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1.
Environ Res ; 237(Pt 2): 117062, 2023 Nov 15.
Article in English | MEDLINE | ID: mdl-37660877

ABSTRACT

Psoriasis is one of the most common immune-mediated inflammatory diseases (IMIDs). Living in a rural environment during childhood is associated with a decreased risk of certain IMIDs, like asthma, in adulthood. However, its role in other IMIDs, such as psoriasis is still unclear. To evaluate the relationships between different factors related to the environment during childhood and the risk of psoriasis in adulthood we conducted a study in E3N, a French prospective cohort composed of 98 995 women. During the 1990-2018 follow-up of 72 154 study participants, we identified 1 967 incident cases of psoriasis from self-reports in self-administered structured questionnaires. During the 2004-2018 follow-up of 67 917 study participants, 188 moderate-to-severe cases of psoriasis were identified through self-reports and from data from a drug reimbursement database. We fitted Cox proportional hazards regression models with age as the time scale from which we estimated hazard ratios adjusted for putative confounders (aHRs). We found inverse associations with risk of psoriasis for rural birthplace [aHR: 0.89 (95%CI: 0.79-0.96)] and for having farming parents [aHR: 0.84 (95%CI: 0.72-0.97)]. For moderate-to-severe psoriasis we found a nominally similar inverse association with rural birthplace but not with having farming parents. Our results suggest that an exposure to a rural environment during childhood may be associated with a reduced risk of psoriasis. These findings may help to improve our understanding of the pathogenesis of psoriasis.

2.
Mycopathologia ; 188(4): 307-334, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37294504

ABSTRACT

Endemic systemic mycoses such as blastomycosis, coccidioidomycosis, histoplasmosis, talaromycosis, paracoccidioidomycosis are emerging as an important cause of morbidity and mortality worldwide. We conducted a systematic review on endemic systemic mycoses reported in Italy from 1914 to nowadays. We found out: 105 cases of histoplasmosis, 15 of paracoccidioidomycosis, 10 of coccidioidomycosis, 10 of blastomycosis and 3 of talaromycosis. Most cases have been reported in returning travelers and expatriates or immigrants. Thirtytwo patients did not have a story of traveling to an endemic area. Fortysix subjects had HIV/AIDS. Immunosuppression was the major risk factor for getting these infections and for severe outcomes. We provided an overview on microbiological characteristics and clinical management principles of systemic endemic mycoses with a focus on the cases reported in Italy.


Subject(s)
Blastomycosis , Coccidioidomycosis , Histoplasmosis , Mycoses , Paracoccidioidomycosis , Humans , Histoplasmosis/diagnosis , Histoplasmosis/drug therapy , Histoplasmosis/epidemiology , Coccidioidomycosis/epidemiology , Blastomycosis/epidemiology , Paracoccidioidomycosis/diagnosis , Paracoccidioidomycosis/drug therapy , Paracoccidioidomycosis/epidemiology , Mycoses/drug therapy , Mycoses/epidemiology
3.
Angew Chem Int Ed Engl ; 62(29): e202304306, 2023 Jul 17.
Article in English | MEDLINE | ID: mdl-37208951

ABSTRACT

Benzimidazoles are a versatile class of scaffolds with important biological activities, whereas their synthesis in a lower-cost and more efficient manner remains a challenge. Here, we demonstrate a conceptually new radical route for the high-performance photoredox coupling of alcohols and diamines to synthesize benzimidazoles along with stoichiometric hydrogen (H2 ) over Pd-decorated ultrathin ZnO nanosheets (Pd/ZnO NSs). The mechanistic study reveals the unique advantage of ZnO NSs over other supports and particularly that the features of Pd nanoparticles in facilitating the cleavage of the α-C-H bond of alcohols and adsorbing subsequently-generated C-centered radicals hold the key to turning on the reaction. This work highlights a new insight into radical-induced efficient benzimidazole synthesis pairing with H2 evolution by rationally designing semiconductor-based photoredox systems.

4.
Infect Drug Resist ; 15: 5839-5848, 2022.
Article in English | MEDLINE | ID: mdl-36217342

ABSTRACT

In this study the activity of Isavuconazole, Voriconazole, Amphotericin B, and Caspofungin against 224 clinical isolates of Aspergillus spp. originating from seven Italian hospitals, was comparatively evaluated with two commercial antifungal susceptibility tests (AST): SensititreTM YeastOneTM (SYO) and MIC Test Strip. More attention was focused on Isavuconazole activity, given the new introduction of the drug in widely distributed antifungal susceptibilities methods in the clinical microbiology lab. The minimum inhibitory concentrations of antifungal drug that can inhibit the growth of pathogen by 90% (MIC90) for Isavuconazole detected by SYO were 0.5, 1, 0.25, and 2 µg/mL for Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus, and Aspergillus niger, respectively, whilst they were 0.25, 0.25, 0.5, and 0.75 µg/mL by MIC Test Strip. Essential agreement between the two tested methods for Isavuconazole is 70% for all the species tested, 75.7% for A. fumigatus, 45.2% for A. flavus, 90.6% for A. terreus, and 40% for A. niger. Although the tested strains do not express any phenotypic resistance, MIC results were quite different if tested with microdilution broth or gradient agar method. This is the first Italian multicenter report on Isavuconazole MIC obtained employing the widely used SensititreTM Yeast OneTM (SYO) and MIC Test Strip on clinical isolates of Aspergillus.

5.
ACS Nano ; 16(10): 17444-17453, 2022 10 25.
Article in English | MEDLINE | ID: mdl-36170635

ABSTRACT

Semiconductor-based photoredox catalysis brings an innovative strategy for sustainable organic transformation (e.g., C-C/C-X bond formation), via radical coupling under mild conditions. However, since semiconductors interact with photogenerated radicals unselectively, the precise control of selectivity for such organic synthesis by steering radical conversion is extremely challenging. Here, by the judicious design of a structurally well-defined and atomically dispersed cocatalyst over semiconductor quantum dots, we demonstrate the precise selectivity switch on high-performance selective heterogeneous coupling photosynthesis of a C-C bond or a C-N bond along with hydrogen production over the Ni-oxo cluster and single Pd atom-decorated CdS quantum dots crafted onto the SiO2 support. Mechanistic studies unveil that the Ph(•CH)NH2 and PhCH2NH2•+ act as dominant radical intermediates for such divergent organic synthesis of C-C coupled vicinal diamines and C-N coupled imines, as respectively enabled by Ni-oxo clusters assisted radical-radical coupling and single Pd atom-assisted radical addition-elimination. This work overcomes the pervasive difficulties of selectivity regulation in semiconductor-based photochemical synthesis, highlighting a vista of utilizing atomically dispersed cocatalysts as active sites to maneuver unselective radical conversion by engineering quantum dots toward selective heterogeneous photosynthesis.


Subject(s)
Quantum Dots , Quantum Dots/chemistry , Silicon Dioxide , Semiconductors , Photosynthesis , Hydrogen , Diamines , Imines
6.
Article in English | MEDLINE | ID: mdl-35682382

ABSTRACT

Our study aims at providing evidence on patterns of use of biologic drugs for psoriasis in Tuscany, Italy. We conducted a drug-utilization study based on administrative databanks of Tuscany (EUPAS45365) from 2011 to 2019. We selected new users of etanercept, infliximab, adalimumab, ustekinumab, or secukinumab between 1 January 2011 and 31 December 2016. We considered subjects with psoriasis and followed subjects until the end of the study period (three years after the first dispensation of biologic drug for psoriasis) or the patient's death, whichever came first. We censored subjects for pregnancy or neoplasia. For each subject, we defined the state as the weekly coverage of one of the biologic drugs of interest. We then defined the switch as the change from a state to another one. A total of 7062 subjects with a first dispensation of a PSObio drug in the inclusion period was identified, and 1839 (52.9% female, 51.6 mean age) patients were included in the analysis. Among new users of adalimumab (N = 770, 41.9%), one third showed a continuous behaviour whereas the others moved to etanercept and ustekinumab. New users of etanercept (N = 758, 41.2%), had the highest proportion of switchers, with adalimumab most often being the second choice. New users of infliximab (N = 159, 8.6%) experienced the highest proportion of treatment discontinuation. The present study suggests that the majority of patients treated with PSObio drugs do not switch from one active ingredient to another. However, patients who started biological therapy with etanercept had the highest frequency of switching to other PSObio drugs, whereas those who started with secukinumab or ustekinumab had the lowest.


Subject(s)
Biological Products , Psoriasis , Adalimumab/therapeutic use , Biological Products/therapeutic use , Etanercept/therapeutic use , Female , Humans , Infliximab/therapeutic use , Male , Psoriasis/drug therapy , Psoriasis/epidemiology , Retrospective Studies , Treatment Outcome , Ustekinumab/therapeutic use
8.
Chem Rev ; 121(21): 13051-13085, 2021 11 10.
Article in English | MEDLINE | ID: mdl-34378934

ABSTRACT

Merging hydrogen (H2) evolution with oxidative organic synthesis in a semiconductor-mediated photoredox reaction is extremely attractive because the clean H2 fuel and high-value chemicals can be coproduced under mild conditions using light as the sole energy input. Following this dual-functional photocatalytic strategy, a dreamlike reaction pathway for constructing C-C/C-X (X = C, N, O, S) bonds from abundant and readily available X-H bond-containing compounds with concomitant release of H2 can be readily fulfilled without the need of external chemical reagents, thus offering a green and fascinating organic synthetic strategy. In this review, we begin by presenting a concise overview on the general background of traditional photocatalytic H2 production and then focus on the fundamental principles of cooperative photoredox coupling of selective organic synthesis and H2 production by simultaneous utilization of photoexcited electrons and holes over semiconductor-based catalysts to meet the economic and sustainability goal. Thereafter, we put dedicated emphasis on recent key progress of cooperative photoredox coupling of H2 production and various selective organic transformations, including selective alcohol oxidation, selective methane conversion, amines oxidative coupling, oxidative cross-coupling, cyclic alkanes dehydrogenation, reforming of lignocellulosic biomass, and so on. Finally, the remaining challenges and future perspectives in this flourishing area have been critically discussed. It is anticipated that this review will provide enlightening guidance on the rational design of such dual-functional photoredox reaction system, thereby stimulating the development of economical and environmentally benign solar fuel generation and organic synthesis of value-added fine chemicals.


Subject(s)
Hydrogen , Semiconductors , Catalysis , Chemistry Techniques, Synthetic , Hydrogen/chemistry , Oxidative Stress
9.
J Infect Dev Ctries ; 15(3): 436-441, 2021 03 31.
Article in English | MEDLINE | ID: mdl-33839720

ABSTRACT

Periprosthetic joint infection (PJI) is one of the most dramatic complications of joint arthroplasty. Although streptococcal bone and joint infections are less common than staphylococcal cases, their role as causative agents of bone and joint remains significant accounting for at least 10% of PJIs. Streptococcus anginosus group (SAG) bacteria are usually found in the normal flora of the urogenital tract, intestinal tract and oropharynx and could cause pyogenic infections to affect brain, lungs and liver. SAG bacteria are uncommonly reported as a cause of osteomyelitis and the involvement of a joint represent a rare event. S. anginosus has been anecdotical related to implant devices infections such as vascular prosthesis or orthopedic implants, however, PJI of the knee has never been fully reported before. We describe the case of a late onset periprosthetic knee infection due to Streptococcus anginosus successfully treated by a two-stage revision arthroplasty and postoperative parenteral Vancomycin, (2 g per day) and Levofloxacin (750 mg per day) for 4 weeks and then oral Levofloxacin for a further 2 weeks.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Arthroplasty, Replacement, Knee/adverse effects , Levofloxacin/therapeutic use , Streptococcal Infections/drug therapy , Vancomycin/therapeutic use , Aged , Humans , Knee Joint , Male , Reoperation , Streptococcal Infections/etiology , Streptococcal Infections/microbiology , Streptococcus anginosus/isolation & purification
10.
Front Immunol ; 12: 613070, 2021.
Article in English | MEDLINE | ID: mdl-33815368

ABSTRACT

Lack of specific antiviral treatment for COVID-19 has resulted in long hospitalizations and high mortality rate. By harnessing the regulatory effects of adenosine on inflammatory mediators, we have instituted a new therapeutic treatment with inhaled adenosine in COVID-19 patients, with the aim of reducing inflammation, the onset of cytokine storm, and therefore to improve prognosis. The use of inhaled adenosine in COVID19 patients has allowed reduction of length of stay, on average 6 days. This result is strengthened by the decrease in SARS-CoV-2 positive days. In treated patients compared to control, a clear improvement in PaO2/FiO2 was observed together with a reduction in inflammation parameters, such as the decrease of CRP level. Furthermore, the efficacy of inhaled exogenous adenosine led to an improvement of the prognosis indices, NLR and PLR. The treatment seems to be safe and modulates the immune system, allowing an effective response against the viral infection progression, reducing length of stay and inflammation parameters.


Subject(s)
Adenosine/pharmacology , COVID-19 Drug Treatment , Adenosine/therapeutic use , Adult , Aged , Anti-Bacterial Agents/administration & dosage , Azithromycin/administration & dosage , COVID-19/diagnostic imaging , COVID-19/physiopathology , Case-Control Studies , Cytochrome P-450 CYP3A Inhibitors/administration & dosage , Cytokine Release Syndrome/physiopathology , Enzyme Inhibitors/administration & dosage , Female , Heparin/administration & dosage , Hospitalization , Humans , Hydroxychloroquine/administration & dosage , Inflammation/drug therapy , Lopinavir/administration & dosage , Male , Middle Aged , Prognosis , Tomography, X-Ray Computed
11.
Epilepsy Behav ; 117: 107876, 2021 04.
Article in English | MEDLINE | ID: mdl-33714929

ABSTRACT

PURPOSE: To assess patterns of use of antiseizure medications (ASMs) and to compare the safety of generic versus branded formulations in terms of admission to hospital or to emergency department (ED). METHODS: We conducted a drug utilization study with a propensity score-matched design using the administrative databases of the Italian Tuscany region. New users of ASMs during 2015 with no history of neoplasia were considered and their first prescription was classified as: available only as branded (only-B-ASM); branded with generic available (B-ASM); and generic (G-ASM). Patients with G-ASM first prescription were matched with four patients with B-ASM prescription. Participants were followed up for one year or until the date of death or diagnosis of neoplasia. Cox regression models were fitted to estimate the risk of admission to hospital or ED. RESULTS: We identified 36,601 ASM new-users, including 2094 (6.4%) with only-B-ASM as first prescription, 24,588 (74.9%) with B-ASM, and 5788 (17.6%) with G-ASM. We found no differences in the risk of admission to hospital or ED (Hazard Ratio (HR), 0.92; 95% Confidence Interval (CI), 0.85-1.02) among users of generic ASMs compared to those using branded ASMs. CONCLUSIONS: In our study population, generic ASMs were used less than branded ones. The similarity in the safety of branded and generic formulations suggests that generic ASMs could be the preferred formulation in current clinical practice resulting in a substantial decrease in the cost of treatment.


Subject(s)
Drug Utilization , Drugs, Generic , Databases, Factual , Drugs, Generic/therapeutic use , Humans , Italy , Seizures
12.
Clin Case Rep ; 8(12): 2945-2947, 2020 Dec.
Article in English | MEDLINE | ID: mdl-33363856

ABSTRACT

Atopic dermatitis is associated with a susceptibility to infection usually by Staphylococcus spp due to a decrease of AMPs and Th2 cytokines (eg, IL-17). We reported a rare E. faecalis skin contamination in AD patients due to a frequent contact with excrement.

13.
PLoS One ; 15(10): e0239692, 2020.
Article in English | MEDLINE | ID: mdl-33031409

ABSTRACT

BACKGROUND: SARS-Cov2 infection may trigger lung inflammation and acute-respiratory-distress-syndrome (ARDS) that requires active ventilation and may have fatal outcome. Considering the severity of the disease and the lack of active treatments, 14 patients with Covid-19 and severe lung inflammation received inhaled adenosine in the attempt to therapeutically compensate for the oxygen-related loss of the endogenous adenosine→A2A adenosine receptor (A2AR)-mediated mitigation of the lung-destructing inflammatory damage. This off label-treatment was based on preclinical studies in mice with LPS-induced ARDS, where inhaled adenosine/A2AR agonists protected oxygenated lungs from the deadly inflammatory damage. The treatment was allowed, considering that adenosine has several clinical applications. PATIENTS AND TREATMENT: Fourteen consecutively enrolled patients with Covid19-related interstitial pneumonitis and PaO2/FiO2 ratio<300 received off-label-treatment with 9 mg inhaled adenosine every 12 hours in the first 24 hours and subsequently, every 24 days for the next 4 days. Fifty-two patients with analogue features and hospitalized between February and April 2020, who did not receive adenosine, were considered as a historical control group. Patients monitoring also included hemodynamic/hematochemical studies, CTscans, and SARS-CoV2-tests. RESULTS: The treatment was well tolerated with no hemodynamic change and one case of moderate bronchospasm. A significant increase (> 30%) in the PaO2/FiO2-ratio was reported in 13 out of 14 patients treated with adenosine compared with that observed in 7 out of52 patients in the control within 15 days. Additionally, we recorded a mean PaO2/FiO2-ratio increase (215 ± 45 vs. 464 ± 136, P = 0.0002) in patients receiving adenosine and no change in the control group (210±75 vs. 250±85 at 120 hours, P>0.05). A radiological response was demonstrated in 7 patients who received adenosine, while SARS-CoV-2 RNA load rapidly decreased in 13 cases within 7 days while no changes were recorded in the control group within 15 days. There was one Covid-19 related death in the experimental group and 11in the control group. CONCLUSION: Our short-term analysis suggests the overall safety and beneficial therapeutic effect of inhaled adenosine in patients with Covid-19-inflammatory lung disease suggesting further investigation in controlled clinical trials.


Subject(s)
Adenosine/adverse effects , Coronavirus Infections/drug therapy , Pneumonia, Viral/drug therapy , Adenosine/administration & dosage , Administration, Inhalation , Betacoronavirus/physiology , COVID-19 , Coronavirus Infections/pathology , Coronavirus Infections/physiopathology , Female , Hospitalization , Humans , Lung/pathology , Lung/virology , Lung Diseases, Interstitial/drug therapy , Lung Diseases, Interstitial/virology , Male , Middle Aged , Pandemics , Pneumonia, Viral/pathology , Pneumonia, Viral/physiopathology , Retrospective Studies , SARS-CoV-2
14.
Nat Commun ; 11(1): 5181, 2020 Oct 14.
Article in English | MEDLINE | ID: mdl-33057004

ABSTRACT

The performance of transition metal hydroxides, as cocatalysts for CO2 photoreduction, is significantly limited by their inherent weaknesses of poor conductivity and stacked structure. Herein, we report the rational assembly of a series of transition metal hydroxides on graphene to act as a cocatalyst ensemble for efficient CO2 photoreduction. In particular, with the Ru-dye as visible light photosensitizer, hierarchical Ni(OH)2 nanosheet arrays-graphene (Ni(OH)2-GR) composites exhibit superior photoactivity and selectivity, which remarkably surpass other counterparts and most of analogous hybrid photocatalyst system. The origin of such superior performance of Ni(OH)2-GR is attributed to its appropriate synergy on the enhanced adsorption of CO2, increased active sites for CO2 reduction and improved charge carriers separation/transfer. This work is anticipated to spur rationally designing efficient earth-abundant transition metal hydroxides-based cocatalysts on graphene and other two-dimension platforms for artificial reduction of CO2 to solar chemicals and fuels.

15.
Front Psychol ; 11: 563722, 2020.
Article in English | MEDLINE | ID: mdl-33391079

ABSTRACT

The exceptional pandemic due to the 2019 coronavirus disease (COVID-19) has obliged all Italians to stay at home. In the literature, there are evidences that traumatic global events, such as natural catastrophes and pandemic, have negative effects on the physical and psychological health of the population. We carried out a survey to analyze the physical and psychological conditions of Italians during the pandemic. Due to the severe limitations in moving during the phase one lockdown, the survey was administered by internet. Results show that Italians followed the provisions established by the Italian government to avoid contamination, but 43% of them declared to have suffered from physical symptoms, in particular migraine, sleep disorders, persistent exhaustion, and difficulty of concentration. They have great fear to be contaminated or that relatives or friends can be contaminated, and they actively take actions to avoid contamination. Participants declared that they had suffered a lot of inconveniences due to restrictions in their movements, and that their life habits were strongly changed. They spent their time at home in different activities, but their psychological well-being was strongly impaired by the lockdown. The level of anxiety tripled, in relation to the prepandemic period, and 30% of males and 41% of females declared to have severe levels of depression. Participants with high levels of optimism and hopefulness show a stronger resilience against anxiety and depression. In addition, there is a negative correlation between anxiety and depression and the five factors of personality. These results show that psychological diseases must not be neglected, and that people in lockdown do need support for their psychological health, also with the help of internet and communication technologies.

16.
Int J Med Microbiol ; 309(3-4): 182-188, 2019.
Article in English | MEDLINE | ID: mdl-30878541

ABSTRACT

Meningococcal disease incidence in Italy remains quite low in the overall population except for infants. Within a study on carriage isolates among high school students we aimed to define: i) the prevalence of carriage isolates, ii) the phenotypic and iii) the molecular features of meningococci by Whole Genome Sequencing (WGS). A total of 1697 pharyngeal samples from undergraduate students (age range 14-19 years) were collected from 2012 to 2013 from six larger cities in Italy. One hundred and twenty culture positive meningococci (7%) were analyzed. Carriage isolates were sent to the National Reference Laboratory for invasive meningococcal disease (IMD) for PCR-based serogroup identification, Multilocus Sequence Typing, PorA and FetA typing. Moreover, factor H binding protein (fHbp), Neisseria Heparin Binding Antigen (NHBA) and Neisserial adhesin A (NadA) were typed. Core genome MLST (cgMLST) was performed on a subsample of 75 carriage isolates. Capsule null locus (cnl) predominated (47%), followed by serogroup B (27%). The antimicrobial susceptibility profile revealed an high prevalence of reduced susceptibility to penicillin G (54%) and a full susceptibility to ceftriaxone, ciprofloxacin and rifampicin. Carriage isolates presented a high genetic diversity: the clonal complexes (ccs) cc1136, cc198 and cc41/44, were the predominant. An high heterogeneity was also observed for PorA and FetA types. The fhbp and nhba genes were identified in all the carriage isolates; only 5% of the carriage isolates presented the nadA gene. The core genome MLST analysis revealed that the majority of the cnl isolates clustered in a distinct group. The evidence gathered during this study provides the estimate of carriage isolates in high school students in a non-epidemic period in Italy that was lower than expected. Moreover, the highest proportion of carriage isolates were cnl and, overall, they were molecular heterogeneous.


Subject(s)
Bacterial Capsules/genetics , Carrier State/microbiology , Meningococcal Infections/microbiology , Neisseria meningitidis/isolation & purification , Adolescent , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Carrier State/epidemiology , DNA, Bacterial/genetics , Female , Genetic Variation , Genome, Bacterial/genetics , Genotype , Humans , Italy/epidemiology , Male , Meningococcal Infections/epidemiology , Microbial Sensitivity Tests , Multilocus Sequence Typing , Neisseria meningitidis/classification , Neisseria meningitidis/drug effects , Neisseria meningitidis/genetics , Pharynx/microbiology , Phylogeny , Prevalence , Sequence Analysis, DNA , Serogroup , Students , Young Adult
17.
Chemistry ; 23(49): 11834-11842, 2017 Sep 04.
Article in English | MEDLINE | ID: mdl-28295756

ABSTRACT

The liquid-phase oxidation of cyclohexane to cyclohexanol and cyclohexanone was investigated by synthesizing and testing an array of heterogeneous catalysts comprising: monometallic Ag/MgO, monometallic Pd/MgO and a set of bimetallic AgPd/MgO catalysts. Interestingly, Ag/MgO was capable of a conversion comparable to current industrial routes of approximately 5 %, and with a high selectivity (up to 60 %) to cyclohexanol, thus making Ag/MgO an attractive system for the synthesis of intermediates for the manufacture of nylon fibres. Furthermore, following the doping of Ag nanoparticles with Pd, the conversion increased up to 10 % whilst simultaneously preserving a high selectivity to the alcohol. Scanning transmission electron microscopy and energy dispersive spectroscopy of the catalysts showed a systematic particle-size-composition variation with the smaller Ag-Pd nanoparticles being statistically richer in Pd. Analysis of the reaction mixture by electron paramagnetic resonance (EPR) spectroscopy coupled with the spin-trapping technique showed the presence of large amounts of alkoxy radicals, thus providing insights for a possible reaction mechanism.

18.
Langmuir ; 33(12): 2965-2976, 2017 03 28.
Article in English | MEDLINE | ID: mdl-28267340

ABSTRACT

Nanocrystalline hydroxyapatite (nanoHA) is the main hard component of bone and has the potential to be used to promote osseointegration of implants and to treat bone defects. Here, using active pharmaceutical ingredients (APIs) such as ibuprofen, we report on the prospects of combining nanoHA with biologically active compounds to improve the clinical performance of these treatments. In this study, we designed and investigated the possibility of API attachment to the surface of nanoHA crystals via the formation of a hydrogen-bonded complex. The mechanistic studies of an ibuprofen/nanoHA complex formation have been performed using a holistic approach encompassing spectroscopic (Fourier transform infrared (FTIR) and Raman) and X-ray diffraction techniques, as well as quantum chemistry calculations, while comparing the behavior of the ibuprofen/nanoHA complex with that of a physical mixture of the two components. Whereas ibuprofen exists in dimeric form both in solid and liquid state, our study showed that the formation of the ibuprofen/nanoHA complex most likely occurs via the dissociation of the ibuprofen dimer into monomeric species promoted by ethanol, with subsequent attachment of a monomer to the HA surface. An adsorption mode for this process is proposed; this includes hydrogen bonding of the hydroxyl group of ibuprofen to the hydroxyl group of the apatite, together with the interaction of the ibuprofen carbonyl group to an HA Ca center. Overall, this mechanistic study provides new insights into the molecular interactions between APIs and the surfaces of bioactive inorganic solids and sheds light on the relationship between the noncovalent bonding and drug release properties.

19.
J Phys Chem A ; 120(34): 6677-87, 2016 Sep 01.
Article in English | MEDLINE | ID: mdl-27510306

ABSTRACT

The stereochemistry and dynamics of MoO2(acac)2 in benzene, chloroform, and toluene were investigated by variable temperature (1)H NMR, density functional theory (SOGGA11-X, B3LYP), and ab initio (MP2) methods. In solution, an equilibrium between two chiral enantiomers with C2 symmetry was identified, Λ-cis-MoO2(acac)2 and Δ-cis-MoO2(acac)2. The two enantiomers are connected via achiral cis transition states that switch the enantiomeric conformations via a Ray-Dutt, Bailar, and a newly described racemization twisting mechanism. All three mechanisms have similar calculated activation energies. Activation parameters Ea, ΔH(‡), and ΔS(‡) were experimentally determined for the exchange process, with a small, negative ΔS(‡), and a positive ΔH(‡) of 68.1 kJ mol(-1) in benzene, 54.9 kJ mol(-1) in chloroform, and 60.6 kJ mol(-1) in toluene, in reasonable general agreement with the calculations. Trans configurations of MoO2(acac)2 are very much higher in energy than cis and are not relevant in the temperature range experimentally studied, 243-340 K. The enantiomers interconvert within seconds near room temperature and much faster at elevated temperatures. Racemization will thus prevent the use of enantiomerically pure MoO2(acac)2 for chiral catalysis under practical conditions.

20.
Phys Chem Chem Phys ; 17(2): 715-31, 2015 Jan 14.
Article in English | MEDLINE | ID: mdl-25259662

ABSTRACT

The activation and use of oxygen for the oxidation and functionalization of organic substrates are among the most important reactions in a chemist's toolbox. Nevertheless, despite the vast literature on catalytic oxidation, the phenomenon of autoxidation, an ever-present background reaction that occurs in virtually every oxidation process, is often neglected. In contrast, autoxidation can affect the selectivity to a desired product, to those dictated by pure free-radical chain pathways, thus affecting the activity of any catalyst used to carry out a reaction. This critical review compares catalytic oxidation routes by transition metals versus autoxidation, particularly focusing on the industrial context, where highly selective and "green" processes are needed. Furthermore, the application of useful tests to discriminate between different oxygen activation routes, especially in the area of hydrocarbon oxidation, with the aim of an enhanced catalyst design, is described and discussed. In fact, one of the major targets of selective oxidation is the use of molecular oxygen as the ultimate oxidant, combined with the development of catalysts capable of performing the catalytic cycle in a real energy and cost effective manner on a large scale. To achieve this goal, insights from metallo-proteins that could find application in some areas of industrial catalysis are presented, as well as considering the physicochemical principles that are fundamental to oxidation and autoxidation processes.

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