LiNbO3 Thin Films through a Sol-Gel/Spin-Coating Approach Using a Novel Heterobimetallic Lithium-Niobium Precursor.

Lithium niobate is a lead-free material which has attracted considerable attention due to its excellent optical, piezoelectric, and ferroelectric properties. This research is devoted to the synthesis through an innovative sol-gel/spin-coating approach of polycrystalline LiNbO3 films on Si substrates. A novel single-source hetero-bimetallic precursor containing lithium and niobium was synthesized and applied to the sol-gel synthesis. The structural, compositional, and thermal characteristics of the precursor have been tested through attenuated total reflection, X-ray photoelectron spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The LiNbO3 films have been characterized from a structural point of view with combined X-ray diffraction and Raman spectroscopy. Field-emission scanning electron microscopy, energy dispersive X-ray analysis, and X-ray photoelectron spectroscopy have been used to study the morphological and compositional properties of the deposited films.

Stimuli-Responsive Properties of a Zinc(II) Salen-Type Schiff-Base Complex and Vapochromic Detection of Volatile Organic Compounds.

This contribution reports, through a combined thermogravimetric analysis, differential scanning calorimetry, UV-vis, powder X-ray diffraction, and Rietveld refinement analysis, on the stimuli-responsive chromic properties of a substituted Zn(salmal) Schiff-base Lewis acidic complex with unique and distinct thermo- and vapochromic characteristics. The solid complex obtained in air or by evaporation of the solvent from their THF solutions shows a marked thermochromism associated with a phase transition, unusually triggered by the reversible desorption/adsorption of one lattice water molecule. In contrast, the anhydrous solid, achieved from THF solutions of the complex by evaporation of the solvent under anhydrous conditions, behaves very differently as it does not show any absorption of water or thermochromism and exhibits varied vapochromic properties. Detection of volatile organic compounds having Lewis basicity is demonstrated by using the anhydrous solid or the related cast films on glass or paper substrates. In both cases, a marked vapochromism is observed upon exposure to vapors of various volatile species and involves well-defined optical absorptions and naked-eye color changes, also allowing the discrimination of primary aliphatic amines. Vapochromic behavior with the formation of stable, stoichiometric adducts is also demonstrated for both the solid obtained in air and the anhydrous solid or for the related cast films after exposure to vapors of pyridine.

Self-assembled BiFeO3@MIL-101 nanocomposite for antimicrobial applications under natural sunlight.

In this paper, we report on the synthesis of a new hybrid photocatalytic material activated by natural sunlight irradiation. The material consists of multiferroic nanoparticles of bismuth ferrite (BFO) modified through the growth of the Fe-based MIL-101 framework. Material characterization, conducted using various techniques (X-ray diffraction, transmission electron microscopy, FTIR, and X-ray photoelectron spectroscopies), confirmed the growth of the MIL-101 metal-organic framework on the BFO surface. The obtained system possesses the intrinsic photo-degradative properties of BFO nanoparticles significantly enhanced by the presence of MIL-101. The photocatalytic activity of this material was tested in antibacterial experiments conducted under natural sunlight exposure within the nanocomposite concentration range of 100-0.20 µg/ml. The MIL-modified BFO showed a significant decrease in both Minimum Inhibiting Concentration and Minimum Bactericide Concentration values compared to bare nanoparticles. This confirms the photo-activating effect of the MIL-101 modification. In particular, they show an increased antimicrobial activity against the tested Gram-positive species and the ability to begin to inhibit the growth of the four Escherichia coli strains, although at the maximum concentration tested. These results suggest that the new nanocomposite BiFeO3@MOF has been successfully developed and has proven to be an effective antibacterial agent against a wide range of microorganisms and a potential candidate in disinfection processes.

Green Ultrasound-Assisted Synthesis of Rare-Earth-Based MOFs.

Rare-earth (RE)-based metal organic frameworks (MOFs) are quickly gaining popularity as flexible functional materials in a variety of technological fields. These MOFs are useful for more than just conventional uses like gas sensors and catalyst materials; in fact, they also show significant promise in emerging technologies including photovoltaics, optical, and biomedical applications. Using yttrium and europium as ionic host centres and dopants, respectively, and 1,3,5-benzenetricarboxylic acid (H3-BTC) as an organic linker, we describe a simple and green approach for the fabrication of RE-MOFs. Specifically, Y-BTCs and Eu-doped Y-BTCs MOFs have been synthesised in a single step using an eco-friendly method that makes use of ultrasound technology. To establish a correlation between the morphological and structural properties and reaction conditions, a range of distinct reaction periods has been employed for the synthetic processes. Detailed analyses of the synthesised samples through powder X-ray diffraction (PXRD), field emission scanning electron microscopy (FE-SEM), and Fourier-transform infrared spectroscopy (FT-IR) have confirmed the phase formation. Furthermore, thermal analyses such as thermogravimetric analysis (TGA) have been employed to evaluate the thermal stability and structural modifications of the Y-BTC and Eu-doped Y-BTC samples. Finally, the luminescent properties of the synthesised samples doped with Eu3+ have been assessed, providing an evaluation of their characteristics. As a proof of concept, an Eu-doped Y-BTC sample has been applied for the sensing of nitrobenzene as a molecule test of nitro derivatives.

Highly Tunable MOCVD Process of Vanadium Dioxide Thin Films: Relationship between Structural/Morphological Features and Electrodynamic Properties.

The monoclinic structures of vanadium dioxide are widely studied as appealing systems due to a plethora of functional properties in several technological fields. In particular, the possibility to obtain the VO2 material in the form of thin film with a high control of structure and morphology represents a key issue for their use in THz devices and sensors. Herein, a fine control of the crystal habit has been addressed through an in-depth study of the metal organic chemical vapor deposition (MOCVD) synthetic approach. The focus is devoted to the key operative parameters such as deposition temperature inside the reactor in order to stabilize the P21/c or the C2/m monoclinic VO2 structures. Furthermore, the compositional purity, the morphology and the thickness of the VO2 films have been assessed through energy dispersive X-ray (EDX) analyses and field-emission scanning electron microscopy (FE-SEM), respectively. THz time domain spectroscopy is used to validate at very high frequency the functional properties of the as-prepared VO2 films.

Metalorganic Chemical Vapor Deposition Approach to the Synthesis of Perovskite BaCeO3 and BaCe0.8Y0.2O3 Thin Films.

In the present energetic scenario, the development of materials with high potentiality in the technological fields of energy conversion processes, production and storage of hydrogen, are of great interest in the scientific community. In particular, we report for the first time the fabrication of crystalline and homogeneous barium-cerate-based materials in the form of thin films on various substrates. Starting from the ß-diketonate precursor sources Ce(hfa)3diglyme, Ba(hfa)2tetraglyme and Y(hfa)3diglyme (Hhfa = 1,1,1,5,5,5-hexafluoroacetylacetone; diglyme = bis(2-methoxyethyl)ether; tetraglyme = 2,5,8,11,14-pentaoxapentadecane), a metalorganic chemical vapor deposition (MOCVD) approach has been successfully applied to the fabrication of BaCeO3 and doped BaCe0.8Y0.2O3 systems in the form of thin films. Structural, morphological and compositional analyses allowed for an accurate determination of the properties of deposited layers. The present approach represents a simple, easily scalable, and industrially appealing process for the production of compact and homogeneous barium cerate thin films.

A Low Temperature Growth of Cu2O Thin Films as Hole Transporting Material for Perovskite Solar Cells.

Copper oxide thin films have been successfully synthesized through a metal-organic chemical vapor deposition (MOCVD) approach starting from the copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate), Cu(tmhd)2, complex. Operative conditions of fabrication strongly affect both the composition and morphologies of the copper oxide thin films. The deposition temperature has been accurately monitored in order to stabilize and to produce, selectively and reproducibly, the two phases of cuprite Cu2O and/or tenorite CuO. The present approach has the advantages of being industrially appealing, reliable, and fast for the production of thin films over large areas with fine control of both composition and surface uniformity. Moreover, the methylammonium lead iodide (MAPI) active layer has been successfully deposited on the ITO/Cu2O substrate by the Low Vacuum Proximity Space Effusion (LV-PSE) technique. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and atomic force microscopy (AFM) analyses have been used to characterize the deposited films. The optical band gap (Eg), ranging from 1.99 to 2.41 eV, has been determined through UV-vis analysis, while the electrical measurements allowed to establish the p-type conductivity behavior of the deposited Cu2O thin films with resistivities from 31 to 83 Ω cm and carrier concentration in the order of 1.5-2.8 × 1016 cm-3. These results pave the way for potential applications of the present system as a hole transporting layer combined with a perovskite active layer in emergent solar cell technologies.

Journey of a molecule from the solid to the gas phase and vice versa: direct estimation of vapor pressure of alkaline-earth metalorganic precursors for atmospheric pressure vapor phase deposition of fluoride films.

Atmospheric pressure (AP) vapor phase processes such as spatial atomic layer deposition (S-ALD) and AP-metalorganic chemical vapor deposition (AP-MOCVD) are becoming increasingly appealing for their use in a variety of academic and industrial applications. Evaluation of precursor vapour pressures is crucial for their application in AP processes and to this aim the Langmuir equation has been applied as a simple and straightforward method for estimating the vapor pressure and vaporization enthalpy of various metalorganic precursors. Using benzoic acid as a calibration reference, the vapour pressure-temperature curves for several alkaline-earth ß-diketonate fluorinated compounds, with molecular formula "M(hfa)2·L" (with M = Mg, Ca, Sr, Ba; Hhfa = 1,1,1,5,5,5-hexafluoroacetylacetone and L = diglyme, triglyme, and tetraglyme) are derived from their termogravimetric curves. Thus, the enthalpy of vaporization of all complexes has been estimated using the Clausius-Clapeyron equation. As a proof of concept, preliminary results on the use of [Mg(hfa)2·2H2O]·2diglyme and [Ca(hfa)2·diglyme·H2O] or [Ca(hfa)2·triglyme] as precursors for AP-MOCVD deposition of MgF2 and CaF2 in the form of thin films are presented. This approach may be used to easily determine vapor pressures of complexes and thus evaluate "a priori" the suitability of a compound as precursor for AP-MOCVD and/or spatial ALD.

Synthesis of MIL-Modified Fe3O4 Magnetic Nanoparticles for Enhancing Uptake and Efficiency of Temozolomide in Glioblastoma Treatment.

A nanometric hybrid system consisting of a Fe3O4 magnetic nanoparticles modified through the growth of Fe-based Metal-organic frameworks of the MIL (Materials Institute Lavoiser) was developed. The obtained system retains both the nanometer dimensions and the magnetic properties of the Fe3O4 nanoparticles and possesses increased the loading capability due to the highly porous Fe-MIL. It was tested to load, carry and release temozolomide (TMZ) for the treatment of glioblastoma multiforme one of the most aggressive and deadly human cancers. The chemical characterization of the hybrid system was performed through various complementary techniques: X-ray-diffraction, thermogravimetric analysis, FT-IR and X-ray photoelectron spectroscopies. The nanomaterial showed low toxicity and an increased adsorption capacity compared to bare Fe3O4 magnetic nanoparticles (MNPs). It can load about 12 mg/g of TMZ and carry the drug into A172 cells without degradation. Our experimental data confirm that, after 48 h of treatment, the TMZ-loaded hybrid nanoparticles (15 and 20 µg/mL) suppressed human glioblastoma cell viability much more effectively than the free drug. Finally, we found that the internalization of the MIL-modified system is more evident than bare MNPs at all the used concentrations both in the cytoplasm and in the nucleus suggesting that it can be capable of overcoming the blood-brain barrier and targeting brain tumors. In conclusion, these results indicate that this combined nanoparticle represents a highly promising drug delivery system for TMZ targeting into cancer cells.

One-Pot Synthesis of TiO2-rGO Photocatalysts for the Degradation of Groundwater Pollutants.

A non-conventional approach to prepare titanium dioxide-reduced graphene oxide (TiO2-rGO) nanocomposites based on solar photoreduction is here presented. The standard hydro-solvothermal synthesis of the TiO2-rGO composites requires high temperatures and several steps, whereas the proposed one-pot preparation allows one to obtain the photocatalysts with a simple and green procedure, by exploiting the photocatalytic properties of titania activated by the solar irradiation. The TiO2-rGO catalysts were tested in the solar photodegradation of a widely adopted toxic herbicide (2,4-Dichlorophenoxyacetic acid, 2,4-D), obtaining the 97% of degradation after 3 h of irradiation. The as-prepared TiO2-rGO composites were more active compared to the same photocatalysts prepared through the conventional thermal route. The structural, optical, and textural properties of the composites, determined by Raman, Photoluminescence, Fourier Transform InfraRed (FTIR), UV-vis diffuse reflectance (DRS) spectroscopies, and N2 absorption-desorption measurements, showed as the solar irradiation favors the reduction of graphene oxide with higher efficiency compared to the thermal-driven synthesis. Furthermore, the possible toxicity of the as-synthesized composites was measured exposing nauplii of microcrustacean Artemia sp. to solutions containing TiO2-rGO. The good results in the 2,4-D degradation process and the easiness of the TiO2-rGO synthesis allow to consider the proposed approach a promising strategy to obtain performing photocatalysts.

Convalescent Plasma for Pregnant Women with COVID-19: A Systematic Literature Review.

The treatment of COVID-19 is particularly critical in pregnant women, considering the potential teratogenic effects of antiviral agents and the immune-depression related with pregnancy. The aim of this review is to systematically examine the current evidence on the clinical use of convalescent plasma during pregnancy. The electronic databases Medline PubMed Advanced Search Builder, Scopus, Web Of Science and Google Scholar were searched (until 1 January 2021). Inclusion criteria were pregnant women with COVID-19 (or SARS-CoV-2 infection), in whom convalescent plasma (or hyperimmune plasma) was used as treatment. We searched clinical trial registries (censored 5 January 2021) for eligible studies under way. After elimination of duplications, the initial search yielded 79 potentially relevant records, of which 67 were subsequently excluded. The 12 remaining records were case reports involving 12 pregnancies. Six of the mothers were reported to be well, two were reported to have preeclampsia, and in one case each the maternal outcome was described as survival, clinical improvement, discharged with oxygen and rehabilitation. With regard to the neonates, two were declared to be well, four had transient morbidity, two were critically ill and one died; normal ongoing pregnancies, but no post-delivery information, were reported for the remaining three cases. Clinical trials under way or planned to investigate the use of convalescent plasma for COVID-19 during pregnancy are lacking. This is the first systematic review of the literature regarding the treatment of COVID-19 in pregnancy. The published literature data seem to indicate that convalescent plasma administered to pregnant women with severe COVID-19 provides benefits for both the mother and the fetus. The quality of the available studies is, however, very limited since they are all case reports and thus suffer from relevant reporting bias.

Vaginal birth after caesarean section: a multicentre study on prognostic factors and feasibility.

PURPOSE: Vaginal birth after caesarean (VBAC) is an option to avoid major abdominal surgery and many consequences related to repeated caesarean delivery. In the last years, many efforts have been made to increase the number of patients attempting trial of labour after caesarean (TOLAC). The aim of our study was to identify the most important factors associated with the success of VBAC. METHODS: A retrospective study was conducted in two Italian referral centres. Subjects included were singleton and morphologically normal pregnancy with previous C-section. Subjects with an inter-pregnancy interval shorter than 18 months, a large for gestational age baby, a pregnancy complicated with gestational diabetes and a previous unclassified uterine scar were excluded. The characteristics of the subjects were compared and a logistic regression was performed to evaluate variables associated with successful VBAC. RESULTS: Of the 300 patients included, 224 (74.7%) achieved VBAC while 76 (25.3%) underwent C-section after failed TOLAC. The number of previous C-sections was not significantly associated with the success of TOLAC. Factors positively associated with achievement of VBAC were previous vaginal delivery (OR of 6.88 for one and 9.68 for more than one) and oxytocin implementation (OR 3.32). No maternal and neonatal adverse events occurred. CONCLUSION: Our results show that attempting VBAC is a feasible option in referral centres after adequate evaluation of the potential factors affecting the probability of success. A careful record of obstetrical history and management of labour can provide clinicians useful information to counsel women before and during labour.

Three-Dimensional Printing of Fetal Models of Congenital Heart Disease Derived From Microfocus Computed Tomography: A Case Series.

This article presents a case series of n = 21 models of fetal cardiovascular anatomies obtained from post mortem microfocus computed tomography (micro-CT) data. The case series includes a broad range of diagnoses (e.g., tetralogy of Fallot, hypoplastic left heart syndrome, dextrocardia, double outlet right ventricle, atrio-ventricular septal defect) and cases also had a range of associated extra-cardiac malformations (e.g., VACTERL syndrome, central nervous system anomalies, renal anomalies). All cases were successfully reconstructed from the microfocus computed tomography data, demonstrating the feasibility of the technique and of the protocols, including in-house printing with a desktop 3D printer (Form2, Formlabs). All models were printed in 1:1 scale as well as with the 5-fold magnification, to provide insight into the intra-cardiac structures. Possible uses of the models include education and training.

Safety and efficacy of tranexamic acid for prevention of obstetric haemorrhage: an updated systematic review and meta-analysis.

BACKGROUND: A number of clinical systematic review and meta-analysis have been published on the use of tranexamic in the obstetric setting. The aim of this meta-analysis was to evaluate the safety and effectiveness of tranexamic acid in reducing blood loss when given prior to caesarean delivery. MATERIALS AND METHODS: We searched the Cochrane Wounds Specialized Register, Cochrane Central, MEDLINE (through PUBMED), Embase, and SCOPUS electronic databases. We also searched clinical trials registries for ongoing and unpublished studies, and checked reference lists to identify additional studies. We used no restrictions with respect to language and date of publication. Two review authors independently performed study selection, "Risk of bias" assessment, and data extraction. Initial disagreements were resolved by discussion, or by including a third review author when necessary. RESULTS: We found 18 randomised controlled trials (RCTs) that met our inclusion criteria. Overall, 1,764 women receiving intravenous tranexamic acid for prevention of bleeding following caesarean sections and 1,793 controls receiving placebo were enrolled in the 18 RCTs evaluated. The use of tranexamic acid compared to controls (placebo or no intervention) reduces post-partum haemorrhage >400 mL (risk ratio [RR] 0.40, 95% confidence interval [CI] 0.24-0.65; 5 trials with a total of 786 participants), severe post-partum haemorrhage >1,000 mL (RR 0.32, 95% CI: 0.12-0.84; 5 trials with a total of 1,850 participants), and need for red blood cell transfusion (RR 0.30, 95% CI: 0.18-0.49; 10 trials with a total of 1,873 participants). No particular safety concerns on the use of this antifibrinolytic agent emerged from the analysis of the 18 RCTs included. DISCUSSION: Overall, the results of this meta-analysis support the evidence of a beneficial effect of tranexamic acid in reducing blood loss and need for blood transfusion in pregnant women undergoing caesarean section.

Influence of Ulipristal Acetate Therapy on Uterine Fibroid-Related Symptoms and on Uterine and Fibroid Volumes and Vascularity Indices Assessed by Ultrasound.

OBJECTIVES: To investigate the modifications of uterine and fibroid volume, to study Doppler changes in uterine arteries and fibroid-supplying vessels, and to assess possible symptomatic relief after 3 months of treatment with ulipristal acetate. METHODS: Forty-two premenopausal women with symptomatic fibroids were included in the study. They were evaluated clinically for the symptoms reported and underwent ultrasound examinations before starting treatment and after 3 months of therapy with ulipristal acetate. Transvaginal scanning was performed by the same sonographer, who measured the uterine volume and uterine artery pulsatility index and resistive index. Considering that some patients had more than 1 fibroid, the vascularization (supplying vessel pulsatility and resistive indices), locations, and sizes of a total of 73 fibroids were also recorded. RESULTS: After 3 months of ulipristal acetate, patients had a significant improvement of all symptoms (P < .05). The percentage of uterine volume reduction was 14% (P = .03), with fibroid volume reduction of 32.8% (P = .01). Uterine artery vascular indices decreased after treatment, but their reduction did not reach significant results, whereas all fibroid vascular indices decreased significantly after 3 months of ulipristal acetate (P < .05). When the fibroids were divided according to their localization, all had significant volume reduction after therapy, but type 5 had the highest decrease (42%) compared to other fibroid types (P = .03). CONCLUSIONS: Fibroid treatment with ulipristal acetate resulted in a significant improvement of fibroid-related symptoms; moreover, it proved to be effective in decreasing both uterine and fibroid volumes and fibroid vascularization. Type 5 fibroids seem to have the most major response to treatment.

Oral misoprostol vs. vaginal gemeprost prior to surgical termination of pregnancy in nulliparae.

BACKGROUND: To compare the efficacy and side-effects of intravaginal gemeprost with those of oral misoprostol for cervical ripening prior to first-trimester pregnancy termination in nulliparous women. METHODS: Retrospective analysis of surgical terminations of pregnancy performed before 90 days of gestation. Intravaginal gemeprost 1 mg or oral misoprostol 800 micro g was administered 2 h before the procedure. RESULTS: In total, 746 women were enrolled into the study, 84 received intravaginal gemeprost and 662 oral misoprostol. Median baseline cervical dilatation was significantly greater in women who received misoprostol before the operation than in those who received gemeprost (7 mm vs. 3 mm; p < 0.0001). The incidence of fever, vomiting and diarrhea was not different between the two groups. The incidence of abdominal pain with request for pain medication, emergency admission to operating room due to vaginal bleeding, hospital stay longer than 24 h and surgical repair of cervical injury due to Hegar dilatation was significantly higher among the gemeprost group than the misoprostol group. CONCLUSIONS: In cervical priming prior to first-trimester pregnancy termination in nulliparous women, oral misoprostol is more effective and is associated with fewer side-effects and complications than intravaginal gemeprost.

Association between increased nuchal translucency and second trimester cardiac echogenic foci.

OBJECTIVE: To test the hypothesis that increased first trimester nuchal translucency is associated with isolated cardiac foci in the second trimester. METHODS: We identified all pregnancies delivered between January 1997 and June 2000. We included 7686 normal singleton fetuses who had a nuchal translucency scan and either a subsequent normal anomaly scan at 18-23 weeks' gestation (n = 7447) or isolated cardiac foci (n = 239). Fetuses were divided into two groups: normal (95th percentile or less) and increased (greater than 95th percentile) nuchal translucency. RESULTS: The prevalence of cardiac echogenic foci in fetuses with normal nuchal translucency was 218 of 7427 (2.9%; 95% confidence interval [CI] 2.6, 3.3%), whereas 21 of 259 fetuses (8.1%; 95% CI 5.1, 12.1%) with increased nuchal translucency were subsequently found to have cardiac foci. The adjusted odds ratio for cardiac echogenic foci in cases of increased nuchal translucency was 2.92 (95% CI 1.83, 4.66). CONCLUSION: An association exists between first trimester nuchal translucency and second trimester cardiac echogenic foci. Risk calculation algorithms for trisomy 21 based on nuchal translucency thickness should not use cardiac foci as an independent marker.