The impact of mechanical shear on membrane flux and energy demand

The use of forced mechanical shear for both disc membranes (rotating and vibrating disc filtration, RDF and VDF respectively) and hollow fibres (vibrating HF membranes, VHFM) is reviewed. These systems have been extensively studied and, in the case of the disc membranes, have reached commercialisation and proven effective in achieving transmembrane pressure (TMP) control for various challenging feed waters. The effects of operating conditions, namely shear rate as enhanced by rotation and vibration speed and TMP, and feed water quality on the filtration flux and specific energy consumption are quantified as part of the review. A new relationship is revealed between the two empirical constants governing the classical relationship between membrane flux and shear rate, and a mathematical correlation proposed accordingly. A study of available information on energy reveals that operation at lower shear rates (i.e. rotation or vibration speeds) and more conservative fluxes leads to lower specific energy demands in kWh m−3 permeate, albeit with a larger required membrane area

Cleaning of ceramic membranes for produced water filtration

The application of ceramic microfiltration membranes to the tertiary treatment of produced water from an Arabian Gulf oilfield has been studied using a dedicated pilot plant. Studies were based on a previously published protocol in which the retentate stream was recycled so as to successively increase the feed concentration throughout the experimental run. Chemical cleaning in place (CIP) was applied between each run and the flux and permeability recovery recorded for various cleaning protocols studied, the CIP being based on the combination of caustic soda (NaOH) and citric acid. Surface analysis of the membrane, and specifically its hydrophilicity, was also conducted. Results indicated the main influencing factor on permeability recovery from the CIP to be the employment of backflushing during the CIP itself. A final flux of 700 L m−2 h−1 was sustained through the application of 6 wt% NaOH with 6 wt% citric acid combined with backflushing at approximately twice the rate of the filtration cycle flux. A consideration of the impact of this flux value on the viability of two commercially-available ceramic membrane technologies indicated the footprint incurred to be slightly lower than that of the upstream induced gas flotation technology and corroborated a previously published estimate. The flux was sustained despite surface analysis indicating a loss of the innate hydrophilicity of the ceramic membrane

Pregnancy outcomes of women with untreated ‘mild’ gestational diabetes (gestational diabetes by the WHO 2013 but not by the WHO-1999 diagnostic criteria) – A population-based cohort study

AIMS: We compared pregnancy outcomes of untreated 'mild' GDM (GDM by WHO 2013 but not by WHO-1999) to normal glucose tolerant women (NGT). METHODS: In a universal screening program 4333 pregnant women had a 3-point 75 g OGTT in Hungary in 2009-2013. By WHO-2013 untreated NGT was diagnosed in n = 3303, 'mild' GDM in n = 336 cases. RESULTS: 'Mild' GDM women were older (mean difference, SE: 1.4, 0.3 yrs), had higher fasting (1.0, 0.02), 60-minute (1.0, 0.09), and 120-minute (0.4, 0.06 mmol/l) blood glucose, and blood pressure (2.6, 0.5/2.0, 0.5 mmHg). Weight gain was similar in both groups (-0.3, 0.3 kg). GDM newborns were heavier (142, 50 g) and were more frequently macrosomic (>4000 g, OR 1.85, 95 %CI 1.35-2.54). Hypertension during pregnancy was more prevalent in the GDM group (OR 1.55, 95 %CI 1.05-2.28), as well as induced (OR 1.38, 95 %CI 1.10-1.74) and instrumental delivery (OR 1.34, 95 %CI 1.07-1.68), and acute caesarean section (OR 1.32, 95 %CI 1.04-1.64). Most of these differences substantially attenuated or became non-significant after adjustment for pre-pregnancy BMI. CONCLUSIONS: Pregnancy outcomes of 'mild' GDM were worse compared to normal glucose tolerant women however these differences were explained by the pre-pregnancy BMI difference between groups

A születési súlyok megoszlása 2011 és 2015 között és a percentilisértékek változása 1996 és 2015 között. A Tauffer-adatbázis feldolgozása = A születési súlyok megoszlása 2011 és 2015 között és a percentilisértékek változása 1996 és 2015 között. A Tauffer-adatbázis feldolgozása

Absztrakt: Bevezetés és célkitűzés: Kutatási célunk a 2011 és 2015 közötti magyarországi szülések feldolgozásának segítségével gesztációs hetekre, nemekre, valamint egyes és többes terhességből született magzatokra bontott aktuális percentilistáblázat megalkotása. Emellett vizsgáltuk, hogy 1996 és 2015 között ötéves periódusokban hogyan változtak gesztációs hetenként az egyes és iker fiú- és leánymagzatok átlag születési súlyai. Módszer: A Magyarországon kötelezően kitöltendő és vezetett Tauffer-statisztika 2011 és 2015 közötti adatai alapján minden gesztációs héthez kiszámoltuk az 5, 10, 25, 50, 75, 90 és 95 percentilisértéket nemenként, egyes és ikerterhességek esetén. Vizsgáltuk továbbá a születési súlyok terhességi hetenkénti változását 1996 és 2015 között ötéves periódusokban. Eredmények: A 2011 és 2015 közötti élveszületések súly-percentilisértékeit grafikusan ábrázoltuk, és táblázatokban is összefoglaltuk. A vizsgált 20 év alatt az egyes terhességekben a 35–41. héten a születési súly 2011–2015-höz viszonyítva az 1996–2005-ig terjedő időszakban alacsonyabb volt (a legalacsonyabb 1996–2000-ben), míg a 2006–2010-es periódusban magasabb vagy hasonló volt (például a 38. héten a fiúknál 2011–2015-ben az átlagsúly 3249 g, 1996–2000-ben 34,3 [SE 3,0] g-mal, 2001–2005-ben 11,5 [2,9] g-mal kevesebb, 2006–2010-ben 18,1 [2,9] g-mal több). Az ikerterhességekben hasonló, de nem egyértelmű tendenciát figyeltünk meg a 35–38. heti születési súlyokban. Következtetés: Tekintettel a születési súlyok elmúlt 20 évben megfigyelt jelentős változására, szükséges az általában használt percentilistáblázat megújítása. A születési súlyok 1996 és 2010 között növekedtek, elsősorban az érett magzatok esetén, az ezt követő periódusban csökkenő vagy stagnáló tendencia figyelhető meg. Orv Hetil. 2019; 160(36): 1426–1436. | Abstract: Introduction and aim: We aimed to provide a current birth weight percentile table for singleton and twin pregnancies stratified by gestational week at delivery and sex using data from all live births in Hungary between 2011 and 2015. In addition, we examined temporal trends in average birth weights in singleton and twin pregnancies by sex in five-year periods between 1996 and 2015. Method: We calculated the 5th, 10th, 25th, 50th, 75th, 90th, and 95th centiles of birth weight for each gestational week by sex for singleton and twin pregnancies using compulsory collected obstetrical data (Tauffer Statistics) in Hungary in 2011–2015. Furthermore, we described changes in birth weights by gestational week between 5-year periods from 1996 to 2015. Results: We present birth weight centiles for live births in both tabular and graphical forms using data from 2011 to 2015. In general, live birth weights in gestational weeks 35–41 were lower in the period of 1996–2005 (the lowest in 1996–2000) and were higher in the period of 2006–2010 compared to the reference period of 2011–2015 (e.g., the average male newborn weighed 3249 g at gestational week 38 in 2011–2015, which is 34.3 [SE at 3.0] g less in 1996–2000, 11.5 [2.9] g less in 2001–2005, and 18.1 [2.9] g more in 2006–2010). Similar trends were not observed in birth weights of twin pregnancies in gestational weeks 35–38. Conclusion: Given the observed substantial change in birth weights during the past 20 years, renewal of the commonly used percentile tables is necessary. Birth weights increased from 1996 to 2010, mainly of mature newborns, followed by a stabilization or slight decrease in the later periods. Orv Hetil. 2019; 160(36): 1426–1436

Trend of pregnancy outcomes in type 1 diabetes compared to control women: a register-based analysis in 1996-2018

INTRODUCTION: In 1989, the St Vincent declaration aimed to approximate pregnancy outcomes of diabetes to that of healthy pregnancies. We aimed to compare frequency and trends of outcomes of pregnancies affected by type 1 diabetes and controls in 1996-2018. METHODS: We used anonymized records of a mandatory nation-wide registry of all deliveries between gestational weeks 24 and 42 in Hungary. We included all singleton births (4,091 type 1 diabetes, 1,879,183 controls) between 1996 and 2018. We compared frequency and trends of pregnancy outcomes between type 1 diabetes and control pregnancies using hierarchical Poisson regression. RESULTS: The frequency of stillbirth, perinatal mortality, large for gestational age, caesarean section, admission to neonatal intensive care unit (NICU), and low Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) score was 2-4 times higher in type 1 diabetes compared to controls, while the risk of congenital malformations was increased by 51% and SGA was decreased by 42% (all p<0.05). These observations remained significant after adjustment for confounders except for low APGAR scores. We found decreasing rate ratios comparing cases and controls over time for caesarean sections, low APGAR scores (p<0.05), and for NICU admissions (p=0.052) in adjusted models. The difference between cases and controls became non-significant after 2009. No linear trends were observed for the other outcomes. CONCLUSIONS: Although we found that the rates of SGA, NICU care, and low APGAR score improved in pregnancies complicated by type 1 diabetes, the target of the St Vincent Declaration was only achieved for the occurrence of low APGAR scores

Breech presentation at term and associated obstetric risks factors-a nationwide population based cohort study

Purpose The aim of this study was to estimate whether breech presentation at term was associated with known individual obstetric risk factors for adverse fetal outcome. Methods This was a retrospective, nationwide Finnish population-based cohort study. Obstetric risks in all breech and vertex singleton deliveries at term were compared between the years 2005 and 2014. A multivariable logistic regression model was used to determine significant risk factors. Results The breech presentation rate at term for singleton pregnancies was 2.4%. The stillbirth rate in term breech presentation was significantly higher compared to cephalic presentation (0.2 vs 0.1%). The odds ratios (95% CIs) for fetal growth restriction, oligohydramnios, gestational diabetes, a history of cesarean section and congenital fetal abnormalities were 1.19 CI (1.07-1.32), 1.42 CI (1.27-1.57), 1.06 CI (1.00-1.13), 2.13 (1.98-2.29) and 2.01 CI (1.92-2.11). Conclusions The study showed that breech presentation at term on its own was significantly associated with antenatal stillbirth and a number of individual obstetric risk factors for adverse perinatal outcomes. The risk factors included oligohydramnios, fetal growth restriction, gestational diabetes, history of caesarean section and congenital anomalies.Peer reviewe

Biological treatment and thickening with a hollow fibre membrane bioreactor

Aerobic operation of an immersed hollow fibre membrane bioreactor, treating municipal wastewater supplemented with molasses solution, has been studied across mixed liquor suspended solids (MLSS) concentrations between 8 and 32 g L-1, the higher concentrations being normally associated with thickening operations. Only a marginal loss in membrane permeability was noted between 8 and 18 g L-1 when operation was conducted without clogging. The sustainable operational flux attainable above 18 g L-1 was highly dependent upon both the MLSS concentration and the state of the membrane. A temperature-corrected flux of 28 L m-2 h-1 (LMH) was sustained for 18 h at an MLSS of 8 g L-1 using membranes close to initial their virgin-state permeability. This value decreased to around 14 LMH at 20 g L-1 and 5 LMH at 32 g L-1 MLSS for an aged membrane whose permeability had been recovered following clogging. Below the threshold flux operation without significant clogging was possible, such that the membrane permeability could be recovered with a chemically enhanced backflush (CEB). Above this flux clogging took place at a rate of around 7-14 g solids per m2 membrane per m3 permeate volume passed irrespective of the MLSS concentration. The permeability of the unclogged membrane was depressed and could not be recovered using a standard CEB, indicative of irrecoverable pore clogging. The outcomes corroborated previously reported observations concerning the deleterious long-term impacts of clogging, and confirmed the critical importance of operation at a sustainable flux valu

Transformation of a ferry ship into a ship hospital for COVID-19 patients

Liguria is a northwestern region of Italy that, since the WHO has declared COVID-19 as a pandemic (11 March 2020), presented 108 patients hospitalized, 34 of which were in the intensive care unit. Due to this serious epidemiological emergency, the transformation of a long-distance ferry ship into a hospital ship for COVID-19 patients who were still positive after the acute phase of the illness was carried out to free up hospital beds for patients in the acute phase. The ship was moored in the port of Genoa, the capital of Liguria. The conversion was localized to a single deck, where designated healthcare areas were identified. From 23 March to 18 June 2020, 191 patients were admitted onto the ship; they were provided with high-level healthcare guaranteed by the multi-disciplinary nature of clinical competencies available. Patients had a favorable outcome in all cases, confirmed by their recovery and negative swab results. Moreover, no cases of voluntary discharge were recorded. To the best of our knowledge, this is the only example in the world in which a passenger ship was transformed into a ship hospital for COVID patients