RESUMO
BACKGROUND: A range of sacroiliac joint (SIJ) MRI protocols are used in clinical practice but not all were specifically designed for diagnostic ascertainment. This can be confusing and no standard diagnostic SIJ MRI protocol is currently accepted worldwide. OBJECTIVE: To develop a standardised MRI image acquisition protocol (IAP) for diagnostic ascertainment of sacroiliitis. METHODS: 13 radiologist members of Assessment of SpondyloArthritis International Society (ASAS) and the SpondyloArthritis Research and Treatment Network (SPARTAN) plus two rheumatologists participated in a consensus exercise. A draft IAP was circulated with background information and online examples. Feedback on all issues was tabulated and recirculated. The remaining points of contention were resolved and the revised IAP was presented to the entire ASAS membership. RESULTS: A minimum four-sequence IAP is recommended for diagnostic ascertainment of sacroiliitis and its differential diagnoses meeting the following requirements. Three semicoronal sequences, parallel to the dorsal cortex of the S2 vertebral body, should include sequences sensitive for detection of (1) changes in fat signal and structural damage with T1-weighting; (2) active inflammation, being T2-weighted with fat suppression; (3) bone erosion optimally depicting the bone-cartilage interface of the articular surface and (4) a semiaxial sequence sensitive for detection of inflammation. The IAP was approved at the 2022 ASAS annual meeting with 91% of the membership in favour. CONCLUSION: A standardised IAP for SIJ MRI for diagnostic ascertainment of sacroiliitis is recommended and should be composed of at least four sequences that include imaging in two planes and optimally visualise inflammation, structural damage and the bone-cartilage interface.
RESUMO
The syntheses and characterisation of the 4-[{[4-({n-[4-(4-cyanophenyl)phenyl]-n-yl}oxy)phenyl]-methylidene}amino]phenyl-4-alkoxybenzoates (CBnOIBeOm) are reported with n=8 and 10 and m=1-10. The two series display fascinating liquid crystal polymorphism. All twenty reported homologues display an enantiotropic nematic (N) phase at high temperature. When the length of the spacer (n) is greater than that of the terminal chain (m), the twist-bend nematic (NTB) phase is observed at temperatures below the N phase. As the length of the terminal chain is increased and extends beyond the length of the spacer up to three smectic phases are observed on cooling the N phase. One of these smectic phases has been assigned as the rare twist-bend smectic C subphase, the SmCTB-α phase. In all the smectic phases, a monolayer packing arrangement is seen, and this is attributed to the anti-parallel associations of the like mesogenic units.
RESUMO
OBJECTIVE: We examined whether the risk of stillbirth was related to ambient air pollution in a UK population. DESIGN: Prospective case-control study. SETTING: Forty-one maternity units in the UK. POPULATION: Women who had a stillbirth ≥28 weeks' gestation (n = 238) and women with an ongoing pregnancy at the time of interview (n = 597). METHODS: Secondary analysis of data from the Midlands and North of England Stillbirth case-control study only including participants domiciled within 20 km of fixed air pollution monitoring stations. Pollution exposure was calculated using pollution climate modelling data for NO2 , NOx and PM2.5 . The association between air pollution exposure and stillbirth risk was assessed using multivariable logistic regression adjusting for household income, maternal body mass index (BMI), maternal smoking, Index of Multiple Deprivation quintile and household smoking and parity. MAIN OUTCOME MEASURE: Stillbirth. RESULTS: There was no association with whole pregnancy ambient air pollution exposure and stillbirth risk, but there was an association with preconceptual NO2 exposure (adjusted odds ratio [aOR] 1.06, 95% CI 1.01-1.08 per microg/m3 ). Risk of stillbirth was associated with maternal smoking (aOR 2.54, 95% CI 1.38-4.71), nulliparity (aOR 2.16, 95% CI 1.55-3.00), maternal BMI (aOR 1.05, 95% CI 1.01-1.08) and placental abnormalities (aOR 4.07, 95% CI 2.57-6.43). CONCLUSIONS: Levels of ambient air pollution exposure during pregnancy in the UK, all of were beneath recommended thresholds, are not associated with an increased risk of stillbirth. Periconceptual exposure to NO2 may be associated with increased risk but further work is required to investigate this association.
Assuntos
Poluentes Atmosféricos , Poluição do Ar , Feminino , Gravidez , Humanos , Natimorto/epidemiologia , Estudos de Casos e Controles , Dióxido de Nitrogênio/efeitos adversos , Dióxido de Nitrogênio/análise , Placenta , Poluição do Ar/efeitos adversos , Inglaterra/epidemiologia , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/análiseRESUMO
OBJECTIVE: To investigate associations of the Fetal Pillow® with maternal and neonatal morbidity. DESIGN: Retrospective cohort. SETTING: Two tertiary maternity units, New Zealand. POPULATION OR SAMPLE: Full dilatation singleton, term, cephalic caesarean section, with three comparisons: at Unit A (1) before versus after introduction of the Fetal Pillow® (1 Jaunary 2016-31 October 2021); (2) with versus without the Fetal Pillow® after introduction (27 July 2017-31 October 2021); and (3) between Unit A and Unit B during the same time period (1 January 2019-31 October 2021). The Fetal Pillow® is unavailable at Unit B. METHODS: Cases were ascertained and clinical data were extracted from electronic clinical databases and records. Outcome data were adjusted and presented as adjusted odds ratios (aOR) with 95% CI. MAIN OUTCOME MEASURES: Primary outcome "any" uterine incision extension; secondary outcomes included major extension (into adjacent structures), and a composite neonatal outcome. RESULTS: In all, 1703 caesareans were included; 375 with the device and 1328 without. Uterine incision extension rates were: at Unit A before versus after introduction: 26.8% versus 24.8% (aOR 0.88, 95% CI 0.65-1.19); at Unit A with the Fetal Pillow® versus without: 26.1% versus 23.8% (aOR 1.14, 95% CI 0.83-1.57); and at Unit A versus Unit B: 24.2% versus 29.2% (aOR 0.73, 95% CI 0.54-0.99). No differences were found in major extensions, or neonatal composite outcome. CONCLUSIONS: Despite the relatively large size of this study, it could not rule out either a positive or a negative association between use of the Fetal Pillow® and uterine extensions, major uterine incision extensions, and neonatal morbidity. Randomised controlled trial evidence is required to assess efficacy.
Assuntos
Cesárea , Humanos , Feminino , Gravidez , Estudos Retrospectivos , Cesárea/estatística & dados numéricos , Recém-Nascido , Adulto , Nova Zelândia , Primeira Fase do Trabalho de PartoRESUMO
INTRODUCTION: Birth at early term (37+0-38+6 completed gestational weeks [GW] and additional days) is associated with adverse neonatal outcomes compared with waiting to ≥39 GW. Most studies report outcomes after elective cesarean section or a mix of all modes of births; it is unclear whether these adverse outcomes apply to early-term babies born after induction of labor (IOL). We aimed to determine, in women with a non-urgent induction indication (elective/planned >48 h in advance), if IOL at early and late term was associated with adverse neonatal and maternal outcomes compared with IOL at full term. MATERIAL AND METHODS: An observational cohort study as a secondary analysis of a multicenter randomized controlled trial of 1087 New Zealand women with a planned IOL ≥37+0 GW. Multivariable logistic regression was used to analyze neonatal and maternal outcomes in relation to gestational age; 37+0-38+6 (early term), 39+0-40+6 (full term) and ≥41+0 (late term) GW. Neonatal outcome analyses were adjusted for sex, birthweight, mode of birth and induction indication, and maternal outcome analyses for parity, age, body mass index and induction method. The primary neonatal outcome was admission to neonatal intensive care unit (NICU) for >4 hours; the primary maternal outcome was cesarean section. RESULTS: Among the 1087 participants, 266 had IOL at early term, 480 at full term, and 341 at late term. Babies born following IOL at early term had increased odds for NICU admission for >4 hours (adjusted odds ratio [aOR] 2.16, 95% confidence intervals (CI) 1.16-4.05), compared with full term. Women having IOL at early term had no difference in emergency cesarean rates but had an increased need for a second induction method (aOR 1.70, 95% CI 1.15-2.51) and spent 4 h longer from start of IOL to birth (Hodges-Lehmann estimator 4.10, 95% CI 1.33-6.95) compared with those with IOL at full term. CONCLUSIONS: IOL for a non-urgent indication at early term was associated with adverse neonatal and maternal outcomes and no benefits compared with IOL at full term. These findings support international guidelines to avoid IOL before 39 GW unless there is an evidence-based indication for earlier planned birth and will help inform women and clinicians in their decision-making about timing of IOL.
Assuntos
Cesárea , Trabalho de Parto Induzido , Recém-Nascido , Gravidez , Feminino , Humanos , Trabalho de Parto Induzido/métodos , Idade Gestacional , Estudos de Coortes , Modelos Logísticos , Estudos RetrospectivosRESUMO
OBJECTIVES: To determine the prevalence of eczema among children in New Zealand. METHODS: Population-based retrospective observational study utilising national pharmaceutical dispensing records for topical corticosteroids and emollients for all New Zealand children aged 0-14 years from 1st January 2006 to 31st December 2019. Data are reported using descriptive statistics, with comparisons between ethnicities and socioeconomic quintiles undertaken with rate ratios. RESULTS: Based on dispensing data, the prevalence of eczema for New Zealand children aged 0-14 years in 2018 was 14.0% (95% CI 14.0%-14.1%), with prevalence decreasing in older age groups (children aged <1 year 26.0% (25.6%-26.4%); children aged 10-14 years 8.8% (8.7%-8.9%)). Prevalence was higher in Pacific children (23.6% (23.3%-24.0%)), but slightly lower in Maori children (13.2% (13.0%-13.3%)). CONCLUSION: Eczema is a common condition affecting a considerable proportion of children in New Zealand. This study provides nationwide paediatric prevalence data for New Zealand, and highlights the increased burden of eczema in Pacific children. Inequity in dispensing of topical corticosteroids is postulated to explain the reduced rates found for Maori children compared to previous studies. These results support the need for further research to determine factors contributing to differing eczema prevalence rates in New Zealand.
RESUMO
Fetal growth restriction (FGR) and maternal supine going-to-sleep position are both risk factors for late stillbirth. This study aimed to use magnetic resonance imaging (MRI) to quantify the effect of maternal supine position on maternal-placental and fetoplacental blood flow, placental oxygen transfer and fetal oxygenation in FGR and healthy pregnancies. Twelve women with FGR and 27 women with healthy pregnancies at 34-38 weeks' gestation underwent MRI in both left lateral and supine positions. Phase-contrast MRI and a functional MRI technique (DECIDE) were used to measure blood flow in the maternal internal iliac arteries (IIAs) and umbilical vein (UV), placental oxygen transfer (placental flux), fetal oxygen saturation (FO2 ), and fetal oxygen delivery (delivery flux). The presence of FGR, compared to healthy pregnancies, was associated with a 7.8% lower FO2 (P = 0.02), reduced placental flux, and reduced delivery flux. Maternal supine positioning caused a 3.8% reduction in FO2 (P = 0.001), and significant reductions in total IIA flow, placental flux, UV flow and delivery flux compared to maternal left lateral position. The effect of maternal supine position on fetal oxygen delivery was independent of FGR pregnancy, meaning that supine positioning has an additive effect of reducing fetal oxygenation further in women with FGR, compared to women with appropriately grown for age pregnancies. Meanwhile, the effect of maternal supine positioning on placental oxygen transfer was not independent of the effect of FGR. Therefore, growth-restricted fetuses, which are chronically hypoxaemic, experience a relatively greater decline in oxygen transfer when mothers lie supine in late gestation compared to appropriately growing fetuses. KEY POINTS: Fetal growth restriction (FGR) is the most common risk factor associated with stillbirth, and early recognition and timely delivery is vital to reduce this risk. Maternal supine going-to-sleep position is found to increase the risk of late stillbirth but when combined with having a FGR pregnancy, maternal supine position leads to 15 times greater odds of stillbirth compared to supine sleeping with appropriately grown for age (AGA) pregnancies. Using MRI, this study quantifies the chronic hypoxaemia experienced by growth-restricted fetuses due to 13.5% lower placental oxygen transfer and 26% lower fetal oxygen delivery compared to AGA fetuses. With maternal supine positioning, there is a 23% reduction in maternal-placental blood flow and a further 14% reduction in fetal oxygen delivery for both FGR and AGA pregnancies, but this effect is proportionally greater for growth-restricted fetuses. This knowledge emphasises the importance of avoiding supine positioning in late pregnancy, particularly for vulnerable FGR pregnancies.
Assuntos
Placenta , Circulação Placentária , Gravidez , Feminino , Humanos , Placenta/diagnóstico por imagem , Placenta/irrigação sanguínea , Retardo do Crescimento Fetal/diagnóstico por imagem , Natimorto , Imageamento por Ressonância Magnética , OxigênioRESUMO
A critical end point above which an isotropic phase continuously evolves into a polar (ferroelectric) nematic phase with an increasing electric field is found in a ferroelectric nematic liquid crystalline material. The critical end point is approximately 30 K above the zero-field transition temperature from the isotropic to nematic phase and at an electric field of the order of 10 V/µm. Such systems are interesting from the application point of view because a strong birefringence can be induced in a broad temperature range in an optically isotropic phase.
RESUMO
The synthesis and characterisation of two series of low molar mass mesogens, the (4-nitrophenyl) 2-alkoxy-4-(4-methoxybenzoyl)oxybenzoates (NT3.m) and the (3-fluoro-4-nitrophenyl) 2-alkoxy-4-(4-methoxybenzoyl)oxybenzoates (NT3F.m), are reported in order to investigate the effect of changing the position of a lateral alkoxy chain from the methoxy-substituted terminal ring to the central phenyl ring in these two series of materials based on RM734. All members of the NT3.m series exhibited a conventional nematic phase, N, which preceded the ferroelectric nematic phase, NF , whereas all the members of the NT3F.m series exhibited direct NF -I transitions except for NT3F.1 which also exhibited an N phase. These materials cannot be described as wedge-shaped, yet their values of the ferroelectric nematic-nematic transition temperature, T N F N ${{_{{\rm N}{_{{\rm F}}}{\rm N}}}}$ , exceed those of the corresponding materials with the lateral alkoxy chain located on the methoxy-substituted terminal ring. In part, this may be attributed to the effect that changing the position of the lateral alkoxy chain has on the electronic properties of these materials, specifically on the electron density associated with the methoxy-substituted terminal aromatic ring. The value of TNI decreased with the addition of a fluorine atom ortho to the nitro group in NT3F.1, however, the opposite behaviour was found when the transition temperatures of the NF phase were compared which are higher for the NT3F.m series. This may reflect a change in the polarity and polarizability of the NT3F.m series compared to the NT3.m series. Therefore, it is suggested that, rather than simply promoting a tapered shape, the role of the lateral chain in inhibiting anti-parallel associations and its effect on the electronic properties of the molecules are the key factors in driving the formation of the NF phase.
RESUMO
The inclusion of secondary and tertiary benzanilide-based mesogenic groups into liquid crystal dimers is reported as a means to develop new materials. Furthermore, substitution at the nitrogen atom is shown to introduce an additional synthetic 'handle' to modify the molecular structure of the tertiary materials. The design of these materials has proved challenging due to the strong preferences of 3° benzanilides for the E amide conformation. In this work, lateral substitution is used to modify the conformational preferences of the amide linkage and promote liquid crystallinity for a series of N-methyl benzanilide dimers. As the proportion of the E conformer decreases, the nematic-isotropic transition temperatures increase, and enantiotropic nematic behaviour is observed. We also report the synthesis and characterisation of the analogous 2° benzanilide-based materials, which show nematic and twist-bend nematic behaviour. This approach highlights the effects that seemingly small structural modifications, such as the inclusion and position of a methyl group, can have on molecular shape and hence, liquid crystalline behaviour.
RESUMO
Non-symmetric lactate-based chiral liquid crystal dimers containing an odd-membered spacer are shown to exhibit a chiral twist-bend nematic phase which is stable on cooling to room temperature. A comparison of racemic and optically pure materials reveals that the pitch length in the N*TB phase is not influenced by molecular chirality, whereas the nematic-twist-bend nematic transition temperature is increased.
RESUMO
The front cover artwork is provided by Dr Rebecca Walker of the Liquid Crystals Group at the University of Aberdeen. The image is a cartoon depiction of the formation of the heliconical chiral twist-bend nematic phase (N*TB ) from its constituent bent molecules. The presence of a single enantiomer of the chiral, lactate-based liquid crystal dimers biases the formation of helices with only one handedness, unlike in the conventional NTB phase, observed for achiral molecules, for which the left- and right-handed helices are doubly degenerate. Read the full text of the Research Article at 10.1002/cphc.202200807.
RESUMO
OBJECTIVE: Identify independent and novel risk factors for late-preterm (28-36 weeks) and term (≥37 weeks) stillbirth and explore development of a risk-prediction model. DESIGN: Secondary analysis of an Individual Participant Data (IPD) meta-analysis investigating modifiable stillbirth risk factors. SETTING: An IPD database from five case-control studies in New Zealand, Australia, the UK and an international online study. POPULATION: Women with late-stillbirth (cases, n = 851), and ongoing singleton pregnancies from 28 weeks' gestation (controls, n = 2257). METHODS: Established and novel risk factors for late-preterm and term stillbirth underwent univariable and multivariable logistic regression modelling with multiple sensitivity analyses. Variables included maternal age, body mass index (BMI), parity, mental health, cigarette smoking, second-hand smoking, antenatal-care utilisation, and detailed fetal movement and sleep variables. MAIN OUTCOME MEASURES: Independent risk factors with adjusted odds ratios (aOR) for late-preterm and term stillbirth. RESULTS: After model building, 575 late-stillbirth cases and 1541 controls from three contributing case-control studies were included. Risk factor estimates from separate multivariable models of late-preterm and term stillbirth were compared. As these were similar, the final model combined all late-stillbirths. The single multivariable model confirmed established demographic risk factors, but additionally showed that fetal movement changes had both increased (decreased frequency) and reduced (hiccoughs, increasing strength, frequency or vigorous fetal movements) aOR of stillbirth. Poor antenatal-care utilisation increased risk while more-than-adequate care was protective. The area-under-the-curve was 0.84 (95% CI 0.82-0.86). CONCLUSIONS: Similarities in risk factors for late-preterm and term stillbirth suggest the same approach for risk-assessment can be applied. Detailed fetal movement assessment and inclusion of antenatal-care utilisation could be valuable in late-stillbirth risk assessment.
Assuntos
Cuidado Pré-Natal , Natimorto , Recém-Nascido , Gravidez , Feminino , Humanos , Natimorto/epidemiologia , Natimorto/psicologia , Fatores de Risco , Idade Materna , Cuidado Pré-Natal/psicologia , ParidadeRESUMO
INTRODUCTION: Maternal perception of fetal movements during pregnancy are reassuring; however, the perception of a reduction in movements are concerning to women and known to be associated with increased odds of late stillbirth. Prior to full term, little evidence exists to provide guidelines on how to proceed unless there is an immediate risk to the fetus. Increased strength of movement is the most commonly reported perception of women through to full term, but perception of movement is also hypothesized to be influenced by fetal size. The study aimed to assess the pattern of maternal perception of strength and frequency of fetal movement by gestation and customized birthweight quartile in ongoing pregnancies. A further aim was to assess the association of stillbirth to perception of fetal movements stratified by customized birthweight quartile. MATERIAL AND METHODS: This analysis was an individual participant data meta-analyses of five case-control studies investigating factors associated with stillbirth. The dataset included 851 cases of women with late stillbirth (>28 weeks' gestation) and 2257 women with ongoing pregnancies who then had a liveborn infant. RESULTS: The frequency of prioritized fetal movement from 28 weeks' gestation showed a similar pattern for each quartile of birthweight with increased strength being the predominant perception of fetal movement through to full term. The odds of stillbirth associated with reduced fetal movements was increased in all quartiles of customized birthweight centiles but was notably greater in babies in the lowest two quartiles (Q1: adjusted OR: 9.34, 95% CI: 5.43, 16.06 and Q2: adjusted OR: 6.11, 95% CI: 3.11, 11.99). The decreased odds associated with increased strength of movement was present for all customized birthweight quartiles (adjusted OR range: 0.25-0.56). CONCLUSIONS: Increased strength of fetal movements in late pregnancy is a positive finding irrespective of fetal size. However, reduced fetal movements are associated with stillbirth, and more so when the fetus is small.
Assuntos
Movimento Fetal , Natimorto , Gravidez , Feminino , Humanos , Peso ao Nascer , Terceiro Trimestre da Gravidez , PercepçãoRESUMO
Methylthioninium chloride (MTC) is a standard treatment for methaemoglobinaemia. A preparation of reduced MTC has been reported to increase blood oxygen saturation (SpO2) and lower respiratory rates in patients with severe COVID-19. We have developed a stable form of reduced methylthionine (hydromethylthionine-mesylate, HMTM) having a benign safety profile in two Phase 3 trials in Alzheimer's disease. The aim of this prospective study was to determine the effects of oral HMTM on SpO2 and methaemoglobin (metHb) levels in a cohort of patients with mild hypoxaemia not due to COVID-19. Eighteen participants randomised to a single dose of 4, 75, 100 or 125 mg doses of HMTM had SpO2 levels below 94% at baseline. Patients were routinely monitored by pulse oximetry after 4 h, and after 2 and 6 weeks of twice daily dosing. Significant ~3% increases in SpO2 occurred within 4 h and were sustained over 2 and 6 weeks with no dose differences. There were small dose-dependent increases (0.060-0.162%) in metHb levels over 2 to 6 weeks. Minimum-energy computational chemistry revealed that HMT can bind within 2.10 Å of heme iron by donating a pair of electrons from the central nitrogen of HMT to d orbitals of heme iron, but with lower affinity than oxygen. In conclusion, HMTM can increase SpO2 without reducing metHb by acting as a strong displaceable field ligand for heme iron. We hypothesise that this facilitates a transition from the low oxygen affinity T-state of heme to the higher affinity R-state. HMTM has potential as an adjunctive treatment for hypoxaemia.
Assuntos
COVID-19 , Azul de Metileno , Humanos , Estudos Prospectivos , Oxigênio , Heme , Metemoglobina , Hipóxia , FerroRESUMO
OBJECTIVE: To examine the effects of infant sofa-sleeping, recent use by caregivers of alcohol, cannabis, and/or other drugs, and bed type and pillows, on the risk of sudden unexpected death in infancy (SUDI) in New Zealand. STUDY DESIGN: A nationwide prospective case-control study was implemented between March 2012 and February 2015. Data were collected during interviews with parents/caregivers. "Hazards" were defined as infant exposure to 1 or more of sofa-sleeping and recent use by caregivers of alcohol, cannabis, and other drugs. The interaction of hazards with tobacco smoking in pregnancy and bed sharing, including for very young infants, and the difference in risk for Maori and non-Maori infants, also were assessed. RESULTS: The study enrolled 132 cases and 258 controls. SUDI risk increased with infant sofa-sleeping (imputed aOR [IaOR] 24.22, 95% CI 1.65-356.40) and with hazards (IaOR 3.35, 95% CI 1.40-8.01). The SUDI risk from the combination of tobacco smoking in pregnancy and bed sharing (IaOR 29.0, 95% CI 10.10-83.33) increased with the addition of 1 or more hazards (IaOR 148.24, 95% CI 15.72-1398), and infants younger than 3 months appeared to be at greater risk (IaOR 450.61, 95% CI 26.84-7593.14). CONCLUSIONS: Tobacco smoking in pregnancy and bed sharing remain the greatest SUDI risks for infants and risk increases further in the presence of sofa-sleeping or recent caregiver use of alcohol and/or cannabis and other drugs. Continued implementation of effective, appropriate programs for smoking cessation, safe sleep, and supplying safe sleep beds is required to reduce New Zealand SUDI rates and SUDI disparity among Maori.
Assuntos
Morte Súbita do Lactente , Roupas de Cama, Mesa e Banho , Leitos , Estudos de Casos e Controles , Feminino , Humanos , Lactente , Gravidez , Fatores de Risco , Sono , Morte Súbita do Lactente/epidemiologia , Morte Súbita do Lactente/etiologiaRESUMO
The synthesis and characterisation of the 1-(4-cyanobiphenyl-4'-yl)-10-(4-alkylanilinebenzylidene-4'-oxy)decanes (CB10O·m) are reported. This series shows a rich liquid crystal polymorphism including twist-bend nematic and smectic phases. All the homologues reported exhibit an enantiotropic conventional nematic phase. For the homologues with m ≤ 10, the local packing in the nematic phases and the layer spacing in the smectic phases indicates an intercalated arrangement of the molecules. An intercalated smectic CA phase is observed if m/11 ≈ 0.5. Either side of this condition, the twist-bend nematic phase is observed, a novel pattern of behaviour for a series on increasing a terminal chain length. For longer chain lengths, m = 12, 14, 16 and 18, two twist-bend smectic C (SmCTB) phases are observed, and the packing of the molecules is now of a bilayer-type. The higher temperature variant is termed SmCTB-SH in which SH (single helix) refers to the presence of a short, distorted clock-type helix. In the lower temperature SmCTB-DH phase, an additional longer helix is superimposed on the short one, and DH denotes double helix.
RESUMO
Dietary pattern analysis is typically based on dimension reduction and summarises the diet with a small number of scores. We assess 'joint and individual variance explained' (JIVE) as a method for extracting dietary patterns from longitudinal data that highlights elements of the diet that are associated over time. The Auckland Birthweight Collaborative Study, in which participants completed an FFQ at ages 3·5 (n 549), 7 (n 591) and 11 (n 617), is used as an example. Data from each time point are projected onto the directions of shared variability produced by JIVE to yield dietary patterns and scores. We assess the ability of the scores to predict future BMI and blood pressure measurements of the participants and make a comparison with principal component analysis (PCA) performed separately at each time point. The diet could be summarised with three JIVE patterns. The patterns were interpretable, with the same interpretation across age groups: a vegetable and whole grain pattern, a sweets and meats pattern and a cereal v. sweet drinks pattern. The first two PCA-derived patterns were similar across age groups and similar to the first two JIVE patterns. The interpretation of the third PCA pattern changed across age groups. Scores produced by the two techniques were similarly effective in predicting future BMI and blood pressure. We conclude that when data from the same participants at multiple ages are available, JIVE provides an advantage over PCA by extracting patterns with a common interpretation across age groups.
Assuntos
Dieta , Comportamento Alimentar , Humanos , Pré-Escolar , Inquéritos e Questionários , Comportamento Alimentar/fisiologia , Verduras , Carne , Análise de Componente PrincipalRESUMO
We synthesized the liquid crystal dimer and trimer members of a series of flexible linear oligomers and characterized their microscopic and nanoscopic properties using resonant soft X-ray scattering and a number of other experimental techniques. On the microscopic scale, the twist-bend phases of the dimer and trimer appear essentially identical. However, while the liquid crystal dimer exhibits a temperature-dependent variation of its twist-bend helical pitch varying from 100 to 170 Å on heating, the trimer exhibits an essentially temperature-independent pitch of 66 Å, significantly shorter than those reported for other twist-bend forming materials in the literature. We attribute this to a specific combination of intrinsic conformational bend of the trimer molecules and a sterically favorable intercalation of the trimers over a commensurate fraction (two-thirds) of the molecular length. We develop a geometric model of the twist-bend phase for these materials with the molecules arranging into helical chain structures, and we fully determine their respective geometric parameters.
RESUMO
OBJECTIVE: To assess speech outcomes at five and ten years of age in a nationwide study of children with orofacial cleft. DESIGN: Prospective study. PARTICIPANTS: Children born with orofacial cleft and having primary surgery in New Zealand. Speech samples were available for 151 five-year-old, and 163 ten-year-old children. MAIN OUTCOME MEASURES: Intelligibility, Acceptability, Velopharyngeal function, Hypernasality, Hyponasality, severity of airflow evaluated by perceptual speech assessment (using the standardised Rhinocleft assessment), and overall assessment of requirement for clinical intervention. RESULTS: A large proportion of five-year-old children had speech that was considered to be not completely intelligible, was not acceptable, and had inadequate velopharyngeal function. The noted deficiencies led to a clinical judgement that further speech and/or surgical intervention was required in 85% with cleft lip and palate, 65% with cleft palate and 26% with cleft lip. The proportion of children with poor speech outcomes in the ten-year-old children was lower, though of clinical importance, further intervention required for 25% with CLP, 15% with CP and 3% with CL. The number of sound production errors in both age groups followed the same pattern with fewest in those with CL and most in those with CLP. CONCLUSIONS: A significant proportion of children with orofacial cleft were found to have poor speech outcomes requiring further treatment. The outcomes are poor compared to centres reported in the UK and Scandinavia. New Zealand requires a review of the current services for individuals born with cleft to improve speech outcomes and interdisciplinary care.