Impressive abrasion rates of marked pebbles on a coarse-clastic beach within a 13-month timespan

In this paper the abrasion rate on a coarse-clastic beach was evaluated by calculating the volume loss recorded on indigenous pebbles within a 13-month timespan. The experiment was carried out at Marina di Pisa (Italy) on an artificial beach that was built to counteract the erosion processes affecting this sector of the coast. A total of 240 marble pebbles (120 rounded and 120 angular) were marked using the RFID technology and injected on the beach. The volume loss measured after consecutive recovery campaigns was progressively increasing, reaching the maximum value after 13 months (61% overall). The average volume loss is consistent between rounded and angular pebbles at any time (59.3% and 64.2% after 13 months respectively), meaning that the roundness is not a primary control factor on abrasion rate. The pebbles that did not reach such abrasion rates after 8 and 10 months (volume loss less than 20%) were found at heights equal or greater than 2 m above mean sea level, on the crest of the storm berm that formed during the strongest storms. This implies that the highest wearing is achieved in the lower portion of the backshore, which is also the area that underwent major topographic modifications. Here, sea water action might also exert chemical influence on the pebbles, adding to the mechanical abrasion. The main result of this research, indicating an impressive volume loss on beach pebbles in a short timespan, could be of key importance for coastal managers. The optimization of coarse sediment beach nourishments is also relevant, taking into right consideration that the volume loss due to sediment abrasion might exceed 50% of the original fill volume just after 1 year in the most dynamic portion of the beach

Foszforheterociklusok szintézise és hasznosítása = The synthesis and use of phosporus heterocycles

A kutatás három fő szálon futott, egyrészt az 5- és 6-tagú, másrészt a 7- és 8-tagú - ez utóbbi esetben áthidalt - P-heterociklusok területén, harmadrészt egy inverz Wittig-típusú reakció témájában. Újfajta foszfol- és a 3-as helyzetben foszforfunkciót tartalmazó 1,2,3,6-tetra- és 1,2,3,4,5,6-hexahidrofoszfinin P-ligandokat (ill. ez utóbbiak prekurzorait) tettük hozzáférhetővé, amelyeket átmeneti fémkomplexekké is átalakítottunk. A P-ligandok és a komplexek térszerkezetét felderítettük és ez utóbbiak egy részét katalizátorként is kipróbáltuk. Jónéhány dibenzooxafoszforint - közöttük optikai aktivitással rendelkező származékokat is - előállítottunk. A ligandok platina-komplexeit is elkészítettük. A kutatás másik vonalán új 7-foszfanorbornén, ill. 2-foszfabiciklo[2.2.2]oktén 2-oxid származékokat vezettünk be, egyrészt új szubsztituensek, másrészt új dienofilek alkalmazásával. A prekurzorokat reakcióképes intermedierek képzésén át foszforilezési reakciókban hasznosítottuk. Tanulmányoztuk a reakciók mechanizmusát és oxafoszfabiciklookténeket is vizsgáltunk. A harmadik témában a P-aril gyűrűs foszfin-oxidok és a dialkilacetiléndikarboxilát béta-oxofoszforánokat eredményező reakcióinak mechanizmusát derítettük fel és megfontoltuk az oxafoszfetének mint intermedierek lehetőségét. A béta-oxofoszforánokat kerülő szintézissel is hozzáférhetővé tettük és tanulmányoztuk néhány jellemző reakciójukat. | The research was performed in three topics, on one hand in the topic of 5- and 6-membered P-heterocycles, on the other hand in the field of 7- and 8-membered P-cycles including bridged derivatives, and finally in the topic of the inverse Wittig type reaction. New phosphole and 1,2,3,6-tetra- and 1,2,3,4,5,6-hexahydrophosphinine P-ligands - these latter with exocyclic P-function in position three - were made available that were also transformed to transition metal complexes. Stereostructure of the P-ligands and complexes was evaluated and a part of the latter was tested as catalyst. A number of dibenzooxaphosphorines and their platinum complexes were also prepared. In the second line of the research, new 7-phosphanorbornene- and 2-phosphabicyclo[2.2.2]octene 2-oxide derivatives were introduced and utilized in fragmentation related phosphorylation of nucleophiles. Beside the mechanistic studies, oxaphosphabicyclooctenes were also studied. In the third topic, the mechanism of the inverse Wittig type reaction of cyclic phosphine oxides and dialkyl acetylenedicarboxylate resulting in beta-oxophosphoranes was studied. Oxaphosphetes were considered as possible intermediates. The beta-oxophosphoranes were also prepared by an independent synthesis and some of their reactions were investigated

Miyazaki Syndrome due to Ventriculoperitoneal Shunt Treatment

The signs and pathomechanism of Miyazaki syndrome is presented through the case of a young female patient. The patient underwent placement of a ventriculoperitoneal (VP) shunt with a pressure-adjustable valve for communicating hydrocephalus years before presenting to our department with the complaints of constant headache and unsteady gait. On the basis of the clinical picture and her history, plain and contrast-enhanced cranial and whole spine magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) examinations were performed, with the scans revealing signs indicative of cerebrospinal fluid (CSF) hypotension typical of Miyazaki syndrome. The paper discusses the available literature suggesting the underlying cause in such cases to be the dysfunction of the Starling resistor mechanism due to an improperly adjusted VP shunt, which results in excessive CSF loss accompanied by consequent cerebral venous overflow with vertebral venous engorgement and compressive cervical myelopathy

The involvement of histaminic and muscarinic receptors in the bronchoconstriction induced by myorelaxant administration in sensitized rabbits

BACKGROUND: Muscle relaxants cause bronchospasm via histamine release and/or by acting on the muscarinic receptors; we sought to characterize the respective importance of these pathways in the presence of bronchial hyperreactivity. METHODS: Ovalbumin-sensitized rabbits were randomly assigned to several protocol groups: Group C comprised untreated animals; in the other three groups, either H1 and H2 histaminic receptor blockade was performed, leaving the M1, M2, and M3 muscarinic receptors functional (Group M123), or combining this treatment with M3 muscarinic receptor blockade (Group M12), or with vagotomy (Group M3). Respiratory system impedance was measured over a 90-s period, during which succinylcholine, mivacurium or atracurium was administered. To monitor the changes in lung mechanics, respiratory system impedance was averaged in a 2-s time window and fitted by a model featuring airway resistance and inertance and tissue damping and elastance. RESULTS: The peak increases in airway resistance in Group C were greatest with succinylcholine (79 +/- 17[SE]%) and mivacurium administration (75% +/- 12%), whereas they were lower after attracurium (40% +/- 11%). These changes were markedly attenuated by both histamine and muscarinic receptor blockade with the largest reduction in Group M3 for succinylcholine (14% +/- 5.2%), and in Group M123 for mivacurium (5.1% +/- 9.1%) and attracurium (7.8% +/- 4.0%). DISCUSSION: Although the bronchospasm developing in the allergic airways after muscle relaxants is mediated primarily by the histaminic pathway, the interactions of succinylcholine on the M1, M2, and M3 receptors, those of atracurium on the M1 and M2 receptors, and those of mivacurium on the M3 receptors may also play a role

Burnout and Occupational Stress Among Hungarian Radiographers Working in Emergency and Non-Emergency Departments During COVID-19 Pandemic

Introduction: The increased workload caused by the coronavirus pandemic may have had a significant impact on the mental health of radiographers. The aim of our study was to investigate burnout and occupational stress in radiographers working in emergency departments (ED) and non-emergency departments (NED). Methods: Quantitative, cross-sectional, descriptive research was carried out among radiographers working in the public health sector in Hungary. Due to the cross-sectional nature of our survey, there was no overlap between the ED and NED groups. For data collection, we used simultaneously the Maslach Burnout Inventory (MBI), the Effort-Reward Imbalance questionnaire (ERI), and our self-designed questionnaire. Results: We excluded incomplete questionnaires from our survey; finally, 439 responses were evaluated. Significantly higher scores for depersonalisation (DP; 8.43 (SD = 6.69) vs. 5.63 (SD = 4.21) and emotional exhaustion (EE; 25.07 (SD = 11.41) vs. 19.72 (SD = 11.72)) were observed in radiographers working in ED (p = 0.001; p = 0.001) when compared to NED. Male radiographers working in ED aged 20–29 and 30–39 years with experience of 1–9 years were more affected by DP (p ≤ 0.05). Worrying about one's own health had a negative effect on DP and EE (p ≤ 0.05). Having close friend with a COVID-19 infection had a negative effect on EE (p ≤ 0.05); not being infected with coronavirus, not being quarantined and relocating within the workplace had a positive effect on personal accomplishment (PA); radiographers who were 50 years or older with 20–29 years of experience were more affected by depersonalisation (DP); and those who worried about their health had significantly higher stress scores (p ≤ 0.05) in both ED and NED settings. Conclusion: Male radiographers at the beginning of their careers were more affected by burnout. Employment in EDs had a negative impact on DP and EE. Implications for practice: Our results support the implementation of interventions to counter the effects of occupational stress and burnout among radiographers working in ED