Engaging Same-Day Peer Ambassadors to Increase Coronavirus Disease 2019 Vaccination Among People Experiencing Unsheltered Homelessness in Los Angeles County: A Hybrid Feasibility-Evaluation Study.

BACKGROUND: This study aimed to evaluate the feasibility and acceptability of engaging unhoused peer ambassadors (PAs) in coronavirus disease 2019 (COVID-19) vaccination efforts to reach people experiencing unsheltered homelessness in Los Angeles County. METHODS: From August to December 2021, vaccinated PAs aged ≥18 years who could provide informed consent were recruited during vaccination events for same-day participation. Events were held at encampments, service providers (eg, housing agencies, food lines, and mobile showers), and roving locations around Los Angeles. PAs were asked to join outreach alongside community health workers and shared their experience getting vaccinated, receiving a $25 gift card for each hour they participated. Postevent surveys evaluated how many PAs enrolled and how long they participated. In October 2021, we added a preliminary effectiveness evaluation of how many additional vaccinations were attributable to PAs. Staff who enrolled the PAs estimated the number of additional people vaccinated because of talking with the PA. RESULTS: A total of 117 PAs were enrolled at 103 events, participating for an average of 2 hours. At events with the effectiveness evaluation, 197 additional people were vaccinated over 167 PA hours ($21.19 gift card cost per additional person vaccinated), accounting for >25% of all vaccines given at these events. DISCUSSION: Recruiting same-day unhoused PAs is a feasible, acceptable, and preliminarily effective technique to increase COVID-19 vaccination in unsheltered settings. The findings can inform delivery of other health services for people experiencing homelessness.

Community Health Worker Perspectives on Engaging Unhoused Peer Ambassadors for COVID-19 Vaccine Outreach in Homeless Encampments and Shelters.

BACKGROUND: COVID-19 vaccination is a priority for people experiencing homelessness. However, there are barriers to vaccine access driven in part by mistrust towards clinicians and healthcare. Community health workers (CHWs) and Peer Ambassadors (PAs) may be able to overcome mistrust in COVID-19 vaccine outreach. An unhoused PA program for COVID-19 vaccine outreach by CHWs was implemented in Los Angeles using a participatory academic-community partnership. OBJECTIVE: The purpose of this study was to evaluate CHW perspectives on an unhoused PA COVID-19 vaccine outreach program in Los Angeles. DESIGN: This study used a participatory community conference and qualitative focus groups to understand CHW perspectives on the PA program. The one-day conference was held in November 2021. PARTICIPANTS: Of the 42 conference participants, 19 CHWs participated in focus groups for two-way knowledge exchange between CHWs and researchers. APPROACH: Four focus groups were held during the conference, with 4-6 CHWs per group. Each group had a facilitator and two notetakers. Focus group notes were then analyzed using content analysis to derive categories of findings. CHWs reviewed the qualitative analysis to ensure that findings represented their experiences with the PA program. KEY RESULTS: The five categories of findings from focus groups were as follows: (1) PAs were effective liaisons to their peers to promote COVID-19 vaccines; (2) CHWs recognized the importance of establishing genuine trust and equitable working relationships within CHW/PA teams; (3) there were tradeoffs of integrating unhoused PAs into the existing CHW workflow; (4) CHWs had initial misgivings about the research process; and (5) there were lingering questions about the ethics of "exploiting" the invaluable trust unhoused PAs have with unhoused communities. CONCLUSIONS: CHWs were in a unique position to empower unhoused PAs to take a leadership role in reaching their peers with COVID-19 vaccines and advocate for long-term employment and housing needs.

Bio-Applications of Calix[n]arene Capped Silver Nanoparticles.

During the 10 last years, there has been a growing interest in calix[n]arene capped silver nanoparticles for their uses in biosensing and much more recently for their intrinsic therapeutic properties. Cost effective, portable and ultra-sensitive analytical tools are one of the major expectations of silver nanoparticles capped with calix[n]arenes. Their uses for detecting a wide range of hazardous molecules and biological compounds by different physical approaches (optical or electrical) are reviewed in depth here. A second part deals with their biological activities. These hybrid nanoparticles have been shown to possess antibacterial properties, and to reach antiviral and anti-cancer targets.

Promises of anionic calix[n]arenes in life science: State of the art in 2023.

Because they hold together molecules by means of non-covalent interactions - relatively weak and thus, potentially reversible - the anionic calixarenes have become an interesting tool for efficiently binding a large range of ligands - from gases to large organic molecules. Being highly water soluble and conveniently biocompatible, they showed growing interest for many interdisciplinary fields, particularly in biology and medicine. Thanks to their intrinsic conical shape, they provide suitable platforms, from vesicles to bilayers. This is a valuable characteristic, as so they mimic the biologically functional architectures. The anionic calixarenes propose efficient alternatives for overcoming the limitations linked to drug delivery and bioavailability, as well as drug resistance along with limiting the undesirable side effects. Moreover, the dynamic non-covalent binding with the drugs enables predictable and on demand drug release, controlled by the stimuli present in the targeted environment. This particular feature instigated the use of these versatile, stimuli-responsive compounds for sensing biomarkers of diverse pathologies. The present review describes the recent achievements of the anionic calixarenes in the field of life science, from drug carriers to biomedical engineering, with a particular outlook on their applications for the diagnosis and treatment of different pathologies.

Solid lipid nanoparticle-based calix[n]arenes and calix-resorcinarenes as building blocks: synthesis, formulation and characterization.

Solid lipid nanoparticles (SLNs) have attracted increasing attention during recent years. This paper presents an overview about the use of calix[n]arenes and calix-resorcinarenes in the formulation of SLNs. Because of their specific inclusion capability both in the intraparticle spaces and in the host cavities as well as their capacity for functionalization, these colloidal nanostructures represent excellent tools for the encapsulation of different active pharmaceutical ingredients (APIs) in the area of drug targeting, cosmetic additives, contrast agents, etc. Various synthetic routes to the supramolecular structures will be given. These various routes lead to the formulation of the corresponding SLNs. Characterization, properties, toxicological considerations as well as numerous corresponding experimental studies and analytical methods will be also exposed and discussed.

Anionic calixarene-capped silver nanoparticles show species-dependent binding to serum albumins.

The anionic calixarenes para-sulphonatocalix[4]arene and 1,3-di-O-phosphonatocalix[ 4]arene, have been used to cap silver nanoparticles. The binding of these functional particles with regard to various serum albumins (bovine serum albumin, human serum albumin, porcine serum albumin and sheep serum albumin) has been studied by variable temperature fluorescence spectroscopy. The quenching of the fluorescence of the proteins was shown to vary as a function of the anionic calixarene capping molecule and also as a function of the origin of the serum albumin. It is thus possible to discriminate between the different species.

One-pot functionalization of graphene with porphyrin through cycloaddition reactions.

Two types of graphene-based hybrid materials, graphene-TPP (TPP=tetraphenylporphyrin) and graphene-PdTPP (PdTPP=palladium tetraphenylporphyrin), were prepared directly from pristine graphene through one-pot cycloaddition reactions. The hybrid materials were characterized by thermogravimetric analysis (TGA), by TEM, by UV/Vis, FTIR, Raman, and luminescence spectroscopy, and by fluorescence/phosphorescence lifetime measurements. The presence of the covalent linkages between graphene and porphyrin was confirmed by FTIR and Raman spectroscopy and further supported by control experiments. The presence of TPP (or PdTPP) in the hybrid material was demonstrated by UV/Vis spectroscopy, with TGA results indicating that the graphene-TPP and graphene-PdTPP hybrid materials contained approximately 18 % TPP and 20 % PdTPP. The quenching of fluorescence (or phosphorescence) and reduced lifetimes suggest excited state energy/electron transfer between graphene and the covalently attached TPP (or PdTPP) molecules.

The structure of water in p-sulfonatocalix[4]arene.

Tetrasodium p-sulfonatocalix[4]arene exists as a hydrate with approximately 14 water molecules and has three polymorphic modifications, all of which contain a water molecule in the molecular cavity that is engaged in OH···π interactions. Single-crystal neutron structures are reported for two of these three forms and reveal a "compressed" water molecule with short OH bonds. Partial atomic charges and hardness analysis (PACHA) calculations based on the neutron coordinates give an OH···π interaction energy of 6.9-7.5 kJ mol(-1). The PACHA analysis also reveals the dominance of the charge-assisted hydrogen bonds from the Na(+)-coordinated water molecules. The instability of the crystal towards dehydration can be traced to an uncoordinated lattice water site. The remarkable calixarene-Na(+)-hydrate motif is conserved almost unchanged across all three polymorphs. A single-crystal neutron structure is also reported for pentasodium p-sulfonatocalix[4]arene·12H(2)O, which exhibits an intracavity water molecule that is engaged in both OH···π and OH···O hydrogen bonding. The shorter covalent bond to the hydrogen atom that forms the interaction with the aromatic ring is again apparent.

Evidence for cobalt-cobalt bond homolysis and wavelength-dependent CO loss in (µ2-alkyne)Co2(CO)6 complexes.

Time-resolved infrared spectroscopy was used to probe the photochemistry of three (µ(2)-alkyne)Co(2)(CO)(6) complexes. The data indicate the formation of a triplet diradical species, with lifetimes in the range 38-71 ps. Theoretical calculations support these experimental findings. No evidence for the CO loss species, (µ(2)-alkyne)Co(2)(CO)(5), was observed, and this is rationalized by the low quantum yield for this process at the excitation wavelengths used.

Solid lipid nanoparticles (SLNs) derived from para-acyl-calix[9]-arene: preparation and stability.

A study of the parameters relating to the preparation of para-acyl-calix[9]arene-based solid lipid nanoparticles (SLNs) has been undertaken. Dynamic light scattering and electron microscopy have shown that the particle size varies between 85 and 215 nm depending on the acyl chain length. Parameters, including the organic solvent, amphiphile concentration and the presence of a co-surfactant affect the size of the SLNs obtained significantly. In contrast, stirring speed and solution viscosity have no effect. The ionic strength of the suspension has been shown to affect SLN stability in a salt-dependent manner. Ultrasonic and ultraviolet and 80°C treatment of the SLN suspensions have no effect on the SLN stability. The SLNs are unstable with respect to freezing–defreezing cycles, but can be reconstituted using mono- or disaccharides as cryoprotectants. Importantly, the temporal stability of these suspensions in water has been shown to be superior to 6 months. With regard to protein interactions, no SLN aggregation was observed in the presence of human serum albumin, with formation of a monolayer of albumin on the surface of the SLNs. Encapsulation was shown using acridine as a fluorescent probe.

Streptidinium sulfate monohydrate.

In streptidinium sulfate monohydrate {systematic name: 1,1'-[(1S,3R,4S,6R)-2,4,5,6-tetrahydroxycyclohexane-1,3-diyl]diguanidinium sulfate monohydrate}, C(8)H(20)N(6)O(4)(2+).SO(4)(2-).H(2)O, at 100 (2) K, the components are arranged in double helices based on hydrogen bonds. One helix contains streptidinium cations and the other contains disordered sulfate anions and solvent water molecules. The helices are linked into a three-dimensional hydrogen-bonded network by O-H...O and N-H...O hydrogen bonds.

Direct measurement of the mechanical properties of a chromatin analog and the epigenetic effects of para-sulphonato-calix[4]arene.

By means of Silicon Nano Tweezers (SNTs) the effects on the mechanical properties of λ-phage DNA during interaction with calf thymus nucleosome to form an artificial chromatin analog were measured. At a concentration of 100 nM, a nucleosome solution induced a strong stiffening effect on DNA (1.1 N m-1). This can be compared to the effects of the histone proteins, H1, H2A, H3 where no changes in the mechanical properties of DNA were observed and the complex of the H3/H4 proteins where a smaller increase in the stiffness is observed (0.2 N m-1). Para-sulphonato-calix[4]arene, SC4, known for epigenetic activity by interacting specifically with the lysine groups of histone proteins, was studied for its effect on an artificial chromatin. Using a microfluidic SNT device, SC4 was titrated against the artificial chromatin, at a concentration of 1 mM in SC4 a considerable increase in stiffness, 15 N m-1, was observed. Simultaneously optical microscopy showed a physical change in the DNA structure between the tips of the SNT device. Electronic and Atomic Force microscopy confirmed this structural re-arrangement. Negative control experiments confirmed that these mechanical and physical effects were induced neither by the acidity of SC4 nor through nonspecific interactions of SC4 on DNA.

Size and Flexibility Define the Inhibition of the H3N2 Influenza Endonuclease Enzyme by Calix[n]arenes.

Inhibition of H3N2 influenza PA endonuclease activity by a panel of anionic calix[n]arenes and ß-cyclodextrin sulfate has been studied. The joint experimental and theoretical results reveal that the larger, more flexible and highly water-soluble sulfonato-calix[n]arenes have high inhibitory activity, with para-sulfonato-calix[8]arene, SC8, having an IC50 value of 6.4 µM. Molecular docking calculations show the SC8 can interact at both the polyanion binding site and also the catalytic site of H3N2 influenza PA endonuclease.

para-Sulphonato-calix[n]arene capped silver nanoparticles challenge the catalytic efficiency and the stability of a novel human gut serine protease inhibitor.

The Eubacterium saburreum serine protease inhibitor from the human gut microbiota inhibits the eukaryotic pancreatic elastase associated with acute pancreatitis. Interestingly, the inhibition efficiency and stability are markedly increased by the para-sulphonato-calix[8]arene capped silver nanoparticles. Moreover, this enzyme is distinguishable by its high inhibitory effect at broad pH range between 2-10 and temperatures from 10 to 40 °C, in the presence of para-sulphonato-calix[8]arene capped silver nanoparticles the enzyme remains active even at 70 °C.

Fused Deposition Modeling 3D Printing: Test Platforms for Evaluating Post-Fabrication Chemical Modifications and In-Vitro Biological Properties.

3D printing is attracting considerable interest for its capacity to produce prototypes and small production runs rapidly. Fused deposit modeling (FDM) was used to produce polyvalent test plates for investigation of the physical, chemical, and in-vitro biological properties of printed materials. The polyvalent test plates (PVTPs) are poly-lactic acid cylinders, 14 mm in diameter and 3 mm in height. The polymer ester backbone was surface modified by a series of ramified and linear oligoamines to increase its hydrophilicity and introduce a positive charge. The chemical modification was verified by FT-IR spectroscopy, showing the introduction of amide and amine functions, and contact angle measurements confirmed increased hydrophilicity. Morphology studies (SEM, optical microscopy) indicated that the modification of PVTP possessed a planar morphology with small pits. Positron annihilation lifetime spectroscopy demonstrated that the polymeric free volume decreased on modification. An MTT-based prolonged cytotoxicity test using Caco-2 cells showed that the PVTPs are non-toxic at the cellular level. The presence of surface oligoamines on the PVTPs reduced biofilm formation by Candida albicans SC5314 significantly. The results demonstrate that 3D printed objects may be modified at their surface by a simple amidation reaction, resulting in a reduced propensity for biofilm colonization and cellular toxicity.

Prion early kinetics revisited using a streptomycin-based PrP(res) extraction method.

The use of streptomycin in the PrP(sc) detection procedures represents a new and attractive way to detect more PrP(sc), the best marker for the transmissible spongiform encephalopathies (TSEs). Actually, the streptomycin PrP(sc) aggregating property reported recently was established as beneficial in PrP(sc) detection using immunohistochemistry in diagnostic as well as in experimental conditions. The present study reports in details how to use advantageously this original streptomycin property in PrP(res) biochemical extraction and detection. Using TSE diagnostic brain material, specificity and increased sensitivity using streptomycin-treated samples were substantiated. Then an early sequential brain and spleen sampling (from 7 to 49 days post-inoculation) from C57Bl/6 mice inoculated intra-cerebrally or intra-peritoneally with C506M3 scrapie strain was analysed using streptomycin versus ultracentrifugation PrP(res) extraction. Whatever the inoculation route, streptomycin allowed earlier PrP(res) detection in spleen (7 d.p.i.), then in brain suggesting a stronger affinity of the infectious agent for the lymphoid compartment.

para-Acylcalix[n]arenes: from molecular to macroscopic assemblies.

The para-acylcalix[n]arenes possess a very rich capacity to self-assemble into a wide variety of structures and sizes ranging from molecular assemblies through dimeric capsules, molecular sheets to nanoparticles. All these assemblies are capable of taking guest molecules and in the process of this inclusion discrete nanoscopic reaction vessels may be formed for photochemistry. Interestingly this uptake of quite large organic molecules occurs in the bulk in non-porous crystals without loss of crystallinity. At the air-water interface either as Langmuir monolayers or as colloidal suspensions the para-acylcalix[n]arenes show interaction with ionic species. The extension from para-acylcalix[4]arenes to para-acylcalix[8]arenes is in its infancy but already there is much promise for novel assemblies to be found.

Crystalline inclusion complex of a calixarene with a nitroxide.

The first capsular crystalline inclusion complex of para-hexanoyl calix[4]arene with stable nitroxyl radical DEPN has been isolated and showed a low mobility of the radical in the capsule.

Synthesis, electrochemistry, and photophysical properties of a series of luminescent pyrene-thiophene dyads and the corresponding Co2(CO)6 complexes.

A series of pyrene based dyad systems together with their dicobalt hexacarbonyl complexes (1b-6b) were synthesized. The pyrene-thiophene dyads are luminescent in room temperature solution with luminescence lifetimes on the nanosecond time scale. At room temperature the dyad emission is quenched by coordination to a Co(2)(CO)(6) moiety via an acetylene bridge. However, at 77 K this emission is not fully quenched following complexation. Electrochemical studies suggest that an intraligand state is responsible for the emission. Photochemical studies in the presence of PPh(3) indicate that CO loss occurs following broadband irradiation with lambda(exc) > 400 nm, resulting in the formation of both -pentacarbonyl and -tetracarbonyl photoproducts.

Elucidating the mechanism of the considerable mechanical stiffening of DNA induced by the couple Zn2+/Calix[4]arene-1,3-O-diphosphorous acid.

The couple Calix[4]arene-1,3-O-diphosphorous acid (C4diP) and zinc ions (Zn2+) acts as a synergistic DNA binder. Silicon NanoTweezer (SNT) measurements show an increase in the mechanical stiffness of DNA bundles by a factor of >150, at Zn2+ to C4diP ratios above 8, as compared to Zinc alone whereas C4diP alone decreases the stiffness of DNA. Electroanalytical measurements using 3D printed devices demonstrate a progression of events in the assembly of C4diP on DNA promoted by zinc ions. A mechanism at the molecular level can be deduced in which C4diP initially coordinates to DNA by phosphate-phosphate hydrogen bonds or in the presence of Zn2+ by Zn2+ bridging coordination of the phosphate groups. Then, at high ratios of Zn2+ to C4diP, interdigitated dimerization of C4diP is followed by cross coordination of DNA strands through Zn2+/C4diP inter-strand interaction. The sum of these interactions leads to strong stiffening of the DNA bundles and increased inter-strand binding.