• Title/Summary/Keyword: sodium

Search Result 9,832, Processing Time 0.05 seconds

Studies on the Comparative Analysis of Immunofunction of Agaricus blazei Murill Cultivated with Fermented Media Containing Pueraria thunbergiana (칡혼합 발효배지로 생산된 신령버섯의 면역기능성 비교 분석에 관한 연구)

  • 김주남;서정식;박동철
    • Food Science and Preservation
    • /
    • v.9 no.1
    • /
    • pp.114-119
    • /
    • 2002
  • This research was performed to investigate the immnomodulative effects of ploysaccharides extracted from the fruiting body of Agarcus blazei cultivated with the media which are fermented with sugar cane bagasse containing Pueraria thunbergiana in open-air storage. In MTT test, methanol extracts from the fruiting body of A. blazei cultivated with P. thunbergiana media showed in colon carcinoma line(HT29) by 1.5∼3.5 fold and human heptoma cell line (HepG2) by 1.3 ∼2.4 fold antitumor activites compared to two types media (rice straw plus sugar cane bagasse, rice straw only) often used in the fauns. To clarify the antimutagenic principles, three extracts, Ab-l, Ab-2 and Ab-3, were separated by the solvent fractionations such as hot water, cold & hot sodium hydroxide respectively, and their antimutagenic effects was determined against N-methyl-N'-nitro-N-cnitrso-guanidine(MNNG) using Salmonella typhymurium. There was no significant differencies of inhibition levels among the used media, but Ab-3 tractions still showed a high antimutagenicity in the Ames test regardless of cultivating areas or media. To prove the cell immunofunction, nitric oxide (NO) produced from Raw 264.7 matrophage cultured with three fractions (Ab-l, Ab-2, Ab-3) was measured, and showed generally increase about 45 ∼58 percent compared to another two media (rice straw plus sugar cane bagasse, rice straw only), in the fraction of hot alklai extracts of the fruiting body cultivated with P. thunbergiana, which means that the media selection could be very important factors for improving medicinal effects in agaricus blazei fruiting body.

Comparison of quality changes in brined cabbage with deep sea water salt and a commercial brined cabbage product (해양심층수염 절임배추와 시판 절임배추의 품질변화 비교)

  • Lim, Ji Hoon;Jung, Jee Hee;Kim, Dong Soo;Kim, Young Myoung;Kim, Byoung Mok
    • Food Science and Preservation
    • /
    • v.21 no.5
    • /
    • pp.676-687
    • /
    • 2014
  • This study investigated the quality changes in cabbage brined with deep sea water salt and in a commercial brined cabbage product. The subject cabbages were separated into two groups: those manufactured in the Lab (ML) and the commercial brined cabbage product (CP). Each group had three brining treatments: with sun-dried salt (S, CS), refined salt (R, CR), and deep sea water salt (D, CD). The salinity level of the ML group was 2.1~2.3%, higher than that of the CP group (1.1~1.5%). The total plate count (TPC) was detected as 5.0 log CFU/g with the S, R, and D treatments at Day 7, but the growth rate of the TPC with the CS, CR, and CD treatments was faster than that with the S, R, and D treatments (6.9~7.7 log CFU/g). A lactic acid bacteria (LAB) level of 5.0~6.6 log CFU/g was also detected in the S, R, and D samples, but only 7.0~7.6 log CFU/g was detected in the CP groups at Day 14. The instrumental hardness levels of the cabbage brined with the deep sea water salts (D and CD) were 3,971 g and 3,932.4 g, respectively, which were significantly higher than those of the samples that were salted with sun-dried salt and refined salt (p<0.05). As for the sensory attributes, S, D, and CD maintained their marketability scores until the end of the storage period for all the properties. CD presented the highest total free amino acid (478.9 mg%), glutamic acid (107.0 mg%), citric acid (428 mg%), and sodium (189 ppm) contents.

Three Crystal Structures of Dehydrated Partially $Co^{2+}-Exchanged$ Zeolite A Treated with Potassium Vapor (부분적으로 코발트 이온으로 치환한 제올라이트 A를 진공 탈수한 후 칼륨 증기로 반응시킨 3개의 결정구조)

  • Jeong Mi Suk;Jang Se Bok
    • Korean Journal of Crystallography
    • /
    • v.15 no.2
    • /
    • pp.59-68
    • /
    • 2004
  • Three crystal structures of dehydrated partially $Co^{2+}-exchanged$ zeolite A treated with 0.6 Torr of K at $300^{\circ}C$ (for 12 hrs, 6 hrs, and 2 hrs) vapor have been determined by single-crystal X-ray diffraction techniques in the cubic space group Pm3m at 21(1)$^{\circ}C(a=12.181(1)\;{\AA},\;a=12.184(1)\;{\AA},\;and\;a=12.215(1)\;{\AA})\;respectively)$. Their structures were refined to the final error indices, R(weight) of 0.090 with 10 reflections, 0.091 with 82 reflections, and 0.090 with 80 reflections, respectively, for which $1>\sigma(I)$. In each structure, all four $Co^{2+}$ and four $Na^+$ ions to be reduced by K atoms. The cobalt and sodium atoms produced are no longer found in the zeolite. K species are found at five different crystallographic sites: three $K^+$ ions lie at the planes of 8-rings, filling that position, ca. 11.5 K^+$ ions lie on threefold axes, ca. 4.0 in the large cavity and ca. 4.0 in the sodalite cavity, and ca. 0.5 $K^+$ ion is found near a 4-ring. ca. three $K^0$ atoms are found deep into the large cavity on threefold axes. In these structures, crystallographic results show that cationic tetrahedral $K_4$ (and/or triangular $K_3$) clusters have formed in the sodalites of zeolite A. The $K_4$ and/or $K_3$ clusters coordinate trigonally to three oxygens of a six-oxygen ring. The partially reduced ions of these clusters interact primarily with oxygen atoms of the zeolite structure rather than with each other. ca. 14.5K species are found per unit cell, more than the twelve $K^+$ ions needed to balance the anionic charge of zeolite framework, indicating that sorption of $K^0$ has occurred. The three $K^0$ atoms in the large cavity are closely associated with three out of four $K^+$ ions in the large cavity to form $K_7^{4+}$ clusters. The $K_7^{4+}$ cluster not interacts primarily with framework oxygens.

A Study on Bone Formation & Osteoporosis by Taeyoungion-Jahage Extracts

  • Kim, Yi-Geun;Seong, Jun-Ho;Kim, Dong-Il;Lee, Tae-Kyun;Kim, Jun-Ki;Park, Young-Duck
    • The Journal of Korean Obstetrics and Gynecology
    • /
    • v.15 no.4
    • /
    • pp.45-60
    • /
    • 2002
  • Mouse calvarial osteoblast cells were isolated and cultured. To examine whether the cells produce active gelatinases in culture medium or not,the cells were analyzed using by zymograsphic analysis on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). We show that mouse calvarial osteoblasts in culture constitutively synthesize progelatinase- A. Then, mouse osteoblasts, which were stimulated by PTH, $1,25(OH)_2D_3$, mononuclear cell conditioned medium (MCM) and IL-1 as bone resorption agent's, showed increased collagenolysis by producing the active gelatinase. However, treatment of indomethacin and dexamethasone significantly decreased those effects of collagenolysis in mouse osteoblastic cells. On the other hand, IL-1 in stimulating bone resorption was examined using fetal mouse long bone organ culture. IL-1 stimulated bone resorption and produced marked resorption when present simultaneously. Furthermore, when it was examined the effects of indomethacin and dexamethasone on the dose dependent responses of $IL-1{\alpha}$, indomethacin and dexametasone produced a rightward shift in the IL-1 dose response curve. The results of in vitro cytotoxicities showed that Taeyoungjon-Jahage water extracts(T.Y.J-J.H.G extracts) have no any cytotoxicities in concentrations of $1-200\;{\mu}g/ml$ and furthermore there is no any cytotoxicity even in concentration of $300\;{\mu}g/ml$ on mouse calvarial bone cells. T.Y.J.-J.H.G. extracts had protective activity against PTH (2 units/mI), or MCM (5%, v/v), or $rhIL-1{\alpha}$ (1 ng/mI) or $1,25(OH)_2D3$ (10 ng/ml) , $IL-1{\alpha}$ and $IL-1{\beta}-induced$ collagenolysis in the mouse calvarial cells. Pretreatment of the T.Y.J.-J.H.G.extracts for 1 h, which by itself had little effect on cell survival, did not enhance the collagenolysis, nor significantly reduced the collagenolysis by pretreatment. Furthermore. the medicinal extracts were shown to have the protective effects against collagenolysis induced by $IL-1{\alpha}$ and $IL-1{\beta}$. Pretreatment of the extracts for 1 h significantly reduced the collagenolysis. Interestingly, the T.Y.J.-J.H.G. extracts were shown to have the inhibiting effects against gelatinase enzyme and processing activity induced by the bone resortion agents of PTH, $1,25(OH)_2D_3$, $IL-1{\beta}$ and $IL-1{\alpha}$, with strong protective effect in pretreatment with the extracts. T.Y.J.-J.H.G. extracts were shown to have the inhibiting effects against $IL-1{\alpha}-$ and $IL-1{\beta}-stimulated$ bone resorption and the effect of the pretreatment with a various concentrations of the medicinal extracts were significant. The inhibition extent and phenomena of IL-1 stimulated bone resorption by nonsteroidal anti-inflammatory agents of indomethacin and dexamethasone were similar to those obtained by T.Y.J.-J.H.G. extracts treatment in the mouse calvarial tissue culture system. These results indicated that the T.Y.J.-J.H.G.-water extracts are highly stable and applicable to clinical uses in osteoporosis.

  • PDF

Effects of UF Resin and Taro Adhesive Mixture on Plywood Bonding Strength (요소수지(尿素樹脂)와 토란접착제(土卵接着劑) 혼용(混用)이 합판(合板)의 접착력(接着力)에 미치는 영향(影響))

  • Lee, Phil-Woo;Park, Heon
    • Journal of the Korean Wood Science and Technology
    • /
    • v.12 no.1
    • /
    • pp.3-10
    • /
    • 1984
  • Taro-UF mixed type resin system was developed for gluing plywoods. The taro adhesive that was activated with sodium hydroxide was mixed with the definite ratios of UF resin adhesive. At the sametime, wheat-UF mixed type resin was also applied with the same method as taro-UF mixed type resin The mixing ratios of taro or wheat adhesive: UF resin were 0:100, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 80:20, and 100:0 by weight. In addition, the UF resins extended with wheat powder at the extending ratios of wheat powder UF resin, 10:90, 20:80, 30:70, 40:60, and 50:50 by weight, were also used. The dry and wet shear strengths of the plywoods of 30:70 (taro adhesive : UF resin) mixing ratio were highest. The dry shear strengths of the plywoods manufactured with the UF resin-mixing taro adhesive were higher than those of the plywoods with the UF resin-mixing wheat adhesive at 10:90, 20:80, 30:70, 40:60, 50:50, and 60:40 (taro or wheat adhesive: UF resin) mixing ratios. At all mixing ratios, the wet shear strengths of the plywoods manufactured with the UF resin-mixing taro adhesive were higher than those of the plywoods with the UF resin-mixing wheat adhesive. The dry and wet shear strengths of the plywoods manufactured with the UF resin-mixing wheat adhesive were higher than those of the plywoods with the wheat powder-extending UF resin at the mixmg ratios, 10:90, 20:80, 30:70, and 40:60 (wheat adhesive or wheat powder: UF resin). So, it was found that the plywoods manufactured with the UF resin-mixing taro adhesive and the UF resin mixing wheat adhesive had better shear strength than the plywoods with the wheat powder-extending UF resin. It was because the taro adhesive and wheat adhesive themselves took the bonding properties after being activated with alkali.

  • PDF

Study on Affecting Variables Appearing through Chemical Pretreatments of Poplar Wood (Populus euramericana) to Enzymatic Hydrolysis (이태리 포플러의 화학적 전처리 공정을 통한 효소가수분해 영향 인자 분석)

  • Koo, Bon-Wook;Park, Nahyun;Yeo, Hwanmyeong;Kim, Hoon;Choi, In-Gyu
    • Journal of the Korean Wood Science and Technology
    • /
    • v.37 no.3
    • /
    • pp.255-264
    • /
    • 2009
  • To evaluate the effects of chemical pretreatments of lignocellulosic biomass on enzymatic hydrolysis process, Populus euramericana was pretreated for 1 hr with 1% sulfuric acid ($H_2SO_4$) at $150^{\circ}C$ and 1% sodium hydroxide (NaOH) at $160^{\circ}C$, respectively. Before the enzymatic hydrolysis, each pretreated sample was subjected to drying process and thus finally divided into four subgroups; dried or non-dried acid pretreated samples and dried or non-dried alkali pretreated samples and chemical and physical properties of them were analyzed. Biomass degradation by acid pretreatment was determined to 6% higher compared to alkali pretreatment. By the action of acid ca. 24.5% of biomass was dissolved into solution, while alkali degraded ca. 18.6% of biomass. However, reverse results were observed in delignification rates, in which alkali pretreatment released 2% more lignin fragment from biomass to the solution than acid pretreatment. Unexpectedly, samples after both pretreatments were determined to somewhat higher crystallinity than untreated samples. This result may be explained by selective disrupture of amorphous region in cellulose during pretreatments, thus the cellulose crystallinity seems to be accumulated in the pretreated samples. SEM images revealed that pretreated samples showed relative rough and partly cracked surfaces due to the decomposition of components, but the image of acid pretreated samples which were dried was similar to that of the control. In pore size distribution, dried acid pretreated samples were similar to the control, while that in alkali pretreated samples was gradually increased as pore diameter increased. The pore volume which increased by acid pretreatment rapidly decreased by drying process. Alkali pretreatment was much more effective on enzymatic digestibility than acid pretreatment. The sample after alkali pretreatment was enzymatically hydrolyzed up to 45.8%, while only 26.9% of acid pretreated sample was digested at the same condition. The high digestibility of the sample was also influenced to the yields of monomeric sugars during enzymatic hydrolysis. In addition, drying process of pretreated samples affected detrimentally not only to digestibility but also to the yields of monomeric sugars.

Effects of Chitosan and Organic Acid Salts on the Shelf-life and Pectin Fraction of Kimchi during Fermentation (키토산과 유기산염 첨가가 배추김치의 저장성과 펙틴분획에 미치는 영향)

  • 이지선;이혜준
    • The Korean Journal of Food And Nutrition
    • /
    • v.13 no.4
    • /
    • pp.319-327
    • /
    • 2000
  • This study was conducted to prolong the edible period of Kimchi by adding chitosan (0.25, 0.5%) and sodium salts of various organic acids(0.01~0.04M citrate, malate, lactate) . The edible period was estimated by measuring changes in pH. titratable acidity(TA), PH/TA ratio, ascorbic acid content and pectin fraction during Kimchi fermentation at 2$0^{\circ}C$. The results were compared by estimating the maturity of Kimchi fermentation. Kimchi with the chitosan showed higher pH and titratable acidity throughout the fermentation period than that without chitosan. The pH decreased during the fermentation in the order of control, 0.25% chitosan, 0.5% chitosan, 0.5% chitosan+Na-citrate, 0.5% chitosan+Na-malate and 0.5% chitosan+Na-lactate. But the titratable acidity increased in the order of control, 0.5% chitosan+Na-malate, 0.25% chitosan. 0.5% chitosan+Na-citrate, 0.5% chitosan and 0.5% chitosan+Na-lactate. The PH/TA ratio decreased in the order of control, 0.25% chitosan, 0.5% chitosan+Na-malate, 0.5% chitosan, 0.5% chitosan+Na-citrate and 0.5% chitosan+Na-lactate. Ascorbic acid content in Kimchi was the highest at the 3rd day and then decreased during fermentation. Ascorbic acid content in Kimchi containing 0.5% chitosan and organic acid salts was higher than others. Alcohol insoluble solids( AIS ) in Kimchi decreased during fermentation in the order of control, 0.25% chitosan, 0.5% chitosan, 0.5% chitosan+Na-palate. 7.5% chitosan+Na-lactate and 0.5% chitosan+Na-citrate. During fermentation, hot water soluble pectin (HWSP) of control increased, whereas HCI soluble pectin (HCISP) decreased. By addition of chitosan, however, the results became reverse. Chitosan addition appeared to be effective in improving preservation quality of Kimchi during fermention. The edible period become extended by using chitosan plus organic acids instead of using chitosan only. Overall. addition of 0.5% chitosan+Na-lactate seemed most effective in prolonging the edible periods during Kimchi fermentation.

  • PDF

Salinity and Consumption Patterns of Kimchi and Soup${\cdot}$Stew in Jeonju Area (전주지역 김치와 국${\cdot}$찌개의 염도 및 섭취실태)

  • Song, Mi-Ran;Lee, Kyung-Ja
    • Korean journal of food and cookery science
    • /
    • v.24 no.1
    • /
    • pp.84-91
    • /
    • 2008
  • In this study, Kimchi, soup and stew samples were collected from May to June, 2007, in the Jeonju area, and their salinity levels were analyzed. In addition, housewives were surveyed via questionnaire to assess food behaviors and consumption patterns. The average salinity of the Kimchi samples was $2.0{\pm}0.5%$. The average salinity of the soup/stew samples was $1.0{\pm}0.3%$ in the broth portion and $0.8{\pm}0.3%$ in the homogenized mixture of both broth and solids. The average salinity of all types of soup was $0.9{\pm}0.3%$, and that for stews was $1.1{\pm}0.3%;$ the average salinity of the stew was significantly higher than that of the soup (p<0.001). Beanpaste soup had a significantly higher average salinity $(1.0{\pm}0.3%)$ than clear soup $(0.8{\pm}0.3%)$ (p<0.05). The Food behavior scores of the respondents, with regard to sodium intake and salty taste preference, showed significant positive correlations to the salinity of the soup and stew samples (p<0.01). The consumption patterns of the Kimchi and soup/stews were also analyzed to determine whether there was a relationship to the saltiness of the food samples. The respondents were divided into two groups for each food category: Kimchi groups of below 2.0% salinity and above 2.1% salinity, soup/stew groups of below 0.8% salinity and above 0.9% salinity. The below 0.8% salinity soup/stew group used salt or soy sauce in meals significantly less frequently (p<0.01) than the above 0.9% salinity group. The lower salinity Kimchi and soup/stew groups gave significantly higher scores regarding answers that their Kimchi was 'bland' (p<0.05). The types of frequently consumed Kimchi were determined as Korean cabbage, Welsh, wild greens, radish, KKak Du Ki, and Yol Mu Kimchi. When compared to the above 2.1% salinity Kimchi group, the below 2.0% salinity Kimchi group gave higher scores regarding answers that they consumed 'more than half the broth in the bowel' and also gave significantly higher (p<0.01) scores in answering that they consumed only the solid ingredients, leaving the broth.

Experimental Studies on the Efficiency of the Injection of Mokhyangsunkisan extract, Mokhyangsunkisan plus Rheum undulatum L. extract and Palmisunkisan extract (목향순기산(木香順氣散) 수침액(水鍼液)의 효능(效能)에 관(關)한 실험적(實驗的) 연구(硏究))

  • Kim, Young-Tae;Jeong, Hee-Jae;Jung, Sung-Ki;Rhee, Hyung-Koo
    • The Journal of Korean Medicine
    • /
    • v.17 no.1 s.31
    • /
    • pp.280-301
    • /
    • 1996
  • This thesis is on the effects of the Injections of Mokhyangsunkisan extract, Mokhyangsunkisan plus Rheum undulatum L. extract and Palmisunkisan extract clinical experiments wre done with medicines to research their analgesic and anti-convulsive action and their efficiency on $O_3$ and Xylene-poisoned lung damage and the pulmonary thromboembolism of rats and mice. The results are as follows; 1. As to the analgesic action, each Injection of Mokhyangsunkisan extract, Mokhyangsunkisan plus Rheum undulatum L. extract and Palmisunkisan extract had significant effects. Among them the Injection of Mokhyangsunkisan plus Rheum undulatum L. extract had the highest effect. 2. As to the anti-convulsive action, each Injections of Mokhyangsunkisan extract and Palmisunkisan extract had significant effects whereas that of the Injection of Mokhvangsunkisan plus Rheum undulatum L. extract had no effect. 3. In the frsearch of the Lung TBA values of $O_3$-poisoned rats. each Injection of Mokhyangsunkisan extract and Palmisunkisan extract had significant effects whereas that of the Injection of Mokhyangsunkisan plus Rheum undulatum L. extract had no effect. 4. None of the Injection of Mokhyangsunkisan extract, Mokhyangsunkisan plus Rheum undulatum L, extract and Palmisunkisan extract had significant effects in the experiments about the variation of the $Na^+$ contents and $K^+$ contents in the serum electrolytes of the $O_3$-poisoned rats. 5. In the research of the Lung TBA values of Xylene-poisoned rats all the three Injections had prominent effects. 6. In the research of the Lung weight in Xylene-poisoned rats each Injections of Mokhyangsunkisan extract and Palmisunkisan extract had significant effects whereas that of the Injection of Mokhyangsunkisan plus Rheum undulatum L. extract had no effect. 7. In the experiments about the variation of the $Na^+$ contents in the serum electrolytes of the Xylene-poisoned rats the Injection of Mokhyangsunkisan extract had a significant effect whereas those of the Injections of Mokhyangsunkisan plus Rheum undulatum L. extract and Palmisunkisan extract had no significant effects. 8. None of the Injection of Mokhyangsunkisan extract, Mokhyangsunkisan plus Rheum undulatum L. extract and Palmisunkisan extract had significant effects in the experiments about the variation of the $K^+$ contents in the serum electrolytes of the Xylene-poisoned rats. 9. All the three Injections had prominent death-repressive effects on the pulmonary thromboembolism induced by Sodium Arachidonate. 10. Each Injection of Mokhyangsunkisan extract and Palmisunkisan extract had death-repressive effects on the pulmonary thromboembolism induced by ADP, whereas the Injection of Mokhyangsunkisan plus Rheum undulatum L. extract had a feeble death-repressive effect By all results of the clinical experiments. the following conclusions are drown; Each Injection of Mokhyangsunkisan extract and Palmisunkisan extract has analgesic and anti-convulsive effects and is also effective for the $O_3$ and Xylene-poisoned Lung damage and pulmonary thromboembolism of rats and mice. The Injection of Mokhyangsunkisan plus Rheum undulatum L. extract has on analgesic effect and is also effective for the pulmonary thromboembolism. Especially its analgesic effect is prominent. Therefore, each Injection of Mokhyangsunkisan extract and Palmisunkisan extract can be used for injection to improve the pulmonary functions whereas the Injection of Mokhyangsunkisan plus Rheum undulatum L. extract is partly effective for the improvement of the pulmonary function. In view of the results so far achieved, fluid acupuncture therapy can be applied as well as traditional way of oral administration of the decoction.

  • PDF

Comparison of clinical and laboratory characteristics in children with type 1 diabetes according to pancreatic autoantibodies (췌장 자가 항체 유무에 따른 제 1형 당뇨병의 임상 및 검사 소견의 비교)

  • Choi, Ji Hae;Kim, Min Sun;Kim, Chan Jong;Kim, Jong Duk;Lee, Dae-Yeol
    • Clinical and Experimental Pediatrics
    • /
    • v.53 no.3
    • /
    • pp.414-419
    • /
    • 2010
  • Purpose : The purpose of this study was to determine whether there is any difference in the clinical and laboratory characteristics of patients with autoantibody-positive and patients with autoantibody-negative type 1 diabetes at initial presentation. Methods : We analyzed 96 patients under 18 years of age with newly diagnosed type 1 diabetes. One or both of the pancreatic autoantibodies-glutamic acid decarboxylase autoantibodies (GADA) and insulin autoantibody (IAA)-were measured in all patients, and we reviewed clinical and laboratory characteristics according to the presence of these autoantibodies. Results : GADA was examined in 48 of 87 patients, and 55.2% of patients were positive. IAA was checked in 88 patients, and 39.8% were positive. Both GADA and IAA were measured in 83 patients, and 22.8% had both antibodies. The patients who had one or both autoantibodies (autoantibody-positive group) were younger than those not having any autoantibody (autoantibody-negative group). The autoantibody-positive group had lower BMI, corrected sodium level, and serum effective osmolarity, compared to the autoantibody-negative group (P <0.05). Similar differences were found between the GADA-positive and GADA-negative groups. However, there were no significant differences between the IAA-positive and IAA-negative groups. Conclusion : The prevalence of pancreatic autoantibodies was significantly higher in the under-6 years age group than in the other age groups. These findings suggest that measurement of autoantibodies at the initial diagnosis of diabetes is very useful for detecting immune-mediated type 1 diabetes and providing intensive insulin therapy, especially in younger children.