In this work, the synthesis of limonene lactam starting from limonene epoxide and its subsequent ring‐opening polymerization (ROP) to novel polyamides is presented. Sustainable, biobased materials ...are gaining interest as replacements of conventional, petroleum‐based materials, and even more important, as high‐performance materials for new applications. Terpenes—structurally advanced biobased compounds—are therefore of great interest. In this research, limonene lactam, a novel biobased monomer for preparing sustainable polyamides via ROP, can be synthesized. Limonene lactam possesses an isopropylene and a methyl side group, thus stereocenters posing special challenges and requirements for synthesis, analysis and polymerization. However, these difficult‐to‐synthesize structural elements can generate novel polymers with unique properties, e.g., functionalizability. In this work, a sustainable monomer synthesis is established, and simplified to industrial needs. For the sterically demanding in‐bulk ROP to limonene polyamides, various initiators and conditions are tested. Polyamides with more than 100 monomer units are successfully synthesized and confirmed via nuclear magnetic resonance (NMR) spectroscopy and gel permeations chromatography (GPC). Differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) are used to analyze its thermal properties. In summary, a sustainable monomer synthesis is established, and promising polyamides with intact double bond and interesting thermal properties are achieved.
The synthesis of a lactam from the terpene (+)‐limonene (oxide) and its ring‐opening polymerization to polyamides is presented. Limonene is abundant and can be conveniently extracted from citrus peels, rendering it suitable as sustainable starting material. The resulting biopolymers possess side groups and stereocenters, resulting into, e.g., interesting thermal properties and functionalizability; therefore, they are suitable candidates for high‐performance polyamides.
To assess changes in retinopathy of prematurity (ROP) diagnosis in single and serial retinal images.
Cohort study.
Cases of ROP recruited from the Imaging and Informatics in Retinopathy of ...Prematurity (i-ROP) consortium evaluated by 7 graders.
Seven ophthalmologists reviewed both single and 3 consecutive serial retinal images from 15 cases with ROP, and severity was assigned as plus, preplus, or none. Imaging data were acquired during routine ROP screening from 2011 to 2015, and a reference standard diagnosis was established for each image. A secondary analysis was performed using the i-ROP deep learning system to assign a vascular severity score (VSS) to each image, ranging from 1 to 9, with 9 being the most severe disease. This score has been previously demonstrated to correlate with the International Classification of ROP. Mean plus disease severity was calculated by averaging 14 labels per image in serial and single images to decrease noise.
Grading severity of ROP as defined by plus, preplus, or no ROP.
Assessment of serial retinal images changed the grading severity for > 50% of the graders, although there was wide variability. Cohen's kappa ranged from 0.29 to 1.0, which showed a wide range of agreement from slight to perfect by each grader. Changes in the grading of serial retinal images were noted more commonly in cases of preplus disease. The mean severity in cases with a diagnosis of plus disease and no disease did not change between single and serial images. The ROP VSS demonstrated good correlation with the range of expert classifications of plus disease and overall agreement with the mode class (P = 0.001). The VSS correlated with mean plus disease severity by expert diagnosis (correlation coefficient, 0.89). The more aggressive graders tended to be influenced by serial images to increase the severity of their grading. The VSS also demonstrated agreement with disease progression across serial images, which progressed to preplus and plus disease.
Clinicians demonstrated variability in ROP diagnosis when presented with both single and serial images. The use of deep learning as a quantitative assessment of plus disease has the potential to standardize ROP diagnosis and treatment.
Background Retinopathy of prematurity (ROP) is a proliferative disease of the ocular retinal vasculature in premature infants, being a leading cause of preventable childhood blindness. The COVID-19 ...pandemic serves as an additional barrier to access to care and referral, potentially leading to more cases of advanced stage ROP. Although surgery can be done, ROP at this stage is highly associated with poor functional outcome irrespective of surgery. This case series aims to report advanced stage (stage 5) ROP in premature infants during the COVID-19 pandemic.
MethodsA retrospective case series of medical records of paediatric patients with ROP was performed at Cipto Mangunkusumo National Referral Hospital between March 1, 2020 and December 31, 2021. This case series included new patients that presented to our clinic from March 2020 to December 2021 with stage 5 ROP.
ResultsA total of 19 eyes of 10 patients with stage 5 ROP were included in this study. Mean chronologic age at presentation to our referral centre was 7.0 4.0 months. Upon presentation, all had stage 5 ROP with negative blink reflex to light, and none of the eyes in this cohort underwent surgical intervention. Mean gestational age was 30.3 3.2 weeks and mean birth weight was 1,276.7 366.4 g.
ConclusionThere was an observable surge of stage 5 ROP at our referral centre with irreversible blindness. This highlights the need for proper ROP screening in all hospitals in Indonesia to prevent delay in detection and care of advanced stage ROP.
Cardiac troponin I (cTnI), a gold biomarker for the diagnosis of acute myocardial infarction (AMI), plays a vital role in the early diagnosis, treatment and prognosis analysis of AMI. In this paper, ...an electrochemical biosensor for the highly sensitive determination of cTnI was fabricated based on the dual signal amplification strategy of electron transfer atom transfer radical polymerization (ARGET ATRP) and ring-opening polymerization (ROP) for the first time. Briefly, the thiolate cTnI-aptamer 1, which was bonded to the electrode via Au–S bonds, specifically captured cTnI to the electrode surface. Then, cTnI-aptamer 2 (Apt2) was successfully introduced to the electrode surface to form Apt-cTnI-Apt sandwich structure. Subsequently, the initiator BIBB was connected to Apt2 through bromination reaction, and then the resulting ATRP polymer was employed as a macromolecular initiator for the succeeding reaction. Next, the monomers, α-amino acid-N-carboxylic acid anhydride ferrocene derivatives (NCA-Fc), used for the ROP reaction produced numerous electroactive polymers on the electrode surface. The dual action of ARGET ATRP and ROP significantly improved sensitivity of cTnI biosensor assay, the prepared biosensor displayed a wide linear detection range from 100 fg mL−1 to 100 ng mL−1, with a detection limit of 32.24 fg mL−1. The method exhibited favorable selectivity, simple operation and excellent stability. Furthermore, the biosensor still rendered satisfactory analytical performance in the detection of clinical serum samples, indicating the application potential in clinical diagnosis.
A novel electrochemical biosensor for sensitive detection of cTnI by ARGET ATRP and ROP dual signal amplification strategy, which held the advantages of high sensitivity, applicability, selectivity and simple operation. Display omitted
•A novel electrochemical biosensor was constructed for sensitive assay of cTnI.•The signal was dramatically amplified by the dual action of ARGET ATRP and ROP strategy.•The biosensor showed satisfactory analytical reliability in serum samples.•The strategy can be used as a universal platform for other biomarkers detection.
RHO guanosine triphosphatases are important eukaryotic regulators of cell differentiation and behavior. Plant ROP (RHO of plant) family members activate specific, incompletely characterized ...downstream signaling. The structurally simple land plant Physcomitrium patens is missing homologs of key animal and flowering plant RHO effectors but contains a single CRIB (CDC42/RAC interactive binding)-domain-containing RIC (ROP-interacting CRIB-containing) protein (PpRIC). Protonemal P. patens filaments elongate based on regular division and PpROP-dependent tip growth of apical initial cells, which upon stimulation by the hormone auxin differentiate caulonemal characteristics. PpRIC interacts with active PpROP1, co-localizes with this protein at the plasma membrane at the tip of apical initial cells, and accumulates in the nucleus. Remarkably, PpRIC is not required for tip growth but is targeted to the nucleus to block caulonema differentiation downstream of auxin-controlled gene expression. These observations establish functions of PpRIC in mediating crosstalk between ROP and auxin signaling, which contributes to the maintenance of apical initial cell identity.
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•The PpROP interactor PpRIC is the only homolog of key RHO effectors in P. patens•PpRIC homologs are structurally conserved in most land plants except flowering plants•PpRIC has nuclear functions, while most flowering plant homologs modulate F-actin•PpRIC specifically blocks auxin- and high-light-induced caulonema differentiation
Ntefidou et al. show that RICs, key CRIB-domain effectors of ROP (RHO of plant) GTPases, are represented by few closely related homologs in most land plants but display massive diversification in flowering plants. Whereas most flowering plant RICs modulate cytoplasmic F-actin, moss PpRIC has nuclear functions in maintaining apical initial cell identity.
Nigeria has the third largest incidence of premature birth, after India and China. Most babies that will require treatment for retinopathy of prematurity (ROP) have birth weight (BW) less than 1500g ...and gestational age (GA) less than 32 weeks, with initial eye examination within the first 30 days of life. This report aims to present the findings in three babies with vision threatening ROP that developed at less than 30 days of life. Routine screening for ROP was conducted for three babies. One was born GA 33 weeks, BW 1.6kg, screened for ROP on the 13th day of life, while the other two were a set of twins born at GA of 33 weeks, both BW 1.3kg, screened for ROP first on the 16th day of life. The twins were found CC –BY 4.0 to have arborizing vessels at the initial exam, which progressed to stage 3 pre-plus ROP by the 23rd day of life. The 3rd child had stage -3 plus disease at the first screening, warranting immediate LASER therapy. The screening criteria of Nigeria ROP group is BW ≤ 1500g or GA of ≤ 34 weeks, with the first eye examination within the first 30 days of life. These case reports show that larger babies can also develop sight threatening ROP within the first two weeks of life. There is a need for constant review of ROP screening criteria and timing based on locally available data
To determine the status of proangiogenic factors in the tear fluid of preterm infants with and without retinopathy of prematurity (ROP).
Preterm infants (n = 36) undergoing routine ROP screening ...included in the prospective study were categorized as No-ROP (n = 13, no ROP at any visits), ROP (if ROP was present at first visit; n = 18), or No-ROP to ROP (no disease at first visit, but developed ROP subsequently; n = 5). Infants with ROP were also grouped as progressing (n = 7) and regressing (n = 16) based on ROP evolution between the first and subsequent visits. Schirmer's strips were used to collect tear fluid and proangiogenic factors (VEGF, angiogenin, soluble vascular cell adhesion molecule, and fractalkine) levels (in picograms per milliliter) in tear fluid were measured by multiplex ELISA.
Lower levels of VEGF (135 ± 69; mean ± standard deviation) and higher levels of angiogenin (6568 ± 4975) were observed in infants with ROP compared with infants without ROP (172.5 ± 54.0; 4139 ± 3909) at the first visit. Significantly lower levels of VEGF were observed in the No-ROP to ROP group compared with the No-ROP and ROP groups. The VEGF and angiogenin levels at the first visit were significantly lower in infants with ROP with progressing disease. Angiogenin levels negatively correlated with birth weight and gestational age in ROP. The area under the curve (AUC) and odds ratio (OR) analysis demonstrated that angiogenin/birth weight (AUC = 0.776; OR, 8.6); angiogenin/gestational age (AUC = 0.706; OR, 7.3) and Angiogenin/VEGF (AUC = 0.806; OR, 14.3) ratios were able to differentiated preterm infants with and without ROP.
The association between angiogenin and ROP suggests its possible role in ROP. The ratio of angiogenin level with birth weight, gestational age, and/or VEGF could serve as a potential noninvasive screening biomarker for ROP.
The present article reports a simple and straightforward approach to access thermoresponsive graft copolymers based on lactide (LA) and a methacrylic monomer, 2‐hydroxypropyl methacrylate (HPMA), ...using a synthesized carboxy‐functionalized trithiocarbonate‐based chain transfer agent. One protocol involves a metal‐free simultaneous synthesis through a combination of reversible addition‐fragmentation chain transfer polymerization and organic acid‐catalyzed ring‐opening polymerization, which follows first‐order kinetics. The resulting copolymers with a controlled structure exhibit remarkably narrow molecular weight distributions (Ð < 1.10). Within this framework, the self‐assembly of PHPMA‐g‐PLA graft copolymers (GCs) into nanoparticles (NPs) is demonstrated at concentrations of 0.2 and 0.5 wt.%, respectively. The displacement method, based on the rapid injection of the organic solvent (acetone) into an aqueous medium under vigorous stirring, produces spherical NPs such as micelles, vesicles, or non‐spherical “lumpy rods”. The presence of a pseudo‐thermoresponsive segment (PHPMA) in GCs facilitates stimulus‐responsive self‐assembly behavior. Well‐defined spherical NPs—primarily vesicles of substantial size—develop upon heating above the glass transition temperature (Tg ≈35–36 °C) of the GCs in an acetone–water (80/20 wt.%) mixture. Last, specific interactions between the obtained PHPMA‐g‐PLA nano‐objects and blood proteins in human plasma are studied using isothermal calorimetry.
This article outlines a simple approach for producing thermoresponsive graft copolymers from lactide and 2‐hydroxypropyl methacrylate through a metal‐free simultaneous synthesis involving RAFT polymerization and ROP. Self‐assembly of PHPMA‐g‐PLA copolymers via a displacement method results in the formation of nano‐objects, such as micelles, vesicles, or lumpy rods. Interactions with blood proteins in human plasma are studied using isothermal calorimetry
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Background. The aim of this study was to investigate the effectiveness of the Postnatal Growth and Retinopathy of Prematurity (G-ROP) and Colorado Retinopathy of Prematurity (CO-ROP) models in ...predicting the risk of Retinopathy of Prematurity (ROP) in preterm infants at a tertiary ROP diagnostic and treatment center.
Methods. The G-ROP and CO-ROP models were applied to the study group using the data obtained. The sensitivity and specificity of both models were then calculated.
Results. One hundred and twenty-six infants were included in the study. When the G-ROP model was applied to the study group, the model`s sensitivity at detecting any stage ROP was 88.7%, while it was 93.3% for the treated group. The specificity of the model was 10.9% for any stage ROP, and 11.7% for the treated group. For the CO-ROP model in the same study group, the sensitivity at detecting any stage ROP was 87.3%, while it was 100% for the treated group. The CO-ROP model's specificity was 40% for any stage ROP, and 27.9% for the treated group. When cardiac pathology criteria were introduced to both models, the sensitivity of the G-ROP and CO-ROP models increased to 94.4% and 97.2%, respectively.
Conclusions. It was found that the G-ROP and CO-ROP models are simple and effective models for predicting any degree of ROP development, but that they are unable to be 100% accurate. When the models were modified by introducing cardiac pathology criteria, it was observed that they began to produce more accurate results. Studies with larger groups are needed in order to assess the applicability of the modified criteria.
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Two series of tetravalent titanium catalysts, which include bis(isopropoxide) (1–5) and dichloro-(6–7) compounds, are reported. The compounds are supported by phenoxy-imine type ...proligands (HL1 − HL5) derived from substituted salicylaldehyde and 2-thiophenemethylamine. The synthesized Ti(IV) compounds, which were characterized by NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction studies, exhibited a coordination number six where the Ti(IV) center adopted a distorted octahedral geometry. All the Ti(IV) compounds were screened for the ring-opening polymerization (ROP) of racemic-lactide (rac-LA) and ring-opening copolymerization (ROCOP) of phthalic anhydride (PA) and cyclohexene oxide (CHO) as well as for the ROCOP of CHO with CO2. The bis(isopropoxide) Ti(IV) compounds were active for the ROP of rac-LA and gave atactic (Pr = 0.51) to slightly isotactic-enriched (Pm = 0.59) polylactide (PLA) depending on the substituent attached to the phenolate core. The ROP of rac-LA is proposed to undergo a dissociative coordination-insertion mechanism. All the Ti(IV) compounds (1–7) were active for both types of ROCOP mentioned above, in the presence of a cocatalyst, with the best results obtained with PPNCl Bis(triphenylphosphine)iminium chloride as the cocatalyst. The compound 3 substituted with two chlorine atoms at the phenolate core of salicylaldehyde was most active for these polymerization reactions owning to its fluxional behavior at room temperature.
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