DTR-SHIELD: Mutual Synchronization for Protecting against DoS Attacks on the SHIELD Protocol with AES-CTR Mode.

To enhance security in the semiconductor industry's globalized production, the Defense Advanced Research Projects Agency (DARPA) proposed an authentication protocol under the Supply Chain Hardware Integrity for Electronics Defense (SHIELD) program. This protocol integrates a secure hardware root-of-trust, known as a dielet, into integrated circuits (ICs). The SHIELD protocol, combined with the Advanced Encryption Standard (AES) in counter mode, named CTR-SHIELD, targets try-and-check attacks. However, CTR-SHIELD is vulnerable to desynchronization attacks on its counter blocks. To counteract this, we introduce the DTR-SHIELD protocol, where DTR stands for double counters. DTR-SHIELD addresses the desynchronization issue by altering the counter incrementation process, which previously solely relied on truncated serial IDs. Our protocol adds a new AES encryption step and requires the dielet to transmit an additional 100 bits, ensuring more robust security through active server involvement and message verification.

A multicenter, randomized, open-labelled, non-inferiority trial of sustained-release sarpogrelate versus clopidogrel after femoropopliteal artery intervention.

Optimal antiplatelet therapy after endovascular therapy (EVT) for peripheral artery disease is controversial. This trial aimed to evaluate whether sarpogrelate plus aspirin was non-inferior for preventing early restenosis after femoropopliteal (FP) EVT compared to clopidogrel plus aspirin. In this open-label, prospective randomized trial, 272 patients were enrolled after successful EVT for FP lesions. Patients in each group received aspirin 100 mg and clopidogrel 75 mg or sarpogrelate 300 mg orally once per day for 6 months. The primary outcome was target lesion restenosis at 6 months, tested for noninferiority. Patient characteristics and EVT patterns were similar, except for increased inflow procedures in the sarpogrelate group and increased outflow procedures in the clopidogrel group. The sarpogrelate group showed a tendency of less restenosis at 6 months than the clopidogrel group (13.0% vs. 19.1%, difference 6.1 percentage points, 95% CI for noninferiority - 0.047 to 0.169). Secondary endpoints related to safety outcomes were rare in both groups. Risks of target lesion restenosis of the two intervention arm were uniform across most major subgroups except for those with coronary artery disease. In conclusion, Sarpogrelate plus aspirin is non-inferior to clopidogrel plus aspirin in preventing early restenosis after FP EVT. Larger multi-ethnic trials are required to generalize these findings. Trial registration: National Institutes of Health Clinical Trials Registry (ClinicalTrials.gov identifier: NCT02959606; 09/11/2016).

Multi-Walled Carbon Nanotube-Assisted Encapsulation Approach for Stable Perovskite Solar Cells.

Perovskite solar cells (PSCs) are regarded as the next-generation thin-film energy harvester, owing to their high performance. However, there is a lack of studies on their encapsulation technology, which is critical for resolving their shortcomings, such as their degradation by oxygen and moisture. It is determined that the moisture intrusion and the heat trapped within the encapsulating cover glass of PSCs influenced the operating stability of the devices. Therefore, we improved the moisture and oxygen barrier ability and heat releasing capability in the passivation of PSCs by adding multi-walled carbon nanotubes to the epoxy resin used for encapsulation. The 0.5 wt% of carbon nanotube-added resin-based encapsulated PSCs exhibited a more stable operation with a ca. 30% efficiency decrease compared to the ca. 63% decrease in the reference devices over one week under continuous operation. Specifically, the short-circuit current density and the fill factor, which are affected by moisture and oxygen-driven degradation, as well as the open-circuit voltage, which is affected by thermal damage, were higher for the multi-walled carbon nanotube-added encapsulated devices than the control devices, after the stability test.

Safety and feasibility of 3-month interval access and flushing for maintenance of totally implantable central venous port system in colorectal cancer patients after completion of curative intended treatments.

ABSTRACT: Patients with colorectal cancer (CRC) treated with curative intent surgery undergo continuous fluorouracil (5-FU) infusion-based chemotherapy using totally implantable central venous port system (TICVPS) in cases with high risk of recurrence. Approximately 30% of patients relapse after therapy completion, especially within 2 years. Hence, many patients with high risk CRC keep the TICVPS for 6 to 24 months after treatment with regular intervals of TICVPS flushing. However, little is known about the proper interval duration of the port. The aim of this study is to investigate whether a 3 months extended interval is safe and if port maintenance is feasible.A retrospective cohort was compiled of patients with CRC who underwent curative intent surgery and perioperative chemotherapy using TICVPS between 2010 and 2017. The primary end point was TICVPS maintenance rate, including maintenance of TICVPS for at least 6 months, planned TICVPS removal after 6 months, and regaining the use of TICVPS at the time of recurrence.A total of 214 patients with CRC underwent curative intent treatments during the study period. Among them, 60 patients were excluded, including 6 patients for early recurrence within 3 months and 54 patients with violation of flushing interval. Finally, 154 patients were analyzed. Mean flushing interval was 98.4 days (95% confidence interval [CI], 96.2-100.6; range, 60-120). In December 2018, 35 patients kept the TICVPS, 92 patients had planned removal, 25 patients reused the TICVPS, and 2 patients had to unexpectedly remove the TICVPS due to site infection and pain. Thus, the functional TICVPS maintenance rate was 98.8% (152/154). Thirty-eight patients relapsed, and 30 patients were treated with intravenous chemotherapy. Among them, 25 patients (83.3%) reused the maintained TICVPS without a reinsertion procedures.Our study demonstrated that 3-month interval access and flushing is safe and feasible for maintaining TICVPS during surveillance of patients with CRC. An extended interval up to 3 months can be considered because it is compatible with CRC surveillance visit schedules.

Carbon Nanotube Mask Filters and Their Hydrophobic Barrier and Hyperthermic Antiviral Effects on SARS-CoV-2.

Carbon nanotube face mask filters have strong and uniform hydrophobicity, high durability, and high thermal conductivity and exhibit excellent barrier and antiviral effects against SARS-CoV-2. The nanocarbon filter functions as a superior barrier compared to those in conventional masks owing to the stronger, more uniform, and more durable hydrophobic nature of the carbon nanotubes. A tightly knit carbon nanotube network has a pore size smaller than that of the average coronavirus; nevertheless, the breathability is equal to that of the conventional polypropylene filter. The exceptional thermal conductivity of carbon nanotubes transpires hyperthermic antiviral effects, which offers stronger protection against the virus, as well as reusability. The facile processability, low cost, and light weight of the aerosol-synthesized carbon nanotube filter warrants its viability, reinforcing the fight against the COVID-19 pandemic.

Azabuckybowl-Based Molecular Tweezers as C60 and C70 Receptors.

We designed and synthesized molecular tweezers consisting of nitrogen-embedded buckybowl subunits. The judicious choice of the covalent linkers modulated their binding strength with C60 or C70 in solution. Titration studies by optical and 1H NMR analyses revealed a 1:1 composition of the resulting complexes. X-ray diffraction analysis elucidated their solid-state structures, in which two azabuckybowl units surround one fullerene molecule. The large association constants stabilize the complexes toward redox reactions and the purification process on silica-gel column chromatography. The linker enabled tuning of the cavity size for binding of fullerenes, achieving complementary fullerene hosts for C60 and C70: the carbazole-bridged dimer preferentially associates with C70 over C60, while the phenanthrene-bridged dimer interacts with C60 more strongly than C70. Electrochemical analysis in combination with density functional theory calculations indicated the existence of intermolecular charge-transfer interactions between the buckybowl units and the fullerenes. Nonlinear optical measurements showed that the two-photon absorption cross sections of the molecular tweezers are enhanced upon association with fullerenes.

Benzonorcorrole NiII Complexes: Enhancement of Paratropic Ring Current and Singlet Diradical Character by Benzo-Fusion.

Fused benzene rings to antiaromatic compounds generally improve their stability but attenuate their antiaromaticity. The opposite case is now reported. NiII benzonorcorroles were synthesized and the effect of benzo-fusion on the antiaromaticity was elucidated. The benzo-fusion resulted in significant decrease of the HOMO-LUMO gaps and enhancement of the paratropic ring current effect. Furthermore, the introduction of the benzo groups induced singlet diradical character in the antiaromatic porphyrinoid.

Bicyclic Baird-type aromaticity.

Classic formulations of aromaticity have long been associated with topologically planar conjugated macrocyclic systems. The theoretical possibility of so-called bicycloaromaticity was noted early on. However, it has yet to be demonstrated by experiment in a simple synthetic organic molecule. Conjugated organic systems are attractive for studying the effect of structure on electronic features. This is because, in principle, they can be modified readily through dedicated synthesis. As such, they can provide useful frameworks for testing by experiment with fundamental insights provided by theory. Here we detail the synthesis and characterization of two purely organic non-planar dithienothiophene-bridged [34]octaphyrins that permit access to two different aromatic forms as a function of the oxidation state. In their neutral forms, these congeneric systems contain competing 26 and 34 π-electronic circuits. When subject to two-electron oxidation, electronically mixed [4n+1]/[4n+1] triplet biradical species in the ground state are obtained that display global aromaticity in accord with Baird's rule.

Fluorenyl Based Macrocyclic Polyradicaloids.

Synthesis of stable open-shell polyradicaloids including control of intramolecular spin-spin interactions is a challenging topic in organic chemistry and materials science. Herein, we report the synthesis and physical characterization of two series of fluorenyl based macrocyclic polyradicaloids. In one series (FR-MCn, n = 4-6), the fluorenyl radicals are directly linked at 3,6-positions; whereas in the other series (MC-FnAn, n = 3-5), an additional ethynylene moiety is inserted between the neighboring fluorenyl units. To access stable macrocyclic polyradicaloids, three synthetic methods were developed. All of these stable macrocycles can be purified by normal silica gel column chromatography under ambient conditions. In all cases, moderate polyradical characters were calculated by restricted active space spin-flip method due to the moderate intramolecular antiferromagnetic spin-spin interactions. The excitation energies from the low-spin ground state to the lowest high-spin excited state were evaluated by superconducting quantum interference device measurements. Their physical properties were also compared with the respective linear fluorenyl radical oligomers (FR-n, n = 3-6). It is found that the geometry, i.e., the distortional angle and spacer (w or w/o ethynylene) between the neighboring fluorenyl units, has significant effect on their polyradical character, excitation energy, one-photon absorption, two-photon absorption and electrochemical properties. In addition, the macrocyclic tetramers FR-MC4 and MC-F4A4 showed global antiaromatic character due to cyclic π-conjugation with 36 and 44 π-electrons, respectively.

Structural, Photophysical, and Magnetic Circular Dichroism Studies of Three Rigidified meso-Pentafluorophenyl-Substituted Hexaphyrin Analogues.

Detailed electronic, structural, photophysical, and redox studies of a series of meso-pentafluorophenyl-substituted hexaphyrins, namely amethyrin (1), rosarin (2), and rubyrin (3), are described. In prior work, it was found that the electronic states of the antiaromatic hexapyrrolic macrocycle, [24]rosarin 2, could be modified by exposure to several Brønsted acids (e.g., HCl, HBr and HI) to produce either one- and two-electron reduced species, or both. In an effort to gain further insights into the reactivity of hexaphyrins possessing different π-conjugation pathways, the ß-dodecamethyl-substituted [24]amethyrin 1 was prepared and its electronic structure was analyzed along with that of the o-phenylene-bridged [26]rubyrin 3 and rosarin 2 The [4n] and [4n+2] π-conjugated formulations of 2 and 3, respectively, were inferred from steady-state, fs-transient absorption and two photon absorption measurements. Similar photophysical analyses lead to the conclusion that 1 is best considered as nonaromatic or weakly antiaromatic. Magnetic circular dichroism (MCD) spectroscopic analyses of hexaphyrins 1 and 3, as well as comparisons to 2, and theoretical perimeter MO diagram analyses provided support for the electronic assignments. In contrast to what was found for 2, simple protonation of 1 and 3 by halohydric acids did not induce an evident, redox-based change in the electronic structure of the macrocycle.

Electron Transfer from Triplet State of TIPS-Pentacene Generated by Singlet Fission Processes to CH3NH3PbI3 Perovskite.

To reveal the applicability of singlet fission processes in perovskite solar cell, we investigated electron transfer from TIPS-pentacene to CH3NH3PbI3 (MAPbI3) perovskite in film phase. Through the observation of the shorter fluorescence lifetime in TIPS-pentacene/MAPbI3 perovskite bilayer film (5 ns) compared with pristine MAPbI3 perovskite film (20 ns), we verified electron-transfer processes between TIPS-pentacene and MAPbI3 perovskite. Furthermore, the observation of singlet fission processes, a faster decay rate, TIPS-pentacene cations, and the analysis of kinetic profiles of the intensity ratio between 500 and 525 nm in the TA spectra of the TIPS-pentacene/MAPbI3 perovskite bilayer film indicate that electron transfer occurs from triplet state of TIPS-pentacene generated by singlet fission processes to MAPbI3 perovskite conduction band. We believe that our results can provide useful information on the design of solar cells sensitized by singlet fission processes and pave the way for new types of perovskite solar cells.

Radical and Diradical Formation in Naphthalene Diimides through Simple Chemical Oxidation.

We successfully synthesized, for the first time, a naphthalene diimide (NDI) radical and diradical by simple chemical oxidation using lead(IV) dioxide. The formation of the (di)radical is confirmed by UV/Vis/NIR absorption, 1 H NMR, and electron paramagnetic resonance (EPR) measurements. In particular, temperature-dependent EPR, SQUID (superconducting quantum interference device) measurements, and quantum calculations demonstrated that the generated NDI diradical has a singlet diradical character of y=0.69 in the ground state. Subsequent characterization of this (di)radical revealed its stabilities, large two-photon absorption cross-section, and short excited-state lifetime.

Krill Oil Supplementation Improves Dyslipidemia and Lowers Body Weight in Mice Fed a High-Fat Diet Through Activation of AMP-Activated Protein Kinase.

Krill oil is a novel, commercially available marine oil rich in long-chain polyunsaturated omega-3 fatty acids, particularly eicosapentaenoic acid and docosahexaenoic acid. Compared with fish oil, the effects of krill oil supplementation on human health and its underlying action mechanisms are currently poorly understood. In the present study, we examined the effect of krill oil supplementation on metabolic parameters of mice fed a high-fat diet (HFD). Krill oil supplementation in mice fed a HFD for 10 weeks resulted in an ∼15% lower body weight gain and a dramatic suppression of hepatic steatosis. These effects were associated with significantly lower serum triglyceride and low-density lipoprotein-cholesterol levels. We further uncovered a novel underlying mechanism, showing that AMP-activated protein kinase, a master regulator of glucose and lipid metabolism, mediates the beneficial effects of krill oil.

Symmetry-Dependent Intramolecular Charge Transfer Dynamics of Pyrene Derivatives Investigated by Two-Photon Excitation.

Intramolecular charge transfer (ICT) processes in two-photon (TP) allowed states were investigated using three pyrene derivatives N1, N2C, and N2T, which have different molecular symmetry depending on the number and position of N,N-dimethylaniline donating substituents. On the basis of steady-state and nondegenerate two-photon absorption measurements, we investigated femtosecond transient absorption (TA) spectra by one-photon (OPE) and two-photon excitation (TPE). In the analysis of TA spectra, we discovered that the transfer rate from locally excited state to the ICT state by TPE is slower than that by OPE, indicating that the energy barrier between the TP and ICT states is higher than that between the one-photon (OP) allowed and ICT states. Furthermore, we demonstrated that ICT dynamics in a TP state are affected by molecular symmetry through the disappearance of stimulated emission from the locally excited state in the TA spectra of N2T obtained by TPE. We believe that our findings will provide fundamental information for a better understanding of excited-state ICT dynamics.

Stable 3,6-Linked Fluorenyl Radical Oligomers with Intramolecular Antiferromagnetic Coupling and Polyradical Characters.

Organic radicals display unique physical structures and could become next generation functional materials. However, design and synthesis of stable neutral radicals with a significant polyradical character has been an enormous challenge for chemists. In this work, we synthesized a series of stable 3,6-linked, kinetically blocked fluorenyl radical oligomers up to hexamer (FR-n, n = 1-6). Their ground-state geometric and electronic structures were systematically studied by various experimental methods including X-ray crystallographic analysis, variable temperature nuclear magnetic resonance, electron spin resonance, and superconducting quantum interference device measurements, supported by density functional theory and ab initio calculations. Moderate antiferromagnetic coupling between the fluorenyl radicals was observed, and moderate to large diradical and polyradical characters were calculated from dimer onward. Furthermore, their photophysical properties were estimated by steady-state, transient absorption, and two-photon absorption measurements, and their electrochemical properties were investigated by cyclic voltammetry/differential pulse voltammetry and spectro-electrochemical measurements. A clear chain length dependence of their optical, electrochemical, and magnetic properties was found for the oligomers with an odd or even number of spin centers, respectively.

Multifaceted [36]octaphyrin(1.1.1.1.1.1.1.1): deprotonation-induced switching among nonaromatic, Möbius aromatic, and Hückel antiaromatic species.

Deprotonation of nonaromatic octakis-(pentafluorophenyl)-substituted [36]octaphyrin(1.1.1.1.1.1.1.1) with tetrabutylammonium fluoride (TBAF) afforded monoanionic twisted Möbius aromatic species and dianinonic square Hückel antiaromatic species, depending upon the amount of TBAF.

Octazethrene and Its Isomer with Different Diradical Characters and Chemical Reactivity: The Role of the Bridge Structure.

The fundamental relationship between structure and diradical character is important for the development of open-shell diradicaloid-based materials. In this work, we synthesized two structural isomers bearing a 2,6-naphthoquinodimethane or a 1,5-naphthoquinodimethane bridge and demonstrated that their diradical characters and chemical reactivity are quite different. The mesityl-or pentafluorophenyl-substituted octazethrene derivatives OZ-M/OZ-F and their isomer OZI-M (with mesityl substituents) were synthesized via an intramolecular Friedel-Crafts alkylation followed by oxidative dehydrogenation strategy from the key building blocks 4 and 11. Our detailed experimental and theoretical studies showed that both isomers have an open-shell singlet ground state with a remarkable diradical character (y0 = 0.35 and 0.34 for OZ-M and OZ-F, and y0 = 0.58 for OZI-M). Compounds OZ-M and OZ-F have good stability in an ambient environment, while OZI-M has high reactivity and can be easily oxidized to a dioxo product 15, which can be correlated to their different diradical characters. Additionally, we investigated the physical properties of OZ-M, OZ-F, and 15.

A very rapid electronic relaxation process in a highly conjugated Zn(II)porphyrin-[26]hexaphyrin-Zn(II)porphyrin hybrid tape.

The excited-state energy relaxation processes of a Zn(II)porphyrin­[26]hexaphyrin­Zn(II)porphyrin triply linked hybrid tape, FZn, have been investigated by femtosecond transient absorption spectroscopy (TA), using a directly meso­meso linked hybrid trimer, HZn, as a reference compound. FZn has a very small S1­S0 energy gap through the expansion of π-conjugation and the absorption band at 1897 nm corresponds to its lowest singlet excited-state as a consequence of enhanced transition dipole moment that lies parallel to the long molecular axis. In TA measurements, we observe an energy transfer process (0.4 ps) from the Zn(II)porphyrin moiety to the [26]hexaphyrin core in HZn. In contrast to HZn, a biexponential decay with the time constants of 0.25 and 6.5 ps was observed in the decay profile of FZn. The detailed analysis of excitation wavelength, temperature and solvent dependent TA in FZn revealed that the electronic relaxation process (0.25 ps) from S1 to S0 is faster than the vibrational relaxation processes (5.9 ps) in the excited and ground states due to a very small S1­S0 energy gap through the expansion of π-conjugation. Accordingly, we demonstrate that electronic deactivation overtakes vibrational relaxation processes in a highly conjugated FZn.

A Diradical Approach towards BODIPY-Based Dyes with Intense Near-Infrared Absorption around λ=1100†nm.

A diradical approach to obtain stable organic dyes with intense absorption around λ=1100 nm is reported. The para- and meta-quinodimethane-bridged BODIPY dimers BD-1 and BD-2 were synthesized and were found to have a small amount of diradical character. These molecules exhibited very intense absorption at λ=1088 nm (ɛ=6.65×10(5)  M(-1) cm(-1) ) and 1136 nm (ɛ=6.44×10(5)  M(-1) cm(-1) ), respectively, together with large two-photon-absorption cross-sections. Structural isomerization induced little variation in their diradical character but distinctive differences in their physical properties. Moreover, the compounds showed a selective fluorescence turn-on response in the presence of the hydroxyl radical but not with other reactive oxygen species.