Understanding of photosynthesis concepts related to students’ age

In Croatian schools, the complex photosynthesis concept is presented several times during primary and secondary school, each time with more detail. The problems in understanding photosynthesis processes are known from many previous studies and our own research ; thus we aimed to investigate how the students’ understanding of the basic photosynthesis concepts increases during the schooling period, and is it enhanced by gradual introduction of new contents. The present study was conducted on 269 students from 6 schools and 35 students preparing to be biology teachers. To test the students’ conceptual understanding, we implemented a question about the trends of O2 and CO2 gas concentrations during the night, which was expected to lead students to a correct explanation of photosynthesis, including the issues of the plants’ respiration and the absence of photosynthesis. Students of all age groups gave mainly incomplete explanations. The best result was achieved by the youngest participants in the age of 11, who have relied on the freshly acquired and well trained, but reproductive knowledge. Older students’ answers (aged 15, 17 and 22), which include more detail about the light-dependent and light-independent reactions, suggested that they developed misconceptions such as the belief that “oxygen is produced in Calvin cycle during the night” and that “CO2 converts to O2”. Student's explanations indicate the consistency of their understanding of the process, which does not change with gradual introduction of new contents as they are older. The observed misunderstanding could be linked to the cumulative introduction of the complex theoretical contents, but excluding research- based learning, as well as to inadequate time dedicated to establishing connections between students’ pre-conceptions and novel information. Our research results might be a strong argument supporting the upcoming change in the national curriculum

THE POSSIBILITY OF APPLYING NEAT METALWORKING OILS FOR CYLINDER LINER HONING

Sažetak Honanje ili vlačno glačanje je postupak kojim obrađujemo najfinije površine metala radi postizanja zahtijevane točnosti i kvalitete obrađenih površina. Samo honanje kao i procesi struganja, glodanja, brušenja, tj. rezno uobličavanje metalnih materijala u svom se djelovanju ograničava na relativno tanak površinski sloj izratka i uglavnom izaziva hladnu plastičnu deformaciju, ali ne utječe dalekosežno na strukturu i svojstva materijala. Pri izvođenju procesa honanja vrlo je bitno da se radna površina oplahuje znatnim količinama sredstava za hlađenje i podmazivanje. Radnu površinu valja hladiti da ne bi došlo do promjene strukture zbog procesa rekristalizacije i otpuštanja. Osim toga, ispiranjem se odvodi metalna prašina nastala honanjem te iščupana zrnca s bruseva. Danas su istraživanja na ovom području usmjerena na primjenu novih sredstava za hlađenje i podmazivanje. Na temelju ekonomske i ekološke analize i analize kvalitete postupka honanja pri primjeni sredstava za hlađenje i podmazivanje na osnovi mineralnih ulja i uz sadržaj različitih tipova aditiva, u radu je ispitivana mogućnost primjene novih ulja pri honanju košuljica cilindara.Abstract Honing is a procedure treating the finest metal surfaces in order to achieve the required precision and quality of treated surfaces. Honing itself, as well as proceses of grating, milling, grinding, i.e. using cutting for the shaping of metal materials, is in its activity limited to a relatively thin surface layer of the workpiece, mostly causing cold plastic deformation, without any long-term impacts on either the structure or properties of the material. When performing the process of honing, it is extremely important that the working surface be washed by considerable volumes of the cooling and lubrication agents. The working surface needs to be cooled, so as not to cause any structural change due to the processes of recrystallization and release. Apart from that, rinsing takes away the metal dust generated by honing, as well as the pulled out grinding wheel grains. Research in this area is today oriented towards applying new cooling and lubricating agents. Based on economic and environmental analysis, as well as that of the quality of honing procedure when applying cooling and lubricating agents based on mineral oils, containing various types of additives, the paper also considers the possibility of applying new oils for the honing of cylinder bores

Klinički prikaz genitourinarne tuberkuloze sa sumnjom na abdominalnu neoplazmu

Genital tuberculosis is a rare and unexpected disease in European countries including Croatia. Diagnosis of female genital tract tuberculosis is challenging and is rarely pin-pointed by clinical symptoms because of their low specificity. The authors decided to present a case of genitourinary tuberculosis in a young, immunocompetent fertile woman with high clinical suspicion of abdominal tumor mass. Although considered a desease of the past, rare clinical presentation of genital tuberculosis should be expected and taken into account.Genitalna tuberkuloza rijetka je i neočekivana bolest u zemljama Europske unije uključujući i Hrvatsku. Postavljanje dijagnoze tuberkuloze genitalnog sustava otežano je nespecifičnim simptomima. Prikazujemo slučaj genitourinarne tuberkuloze kod mlade imunokompetentne žene generativne dobi gdje je klinička dijagnoza upućivala na abdominalnu neoplazmu. U vremenu velikih društvenih promjena prisutnih posljednjih godina rijetke kliničke prezentacije tuberkuloze i dalje su moguće kao diferencijalna dijagnoza

Laparoskopska ezofagomiotomija nakon neuspješne pneumatske dilatacije u bolesnika s idiopatskom ahalazijom

Achalasia is a relatively uncommon gastrointestinal disorder characterized by the absence of normal peristalsis of the esophagus and markedly diminished or absent relaxation of the lower esophageal sphincter during swallowing, caused by degenerative changes of parasympathetic innervation. All treatment modalities are palliative and include drug administration, endoscopic injection of botulinum toxin into the lower esophageal sphincter, pneumatic balloon dilatation, and surgery. Surgery offers the best long term results and may be performed as an open or endoscopic procedure, the latter yielding excellent results accompanied by all well-known advantages of minimally invasive surgery. Presentation is made of a patient with esophageal achalasia who was treated with balloon dilatation and laparoscopic esophagomyotomy.Ahalazija je relativno rijedak poremećaj probavnog sustava kod kojega je odsutna normalna peristaltika jednjaka, te je znatno smanjeno ili odsutno opuštanje donjeg ezofagusnog sfinktera kod gutanja, što je uzrokovano degenerativnim promjenama parasimpatetične inervacije. Svi oblici liječenja su palijativni, a uključuju medikamentnu terapiju, endoskopsko ubrizgavanje toksina botulina u donji ezofagusni sfinkter, pneumatsku dilataciju balonom i kirurško liječenje. Kirurški pristup pruža najbolje dugotrajne rezultate, a može se izvesti kao otvoreni zahvat ili endoskopski zahvat koji daje odlične rezultate praćene svim dobro poznatim prednostima minimalno invazivne kirurgije. Opisan je slučaj bolesnika koji je liječen dilatacijom balonom i laparoskopskom ezofagomiotomijom

Laparoskopska ezofagomiotomija nakon neuspješne pneumatske dilatacije u bolesnika s idiopatskom ahalazijom

Achalasia is a relatively uncommon gastrointestinal disorder characterized by the absence of normal peristalsis of the esophagus and markedly diminished or absent relaxation of the lower esophageal sphincter during swallowing, caused by degenerative changes of parasympathetic innervation. All treatment modalities are palliative and include drug administration, endoscopic injection of botulinum toxin into the lower esophageal sphincter, pneumatic balloon dilatation, and surgery. Surgery offers the best long term results and may be performed as an open or endoscopic procedure, the latter yielding excellent results accompanied by all well-known advantages of minimally invasive surgery. Presentation is made of a patient with esophageal achalasia who was treated with balloon dilatation and laparoscopic esophagomyotomy.Ahalazija je relativno rijedak poremećaj probavnog sustava kod kojega je odsutna normalna peristaltika jednjaka, te je znatno smanjeno ili odsutno opuštanje donjeg ezofagusnog sfinktera kod gutanja, što je uzrokovano degenerativnim promjenama parasimpatetične inervacije. Svi oblici liječenja su palijativni, a uključuju medikamentnu terapiju, endoskopsko ubrizgavanje toksina botulina u donji ezofagusni sfinkter, pneumatsku dilataciju balonom i kirurško liječenje. Kirurški pristup pruža najbolje dugotrajne rezultate, a može se izvesti kao otvoreni zahvat ili endoskopski zahvat koji daje odlične rezultate praćene svim dobro poznatim prednostima minimalno invazivne kirurgije. Opisan je slučaj bolesnika koji je liječen dilatacijom balonom i laparoskopskom ezofagomiotomijom

Treatment of acute myeloid leukemia using reduced intensity conditioning – method reserved for elderly patients only?

Cilj: Svrha članka bila je prezentirati dosadašnje rezultate liječenja ovom metodom u našem transplantacijskom centru, kao i proširiti svijest o potencijalnoj velikoj koristi korištenja kondicioniranja smanjenim intenzitetom u terapiji oboljelih od akutne mijeloične leukemije i mijelodisplastičnog sindroma. Metode: Od ožujka 2008. do prosinca 2010. transplantirano je ukupno 10 bolesnika, medijan dobi bio je 53,5 godina (35,3 – 58,3). Tri bolesnika prethodno su autologno, a jedan alogeno transplantirani. Svi su bolesnici dobili fludarabin-bazirano kondicioniranje, kombinaciju fludarabin, busulfan. Profilaksa GVHD-a provođena je ciklosporinom, s ili bez mikrofenolat-mofetila, te antitimocitnim globulinom u slučaju transplantacije od nesrodnog davatelja. Svi su bolesnici transplantirani perifernim hematopoetskim matičnim stanicama. Rezultati: Kumulativna incidencija akutne bolesti davatelja protiv primatelja (engl. Graft-versus-Host Disease; GVHD) bila je 30 % za gradus I – IV, odnosno 20 % za gradus III – IV; za kronični oblik bolesti 10 %. Ukupno preživljenje iznosi 20 %, a preživljenje bez znakova bolesti iznosi 22 %. Rasprava: U usporedbi s objavljivanim rezultatima, naša skupina bolesnika ima slabije ukupno preživljenje te nešto višu incidenciju GVHD-a. S obzirom na mali broj bolesnika u našoj skupini, direktna usporedba i nije moguća. Iako je ova metoda bila dizajnirana za provođenje u starije populacije bolesnika, u posljednje se vrijeme pokazala adekvatnom i u mlađih bolesnika, no za donošenje konačnog zaključka potrebno je provesti randomizirano istraživanje na većem broju bolesnika. Zaključak: U našem centru transplantirano je 10 bolesnika oboljelih od akutne mijeloične leukemije, odnosno mijelodisplastičnog sindroma, koristeći kondicioniranje smanjenog intenziteta. Iako su postignuti rezultati slabiji u usporedbi s do sada objavljivanima, prava analiza nije moguća na ovako malom broju bolesnika.Aim: The aim of this article was to present the results achieved using this method in our center, as well as to expand the knowledge of potentially great benefit that reduced conditioning is bringing in the treatment of patients with acute myeloid leukemia and myelodisplastic syndrome. Methods: From March 2008 until December 2010, a total of 10 patients were transplanted, median age was 53.5 years (range 35.3 – 58.3). Four patients were previously transplanted, three received autologous and one patient allogeneic bone marrow transplantation. All patients received conditioning consisting of fludarabine and busulphan. For Graft-versus-Host Disease (GVHD) prophylaxis they received cyclosporine, with or without Mycophenolate mofetil, and in case of unrelated donor ATG was given prior to transplantation. All of the patients received grafts consisting of peripheral hematopoietic stem cells. Results: Cumulative incidence of acute GVHD was 30 % for grade I-IV, and 20 % for grade III-IV; for chronic GVHD it was 10 %. Overall survival was 20 %; disease-free survival was 22 %. Discussion: Comparing our results with so far published series, our group has notably lower overall survival rate and somewhat higher incidence of GVHD. Considering the small number of patients in our group, direct comparison was not possible. Even though this method was designed for older group of patients, recently published data shows that this method is suitable for younger patients as well, but randomized studies on larger number of patients are still needed. Conclusion: Ten patients with acute myeloid leukemia or myelodisplastic syndrome were treated in our center using reduced intensity conditioning. Even though achieved results are not as good as those so far reported, a proper analysis is still not possible due to the small number of our patients

Inhalation plus intravenous colistin versus intravenous colistin alone for treatment of ventilator associated pneumonia

In the setting of intensive care units the incidences of multi-drug resistant gram-negative (MDR-GN) pathogens causing ventilator associated pneumonia (VAP) has increased, leading clinicians to use colistin. Our aim was to assess outcomes associated with the use of inhalation and intravenous colisitn versus only intravenous colistin in patients with MDR-GN VAP. A retrospective, single centre study at University Hospital Centre, Zagreb. Patients were divided in two groups, according to their administration of antibiotics – inhalation and intravenous (INH+IV) administration for 8 patients or intravenous only (IV) administration for 23 patients. The results showed that demographic and clinical characteristics and the gram negative pathogens isolated were similar between the two groups, except for K. pneumoniae, which was higher in the IV group. No statistically significant difference between the two groups were observed regarding intensive care unit mortality (P=0.951), sepsis (P=0.474), acute respiratory distress syndrome (P=0.548), length of ICU stay (P=0.686) and length of mechanical ventilation (P=0.858). A statistically significant difference was found regarding the eradication of pathogens in respiratory cultures (P= 0.018). The addition of inhalation to intravenous colistin in MDR-GN VAP improves microbiologic outcome, but does not improve ICU mortality in these patients. Larger prospective trials are warranted to confirm the benefit of adjunctive inhalation colistin as a MDR-GN VAP therapy in the critically ill

Chemical Characterization, Antioxidant Activity, and Cytotoxity of Wild-Growing and In Vitro Cultivated Rindera umbellata (Waldst. and Kit.) Bunge

The aim of this study was to comparatively analyze chemical composition and biological activity of wild- and in vitro grown Rindera umbellata. Explants were cultivated on 0.003–0.3 M sucrose, fructose, or glucose. HPLC-DAD for quantifying rosmarinic (RA) and lithospermic B (LAB) acids and GC-MS/FID for qualitative pyrrolizidine alkaloids (PAs) detection were used. Antioxidant activity (DPPH and ABTS assays) and cytotoxicity (MTT test) were monitored. Identified PAs were 7-angeloyl heliotridane, lindelofine, 7-angeloyl heliotridine, 7-angeloyl-9-(+)-trachelanthylheliotridine, punctanecine, and heliosupine, with higher variability reported in wild-growing samples. Total phenolic contents (TPCs) were comparable in wild-growing and in vitro samples, but total flavonoid (TFC) and RA levels were multifold higher in in vitro samples. Notably, high concentration of LAB was detected in wild-growing roots. Amounts of 0.3 M and 0.1 M of sucrose were optimal for TFC and RA production, while maximal antioxidant activity was monitored in plants grown on 0.3 M sucrose. The MTT test indicated colorectal HT-29 as more sensitive than A549 lung adenocarcinoma and normal MRC-5 cells, showing selective sensitivity to wild-growing and 0.3 M sucrose samples. In conclusion, PAs in vitro, as well as TPC, TFC, RA, and LAB in both growing conditions were detected for the first time in R. umbellata

Urogenital wounds during the war in the Croatian in 1991/1992

U radu su prikazane 142 urogenitalne ozljede u 115 od 4425 ranjenika, liječenih u Kliničkoj bolnici Osijek tijekom 18 mjeseci rata u Osijeku. Najčešće se radilo o ozljedama bubrega (64), a slučaj uretre (4) najrjeđe, s relativno velikim brojem ozljeda uretera (11). Dvije trećine ozljeda bile su povezane s ozljedama drugih, najčešće abdominalnih organa. Visoki mortalitet (15,6%) tumači se blizinom bojišnice, što je, uprkos kratkom vremenu transporta (52,21 minute), isključivalo mogućnost selekcije moribundnih slučajeva, ali i modernim eksplozivnim oružjem koje je uzrokovalo ozljede vitalnih organa. Šezdeset posto ranjenika bili su pripadnici vojske, a 40% civilne osobe. Kirurški je zahvat tendirao očuvanju organa. Tako je, na primjer, nefrektomija bila izvršena samo u četvrtini renalnih ozljeda, dok se jednu trećinu ozlijeđenih testisa uspjelo spasiti. U 5 od 8 ozljeda korpus spongiozuma penisa izvršena je slobodna transplantacija fascije late. Prilikom ozljeda uretera, resekcija, s primarnom rekonstrukcijom, dala je dobre rezultate dok je samo aplikacija proteze (bez resekcije) rezultirala stenozom.There were 142 war injuries to the urogenital organs in 115 of 4,425 wounded patients treated at our clinical hospital during 18 months of warfare in Osijek, Croatia. Kidney injury was the most common (64 cases) and urethral injury (4) the least common, with a relatively large number of ureteral injuries (11). Two-thirds of the injuries were associated with other trauma, most frequently abdominal injuries. The mortality rate was high (15.6%), explained by the proximity of the battlefield and resulting rapid patient transport (average 52.21 minutes), which excluded the posibility of separating out the moribund cases, as well as the exceptional destructive power of modern explosives and firearms and associated wounds of the vital organs. Of the wounded, 60%, were members of Croatian armed forces, 1 was member of the United Nations Protection Force and 39.13% were civilians. Surgical intervention was characterized by a tendency toward conservation and the avoidance of organ sacrifice. Thus, nephrectomy was performed in only a quarter of the cases of renal injury. Nevertheless, orchidectomy was performed in two thirds of the cases of testicular injury. In 5 of 8 cases of corpus spongiosum injury the tunica albuginea was primarily reconstructed with free transplantation of the fascia lata. For ureteral injury resection with primary suture yielded good results in contrast to stents without resection cases of ureteral wall contusion, which resulted in ureteral stenosis in our patients

Urogenital wounds during the war in the Croatian in 1991/1992

U radu su prikazane 142 urogenitalne ozljede u 115 od 4425 ranjenika, liječenih u Kliničkoj bolnici Osijek tijekom 18 mjeseci rata u Osijeku. Najčešće se radilo o ozljedama bubrega (64), a slučaj uretre (4) najrjeđe, s relativno velikim brojem ozljeda uretera (11). Dvije trećine ozljeda bile su povezane s ozljedama drugih, najčešće abdominalnih organa. Visoki mortalitet (15,6%) tumači se blizinom bojišnice, što je, uprkos kratkom vremenu transporta (52,21 minute), isključivalo mogućnost selekcije moribundnih slučajeva, ali i modernim eksplozivnim oružjem koje je uzrokovalo ozljede vitalnih organa. Šezdeset posto ranjenika bili su pripadnici vojske, a 40% civilne osobe. Kirurški je zahvat tendirao očuvanju organa. Tako je, na primjer, nefrektomija bila izvršena samo u četvrtini renalnih ozljeda, dok se jednu trećinu ozlijeđenih testisa uspjelo spasiti. U 5 od 8 ozljeda korpus spongiozuma penisa izvršena je slobodna transplantacija fascije late. Prilikom ozljeda uretera, resekcija, s primarnom rekonstrukcijom, dala je dobre rezultate dok je samo aplikacija proteze (bez resekcije) rezultirala stenozom.There were 142 war injuries to the urogenital organs in 115 of 4,425 wounded patients treated at our clinical hospital during 18 months of warfare in Osijek, Croatia. Kidney injury was the most common (64 cases) and urethral injury (4) the least common, with a relatively large number of ureteral injuries (11). Two-thirds of the injuries were associated with other trauma, most frequently abdominal injuries. The mortality rate was high (15.6%), explained by the proximity of the battlefield and resulting rapid patient transport (average 52.21 minutes), which excluded the posibility of separating out the moribund cases, as well as the exceptional destructive power of modern explosives and firearms and associated wounds of the vital organs. Of the wounded, 60%, were members of Croatian armed forces, 1 was member of the United Nations Protection Force and 39.13% were civilians. Surgical intervention was characterized by a tendency toward conservation and the avoidance of organ sacrifice. Thus, nephrectomy was performed in only a quarter of the cases of renal injury. Nevertheless, orchidectomy was performed in two thirds of the cases of testicular injury. In 5 of 8 cases of corpus spongiosum injury the tunica albuginea was primarily reconstructed with free transplantation of the fascia lata. For ureteral injury resection with primary suture yielded good results in contrast to stents without resection cases of ureteral wall contusion, which resulted in ureteral stenosis in our patients