41 research outputs found
Investigation of heat-acid induced coagulation behaviour of whole milk systems employing front-face fluorescence spectroscopy
The heat-acid-induced coagulation behaviour of whole milk system (buffalo, cow and mixed milk) was studied by steady-state fluorescence spectroscopy exploiting tryptophan as a marker molecule. The varied molecular environment of tryptophan residues in the raw milk systems exerted different fluorescence properties. During the coagulation process, cow milk exhibited significant quenching and bathochromic shift in the emission spectra which was attributed to the low buffering ability and high hydration capacity of cow milk caseins. The results indicated that tryptophan residues of cow milk experienced more dynamic environment throughout the reaction as compared to buffalo milk
ECG Signal Acquisition System for Remote Healthcare Service With Telemetric Capability
Many of the tasks of daily life of human beings became easier with the advent of information communication technology. Complex tasks are becoming simpler with the application of this technology which ensures to meet the challenges with never-ending innovations. However its application in the field of healthcare is still lagging and geared up only in the last decade. In the field of healthcare service information communication technology has tremendous potential in bio-telemetry which is commonly termed as Telehealth or Telemedicine. Telemedicine makes the task easier for remote healthcare service where diagnosis of patients can be performed from remote places. As example, most of the rural areas are lacking of good physicians and healthcare services, and may be monitored by city hospitals through telemedicine. Hence healthcare community requires suitable low cost, low power yet affordable and sustainable gadgets compatible to biomedical signals. In this paper a development effort is presented to acquire ECG signal that is processed and transmitted over communication channel. Keywords: Telehealth, Telemedicine, Information Communication Technology, Remote healthcare, Electrocardiogram, Biopententia
Utjecaj otapala na ekstrakciju fitonutrijenata s potencijalnim antioksidacijskim i antibakterijskim svojstvima iz mekinja sirka
Research background. Sorghum bran, although considered as an agricultural waste, is an abundant source of various bioactive compounds. These bioactive compounds require specific extraction with particular solvents and therefore ionic liquid and three different conventional solvents, viz. anhydrous methanol, acidified methanol and water were used in this work.
Experimental approach. To evaluate the phytochemicals in the different sorghum bran extracts, total phenol content, flavonoids, condensed tannins and anthocyanins were determined as per standard protocols. Liquid chromatography with tandem mass spectrometryanalysis of extracts was also performed for their phenolic profiling. The antioxidant activity of the extracts was estimated via three assays: 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation decolourization assay and Cu2+ reducing antioxidant capacity (CUPRAC) method. The antibacterial activity against two most opportunistic foodborne pathogens: Escherichia coli and Staphylococcus aureus was measured by agar well diffusion assay and minimum inhibitory concentration (MIC) was determined by serial dilution method.
Results and conclusions. Ionic liquid extract of sorghum bran gave the highest yield ((14.9±0.7) %), which indicated that various possible interactions like Van der Waals forces, H-bonding, hydrophobic and cation-π bonding can occur when ionic liquid is used as an extractant compared to other conventional solvents, although total phenol mass fraction expressed as gallic acid equivalents on dry mass basis was only (7.4±0.7) mg/g. The hydrophobicity of the ionic liquid also helped in efficient extraction of condensed tannins ((63.2±2.1) mg/g expressed on dry mass basis), which resulted in significant antioxidant activity of the ionic liquid extract ((85.2±1.2) µmol/g in DPPH assay, (100.8±0.9) µmol/g in ABTS assay and (63.2±1.9) µmol/g in CUPRAC). An interesting revelation reported in this work is the inability of DPPH assay to evaluate the antioxidant activity in acidic environment. The anhydrous methanolic extract of sorghum bran displayed pH sensitivity, making the extract beneficial for certain applications. Qualitative analysis of extracts revealed greater number of phenolic compounds to be present in methanol and distilled water extracts. Moreover, various derivatives of apigenin and luteolin were also observed in all four extracts. In addition, the acidified methanol extract of the sorghum bran exhibited antimicrobial property at a concentration of 12 mg/mL. A larger inhibition zone was observed against Escherichia coli than Staphylococcus aureus, while the MIC against these two bacteria was 2.2 and 1.1 mg/mL, respectively.
Novelty and scientific contribution. This paper presents the first information on the application of ionic liquids as extracting phase for sorghum bran polyphenols and the quantification of such extracts. As evident from the study, each solvent has its own role in the extraction of bioactive compounds. This work also proves that sorghum bran imparts antibacterial activity against foodborne pathogens.Pozadina istraživanja. Iako se mekinje sirka smatraju poljoprivrednim otpadom, bogat su izvor bioaktivnih spojeva. Za esktrakciju tih bioaktivnih spojeva potrebna su specifična otapala, pa je u radu ispitana mogućnost primjene ionske kapljevine i triju konvencionalnih otapala: bezvodnog metanola, zakiseljenog metanola i vode.
Eksperimentalni pristup. Udjeli ukupnih fenola, flavonoida, kondenziranih tanina i antocijana određeni su standardnim postupcima, radi procjene sastava fitonutrijenata u različitim ekstraktima mekinja sirka. Provedena je i analiza profila fenolnih spojeva pomoću spregnutog sustava tekućinske kromatografije i masene spektrometrije. Antioksidacijska aktivnost ektrakata procijenjena je pomoću tri metode: DPPH, ABTS i CUPRAC. Antibakterijska aktivnost protiv dvaju najčešćih oportunističkih patogena u hrani, bakterija Escherichia coli i Staphylococcus aureus, izmjerena je agar difuzijskim testom, a minimalna inhibicijska koncentracija metodom serijskih razrjeđenja.
Rezultati i zaključci. Najveći je prinos ekstrakta mekinja sirka ((14,9±0,7) %) dobiven ekstrakcijom ionskom kapljevinom, što upućuje na zaključak da njezinom uporabom, za razliku od primjene ostalih konvencionalnih otapala, nastaju različite interakcije, kao što su Van der Waalsove sile, vodikove, hidrofobne i π-veze. Usprkos tome, ukupni udjel fenola, izražen u ekvivalentima galne kiseline po masi suhe tvari, iznosio je samo (7,4±0,7) mg/g. Hidrofobnost ionske kapljevine pospješila je i učinkovitost ekstrakcije kondenziranih tanina ((63,2±2,1) mg/g, izraženo u ekvivalentima katehina po masi suhe tvari), a time i povećala antioksidacijsku aktivnost dobivenog ekstrakta ((85,2±1,2) µmol/g s DPPH, (100,8±0,9) µmol/g s ABTS i (63,2±1,9) µmol/g s CUPRAC metodom). Zanimljivo otkriće ovoga rada bilo je da se metodom DPPH nije mogla odrediti antioksidacijska aktivnost ekstrakta u kiseloj sredini. Ekstrakt mekinja sirka u bezvodnom metanolu bio je osjetljiv na promjenu pH-vrijednosti, zbog čega je bio prikladan za neke primjene. Kvalitativnom analizom ektrakata otkriven je veći broj fenolnih spojeva u ektraktima dobivenim pomoću metanola i destilirane vode. Osim toga, u svim su ekstraktima pronađeni različiti derivati apigenina i luteolina. Ekstrakt mekinja sirka dobiven pomoću zakiseljenog metanola imao je antibakterijska svojstva pri koncentraciji od 12 mg/mL. Opažene su veće zone inhibicije rasta bakterije Escherichia coli nego Staphylococcus aureus, dok su minimalne inhibicijske koncentracije iznosile 2,2 odnosno 1,1 mg/mL.
Novina i znanstveni doprinos. U ovom je radu po prvi put opisana mogućnost primjene ionske kapljevine za ekstrakciju polifenola iz mekinja sirka, te je opisan sastav tako dobivenog ekstrakta. Zaključeno je da svako otapalo ima različitu ulogu u ekstrakciji bioaktivnih spojeva. Također je dokazano da mekinje sirka imaju antibakterijski učinak na patogene mikroorganizme iz hrane
Method development and validation for acrylamide in potato cutlet by UHPLC-MS/MS
Surge in consumption of healthy and safe foods has challenged researchers to develop sensitive, precise, robust
detection and quantification of food contaminants like acrylamide even if they are present in trace. Keeping this
in view, a robust and sensitive analytical method was developed and validated for acrylamide quantification in a
potato-based food product (potato cutlet), using LC-MSMS with positive electrospray ionization (+ESI). The
method consists of adding acrylamide-d3 (deuterium labelled acrylamide) as an internal standard, extraction by
modified QuEChERS method with d-SPE clean-up. Extracts were run on a reverse phase C-18 column for analysis
by liquid chromatography. The limit of detection (LOD) and limit of quantification (LOQ) were determined as 0.7
and 2.0 μg kg− 1
, respectively, demonstrating the sensitivity of the method for trace detection. The developed
method showed excellent results in terms of recoveries (91.0–109.16%), repeatability (RSD 1.8–10.60%),
reproducibility (RSD 2.3–11.24%) and robustness (RSD 1.74–4.54%). The repeatability, reproducibility and
robustness respectively, show the consistency, accuracy and stability of the developed method. The deviations in
ion ratio and retention time were 17.25% and − 0.01 min, respectively. Compared to previous findings, the
current study has achieved lower LOD and LOQ levels that reveals the higher sensitivity of this method for
acrylamide quantification in potato cutletMinistry of Food Processing Industries, Government of India | Ref. Q-29/11/2018-R&DUniversidade de Vigo/CISU
Optical/IR counterpart to the resolved X-ray jet source CXO J172337.5-373442 and its distance
We present results of observations in the optical to mid-infrared wavelengths
of the X-ray source CXO J172337.5-373442, which was serendipitously discovered
in the Chandra images and was found to have a fully resolved X-ray jet. The
observations include a combination of photometry and spectroscopy in the
optical using ground-based telescopes and mid-infrared photometry using
Spitzer. We detect the optical/IR counterpart of CXO J172337.5-373442 and
identify it to be a G9-V star located at a distance of 334+-60~pc. Comparable
values of the hydrogen column densities determined independently from the
optical/IR observations and X-ray observations indicate that the optical source
is associated with the X-ray source. Since the X-ray luminosity can not be
explained in terms of emission from a single G9-V star, it is likely that CXO
J172337.5-373442 is an accreting compact object in a binary system. Thus, CXO
J172337.5-373442 is the nearest known resolved X-ray jet from a binary system,
which is not a symbiotic star. Based on the existing X-ray data, the nature of
the compact object can not be confirmed. However the low luminosity of the
X-ray point source, 7.1x10^{30} Lsun combined with estimates of the age of the
jet and a lack of detection of bright outburst, suggests that the X-ray jet was
launched during extreme quiescence of the object. The measured low X-ray
luminosity of the jet suggests the likelihood of such jets being more
ubiquitous than our current understanding.Comment: Accepted for publication in MNRA
Diagnostic accuracy of commercially available immunochromatographic rapid tests for diagnosis of dengue in India.
BACKGROUND & OBJECTIVES: There is limited evidence regarding the accuracy of dengue rapid diagnostic kits despite their extensive use in India. We evaluated the performance of four immunochromatographic Rapid Diagnostic Test (RDTs) kits: Multisure dengue Ab/Ag rapid test (MP biomedicals; MP), Dengucheck combo (Zephyr Biomedicals; ZB), SD bioline dengue duo (Alere; SD) and Dengue day 1 test (J Mitra; JM). METHODS: This is a laboratory-based diagnostic evaluation study. Rapid tests results were compared to reference non-structural (NS1) antigen or immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) results of 241 dengue-positive samples and 247 dengue-negative samples. Sensitivity and specificity of NS1 and IgM components of each RDT were calculated separately and in combination (either NS1 or IgM positive) against reference standard ELISA. RESULTS: A total of 238, 226, 208, and 146 reference NS1 ELISA samples were tested with MP, ZB, SD, and JM tests, respectively. In comparison to the NS1 ELISA reference tests, the NS1 component of MP, ZB, SD, and JM RDTs demonstrated a sensitivity of 71.8%, 85.1%, 77.2% and 80.9% respectively and specificity of 90.1%, 92.8%, 96.1 %, and 93.6%, respectively. In comparison to the IgM ELISA reference test, the IgM component of RDTs showed a sensitivity of 40.0%, 50.3%, 47.3% and 20.0% respectively and specificity of 92.4%, 88.6%, 96.5%, and 92.2% respectively. Combining NS1 antigen and IgM antibody results led to sensitivities of 87.5%, 82.9%, 93.8% and 91.7% respectively, and specificities of 75.3%, 73.9%, 76.5%, and 80.0% respectively. INTERPRETATION & CONCLUSION: Though specificities were acceptable, the sensitivities of each test were markedly lower than manufacturers' claims. These results also support the added value of combined antigen-and antibody-based RDTs for the diagnosis of acute dengue