possible that the administration of N-acetyl cysteine contributed to the improvement in these two.

Protective and therapeutic effects of natural products against diabetes mellitus via regenerating pancreatic ß-cells and restoring their dysfunction.

Diabetes mellitus is a growing public health concern and an increasing interest has been raised to search for new compounds with therapeutic effects on ß-cells. There are chronic insulin resistance and loss of ß-cell mass in the case of type-2 diabetes which covers about 90% of total diabetic patients. This work aims to critically review the protective and regenerative effects of various antidiabetic natural products on pancreatic ß-cells. A thorough literature survey was conducted on the natural molecules and extracts having a protective, regenerative, and repairing effect on ß-cells. The primary source of the literature was online scientific databases such as PubMed, Scopus, and Google Scholar. Besides, selected relevant textbooks were also consulted. Various natural molecules including berberine, curcumin, mangiferin, stevioside and capsaicin, and extracts obtained from the plants like Capsicum annum, Gymnema sylvestre, Stevia rebaudiana and Nymphaea stellate, were found to produce regenerative and anti-apoptosis effects on ß-cells. These natural products were also found to increase insulin secretion by stimulating ß-cells. The present review concluded that a large number of molecules and extracts, abundantly found in nature, possess antidiabetic effect via targeting ß-cells. Further research is warranted to use these agents as a drug against diabetes.

Expanding the Arsenal Against Huntington's Disease-Herbal Drugs and Their Nanoformulations.

Huntington's disease (HD) is an autosomal fatal genetic disease in which degeneration of neuronal cells occurs in the central nervous system (CNS). Commonly used therapeutics are cludemonoamine depletors, antipsychotics, antidepressants, and tranquilizers. However, these drugs cannot prevent the psychotic, cognitive, and behavioral dysfunctions associated with HD. In addition to this, their chronic use is limited by their long-term side effects. Herbal drugs offer a plausible alternative to this and have shown substantial therapeutic effects against HD. Moreover, their safety profile is better in terms of side effects. However, due to limited drug solubility and permeability to reach the target site, herbal drugs have not been able to reach the stage of clinical exploration. In recent years, the paradigm of research has been shifted towards the development of herbal drugs based nanoformulations that can enhance their bioavailability and blood-brain barrier permeability. The present review covers the pathophysiology of HD, available biomarkers, phytomedicines explored against HD, ongoing clinical trials on herbal drugs exclusively for treating HD and their nanocarriers, along with their potential neuroprotective effects.

Evaluation of novobiocin and telmisartan for anti-CHIKV activity.

Chikungunya has re-emerged as an epidemic with global distribution and high morbidity, necessitating the need for effective therapeutics. We utilized already approved drugs with a good safety profile used in other diseases for their new property of anti-chikungunya activity. It provides a base for a fast and efficient approach to bring a novel therapy from bench to bedside by the process of drug-repositioning. We utilized an in-silico drug screening with FDA approved molecule library to identify inhibitors of the chikungunya nsP2 protease, a multifunctional and essential non-structural protein required for virus replication. Telmisartan, an anti-hypertension drug, and the antibiotic novobiocin emerged among top hits on the screen. Further, SPR experiments revealed strong in-vitro binding of telmisartan and novobiocin to nsP2 protein. Additionally, small angle x-ray scattering suggested binding of molecules to nsP2 and post-binding compaction and retention of monomeric state in the protein-inhibitor complex. Protease activity measurement revealed that both compounds inhibited nsP2 protease activity with IC50 values in the low micromolar range. More importantly, plaque formation assays could show the effectiveness of these drugs in suppressing virus propagation in host cells. We propose novobiocin and telmisartan as potential inhibitors of chikungunya replication. Further research is required to establish the molecules as antivirals of clinical relevance against chikungunya.

A Molecular Approach on the Protective Effects of Mangiferin Against Diabetes and Diabetes-related Complications.

BACKGROUND: Diabetes and its related complications are now a global health problem without an effective therapeutic approach. There are many herbal medicines which have attracted much attention as potential therapeutic agents in the prevention and treatment of diabetic complications due to their multiple targets. AIM: The aim of this study is to review available knowledge of mangiferin focusing on its mode of action. METHODS: Mangiferin was extensively reviewed for its antidiabetic activity using online database like Scopus, PubMed, and Google Scholar as well as some offline textbooks. A critical discussion based on the mechanism of action and the future perspectives is also given in the present manuscript. RESULTS: Mangiferin is a natural C-glucoside and mainly obtained from its primary source, the leaves of mango tree (Mangifera indica L.). Therapeutic and preventive properties of mangiferin include antimicrobial, anti-inflammatory, antioxidative, antiallergic, neuroprotective, and cognition-enhancing effects. It dissolves well in water, so it can be easily extracted into infusions and decoctions and hence, a number of researches have been made on the therapeutic effect of this molecule. Recently, mangiferin has been proved to be an effective remedy in diabetes and diabetes-related complications. It is a beneficial natural compound for type 2 diabetes mellitus as it improves insulin sensitivity, modulates lipid profile and reverts adipokine levels to normal. CONCLUSION: This study concludes that mangiferin has the potential to treat diabetes and it can be developed as a therapeutic agent for diabetes and the complications caused by diabetes.

Antiviral activity of ethanolic extract of Nilavembu Kudineer against dengue and chikungunya virus through in vitro evaluation.

BACKGROUND: Currently, no vaccines or modern drugs are available for dengue and chikungunya and only symptomatic relief is provided to the patients. Siddha medicine, a traditional form of indigenous medical system uses specific polyherbal formulations for the treatment of such infections with considerable success. One such polyherbal formulation for the treatment of chikungunya and dengue is Nilavembu kudineer (NVK). The mechanistic details of this drug as an antiviral for chikungunya virus (CHIKV) and dengue virus (DENV) is poorly understood. OBJECTIVES: The current study was undertaken to study the efficacy of NVK as an antiviral formulation against CHIKV and DENV. MATERIALS AND METHODS: Cytotoxicity assays (MTT) were performed to determine the role of NVK as an antiviral during chikungunya and dengue infections in the following conditions-i). post infection, ii). during active infections and iii) protective, not allowing virus infection. RESULTS: It was observed that NVK provides protection against CHIKV and DENV-2 during active infection as well can help to prevent virus infection in the cells and it mainly depends on the cellular availability of drugs for maximum protection against both the infections. CONCLUSION: Our study establishes that extraction protocols are important to ensure maximum efficacy of NVK along with the time of addition of the drug during CHIKV and DENV infections in the cells. This study provides insights to the possible mode of action of NVK in in vitro condition during CHIKV and DENV infection.

Drimia indica: A Plant Used in Traditional Medicine and Its Potential for Clinical Uses.

Drimia indica (Roxb.) Jessop (Asparagaceae) is a reputed Ayurvedic medicine for a number of therapeutic benefits, including for cardiac diseases, indigestion, asthma, dropsy, rheumatism, leprosy, and skin ailments. The present work aimed to critically and extensively review its traditional uses, phytochemistry, pharmacology, toxicology, and taxonomy together with the mechanisms of action of selected extracts of D. indica. A systematic literature survey from scientific databases such as PubMed, Scopus, and Web of Science as well as from some textbooks and classical texts was conducted. The plant, mainly its bulb, contains various bioactive constituents, such as alkylresorcinols, bufadienolides, phytosterols, and flavonoids. Various scientific studies have proven that the plant has anthelmintic, anticancer, antidiabetic, antimicrobial, antioxidant, and wound healing activities. The present work concludes that D. indica has the potential to treat various diseases, mainly microbial infections. This review also suggests that bufadienolides, flavonoids, and steroids might be responsible for its bioactive potential.

Status of Indian medicinal plants in the International Union for Conservation of Nature and the future of Ayurvedic drugs: Shouldn't think about Ayurvedic fundamentals?

The present market for herbal drugs is estimated about ₹40 billion, which is expected to increase by 16% in next 3-4 years. The current production of many Ayurvedic herbs is less than their market demand, which incentivizes adulteration in the Ayurvedic drug supply chain. The present work aims to highlight the most used Ayurvedic plants that have been listed in the International Union for Conservation of Nature's "red list" of endangered or vulnerable plants. The future of Ayurvedic medicines from these listed plants is uncertain, as the collection of herbs from their natural habitat is prohibited and their cultivation does not meet market demands. Many of these plants, such as Taxus baccata and T. wallichiana, are endangered and are only grown in their natural habitats; their cultivation in other areas is impractical. This is the present state, and will worsen as demand continues to grow, with increasing populations and increasing adoption of this system of medicine. It is possible that in coming years most of the Ayurvedic drugs will be adulterated, and will cause only side effects rather than the therapeutic effects. The Ayurvedic fundamentals are under-explored areas where the Ayurvedic practitioners and research scientists can work together. The scientific work on the basic principles will unravel many unknown or little-known facts of this ancient science. Hence, the present review emphasizes the conservation of Ayurvedic herbs, minimization of the use of medicinal plants and the promotion of the research based on Ayurvedic fundamentals.

Ethnomedicinal Investigation of Medicinal Plants of Chakrata Region (Uttarakhand) Used in the Traditional Medicine for Diabetes by Jaunsari Tribe.

The Himalayan region is the treasure house of natural wealth, particularly of medicinal and aromatic plants. These plants are used by the Indian traditional healers for the past many centuries to treat various ailments such as skin disorders, asthma, diabetes, snake bite, fever, pain, eye diseases, diarrhoea, indigestion, jaundice, burn, wound, liver disorder, CNS disorders and urinary tract infection. The indigenous traditional knowledge of medicinal plants and therapies of various local communities has been lost due to changes in traditional culture and the introduction of modern technologies. Therefore, it is essential to explore the traditional knowledge of the indigenous medicinal plants mainly in such areas where there is a severe threat to natural vegetation owing to human inhabitation. The present study aimed to explore the medicinal plants of Chakrata region (Jaunsar-Bawar Hills), Uttarakhand, India used in the folk medicine for the management of diabetes by Jaunsari Tribe. In a comprehensive field survey, the information about the medicinal plants have been mainly collected from the traditional healers and other elderly people belong to the tribal community. All the information about the medicinal plants of the study area was documented in a field book. Various tools have been used to collect the samples for identification purpose and the authentication of the plants was done with the help of taxonomists. The literature on these plants was also searched from online (PubMed and Scopus) as well as from some textbooks and Ayurvedic classical texts. The present survey-based work described a total of 54 plants belonging to 47 genera and 30 families used in the traditional medicine for the management of diabetes in Chakrata region. The information gathered from the local community revealed that the plants are effective in diabetes and one can use most of them without consulting a practitioner or traditional healer. The literature revealed that most of the surveyed plants are already used in the preparation of various antidiabetic formulations such as Chandraprabha vati, Nishamalaki chunra, Amritamehari churna and Nisakathakadi kashayam along with various patent drugs which are frequently prescribed by the Ayurvedic practitioners in India. The present study explored the traditional as well as scientific knowledge on the antidiabetic plants used by the tribal community. The documented information on these plants can be further used by the scientific community to develop new drugs/formulations with the help of modern techniques.