High purity magnesium hydroxide has been synthesised from seawater with the addition of dolomite lime as reagent. High intensity ultrasound-assisted crystallization of magnesium hydroxide was carried ...out during precipitation with the intention to obtain fine particles of Mg(OH)2 as well as to prevent their agglomeration. Investigations were conducted on magnesium hydroxide samples in the form of sludge and voluminous powder. The composition, morphology, and properties of the product were determined by chemical, XRD, FTIR, and SEM/EDS analysis. The particle size distribution was detected by the laser light scattering method. The results showed that the mean particle size of magnesium hydroxide sludge was 5.75 µm, while voluminous powder was 7.58 µm. The morphology of magnesium hydroxide voluminous powder was in the form of aggregated filamentous (up to 300 nm in size) or flake structures.
Magnezijev hidroksid visoke čistoće sintetiziran je iz morske vode uz dodatak dolomitnog vapna. Ultrazvukom visokog intenziteta potpomognuta kristalizacija magnezijeva hidroksida tijekom precipitacije odvijala se u svrhu dobivanja što finijih čestica Mg(OH)2 i sprječavanja njihove aglomeracije. Ispitivanja su provedena na uzorcima magnezijeva hidroksida u obliku mulja i voluminoznog praha. Sastav, morfologija i svojstva dobivenog produkta analizirani su kemijskom, XRD, FTIR i SEM/EDS analizom. Raspodjela veličine čestica određena je metodom raspršenja laserskog svjetla. Rezultati ukazuju na to da je srednja veličina čestica magnezijeva hidroksida u obliku mulja 5,75 µm, dok je u voluminoznom prahu 7,58 µm. Morfologija voluminoznog praha magnezijeva hidroksida je u obliku aglomeriranih nitastih (duljine do 300 nm) i ljuspičastih struktura.
The aim of this work was to determine the effects of anion type (A), time (t), impeller off-bottom clearance (C/H) and solute concentration (c) on copper exchange on zeolite NaX in a batch stirred ...reactor. The experiments were carried out at constant temperature (300 K) and at the same impeller speed (250 rpm). The amount of exchanged copper at examined conditions was measured by UV/Vis spectrophotometer. In order to find the optimal process conditions for copper exchange on the basis of experimental data, Taguchi’s method for experimental design were used, applying larger-the-better approach. Beside the optimum experimental conditions this method allowed to define the influence of each process variable on the process conducted. Applied method has shown that the highest copper exchange is achieved at increased solute concentration, when sulphate anion was used, and impeller is positioned at standard position (C/H =0.33). It was also found that solute concentration and anion type have more pronounced impact on process investigated than impeller position and process duration (c > A > c/H > t). For the optimum experimental condition, kinetic data for copper exchange were obtained and tested using the Elovich and the Ritchie kinetic models.
Food allergy in children is increasing and the perception of food allergy among parents is even more common. In a questionnaire-based study of 702 children aged 6 to 48 months in four primary care ...settings, the aim was to determine the prevalence of perception vs. proven food allergy, parental anxiety and general pediatrician knowledge of food allergy. In 95/702 children (13.5%) parentally-reported food was associated reactions. IgE and/or skin prick test (SPT) and/or an open provocation test were performed in 48 (6.8%) and allergy was proven in 38 (5.4%) children. Discrepancy between parental perception and proven allergy is significant (p < 0.001), especially for food other than milk, egg and peanut (p < 0.001). Allergy to milk was the most common. Allergy to peanut was significantly more common in children ≥2 years (p < 0.05). Severe reactions occurred in 5/95 (5.2%) of all children and in 5/38 (13.1%) of allergic children, in 3/5 caused by peanut. Parents of children with proven allergy do not experience high degree of anxiety. The perception of food allergy among general pediatricians is limited, and in children with severe reactions precautionary measures and information to parents were insufficient. Parents and general pediatricians need additional education in food allergy.
SAŽETAK
UvodPandemija COVID-19 dovela je do izazova u liječenju bolesnika kojima je potrebna transplantacija krvotvornih matičnih stanica (KMS). Porastom broja oboljelih širom svijeta smanjila se ...dostupnost KMS-a zbog infekcije darivatelja i ograničenja u međunarodnom prometu. Sukladno tomu, uveden je niz mjera u cilju zaštite bolesnika i darivatelja te osiguravanja dostupnosti transplantata tijekom pandemije. Cilj rada bio je prikazati utjecaj pandemije COVID-19 na prikupljanje alogeničnih KMS-a u KBC-u Zagreb.
MetodeProvedena je retrospektivna analiza podataka za razdoblje od 1. ožujka 2020. do 30. lipnja 2021. Podatci su prikupljeni iz bolničkoga informacijskog sustava te zapisnika sa sastanaka Povjerenstva za liječenje transplantacijom KMS-a KBC-a Zagreb.
RezultatiU navedenom razdoblju prvenstveno su korištene KMS iz periferne krvi, osim u slučaju snažne indikacije za primjenu koštane srži (KS). Pripravci alogeničnih KMS-a su prije početka kondicioniranja krioprezervirani kako bi se osigurala raspoloživost prema planu liječenja. Kod 13 bolesnika se odustalo od prikupljanja KMS-a jer su dobili COVID-19. Alogenične KMS su prikupljene od srodnih i nesrodnih darivatelja iz Hrvatskog registra dobrovoljnih darivatelja KMS-a i Svjetskog udruženja darivatelja koštane srži za ukupno 135 bolesnika. Koštana srž je prikupljena za 12,5% bolesnika i svi pripravci su transplantirani. Šesnaest bolesnika je transplantirano s perifernim KMS umjesto KS. Transplantirano je 94,1% pripravaka perifernih KMS-a, od kojih je 17 transplantirano s odgodom zbog infekcije darivatelja i/ili bolesnika bolešću COVID-19 prije ili nakon prikupljanja KMS-a. Od ukupno 118 transplantata perifernih KMS-a, 100 (84,7%) ih je krioprezervirano u 540 vrećica. Sedam (5,9%) krioprezerviranih transplantata perifernih KMS-a nisu infundirani zbog progresije bolesti (5), infekcije primatelja bolešću COVID-19 (1) i loše vijabilnosti stanica (1).
ZaključakPandemija COVID-19 nepovoljno je utjecala na prikupljanje i transplantaciju KMS-a uz brojne organizacijske i logističke izazove. Krioprezervacija alogeničnih KMS-a omogućila je uspješno odvijanje transplantacijskog liječenja, iako je nažalost praćena rizikom da neki od tih pripravaka kasnije ne budu infundirani, što izlaže darivatelje riziku nepotrebnog prikupljanja i povećava troškove liječenja.
Acne vulgaris is a common chronic skin disorder of the pilosebaceous unit with a wide range of clinical presentations, which depend on the age of onset of acne, sex, family history of acne, and ...genetic factors, especially the genes affecting keratinization and desquamation. This retrospective study investigated pediatric acne using the patients' past medical history, with patients aged from newborns to 15 years of age. Acne were further stratified by 5 parameters: sex, age, family history, acne type, and localization. Our main aim was to investigate the possible association between selected parameters and the presence or absence of family history of acne. We did not find statistically significant correlation between sex, age of onset, and positive family history of acne. Furthermore, we did not find any association between age of onset and family history according to family members (mother/father/brother or sister). However, we found statistically significant correlation between sex and type of acne. This retrospective analysis of pediatric acne in Croatia did not reveal statistically significant correlation between positive family history and sex, age of onset, and clinical type of acne. In analyzing the correlation between family history and localization of acne, however, we found that the number of patients with acne localized on both the face and trunk and positive family history was statistically significant higher than expected.
Magnezijev hidroksid visoke čistoće sintetiziran je iz morske vode uz dodatak dolomitnog vapna. Ultrazvukom visokog intenziteta potpomognuta kristalizacija magnezijeva hidroksida tijekom ...precipitacije odvijala se u svrhu dobivanja što finijih čestica Mg(OH)2 i sprječavanja njihove aglomeracije. Ispitivanja su provedena na uzorcima magnezijeva hidroksida u obliku mulja i voluminoznog praha. Sastav, morfologija i svojstva dobivenog produkta analizirani su kemijskom, XRD, FTIR i SEM/EDS analizom. Raspodjela veličine čestica određena je metodom raspršenja laserskog svjetla. Rezultati ukazuju na to da je srednja veličina čestica magnezijeva hidroksida u obliku mulja 5,75 µm, dok je u voluminoznom prahu 7,58 µm. Morfologija voluminoznog praha magnezijeva hidroksida je u obliku aglomeriranih nitastih (duljine do 300 nm) i ljuspičastih struktura.
Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna .
The aim of this work was to determine the effects of anion type (A), time (t), impeller off-bottom clearance (C/H) and solute concentration (c) on copper exchange on zeolite NaX in a batch stirred ...reactor. The experiments were carried out at constant temperature (300 K) and at the same impeller speed (250 rpm). The amount of exchanged copper at examined conditions was measured by UV/Vis spectrophotometer. In order to find the optimal process conditions for copper exchange on the basis of experimental data, Taguchi’s method for experimental design were used, applying larger-the-better approach. Beside the optimum experimental conditions this method allowed to define the influence of each process variable on the process conducted. Applied method has shown that the highest copper exchange is achieved at increased solute concentration, when sulphate anion was used, and impeller is positioned at standard position (C/H =0.33). It was also found that solute concentration and anion type have more pronounced impact on process investigated than impeller position and process duration (c > A > c/H > t). For the optimum experimental condition, kinetic data for copper exchange were obtained and tested using the Elovich and the Ritchie kinetic models.
Acne vulgaris is a common chronic skin disorder of the pilosebaceous unit with a wide range of clinical presentations, which depend on the age of onset of acne, sex, family history of acne, and ...genetic factors, especially the genes affecting keratinization and desquamation. This retrospective study investigated pediatric acne using the patients’ past medical history, with patients aged from newborns to 15 years of age. Acne were further stratified by 5 parameters: sex, age, family history, acne type, and localization. Our main aim was to investigate the possible association between selected parameters and the presence or absence of family history of acne. We did not find statistically significant correlation between sex, age of onset, and positive family history of acne. Furthermore, we did not find any association between age of onset and family history according to family members (mother/father/brother or sister). However, we found statistically significant correlation between sex and type of acne. This retrospective analysis of pediatric acne in Croatia did not reveal statistically significant correlation between positive family history and sex, age of onset, and clinical type of acne. In analyzing the correlation between family history and localization of acne, however, we found that the number of patients with acne localized on both the face and trunk and positive family history was statistically significant higher than expected.
Old people living alone: consequences and prevention
Important findings in the field of solitary life in old age and the problem of loneliness are presented. Difficulties experienced by old people ...due to loneliness should not be neglected and their impact on their physical and mental health and general wellbeing needs to be addressed. Therefore some interventions are described that proved to be effective in preventing negative consequences of loneliness among the elderly. As the social network is very important for the health of the old, the most successful interventions are those based on strengthening the social support of old people (for example cooperation within associations, providing support to others, multigenerational households).
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