Abstract
Remazol brilliant blue (RBB) is an anthraquinone anionic dye that has several commercial uses, especially in the textile industries and is well-known for its detrimental impacts on marine ...life and the surrounding ecosystem. Mercury (Hg
2+
) is also one of the most severe hazardous environmental contaminants due to its bioaccumulation through the food chain and high toxicity to the human embryo and fetus. The biosorption potential of
Gelidium corneum
biomass for bioremoval of Hg
2+
and RBB dye simultaneously from binary mixture was assessed. The effects of initial pH, contact time, Hg
2+
, RBB, and biomass concentrations on the biosorption process were investigated in 50 batch experiments using a Face-centered central composite design. The maximum removal percentage of Hg
2+
(98.25%) was achieved in the run no. 14, under optimum experimental conditions: 200 mg/L Hg
2+
, 75 mg/L RBB, pH 5. At 30 °C, 4 g/L algal biomass was used, with a contact time of 180 min. Whereas, the maximum removal percentage of RBB (89.18%) was obtained in the run no. 49 using 200 mg/L Hg
2+
, 100 mg/L RBB, pH 5, 4 g/L algal biomass and 180 min of contact time. FTIR analysis of
Gelidium corneum
biomass surface demonstrated the presence of many functional groups that are important binding sites responsible for Hg
2+
and RBB biosorption. SEM analysis showed apparent morphological alterations including surface shrinkage and the appearance of new shiny adsorbate ion particles on the
Gelidium corneum
biomass surface after the biosorption process. The EDX study reveals an additional optical absorption peak for Hg
2+
, confirming the role of
Gelidium corneum
biomass in Hg
2+
biosorption. In conclusion,
Gelidium corneum
biomass has been shown to be an eco-friendly, sustainable, promising, cost-effective and biodegradable biosorbent to simultaneously biosorb Hg
2+
and RBB dye from aquatic ecosystems.
Summary
A systematic method to design high power and high efficiency mm‐wave fundamental oscillators is presented. By using a linear time variant method, we first obtain the optimum conditions and ...show that these conditions can be significantly different for high power and high efficiency fundamental oscillation. Next, we propose a modified multistage ring oscillator with interstage passive networks to exploit the full capacity of the transistors in terms of output power or efficiency. Analytical expressions are also derived to determine the value of passive elements used in the oscillator. To verify the validity of the method, a 77‐GHz two‐stage (differential) VCO is designed in a 65‐nm CMOS process. Careful electromagnetic and circuit simulations demonstrate that the designed VCO has 2‐GHz tuning range, maximum output power of 10.5 dBm and maximum DC to RF efficiency of 24.1%. The designed VCO shows 54.8% and 108.7% improvement in terms of maximum output power and efficiency compared with a conventional cross‐coupled VCO with the same tuning range.
A systematic method to design high power and high efficiency mm‐wave fundamental oscillators is presented. By using a linear time variant method, we first obtain the optimum conditions and next, we propose a general modified multistage ring oscillator with interstage passive networks to exploit the full capacity of the transistors in terms of output power or efficiency. A 77‐GHz differential VCO is designed to verify the accuracy of proposed design method.
Dentistry practice has become more complex and challenging in the recent years. The clinical decision-making process has experienced many problems due to changing socioeconomic patterns, ...knowledgeable patients, rapid technological advances, and information explosion. The present study reviewed the status of the attitude toward evidence-based dentistry (EBD) among dental students of Iran Universities. The effect of the educational intervention was also assessed.
This systematic review was conducted according to the Preferred Reporting Items for Systematic review and Meta-Analysis checklist. Search strategy was developed by Medical Subject Headings terms and keywords surfing electronic available databases including Medline/PubMed and Google Scholar and local databases such as Scientific Information Database (SID) and Magiran. Two reviewers read the abstracts of all eligible papers and excluded the duplicates. They extracted the information of the full-text of the studies included in the review and assessed the quality by Joanna Briggs Institute critical appraisal checklist.
Ten studies including 8 cross-sectional and 2 interventional studies met the criteria. The assessment of the attitude of 937 dental students from a different region of the country toward EBD showed moderate to acceptable status using 3 different tools. In regard to educational interventions, 2 studies were successful to improve their attitude.
Although the researchers presented good scores on the attitude questionnaires, the quality of the study tools, the eligible criteria for recruiting the participants and the method of evaluating the construct of attitude should be investigated in future studies.
Accurately predicting the probability of live birth and multiple gestations is important for determining a safe number of embryos to transfer after in vitro fertilization. We developed a model that ...can be fit to individual clinic data for predicting singleton, twin, and total live birth rates after human embryo transfer. The predicted and observed rates of singleton and twin deliveries were compared in a tenfold cross-validation study using data from a single clinic. The model presented accounts for patient age, embryo stage (cleavage or blastocyst), type of transfer cycle (fresh or frozen) and uterine/universal factors. The standardized errors for rates of singleton and twin deliveries were normally distributed and the mean errors were not significantly different from zero (all p > 0.05). The live birth rates per embryo varied from as high as 43% for fresh blastocysts in the 35-year-old age group to as low as 1% for frozen cleavage stage embryos in the 43-year-old age group. This quantitative model or a simplified version can be used for clinics to generate and analyze their own data to guide the number of embryos to transfer to limit the risk of multiple gestations.
Summary
In this paper, a reconfigurable receiver front‐end for the frequency range of 800 MHz to 2.5 GHz is presented. The radio frequency front‐end is realized in wideband form with reconfigurable ...baseband filter. The proposed front‐end targets the GSM, WLAN, WCDMA, and GPS standards residing in the aimed frequency range. The necessary specifications for each individual standard have been revisited and recalculated. The interaction of the different standards and their interoperability has been thoroughly investigated and extra specifications derived for the multistandard receiver. The multistandard receiver has been designed, layouted, and simulated in RFCMOS 0.18‐μm process.
The architecture of the proposed front‐end.
To determine the relationship between prior obstetrical history and gestational age at delivery in a twin pregnancy.
Retrospective cohort study using the United States Society for Assisted ...Reproductive Technology Clinic Outcomes Reporting System database.
Clinic-based data.
Patients undergoing in vitro fertilization (IVF) in the United States with live delivery of twins.
None.
The main outcome measures are median gestational age at delivery and rate of preterm delivery (before 37 weeks).
The median gestational age at delivery of IVF-conceived twins was 36.3 (interquartile rate 34.4, 37.6) weeks for nulliparous women, 35.9 (34.0, 37.1) weeks for parous women with a prior preterm birth, and 36.7 (35.1, 37.7) weeks for parous women without a prior preterm birth. The rate of preterm delivery was 61% for nulliparous women, 70% for parous women with a prior preterm birth, and 55% for parous women without a prior preterm birth.
Parous women without a history of preterm delivery had lower rates of preterm delivery in a subsequent twin pregnancy than nulliparous women. Nulliparous women had lower rates of preterm delivery compared with parous women with a history of preterm delivery.
Objective To evaluate the effect of vitrification and two other methods of slow cryopreservation on DNA integrity in expanded and nonexpanded blastocysts. Design Prospective in vitro study. Setting ...Tertiary care academic hospital. Intervention(s) 1) Twenty-two expanded blastocysts (EB) and 17 nonexpanded blastocysts (NEB) vitrified in cryotips; 2) 15 EB and 16 NEB by slow freezing using propanediol; 3) 11 EB and 16 NEB by slow cryopreservation using glycerol; and 4) 14 EB and 13 NEB as fresh control samples. Main Outcome Measure(s) DNA fragmentation by TUNEL and confocal imaging. Result(s) Blastocysts slowly cryopreserved with glycerol showed DNA integrity of 94.76 ± 4.70% and 90.87 ± 6.16% for NEB and EB, respectively. Propanediol cryopreservation showed values of 72.63 ± 13.44% and 56.19 ± 25.49% and vitrification 84.36 ± 8.7%6 and 77.61 ± 16.65%, respectively, for the same groups. The NEB showed less DNA fragmentation than EB in all cryopreservation techniques, but this was significant only with slow freezing using propanediol. Conclusion(s) All cryopreservation techniques induce DNA damage to blastocysts. Damage is maximal with propanediol and minimal with slow freezing using glycerol. The more expanded the blastocyst, the greater is the susceptibility to DNA damage during cryopreservation.
Self-oscillating converters operating in the critical conduction mode are popular in low power applications because of their simplicity and low cost. However, these converters are not suited for ...Power Factor Correction (PFC) because the peak switch current is controlled to regulate the output voltage and does not follow the shape of the line voltage waveform. A new control circuit implementation is proposed for a self-oscillating boost converter to achieve power factor correction. A full featured design example is provided which can be simplified for use in various cost sensitive applications such as electronic lighting, etc. This wide input voltage range self-oscillating PFC prototype achieves less than 10 percent line current distortion in the defined load range (10 W to 40 W).
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