Green and facile synthesis of water-soluble carbon dots from ethanolic shallot extract for chromium ion sensing in milk,fruit juices,and wastewater samples

Self-functionalized carbon dots (CDs) were prepared from ethanolic shallot extract to obtain a total phenolic precursor. The total phenolic extract was then heated at 180 °C for four hours in an autoclave. Only 1 mg L⁻¹ of CDs had high fluorescence emission at 430 nm after excitation at 340 nm and manifested a high selectivity for Cr(vi) ions. The inter- and intra-day emission stability, pH, ionic strength, solvent effect, Stern–Volmer constant, incubation time, speciation of Cr(iii) and Cr(vi) ions, and ion selectivity of the as-prepared CDs were investigated in detail. The proposed method was validated in 20–100 μM linearity with y = 2.2346x as the set-zero intercept linear equation, 0.9981 as the correlation coefficient, 3.5 μM as the limit of detection (LOD), 11.7 μM as the limit of quantification (LOQ), and 2.78% and 5.29% as the intra-day and inter-day relative standard deviations (RSD), respectively. The recovery of drinking water, milk, soymilk, fruit juices (apple and coconut), tap water, and chromium-coated industrial waste water by the investigated Cr sensor was found to be 78.58–119.69%. Therefore, the proposed Cr(vi) sensor had superior advantages of sensitivity, selectivity, rapidity, and reproducibility.

Self-functionalized carbon dots (CDs) were prepared from ethanolic shallot extract to obtain a total phenolic precursor.     

Development of a Neck Pain Risk Score for Predicting Nonspecific Neck Pain With Disability in Office Workers: A 1-Year Prospective Cohort Study

Objective

The purpose of this study was to develop a neck pain risk score for office workers (NROW) to identify office workers at risk for developing nonspecific neck pain with disability.

Methods

A 1-year prospective cohort study of 559 healthy office workers was conducted. At baseline, risk factors were assessed using questionnaires and standardized physical examination. The incidence of neck pain was collected every month thereafter. Disability level was evaluated using the neck disability index. Logistic regression was used to select significant factors to build a risk score. The coefficients from the logistic regression model were transformed into the components of a risk score.

Results

Among 535 (96%) participants who were followed up for 1 year, 23% reported incident neck pain with disability (≥ 5). After adjusting for confounders, the onset of neck pain with disability was significantly associated with history of neck pain, chair adjustability, and perceived muscular tension. Thus, the NROW comprises 3 questions about history of neck pain, chair adjustability, and perceived muscular tension. The NROW had scores ranging from 0 to 4. A cut-off score of at least 2 had a sensitivity of 82% and specificity of 48%. The positive and negative predictive values were 29% and 91%, respectively. The area under the receiver operating characteristic curve was 0.75.

Conclusion

The risk score for nonspecific neck pain with disability in office workers was developed, and it contained 3 items with scores ranging from 0 to 4. This study shows that the score appears to have reasonable sensitivity, specificity, positive predictive value, and negative predictive values for the cut-off point of at least 2.     

GSH-doped GQDs using citric acid rich-lime oil extract for highly selective and sensitive determination and discrimination of Fe3+ and Fe2+ in the presence of H2O2 by a fluorescence “turn-off” sensor

Synthesis and characterization of graphene quantum dots (GQDs) simultaneously doped with 1% glutathione (GSH-GQDs) by pyrolysis using citric acid rich-lime oil extract as a starting material. The excitation wavelength (λ_max = 337 nm) of the obtained GSH-GQD solution is blue shifted from that of bare GQDs (λ_max = 345 nm), with the same emission wavelength (λ_max = 430 nm) indicating differences in the desired N and S matrices decorating the carbon based nanoparticles, without any background effect of both ionic strength and masking agent. For highly Fe³⁺-sensitive detection under optimum conditions, acetate buffer at pH 4.0 in the presence of 50 μM H₂O₂, the linearity range was 1.0–150 μM (R² = 0.9984), giving its calibration curve: y = 34.934x + 169.61. The LOD and LOQ were found to be 0.10 and 0.34 μM, respectively. The method’s precisions expressed in terms of RSDs for repeatability (n = 3 × 3 for intra-day analysis) were 2.03 and 3.17% and for reproducibility (n = 5 × 3 for inter-day analysis) were 3.11 and 4.55% for Fe²⁺ and Fe³⁺, respectively. The recoveries of the method expressed as the mean percentage (n = 3) were found in the ranges of 100.1–104.1 and 98.08–102.7% for Fe²⁺ and Fe³⁺, respectively. The proposed method was then implemented satisfactorily for trace determination of iron speciation in drinking water.

Synthesis and characterization of graphene quantum dots (GQDs) simultaneously doped with 1% glutathione (GSH-GQDs) by pyrolysis using citric acid rich-lime oil extract as a starting material.     

Morelloflavone from Garcinia dulcis as a Novel Biflavonoid Inhibitor of HMG‐CoA Reductase

Morelloflavone, a biflavonoid from Garcinia dulcis previously shown to have hypocholesterolemic activity, was examined for its effect on HMG‐CoA reductase, the rate‐limiting enzyme of the cholesterol biosynthetic pathway. By using the catalytic domain of house mouse HMG‐CoA reductase, morelloflavone was found to inhibit the enzyme activity by competing with HMG‐CoA whereas it was non‐competitive towards NADPH. The inhibition constants (K_i) with respect to HMG‐CoA and NADPH were 80.87 ± 0.06 µm and 103 ± 0.07 µm , respectively. Both flavonoid subunits of this compound, naringenin and luteolin, equally competed with HMG‐CoA with K_i of 83.58 ± 4.37 µm and 83.59 ± 0.94 µm , respectively, and were also non‐competitive with NADPH (K_i of 182 ± 0.67 µm and 188 ± 0.14 µm , respectively). Due to these findings, we suggest that each subunit of morelloflavone would occupy the active site of the enzyme, thereby blocking access of its substrate. The present study thus demonstrates the ability of morelloflavone from G. dulcis to inhibit HMG‐CoA reductase in vitro. As a result, this biflavonoid might serve as a new candidate for the future development of hypocholesterolemic agents. Copyright © 2010 John Wiley & Sons, Ltd.     

Effects of an active break and postural shift intervention on preventing neck and low-back pain among high-risk office workers: a 3-arm cluster-randomized controlled trial

Objective:This study evaluated the effects of the promotion of active breaks and postural shifts on new onset of neck and low-back pain during a 6-month follow-up among high-risk office workers.Methods:A 3-arm cluster-randomized controlled trial with 6-month follow-up was conducted among healthy but high-risk office workers. Participants were recruited from six organizations in Bangkok, Thailand (N=193) and randomly assigned at cluster level into active break intervention (N=47), postural shift intervention (N=46), and control (N=100) groups. Participants in the intervention groups received a custom-designed apparatus to facilitate designated active breaks and postural shifts during work. Participants in the control group received a placebo seat pad. The primary outcome measure was new onset of neck and low-back pain during 6-month follow-up. Analyses were performed using Cox proportional hazard models.Results:One-hundred and eighty-six (96%) predominantly female participants were successfully followed up over six months. New onset of neck pain during the 6-month follow-up occurred in 17%, 17%, and 44% of the participants in the active break, postural shift, and control groups, respectively. For new onset of low-back pain, these percentages were 9%, 7%, and 33%, respectively. Hazard rate (HR) ratios after adjusting for biopsychosocial factors indicated a protective effect of the active break and postural shift interventions for neck pain [HR_adj 0.45, 95% confidence interval (CI) 0.20–0.98 for active break and HR_adj 0.41, 95% CI 0.18–0.94 for postural shift] and low-back pain (HR_adj 0.34, 95% CI 0.12–0.98 for active break and HR_adj 0.19, 95% CI 0.06–0.66 for postural shift).Conclusion:Interventions to increase either active breaks or postural shifts reduced new onset of neck and low-back pain among high-risk office workers.     

Effect of varying initial drink volume on rehydration of horses

Body mass (BM), water intake (WI), and plasma osmolality (P(osm)) and electrolyte concentrations were measured in six 2-year-old Arabian horses provided either 4 l, 8 l, or an unlimited amount of water (UW) for drinking during the initial 5 min of recovery from 45-km of treadmill exercise. After weighing, horses were placed in a stall and further WI between 20 and 60 min of recovery was measured. During exercise, horses lost 3.3+/-0.3%, 3.2+/-0.1%, and 3.3+/-0.2% (P>.05) of BM and P(osm) increased by 7.2+/-0.5, 7.9+/-0.8, and 7.7+/-0.5 mOsm/kg (P>.05) for 4 l, 8 l, and UW, respectively. WI during the first 5 min of recovery was 4.0+/-0.0, 8.0+/-0.0, and 9.0+/-1.3 l and was accompanied by 2.4+/-0.4, 5.8+/-0.9, and 6.1+/-0.7 mOsm/kg decreases (P<.05) in P(osm) for 4 l, 8 l, and UW, respectively. Between 20 and 60 min of recovery, WI was 6.2+/-1.5, 1.2+/-0.6, and 1.0+/-0.7 l (P<.05) for 4 l, 8 l, and UW, respectively. Thus, total WI was 10.2+/-1.5, 9.2+/-0.6, and 10.0+/-1.1 l (P>.05) for 4 l, 8 l, and UW, respectively. After 60 min of recovery, persisting BM loss was 1.3+/-0.5%, 1.1+/-0.2%, and 1.0+/-0.2% (P>.05) for 4 l, 8 l, and UW, respectively and P(osm) had returned to pre-exercise values for all treatments. In conclusion, limiting the volume of water initially provided to horses dehydrated by endurance exercise had no significant effect on total WI during the initial 60 min of recovery; however, persisting BM loss was observed with all treatments. Further, following exercise-induced dehydration, the primary stimulus of thirst was an increase in plasma tonicity rather than hypovolemia.