Extending Fibre Nonlinear Interference Power Modelling to Account for General Dual-Polarisation 4D Modulation Formats

In optical communications, four-dimensional (4D) modulation formats encode information onto the quadrature components of two arbitrary orthogonal states of polarisation of the optical field. Many analytical models available in the optical communication literature allow, within a first-order perturbation framework, the computation of the average power of the nonlinear interference (NLI) accumulated in coherent fibre-optic transmission systems. However, all such models only operate under the assumption of transmitted polarisation-multiplexed two-dimensional (PM-2D) modulation formats, which only represent a limited subset of the possible dual-polarisation 4D (DP-4D) formats. Namely, only those where data transmitted on each polarisation channel are mutually independent and identically distributed. This paper presents a step-by-step mathematical derivation of the extension of existing NLI models to the class of arbitrary DP-4D modulation formats. In particular, the methodology adopted follows the one of the popular enhanced Gaussian noise model, albeit dropping most assumptions on the geometry and statistic of the transmitted 4D modulation format. The resulting expressions show that, whilst in the PM-2D case the NLI power depends only on different statistical high-order moments of each polarisation component, for a general DP-4D constellation, several other cross-polarisation correlations also need to be taken into account.     

Synthesis and Biological Activity of Some Trifluoromethyl Derivatives of 5-tert-Butyl-2-furylmethylideneanilines and Their Silyl Analogs

We have synthesized the corresponding aldimines by condensation of 5-tert-butylfurfural and its trimethyl- and triethylsilyl analogs with 2-, 3-, and 4-trifluoromethylanilines in the presence of 4 molecular sieves. We have studied their neurotropic and antitumor activity. The phenamine motor activity test showed that tert-butyl derivatives exhibit high efficacy and also shorten the ethanol narcosis time. Some silyl derivatives exhibit significant anti-corazole activity. The tert-butyl derivatives have high cytotoxicity toward human lung fibrosarcoma cells (the 3-trifluoromethyl-substituted derivative) and mouse hepatoma cells (the 2-trifluoromethyl-substituted derivative).     

Biophysical and Biological Tools to Better Characterize the Stability,Safety and Efficacy of a Cosmeceutical for Acne-Prone Skin

(1) Background: Acne is a widespread skin disease, especially among adolescents. Following the COVID-19 pandemic and the use of masks, the problem has been affecting a greater number of people, and the attention of the skin care beauty routine cosmetics has been focused on the “Maskne”, caused by the sebum excretion rate (SER) that stimulates microbial proliferation. (2) Methods: the present study was focused on the rheological characterization and quality assurance of the preservative system of an anti-acne serum. The biological effectiveness (cytotoxicity—skin and eye irritation—antimicrobial, biofilm eradication and anti-inflammatory activity) was evaluated in a monolayer cell line of keratinocytes (HaCaT) and on 3D models (reconstructed human epidermis, RHE and human reconstructed corneal epithelium, HCE). The Cutibacterium acnes, as the most relevant acne-inducing bacterium, is chosen as a pro-inflammatory stimulus and to evaluate the antimicrobial activity of the serum. (3) Results and Conclusions: Rheology allows to simulate serum behavior at rest, extrusion and application, so the serum could be defined as having a solid-like behavior and being pseudoplastic. The preservative system is in compliance with the criteria of the reference standard. Biological effectiveness evaluation shows non-cytotoxic and irritant behavior with a good antimicrobial and anti-inflammatory activity of the formulation, supporting the effectiveness of the serum for acne-prone skin treatment.     

Synthesis and neurotropic activity of silyl propargyl alcohols and sulfides

New silicon derivatives of hetaryl propargyl sulfides and propargyl alcohols were synthesized using phase‐transfer catalytic and organometallic methods. These compounds were tested for acute toxicity and neurotropic activity in the pentylenetetrazole test, and for phenamine hypothermia, phenamine hyperactivity and passive avoidance response tests. We have found that the silyl propargyl alcohols and sulfides are low toxicity compounds, the LD₅₀ being 700–1300 mg kg^?1. In the PAR test, the synthesized compounds exerted some memory‐improving activity. For di‐1‐(3‐methyl‐3‐hydroxybutyn‐1‐yl)methyl(3‐iodopropyl)silane ( 16 ) the effect was statistically significant and amounted to 250% of the control level. In the pentylenetetrazole test, all compounds possessed anticonvulsant activity, the most active compounds being 3‐(benzoxazolylthio)‐1‐propynyl(trimethyl)silane ( 6 ) and di‐[2‐(1‐hydroxycyclohexyl)ethynyl]methyl(3‐iodopropyl)silane ( 17 ). The phenamine‐induced hyperactivity was significantly elevated after treatment with (3‐trimethylsilyl‐2‐propynyl)thiobenzene ( 1 ) or di‐[1‐(3‐methyl‐3‐hydroxybutyn‐1‐yl)diphenylsilane ( 12 ). Our data show that these silicon derivatives of hetaryl propargyl sulfides and propargyl alcohols possess certain memory improving and anticonvulsant activity that should be studied in detail to evaluate the receptor systems involved. Copyright © 2004 John Wiley & Sons, Ltd.     

Diarylheptanoid-rich extract of grey and black alder barks: an effective dietary antioxidant in mayonnaise

Diarylheptanoid-rich extracts (DAHEs) isolated from grey and black alder bark with pressurized ethyl acetate were tested in mayonnaise as a dietary antioxidant using the Oxipres method. DAHE contains >700 mg g^?1 of oregonin possessing quite similar structure to the well-known dietary antioxidant curcumin, which is widely used as a bioactive constituent of food supplements. Strong radical scavenging capacity of oregonin was clearly demonstrated by the online HPLC–DPPH^? scavenging assay. The antioxidative effect of DAHEs in mayonnaise was dose dependent; however, even the lowest concentration (0.5 mg g^?1) of DAHE additive increased the induction period of oxidation more than two times. Consequently, DAHE may be considered as a promising natural antioxidant for commercial applications.     

Quantitative analysis of phenibut in rat brain tissue extracts by liquid chromatography–tandem mass spectrometry

Phenibut (3-phenyl-4-aminobutyric acid) is a γ-aminobutyric acid mimetic drug, which is used clinically as a mood elevator and tranquilizer. In the present work, a rapid, selective and sensitive liquid chromatography–tandem mass spectrometry method for quantification of phenibut in biological matrices has been developed. The method is based on protein precipitation with acidic acetonitrile followed by isocratic chromatographic separation using acetonitrile–formic acid (0.1% in water; 8:92, v/v) mobile phase on a reversed-phase column. Detection of the analyte was performed by electrospray ionization mass spectrometry in multiple reaction monitoring mode with the precursor-to-product ion transition m/z 180.3 → m/z 117.2. The calibration curve was linear over the concentration range 50–2000 ng/mL. The lower limit of quantification for phenibut in rat brain extracts was 50 ng/mL. Acceptable precision and accuracy were obtained over the whole concentration range. The validated method was successfully applied in a pharmacological study to analyze phenibut concentration in rat brain tissue extract samples. Copyright © 2008 John Wiley & Sons, Ltd.     

Novel methods for the synthesis of 2-[(4<Emphasis Type="Italic">R</Emphasis>)-2-oxo-4-phenylpyrrolidin-1-yl]-acetamide ((<Emphasis Type="Italic">R</Emphasis>)-phenotropil)

Two novel methods have been developed for the preparation of 2-[(4R)-2-oxo-4-phenylpyrrolidin-1-yl]acetamide ((R)-Phenotropil). In the first, n-butyl (3R)-4-amino-3-phenylbutyrate is alkylated with haloacetamide in DMF in the presence of potassium phosphate monohydrate, and the intermediate 4-carbamoylmethylamino-3-phenylbutyrate is subsequently cyclized by refluxing in toluene in the presence of potassium phosphate monohydrate and tetrabutylammonium bromide. In the second, chloroacetonitrile is used under similar conditions in place of the haloacetamide. Both methods lead to (R)-Phenotropil in 40-60% yields calculated on the starting n-butyl (3R)-4-amino-3-phenylbutyrate.