Vertically aligned Mn (10%)-doped Fe 3 O 4 (Fe 2.7 Mn 0.3 O 4 ) nanowire arrays were produced by the reduction/ substitution of pregrown Fe 2 O 3 nanowires. These nanowires were ferromagnetic with a Verwey temperature of 129 K. X-ray magnetic circular dichroism measurements revealed that the Mn 2+ ions preferentially occupy the tetrahedral sites, substituting for the Fe 3+ ions. We observed that the Mn substitution decreases the magnetization, but increases the electrical conductivity. We developed highly sensitive gas sensors using these nanowire arrays, operating at room temperature, whose sensitivity showed a correlation with their bond strength of diatomic/triatomic molecules.

A series of hybrid inorganic-organic copper(II) hydroxy n-alkylsulfonate with a triangular lattice, Cu(2)(OH)(3)(C(n)H(2)(n)(+1)SO(3)) (n = 6, 8, 10), are prepared by anion exchange, starting from copper hydroxy nitrate Cu(2)(OH)(3)NO(3). These compounds show a layered structure as determined by X-ray diffraction, with interlayer distances of 14.3-34.8 A in alternation with interdigitated bilayer packing. Magnetic properties have been investigated by means of dc and ac measurements. All the compounds show similar metamagnet behaviors, with a Neel temperature of about 11 K. A subtle difference in the ac magnetic susceptibility among the compounds is understood by the existence of hydrogen bonding between the sulfonate headgroup and the hydroxide anion. A detailed molecular structure of the alkyl chains incorporated to the inorganic copper hydroxide layer is also discussed from the FTIR data.

Direct characterization of chain molecular structures in a series of layered organic/inorganic longchain alkylsulfonates, Cu(C n H 2n+1 SO 3 ) 2 ‚yH 2 O (CuSO 3 -n, where n)10, 12 and y ) 4 for group I; n ) 14, 16, 18 and y ) 2 for group II), using combined application of Fourier transform infrared (FTIR) spectroscopy and powder X-ray diffraction (XRD) is reported. These compounds show a layered structure, as determined by XRD, consisting of alternating organic alkylsulfonate layers and inorganic copper(II) hydrate layers, with interlayer distances of up to 3.82 nm. It is worth noting that the layer-to-layer distance can be easily and rationally metered by choosing alkylsulfonates of different lengths: Shorter alkylsulfonates, group I, yield an interdigitated monolayer structure with shorter periodicity, whereas longer alkylsulfonates, group II, yield a noninterdigitated bilayer structure with longer periodicity. The goal was to correlate the structural changes by increasing the chain length, monitored by XRD, with the alkyl chain structure detected by FTIR spectroscopy. From the FTIR spectra, the distinguishable features between the two groups appear in two different wavenumber regions, i.e., the hydrogen-bonding region (2900-3500 cm -1 ) and the sulfonate-stretching region (1000-1250 cm -1 ), indicating that the hydrophilic layers of the two groups are completely different. Furthermore, a detailed investigation of the C-H modes, including the stretching, scissoring, and rocking modes, reveals that the chain-packing modes of the two groups are different, even though the alkyl chains in the CuSO 3 -n series are all in an all-trans conformational state. The change in the monolayer to bilayer packing with the alkyl chain length, arising from the intermolecular interaction between the alkyl chains, is explained by the rearrangement of the alkyl chains from orthorhombic to hexagonal subcells with decreasing packing density.

Background A vaccine against COVID-19 has been developed; however, COVID-19 transmission continues. Although there have been many studies of comorbidities that have important roles in COVID-19, some studies have reported contradictory results. Objective This study was conducted using real-world data from COVID-19 patients in South Korea and aimed to investigate the impact of patient demographics and comorbidities on the infection rate and severity of COVID-19. Methods Data were derived from a nationwide South Korean COVID-19 cohort study with propensity score (PS) matching. We included infected individuals who were COVID-19–positive between January 1, 2020, and May 30, 2020, and PS-matched uninfected controls. PS matching was performed to balance the baseline characteristics of each comorbidity and to adjust for potential confounders, such as age, sex, Charlson Comorbidity Index, medication, and other comorbidities, that were matched with binary variables. The outcomes were the confirmed comorbidities affecting the infection rate and severity of COVID-19. The endpoints were COVID-19 positivity and severe clinical outcomes of COVID-19 (such as tracheostomy, continuous renal replacement therapy, intensive care unit admission, ventilator use, cardiopulmonary resuscitation, and death). Results The COVID-19 cohort with PS matching included 8070 individuals with positive COVID-19 test results and 8070 matched controls. The proportions of patients in the severe group were higher for individuals 60 years or older (severe clinical outcomes for those 60 years or older, 16.52%; severe clinical outcomes for those of other ages, 2.12%), those insured with Medicaid (Medicaid, 10.81%; other insurance, 5.61%), and those with disabilities (with disabilities, 18.26%; without disabilities, 5.07%). The COVID-19 infection rate was high for patients with pulmonary disease (odds ratio [OR] 1.88; 95% CI 1.70-2.03), dementia (OR 1.75; 95% CI 1.40-2.20), gastrointestinal disease (OR 1.74; 95% CI 1.62-1.88), stroke (OR 1.67; 95% CI 1.23-2.27), hepatobiliary disease (OR 1.31; 95% CI 1.19-1.44), diabetes mellitus (OR 1.28; 95% CI 1.16-1.43), and cardiovascular disease (OR 1.20; 95% CI 1.07-1.35). In contrast, it was lower for individuals with hyperlipidemia (OR 0.73; 95% CI 0.67-0.80), autoimmune disease (OR 0.73; 95% CI 0.60-0.89), and cancer (OR 0.73; 95% CI 0.62-0.86). The severity of COVID-19 was high for individuals with kidney disease (OR 5.59; 95% CI 2.48-12.63), hypertension (OR 2.92; 95% CI 1.91-4.47), dementia (OR 2.92; 95% CI 1.91-4.47), cancer (OR 1.84; 95% CI 1.15-2.94), pulmonary disease (OR 1.72; 95% CI 1.35-2.19), cardiovascular disease (OR 1.54; 95% CI 1.17-2.04), diabetes mellitus (OR 1.43; 95% CI 1.09-1.87), and psychotic disorders (OR 1.29; 95% CI 1.01-6.52). However, it was low for those with hyperlipidemia (OR 0.78; 95% CI 0.60-1.00). Conclusions Upon PS matching considering the use of statins, it was concluded that people with hyperlipidemia could have lower infection rates and disease severity of COVID-19.

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