Search Results

You are looking at 21 - 30 of 129 items for :

  • All content x
Clear All

A szerzok laboratóriumi talajérleléses kísérletet állítottak be meszes Duna öntéstalajon különbözo elemi kén dózisok (0,1 g; 1,0 g; 2,5 g; 5,0 g; illetve 10 g/tenyészedény, azaz 50, 500, 1250, 2500 és 5000 kg ha-1) talajbeli oxidációjának vizsgálata céljából mutrágyázatlan, illetve NPK-mutrágyázott körülmények között. A 84 napos inkubációs periódus elteltével a talajok pH(H2O),pH(KCl) értékeit, valamint a talajokban mérheto, vízoldható szulfátion-koncentrációt elemezték. Az eredményeket varianciaanalízis és regressziószámítás segítségével értékelték.  Az elvégzett vizsgálatok alapján megállapították, hogy a mutrágyázatlan talajok különbözo elemi kén adagok hatására kialakult pH-értékei szignifikáns különbséget nem mutattak, míg a mutrágyázott kezelések esetén az emelkedo kéndózisok hatására bekövetkezo pH-csökkenés 0,1 %-os szignifikancia szinten általánosnak bizonyult. A talajok felveheto szulfátion-koncentrációja vélhetoen a kezelések, valamint a talajok mikrobiális tevékenységének hatására minden esetben nott. Az elemi kén adagok, valamint a talajok mért szulfátion-koncentrációinak 0,1 %-os szignifikancia szinten érvényesülo összefüggései azonban a talaj pH-értékeinek alakulásával bizonyítható kapcsolatot nem mutattak. A látszólagos ellentmondás hátterében számos biológiai, fizikai és kémiai tényezo állhat, melyek meghatározása a kapott összefüggések tisztázása szempontjából további vizsgálatok szükségességét veti fel.

Restricted access
Acta Alimentaria
Authors: J. Montiel-Ventura, J.J. Luna-Guevara, M.A. Tornero-Campante, A. Delgado-Alvarado, and M.L. Luna-Guevara

The aim was to examine conditions of convective drying and spray-drying to improve preservation of lycopene content in tomatoes. The weight, size, colour, pH and °Brix values were evaluated in fresh fruit (FF) and colour (L, a, b), hue, and chrome indices were analysed from dried tomatoes, too. Tomato paste was dried (40, 50, 60, and 80 °C with times of 540, 390, 270, and 240 min) under convection conditions and pulverized. In the encapsulation treatments core material with tomato powders of 50, 60, and 70%, shell solution of maltodextrin/gum arabic 1:1, flow rate of 4, 6, 9, and 12 ml min–1, and inlet air T of 160, 170, and 180 °C were used. The physicochemical properties of FF corresponded to a degree of ripeness for consumption. The a, a/b, and hue values of dried tomatoes at 50 °C significantly correlated to red colouring and higher lycopene content (47.98±1.49 mg/100 g). The encapsulation with 50% and 60% of tomato powders, 170 °C and 9 ml min–1 treatments increased lycopene contents to 10.41 mg/100 g, 10.20 mg/100 g, and 11.51 mg/100 g, respectively. The results demonstrated that the physicochemical and functional properties were influenced by drying conditions, providing useful information for increasing the stability of lycopene in dried tomatoes.

Open access
Acta Biologica Hungarica
Authors: Lili Kandra, Judit Remenyik, Gyöngyi Gyémánt, A. Lipták, A. Lipták, and A. Lipták

To elucidate how temperature effects subsite mapping of a thermostable a-amylase from Bacillus licheniformis (BLA), a comparative study was performed by using 2-chloro-4-nitrophenyl (CNP) b-maltooligosides with degree of polymerisation (DP) 4-10 as model substrates. Action patterns, cleavage frequencies and subsite binding energies were determined at 50 °C, 80 °C and 100 °C. Subsite map at 80 °C indicates more favourable bindings compared to the hydrolysis at 50 °C. Hydrolysis at 100 °C resulted in a clear shift in the product pattern and suggests significant differences in the active site architecture. Two preferred cleavage modes were seen for all substrates in which subsite (+2) and (+3) were dominant, but CNP-G1 was never formed. In the preferred binding mode of shorter oligomers, CNP-G2 serves as the leaving group (79%, 50%, 59% and 62% from CNP-G4, CNP-G5, CNP-G6 and CNP-G7, respectively), while CNP-G3 is the dominant hydrolysis product from CNP-G8, CNP-G9, and CNP-G10 (62%, 68% and 64%, respectively). The high binding energy value (-17.5 kJ/mol) found at subsite (+2) is consistent with the significant formation of CNP-G2. Subsite mapping at 80 °C and 100 °C confirms that there are no further binding sites despite the presence of longer products.

Restricted access

Abstract  

Studies were initiated to investigate the effect of the delivery mode of45Ca ions through guinea pig skin in vivo. Direct current (DC), pulsating current (PC) and a Bernard current form, the “courtes periodes” current profile (CP) were applied with the same current density (0.16 mA/cm2) and for the same duration (30 minutes). The45Ca ions were delivered from a Ca-bentonite patch radiolabeled with45Ca (a natural mineral clay rich in calcium, 50 mgCa/g). The total quantity of applied bentonite was 1.5g×10 days=15g.45Ca was counted in different biological samples of the animals. The delivery of45Ca ions into the body (systemic effect) is the highest when CP current is applied (6.87±0.95·10−12g/samples). The local effect appears to be more effective in case of DC current mode (5.89±0.12·10−12g/0.5g bone). Total calcium measurements proved that the result of transdermal radiocalcium delivery is not only an ion exchange process at the surface of the bone but a deposition of calcium ions into the hydroxiapatite matrix (the net calcium introduction, which represent the difference between the total calcium into the treated bone and total calcium into untreated bone varied from 15.52±2.42·10−3g/0.5g bone to 44.30±3.50·10−3g/0.5g bone). The results suggest that iontophoresis could be used to accumulate calcium into different target tissues using the appropriate current system.

Restricted access

Summary The present paper addresses the objective of developing forward indicators of research performance using bibliometric information on the UK science base. Most research indicators rely primarily on historical time series relating to inputs to, activity within and outputs from the research system. Policy makers wish to be able to monitor changing research profiles in a more timely fashion, the better to determine where new investment is having the greatest effect. Initial (e.g. 12 months from publication) citation counts might be useful as a forward indicator of the long-term (e.g. 10 years from publication) quality of research publications, but - although there is literature on citation-time functions - no study to evaluate this specifically has been carried out by Thomson ISI or any other analysts. Here, I describe the outcomes of a preliminary study to explore these citation relationships, drawing on the UK National Citation Report held by Evidence Ltd under licence from Thomson ISI for OST policy use. Annual citation counts typically peak at around the third year after publication. I show that there is a statistically highly significant correlation between initial (years 1-2) and later (years 3-10) citations in six research categories across the life and physical sciences. The relationship holds over a wide range of initial citation counts. Papers that attract more than a definable but field dependent threshold of citations in the initial period after publication are usually among the top 1& (the most highly cited papers) for their field and year. Some papers may take off slowly but can later join the high impact group. It is important to recognise that the statistical relationship is applicable to groups of publications. The citation profiles of individual articles may be quite different. Nonetheless, it seems reasonable to conclude that leading indicators of research excellence could be developed. This initial study should now be extended across a wider range fields to test the initial outcomes: earlier papers suggest the model holds in economics. Additional statistical tests should be applied to explore and model the relationship between initial, later and total citation counts and thus to create a general tool for policy application.

Restricted access

Sample mass/mg Water/mg Water mmol/g 10 −2 n -butanol/mg n -butanol/mmol/g 10 −2 Toluene/mg Toluene/mmol/g

Open access

Enterobacteriaceae /g m : <0.3, M : <10 Moulds /g <10 Yeasts

Restricted access

(PP4) produced by PKN Orlen (Poland) were used in this study. They were characterised by the following MFR indices: 2.4–3.2 g/10 min for Malen F-401, 11–16 g/10 min for Malen P S-702, 25 g/10 min Moplen HP-548R and 50 g/10 min for Moplen HP-648T

Open access

Super saturation ratio S = C / C * 303 K 308 K r */m (Δ G *)/10 −15 kJ

Restricted access

0.15 High density polyethylene: Eltex 4009 MFN 1325. Melt-flow index: 0.9 g/10 min (190 °C, 2.16 kg

Restricted access