Ultraviolet light phototherapy for allergic rhinitis

Phototherapy has a profound immunosuppressive effect and is widely used for the treatment of immune mediated skin diseases. Phototherapy is able to inhibit immediate type hypersensitivity reaction in the skin. Intranasal phototherapy is a new approach for treatment of allergic rhinitis. In two open studies, 308 nm excimer laser and topical PUVA therapy efficiently inhibited clinical symptoms of allergic rhinitis. In a randomized, double-blind study combined low dose UVB, low dose UVA and visible light proved to be effective in reducing symptom scores for sneezing, rhinorrhea, nasal itching and the total nasal score in ragweed allergic patients. Mechanism of action of phototherapy is complex, it reduces the antigen presenting capacity of dendritic cells, induces apoptosis of immune cells and inhibits synthesis and release of pro-inflammatory mediator from several cell types. Therefore, intranasal phototherapy may represent an alternative treatment of allergic rhinitis and other inflammatory and immune mediated mucosal diseases.     

Intranasal phototherapy is more effective than fexofenadine hydrochloride in the treatment of seasonal allergic rhinitis: results of a pilot study

We recently showed that intranasal phototherapy represents an efficient therapeutic modality for the treatment of patients with seasonal allergic rhinitis (SAR). The aim of this pilot study was to compare the efficacy of intranasal phototherapy with that of the new generation antihistamine fexofenadine HCl in SAR. A randomized open study was conducted in patients with a history of moderate-to-severe ragweed-induced SAR. Thirty-one patients were randomly assigned to receive either intranasal irradiation three times a week for 2 weeks, or 180 mg fexofenadine HCl per day for 2 weeks. Each patient kept a diary of symptoms for nasal obstruction, nasal itching, rhinorrhea, sneezing and palate itching. Total nasal score (TNS), a sum of scores for nasal symptoms, was also calculated. In the rhinophototherapy group the individual scores significantly decreased compared with baseline for all of the parameters. In the fexofenadine HCl group none of the scores improved significantly at the end of the treatment except sneezing. TNS was significantly decreased in the rhinophototherapy group, but no significant change was observed in the fexofenadine HCl group after 2 weeks of treatment. In conclusion, we found that intranasal phototherapy is more efficient than fexofenadine HCl in reducing clinical symptoms for SAR.     

Intranasal irradiation with the xenon chloride ultraviolet B laser improves allergic rhinitis

We earlier reported that the 308 nm xenon chloride (XeCl) ultraviolet B (UVB) laser is highly effective for the treatment of inflammatory skin diseases. Since UVB irradiation has been shown to exert both local and systemic immunosuppression, we investigated the clinical efficacy of UVB irradiation in allergic rhinitis. In an open study, groups of patients with severe allergic rhinitis received intranasal irradiation with a 308 nm XeCl UVB excimer laser for two weeks. In the low-dose group (n=10), treatment was given twice weekly, starting with 0.25x the individual minimal erythema dose (MED), whereas patients in the medium-dose group (n=8) were treated four times weekly, starting with 0.4x MED. In each group, the dosage was gradually increased. Evaluation was based on the symptom scores. The effect of the XeCl laser on the skin prick test reaction was also studied. In the low-dose group, seven patients completed the study, and there was no improvement in the nasal symptoms. In the medium-dose group, the XeCl UVB irradiation significantly inhibited the rhinorrhoea, the sneezing, the nasal obstruction and the total nasal score (p<0.05). The XeCl UVB excimer laser also inhibited the allergen-induced skin prick test in a dose-dependent manner. These results suggest that the XeCl UVB excimer laser might serve as a new therapeutic tool in the treatment of allergic rhinitis.     

Acute Ultraviolet Radiation Perturbs Epithelialization but not the Biomechanical Strength of Full‐thickness Cutaneous Wounds

We hypothesized that priming of the skin with ultraviolet radiation (UVR) before being injured would enhance wound healing. Four groups, each comprising 20 immunocompetent hairless mice, were exposed to simulated solar irradiation in escalating UVR doses; 0 standard erythema dose (SED) = control, 1 SED, 3 SED and 5 SED. Twenty‐four hours after UV irradiation, inflammation was quantified by skin reflectance (erythema) and myeloperoxidase (MPO) tissue levels, and two 6 mm full‐thickness excisional wounds and one 3 cm incisional wound were inflicted. Epidermal hyperplasia was assessed by quantitative histology. Five days after wounding, wound coverage by neoepithelium and wound width of the excisional wounds was quantified in hematoxylin–eosin sections, and breaking strength was measured in strips from incisional wounds. Erythema (P < 0.001), MPO levels (P < 0.0005) and epidermal cell layers (P < 0.001) increased dose‐dependently by UV exposure of dorsal skin. In the excisional wounds, epithelial coverage decreased (P = 0.024) by increasing the UVR dose, whereas there was no significant difference (P = 0.765) in wound MPO levels. Neither wound width (P = 0.850) nor breaking strength (P = 0.320) differed among the groups. Solar‐simulated UVR 24 h before wounding impaired epithelialization but was not detrimental for surgical incisional wound healing.     

PUVA treatment of the nasal cavity improves the clinical symptoms of allergic rhinitis and inhibits the immediate-type hypersensitivity reaction in the skin

We earlier reported that intranasal irradiation with the 308 nm xenon chloride (XeCl) ultraviolet-B laser and irradiation with a combination of ultraviolet-B (UVB), ultraviolet-A (UVA) and visible light (VIS) is highly effective in the treatment of allergic rhinitis and inhibit the immediate-type hypersensitivity reaction in the skin. Since photochemotherapy with 8-methoxypsoralen (8-MOP) plus UVA light (PUVA) is widely used in the treatment of different inflammatory skin disorders due to its immunosuppressive effect, in the present study we investigated the efficacy of intranasal PUVA treatment in allergic rhinitis and the effect of PUVA treatment on the skin prick test (SPT) reaction. An open study was performed in 17 patients with hay fever. Intranasal PUVA therapy was given four times weekly for 3 weeks. The treatment was started with a fluence of 0.5x of the individual minimal phototoxic dose (MPD) and the dosages were gradually increased. Evaluation was based on the symptom scores. The effect of PUVA treatment on the allergen-induced wheal formation was also studied in the SPT. PUVA treatment of the nasal cavity significantly decreased the nasal symptoms of the patients with allergic rhinitis. Treatment of the skin with PUVA also significantly suppressed the allergen-induced wheal formation in the SPT reaction. These data suggest that intranasal PUVA phototherapy is also an effective modality in the treatment of allergic rhinitis.     

Histopathological evaluation of the effect of intranasal phototherapy on nasal mucosa in rabbits

Allergic rhinitis is a high-incidence allergic inflammation of the nasal airways that impacts quality of life. Of the numerous therapies used to treat allergic rhinitis, intranasal phototherapy has emerged as a promising new treatment modality for inflammatory airway disease. Phototherapy is widely used for the treatment of immune-mediated skin diseases because its profound immunosuppressive effect inhibits hypersensitivity reactions in the skin. Intranasal phototherapy using a combination of Ultraviolet-A (UVA) and Ultraviolet-B (UVB) plus Visible light (VIS) has been shown to suppress the clinical symptoms of allergic rhinitis, but limited data regarding its adverse effects on the nasal mucosa currently exists. In this study, we demonstrate that UV displays no harmful effects on the nasal mucosa cells of rabbits following 2 weeks of intranasal phototherapy.     

Sun exposure and Protection Behavior of Danish Farm Children: Parental Influence on Their Children

Healthy sun habits acquired in childhood could reduce skin cancer incidence. We examined the sun exposure and protection behavior of an expected high‐exposure group of children, and the association to their parents. Open, prospective cohort study. One hundred and thirty nine participants (40 families) kept daily sun behavior diaries (sun exposure, sunscreen use, sunburns) over a 4‐month summer period (15 985 diary days). The Pigment Protection Factor (PPF), an objective measure of sun exposure, was measured at two body sites, before and after summer. All participants presented data from the same 115 days. Risk behavior (sun exposure of upper body) took place on 9.5 days (boys) and 15.6 days (girls). Sunburn and sunscreen use were infrequent. Boys’ sun exposure resulted in an increased photo protection over the study period of 1.7 SED (upper arm) and 0.8 SED (shoulder) to elicit erythema. Corresponding values for girls were as follows: 0.9 SED (upper arm) and 0.5 SED (shoulder). Boys’ sunscreen use correlated to their mothers’ (r = 0.523, P = 0.02). Girls’ number of risk days (r = 0.552, P = 0.005) and sun exposure (upper arm: r = 0.621, P < 0.001) correlated to their mothers’. The children's sun exposure was substantial. Only mothers influenced children's sun behavior and exposure. This may be of relevance in future sun protection campaigns.     

The Immuno-Modulatory Activities of Pentaherbs Formula on Ovalbumin-Induced Allergic Rhinitis Mice via the Activation of Th1 and Treg Cells and Inhibition of Th2 and Th17 Cells

Allergic rhinitis (AR) is a highly prevalent allergic disease induced by immunoglobulin (Ig) E-mediated hypersensitivity reaction at the nasal epithelium against inhaled allergens. Previous studies have demonstrated that Pentaherbs formula (PHF), a modified herbal formula comprising five herbal medicines (Flos Lonicerae, Herba Menthae, Cortex Phellodendri, Cortex Moutan and Rhizoma Atractylodis), could suppress various immune effector cells to exert anti-inflammatory and anti-allergic effects in allergic asthma and atopic dermatitis. The present study aimed to further determine the anti-inflammatory activities of PHF in an ovalbumin (OVA)-induced AR BALB/c mouse model. Nasal symptoms such as sneezing and nose rubbing were recorded and the serum total IgE and OVA-specific IgG1, as well as interleukin (IL)-4, IL-5, IL-10, IL-13, chemokines CXCL9 CXCL10, and tumor necrosis factor (TNF)-α concentrations in nasal lavage fluid (NALF) were measured during different treatments. Effects of PHF on the expression of inflammatory mediators in the sinonasal mucosa were quantified using real-time QPCR. PHF was found to suppress allergic symptoms, infiltration of inflammatory cells, and hyperplasia of goblet cells in the nasal epithelium of the OVA-induced AR mice. PHF could reduce OVA-specific IgG1 level in serum, and TNF-α and IL-10 in nasal lavage fluid (NALF), significantly up-regulate the splenic regulatory T (Treg) cell level, increase the Type 1 helper T cell (Th1)/Type 2 helper T cell (Th2) ratio, and reduce the Th17 cells (all p < 0.05). PHF could also alleviate in situ inflammation in sinonasal mucosa of OVA-induced AR mice. In conclusion, oral treatment of PHF showed immuno-modulatory activities in the OVA-induced AR mice by regulating the splenic T cell population to suppress the nasal allergy symptoms and modulating inflammatory mediators, implicating that PHF could be a therapeutic strategy for allergic rhinitis.     

Effects of intranasal phototherapy on nasal mucosa in patients with allergic rhinitis

RATIONALE: Rhinophototherapy has been shown to be effective in the treatment of allergic rhinitis. Considering that phototherapy with ultraviolet light (UV) induces DNA damage, it is of outstanding importance to evaluate the damage and repair process in human nasal mucosa. METHODS: We have investigated eight patients undergoing intranasal phototherapy using a modified Comet assay technique and by staining nasal cytology samples for cyclobutane pyrimidine dimers (CPDs), which are UV specific photoproducts. RESULTS: Immediately after last treatment Comet assay of nasal cytology samples showed a significant increase in DNA damage compared to baseline. Ten days after the last irradiation a significant decrease in DNA damage was observed compared to data obtained immediately after finishing the treatment protocol. Difference between baseline and 10 days after last treatment was not statistically significant. Two months after ending therapy, DNA damage detected by Comet assay in patients treated with intranasal phototherapy was similar with that of healthy individuals. None of the samples collected before starting intranasal phototherapy stained positive for CPDs. In all samples collected immediately after last treatment strong positive staining for CPDs was detected. The number of positive cells significantly decreased 10 days after last treatment, but residual positive staining was present in all the examined samples. This finding is consistent with data reported in skin samples after UV irradiation. Cytology samples examined two months after ending therapy contained no CPD positive cells. CONCLUSION: Our results suggest that UV damage induced by intranasal phototherapy is efficiently repaired in nasal mucosa.     

Disinfect Porphyromonas gingivalis Biofilm on Titanium Surface with Combined Application of Chlorhexidine and Antimicrobial Photodynamic Therapy

Various antimicrobial modalities have been proposed to treat peri‐implantitis but resulted in limited outcomes. The aim of this in vitro study was to evaluate the disinfection efficacy of combined application of chlorhexidine digluconate (CHX) and antimicrobial photodynamic therapy (aPDT) of titanium surfaces previously contaminated with Porphyromonas gingivalis biofilm. P. gingivalis biofilms were grown on 32 polished and 32 sandblasted large‐grit acid‐etched (SLA) titanium surfaces. Titanium disks were allocated into four groups as follows: (1) immersed in phosphate‐buffered saline (PBS), (2) immersed in 0.2% CHX, (3) application of aPDT and (4) immersed in 0.2% CHX and subsequent aPDT. Residual bacteria were determined by microbial culture analysis and by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) imaging. Combination protocol (CHX+ aPDT) was the most effective in eradicating P. gingivalis (P < 0.05) on both polished and SLA surfaces. There was no significant difference in the number of remaining P. gingivalis between polished titanium disks and the SLA ones in four groups (P > 0.05). Under the limitation of this study, combined technique of preceding application of CHX and subsequent aPDT was shown to be an efficient method in reducing P. gingivalis numbers in both polished and SLA titanium surfaces.     

Effects of Low‐Level Laser Therapy (LLLT) and Diclofenac (Topical and Intramuscular) as Single and Combined Therapy in Experimental Model of Controlled Muscle Strain in Rats

Muscle injuries represent ca 30% of sports injuries and excessive stretching of muscle causes more than 90% of injuries. Currently the most used treatments are nonsteroidal anti‐inflammatory drugs (NSAIDs), however, in last years, low‐level laser therapy (LLLT) is becoming an interesting therapeutic modality. The aim of this study was to evaluate the effect of single and combined therapies (LLLT, topical application of diclofenac and intramuscular diclofenac) on functional and biochemical aspects in an experimental model of controlled muscle strain in rats. Muscle strain was induced by overloading tibialis anterior muscle of rats. Injured groups received either no treatment, or a single treatment with topical or intramuscular diclofenac (TD and ID), or LLLT (3 J, 810 nm, 100 mW) 1 h after injury. Walking track analysis was the functional outcome and biochemical analyses included mRNA expression of COX‐1 and COX‐2 and blood levels of prostaglandin E₂ (PGE₂). All treatments significantly decreased COX‐1 and COX‐2 gene expression compared with injury group (P < 0.05). However, LLLT showed better effects than TD and ID regarding PGE₂ levels and walking track analysis (P < 0.05). We can conclude that LLLT has more efficacy than topical and intramuscular diclofenac in treatment of muscle strain injury in acute stage.     

Spectroscopic Study of the E/Z Photoisomerization of a New Cyrhetrenyl Acylhydrazone: A Potential Photoswitch and Photosensitizer†

The new cyrhetrenyl acylhydrazone [(CO)₃Re(η⁵‐C₅H₄)‐C(O)‐NH‐N = C(CH₃)‐(2‐C₄H₂S‐5‐NO₂)] ( E‐CyAH ) has been designed, synthesized and fully characterized to study the effect of having a cyrhetrenyl fragment (sensitizer) covalently bonded to an acylhydrazone moiety (switch), on its photophysical and photochemical properties. The crystal structure reveals that E‐CyAH adopts an E‐configuration around the iminic moiety [‐N = C(CH₃)]. The absorption spectrum of E‐CyAH displays two bands at 270 and 380 nm, which are mainly ascribed to π → π* intraligand (IL) and d_π → π* metal‐to‐ligand charge transfer (MLCT) transitions, being consistent with DFT/TD‐DFT calculations. Upon 365 nm irradiation, E‐CyAH photoisomerizes to Z‐CyAH , as evidenced by UV‐Vis and ¹H‐NMR spectral changes, with a quantum yield value Φ_{E‐CyAH →Z‐CyAH} of 0.30. Z‐CyAH undergoes a first‐order thermal back‐isomerization process, with a relatively short half‐life τ_1/2 of 277 min. Consequently, E‐CyAH was quantitatively recovered after 24 h, making it a fully reversible T‐type molecular photoswitch. This remarkable behavior allows us to measure the individual photophysical properties for both isomers. In addition, E‐CyAH and Z‐CyAH efficiently photosensitize the generation of singlet oxygen (O₂ (¹Δ_g)) with good yield (Φ_Δ = 0.342).     

Analgesic Effect of Light‐Emitting Diode (LED) Therapy at Wavelengths of 635 and 945 nm on Bothrops moojeni Venom‐Induced Hyperalgesia

Envenoming induced by Bothrops snakes is characterized by drastic local tissue damage involving hemorrhage, myonecrosis and proeminent inflammatory and hyperalgesic response. The most effective treatment is antivenom therapy, which is ineffective in neutralizing the local response. Herein, it was evaluated the effectiveness of light‐emitting diode (LED) at wavelengths of 635 and 945 nm in reducing inflammatory hyperalgesia induced by Bothrops moojeni venom (BmV) in mice, produced by an subplantar injection of BmV (1 μg). Mechanical hyperalgesia and allodynia were assessed by von Frey filaments at 1, 3, 6 and 24 h after venom injection. The site of BmV injection (1.2 cm²) was irradiated by LEDs at 30 min and 3 h after venom inoculation. Both 635 nm (110 mW, fluence of 3.76 J/cm² and 41 s of irradiation time) and 945 nm (120 mW, fluence of 3.8 J/cm² and 38 s of irradiation time) LED inhibited mechanical allodynia and hyperalgesia of mice alone or in combination with antivenom treatment, even when the symptoms were already present. The effect of phototherapy in reducing local pain induced by BmV should be considered as a novel therapeutic tool for the treatment of local symptoms induced after bothropic snake bites.     

Synthesis of iron‐based metal organic framework and its visible light‐driven photocatalytic degradation of dye pollutants

A novel metal–organic compound [Fe (ox)(phen)]_n (phen = 1,10‐Phennannthroline, ox = oxalate acid) has been hydrothermally synthesized and structurally characterized by X‐ray single‐crystal diffraction, X‐ray diffraction, IR, UV–vis diffuse reflectance spectroscopy and X‐ray photoelectron spectroscopy. The compound crystallized in monoclinic,space group P2₁ with a = 0.92289 (3) nm, b = 1.35719 (3) nm, c = 1.02012 (4) nm,β = 94.372 (2)°,V = 1.27402(8)nm³,Z = 2,and exhibited a 2D layer structure. The photocatalytic activities of the compound were evaluated by decomposing Rhodamine B (RhB) and methyl orange (MO) under the visible light irradiation. In addition, the mechanism of the photocatalytic properties were proposed during this process.     

Synthesis,Structures and Various Biological Applications of New Zn(II) Complexes Having Different Coordination Modes Controlled by the Drug Furosemide in Presence of Bioactive Nitrogen Based Ligands

Novel Zn(II) complexes with the general formula: [Zn(furo)₂(L)_n], n = 1 or 2, (furo = furosemide = (4‐chloro‐2‐(furan‐2‐ylmethylamino)‐5‐sulfamoylbenzoic acid) were prepared. The complexes [Zn(furo)₂(MeOH)₂] ( 1 ; MeOH = methanol), [Zn(furo)₂(2‐ampy)₂] ( 2 ; 2‐ampy = 2‐aminopyridine), [Zn(furo)₂(2‐ammepy)₂] ( 3 ; 2‐ammepy = 2‐aminomethylpyridine), [Zn(furo)₂(H₂O)(2,2‐bipy)] ( 4 ; 2,2′‐bipy = 2,2′‐bipyridine), [Zn(furo)₂(H₂O)(4,4′‐bipy)] ( 5 ; 4,4′‐bipy = 4,4′‐bipyridine), [Zn(furo)₂(1,10‐phen)] ( 6 ; 1,10‐phen = 1,10‐phenanthroline), [Zn(furo)₂(2,9‐dmp)] ( 7 ; 2,9‐dmp = 2,9‐dimethyl‐1,10‐phenanthroline), and [Zn (furo)₂(quin)₂] ( 8 ; quin = quinoline) were synthesized and characterized using different techniques such as IR, UV–Vis, ¹H NMR, ¹³C NMR, LC/MS and others. The crystal structure of complex ( 4 ) was determined using single‐crystal X‐ray diffraction. The anti‐bacterial activity of complexes ( 1 – 8 ) was tested using agar diffusion method against three gram‐positive (Staphylococcus aureus, Bacillus subtilis and Staphylococcus epidermidis) and three gram‐negative bacteria (Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa). The obtained results showed different Inhibition Zone Diameters (IZD) with various anti‐bacterial activities against the selected gram‐positive and gram‐negative bacteria. In addition, the rate of bis‐(4‐nitrophenyl) phosphate hydrolysis was measured at different temperatures, different pH values and different concentrations. The rates for the eight complexes were in the following order: complex 4 > 2 > 5 > 8  >  7  >  6  >  3  >  1 .     

Titanium complexes bearing amine bis(phenolate) ligands: Synthesis,structure and catalysis in ring‐opening polymerization of lactide

Monomeric bis(isopropoxy) titanium complexes LTi(Oⁱ Pr)₂ (L =  ─ OC₆H₂–4‐R¹–6‐R²–2‐CH₂N[(CH₂)₂N(R³)₂]CH₂–4‐R⁴–6‐R⁵‐C₆H₂O ─ , R¹ = R² = ^t Bu, R³ = Et, R⁴ = R⁵ = Cl, (L¹)Ti(Oⁱ Pr)₂; R¹ = R² = Me, R³ = Et, R⁴ = R⁵ = Me, (L²)Ti(Oⁱ Pr)₂; R¹ = R² = ^t Bu, R³ = Et, R⁴ = OMe, R⁵ = ^t Bu, (L³)Ti(Oⁱ Pr)₂; R¹ = R⁴ = OMe, R³ = Et, R² = R⁵ = ^t Bu, (L⁴)Ti(Oⁱ Pr)₂; R¹ = R² = ^t Bu, R³ = Me, R⁴ = OMe, R⁵ = ^t Bu, (L⁵)Ti(Oⁱ Pr)₂) supported by amine bis(phenolate) ligands were synthesized and characterized using NMR spectroscopy and elemental analysis. The solid‐state structure of (L³)Ti(Oⁱ Pr)₂ was determined using single‐crystal X‐ray diffraction. (L^1–5)Ti(Oⁱ Pr)₂ were all found to initiate the ring‐opening polymerization of l ‐lactide and rac ‐lactide in a controlled manner at 110–160°C. As shown by kinetic studies, (L¹)Ti(Oⁱ Pr)₂ polymerized l ‐lactide faster than did (L^2–5)Ti(Oⁱ Pr)₂. In addition, good number‐average molecular weight and narrow polydispersity index (1.00–1.71) of polymers were also obtained. The microstructure of the polymers and a possible mechanism of coordination–insertion of polymerization were evidenced by MALDI‐TOF and ¹H NMR spectra of the polylactides.     

On the Formation of Thymine Photodimers in Thymine Single Strands and Calf Thymus DNA

Solar light leads to thymine dimers that are mutagenic and primary cause of skin cancer. Here, we report absorption and synchrotron radiation circular dichroism (CD) spectra of T_n single strands with different number n of bases (n = 2–7, 10, 11) recorded after various 254 nm irradiation times. From a principal component analysis of the CD spectra, we extract fingerprint spectra of both the cyclobutane pyrimidine dimer (CPD) and the pyrimidine (6‐4) pyrimidone photoadduct (64PP). Extending the CD measurements to the vacuum ultraviolet region in combination with systematic examinations of size effects is a new approach to gain insight on the dimeric photoproducts. We find a simple linear correlation between n and average number of dimers formed after 1 h of irradiation. The probability for a thymine to engage in a dimer increases from 32% for n = 2 to 41% for n = 11, which implies limited effects of terminal thymines, i.e., the reaction does not occur preferentially at the extremities of the single strands as previously stated. It is even possible to form two dimers with only two bridging thymines. Finally, experiments conducted on calf thymus DNA provided a similar signature of the photodimer, but differences are also evident.     

Vanadium(III) complexes containing phenoxy–imine–thiophene ligands: Synthesis,characterization and application to homo‐ and copolymerization of ethylene

A set of vanadium(III) complexes, namely {SNO}VCl₂(THF)₂ ( 2a , SNO = thiophene‐(N═CH)‐phenol; 2b , SNO = 5‐phenylthiophene‐(N═CH)‐phenol; 2c , SNO = 5‐phenylthiophene‐(N═CH)‐4‐tert ‐butylphenol; 2d , SNO = 5‐methylthiophene‐(N═CH)‐phenol; 2e , SNO = 5‐methylthiophene‐(N═CH)‐4‐tert ‐butylphenol; 2f , SNO = 5‐methylthiophene‐(N═CH)‐2‐methylphenol; 2g , SNO = 5‐methylthiophene‐(N═CH)‐4‐fluorophenol), were synthesized by reaction of VCl₃(THF)₃ with phenoxy–imine–thiophene proligands ( 1a – g ). All vanadium(III) complexes were characterized using elemental analysis and infrared and electron paramagnetic resonance spectroscopies. Upon activation with methylaluminoxane (MAO), vanadium precatalysts 2a – g proved active in the polymerization of ethylene (213.6–887.2 kg polyethylene (mol[V])⁻¹⋅h⁻¹), yielding high‐density polyethylenes with melting temperatures in the range 133–136 °C and crystallinities varying from 28 to 41%. The 2e/ MAO catalyst system was able to copolymerize ethylene with 1‐hexene affording poly(ethylene‐co ‐1‐hexene)s with melting temperatures varying from 126 to 102 °C and co‐monomer incorporation in the range 3.60–4.00%.     

Measurements of the thermal neutron cross-sections and resonance integrals for 186W (n,γ) 187W and 98Mo (n,γ) 99Mo reactions

The thermal neutron cross-sections and resonance integrals of the ¹⁸⁶W (n,γ) ¹⁸⁷W and ⁹⁸Mo (n,γ) ⁹⁹Mo reactions in the thermal and 1/E regions, respectively, of a thermal reactor neutron spectrum have been experimentally determined by the activation method using ¹⁹⁷Au (n,γ) ¹⁹⁸Au reaction as a single comparator. The high purity natural W, Mo, and Zr foils; and Au wire diluted in aluminum, were irradiated without Cd shield in two neutron irradiation sites, characterized with different values for the thermal-to-epithermal flux ratios, f at the Second Egyptian Research Reactor (ETRR-2). The induced activities in the samples were measured by high-resolution γ-ray spectrometry with a calibrated germanium detector. Thermal neutron cross-sections for 2200 m/s neutrons and resonance integrals for the ¹⁸⁶W (n,γ) ¹⁸⁷W and ⁹⁸Mo (n,γ) ⁹⁹Mo reactions have been obtained relative to the reference values, σ₀ = 98.65 ± 0.09 b and I ₀ = 1500 ± 28 b for the ¹⁹⁷Au (n,γ) ¹⁹⁸Au reaction. The necessary correction factors for thermal neutron and resonance neutron self-shielding effects, and the epithermal flux index (α) were taken into account in the determinations. The results obtained were: σ₀ = 38.43 ± 0.4 b and I ₀ = 502 ± 65 b for ¹⁸⁶W (n,γ) ¹⁸⁷W, and σ₀ = 0.137 ± 0.014 band I ₀ = 6.47 ± 0.8 for ⁹⁸Mo (n,γ) ⁹⁹Mo. These results are discussed and compared with previous measurements and evaluated data in literature. The traditional method of determining thermal cross-sections and resonance integrals via neutron irradiation with and without Cd shield in one irradiation position was avoided in this work by neutron irradiation without Cd shield in at least two different neutron irradiation positions. This method provides alternative way for determining thermal cross-sections and resonance integrals simultaneously.     

Influence of acid‐base dissociation equilibria during electromembrane extraction

Electromembrane extraction is affected by acid–base equilibria of the extracted substances as well as coupled equilibria associated with the partitioning of neutral substances to the supported liquid membrane. A theoretical model for this was developed and verified experimentally in the current work using pure 2‐nitrophenyl octyl ether as supported liquid membrane. From this model, extraction efficiency as a function of pH can be predicted. Substances with log P < 0–2 are generally extracted with low efficiency. Substances with log P > 2 are generally extracted with high efficiency when acceptor pH < pK_aH ? log P. Twelve basic drug substances (2.07 < log P < 6.57 and 6.03 < pK_aH < 10.47) were extracted under different pH conditions with 2‐nitrophenyl octyl ether as supported liquid membrane and fitted to the model. Seven of the drug substances behaved according to the model, while those with log P close to 2.0 deviated from prediction. The deviation was most probably caused by deprotonation and ion pairing within the supporting liquid membrane. Measured partition coefficients (log P) between 2‐nitrophenyl octyl ether and water, were similar to traditional log P values between n‐octanol and water. Thus, the latter have potential for pK_aH ? log P predictions.