A használatalapú biztosítás múltja, jelene és jövője

[Cp*RuCl]₄ (1) has previously been shown to be the precatalyst of choice for stereochemically unorthodox trans-hydrometalations of internal alkynes. Experimental and computational data now prove that the alkyne primarily acts as a four-electron donor ligand to the catalytically active metal fragment [Cp*RuCl] but switches to adopt a two-electron donor character once the reagent R₃MH (M = Si, Ge, Sn) enters the ligand sphere. In the stereodetermining step the resulting loaded complex evolves via an inner-sphere mechanism into a ruthenacyclopropene which swiftly transforms into the product. In accord with the low computed barriers, spectral and preparative data show that the reaction is not only possible but sometimes even favored at low temperatures. Importantly, such trans-hydrometalations are distinguished by excellent levels of regioselectivity when unsymmetrical alkynes are used that carry an −OH or −NHR group in vicinity of the triple bond. A nascent hydrogen bridge between the protic substituent and the polarized [Ru–Cl] unit imposes directionality onto the ligand sphere of the relevant intermediates, which ultimately accounts for the selective delivery of the R₃M– group to the acetylene C-atom proximal to the steering substituent. The interligand hydrogen bonding also allows site-selectivity to be harnessed in reactions of polyunsaturated compounds, since propargylic substrates bind more tightly than ordinary alkynes; even the electronically coupled triple bonds of conjugated 1,3-diynes can be faithfully discriminated as long as one of them is propargylic. Finally, properly positioned protic sites lead to a substantially increased substrate scope in that they render even 1,3-enynes, arylalkynes, and electron-rich alkynylated heterocycles amenable to trans-hydrometalation which are otherwise catalyst poisons

Formation of gold(III) alkyls from gold alkoxide complexes

The gold(III) methoxide complex (C^N^C)AuOMe 1 reacts with tris(p-tolyl)phosphine in benzene at room temperature under O-abstraction to give methylgold product (C^N^C)AuMe 2 together with O=P(p-tol)3 {(C^N^C) = [2,6-(C6H3tBu-4)2¬pyridine]2 }. Calculations show that this reaction is energetically favourable (ΔG = 32.3 kcal mol 1). The side-products in this reaction, the Au(II) complex [Au(C^N^C)]2 3 and the phosphorane (p-tol)3P(OMe)2, suggest that at least two reaction pathways may operate, including one involving (C^N^C)Au• radicals. Attempts to model the reaction by DFT methods showed that PPh3 can approach 1 to give a near-linear Au-O-P arrangement, without phosphine coordination to gold. The analogous reaction of (C^N^C)AuOEt, on the other hand, gives exclusively a mixture of 3 and (p-tol)3P(OEt)2. Whereas the reaction of (C^N^C)AuOR (R = But, p-C6H4F) with P(p-tol)3 proceeds over a period of hours, compounds with R = CH2CF3 or CH(CF3)2 react almost instantaneously, to give 3 and O=P(p-tol)3. In chlorinated solvents, treatment of the alkoxides (C^N^C)AuOR with phosphines generates [(C^N^C)Au(PR3)]Cl, via Cl-abstraction from the solvent. Attempts to extend the synthesis of gold(III) alkoxides to allyl alcohols were unsuccessful; the reaction of (C^N^C)AuOH with an excess of CH2=CHCH2OH in toluene led instead to allyl alcohol isomerization to give a mixture of gold alkyls, (C^N^C)AuR′ (R′ = -CH2CH2CHO 10 and CH2CH(CH2OH)¬OCH2¬CH=CH2 11), while 2-methallyl alcohol affords R′ = CH2CH(Me)CHO 12. The crystal structure of 11 was determined. The formation of Au-C instead of the expected Au-O products is in line with the trend in metal-ligand bond dissociation energies for Au(III), M-H > M-C > M-O

Replantation of different anatomical segments of the upper limb

CNŞPMU, Conferinţa Naţională în cadrul Asociaţiei Ortopezilor – Traumatologi din Republica Moldova ”Actualităţi în microchirurgia reconstructivă”, Chișinău, Republica MoldovaÎn lucrare sunt analizate 34 cazuri de replantare ale segmentelor amputate a membrului superior. În total au fost replantate: degete – 34 cazuri, segmentul mîinei la nivelul oaselor metacarpiene –2; la nivelul oaselor carpiene – 2, la nivelul articulaţiei pumnului – 1, segmentul treimii distale a antebraţului – 1. Replantarea au fost reuşite în 20 cazuri (64.7%).In this study 34 cases replantation of amputated segments at different levels were analyzed. In total there were replanted: fingers – 34 cases, the hand segment at the level of metacarpal bones –2 cases; at the level of carpal bones – 2 cases, at the level of the wrist joint – 1 case, at the distal one-third of the forearm – 1 case. Replantations were successful in 20 cases (64.7%)

Reactivity of Gold Hydrides: O2 Insertion into the Au–H Bond

Dioxygen reacts with the gold(I) hydride (IPr)AuH under insertion to give the hydroperoxide, (IPr)AuOOH, a long-postulated reaction in gold catalysis and the first demonstration of O2 activation by Au-H in a well-defined system. Subsequent condensation gave the peroxide (IPr)Au-OO-Au(IPr) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene). The reaction kinetics are reported, as well as the reactivity of Au(I) hydrides with radical scavengers

Вирусные гепатиты В, С и D в Республике Молдова: достижения и проблемы

Agenția Națională pentru Sănătate Publică, IP Universitatea de Stat de Medicină și Farmacie Nicolae Testemițanu, IMSP Centrul Republican de Diagnosticare MedicalăRealizarea primelor trei Programe Naționale de combatere a hepatitelor virale B, C și D în Republica Moldova, începând cu anul 1997, au condus la reducerea semnificativă a morbidității prin hepatitele virale B, C și D acute, dar pe fundalul incidenței sporite a hepatitelor virale cronice, unde indicatorii îi depășesc vădit pe cei din țările Comunității Europene. Studiile realizate demonstrează că contingentele de populație cu risc sporit de infectare continuă să prezinte un potențial înalt ca sursă reală de infectare cu virusurile hepatice nominalizate pentru alte categorii de populație. Ca urmare a utilizării tehnicilor de biologie moleculară, au fost evidențiate genotipurile și subgenotipurile virusurilor hepatitelor B, C și D în special la contingentele de populație cu risc sporit de infectare, demonstrând că unele posedă un potențial înalt de cronicizare, cu evoluție spre ciroză și cancer hepatocelular. Utilizarea produselor antivirale de ultimă generație recomandate de OMS pentru tratamentul hepatitelor virale B și C a demonstrat o eficacitate înaltă nu numai terapeutică, ci și profi lactică, manifestată prin reducerea numărului de bolnavi purtători de virusuri și a noilor focare. Este important de menționat că prejudiciul economic prevenit ca urmare a realizării Programelor Naționale de combatere a hepatitelor virale în perioada 1997-2015 a constituit 822.453 mii lei, pe când cheltuielile din bugetul de stat pentru realizarea acestor programe au alcătuit 84.618,5 mii lei. Realizarea integrală a prezentului Program de combatere a hepatitelor virale B, C și D în contextul Planului Strategic al OMS de eliminare a hepatitelor virale parenterale până în anul 2030 va avea un beneficiu socioeconomic extrem de important pentru Republica Moldova.The implementation of the first three National Programs against viral hepatitis B, C and D in the Republic of Moldova since 1997 has allowed to significantly reduce morbidity of acute viral hepatitis B, C and D, but on the increased background of incidence of chronic viral hepatitis the indicators clearly outweigh those in the European Community. Studies have shown that the contingent of population at high risk of infection continues to show a high potential as a real source of infection with viral hepatitis viruses for other population categories. As a result of the use of molecular biology techniques, the genotypes and subgenotypes of hepatitis B, C and D viruses have been highlighted, particularly in contingent of population at high risk of infection, demonstrating that some have a high potential for chronicization with progression to cirrhosis and hepatocellular cancer. Using of next-generation antiviral drugs in the treatment of viral hepatitis B and C recommended by the WHO has shown a high, not only therapeutic but also prophylactic efficacy manifested by reducing the number of virus-bearing patients, and new outbreaks. It is important to note that the economic prejudice prevented by the implementation of the National Programs against viral hepatitis during the period 1997-2015 amounted to 822.453 thousand lei, while the spending from the State Budget for the implementation of the nominated programs amounted to 84.618.5 thousand lei. The full implementation of the current Program for combating viral hepatitis B, C and D in the context of the WHO Strategic Plan for the elimination of parenteral viral hepatitis by 2030 will have a very important socio-economic benefit for the Republic of Moldova.Реализация первых трех Национальных программ по борьбе с вирусными гепатитами B, C и D в Республике Молдова с 1997 года позволила значительно снизить заболеваемость острыми вирусными гепатитами B, C и D, но на фоне высокого уровня заболеваемости хроническими вирусными гепатитами, показатели явно перевешивают показатели стран Европейского Cоюза. Исследования показали, что среди групп населения с высоким риском инфицирования все еще присутствует высокий потенциал в качестве реального источника заражения вирусами гепатитов для других категорий населения. В результате использования методов молекулярной биологии были выделены генотипы и субгенотипы вирусов гепатитов B, C и D, особенно среди групп с высоким риском инфицирования, демонстрируя, что некоторые имеют высокий потенциал к хронизации и прогрессированию к циррозу и гепатоцеллюлярного рака. Использование противовирусных препаратов последнего поколения для лечения вирусных гепатитов В, C и D, рекомендованных ВОЗ, продемонстрировало не только высокую терапевтическую, но и профилактическую эффективность за счет сокращения числа вирусоносителей и новых очагов инфекции. Важно отметить, что предотвращённый экономический ущерб в результате реализации Национальных программ по борьбе с вирусными гепатитами в период 1997–2015 годов составил 822.453 тысяч леев, а расходы государственного бюд-жета на реализацию указанных программ составили 84.618,5 тысяч леев. Полная реализация текущей Программы по борьбе с вирусными гепатитами B, C и D в контексте Стратегического плана ВОЗ по элиминации парентеральных вирусных гепатитов к 2030 году будет иметь важное социально-экономическое значение для Республики Молдова

Relating different Polynomial-LWE problems

In this paper we focus on Polynomial Learning with Errors (PLWE). This problem is parametrized by a polynomial and we are interested in relating the hardness of the $\text{PLWE}^f$ and $\text{PLWE}^h$ problems for different polynomials $f$ and $h$. More precisely, our main result shows that for a fixed monic polynomial $f$, $\text{PLWE}^{f\circ g}$ is at least as hard as $\text{PLWE}^f$, in both search and decision variants, for any monic polynomial $g$. As a consequence, $\text{PLWE}^{\phi_n}$ is harder than $\text{PLWE}^{f},$ for a minimal polynomial $f$ of an algebraic integer from the cyclotomic field $\mathbb{Q}(\zeta_n)$ with specific properties. Moreover, we prove in decision variant that in the case of power-of-2 polynomials, $\text{PLWE}^{\phi_n}$ is at least as hard as $\text{PLWE}^f,$ for a minimal polynomial $f$ of algebraic integers from the $n$th cyclotomic field with weaker specifications than those from the previous result

Lattice Trapdoors and IBE from Middle-Product LWE

Middle-product learning with errors (MP-LWE) was recently introduced by Rosca, Sakzad, Steinfeld and Stehlé (CRYPTO 2017) as a way to combine the efficiency of Ring-LWE with the more robust security guarantees of plain LWE. While Ring-LWE is at the heart of efficient lattice-based cryptosystems, it involves the choice of an underlying ring which is essentially arbitrary. In other words, the effect of this choice on the security of Ring-LWE is poorly understood. On the other hand, Rosca et al. showed that a new LWE variant, called MP-LWE, is as secure as Polynomial-LWE (another variant of Ring-LWE) over any of a broad class of number fields. They also demonstrated the usefulness of MP-LWE by constructing an MP-LWE based public-key encryption scheme whose efficiency is comparable to Ring-LWE based public-key encryption. In this work, we take this line of research further by showing how to construct Identity-Based Encryption (IBE) schemes that are secure under a variant of the MP-LWE assumption. Our IBE schemes match the efficiency of Ring-LWE based IBE, including a scheme in the random oracle model with keys and ciphertexts of size $\tilde{O}(n)$ (for $n$-bit identities). We construct our IBE scheme following the lattice trapdoors paradigm of [Gentry, Peikert, and Vaikuntanathan, STOC\u2708]; our main technical contributions are introducing a new leftover hash lemma and instantiating a new variant of lattice trapdoors compatible with MP-LWE. This work demonstrates that the efficiency/security tradeoff gains of MP-LWE can be extended beyond public-key encryption to more complex lattice-based primitives

Dispersion, solvent and metal effects in the binding of gold cations to alkynyl ligands: implications for Au(i) catalysis.

The coordination modes of the [Au(PPh3)](+) cation to metal alkynyl complexes have been investigated. On addition to ruthenium, a vinylidene complex, [Ru(η(5)-C5H5)(PPh3)2([double bond, length as m-dash]C[double bond, length as m-dash]CPh{AuPPh3})](+), is obtained while addition to a gold(iii) compound gives di- and trinuclear gold complexes depending on the conditions employed. In the trinuclear species, a gold(i) cation is sandwiched between two gold(iii) alkynyl complexes, suggesting that coordination of multiple C-C triple bonds to gold is facile

Structure from motion photogrammetry in forestry : a review

AbstractPurpose of ReviewThe adoption of Structure from Motion photogrammetry (SfM) is transforming the acquisition of three-dimensional (3D) remote sensing (RS) data in forestry. SfM photogrammetry enables surveys with little cost and technical expertise. We present the theoretical principles and practical considerations of this technology and show opportunities that SfM photogrammetry offers for forest practitioners and researchers.Recent FindingsOur examples of key research indicate the successful application of SfM photogrammetry in forestry, in an operational context and in research, delivering results that are comparable to LiDAR surveys. Reviewed studies have identified possibilities for the extraction of biophysical forest parameters from airborne and terrestrial SfM point clouds and derived 2D data in area-based approaches (ABA) and individual tree approaches. Additionally, increases in the spatial and spectral resolution of sensors available for SfM photogrammetry enable forest health assessment and monitoring. The presented research reveals that coherent 3D data and spectral information, as provided by the SfM workflow, promote opportunities to derive both structural and physiological attributes at the individual tree crown (ITC) as well as stand levels.SummaryWe highlight the potential of using unmanned aerial vehicles (UAVs) and consumer-grade cameras for terrestrial SfM-based surveys in forestry. Offering several spatial products from a single sensor, the SfM workflow enables foresters to collect their own fit-for-purpose RS data. With the broad availability of non-expert SfM software, we provide important practical considerations for the collection of quality input image data to enable successful photogrammetric surveys