Twin-photon techniques for photo-detector calibration

The aim of this review paper is to enlighten some recent progresses in quantum optical metrology in the part of quantum efficiency measurements of photo-detectors performed with bi-photon states. The intrinsic correlated nature of entangled photons from Spontaneous Parametric Down Conversion phenomenon has opened wide horizons to a new approach for the absolute measurement of photo-detector quantum efficiency, outgoing the requirement for conventional standards of optical radiation; in particular the simultaneous feature of the creation of conjugated photons led to a well known technique of coincidence measurement, deeply understood and implemented for standard uses. On the other hand, based on manipulation of entanglement developed for Quantum Information protocols implementations, a new method has been proposed for quantum efficiency measurement, exploiting polarisation entanglement in addition to energy-momentum and time ones, that is based on conditioned polarisation state manipulation. In this review, after a general discussion on absolute photo-detector calibration, we compare these different methods, in order to give an accurate operational sketch of the absolute quantum efficiency measurement state of the art

Interferometric Bell-state preparation using femtosecond-pulse-pumped Spontaneous Parametric Down-Conversion

We present theoretical and experimental study of preparing maximally entangled two-photon polarization states, or Bell states, using femtosecond pulse pumped spontaneous parametric down-conversion (SPDC). First, we show how the inherent distinguishability in femtosecond pulse pumped type-II SPDC can be removed by using an interferometric technique without spectral and amplitude post-selection. We then analyze the recently introduced Bell state preparation scheme using type-I SPDC. Theoretically, both methods offer the same results, however, type-I SPDC provides experimentally superior methods of preparing Bell states in femtosecond pulse pumped SPDC. Such a pulsed source of highly entangled photon pairs is useful in quantum communications, quantum cryptography, quantum teleportation, etc.Comment: 11 pages, two-column format, to appear in PR

Side effects of psychotropic drugs on eye

A.A. Petukhova1, A.A. Panov1, Ya.V. Malygin2, M.A. Kazanfarova3 1Lomonosov Moscow State University, Moscow, Russian Federation 2A.I. Evdokimov Moscow University of Medicine and Dentistry, Moscow, Russian Federation 3Skolkovo Innovation Center, Moscow Region, Russian Federation Any antipsychotics provoke more or less ocular complications. Some of them are relatively harmless (i.e., dark eyelids, conjunctival and corneal pigmentation, mydriasis, nystagmus, dry eye etc.). These adverse effects are resolved spontaneously after treatment discontinuation, drug switching, or prescribing additional therapy. However, the intake of both typical and atypical neuroleptics, lithium salts, some anticonvulsants (e.g., topiramate) is associated with high risks of vision loss. Moreover, in some patients these medications may result in blindness. The use of psychotropic drugs (e.g., tricyclic antidepressants or serotonin reuptake inhibitors) in patients with higher risk of acute angle closure is of particular concern. The association between phenothiazines and anticonvulsants and retinopathy, chlorpromazine and cataract, anticonvulsants and poor color vision and reduced contrast sensitivity is also important. Psychiatrists and ophthalmologists should consider potenti al ocular side effects in patients receiving psychotropic drugs. Knowing management algorithm for these conditions is also important. The number of recent publications on this issue is limited. Therefore, articles older than 10 years are sometimes used. Keywords: eye, visual organ, adverse effects, psychotropic drugs, neuroleptics, tricyclic antidepressants, selective serotonin reuptake inhibitors, glaucoma, retinopathy, cataract. For citation: Petukhova A.A., Panov A.A., Malygin Ya.V., Kazanfarova M.A. Side effects of psychotropic drugs on eye. Russian Journal of&nbsp;Clinical Ophthalmology. 2021;21(1):29–33. DOI: 10.32364/2311-7729-2021-21-1-29-33. <br

Methanol oxidative dehydrogenation on nanostructured vanadium-containing composite membranes

The nanostructured composite catalytic membranes were prepared in situ in a membrane reactor by the molecular layering method (ML) of V-O and V-O-P catalytic structures deposition. The test operation of the membrane reactor was carried out for the oxidative dehydrogenation of methanol at two modes of reagents supply to a catalytic layer: at methanol diffusion through the membrane (MR-M) or at oxygen diffusion through the membrane (MR-O). The MR-M mode provided higher methanol conversion and selectivity by formaldehyde than the MR-O mode at introduction of methanol and oxygen by co-current flow. The V-O and V-O-P catalytic structures showed the different behavior depending on the mode of supply of methanol and oxygen to the catalytic layer. © 2007 Elsevier B.V. All rights reserved. 10.1016/j.memsci.2007.06.03

Molecular environment of the IIId subdomain of the IRES element of hepatitits C virus RNA on the human 40S ribosomal subunit

The molecular environment of the key subdomain IIId of the internal ribosome entry site (IRES) element of hepatitis C virus (HCV) RNA in the binary complex with the human 40S ribosomal subunit was studied. To this end, HCV IRES derivatives bearing perfluorophenylazido groups activatable by mild UV at nucleotides G263 or A275 in the subdomain IIId stem were used. They were prepared by the complementary addressed modification of the corresponding RNA transcript with alkylating oligodeoxyribonucleotide derivatives. None of the RNA derivatives were shown to be crosslinked to the 18S rRNA. It was found that the photoreactive groups of the IRES G263 and A275 nucleotides are crosslinked to ribosomal proteins S3a, S14, and S16. For the IRES derivative with the photoreactive group in nucleotide G263, the degree of modification of proteins S14 and S16 was greater than that of S3a, whereas the derivative containing the same photoreactive group in nucleotide A275 was mainly crosslinked to proteins S3a and S14. An analysis of the data led to the conclusion that in the binary complex of HCV IRES elements with the small subunit of the 80S ribosome, its subdomain IIId stem is located on the solvent side of the subunit between the head and the body next to the "beak" near the exit of mRNA from the ribosome

Molecular contacts of ribose-phosphate backbone of mRNA with human ribosome

In this work, intimate contacts of riboses of mRNA stretch from nucleotides in positions +3 to +12 with respect to the first nucleotide of the P site codon were studied using cross-linking of short mRNA analogs with oxidized 3'-terminal riboses bound to human ribosomes in the complexes stabilized by codon-anticodon interactions and in the binary complexes. It was shown that in all types of complexes cross-links of the mRNA analogs to ribosomal protein (rp) uS3 occur and the yield of these cross-links does not depend on the presence of tRNA and on sequences of the mRNA analogs. Site of the mRNA analogs cross-linking in rp uS3 was mapped to the peptide in positions 55-64 that is located away from the mRNA binding site. Additionally, in complexes with P site-bound tRNA, riboses of mRNA nucleotides in positions +4 to +7 cross-linked to the C-terminal tail of rp uS19 displaying a contact specific to the decoding site of the mammalian ribosome, and tRNA bound at the A site completely blocked this cross-linking. Remarkably, rps uS3 and uS19 were also able to cross-link to the fragment of HCV IRES containing unstructured 3'-terminal part restricted by the AUGC tetraplet with oxidized 3'-terminal ribose. However, no cross-linking to rp uS3 was observed in the 48S preinitiation complex assembled in reticulocyte lysate with this HCV IRES derivative. The results obtained show an ability of rp uS3 to interact with single-stranded RNAs. Possible roles of rp uS3 region 55-64 in the functioning of ribosomes are discussed