Unexpected Periodicity in Cationic Group 5 Initiators for the Ring-Opening Polymerization of Lactones.

ε-Caprolactone (ε-CL) adducts of cationic, amine tris(phenolate)-supported niobium(V) and tantalum(V) ethoxides initiate the ring-opening polymerization of lactones. The Ta(V) species prepared and applied catalytically herein exhibits higher activity in the ring-opening polymerization (ROP) of ε-caprolactone than the previously reported, isostructural Nb(V) complex, contradicting literature comparisons of Nb(V)- and Ta(V)-based protocols. Both systems also initiate the ROP of δ-valerolactone and rac-ß-butyrolactone, kinetic studies confirming retention of higher activity by the Ta congener. Polymerizations of rac-ß-butyrolactone and δ-valerolactone were previously unrealized under Group V- or Ta-mediated conditions, respectively, although the former has afforded only low molecular weight, cyclic poly-3-hydroxybutyrate. Cationic ethoxo-Nb(V) and -Ta(V) δ-valerolactone adducts are also reported, demonstrating the facility of δ-valerolactone as a ligand and the generality of the synthetic method. Both δ-valerolactone-bearing complexes initiate the ROP of ε-caprolactone, δ-valerolactone, and rac-ß-butyrolactone. Accordingly, we have elucidated trends in reactivity and investigated the initiation mechanism for such systems, the insertion event being predicated upon intramolecular nucleophilic attack on the coordinated lactone by the adjacent alkoxide moiety. This mechanism enables quantitative, stoichiometric installation of a single monomer residue distinct from the bulk of the polymer chain, and permits modification of polymer properties via both manipulation of the molecular architecture and tuning of the polymerization kinetics, and thus dispersity, through hitherto inaccessible independent control of the initiation event.

Coordination of ε-Caprolactone to a Cationic Niobium(V) Alkoxide Complex: Fundamental Insight into Ring-Opening Polymerization via Coordination-Insertion.

We report three niobium-based initiators for the catalytic ring-opening polymerization (ROP) of ε-caprolactone, exhibiting good activity and molecular weight control. In particular, we have prepared on the gram-scale and fully characterized a monometallic cationic alkoxo-Nb(V) ε-caprolactone adduct representing, to the best of our knowledge, an unprecedented example of a metal complex with an intact lactone monomer and a functional ROP-initiating group simultaneously coordinated at the metal center. At 80 °C, all three systems initiate the immortal solution-state ROP of ε-caprolactone via a coordination-insertion mechanism, which has been confirmed through experimental studies, and is supported by computational data. Natural bond orbital calculations further indicate that polymerization may necessitate isomerization about the metal center between the alkoxide chain and the coordinated monomer. The observations made in this work are expected to inform mechanistic understanding both of amine tris(phenolate)-supported metal alkoxide ROP initiators, including various highly stereoselective systems for the polymerization of lactides and of coordination-insertion-type ROP protocols more broadly.

Investigation of an international outbreak of multidrug-resistant monophasic Salmonella Typhimurium associated with chocolate products, EU/EEA and United Kingdom, February to April 2022.

An extensive multi-country outbreak of multidrug-resistant monophasic Salmonella Typhimurium infection in 10 countries with 150 reported cases, predominantly affecting young children, has been linked to chocolate products produced by a large multinational company. Extensive withdrawals and recalls of multiple product lines have been undertaken. With Easter approaching, widespread product distribution and the vulnerability of the affected population, early and effective real-time sharing of microbiological and epidemiological information has been of critical importance in effectively managing this serious food-borne incident.

Spatiotemporal Dynamics of Sporadic Shiga Toxin-Producing Escherichia coli Enteritis, Ireland, 2013-2017.

The Republic of Ireland regularly reports the highest annual crude incidence rates of Shiga toxin-producing Escherichia coli (STEC) enteritis in the European Union, ≈10 times the average. We investigated spatiotemporal patterns of STEC enteritis in Ireland using multiple statistical tools. Overall, we georeferenced 2,755 cases of infection during January 2013-December 2017; we found >1 case notified in 2,340 (12.6%) of 18,641 Census Small Areas. We encountered the highest case numbers in children 0-5 years of age (n = 1,101, 39.6%) and associated with serogroups O26 (n = 800, 29%) and O157 (n = 638, 23.2%). Overall, we identified 17 space-time clusters, ranging from 2 (2014) to 5 (2017) clusters of sporadic infection per year; we detected recurrent clustering in 3 distinct geographic regions in the west and mid-west, all of which are primarily rural. Our findings can be used to enable targeted epidemiologic intervention and surveillance.

Geocoding cryptosporidiosis cases in Ireland (2008-2017)-development of a reliable, reproducible, multiphase geocoding methodology.

BACKGROUND: Geocoding (the process of converting a text address into spatial data) quality may affect geospatial epidemiological study findings. No national standards for best geocoding practice exist in Ireland. Irish postcodes (Eircodes) are not routinely recorded for infectious disease notifications and > 35% of dwellings have non-unique addresses. This may result in incomplete geocoding and introduce systematic errors into studies. AIMS: This study aimed to develop a reliable and reproducible methodology to geocode cryptosporidiosis notifications to fine-resolution spatial units (Census 2016 Small Areas), to enhance data validity and completeness, thus improving geospatial epidemiological studies. METHODS: A protocol was devised to utilise geocoding tools developed by the Health Service Executive's Health Intelligence Unit. Geocoding employed finite-string automated and manual matching, undertaken sequentially in three additive phases. The protocol was applied to a cryptosporidiosis notification dataset (2008-2017) from Ireland's Computerised Infectious Disease Reporting System. Outputs were validated against devised criteria. RESULTS: Overall, 92.1% (4266/4633) of cases were successfully geocoded to one Small Area, and 95.5% (n = 4425) to larger spatial units. The proportion of records geocoded increased by 14% using the multiphase approach, with 5% of records re-assigned to a different spatial unit. CONCLUSIONS: The developed multiphase protocol improved the completeness and validity of geocoding, thus increasing the power of subsequent studies. The authors recommend capturing Eircodes ideally using application programming interface for infectious disease or other health-related datasets, for more efficient and reliable geocoding. Where Eircodes are not recorded/available, for best geocoding practice, we recommend this (or a similar) quality driven protocol.

A 'Life-Style Choice' or a Philosophical Belief?: The Argument for Veganism and Vegetarianism to be a Protected Philosophical Belief and the Position in England and Wales.

The recent judgment in Casamitjana Costa v The League Against Cruel Sports in England and Wales held that ethical veganism was a protected philosophical belief under employment law. In contrast, vegetarianism was found not to be a protected philosophical belief in Conisbee v Crossley Farms Limited and others. The authors argue that the Employment Tribunal misunderstood the notion of vegetarianism when deciding that it was a 'life-style choice'. There are different kinds of vegans and vegetarians, each with their own way of practising the philosophy which influences how they live their life. Not all people who follow a meat-free diet should be afforded this protection, and it depends on whether their belief is one which is determined by certain factors, such as animal welfare and environmentalism, rather than for health purposes. The authors explore the arguments and analysis in the above employment cases, coming to the conclusion that the tribunals oversimplified what it means to hold values such as veganism and vegetarianism, failing to understand the differences between different classifications and sub-groups when coming to a decision. The different kinds of vegans and vegetarians and their characteristics are outlined, before determining whether this should constitute protection under employment law, protecting individuals from discrimination. The situation in the USA and Canada regarding this issue is very different, and there are parallels drawn with attempting to establish veganism or vegetarianism as a religion, and where they could benefit from the recent decision in England and Wales. Finally, this paper concludes that ethical and environmental veganism and vegetarianism should both qualify as protected philosophical beliefs, but other kinds may fall short of what is required to satisfy the requirements under law.

Chemical Degradation of End-of-Life Poly(lactic acid) into Methyl Lactate by a Zn(II) Complex.

The catalyzed methanolysis of end-of-life poly(lactic acid) (PLA) products by an ethylenediamine Zn(II) complex to form biodegradable methyl lactate was studied experimentally at 70, 90, and 110 °C. The PLA samples consisted of typical consumer waste materials, including a cup, a toy, and a three-dimensional (3D) printing material. High selectivities and yields (>94%) were possible depending on temperature and reaction time. Additionally, and to develop a predictive kinetic model, kinetic parameters (pre-exponential factor and activation energies) of the PLA transesterification reaction were first obtained from virgin PLA. These parameters were subsequently used to estimate the conversion of PLA, selectivity, and yield of methyl lactate after 1 and 4 h of the reaction, and the results were compared with the experimental values of the end-of-life PLA. Despite the presence of unknown additives in the PLA waste material and uncontrolled particle size, the model was able to predict the overall conversion, selectivity, and yield to an average deviation of 5, 7, and 12%, respectively. A greater agreement between the model and experimental values is observed for the higher temperatures and the longer reaction time. Larger deviations were observed for the PLA toy, which we attribute to the presence of additives, since despite its lower molecular weight, it possessed a higher structural strength.

Novel hybrid aluminium(iii)-catalen complexes as highly active catalysts for lactide polymerisation: towards industrial relevance.

Herein, we report a series of highly active Al(iii)-complexes based on a novel hybrid ligand: the catalen. Their application in the production of polylactide under both solution, and industrially preferred melt conditions, is demonstrated. Potential structural diversification to broaden initiator scope is discussed.

Kinetics of Methyl Lactate Formation from the Transesterification of Polylactic Acid Catalyzed by Zn(II) Complexes.

The kinetics of the transesterification of polylactic acid (PLA) with methanol to form methyl lactate catalyzed by Zn(II) complexes was studied experimentally and numerically. The complexes, Zn(1 Et )2 and Zn(2 Pr )2, were synthesized from ethylenediamine and propylenediamine Schiff bases, respectively. The temperature range covered was 313.2-383.2 K. An increase in the reaction rate with the increase in temperature was observed for the Zn(1 Et )2-catalyzed reaction. The temperature relationship of the rate coefficients can be explained by a linear Arrhenius dependency with constant activation energy. The kinetics of Zn(2 Pr )2, on the other hand, is only explained by non-Arrhenius kinetics with convex variable activation energy, resulting in faster methyl lactate production rates at 323.2 and 343.2 K. The formation of a new catalyst species, likely through reaction with protic reagents, appears to promote the formation of intermediate complexes, resulting in the nonlinear behavior. Stirring speed induced the stability of the intermediate complexes. Contrary to Zn(1 Et )2, Zn(2 Pr )2 was susceptible to the presence of air/moisture in solution. The kinetic parameters were obtained by fitting the experimental data to the mass and energy balance of a consecutive second step reversible reaction taking place in a jacketed stirred batch reactor. For the case of Zn(2 Pr )2, the activation energy was fitted to a four-parameter equation. The kinetic parameters presented in this work are valuable for the design of processes involving the chemical recycling of PLA into green solvents.

Epidemiology of Campylobacter infections in Ireland 2004-2016: What has changed?

Campylobacter is the most common notifiable cause of bacterial gastroenteritis in humans in Ireland. However, epidemiological information is limited. We aimed to describe Campylobacter epidemiology in Ireland and trends over time, to inform future surveillance and research. We reviewed data completeness and described notified cases of campylobacteriosis (2004-2016) by age, sex, geographical area, season and trends over time. We used negative binomial regression to estimate incidence rate ratios (IRR) and adjusted IRR (aIRR) by age group, sex, geographical area and season. We undertook interrupted time-series analysis by age group and geographical area incorporating terms for trend and period (2004-2010 and 2011-2016). There were 27,034 cases of campylobacteriosis notified between 2004 and 2016. Data were >99% complete for notification date, geographical area, sex and date of birth. Crude annual incidence ranged from 36.2 to 54.4 per 100,000 population. The incidence was higher in, males (aIRR 1.15, 95% confidence intervals (CI) 1.12-1.19), those aged <5 years compared with the lowest incidence age group (45-64 years) (aIRR 4.65, 95% CI 4.43-4.88), other seasons compared with winter and all other areas compared with the north-east area (aIRR range 1.22-1.71, p-values <.001). In 2011, we observed a stepped increase in annual crude incidence overall, in both sexes, all age groups and most geographical areas. This pattern was mirrored on time-series analysis, with significant increases in trend-adjusted incidences of 30%-45% (p-values ≤.008) detected for all age groups and 30%-66% (p-values ≤.012) for seven out of eight geographical areas after 2011. Campylobacter remains the most commonly notified bacterial cause of gastroenteritis in Ireland. With available information, we could not fully explain a stepped increase in incidence observed in 2011. The transition of regional laboratories from culture-based to molecular-based Campylobacter diagnostic methods was a possible contributor. However, further investigation is required to fully explain the identified changes.

Zinc Complexes for PLA Formation and Chemical Recycling: Towards a Circular Economy.

A series of ZnII complexes, based on propylenediamine Schiff bases, have been prepared and fully characterized. X-ray crystallography and NMR spectroscopy identified significant differences in the solid and solution state for the ZnII species. All complexes have been applied to the ring-opening polymerization of l-lactide with emphasis on industrial conditions. High conversion and good molecular weight control were generally achievable for Zn(A-D)2 , and high-molecular-weight poly(lactic acid) (PLA) was prepared in 1 min at a 10 000:1:33 [lactide]/[Zn]/[BnOH] loading. The more active ZnII catalysts were also applied to PLA degradation to alkyl lactate under mild conditions. Zn(A-B)2 demonstrated high activity and selectivity in this process with PLA being consumed within 1 h at 50 °C. Zn(C-D)2 were shown to be less active, and these observations can be related to the catalysts' structure and the degradation mechanism. Initial results for the degradation of poly(ethylene terephthalate) and mixed feeds are also presented, highlighting the broader applicability of the systems presented.

The synthesis, characterisation and application of iron(iii)-acetate complexes for cyclic carbonate formation and the polymerisation of lactide.

Herein, we report the preparation, characterisation and catalytic applications of air-stable Fe(iii)-acetate complexes consisting of salan, salen and salalen ligand frameworks. Owing to the simple synthetic protocol employed, a wide range of complexes have been prepared and structure-activity-relationships investigated. X-ray diffraction confirmed the solid-state structures for eight of the complexes. These represent the first Fe(iii)-acetate complexes applied for the selective coupling of CO2/epoxide and lactide polymerisation. The coupling of CO2 and challenging cyclohexene oxide substrate was performed under mild, solvent-free conditions (80 °C, 10 bar CO2) to selectively form the cis-cyclohexene carbonate as the exclusive product (selectivity >99%) with a metal loading of 0.08 mol%. A reduced aminopiperidine ligand backbone was found as the most active catalyst, and after investigating four co-catalysts, showed high functional group tolerance and robustness when applied to a broad, commercially available, terminal epoxide substrate scope with high conversions observed. The ring-opening polymerisation of rac-lactide was achieved using the Fe(iii)OAc complexes using triethylamine and benzyl alcohol for initiation, interestingly isoselectivity was observed in some cases.

Tuning a robust system: N,O zinc guanidine catalysts for the ROP of lactide.

Non-toxic, highly active and robust complexes are the holy grail as ideal green catalysts for the polymerisation of biorenewable and biodegradable polylactide. Four new zinc guanidine complexes [ZnCl2(TMG4NMe2asme)], [ZnCl2(TMG5Clasme)], [ZnCl2(TMG5Measme)] and [ZnCl2(TMG5NMe2asme)] with different electron-donating and electron-withdrawing groups on the ligand's aromatic backbone have been synthesised. Ligands are derived from low-cost commercially available compounds and have been converted by a three- or four-step synthesis process into the desired ligand in good yields. The compounds have been fully characterised and tested in the ROP of rac-LA under industrially relevant conditions. The complexes are based on the recently published structure [ZnCl2(TMGasme)] which has shown high activity in the polymerisation of lactide at 150 °C. Different substituents in the para-position of the guanidine moiety significantly increase the polymerisation rate whereas positioning substituents in the meta-position causes no change in the reaction rate. With molecular weights over 71 000 g mol-1 being achievable, the best system produces polymers for multiple industrial applications and its polymerisation rate approaches that of Sn(Oct)2. The robust systems are able to polymerise non-purified lactide. The initiation of the polymerisation is suggested to occur due to impurities in the monomer.

Highly Active N,O Zinc Guanidine Catalysts for the Ring-Opening Polymerization of Lactide.

New zinc guanidine complexes with N,O donor functionalities were prepared, characterized by X-Ray crystallography, and examined for their catalytic activity in the solvent-free ring-opening polymerization (ROP) of technical-grade rac-lactide at 150 °C. All complexes showed a high activity. The fastest complex [ZnCl2 (DMEGasme)] (C1) produced colorless poly(lactide) (PLA) after 90 min with a conversion of 52 % and high molar masses (Mw =69 100, polydispersity=1.4). The complexes were tested with different monomer-to-initiator ratios to determine the rate constant kp . Furthermore, a polymerization with the most active complex C1 was monitored by in situ Raman spectroscopy. Overall, conversion of up to 90 % can be obtained. End-group analysis was performed to clarify the mechanism. All four complexes combine robustness against impurities in the lactide with high polymerization rates, and they represent the fastest robust lactide ROP catalysts to date, opening new avenues to a sustainable ROP catalyst family for industrial use.

Ligands and complexes based on piperidine and their exploitation of the ring opening polymerisation of rac-lactide.

A range of ligands based upon 2-(aminomethyl)piperidine have been successfully complexed to Mg(ii), Zn(ii) and group IV metal centres. These complexes have been characterised both in solution and solid state with different coordination geometries realised dependant on the nature of the ligand. For the Mg(ii) and Zn(ii) complexes, M(1-2)2, were isolated and analysed by DOSY NMR spectroscopy. These ligands also furnished diastereomeric group IV complexes, M(1-2)2(OiPr)2. Group IV salalen and salan complexes, M(4-5)(OR)2 were also found to be diastereomeric in nature, with either ß-cis or α-cis geometriesrespectively. The tridentate ligand, 6H2, yielded five coordinate complexes with both Ti(iv) and Zr(iv). All complexes were screened for the ring opening polymerisation of rac-lactide under both solvent and melt conditions. For the Mg(ii) and Zn(ii) complexes, good activity was observed with Zn(1-2)2 demonstrating immortal polymerisation characteristics.

Aluminium salalens vs. salans: "Initiator Design" for the isoselective polymerisation of rac-lactide.

We report the rationalised design of aluminium initiators and their application for ROP of rac-lactide (rac-LA). A very minor change to the ligand backbone (imine reduction) to give secondary amines was found to have a dramatic effect on activity and selectivity with isotactic PLA being realised.

A population based study comparing changes in rotavirus burden on the Island of Ireland between a highly vaccinated population and an unvaccinated population.

BACKGROUND: Rotavirus infection is a leading cause of gastroenteritis in infants and children globally. Reductions in rotavirus activity have been observed following introduction of rotavirus vaccination programmes, however a reductions have also been reported in some unvaccinated countries. The Island of Ireland incorporates the two jurisdictions Northern Ireland (NI) and the Republic of Ireland (IE). Both have similarities in climate, demography, morbidity and mortality but distinct health administrations and vaccination policies. Rotarix was added to the childhood immunisation programme in NI on the 1 July 2013. IE have not introduced routine rotavirus vaccination to date. The aim of this population based ecological study was to evaluate the impact of the rotavirus vaccine on burden of rotavirus disease in NI, and to compare with IE as an unvaccinated control population. This will help determine if the changes seen were due to the rotavirus vaccine, or due to confounding factors. METHODS: A number of population based measures of disease burden were compared in both jurisdictions pre-vaccine (six years; 2007/08-2012/13) and post-vaccine (two years; 2013/14-2014/15). The data sources included national rotavirus surveillance data based on laboratory reports/notifications; hospital admission data; and notifications of gastroenteritis in under 2year olds. RESULTS: In the post-vaccination period, rotavirus incidence in NI dropped by 54% while in IE it increased by 19% compared to the pre-vaccine period. Notifications of gastroenteritis in under 2s in NI declined by 53% and hospital admissions in under 5year olds in NI declined by 40% in the post vaccine period. CONCLUSIONS: This natural experiment demonstrated a significant reduction in rotavirus disease activity post-vaccine introduction in NI with associated reductions in healthcare utilisation, with a concurrent increase in rotavirus disease activity in the non-vaccinated population in IE. These findings support rotavirus vaccination as an effective measure to reduce childhood morbidity.