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Background Our understanding of the global scale of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection remains incomplete: Routine surveillance data underestimate infection and cannot infer on population immunity; there is a predominance of asymptomatic infections, and uneven access to diagnostics. We meta-analyzed SARS-CoV-2 seroprevalence studies, standardized to those described in the World Health Organization’s Unity protocol (WHO Unity) for general population seroepidemiological studies, to estimate the extent of population infection and seropositivity to the virus 2 years into the pandemic. Methods and findings We conducted a systematic review and meta-analysis, searching MEDLINE, Embase, Web of Science, preprints, and grey literature for SARS-CoV-2 seroprevalence published between January 1, 2020 and May 20, 2022. The review protocol is registered with PROSPERO (CRD42020183634). We included general population cross-sectional and cohort studies meeting an assay quality threshold (90% sensitivity, 97% specificity; exceptions for humanitarian settings). We excluded studies with an unclear or closed population sample frame. Eligible studies—those aligned with the WHO Unity protocol—were extracted and critically appraised in duplicate, with risk of bias evaluated using a modified Joanna Briggs Institute checklist. We meta-analyzed seroprevalence by country and month, pooling to estimate regional and global seroprevalence over time; compared seroprevalence from infection to confirmed cases to estimate underascertainment; meta-analyzed differences in seroprevalence between demographic subgroups such as age and sex; and identified national factors associated with seroprevalence using meta-regression. We identified 513 full texts reporting 965 distinct seroprevalence studies (41% low- and middle-income countries [LMICs]) sampling 5,346,069 participants between January 2020 and April 2022, including 459 low/moderate risk of bias studies with national/subnational scope in further analysis. By September 2021, global SARS-CoV-2 seroprevalence from infection or vaccination was 59.2%, 95% CI [56.1% to 62.2%]. Overall seroprevalence rose steeply in 2021 due to infection in some regions (e.g., 26.6% [24.6 to 28.8] to 86.7% [84.6% to 88.5%] in Africa in December 2021) and vaccination and infection in others (e.g., 9.6% [8.3% to 11.0%] in June 2020 to 95.9% [92.6% to 97.8%] in December 2021, in European high-income countries [HICs]). After the emergence of Omicron in March 2022, infection-induced seroprevalence rose to 47.9% [41.0% to 54.9%] in Europe HIC and 33.7% [31.6% to 36.0%] in Americas HIC. In 2021 Quarter Three (July to September), median seroprevalence to cumulative incidence ratios ranged from around 2:1 in the Americas and Europe HICs to over 100:1 in Africa (LMICs). Children 0 to 9 years and adults 60+ were at lower risk of seropositivity than adults 20 to 29 (p < 0.001 and p = 0.005, respectively). In a multivariable model using prevaccination data, stringent public health and social measures were associated with lower seroprevalence (p = 0.02). The main limitations of our methodology include that some estimates were driven by certain countries or populations being overrepresented. Conclusions In this study, we observed that global seroprevalence has risen considerably over time and with regional variation; however, over one-third of the global population are seronegative to the SARS-CoV-2 virus. Our estimates of infections based on seroprevalence far exceed reported Coronavirus Disease 2019 (COVID-19) cases. Quality and standardized seroprevalence studies are essential to inform COVID-19 response, particularly in resource-limited regions.

The inclusion of local residents in public land management decisions is critical to the long-term success and equity - specifically the procedural equity of transparent, accountable, and participatory decision-making structures - of protected areas worldwide.A first step to integrating the diverse views of residents into decision-making is to understandthe potential range of perspectives on various environmental topics. Inclusive conservation,which aims to represent the multiple viewpoints across a range of stakeholders, is an especiallyapplicable framework for guiding decisions being made about for protected areas in the U.S.state of Alaska. Residents of the state feel a strong sense of community and connection to theland, but many feel that their local views are not integrated across regional and national decision-makingstrategies. The purpose of our research is therefore to provide insight into the values,beliefs, and behaviors of Alaska residents to better support protected area management focusedon equalizing opportunities for engagement of diverse stakeholders in a rapidly changing world.Our study is designed to generate information that will help researchers, decision-makers, and/orother stakeholders betterunderstand and more effectively engage with Alaska residents aroundtopics of protected area management. To do so, we collected data through an online surveyadministered to residents living across the state. We examined a number of environmental topics to better understand the perspectives of residents on public land management throughout Alaska.

The reaction between the previously reported site-differentiated cluster solvate [Re(6)(mu(3)-Se)(8)(PEt(3))(5)(MeCN)](SbF(6))(2) (1) with pyridyl-based ditopic ligands 4,4'-trimethylenedipyridine (2), 1,2-bis(4-pyridyl)ethane (3), and (E)-1,2-bis(4-pyridyl)ethene (4) afforded cluster complexes of the general formula [Re(6)(mu(3)-Se)(8)(PEt(3))(5)(L)](SbF(6))(2) (5-7), where L represents one of the pyridyl-based ligands. Reacting these cluster complex-based ligands with the fully solvated cluster complex [Re(6)(mu(3)-Se)(8)(MeCN)(6)](SbF(6))(2) (8) produced dendritic arrays of the general formula {Re(6)(mu(3)-Se)(8)[Re(6)(mu(3)-Se)(8)(PEt(3))(5)(L)](6)}(SbF(6))(14) (9-11), each featuring six circumjacent [Re(6)(mu(3)-Se)(8)(PEt(3))(5)](2+) units bridged to a [Re(6)(mu(3)-Se)(8)](2+) core cluster by the pyridyl-based ligands. Electrochemical studies using a thin-layer electrochemical cell revealed cluster-based redox events in these cluster arrays. For 9 (L = 2), one reversible oxidation event corresponding to the removal of 7 electrons was observed, indicating noninteraction or extremely weak interactions between the clusters. For 10 (L = 3), two poorly resolved oxidation waves were found. For 11 (L = 4), two reversible oxidation events, corresponding respectively to the removal of 1 and 6 electrons, were observed with the 1-electron oxidation event occurring at a potential 150 mV more positive than the 6-electron oxidation. These electrochemical studies suggest intercluster coupling in 11 via through-bond electronic delocalization, which is consistent with electronic spectroscopic studies of this same molecule.

A tetracluster array {[Re 6 ( μ 3 -Se) 8 (PEt 3 ) 5 ] 4 [5,10,15,20-tetra(4-pyridyl)-21 H ,23 H -porphine]}(SbF 6 ) 8 ( R 4 ) featuring a central porphyrin core and four circumjacent [Re 6 ( μ 3 -Se) 8 ] 2+ units was synthesized by reacting the previously reported cluster solvate [Re 6 ( μ 3 -Se) 8 (PEt 3 ) 5 (MeCN)](SbF 6 ) 2 ( R ) with 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine. Metallation of R 4 with metal (Co 2+ , Ni 2+ , Cu 2+ , Zn 2+ ) salts afforded the corresponding cluster-studded metalloporphyrins ( R 4 – Co , R 4 – Ni , R 4 – Cu , and R 4 – Zn ). All compounds were characterized by 1 H and 31 P NMR spectroscopy and elemental analysis (CHN). Electrochemical studies revealed one chemically reversible oxidation event attributable to the simultaneous removal of four electrons, one from each of the four cluster units. The uncoupled redox event suggests minimal electrical communication between the cluster sites. The cluster arrays were also studied by UV–vis spectroscopy. The electronic spectra of R 4 – Co , R 4 – Ni , and R 4 – Cu each showed the absorptions of the metalloporphyrins and the cluster complex. For R 4 – Zn , solvatochromism was observed. Its electronic absorptions in a variety of solvents of different dielectric constants were studied. To cite this article: B.K. Roland et al., C. R. Chimie 8 (2005) .

We report here an investigation of absorbance anisotropy in highly ordered, single bilayer (ca. 5.6 nm) Langmuir-Blodgett (LB) thin films of discotic liquid-crystalline phthalocyanines, using a recently introduced broad-band attenuated total reflectance (ATR) spectroscopic technique, capable of measuring dichroism in such films in the UV--visible optical region down to absorbances of ca. 0.003 absorbance units. On the basis of the ATR measurements of LB-deposited films, a thorough treatment was established to determine the ensemble average of the Cartesian components and the associated optical anisotropy of transition dipoles in the molecular film. In an effort to recover order parameters of molecular orientation, those results were interpreted with a circular dipole model, which is the expected model for the isolated molecule based on symmetry properties. We measured a strong dipole component normal to the film plane that cannot be explained in terms of a truly circular model, indicating that the molecular transition dipoles were perturbed upon aggregation. The utility of the experimental approach was further demonstrated by (a) investigating the effect of substrate modifiers (methyl- and phenyl-terminated silanes) on the ordering within the phthalocyanine film and (b) the effect of water immersion and re-annealing of the thin film on molecular ordering and optical anisotropy.

The cluster complex, “Re6(μ3-Se)8(PEt3)5(4-vinylpyridine)”(SbF6)2 (1), featuring the face-capped octahedral “Re6(μ3-Se)8”2+ cluster core and site-differentiating triethylphosphine and 4-vinylpyridine ligands has been synthesized and structurally characterized. The complex crystallized in monoclinic space group P21 with a=11.748(1)A, b=15.1212(2)A, c=19.941(2)A, α=90°, β=94.411(3)°, γ=90°, V=3531.8(7)A3, Z=2, R1=0.0531, wR2=0.0774. Copolymerization of styrene with 1 via the polymerizable 4-vinylpyridine ligand afforded a novel inorganic-organic hybrid composite of high molecular weight and a low polydispersity index. Structural integrity of the cluster building block is maintained upon hybrid formation.

A series of near-IR emitting organic light-emitting diodes (OLEDs) have been prepared using poly(vinylcarbazole) (PVK) as the hole transport polymer, aluminum quinolate (Alq3) or a sulfonamide derivative (Al(qs)3) as the host dye (H), and phthalocyanine (Pc) or naphthalocyanine (NPc) dopants as guest dyes (G). The separation of the emission spectrum of the guest dye from that of the host dye allows for independent assessment of their relative efficiencies and correlation of these efficiencies with their tendencies toward charge capture and recombination reminiscent of solution electrogenerated chemiluminescent reactions. Although the absorbance spectra of the guest dyes are significantly separated from the emission spectra of the host dyes, the high molar absorptivities of the Pc and NPc dopants lead to Forster radii and relative energy-transfer (ET) efficiencies comparable to values previously obtained for quinacridone or rubrene dopants, which have been used to create intense green or yellow emission in...

The first incorporation of quinacridone, a technologically important organic electroluminescent emitter, into dendrimers increases solubility, decreases aggregation, retards heterogeneous electron transfer, and enhances luminescence in condensed phases (powders and thin films).