LaMer diagram approach to study the nucleation and growth of Cu2O nanoparticles using supersaturation theory

Uptake to cuprous oxide (Cu₂O) nanoparticle synthesis with various particle sizes and shapes via supersaturation chemistry approach (LaMer model) has been conducted. Ascorbic acid and maltodextrine as reducing agents and polyvinylpyrrolidone (PVP) as a surfactant were utilized for synthesis of Cu₂O nanoparticles in aqueous solution. The narrow particle size range was achieved by controlling the kinetics of nucleation and growth of particles to satisfy LaMer theory. This mean was performed utilizing different reducing agents (ascorbic acid and maltodextrin) and also, changing the reducing agent addition condition. The results showed the reducing agent addition condition, varying the size of Cu₂O nanoparticles from 89 nm to 74 nm for drop-wisely and at-once routes, respectively. The samples were characterized by XRD, SEM, and UV-Vis spectroscopy. The results indicate the shape of as-prepared cuprous oxide nanoparticles have close relationship with thermodynamic and kinetic conditions, and also reducing addition condition.     

Incidence of aflatoxin M1 in human breast milk in Tehran, Iran

This study examined the exposure of infants to aflatoxin M1 (AFM1) and of lactating mothers to aflatoxin B1 (AFB1), using AFM1 in breast milk as a biomarker for exposure to AFB1. An enzyme-linked immunosorbent assay (ELISA) was modified for the analysis of AFM1 in breast milk samples from 160 women in Tehran, Iran. AFM1 was detected in 157 samples by average concentration of 8.2 ± 5.1 ng/kg (range 0.3–26.7 ng/kg).The concentration of AFM1 in one sample was higher than the maximum tolerance limit accepted by European Union and USA (25 ng/kg), but in 55 samples was higher than the maximum concentration recommended by Australia and Switzerland (10 ng/kg).Logistic regression Analysis failed to show significant correlation between AFM1 and gestational age, education, postnatal age, gender, nationality, clinical condition, the number of family member, the number of children, type and amount of dairy consumption, vegetable, fruits, oil and meat. But it was significant relation to the cereal consumption, also to the height at birth.     

The sequence of precipitation in the Al-Mg-Si-Cu alloy AA6111

The preciptation behavior of the aluminum alloy AA6111 in the advanced stages of aging has been studied using differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and high-resolution TEM (HRTEM). The results have demonstrated the formation of various precipitate types and morphologies of quaternaryQ phase andβ (Mg₂Si) families at the peak-aged condition and during overaging at different temperatures. The work has clarified the sequence ofQ phase formation and showed evidence for a new morphology of this phase. The sequence of precipitation in AA6111 is elaborated in light of the new findings.     

Active vibration control of an arbitrary thick smart cylindrical panel with optimally placed piezoelectric sensor/actuator pairs

Active vibration suppression of a simply supported, arbitrarily thick, transversely isotropic circular cylindrical host panel, integrated with spatially distributed piezoelectric actuator and sensor layers, is investigated based on the linear three dimensional exact piezo-elasticity theory. To assist control system design, system identification is conducted by applying a frequency domain subspace approximation method based on N4SID algorithm using the first few structural modes of the system. The state space model is constructed from system identification and used for state estimation and development of control algorithm. The optimal electrode configuration for the collocated piezoelectric actuator–sensor pair is found by applying a genetic optimization procedure based on maximization of a quantifiable objective function considering the controllability, observability and spillover prevention of the identified system. A linear quadratic Gaussian (LQG) optimal controller is subsequently designed and simulated based on the identified model of optimally configured smart structure in order to actively control the system response in both frequency and time domains. The dynamic performance and effectiveness of the optimized vibration control system is demonstrated for two different types of external mechanical excitations (i.e., impulsive load and white noise disturbance). The accuracy of dynamic analysis is established with the aid of a commercial finite element package and the data available in the literature.     

Global ESRD Costs Associated with a Short Daily Hemodialysis Program in the United States

In spite of the growing evidence that daily hemodialysis (DHD) improves clinical outcomes and quality of life, the additional dialysis costs are not currently reimbursed in the United States. Nor have there been reports of the effects of DHD on end-stage renal disease (ESRD) global costs, which would help predict the financial impact of DHD on the ESRD program. Since 1996, 22 patients (20 in-center, 2 home) have switched from conventional thrice-weekly dialysis to short, daily dialysis with six treatments per week. Eighteen patients started for medical indications, and four started for nonmedical reasons. Causes of ESRD were the following: diabetes mellitus (6), hypertension (4), glomerulonephritis (6), hereditary (2), and other (4). Mean age was 56 ± 16 years. Patients had an average of 3.3 major comorbidities. Weekly conventional HD dialysis times were divided into six DHD treatments, each 2.0 ± 0.3 hours. Weekly Kt/V remained unchanged. Twenty-two patients were followed on DHD for 220 patient-months: 7 patients died after 1.8 ± 1.3 months, 2 were transplanted at 4.3 ± 3.2 months, and 2 discontinued DHD at 3.6 ± 4.8 months. Eleven patients remain on DHD at 17.4 ± 8.3 months. Actual costs per extra dialysis session are as follows: $14.30 for supplies and $3.20 for labor for setup/cleanup time (15 minutes at $12.80/hour). Annualized DHD savings are based on comparison of doses of epoetin alpha (Epogen) and blood pressure medication at the start and after 12 months of DHD. Hospitalization rates include all enrolled patients, comparing rates for the 12 months prior to DHD with the first year on DHD, or annualized rates for those on DHD less than one year. Cost assumptions are $9/ 1000 U Epogen, $1/blood pressure pill, and $1200/per day of hospitalization. Extra transportation costs were covered by the patients. No increased access problems were observed. For patients on short DHD longer than 12 months, supply and labor costs increased to $2733/patient/year; however, Epogen use was reduced 55%, and blood pressure medications were reduced 40%. For all patients who switched to DHD, hospitalization rates were reduced 24%. This resulted in a net savings of about $4241/patient/ year after 12 months on DHD. Overall ESRD costs were substantially decreased on DHD. These cost savings must be passed on to providers before DHD becomes more widely available.     

Adaptive Immune Responses in a Multiple Sclerosis Patient with Acute Varicella-Zoster Virus Reactivation during Treatment with Fingolimod

Fingolimod, an oral sphingosine 1-phosphate (S1P) receptor modulator, is approved for the treatment of relapsing forms of multiple sclerosis (MS). The interference with S1P signaling leads to retention particularly of chemokine receptor-7 (CCR7) expressing T cells in lymph nodes. The immunological basis of varicella zoster virus (VZV) infections during fingolimod treatment is unclear. Here, we studied the dynamics of systemic and intrathecal immune responses associated with symptomatic VZV reactivation including cessation of fingolimod and initiation of antiviral therapy. Key features in peripheral blood were an about two-fold increase of VZV-specific IgG at diagnosis of VZV reactivation as compared to the previous months, a relative enrichment of effector CD4+ T cells (36% versus mean 12% in controls), and an accelerated reconstitution of absolute lymphocytes counts including a normalized CD4+/CD8+ ratio and reappearance of CCR7+ T cells. In cerebrospinal fluid (CSF) the lymphocytic pleocytosis and CD4+/CD8+ ratios at diagnosis of reactivation and after nine days of fingolimod discontinuation remained unchanged. During this time CCR7+ T cells were not observed in CSF. Further research into fingolimod-associated VZV reactivation and immune reconstitution is mandatory to prevent morbidity and mortality associated with this potentially life-threatening condition.     

Preparation and Characterization of Nanocrystalline Misch-Metal-Substituted Yttrium Iron Garnet Powder by the Sol–Gel Combustion Process

Nanocrystalline Y_{3− x} MM _x Fe₅O₁₂ powders (MM denotes Misch-metal, x =0.0, 0.25, 0.5, 0.75, and 1.0) were synthesized by a sol–gel combustion method. Magnetic properties and crystalline structures were investigated using X-ray diffraction (XRD), a vibrating sample magnetometer (VSM), and a scanning electron microscope. The XRD patterns showed that the single-phase garnet of Y_{3− x} MM _x Fe₅O₁₂ was formed at x values ≤1.0. The saturation magnetization of powders increased with decreasing MM content and reached the maximum value at Y₃Fe₅O₁₂. The crystallite size of powders calcined at 800°C for 3 h was in the range of 38–53 nm.     

Trash into Treasure: δ‐FAPbI3 Polymorph Stabilized MAPbI3 Perovskite with Power Conversion Efficiency beyond 21%

Effective passivation and stabilization of both the inside and interface of a perovskite layer are crucial for perovskite solar cells (PSCs), in terms of efficiency, reproducibility, and stability. Here, the first formamidinium lead iodide (δ‐FAPbI₃) polymorph passivated and stabilized MAPbI₃ PSCs are reported. This novel MAPbI₃/δ‐FAPbI₃ structure is realized via treating a mixed organic cation MA _x FA_{1‐ x} PbI₃ perovskite film with methylamine (MA) gas. In addition to the morphology healing, MA gas can also induce the formation of δ‐FAPbI₃ phase within the perovskite film. The in situ formed 1D δ‐FAPbI₃ polymorph behaves like an organic scaffold that can passivate the trap state, tunnel contact, and restrict organic‐cation diffusion. As a result, the device efficiency is easily boosted to 21%. Furthermore, the stability of the MAPbI₃/δ‐FAPbI₃ film is also obviously improved. This δ‐FAPbI₃ phase passivation strategy opens up a new direction of perovskite structure modification for further improving stability without sacrificing efficiency.