Search

Background: A viral infection can modify the risk to subsequent viral infections via cross‐protective immunity, increased immunopathology, or disease‐driven behavioral change. There is limited understanding of virus–virus interactions due to lack of long‐term population‐level data. Methods: Our study leverages passive surveillance data of 10 human acute respiratory viruses from Beijing, Chongqing, Guangzhou, and Shanghai collected during 2009 to 2019: influenza A and B viruses; respiratory syncytial virus A and B; human parainfluenza virus (HPIV), adenovirus, metapneumovirus (HMPV), coronavirus, bocavirus (HBoV), and rhinovirus (HRV). We used a multivariate Bayesian hierarchical model to evaluate correlations in monthly prevalence of test‐positive samples between virus pairs, adjusting for potential confounders. Results: Of 101,643 lab‐tested patients, 33,650 tested positive for any acute respiratory virus, and 4,113 were co‐infected with multiple viruses. After adjusting for intrinsic seasonality, long‐term trends and multiple comparisons, Bayesian multivariate modeling found positive correlations for HPIV/HRV in all cities and for HBoV/HRV and HBoV/HMPV in three cities. Models restricted to children further revealed statistically significant associations for another ten pairs in three of the four cities. In contrast, no consistent correlation across cities was found among adults. Most virus–virus interactions exhibited substantial spatial heterogeneity. Conclusions: There was strong evidence for interactions among common respiratory viruses in highly populated urban settings. Consistent positive interactions across multiple cities were observed in viruses known to typically infect children. Future intervention programs such as development of combination vaccines may consider spatially consistent virus–virus interactions for more effective control. [ABSTRACT FROM AUTHOR]

Nationwide prospective surveillance of all-age patients with acute respiratory infections was conducted in China between 2009‒2019. Here we report the etiological and epidemiological features of the 231,107 eligible patients enrolled in this analysis. Children <5 years old and school-age children have the highest viral positivity rate (46.9%) and bacterial positivity rate (30.9%). Influenza virus, respiratory syncytial virus and human rhinovirus are the three leading viral pathogens with proportions of 28.5%, 16.8% and 16.7%, and Streptococcus pneumoniae, Mycoplasma pneumoniae and Klebsiella pneumoniae are the three leading bacterial pathogens (29.9%, 18.6% and 15.8%). Negative interactions between viruses and positive interactions between viral and bacterial pathogens are common. A Join-Point analysis reveals the age-specific positivity rate and how this varied for individual pathogens. These data indicate that differential priorities for diagnosis, prevention and control should be highlighted in terms of acute respiratory tract infection patients' demography, geographic locations and season of illness in China. China operates a national surveillance program for acute respiratory infections and sampled over 200,000 patients between 2009–2019. Here, the authors present results from this program and describe patterns by age, pathogen type, presence of pneumonia, and season. [ABSTRACT FROM AUTHOR]

The synthesis and characterization of two copper(II) complexes, [Cu(deen)[subscript 2]](BF4)[subscript 2] and [Cu(deen)[subscript 2]](NO[subscript 3])[subscript 2] (deen = N,N-diethylethylenediamine), that show interesting thermochromic properties, are described. The subtle alternation of coordination geometry around Cu(II) is responsible for the color change from red to violet. This experiment is suitable for first-year chemistry students and could demonstrate one of the colorful properties of chelate compounds. (Contains 1 scheme and 2 figures.)

Two compounds, K[subscript 2][Cu(C[subscript 2]O[subscript 4])[subscript 2]] times 4H[subscript 2]O, 1, and K[subscript 2][Cu(C[subscript 2]O[subscript 4])[subscript 2]] times 2H[subscript 2]O, 2, were synthesized under controlled conditions. By controlling the concentration of the reaction solutions, it is possible to isolate a kinetic product 1 and a thermodynamic product 2. Of interest is that the tetrahydrate compound can be converted to the dihydrate analogue by partial dehydration either in the solid state or in solution. This illustrates the fact that reactions can proceed via two routes, which can be a difficult concept for students to understand. (Contains 2 figures.)

We herein report the synthesis, crystal structure and magnetic properties of nine new heterotrimetallic complexes. [Ni(Me2valpn)] (H2Me2valpn = N,N′-bis(3-methoxysalicylidene)-2,2-dimethyl-1,3-diaminopropane) was used as the precursor to construct phenoxo-bridged [Ni2Ln]3+ (Ln3+ = Dy, Tb, Gd and Y) species that were respectively connected by two [M(CN)6]3− (M = Cr, Fe or Co) anions to form octanuclear cyclic complexes, i.e. {[Ni(Me2valpn)]2Ln(H2O)M(CN)6}2 in which Ln = Y, Gd, Tb and Dy and M = Cr, Fe or Co (1–9). Each of the complexes contains many lattice-bound molecules of solvation. The Ni(ii) ions are penta-coordinate, while the Ln(iii) ions are nine coordinated with a muffin geometry. The fitting to the χmT vs. T curves of complexes 6–9 gave the parameters of JNiCr = 11.82 cm−1, JNiGd = 0.94 cm−1 and g = 2.04 for complex 6, JNiFe = 10.58 cm−1, JNiGd = 1.24 cm−1 and g = 2.03 for complex 7, JNiCr = 9.4(1) cm−1, zJ′ = −0.050(2) cm−1 and g = 2.06(1) for complex 8 and JNiFe = 4.9(7) cm−1, zJ′ = −0.35(2) cm−1 and g = 2.24(1) for complex 9, respectively. The dynamic magnetic investigations demonstrate that complexes 1–5 display single-molecule magnet properties with an effective energy barrier (Ueff) of 38.9 K (1, M1 = Dy, M2 = Cr), 37.2 K (2, M1 = Dy, M2 = Cr), 24.4 K (3, M1 = Dy, M2 = Co), 21.9 K (4, M1 = Tb, M2 = Cr) and 29.6 K (5, M1 = Tb, M2 = Fe), respectively. Complex 1 shows the highest energy barrier among the octanuclear [Ni4LnM2] (Ln = Dy or Tb, M = Fe, Cr, Co or W) system. Although the [Ni4Dy2Cr2] complexes have Ueff higher than that of [Ni4Dy2Fe2], complex [Ni4TbCr2] shows lower Ueff than that of [Ni4TbFe2]. The results indicate that besides the M–C≡N–Ni magnetic coupling the lanthanide ions can significantly affect the magnetic performances of heterotrimetallic SMMs as well. Moreover, the SMMs are achieved when diamagnetic Co(iii) was substituted by paramagnetic Cr(iii) or Fe(iii) in the [Ni4Tb2 M2] system, suggesting that the trimetallic strategy is effective in the construction of new 3d–4f SMMs. [ABSTRACT FROM AUTHOR]

New heterotrimetallic complexes [Cu(valpn)(H2O)Ln(H2O)3Fe(CN)6]·xH2O (Ln = Gd, x = 3 for complex 1; Ln = Tb, x = 3 for complex 2; Ln = Dy, x = 1.75 for complex 3; H2valpn = N,N′-bis(3-methoxysalicylidene)-1,3-diaminopropane), {[Cu(Me2valpn)]2Ln(H2O)Fe(CN)6·xH2O·yCH3CN}n (Ln = Gd, x = 5, y = 2.5 for complex 4; Ln = Tb, x = 4.5, y = 1.5 for complex 5; Ln = Dy, x = 5.5, y = 2.5 for complex 6; Ln = Y, x = 6, y = 4 for complex 7; H2Me2valpn = N,N′-bis(3-methoxysalicylidene)-2,2-dimethyl-1,3-diaminopropane) have been synthesised by a reaction of Cu(valpn) (or Cu(Me2valpn)), Ln3+ and [Fe(CN)6]3− in a molar ratio of 2 : 1 : 1. Complexes 1–3 have a CuLnFe trinuclear structure, consisting of phenoxo-bridged Cu–Ln and cyano-bridged Ln–Fe moieties. Complexes 4–7 contain phenoxo-bridged Cu2Ln units that are connected by [Fe(CN)6]3− to form a one-dimensional (1D) zig-zag structure. In the trinuclear complexes 1–3, the [Fe(CN)6]3− anion coordinates to Ln3+, whereas it coordinates to Cu2+ in complexes 4–7. Magnetic studies demonstrate that there exists a ferromagnetic interaction between Cu(ii) and Gd(iii) ions via the phenoxo bridges, while the cyano-bridges transit antiferromagnetic coupling between low-spin Fe(iii) and Cu(ii) or Gd(iii). The fitting to the magnetic susceptibilities of complexes 1 and 4 gave the parameters of JCuGd = 2.392 and 2.945 cm−1, and JFeGd = −0.341 cm−1 and JFeCu = −0.378 cm−1. The ac magnetic measurements reveal that complex 6 shows slow magnetization relaxation with an energy barrier of 12.3 K and a relaxation time of τ0 = 1.65 × 10−6 s, which is typical of a single-chain magnet. [ABSTRACT FROM AUTHOR]