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Messenger RNA (mRNA) vaccine development for preventive and therapeutic applications has evolved rapidly over the last decade. The mRVNA vaccine has proven therapeutic efficacy in various applications, including infectious disease, immunotherapy, genetic disorders, regenerative medicine, and cancer. Many mRNA vaccines have made it to clinical trials, and a couple have obtained FDA approval. This emerging therapeutic approach has several advantages over conventional methods: safety; efficacy; adaptability; bulk production; and cost-effectiveness. However, it is worth mentioning that the delivery to the target site and in vivo degradation and thermal stability are boundaries that can alter their efficacy and outcomes. In this review, we shed light on different types of mRNA vaccines, their mode of action, and the process to optimize their development and overcome their limitations. We also have explored various delivery systems focusing on the nanoparticle-mediated delivery of the mRNA vaccine. Generally, the delivery system plays a vital role in enhancing mRNA vaccine stability, biocompatibility, and homing to the desired cells and tissues. In addition to their function as a delivery vehicle, they serve as a compartment that shields and protects the mRNA molecules against physical, chemical, and biological activities that can alter their efficiency. Finally, we focused on the future considerations that should be attained for safer and more efficient mRNA application underlining the advantages and disadvantages of the current mRNA vaccines. [ABSTRACT FROM AUTHOR]

The comment has corrected highly debatable information, in which we claimed that the SA binds only to the hemagglutinin proteins rather than the S protein, especially for SARS-CoV-2 and MERS-CoV. The hemagglutinin is known as the main envelop glycoprotein of influenza B virus, inducing receptor binding, while neuraminidase works as a separate glycoprotein. Sialic acid (SA) is the glycoprotein that is densely projected on the surface of different mammalian cells including lung epithelial cells. Development of a Colorimetric Tool for SARS-CoV-2 and Other Respiratory Viruses Detection Using Sialic Acid Fabricated Gold Nanoparticles. [Extracted from the article]

Sialic acid that presents on the surface of lung epithelial cells is considered as one of the main binding targets for many respiratory viruses, including influenza and the current coronavirus (SARS-CoV-2) through the viral surface protein hemagglutinin. Gold nanoparticles (Au NPs) are extensively used in the diagnostic field owing to a phenomenon known as 'surface plasmonic resonance' in which the scattered light is absorbed by these NPs and can be detected via UV-Vis spectrophotometry. Consequently, sialic acid conjugated Au NPs (SA-Au NPs) were utilized for their plasmonic effect against SARS-CoV-2, influenza B virus, and Middle-East respiratory syndrome-related coronavirus (MERS) in patients' swab samples. The SA-Au NPs system was prepared by a one-pot synthesis method, through which the NPs solution color changed from pale yellow to dark red wine color, indicting its successful preparation. In addition, the SA-Au NPs had an average particle size of 30 ± 1 nm, negative zeta potential (−30 ± 0.3 mV), and a UV absorbance of 525 nm. These NPs have proven their ability to change the color of the NPs solutions and patients' swabs that contain SARS-CoV-2, influenza B, and MERS viruses, suggesting a rapid and straightforward detection tool that would reduce the spread of these viral infections and accelerate the therapeutic intervention. [ABSTRACT FROM AUTHOR]

Simple Summary: Aedes aegypti is a mosquito that is responsible for spreading viral diseases including dengue fever, Zika, and chikungunya. Disease spread can be reduced by releasing mosquitoes containing bacteria known as Wolbachia, which inhibit transmission. Before such releases, it is important to collect data about where Ae. aegypti occur in urban landscapes and how populations vary over space and time. In this study, we present a pre-release analysis of mosquito populations using ovitraps (traps that provide a substrate for female mosquitoes to lay eggs), in Jeddah, Saudi Arabia. Our study contains a number of important findings. Firstly, we showed that there was no difference in the numbers of eggs laid between basement and non-basement locations. Secondly, we showed that, for some study sites, there was significant spatial structure to populations, meaning that where numbers of eggs were high (or low) they tended to remain high (or low) on average for many hundreds of meters. We also found that when mosquitoes are present in an area during the dry season, they tend to remain into the wet season; however, regions of high egg production could change between seasons. This suggests that in Jeddah's arid environment, the quality of breeding environments is inconsistent over time. Releases of Aedes aegypti carrying Wolbachia bacteria are known to suppress arbovirus transmission and reduce the incidence of vector-borne diseases. In planning for Wolbachia releases in the arid environment of Jeddah, Saudi Arabia, we collected entomological data with ovitraps across a 7-month period in four locations. Herein, we show that mosquito presence in basements does not differ from that of non-basement areas of buildings. In modelling mosquito presence across the study sites, we found the spatial structure to be statistically significant in one of the four sites, while a significant spatial structure was found for egg production data across three of the four sites. The length scales of the spatial covariance functions fitted to the egg production data ranged from 143 m to 574 m, indicating that high productivity regions can be extensive in size. Rank-correlation analyses indicated that mosquito presence tended to persist from the dry to wet season, but that egg production ranks at locations could reverse. The data suggest that, in Jeddah, the quality of the local environment for breeding can vary over time. The data support the feasibility of dry season releases but with release numbers needing to be flexible depending on local rates of invasion. [ABSTRACT FROM AUTHOR]

Introduction: Efficient epidemiological monitoring of virus diseases is crucial in evaluating general public health, the prevalence of specific diseases, the pattern of spread, and implementing preventative and control strategies into action. Methods: This study analyzed data obtained from the Field Epidemiology Program (FETP) which is part of the Ministry of Health (MOH) in Saudi Arabia, which contained reported cases of infectious diseases over four years, from January 2018 to December 2021, to investigate and highlight the significant trend and incidence rate for each viral infectious disease. Results: Of the reported viral infectious diseases, hepatitis B and C, dengue fever (DF), influenza, chickenpox, and measles were the highest reported viral cases over four years. For the aforementioned diseases, males were often more susceptible to viral infections than females. Except for DF, this viral infection was more common in Saudi citizens. Viral illnesses like hand, foot, and mouth disease were less prevalent, while neurological viral disorders such as acute flaccid paralysis were rarely detected. There was an overall reduction in viral cases recorded during 2020–2021, which may be attributed to the implementation of preventive measures during the Coronavirus Disease 2019 (COVID–19) pandemic or an underreporting of cases during the lockdown of that time. Conclusion: The prevalence of these common viral infections in the Saudi population suggests that understanding the mechanisms influencing changes in these viruses, methods of transmission, and the burden of these diseases is a priority for health policy. This understanding is necessary to develop effective intervention and preventive strategies. [ABSTRACT FROM AUTHOR]

Introduction: Bacterial infections have a significant impact on human health; they can cause severe morbidity and mortality, particularly in susceptible populations. Epidemiological surveillance is a critical tool for monitoring the population's health and facilitate the prevention and control of infectious disease outbreaks. Knowing the burden of bacterial communicable diseases is an initial core step toward public health goals. Methods: Saudi epidemiology surveillance data were utilized to depict the changing epidemiology of bacterial infectious diseases in Saudi Arabia from 2018 to 2021. The cumulative numbers of cases, demographics, and incidence rates were analyzed and visualized. Parametric tests were used to compare the difference in the mean values between categorical variables. Regression analysis was employed to estimate trends in disease rates over time. Statistical significance was set at p value ≤ 0.05. Results: The results revealed that brucellosis, tuberculosis, and salmonellosis were the most frequently reported bacterial infectious diseases in Saudi Arabia. Males were more significantly affected by brucellosis and tuberculosis infections than females. Salmonellosis infections were more significant among Saudi citizens, while pulmonary tuberculosis was more significant in non-Saudis. Interestingly, there was a decline in the incidence rates of numerous bacterial infectious diseases during the Coronavirus Disease 2019 (COVID-19) pandemic and COVID-19 restrictions. Some bacterial infectious diseases were rarely reported in Saudi Arabia, including syphilis and diphtheria. Conclusions: The future perspective of this research is to enhance disease surveillance reporting by including different variables, such as the source of infection, travel history, hospitalization, and mortality rates. The aim is to improve the sensitivity and specificity of surveillance data and focus on the mortality associated with bacterial pathogens to identify the most significant threats and set a public health priority. [ABSTRACT FROM AUTHOR]

Middle East respiratory syndrome coronavirus (MERS-CoV) is associated with significant morbidity and mortality. This study was performed to assess the proinflammatory cytokines profile among MERS-CoV patients. A total of 46 MERS-CoV–infected patients (27 symptomatic and 19 asymptomatic) were assessed and compared with 52 normal healthy controls for plasma levels of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-17, IL-7, IL-6, interferon (IFN)-α, and IL-15 using a customized luminex kit. Whereas asymptomatic MERS-CoV patients and controls were no different; the mean plasma levels among MERS-CoV symptomatic patients were significantly higher than the normal controls: IL-1β (16.89 ± 1.23 vs. 12.80 ± 0.59 pg/mL; p < 0.001), TNF-α (14.04 ± 0.93 vs. 10.35 ± 0.29 pg/mL; p < 0.0001), IL-17 (14.3 ± 0.89 vs. 11.47 ± 0.61 pg/mL; p < 0.001), IL-7 (21.56 ± 1.00 vs. 16.31 ± 0.30 pg/mL; p < 0.0001), IL-6 (156.5 ± 37.90 vs. 18.60 ± 1.59 pg/mL; p < 0.0001), and IFN-α (68.73 ± 13.06 vs. 23.57 ± 1.05 pg/mL; p < 0.0001). The mean plasma levels of IL-7 (24.81 ± 1.63 vs. 19.79 ± 0.94 pg/mL; p < 0.01), IL-6 (312.7 ± 94.67 vs. 101.2 ± 25.67 pg/mL; p < 0.01), and IFN-α (89.00 ± 18.97 vs. 51.05 ± 8.68 pg/mL; p < 0.05) were significantly elevated among MERS-CoV symptomatic patients with fatal outcome compared with MERS-CoV symptomatic patients who survived. Only IL-7 was found to have a higher risk ratio of mortality (4.76, 95% confidence interval: 1.5–14.94; p < 0.01). No differences were observed in IL-15 levels among the groups. Significantly elevated proinflammatory cytokines among symptomatic MERS-CoV–infected patients may contribute to manifestations of cytokine storm frequently observed among critically ill MERS-CoV patients and IL-7 may serve as a marker for disease activity. [ABSTRACT FROM AUTHOR]

Gene editing, especially with clustered regularly interspaced short palindromic repeats associated protein 9 (CRISPR-Cas9), has advanced gene function science. Gene editing's rapid advancement has increased its medical/clinical value. Due to its great specificity and efficiency, CRISPR/Cas9 can accurately and swiftly screen the whole genome. This simplifies disease-specific gene therapy. To study tumor origins, development, and metastasis, CRISPR/Cas9 can change genomes. In recent years, tumor treatment research has increasingly employed this method. CRISPR/Cas9 can treat cancer by removing genes or correcting mutations. Numerous preliminary tumor treatment studies have been conducted in relevant fields. CRISPR/Cas9 may treat gene-level tumors. CRISPR/Cas9-based personalized and targeted medicines may shape tumor treatment. This review examines CRISPR/Cas9 for tumor therapy research, which will be helpful in providing references for future studies on the pathogenesis of malignancy and its treatment. [ABSTRACT FROM AUTHOR]

Aedes aegypti mosquitoes carrying self-spreading, virus-blocking Wolbachia bacteria are being deployed to suppress dengue transmission. However, there are challenges in applying this technology in extreme environments. We introduced two Wolbachia strains into Ae. aegypti from Saudi Arabia for a release program in the hot coastal city of Jeddah. Wolbachia reduced infection and dissemination of dengue virus (DENV2) in Saudi Arabian mosquitoes and showed complete maternal transmission and cytoplasmic incompatibility. Wolbachia reduced egg hatch under a range of environmental conditions, with the Wolbachia strains showing differential thermal stability. Wolbachia effects were similar across mosquito genetic backgrounds but we found evidence of local adaptation, with Saudi Arabian mosquitoes having lower egg viability but higher adult desiccation tolerance than Australian mosquitoes. Genetic background effects will influence Wolbachia invasion dynamics, reinforcing the need to use local genotypes for mosquito release programs, particularly in extreme environments like Jeddah. Our comprehensive characterization of Wolbachia strains provides a foundation for Wolbachia-based disease interventions in harsh climates. Author summary: Wolbachia bacteria live inside the cells of many insects including mosquitoes. Wolbachia strains can block the transmission of dengue and other arboviruses transmitted by Aedes mosquitoes and are being introduced around the world for disease control. The success of this strategy relies on the ability of Wolbachia to spread locally by causing cytoplasmic incompatibility (embryo death when infected males mate with uninfected females), on Wolbachia having limited fitness costs in local mosquito hosts, and on Wolbachia persisting in the local mosquito background in the environmental conditions that mosquitoes encounter. Here we comprehensively assess the feasibility of using two Wolbachia strains in releases with Aedes aegypti mosquitoes in the challenging environment of Jeddah, Saudi Arabia. We show effective dengue virus blocking and incompatibility in both strains in the local mosquito genetic background but higher fitness costs for one strain which may offset its ability to maintain higher infection levels under the fluctuating temperatures expected in Jeddah. We find that the Jeddah Ae. aegypti are more resistant to desiccation, highlighting the importance of establishing infections in the local genetic background. These findings directly inform the employment of Wolbachia strategies in Jeddah and emphasize the value of testing the local context. [ABSTRACT FROM AUTHOR]

Herpes labialis, caused by herpes simplex virus type 1, is usually characterized by painful skin or mucosal lesions. Penciclovir (PV) tablets are found to be effective against herpes labialis but suffer from poor oral bioavailability. This study aimed to combine the benefits of PV and lavender oil (LO), which exhibits anesthetic activity, in the form of a self-nanoemulsifying drug delivery system (SNEDDS) for the treatment of herpes labialis. Toward this purpose, LO (oil), Labrasol:Labrafil M1944 CS in the ratio of 6:4 (surfactant mixture), and Lauroglycol-FCC (co-surfactant, selected based on the solubility of PV) were evaluated as the independent factors using a distance quadratic mixture design. The formulation was optimized for the minimum globule size and maximum stability index and was determined to contain 14% LO, 40.5% Labrasol:Labrafil 1944 (6:4), and 45.5% Lauroglycol-FCC. The optimized PV-LOSNEDDS was embedded in chitosan hydrogel and the resulting formulations coded by (O3) were prepared and evaluated. The rheological studies demonstrated a combined pseudoplastic and thixotropic behavior with the highest flux of PV permeation across sheep buccal mucosa. Compared to a marketed 1% PV cream, the O3 formulation exhibited a significantly higher and sustained PV release, nearly twice the PV permeability, and a relative bioavailability of 180%. Overall, results confirm that the O3 formulation can provide an efficient delivery system for PV to reach oral mucosa and subsequent prolonged PV release. Thus, the PV-LO-SNEDDS embedded oral gel is promising and can be further evaluated in clinical settings to establish its therapeutic use in herpes labialis. [ABSTRACT FROM AUTHOR]

Dihydromyricetin-mediated silver nanoparticles (DMY-AgNPs) were synthesized and their efficacy against fungal pathogens tested in vitro. The shape of DMY-AgNPs appeared to be spherical with size of ~34 nm. Fourier-transform infrared (FT-IR) analysis indicated that -OH and C=O groups were involved in nanoparticle formation. The XRD pattern of DMY-AgNPs showed strong peaks at 38°, 44°, and 64°, corresponding to reflection from (111), (200), and (220) planes. Five opportunistic fungal pathogens, namely Aspergillus fumigatus, Aspergillus niger, Paecilomyces formosus, Candida albicans, and Candida parapsilosis, were isolated from patients suffering from respiratory tract infections. Growth of each fungal strain was inhibited by DMY-AgNPs. The zone of inhibition of DMY-AgNPs against A. fumigatus, A. niger, P. formosus, C. albicans, and C. parapsilosis was 17.6, 19.2, 22.2, 15.8, and 18.5 mm. The minimal inhibitory concentration was found to be 0.83, 0.73, 0.67, 0.95, and 0.89 µg mL−1, respectively. This is the first report on DMY-AgNPs as an effective antifungal agent. DMY-AgNPs are a potential alternative to commercially available antifungal fungicidals. [ABSTRACT FROM AUTHOR]

Since the advent of mechanically interlocked molecules (MIMs), many approaches to templating their formation using various different noncovalent bonding interactions have been introduced and explored. In particular, employing radical-pairing interactions between BIPY.+ units, the radical cationic state of 4,4′-bipyridinium (BIPY2+) units, in syntheses is not only a convenient but also an attractive source of templation because of the unique properties residing in the resulting catenanes and rotaxanes. Herein, we report a copper-mediated procedure that enables the generation, in the MIM-precursors, of BIPY.+ radical cations, while the metal itself, which is oxidized to CuI, catalyzes the azide-alkyne cycloaddition reactions that result in the efficient syntheses of two catenanes and one rotaxane, assisted by radical-pairing interactions between the BIPY.+ radical cations. This procedure not only provides a fillip for making and investigating the properties of Coulombically challenged catenanes and rotaxanes, but it also opens up the possibility of synthesizing artificial molecular machines which operate away from equilibrium. [ABSTRACT FROM AUTHOR]

Since the advent of mechanically interlocked molecules (MIMs), many approaches to templating their formation using various different noncovalent bonding interactions have been introduced and explored. In particular, employing radical-pairing interactions between BIPY.+ units, the radical cationic state of 4,4′-bipyridinium (BIPY2+) units, in syntheses is not only a convenient but also an attractive source of templation because of the unique properties residing in the resulting catenanes and rotaxanes. Herein, we report a copper-mediated procedure that enables the generation, in the MIM-precursors, of BIPY.+ radical cations, while the metal itself, which is oxidized to CuI, catalyzes the azide-alkyne cycloaddition reactions that result in the efficient syntheses of two catenanes and one rotaxane, assisted by radical-pairing interactions between the BIPY.+ radical cations. This procedure not only provides a fillip for making and investigating the properties of Coulombically challenged catenanes and rotaxanes, but it also opens up the possibility of synthesizing artificial molecular machines which operate away from equilibrium. [ABSTRACT FROM AUTHOR]

Covalent and supramolecular polymerizations, both of which offer their own unique advantages, have emerged as popular strategies for making artificial materials. Herein, we describe a concurrent covalent and supramolecular polymerization strategy-namely, one which utilizes 1) a bis-azide-functionalized diazaperopyrenium dication that undergoes polymeriation covalently with a bis-alkyne-functionalized biphenyl derivative in one dimension as a result of a rapid and efficient β-cyclodextrin(CD)-accelerated, cucurbit[6]uril(CB)-templated azide-alkyne cycloaddition, while 2) the aromatic core of the dication is able to dimerize in a criss-cross fashion by dint of π-π interactions, enabling simultaneous supramolecular assembly, resulting in an extended polymer network in an orthogonal dimension. [ABSTRACT FROM AUTHOR]

Porous metal-organic frameworks (MOFs) have been studied in the context of a wide variety of applications, particularly in relation to molecular storage and separation sciences. Recently, we reported a green, renewable framework material composed ofγ-cyclodextrin (γ-CD) and alkali metal salts--namely, CD-MOF. This porous material has been shown to facilitate the separation of mixtures of alkylaromatic compounds, including the BTEX mixture (benzene, toluene, ethylbenzene, and the regioisomers of xylene), into their pure components, in both the liquid and gas phases, in an energy-efficient manner which could have implications for the petrochemical industry. Here, we report the ability of CD-MOF to separate a wide variety of mixtures, including ethylbenzene from styrene, haloaromatics, terpinenes, pinenes and other chiral compounds. CD-MOF retains saturated compounds to a greater extent than their unsaturated analogues. Also, the location of a double bond within a molecule influences its retention within the extended framework, as revealed in the case of the structural isomers of pinene and terpinine, where the isomers with exocyclic double bonds are more highly retained than those with endocyclic double bonds. The ability of CD-MOF to separate various mono- and disubstituted haloaromatic compounds appears to be controlled by both the size of the halogen substituents and the strength of the noncovalent bonding interactions between the analyte and the framework, an observation which has been confirmed by molecular simulations. Since CD-MOF is a homochiral framework, it is also able to resolve the enantiomers of chiral analytes, including those of limonene and 1-phenylethanol. These findings could lead to cheaper and easier-to-prepare stationary phases for HPLC separations when compared with other chiral stationary phases, such as CD-bonded silica particles. [ABSTRACT FROM AUTHOR]

The synthesis and recognition phenomena of a tetracationic molecular receptor that possesses a nanometer-sized molecular cavity are described. The host-guest properties of the molecular receptor can be tuned and modulated allosterically, where the association of a heterotropic effector at the periphery of the molecule serves to modulate its affinity for the globular, electron-rich guest that resides within its molecular cavity. This stimuli-responsive host-guest behavior was observed in both the solution phase and the crystalline solid state, and can be reversed with high fidelity by sequestration of the effector molecule. [ABSTRACT FROM AUTHOR]

Metal--organic frameworks (MOFs) are known to facilitate energy-efficient separations of important industrial chemical feedstocks. Here, we report how a class of green MOFs--namely CD-MOFs--exhibits high shape selectivity toward aromatic hydrocarbons. CD-MOFs, which consist of an extended porous network of γ-cyclodextrins (γ-CDs) and alkali metal cations, can separate a wide range of benzenoid compounds as a result of their relative orientation and packing within the transverse channels formed from linking (γ-CD)6 body-centered cuboids in three dimensions. Adsorption isotherms and liquid-phase chromatographic measurements indicate a retention order of ortho- > meta- > para-xylene. The persistence of this regioselectivity is also observed during the liquid-phase chromatography of the ethyltoluene and cymene regioisomers. In addition, molecular shape-sorting within CD-MOFs facilitates the separation of the industrially relevant BTEX (benzene, toluene, ethylbenzene, and xylene isomers) mixture. The high resolution and large separation factors exhibited by CD-MOFs for benzene and these alkylaromatics provide an efficient, reliable, and green alternative to current isolation protocols. Furthermore, the isolation of the regioisomers of (i) ethyltoluene and (ii) cymene, together with the purification of (iii) cumene from its major impurities (benzene, n-propylbenzene, and diisopropylbenzene) highlight the specificity of the shape selectivity exhibited by CD-MOFs. Grand canonical Monte Carlo simulations and single component static vapor adsorption isotherms and kinetics reveal the origin of the shape selectivity and provide insight into the capability of CD-MOFs to serve as versatile separation platforms derived from renewable sources. [ABSTRACT FROM AUTHOR]

A versatile surface-functionalization strategy applicable to mesoporous silica nanoparticles, which could potentially serve as drug delivery vehicles, is described that makes use of alkoxyamine tethers on the surface of the nanoparticles. A wide variety of carbonyl compounds can be attached readily to these tethers under the mild conditions of oxime ether formation, simply by incubating the chemically modified mesoporous silica nanoparticles with aldehydes or ketones in water. [ABSTRACT FROM AUTHOR]

We report the synthesis of a series of homologous oligoviologens in which different numbers of 4,4'-bipyridinium (BIPY2+) subunits are linked by p-xylylene bridges, as a prelude to investigating how their radical cationic forms self-assemble both in solution and in the solid state. The strong radical--radical interactions between the radical cationic forms of the BIPY2+ units--namely, BIPY*+--in these oligoviologens induce intra- or intermolecular folding of these homologues. UV/Vis/NIR spectroscopic studies and DFT quantum mechanics indicate that the folding of the shorter oligoviologens is dominated by intermolecular radical--radical interactions. In addition to intermolecular interactions, strong intramolecular radical--radical interactions, which give rise to an NIR absorption band at 900 nm, tend to play a crucial role in governing the folding of the longer oligoviologens. The solid-state superstructure of the oligoviologen with three BIPY2+ units reveals that two intertwining chains fold together to form a dimer, stabilized by intermolecular radical--radical interactions. These dimers continue to stack in an infinite column through intermolecular radical--radical interactions between them. This research features an artificial biomimetic system which sustains delicate secondary and tertiary structures, reminiscent of those present in nucleic acids and proteins. [ABSTRACT FROM AUTHOR]

Organic charge transfer cocrystals are inexpensive, modular, and solution-processable materials that are able, in some instances, to exhibit properties such as optical nonlinearity, (semi) conductivity, ferroelectricity, and magnetism. Although the properties of these cocrystals have been investigated for decades, the principal challenge that researchers face currently is to devise an efficient approach which allows for the growth of high-quality crystalline materials, in anticipation of a host of different technological applications. The research reported here introduces an innovative design, termed LASO--lock-arm supramolecular ordering--in the form of a modular approach for the development of responsive organic cocrystals. The strategy relies on the use of aromatic electronic donor and acceptor building blocks, carrying complementary rigid and flexible arms, capable of forming hydrogen bonds to amplify the cocrystallization processes. The cooperativity of charge transfer and hydrogen-bonding interactions between the building blocks leads to binary cocrystals that have alternating donors and acceptors extending in one and two dimensions sustained by an intricate network of hydrogen bonds. A variety of air-stable, mechanically robust, centimeterlong, organic charge transfer cocrystals have been grown by liquid--liquid diffusion under ambient conditions inside 72 h. These cocrystals are of considerable interest because of their remarkable size and stability and the promise they hold when it comes to fabricating the next generation of innovative electronic and photonic devices. [ABSTRACT FROM AUTHOR]

Precise control of molecular assembly is a challenging goal facing supramolecular chemists. Herein, we report the highly specific assembly of a range of supramolecular nanotubes from the enantiomeric triangular naphthalenediimide-based macrocycles (RKRRRR)- and (SSSSSS)-NDI-Δ and a class of similar solvents, namely, the 1,2-dihalo-ethanes and -ethenes (DXEs). Three kinds of supramolecular nanotubes are formed from the columnar stacking of NDI-Δ units with a 60° mutual rotation angle as a result of cooperative [C--H…0] interactions, directing interactions of the [X…X]-bonded DXE chains inside the nanotubes and lateral [X…π] or [π…π] interactions. They include (i) semiflexible infinite nanotubes formed in the gel state from NDI-Δ and (E)-1,2-dichloroethene, (ii) rigid infinite nonhelical nanotubes produced in the solid state from NDI-π and BrCH2CH2Br, ClCH2CH2 Br, and ClCH2CH2 I, and (iii) a pair of rigid tetrameric, enantiomeric single-handed (P)- and (M)-helical nanotubes formed in the solid state from the corresponding (RRRRRR)- and (SSSSSS)-NDI-π with ClCH2CH2Cl. In case (i), only the electron-rich C = C double bond of (E)-1,2-dichloroethene facilitates the gelation of NDI-π. In cases (ii) and (iii), the lengths of anti-DXRs determine the translation of the chirality of NDI-π into the helicity of nanotubes. Only ClCH2CH2Cl induces single-handed helicity into the nanotubes. The subtle interplay of noncovalent bonding interactions, resulting from the tiny structural variations involving the DXE guests, is responsible for the diverse and highly specific assembly of NDI-π. This research highlights the critical role that guests play in constructing assembled superstructures of hosts and offers a novel approach to creating supramolecular nanotubes. [ABSTRACT FROM AUTHOR]

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe respiratory illness in humans; the second-largest and most deadly outbreak to date occurred in Saudi Arabia. The dromedary camel is considered a possible host of the virus and also to act as a reservoir, transmitting the virus to humans. Here, we studied evolutionary relationships for 31 complete genomes of betacoronaviruses, including eight newly sequenced MERS-CoV genomes isolated from dromedary camels in Saudi Arabia. Through bioinformatics tools, we also used available sequences and 3D structure of MERS-CoV spike glycoprotein to predict MERS-CoV epitopes and assess antibody binding affinity. Phylogenetic analysis showed the eight new sequences have close relationships with existing strains detected in camels and humans in Arabian Gulf countries. The 2019-nCov strain appears to have higher homology to both bat coronavirus and SARS-CoV than to MERS-CoV strains. The spike protein tree exhibited clustering of MERS-CoV sequences similar to the complete genome tree, except for one sequence from Qatar (KF961222). B cell epitope analysis determined that the MERS-CoV spike protein has 24 total discontinuous regions from which just six epitopes were selected with score values of >80%. Our results suggest that the virus circulates by way of camels crossing the borders of Arabian Gulf countries. This study contributes to finding more effective vaccines in order to provide long-term protection against MERS-CoV and identifying neutralizing antibodies. [ABSTRACT FROM AUTHOR]