One pot application of a green chemistry-based finish for cotton fabric, providing hydrophobic, flame retardant, and antimicrobial properties

Fluorinated and formaldehyde-based compounds impart excellent hydrophobicity and flame-retardant properties to cotton fabrics. However, they come with various health and environmental risks. A novel hydrophobic, flame retardant, and antimicrobial finishing agent free from fluorine and formaldehyde was synthesized. The diammonium phosphate octadecyl citrate (DAPOC) was synthesized by using stearic acid (octadecanoic acid), citric acid (propane-1,2,3-tricarboxylic acid), and diammonium hydrogen phosphate. It was grafted onto the cotton fabrics by employing the conventional pad-dry-cure method. The results indicated that this newly developed finish could be chemically bonded to cotton fabrics through C-O-C covalent bonds. The contact angle of the cotton fabric finished with a 12% concentration of the finishing agent reached 151.9°. Additionally, the finished cotton fabrics displayed evident flame-retardant properties. After undergoing 20 laundering cycles, DAPOC maintained strong hydrophobic and flame-retardant characteristics, demonstrating its durability. The chemical structure of DAPOC was verified by nuclear magnetic resonance spectroscopy (1H-NMR). The thermogravimetric analysis confirmed the flame-retardant nature of the treated cotton fabric samples. Scanning electron microscopy (SEM), Energy dispersive X-ray analysis (EDX), and Fourier-transform infrared spectroscopy (FTIR) results demonstrated the successful grafting of the newly created finish onto the cotton fiber. X-ray diffraction (XRD) spectra depicted that the crystalline structure of finished cotton fabric remained mostly unaltered. Furthermore, the finished cotton fabric exhibited commendable antimicrobial properties due to the inclusion of citric acid.

Utilization and Performance Evaluation of Mixed Matrix Membranes for the Treatment of Produced Water: A Review

Produced water (PW) has been generated in a huge amount representing the largest volume waste stream. Membrane technology has found a leading ability in treating PW due to its significant advantages, such as lower cost, easy installation, and being environmentally friendly. Mixed matrix membranes (MMMs) have received significant research interest due to their flexibility, multifunctionality enhances the membrane performance with increasing selectivity, permeability, robustness, mechanical strength, and resistance to fouling. This mini-review paper identifies the utilization of different membranes for treating PW. It also gives a holistic review of different types of MMMs with specific fillers for the application of PW treatment. Lastly, some methods to enhance the performance of mixed matrix membranes have been highlighted. The issues and challenges in membranes are also discussed.

Prediction of single salt rejection in PES/CMS based membranes

This study explains the modeling of synthesized membranes using the Donnan Steric Pore model (DSPM) based on the Extended Nernst Planck Equation (ENP). Conventionally, structural parameters required to predict the performance of the membranes were determined through tedious experimentation, which in this study are found using a new MATLAB technique. A MATLAB program is used to determine the unknown structural parameters such as effective charge density (X_d), effective pore radius (r_p), and effective membrane thickness to porosity ratio (Δx/A_k) by using the single solute rejection and permeation data. It was found that the model predicted the rejection of studied membranes accurately, with the E5C1 membrane exceeding the others (E5, E5C5) for rejection of single and divalent salt's aqueous solutions. The rejection of 100 ppm aqueous solution of NaCl for E5C1 was around 60%, whereas, for an aqueous solution of 100 ppm, CaCl₂ rejection reached up to 80% at 10 bar feed pressure. The trend of salt rejection for all three membranes was found to be in the following order: E5C1 > E5C5 > E5, confirming that their structural parameters-controlled ion transport in these membranes. The structural parameters, such as effective pore radius, effective membrane thickness to porosity ratio, and effective charge density for the best performing membrane, i.e., E5C1, were determined to be 0.5 nm, 16 μm, and -6.04 mol/m^3,respectively. Finally, it can be asserted that this method can be used to predict the real performance of membranes by significantly reducing the number of experiments previously required for the predictive modeling of nanofiltration-type membranes.

Interfacial Tailoring of Polyether Sulfone-Modified Silica Mixed Matrix Membranes for CO2 Separation

In this work, in situ polymerization of modified sol-gel silica in a polyether sulfone matrix is presented to control the interfacial defects in organic-inorganic composite membranes. Polyether sulfone polymer and modified silica are used as organic and inorganic components of mixed matrix membranes (MMM). The membranes were prepared with different loadings (2, 4, 6, and 8 wt.%) of modified and unmodified silica. The synthesized membranes were characterized using Field emission electron scanning microscopy, energy dispersive X-ray, Fourier transform infrared spectroscopy, thermogravimetric analyzer, and differential scanning calorimetry. The performance of the membranes was evaluated using a permeation cell set up at a relatively higher-pressure range (5-30 bar). The membranes appear to display ideal morphology with uniform distribution of particles, defect-free structure, and absence of interfacial defects such as voids and particle accumulations. Additionally, the CO₂/CH₄ selectivity of the membrane increased with the increase in the modified silica content. Further comparison of the performance indicates that PES/modified silica MMMs show a promising feature of commercially attractive membranes. Therefore, tailoring the interfacial morphology of the membrane results in enhanced properties and improved CO₂ separation performance.

Incorporating Carbon Nanotubes in Nanocomposite Mixed-Matrix Membranes for Gas Separation: A Review

Carbon nanotube (CNT) is a prominent material for gas separation due to its inherent smoothness of walls, allowing rapid transport of gases compared to other inorganic fillers. It also possesses high mechanical strength, enabling membranes to operate at high pressure. Although it has superior properties compared to other inorganic fillers, preparation of CNTs into a polymer matrix remains challenging due to the strong van der Waals forces of CNTs, which lead to agglomeration of CNTs. To utilize the full potential of CNTs, proper dispersion of CNTs must be addressed. In this paper, methods to improve the dispersion of CNTs using functionalization methods were discussed. Fabrication techniques for CNT mixed-matrix membrane (MMM) nanocomposites and their impact on gas separation performance were compared. This paper also reviewed the applications and potential of CNT MMMs in gas separation.

Developing understanding of the fate and behaviour of silver in fresh waters and waste waters

The Windermere Humic Aqueous Model (WHAM) is often used for risk assessment of metals; WHAM can be used to estimate the potential bioavailability of dissolved metals, where metals complexed to dissolved organic matter (DOM) are expected to be less toxic than ionic forms. Silver is a potential metal of concern but WHAM has not been rigorously tested against experimental measurements. This study compares WHAM predictions to measured ionic silver during fixed pH (4, 8 or 10) argentometric titrations of DOM from diverse origins. There were almost two orders of magnitude variation in free silver between sources but, within model uncertainty, WHAM captured this variability. This agreement, between measurements and models, suggests that WHAM is an appropriate tool for silver risk assessment in surface receiving waters when DOM is predominantly in the form of humic/fulvic acids. In sewage samples WHAM dramatically underestimated silver binding by approximately 3 orders of magnitude. Simulations with additional specific strong silver binding sulphide-like binding sites could explain Ag binding at low loadings, but not at higher loadings. This suggests the presence of additional intermediate strength binding sites. These additional ligands would represent components of the raw sewage largely absent in natural waters unimpacted by sewage effluents. A revised empirical model was proposed to account for these sewage-specific binding sites. Further, it is suspected that as sewage organic matter is degraded, either by natural attenuation or by engineered treatment, that sewage organic matter will degrade to a form more readily modelled by WHAM; i.e., humic-like substances. These ageing experiments were performed starting from raw sewage, and the material did in fact become more humic-like, but even after 30 days of aerobic incubation still showed greater Ag⁺ binding than WHAM predictions. In these incubation experiments it was found that silver (up to 1000 μg/L) had minimal impact on ammonia oxidation kinetics.

Composite amine mixed matrix membranes for high-pressure CO2-CH4 separation: synthesis, characterization and performance evaluation

The key challenge in the synthesis of composite mixed matrix membrane (MMMs) is the incompatible membrane fabrication using porous support in the dry-wet phase inversion technique. The key objective of this research is to synthesize thin composite ternary (amine) mixed matrix membranes on microporous support by incorporating 10 wt% of carbon molecular sieve (CMS) and 5-15 wt% of diethanolamine (DEA) in polyethersulfone (PES) dope solution for the separation of carbon dioxide (CO₂) from methane (CH₄) at high-pressure applications. The developed membranes were evaluated for their morphological structure, thermal and mechanical stabilities, functional groups, as well as for CO₂-CH₄ separation performance at high pressure (10-30 bar). The results showed that the developed membranes have asymmetric structure, and they are mechanically strong at 30 bar. This new class of PES/CMS/DEA composite MMMs exhibited improved gas permeance compared to pure PES composite polymeric membrane. CO₂-CH₄ perm-selectivity enhanced from 8.15 to 16.04 at 15 wt% of DEA at 30 bar pressure. The performance of amine composite MMMs is theoretically predicted using a modified Maxwell model. The predictions were in good agreement with experimental data after applying the optimized values with AARE % = ∼less than 2% and R ² = 0.99.

Synthesis, characterization, and performance analysis of carbon molecular sieve-embedded polyethersulfone mixed-matrix membranes for the removal of dissolved ions

The asymmetric polyethersulfone (PES-15 wt.%) mixed-matrix membranes were prepared by incorporation of carbon molecular sieve (CMS) with varying concentrations (1, 3, and 5 wt.%). Physicochemical characterization of synthesized membranes was carried out using field emission scanning electron microscope, atomic force microscopy, contact angle, thermogravimetric analysis, zeta potential analyzer, porosity, and mean pore sizes. Performance analysis of synthesized mixed-matrix membranes was carried out by varying the operating parameters such as pressure (2-10 bar), feed concentration (100-1,000 mg/L), and cations type (Na⁺ , Ca²⁺ , Mg²⁺ , and Sn²⁺ ). Effect of operating parameters and CMS concentration was investigated on pure water flux (PWF), permeate flux, and rejection of membranes. It was found that mixed-matrix membrane containing 15 wt.% PES with 1 wt.% CMS displayed the superior physicochemical characteristics in terms of hydrophilicity (37.9°), surface charge (-13.8 mV), mean pore diameter (6.04 nm), and thermal properties (T_g  = 218.5°C), and overall performance. E5C1 membrane showed 1.5 times higher PWF (75.5 L m^-2  hr^-1 ) and incremented in rejection for all salts than the nascent membrane. PRACTITIONER POINTS: Carbon molecular sieve-embedded mixed-matrix membranes were synthesized by phase inversion method. The resultant membranes experienced improved hydrophilicity, roughness, surface charge, porosity, and mean pore diameter with 1 wt.% CMS loading. The pure water flux was improved from 55.77 to 75.05 L m^-2  hr^-1 when 1 wt.% CMS was added in pure PES. The observed rejection of a mixed-matrix membrane with 1 wt.% CMS was the maximum for all salts.

Surface modification in inorganic filler of mixed matrix membrane for enhancing the gas separation performance

The development of mixed matrix membrane (MMM) in gas separation process has drawn great attention due to its promising properties. MMM consists of a polymer as the matrix phase, whereas the inorganic filler serves as the dispersed phase. However, poor contact between these two phases often results in unselective gas flow and becomes one of the major issues in the MMM development. Currently, various modification techniques of the inorganic filler to improve the compatibility between the polymers and the particles have been reported. Because of this modification, the CO

Effect of fixed carbon molecular sieve (CMS) loading and various di-ethanolamine (DEA) concentrations on the performance of a mixed matrix membrane for CO2/CH4 separation

Polyethersulfone (PES) as a polymer along with carbon molecular sieves (CMS) as an inorganic filler and di-ethanolamine (DEA) as the third component were used to fabricate amine mixed matrix membranes (A3Ms).

Magnetothermoelectric transport in modulated and unmodulated graphene

We draw motivation from recent experimental studies and present a comprehensive study of magnetothermoelectric transport in a graphene monolayer within the linear response regime. We employ the modified Kubo formalism developed for thermal transport in a magnetic field. Thermopower as well as thermal conductivity as a function of the gate voltage of a graphene monolayer in the presence of a magnetic field perpendicular to the graphene plane is determined for low magnetic fields (∼1 T) as well as high fields (∼8 T). We include the effects of screened charged impurities on thermal transport. We find good qualitative and quantitative agreement with recent experimental work on the subject. In addition, in order to analyze the effects of modulation, which can be induced by various means, on the thermal transport in graphene, we evaluate the thermal transport coefficients for a graphene monolayer subjected to a periodic electric modulation in a magnetic field. The results are presented as a function of the magnetic field and the gate voltage.

Thermodynamic properties of a weakly modulated graphene monolayer in a magnetic field

Theoretical investigation of thermodynamic properties of an electrically modulated graphene monolayer in the presence of a perpendicular magnetic field B is presented. This work is aimed at determining the modulation-induced effects on the thermodynamic properties of graphene. The results obtained are compared with those of conventional two-dimensional electron gas (2DEG) systems realized in semiconductor heterostructures. The one-dimensional periodic potential, due to electric modulation lifts the degeneracy of the Landau levels and converts them into bands whose width oscillates as a function of B. We find commensurability (Weiss) oscillations for small values of B and de Haas-van Alphen (dHvA)-type oscillations at larger values of B. We find that the modulation-induced effects on the thermodynamic properties are enhanced and less damped with temperature in graphene compared with conventional 2DEG systems. Furthermore, we have derived analytic asymptotic expressions which allow us to determine the critical temperature and critical magnetic field for the damping of magnetic oscillations in the thermodynamic quantities considered here.

Microdeletion/duplication at 15q13.2q13.3 among individuals with features of autism and other neuropsychiatric disorders

BACKGROUND

Segmental duplications at breakpoints (BP4-BP5) of chromosome 15q13.2q13.3 mediate a recurrent genomic imbalance syndrome associated with mental retardation, epilepsy, and/or electroencephalogram (EEG) abnormalities.

PATIENTS

DNA samples from 1445 unrelated patients submitted consecutively for clinical array comparative genomic hybridisation (CGH) testing at Children's Hospital Boston and DNA samples from 1441 individuals with autism from 751 families in the Autism Genetic Resource Exchange (AGRE) repository.

RESULTS

We report the clinical features of five patients with a BP4-BP5 deletion, three with a BP4-BP5 duplication, and two with an overlapping but smaller duplication identified by whole genome high resolution oligonucleotide array CGH. These BP4-BP5 deletion cases exhibit minor dysmorphic features, significant expressive language deficits, and a spectrum of neuropsychiatric impairments that include autism spectrum disorder, attention deficit hyperactivity disorder, anxiety disorder, and mood disorder. Cognitive impairment varied from moderate mental retardation to normal IQ with learning disability. BP4-BP5 covers approximately 1.5 Mb (chr15:28.719-30.298 Mb) and includes six reference genes and 1 miRNA gene, while the smaller duplications cover approximately 500 kb (chr15:28.902-29.404 Mb) and contain three reference genes and one miRNA gene. The BP4-BP5 deletion and duplication events span CHRNA7, a candidate gene for seizures. However, none of these individuals reported here have epilepsy, although two have an abnormal EEG.

CONCLUSIONS

The phenotype of chromosome 15q13.2q13.3 BP4-BP5 microdeletion/duplication syndrome may include features of autism spectrum disorder, a variety of neuropsychiatric disorders, and cognitive impairment. Recognition of this broader phenotype has implications for clinical diagnostic testing and efforts to understand the underlying aetiology of this syndrome.

The Currarino syndrome--hereditary transmitted syndrome of anorectal, sacral and presacral anomalies. Case report and review of the literature

The Currarino triad is a hereditary transmitted syndrome, originally defined by Currarino as ASP-association, consisting of an anorectal malformation, a sacral bony defect and a presacral mass. In most cases autosomal dominant transmission is suggested. In family members one or two features of the syndrome may be missing, indicating an incomplete form of this complex. We describe two unrelated girls at the age of 8 and 9 months respectively with ASP-association. Family screening in both patients showed 8 additional cases with a complete or incomplete Currarino triad, four of them being asymptomatic. A review of the literature up to 1991 revealed 48 patients with ASP-association. In more than 80% of cases, this complex is diagnosed in the first decade, whereas incomplete Currarino syndrome is diagnosed predominantly in adults. Most frequently the presacral mass in ASP-association was reported to be an anterior meningocele (47%) and a benign teratoma (40%). The number of patients with Currarino syndrome has been underestimated so far. We recommend anorectal examination, pelvic ultrasound and pelvic x-rays in all patients with a history of chronic constipation since early childhood. Positive findings should lead to further investigations such as barium enema, MRI, myelography and family screening. Close cooperation between pediatric surgeons and neurosurgeons is required to ensure adequate surgical treatment, considering both the risk of malignant degeneration as well as the risk of intraoperative nerve damage. Thus, radical excisional surgery is not obligatory in every case of Currarino syndrome.

The value of sonography in the detection of osteomyelitis

PURPOSE

A retrospective study was carried out in order to determine the role of sonography in establishing the diagnosis in extremity osteomyelitis.

MATERIALS AND METHODS

The imaging documents of 24 infants and children aged from 2 weeks to 13 years with osteomyelitis (acute 21, chronic 3) were reviewed. Sonograms and conventional radiographs were available in all patients. Additional skeletal scintigraphy had been performed in 13 patients and MRI in only 3. Special emphasis was put on the different ultrasound findings and their onset in the course of disease.

RESULTS

Intra-articular fluid collections (in 15 cases) and/or subperiosteal abscess formation (in 12) were the most frequent early sonographic findings, and preceded any radiographic changes by several days in 11 of these cases. Together with positive clinical signs of inflammation, they were usually sufficient to establish the correct diagnosis. In selected cases, fluid or abscess puncture for immediate microscopic and later bacteriological studies was carried out under sonographic control. In addition, sonography was also able to detect superficial cortical erosion and even an intramedullary focus in a very young patient.

CONCLUSION

Ultrasonography is a very helpful tool for establishing the correct diagnosis in osteomyelitis and reducing the frequency of additional imaging studies.

[Ultrasound of extremity lesions caused by birth trauma]

With regard to injuries of the extremities caused by birth trauma, ultrasound allows simultaneous direct evaluation of the surface of osseous elements and of cartilaginous and soft-tissue structures as well. Thus, not only fractures, but also concomitant articular fluid collections, respectively haematomas and/or dislocation of an epiphysis are demonstrated in their initial extent and in their course of healing. Additionally, closed repositions, for instance of a displaced epiphysis, can be exactly monitored by ultrasound. A reduced number of roentgenograms as well as renunciation of other imaging modalities are the consequence. Own experiences in 4 patients with birth trauma to the humerus confirm the high validity of ultrasound in this area as well.

US-guided hydrostatic reduction of intussusception in children

Over a period of 3 3/4 years, hydrostatic reduction of ileocolic intussusception was performed under sonographic guidance in 47 cases (a total of 41 consecutive patients). The enema consisted of a mixture of isotonic electrolyte solution and water-soluble contrast medium (9:1 ratio) and was given at a hydrostatic pressure of 80-100 cm water. Reduction was successful in 83% of cases (n = 39). Even initially remaining ileo-ileal intussusception could finally be reduced in two cases. No complications were observed. Since, in comparison with other conservative methods of reduction, the success rate was not substantially worse (versus that of pneumatic reduction) or was even higher (versus that of barium enema reduction), the method described can be recommended for wider use because of the substantial reduction in radiation exposure.

Hyperechoic lesions in the basal ganglia: an incidental sonographic finding in neonates and infants

Cerebral ultrasound (US) imaging was performed as a screening procedure in approximately 3,600 neonates and infants over a period of 18 months. Hyperechoic lesions in the basal ganglia and thalamic region were detected incidentally in 15 of these patients. Clinical diagnoses included cytomegalovirus infection, asphyxia, rotavirus infection, prematurity, amniotic infection, dysmorphic stigmata, hyperbilirubinemia, congenital heart disease, and diabetic fetopathia. Lesions showed a single punctate (n = 5), multiple punctate (n = 8), or stripe-like pattern (n = 2), with no disease-specific distribution. Computed tomography performed in two of the 15 patients was normal. Lesions resolved within four to seven months in four of eleven cases who had follow-up studies, whereas echogenicities persisted in the remaining seven patients over a period of observation ranging between one to 15 months. Our results indicate that hyperechoic lesions in the basal ganglia and thalamic region may be associated with congenital infections and asphyxia, but could indicate some other unknown pathology. No correlation was found between the morphology of foci and both clinical diagnosis and results of follow-up studies.

Choroid plexus cysts: a normal finding on ultrasound

Within a period of 2.5 years, cystic structures in the choroid plexus were encountered at cerebral sonography in 70 neonates and babies (45 male, 25 female; 18 premature babies). Their prevalence in patients examined during the first 4 weeks of life (n = 55) was 3%. The size of the cysts ranged from 1-4 and, rarely, up to 7 mm. They were mostly solitary and unilateral. Follow-up sonograms over periods up to 13 months showed that most of the cysts persisted unchanged. A few disappeared (n = 7), while distinct increase in size was observed in 1 case. Since no additional sonographic changes were observed and none of the patients displayed any neurological abnormalities and no association existed with any other, particularly chromosomal, disease, such plexus cysts are postulated to represent a normal sonographic finding and do not require follow-up.

[Deterioration of clinical findings in hip joint follow-ups in neonatal screening]

6 per cent out of 4290 hips checked by neonatal ultrasound screening could be reexamined later on. 7 of 200 hips (i.e. 4 per cent), primarily categorized as type IIa, showed an unexpected severe deterioration to type D (n = 3) or even to type IIIa (n = 4) after a mean-time of 9 weeks. Additional 5 cases with similar unfavourable courses from IIa to IIc, D or IIIa, and even 3 initially normal hips, changing to type IIa, were seen in another screening material (not yet systematically analyzed). Reasons for possible initial misinterpretation (purely visual evaluation in most cases, uncertainties in measuring suboptimal sonographic cuts, deficiencies in technical equipment and documentation), equivocal classification of border-line sonograms as well as possible influence of additional risk factors are discussed. Routine sonographic re-examinations after 6 (to 12) weeks are recommended as obligatory for all hips.