Facile synthesis of carbon nanoparticles from sodium alginate via ultrasonic-assisted nano-precipitation and thermal acid dehydration for ferric ion sensing

Carbon nanoparticles have emerged as a promising alternative to the well-known quantum dots in many biological applications due to their excellent optical properties and biocompatibility. It has received considerable attentions from researchers especially in the aspects of producing these carbon nanomaterials via easier and cheaper synthetic routes. On this motivation, we hereby report an economical and facile synthesis of carbon nanoparticles from alginate via a simple two-step procedure; nano-precipitation through ultrasonication followed by thermal acid carbonisation. Nano-precipitation was first performed on the alginate stock solution to produce nanoparticles with controlled morphology. Precipitation was performed in acidic solution that has coagulated the alginate chains into nanoparticles. Ultrasonic treatment was found crucial to assist the formation of nanoparticles that were more homogenous in the size distribution at around 100 nm. The shape was also more spherical as compared to those without ultrasonic treatment. In the carbonisation step, thermal dehydration was employed using concentrated sulphuric acid that has successfully converted the preformed alginate nanoparticles into carbon nanoparticles. The carbon nanoparticles isolated showed high fluorescence even without further surface passivation. The fluorescence of these carbon nanoparticles were utilised for sensitive and selective sensing of ferric ions and it was evaluated to have a linear analytical dynamic range up to 25 μM with a limit of detection (LOD) as low as 1.06 μM. The system was successfully employed to detect ferric ions in real water sample

A unique “turn-on” fluorescence signalling strategy for highly specific detection of ascorbic acid using carbon dots as sensing probe

Carbon dots (CDs) that showed strong blue fluorescence were successfully synthesised from sodium alginate via furnace pyrolysis. The single step pyrolytic synthesis was simple to perform while yielded CDs with high photostability, good water solubility and minimum by-products. In order to design the probe with “turn-on” sensing capability, the CDs were screened against a series of metal cations to first “turn-off” the fluorescence. It was found that ferric ions (Fe3þ) were most responsive and effective in quenching the fluorescence of CDs. Based on this observation, the conditioning of the probe was performed to ensure the fluorescence was completely quenched, while not overloading the system with Fe3þ. At the optimised condition, the CDs-Fe3þ mixture served as a highly specific detection probe for ascorbic acid (AA). The analytical potential of the probe was evaluated and showed a good linear range of response for AA concentration of 24–40 μg/mL. The selectivity study against other possible co-existing species was carried out and proved that our unique “turn-on” fluorescence signalling strategy was highly effective and selective towards AA as the target analyte. The probe was demonstrated for quantification of AA in real samples, which was the commercially available vitamin C supplement. The result showed good accuracy with minimum deviation from standard method adopted for validation purpose

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely

Facile synthesis of carbon nanoparticles from sodium alginate via ultrasonic-assisted nano-precipitation and thermal acid dehydration for ferric ion sensing

Carbon nanoparticles have emerged as a promising alternative to the well-known quantum dots in many biological applications due to their excellent optical properties and biocompatibility. It has received considerable attentions from researchers especially in the aspects of producing these carbon nanomaterials via easier and cheaper synthetic routes. On this motivation, we hereby report an economical and facile synthesis of carbon nanoparticles from alginate via a simple two-step procedure; nano-precipitation through ultrasonication followed by thermal acid carbonisation. Nano-precipitation was first performed on the alginate stock solution to produce nanoparticles with controlled morphology. Precipitation was performed in acidic solution that has coagulated the alginate chains into nanoparticles. Ultrasonic treatment was found crucial to assist the formation of nanoparticles that were more homogenous in the size distribution at around 100 nm. The shape was also more spherical as compared to those without ultrasonic treatment. In the carbonisation step, thermal dehydration was employed using concentrated sulphuric acid that has successfully converted the preformed alginate nanoparticles into carbon nanoparticles. The carbon nanoparticles isolated showed high fluorescence even without further surface passivation. The fluorescence of these carbon nanoparticles were utilised for sensitive and selective sensing of ferric ions and it was evaluated to have a linear analytical dynamic range up to 25 μM with a limit of detection (LOD) as low as 1.06 μM. The system was successfully employed to detect ferric ions in real water sample

A sustainable alternative to synthesis optical sensing receptor for the detection of metal ions

The development of new optical sensing receptors not only need to focus on its sensitivity and selectivity aspects, but should also emphasis on the sustainability of the development as a whole. This report proposed a green synthesis method to produce fluorescent carbon nanoparticles via thermal carbonisation of orange peels. This is a sustainable option since used agricultural waste as starting precursor, involved no excess or toxic chemical reagents, produced low or no waste side product, and employed simple synthesis steps. Parameters governing the precursor conversion into carbon rich residues were investigated and found that the optimum carbonisation occurs at the temperature range of 300-350 °C for an exposure time of 2 h. The carbon residue was then grinded into fine nanoparticles, dispersed in water and followed by sonication to promote better dispersion in water. Colloidal suspension remaining in the aliquot after centrifugation for 15 min at 13,400 rpm was collected and found to show strong fluorescence emission at 435 nm, when excited at the optimum wavelength of 325 nm. This unique optical property has been utilised for sensing application since the fluorescence intensity was significantly quenched in the presence of heavy metal ions. Analytical characteristic was evaluated using standard Stern-Volmer equation and the limit of detection was evaluated to be significantly low that enable the practical utilisation for quantification applications. It can serve as a less toxic fluorophore candidate to replace some of those existing quantum dots or dyes that are less sustainable in nature or in terms of its development approach

Expanding the genotypic and phenotypic spectrum in a diverse cohort of 104 individuals with Wiedemann-Steiner syndrome.

Wiedemann-Steiner syndrome (WSS) is an autosomal dominant disorder caused by monoallelic variants in KMT2A and characterized by intellectual disability and hypertrichosis. We performed a retrospective, multicenter, observational study of 104 individuals with WSS from five continents to characterize the clinical and molecular spectrum of WSS in diverse populations, to identify physical features that may be more prevalent in White versus Black Indigenous People of Color individuals, to delineate genotype-phenotype correlations, to define developmental milestones, to describe the syndrome through adulthood, and to examine clinicians' differential diagnoses. Sixty-nine of the 82 variants (84%) observed in the study were not previously reported in the literature. Common clinical features identified in the cohort included: developmental delay or intellectual disability (97%), constipation (63.8%), failure to thrive (67.7%), feeding difficulties (66.3%), hypertrichosis cubiti (57%), short stature (57.8%), and vertebral anomalies (46.9%). The median ages at walking and first words were 20 months and 18 months, respectively. Hypotonia was associated with loss of function (LoF) variants, and seizures were associated with non-LoF variants. This study identifies genotype-phenotype correlations as well as race-facial feature associations in an ethnically diverse cohort, and accurately defines developmental trajectories, medical comorbidities, and long-term outcomes in individuals with WSS. Keywords: KMT2A; MLL1; Wiedemann-Steiner syndrome; hypertrichosis; syndromic intellectual disability; syndromic short stature.Institute for Translational Medicine and Therapeutics of the Perelman School of Medicine at the University of Pennsylvania United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Center for Advancing Translational Sciences (NCATS) United States Department of Health & Human Services National Institutes of Health (NIH) - USA Hartwell Foundatio

Global economic burden of unmet surgical need for appendicitis

Background There is a substantial gap in provision of adequate surgical care in many low- and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially