Effective recycling of disposable medical face masks for sustainable green concrete via a new fiber hybridization technique.

Global public response to the COVID-19 (SARS-CoV-2) pandemic is highly focused on human health. However, conservationists have cautioned of unprecedented threats to the natural environment from a new type of non-biodegradable microplastic waste resulting from extensive use of disposable medical face masks (DMFMs). Thus, this waste must be recycled in an eco-friendly manner on an urgent basis. In this research, we developed a new environmentally friendly recycling technique using waste DMFMs in sustainable green concrete. More explicitly, a new fiber hybridization approach has been introduced in which two types of fibers namely DMFM fiber and basalt fiber (BF) were incorporated into fiber reinforced recycled aggregate concrete (FRAC). The volume fractions of DMFM fiber were 0%, 0.1%, and 0.2% and the volume fractions of BF were 0%, 0.25%, and 0.5%. In addition, two mineral admixtures (fly ash and ground granulated blast furnace slag) were also used. Test results indicated increase of approximately 12% in compressive strength, 26% in split tensile strength, and 60% in flexural strength of FRAC containing hybrid fibers and mineral admixtures. The density and ultra-sonic pulse velocity (UPV) of DMFM fiber- and BF-modified FRAC ranged from 2406-2433 kg/m3 and 4502-4541 m/s, respectively, which meets structural concrete requirements. The water absorption rate gradually increased with an increase in the volume fractions of fibers but remained within the allowable water absorption limit for construction materials. Lastly, the microstructure investigation indicated excellent concrete quality, improved interfacial transition zones (ITZs), and good compatibility of host concrete matrix with both DMFM fiber and BF that correlates well with the experimental results reported in this study.

Health information needs of 1000 midlife Singaporean women.

OBJECTIVES: Due to demographic changes, aging is a health priority. We aimed to identify midlife women's perceived health information needs and the preferred method(s) of information delivery. METHODS: A questionnaire was offered to women, aged 45-69 years, attending gynecological clinics during April/May 2016, collecting age and ethnicity data. Participants were asked to indicate important midlife health topics out of 26 topics, including 'other'. For each topic, six delivery options were offered. Age was stratified by 5-year intervals. Associations with age and ethnicity were examined using Pearson's chi-square tests (p < 0.05); analyses were performed with SPSS version 22.0. RESULTS: The top health topics chosen were gynecological cancer (66.0%), joint/muscle aches and pain (64.4%), bone health (63.2%), breast screening (55.9%), and heart health (55.3%). Adjusted results from the logistic regression model found that the odds of choosing the topics gynecological cancer, cervical screening, and complementary and alternative medicine for menopausal symptoms were significantly lower in age groups 55-59, 60-64 and 65-69 years compared to age group 45-49 years. Both Malay and Indian women were less likely to report bone health as important (odds ratio = 0.59, 95% confidence interval = 0.41-0.86) and (odds ratio = 0.64, 95% confidence interval = 0.42-0.98), respectively. Written leaflets were chosen by the majority (84.7%). CONCLUSION: This study of over 1000 midlife Asian women found that holistic health information is desired and requires tailoring by age, not ethnicity. Written information was preferred over support groups. These findings will guide clinical health services in delivering patient-centered information resources for midlife women.

Comparison of two different optical coherence tomography angiography devices in detecting healthy versus glaucomatous eyes - an observational cross-sectional study.

BACKGROUND: To understand the differences between two different optical coherence tomography angiography (OCTA) devices in detecting glaucomatous from healthy eyes by comparing their vascular parameters, diagnostic accuracy and test-retest reliability. METHODS: A cross-sectional observational study was performed on healthy and glaucoma subjects, on whom two sets of OCTA images of optic disc and macula were acquired using both AngioVue (Optovue, USA) and Swept Source (Topcon, Japan) OCTA devices during one visit. A novel in-house software was used to calculate the vessel densities. Diagnostic accuracy of the machines in differentiating healthy versus glaucomatous eyes was determined using area under the receiver operating characteristic curve (AUROC) and test-retest repeatability of the machines was also evaluated. RESULTS: A total of 80 healthy and 38 glaucomatous eyes were evaluated. Glaucomatous eyes had reduced mean vessel density compared to healthy controls in all segmented layers of the optic disc and macula using AngioVue (p ≤ 0.001). However, glaucomatous eyes had higher mean vessel density on optic disc scans using Swept Source, with lack of statistically significant difference between healthy and glaucomatous eyes. The AUROC showed better diagnostic accuracy of AngioVue (0.761-1.000) compared to Swept Source (0.113-0.644). The test-retest reliability indices were generally better using AngioVue than Swept Source. CONCLUSIONS: AngioVue showed better diagnostic capability and test-retest reliability compared to Swept Source. Further studies need to be undertaken to evaluate if there is any significant difference between the various machines in diagnosing and monitoring glaucoma.

Broadband signal response of thermo-acoustic devices and its applications.

Thermo-acoustic (TA) transducers are generation of sound speakers without any mechanical vibration system which exhibit an extremely wide frequency response range. In this paper, acoustic field responses to broadband input signals applied to both free-standing and nano-thinfilm-substrate thermo-acoustic devices are developed theoretically by using the Fourier transformation. A series of signals, including single-frequency signal, square root signal, periodic triangle wave signal, and periodic rectangular pulse signal, are applied to these TA devices in simulations and the acoustic pressure responses are investigated. The reproducibility of input signals is predicted. The single frequency results show good agreement with previously published experimental results. Alternative methods for reproducing the original signals with small distortion and low power consumption are introduced. The excellent performance of the TA devices on broadband signal responses will provide a design approach for sound parametric array and underwater communication equipment.

Characteristics of 1-day postoperative mortality: a comparison with 2- to 7-day postoperative mortality.

BACKGROUND: The purpose of this study was to determine causes and characteristics of early postoperative mortality focusing on postoperative day 1 (POD 1). METHODS: We reviewed the electronic medical records of patients who died within 7 days after surgery under anesthesia at a tertiary university hospital from January 2004 to December 2014. Postoperative mortalities were divided into POD 1 group and POD 7 group, which included death that occurred from days 2 to 7 after surgery. Characteristics of POD 1 group were compared with those of POD 7 group. RESULTS: The mortality rates of POD 1 and POD 7 groups were 3.6 and 7.8 per 10,000 anesthesia, respectively. The incidence of POD 1 mortality is higher than any other day of the week of surgery. The incidences of massive transfusion, intraoperative cardiac arrest, and intraoperative use of epinephrine were higher in POD 1 group than in POD 7 group. In adults, the proportion of emergency operations was higher in POD 1 group than in POD 7 group. The leading cause of death in POD 1 group was hypovolemic and cardiogenic shock, whereas that in POD 7 group was distributive shock. Human factor-related mortality was more frequent in POD 1 group (15.3%) compared with POD 7 group (6.1%). CONCLUSIONS: The characteristics of POD 1 mortality were different from those of POD 2-7 mortality. A large proportion of early postoperative deaths were due to POD 1 mortality. Human factor-related causes were more associated with POD 1 mortality, indicating much room for improvement.

The use of a nasogastric tube to facilitate nasotracheal intubation: a randomised controlled trial.

During nasotracheal intubation, the tracheal tube passes through either the upper or lower pathway in the nasal cavity, and it has been reported to be safer that the tracheal tube passes though the lower pathway, just below the inferior turbinate. We evaluated the use of a nasogastric tube as a guide to facilitate tracheal tube passage through the lower pathway, compared with the 'conventional' technique (blind insertion of the tracheal tube into the nasal cavity). A total of 60 adult patients undergoing oral and maxillofacial surgery were included in the study. In 20 out of 30 patients (66.7%) with the nasogastric tube-guided technique, the tracheal tube passed through the lower pathway, compared with 8 out of 30 patients (26.7%) with the 'conventional' technique (p = 0.004). Use of the nasogastric tube-guided technique reduced the incidence and severity of epistaxis (p = 0.027), improved navigability (p = 0.034) and required fewer manipulations (p = 0.001) than the 'conventional' technique.

Sustainable deforestation evaluation model and system dynamics analysis.

The current study used the improved fuzzy analytic hierarchy process to construct a sustainable deforestation development evaluation system and evaluation model, which has refined a diversified system to evaluate the theory of sustainable deforestation development. Leveraging the visual image of the system dynamics causal and power flow diagram, we illustrated here that sustainable forestry development is a complex system that encompasses the interaction and dynamic development of ecology, economy, and society and has reflected the time dynamic effect of sustainable forestry development from the three combined effects. We compared experimental programs to prove the direct and indirect impacts of the ecological, economic, and social effects of the corresponding deforest techniques and fully reflected the importance of developing scientific and rational ecological harvesting and transportation technologies. Experimental and theoretical results illustrated that light cableway skidding is an ecoskidding method that is beneficial for the sustainable development of resources, the environment, the economy, and society and forecasted the broad potential applications of light cableway skidding in timber production technology. Furthermore, we discussed the sustainable development countermeasures of forest ecosystems from the aspects of causality, interaction, and harmony.

Polyhydramnios associated with rare genetic syndromes: two case reports.

BACKGROUND: We present two genetic causes of polyhydramnios that were challenging to diagnose due to their rarity and complexity. In view of the severe implications, we wish to highlight these rare genetic conditions when obstetricians consider differential diagnoses of polyhydramnios in the third trimester. CASE PRESENTATION: Patient 1 is a 34-year-old Asian woman who was diagnosed with polyhydramnios at 28 weeks' gestation. First trimester testing, fetal anomaly scan, and intrauterine infection screen were normal. Subsequent antenatal ultrasound scans revealed macroglossia, raising the suspicion for Beckwith-Wiedemann syndrome. Chromosomal microarray analysis revealed a female profile with no pathological copy number variants. The patient underwent amnioreduction twice in the pregnancy. The patient presented in preterm labor at 34 weeks' gestation but elected for an emergency caesarean section. Postnatally, the baby was noted to have a bell-shaped thorax, coat hanger ribs, hypotonia, abdominal distension, and facial dysmorphisms suggestive of Kagami-Ogata syndrome. Patient 2 is a 30-year-old Asian woman who was diagnosed with polyhydramnios at 30 weeks' gestation. She had a high-risk first trimester screen but declined invasive testing; non-invasive prenatal testing was low risk. Ultrasound examination revealed a macrosomic fetus with grade 1 echogenic bowels but no other abnormalities. Intrauterine infection screen was negative, and there was no sonographic evidence of fetal anemia. She had spontaneous rupture of membranes at 37 + 3 weeks but subsequently delivered by caesarean section in view of pathological cardiotocography. The baby was noted to have inspiratory stridor, hypotonia, low-set ears, and bilateral toe polysyndactyly. Further genetic testing revealed a female profile with a pathogenic variant of the GLI3 gene, confirming a diagnosis of Greig cephalopolysyndactyly syndrome. CONCLUSION: These cases illustrate the importance of considering rare genetic causes of polyhydramnios in the differential diagnosis, particularly when fetal anomalies are not apparent at the 20-week structural scan. We would like to raise awareness for these rare conditions, as a high index of suspicion enables appropriate counseling, prenatal testing, and timely referral to pediatricians and geneticists. Early identification and diagnosis allow planning of perinatal care and birth in a tertiary center managed by a multidisciplinary team.

Prediction of fluid responsiveness in mechanically ventilated children undergoing neurosurgery.

BACKGROUND: The purpose of this study was to evaluate the clinical usefulness of static and dynamic variables for the prediction of fluid responsiveness in children under general anaesthesia. METHODS: Thirty-three mechanically ventilated children received 10 ml kg(-1) colloid for 10 min while stable during surgery. Arterial pressure, heart rate, central venous pressure (CVP), and pleth variability index (PVI), in addition to variation in systolic pressure, pulse pressure (including Δdown and Δup), respiratory aortic blood flow velocity (ΔVpeak), and inferior vena cava diameter were measured before and after volume expansion. Patients were classified as responders to fluid loading if their stroke volume index (SVI) increased by at least 10%. RESULTS: There were 15 volume responders and 18 non-responders. Of the variables examined, ΔVpeak (r=0.516, P=0.004) and PVI (r=0.49, P=0.004) before volume expansion were significantly correlated with changes in SVI. The receiver-operating characteristic (ROC) curve analysis showed that PVI and ΔVpeak predicted fluid responsiveness. Areas under the ROC curves of PVI and ΔVpeak were statistically larger than that of CVP (P=0.006 and 0.014, respectively). However, those of other variables were similar to that of CVP. CONCLUSIONS: ΔVpeak and PVI can be used to predict fluid responsiveness in mechanically ventilated children under general anaesthesia. The other static and dynamic variables assessed in this study were not found to predict fluid responsiveness significantly in children. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT01364103.

Phononic metastructures with ultrawide low frequency three-dimensional bandgaps as broadband low frequency filter.

Vibration and noise control are among the classical engineering problems that still draw extensive research interest today. Multiple active and passive control techniques to resolve these problems have been reported, however, the challenges remain substantial. The recent surge of research activities on acoustic metamaterials for vibration and noise control are testimony to the fact that acoustic metamaterial is no longer limited to pure theoretical concepts. For vibration and noise control over an ultrawide frequency region, 3-D metastructures emerge as a novel solution tool to resolve this problem. In that context, the present study reports a novel proposal for 3-D monolithic phononic metastructures with the capability to induce low frequency ultrawide three-dimensional bandgaps with relative bandwidth enhancements of 157.6% and 160.1%. The proposed monolithic metastructure designs consist of elastic frame assembly that is connected with the rigid cylindrical masses. Such structural configuration mimics monoatomic mass-spring chain where an elastic spring is connected with a rigid mass. We develop an analytical model based on monoatomic mass-spring chain to determine the acoustic mode frequency responsible for opening the bandgap. The wave dispersion study reveals the presence of ultrawide bandgaps for both types of metastructures. The modal analysis shows distribution of vibration energy in the bandgap opening (global resonant mode) and closing (local resonant mode) bounding edges. We further analyze the band structures and discuss the physical concepts that govern such ultrawide bandgap. Vibration attenuation inside the bandgap frequency range is demonstrated by frequency response studies conducted by two different finite element models. Thanks to additive manufacturing technology, 3-D prototypes are prepared and low amplitude vibration test is performed to validate the numerical findings. Experimental results show the presence of an ultrawide vibration attenuation zone that spreads over a broadband frequency spectrum. The bandgaps reported by the proposed metastructures are scale and material independent. The research methodology, modelling and design strategy presented here may pave the way for the development of novel meta-devices to control vibration and noises over a broadband frequency range.

A gravity-driven sintering method to fabricate geometrically complex compact piezoceramics.

Highly compact and geometrically complex piezoceramics are required by a variety of electromechanical devices owing to their outstanding piezoelectricity, mechanical stability and extended application scenarios. 3D printing is currently the mainstream technology for fabricating geometrically complex piezoceramic components. However, it is hard to print piezoceramics in a curve shape while also keeping its compactness due to restrictions on the ceramic loading and the viscosity of feedstocks. Here, we report a gravity-driven sintering (GDS) process to directly fabricate curved and compact piezoceramics by exploiting gravitational force and high-temperature viscous behavior of sintering ceramic specimens. The sintered lead zirconate titanate (PZT) ceramics possess curve geometries that can be facilely tuned via the initial mechanical boundary design, and exhibit high piezoelectric properties comparable to those of conventional-sintered compact PZT (d33 = 595 pC/N). In contrast to 3D printing technology, our GDS process is suitable for scale-up production and low-cost production of piezoceramics with diverse curved surfaces. Our GDS strategy is an universal and facile route to fabricate curved piezoceramics and other functional ceramics with no compromise of their functionalities.

Edible Bird Nest Protects the Kidney From Gentamicin Induced Acute Tubular Necrosis.

Every year, there are about 13.3 million cases of acute kidney injury (AKI). Although AKI is a preventable and treatable disease, if left untreated, it has high risk of multiple organ failure and progression to end stage kidney disease. Acute tubular necrosis (ATN) has been recognised as one of the major causes of AKI. Till to date, there is no effective supplement or medication in treating or reversing AKI. Most of the treatment strategies involve preventative measure to minimise the occurrence of AKI or to reverse the cause of AKI. Hence one of the primary area of research interests is to explore the potential treatment for AKI. Edible bird nests (EBN) are edible food produce by the swiftlet's saliva, which is rich in sialic acids. Sialic acids are monosaccharides that play a vital role in maintaining the integrity and proper function of the human organs, including kidneys. EBN also contains epidermal growth factor, which is widely believed to have rejuvenation and tissue repairing properties. We initiate this study to study the potential reno-protective effect of edible bird's nests by studying the Wistar rat model of gentamicin-induced AKI. Besides renal profiles, renal histology was also semiquantitatively assessed. In our study, pre-treatment with EBN prevented and ameliorated the gentamicin-induced AKI. To a lesser extent, post-treatment with EBN also protected the kidney from the toxic effect of gentamicin. Our findings are highly indicative that EBN possesses reno-protective properties.

Effect of Edible Bird's Nest Extract on Lipopolysaccharide-Induced Impairment of Learning and Memory in Wistar Rats.

Cognitive disability is a common feature associated with a variety of neurological conditions including Alzheimer's Disease (AD), Parkinson's Disease (PD), brain injury, and stroke. Emerging evidence has demonstrated that neuroinflammation plays an important role in the development of cognitive impairment. Current available therapies are relatively ineffective in treating or preventing cognitive disabilities, thus representing an important, unfulfilled medical need. Hence, developing potential treatment is one of the major areas of research interest. Edible bird's nests (EBN) are nests formed by swiftlet's saliva containing sialic acid, which is believed to improve brain function. This present study was embarked upon to evaluate the learning and memory enhancing potential effect of EBN by using Morris water maze test in a Wistar rat model of LPS-induced neuroinflammation. LPS elicited cognitive impairment in the rats by significantly increasing the escape latency while decreasing the number of entries in the probe trial, which are coupled with increased production of proinflammatory cytokines (TNF-α, IL-1ß, and IL-6) and oxidative markers (ROS and TBARS) in the hippocampus. Treatment with EBN (125 mg/kg, 250 mg/kg, and 500 mg/kg; p.o.) effectively reversed the effect of LPS on escape latency and probe trial and, in addition, inhibited the LPS-induced upregulation of proinflammatory cytokines and oxidative markers. These findings are suggestive that there is existence of neuroprotective effect contained inside the edible bird's nest.

Experimental Infection of Goats with a Newly Isolated Strain of Akabane Virus that Causes Encephalomyelitis.

In 2010, there was a large-scale outbreak of bovine encephalomyelitis in Korea, and 15 new strains of Akabane virus (AKAV) were isolated. To identify the pathogenicity of one of these strains, we infected adult goats with AKAV-7 via different routes. Twenty-five female goats were used in this study and were divided into five groups: intracerebral (IC) and intrasubarachnoid (IS) viral inoculation (n = 8 each), intravenous (IV) inoculation (n = 4), and vaccinated before IV inoculation (n = 4), in addition to a negative control animal. All animals inoculated with AKAV-7 had AKAV-neutralizing antibodies at 6-8 days post infection (dpi). During the experimental period, infected animals showed no clinical signs. In the IC group, 5/8 goats had non-suppurative encephalomyelitis affecting the cerebrum. Virus S RNA segments were detected in nearly all areas of the brain. In the IS group, 3/8 goats had encephalomyelitis affecting the cerebrum, cerebellum and spinal cord. At 7 and 21 dpi, virus S RNA segments were found mostly in the spinal cord, especially around the area of injection (L5-L6). Antibody titres in the serum of the vaccinated group had an early onset and slightly increased titre compared with the IV group. Histopathologically, there were no obvious lesions in the central nervous tissues in the vaccinated group, while one of four goats in the IV group showed encephalomyelitis in the parietal lobe of the cerebrum. The newly isolated AKAV-7 can cause encephalomyelitis in goats after experimental injection. The attenuated AKAV vaccine currently used in Korea may provide partial protective immunity against AKAV-7 infection, but the real effect of the vaccine requires further investigation in goats.

Triazolium cyclodextrin click cluster-resin conjugate: an enrichment material for phosphatidylinositol (3,4,5)-triphosphate.

UltraLink was functionalized with a triazolium cyclodextrin click cluster (CCC) which provides a well-oriented, multivalent, positively charged binding site for PtdIns(3,4,5)P3. MALDI TOF MS and LC ESI MS/MS MRM analysis of spiked PtdIns(3,4,5)P3 in lipid extract suggest that triazolium CCC-UltraLink conjugate can be used as an enrichment material for PtdIns(3,4,5)P3.

Fear and distress disorders as predictors of heart disease: A temporal perspective.

OBJECTIVE: Few studies have been able to contrast associations of anxiety and depression with heart disease. These disorders can be grouped in fear and distress disorders. Aim of this study was to study the association between fear and distress disorders with subsequent heart disease, taking into account the temporal order of disorders. METHODS: Twenty household surveys were conducted in 18 countries (n=53791; person years=2,212,430). The Composite International Diagnostic Interview assessed lifetime prevalence and age at onset of disorders, and respondents were categorized into categories based on the presence and timing of fear and distress disorders. Heart disease was indicated by self-report of physician-diagnosed heart disease or self-report of heart attack, together with year of onset. Survival analyses estimated associations between disorder categories and heart disease. RESULTS: Most respondents with fear or distress disorders had either pure distress or pure fear (8.5% and 7.7% of total sample), while fear preceded distress in the large majority of respondents with comorbid fear and distress (3.8% of total sample). Compared to the "no fear or distress disorder" category, respondents with pure fear disorder had the highest odds of subsequent heart disease (OR:1.8; 95%CI:1.5-2.2; p<0.001) and compared to respondents with pure distress disorder, these respondents were at a significantly increased risk of heart disease (OR:1.3; 95%CI:1.0-1.6; p=0.020). CONCLUSION: This novel analytic approach indicates that the risk of subsequent self-reported heart disease associated with pure fear disorder is significantly larger than the risk associated with distress disorder. These results should be confirmed in prospective studies using objective measures of heart disease.

An intelligent tutoring system for trauma management (Trauma-Teach): a preliminary report.

Trauma-Teach is an interactive software for tutoring surgical trainees on medical trauma management procedures. Users of the system interact with a virtual patient suffering from trauma injuries. The task of the user is to stabilise the virtual patient, discover the underlying injuries and decide on an appropriate management plan. Artificial intelligence techniques are used to simulate the patient's pulmonary and cardiovascular systems in real time, determine the responses and results of treatments and diagnostics accordingly, model the patient deterioration if wrong actions are taken, and give a measure of reality to the system by selecting actual trauma cases from the hospital's database.

Efficacy of the APACHE II score at ICU discharge in predicting post-ICU mortality and ICU readmission in critically ill surgical patients.

In this study, we evaluated the efficacy of the discharge Acute Physiology and Chronic Health Evaluation (APACHE) II score in predicting post-intensive care unit (ICU) mortality and ICU readmission during the same hospitalisation in a surgical ICU. Of 1190 patients who were admitted to the ICU and stayed >48 hours between October 2007 and March 2010, 23 (1.9%) died and 86 (7.2%) were readmitted after initial ICU discharge, with 26 (3.0%) admitted within 48 hours. The area under the receiver operating characteristics curve of the discharge and admission APACHE II scores in predicting in-hospital mortality was 0.631 (95% confidence interval [CI] 0.603 to 0.658) and 0.669 (95% CI 0.642 to 0.696), respectively (P=0.510). The area under the receiver operating characteristics curve of discharge and admission APACHE II scores for predicting all forms of readmission was 0.606 (95% CI 0.578 to 0.634) and 0.574 (95% CI 0.545 to 0.602), respectively (P=0.316). The area under the receiver operating characteristics curve of discharge APACHE II score in predicting early ICU readmissions was, however, higher than that of admission APACHE II score (0.688 [95% CI 0.660 to 0.714] versus 0.505 [95% CI 0.476 to 0.534], P=0.001). The discharge APACHE II score (odds ratio [OR] 1.1, 95% CI 1.01 to 1.22, P=0.024), unplanned ICU readmission (OR 20.0, 95% CI 7.6 to 53.1, P=0.001), eosinopenia at ICU discharge (OR 6.0, 95% CI 1.34 to 26.9, P=0.019), and hospital length-of-stay before ICU admission (OR 1.02, 95% CI 1.01 to 1.03, P=0.021) were significant independent factors in predicting post-ICU mortality. This study suggests that the discharge APACHE II score may be useful in predicting post-ICU mortality and is superior to the admission APACHE II score in predicting early ICU readmission in surgical ICU patients.

Effects of sodium dodecylsulphate, dye concentration and paraprotein on coomassie blue dye-binding assays for protein in urine.

Various Coomassie Blue reagents, containing either increased dye concentration or added sodium dodecylsulphate, were compared with a biuret method for the assay of total protein in urine. When immunoglobulin free light chain protein or immunoglobulin paraprotein were present, results from the Coomassie Blue methods were up to 50% lower than with the biuret method; increased dye concentration did not improve comparability substantially, but the addition of sodium dodecylsulphate reduced the bias to about 20%. When neither free light chain protein nor immunoglobulin paraprotein was present, results from the Coomassie Blue methods were only about 30% lower. The addition of sodium dodecylsulphate reduced this bias to 10%. Correlations between the biuret and the Coomassie Blue method were best when the Coomassie Blue reagent contained 40 mg/L sodium dodecylsulphate (r better than 0.98 in all groups; p less than 0.001).

A method for the separation of delta bilirubin using Cibacron Blue affinity chromatography.

We developed and evaluated a method for the separation of delta bilirubin (B delta) by micro-column affinity chromatography based on Cibacron Blue 3G-A-Agarose. Untreated serum was applied to affinity columns and free non-protein bound bilirubins were eluted with phosphate buffer containing 20 g/l Triton X-100. Retained albumin was eluted using caffeine-benzoate reagent and bilirubin associated with this fraction (B delta) quantitated by the method of Jendrassik and Gróf modified by Doumas et al (Clin Chem 1985;31:1779-1789); results correlated well with the high performance liquid chromatography (HPLC) method (n = 35, y (affinity) = 1.009x (HPLC)-5.49; r = 0.959) described by Lauff et al. (J Chromatography 1981;226:391-402). Two controls analyzed with each batch gave between-batch imprecision less than 4.0% (n = 10; Control 1, mean = 20.05 mumol/l; Control 2, mean = 74.82 mumol/l). Within-batch imprecision was less than 3.3% for both levels. Specimens collected from 25 neonates less than 20 days of age showed a B delta concentration of 1.7 +/- 0.7 mumol/l (mean +/- 1 S.D.) and percent B delta of 2.2 +/- 1.9 (mean total bilirubin +/- 1 S.D. = 118 +/- 79 mumol/l). Although time consuming, this simple and precise method allows the measurement of B delta in laboratories without the need for specialized instruments.