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Dengue hemorrhagic fever is one infectious diseases that have high case fatality rate in Indonesia. The aim of this study was to descibe the antibody anti-dengue profile in dengue hemorrhagic fever patients at Dr. Soetomo Hospital Surabaya. This study was epidemiological descriptive study to aims prevalence primary and secondary infection of dengue hemorrhagic fever and its clinical appearances. This study used 85 samples by taking medical record data of IgM and IgG anti-dengue serologic test from Internal Medicine Department, Dr. Soetomo Hospital, Surabaya, between January to December 2010. The data were collected and analyzed in diagrams and tables. Result of this study showed 25 (29,4%) patients had positive IgM serologic test, 14 (16,4%) patients had positive IgG serologic test and 46 (54,2%) patients had positive IgM and IgG serologic test. In primary infections, the history of fever was 3.8±1.2 days; platelet counts 58,6±21,4/ml and bleeding sign 37% of 25 patients. In secondary infections, the history of fever was 4.28±1.15 days; platelet count was 44,17±24,2/ml and bleeding sign 52% of 60 patients. In conclusion, patients with secondary infection have higher prevalence than primary infection. Then in secondary infection had more severe clinical appearance than primary infection.

Author's Abstract, COPYRIGHT 1999, Mineralogical Society of America Khmaralite, Ca(sub 0.04)Mg(sub 5.46)Fe(super 3+)(sub 0.12)Fe(super 2+)(sub 1.87)Al(sub 14.26)Be(sub 1.43)B(sub 0.02)Si(sub 4.80)O(sub 40), is a new mineral cosely related to sapphirine from Khmara Bay, Enderby Land, Antarctica. It occurs in a pegmatite metamorphosed at T>820 degrees C, P>10kbar. The minerals surinamite, musgravite, and sillimanite associated with khmaralite at Casey Bay Saturate it in BeO, and thus its BeO content could be close to the maximum possible. Optically, khmaralite is biaxial (-); at lambda = 589 nm, alpha = 1.725(2), beta = 1.740(2), gamma = 1.741(2) 2V(sub meas) = 34.4 (1.8) degrees, v>r strong, and beta // b. The weak superstructure reported using electron diffraction has been confirmed by single-crystal X-ray diffraction. The superstructure corresponds to a doubling of the a axis in monoclinic sapphirine-2M (P2(sub 1)/c setting) with the following unit-cell parameters: a = 19.800(1), b = 14.371(1), c = 11.254(1) Angstroms, Beta = 125.53(1) degrees, Z = 4, D(sub calc) = 3.61 g/cm(super 3). Using a simplified chemical formula of Mg(sub 5.46)Al(sub 14.28)Fe(sub 2.00)Si(sub 4.80)Be(sub 1.46)O(sub 40), the fully anisotropic structure refinement of all site occupancies, including Al vs Mg and Al vs. Si on the 16 octahedral (M) and 12 tetrahedral (T) sites respectively, establishes that the 2Xa superstructure results primarily from ordering in the doubled (T1 > T6, T7 > T12) tetrahedral chain, which is parallel to the a axis. The strongest contribution comes from Al-Si-Be ordering on the T2 (33-16-51%) vs. T8 (0-95-5%) and T3 (4-78-18%) vs. T9 (30-0-70%) sites. Thus, the sequence Al-Si-Al in sapphirine is replaced by the sequence Si-Be-Si in khmaralite; i.e., Be replaces Si on two sites and Si replaces Al on on four adjacent sites, resulting in an indirect replacement of Al by Be by the coupled substitution Be + Si = 2Al. The Be distribution in khmaralite and the strong preference for Be/Al mixing over Be/Si mixing appear to satisfy the bonding requirements of the bridging O atoms by minimizing the number of Be-O-Be and Be-O-Al linkages.

The crystal structure of philolithite, [Pb.sub.12][O.sub.6]Mn[(Mg,Mn).sub.2][(Mn,Mg).sub.4] ([SO.sub.4])[([CO.sub.3]).sub.4][Cl.sub.4][(OH).sub.12], [P4.sub.2]/nnm, a = 12.627(9), c = 12.595(9) [Angstrom], V = 2008(2) [[Angstrom].sup.3], Z = 2 has been solved by Patterson difference-Fourier syntheses and refined to R = 0.053 for 814 [F.sub.o] [is greater than] 4[Sigma].sub.Fo] using MoK[Alpha] X-ray data. In the structure, Mn[O.sub.6] octahedra form straight chains parallel to [110] and [1 bar] 10] by sharing opposite octahedral edges. Octahedra within the chains are further linked by sharing free corners with Mn[O.sub.4] and [SO.sub.4] tetrahedra and [CO.sub.3] triangles. The Mn[O.sub.4] and [SO.sub.4] tetrahedra also form bridging struts between octahedral chains, connecting them in the [001] direction into an open framework. The Pb, C1, and non-framework O atoms occupy the open spaces within the framework. The 10- and 12-fold coordinations of the Pb atoms exhibit the lone-pair effect. Pb atoms link via short bonds to non-framework O atoms to form chains parallel to [110] and [[bar] 1 10]. When viewed down [111], [[bar] 11 1], [1 [bar] 11], or [[bar] 1 1 [bar] 1], the framework (less the [CO.sub.3] groups) is seen to be based upon cubic closest-packing of anions. This open framework of composition [MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII], referred to as a closest-packed trellis, is the fundamental unit for the structure.

Electrochemical fluorination on nickel anodes, also known as the Simons' process, is an important fluorination method used on an industrial scale. Despite its success, the mechanism is still under debate. One of the proposed mechanisms involves higher valent nickel species formed on an anode acting as effective fluorinating agents. Here we report the first attempt to study fluorination by means of first principles investigation. We have identified a possible surface model from the simplest binary nickel fluoride (NiF 2 ). A twice oxidized NiF 2 (F 2 ) (001) surface exhibits higher valent nickel centers and a fluorination source that can be best characterized as an [F 2 ] - like unit, readily available to aid fluorination. We have studied the adsorption of CH 4 and the co-adsorption of CH 4 and HF on this surface by means of periodic density functional theory. By the adsorption of CH 4 , we found two main outcomes on the surface. Unreactive physisorption of CH 4 and dissociative chemisorption resulting in the formation of CH 3 F and HF. The co-adsorption with the HF gave rise to four main outcomes, namely the formation of CH 3 F, CH 2 F 2 , CH 3 radical, and also physisorbed CH 4 .

The Simons process is an electrochemical fluorination method to prepare organofluorine compounds. Despite the wide application, the underlying mechanism is still unclear. We report the investigation of the black film formed on the surface of the anodes in aHF by an in situ Ni K-edge X-ray absorption near edge structure (XANES) investigation. An electrochemical cell for in situ X-ray absorption spectroscopy (XAS) is presented., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Molecular switches based on functionalized graphene nanoribbons (GNRs) are of great interest in the development of nanoelectronics. In experiment, it was found that a significant difference in the conductance of an anthraquinone derivative can be achieved by altering the pH value of the environment. Building on this, in this work we investigate the underlying mechanism behind this effect and propose a general design principle for a pH based GNR-based switch. The electronic structure of the investigated systems is calculated using density functional theory and the transport properties at the quasi-stationary limit are described using nonequilibrium Green's function and the Landauer formalism. This approach enables the examination of the local and the global transport through the system. The electrons are shown to flow along the edges of the GNRs. The central carbonyl groups allow for tunable transport through control of the oxidation state via the pH environment. Finally, we also test different types of GNRs (zigzag vs. armchair) to determine which platform provides the best transport switchability.

The state-of-the-art density functional theory approach was used to study the structural and electronic properties of pristine and defective MnPX 3 monolayers as well as their activity toward water and hydrogen evolution reaction (HER) catalytic performance. The adsorption behavior of H 2 O on a pristine MnPX 3 structure is of physisorption nature, whereas the adsorption energy is significantly increased for the defective structures. At the same time, the water dissociation process is more energetically favorable, and the reactivity of MnPX 3 is determined by the vacancy configuration. Following Nørskov's approach, the HER catalytic performance is evaluated by calculating the hydrogen adsorption free energy on the respective MnPX 3 surface. Our calculation results demonstrate that defective 2D MnPX 3 with low coordinated P shows significantly higher HER performance compared to the pristine counterpart., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

Weakly coordinating anions (WCAs) have attracted much attention in recent years due to their ability to stabilise highly reactive cations. It may well be argued, however, that a profound understanding of what truly defines a WCA is still lacking, and systematic studies to unravel counterion effects are scarce. In this work, we investigate a supramolecular pseudorotaxane formation reaction, subject to a selection of anions, ranging from strongly to weakly coordinating, which not only aids in fostering our knowledge about anion coordination properties, but also provides valuable theoretical insight into the nature of the mechanical bond. We employ state-of-the-art DFT-based methods and tools, combined with isothermal calorimetry and 1H NMR experiments, to compute anion-dependent Gibbs free association energies ΔGa, as well as to evaluate intermolecular interactions. We find correlations between ΔGa and the anions' solvation energies, which are exploited to calculate physico-chemical reaction parameters in the context of coordinating anions. Furthermore, we show that the binding situation within the (pseudo)rotaxanes can be mostly understood by straight-forward electrostatic considerations. However, quantum-chemical effects such as dispersion and charge-transfer interactions become more and more relevant when WCAs are employed.

The structure and electronic properties of the molybdenum disulfide (MoS 2 ) monolayer upon water cluster adsorption are studied using density functional theory and the optical properties are further analyzed with the Bethe-Salpeter equation (BSE). Our results reveal that the water clusters are electron acceptors, and the acceptor tendency tends to increase with the size of the water cluster. The electronic band gap of both pristine and defective MoS 2 is rather insensitive to water cluster adsorbates, as all the clusters are weakly bound to the MoS 2 surface. However, our calculations on the BSE level show that the adsorption of the water cluster can dramatically redshift the optical absorption for both pristine and defective MoS 2 monolayers. The binding energy of the excitons of MoS 2 is greatly enhanced with the increasing size of the water cluster and finally converges to a value of approximately 1.16 eV and 1.09 eV for the pristine and defective MoS 2 monolayers, respectively. This illustrates that the presence of the water cluster could localize the excitons of MoS 2 , thereby greatly enhance the excitonic binding energy.

Samarium diiodide is a versatile single electron transfer (SET) agent with various applications in organic chemistry. Lewis structures regularly insinuate the existence of a ketyl radical when samarium diiodide binds a carbonyl group. The study presented here investigates this electron transfer by the means of computational chemistry. All electron CASPT2 calculations with the inclusion of scalar relativistic effects predict an endotherm electron transfer from samarium diiodide to acetone. Energies calculated with the PBE0-D3(BJ) functional and a small core pseudopotential are in good agreement with CASPT2. The calculations confirm the experimentally measured increase of the samarium diiodide reduction potential through the addition of hexamethylphosphoramide also known as HMPA.

The trifluorides of the two high field strength elements yttrium and holmium are studied by periodic density functional theory. As a lanthanide, holmium also belongs to the group of rare earth elements (REE). Due to their equivalent geochemical behavior, both elements form a geochemical twin pair and consequently, yttrium is generally associated with the REE as REE+Y. Interestingly, it has been found that DFT/DFT+U describe bulk HoF 3 best, when the 4f-electrons are excluded from the valence region. An extensive surface stability analysis of YF 3 (PBE) and HoF 3 (PBE+Ud/3 eV/4f-in-core) using two-dimensional surface models (slabs) is performed. All seven low-lying Miller indices surfaces are considered with all possible stoichiometric or substoichiometric terminations with a maximal fluorine-deficit of two. This leads to a scope of 24 terminations per compound. The resulting Wulff plots consists of seven surfaces with 5-26% abundance for YF 3 and six surfaces with 6-34% for HoF 3 . The stoichiometric (010) surface is dominating in both compounds. However, subtle differences have been found between these two geochemical twins.

A systematic examination of the electronic and transport properties of 1D fluorine-saturated zigzag graphene nanoribbons (ZGNRs) is presented in this article. One publication (Withers et al., Nano Lett. , 2011 , 11 , 3912-3916.) reported a controlled synthesis of fluorinated graphene via an electron beam, where the correlation between the conductivity of the resulting materials and the width of the fluorinated area is revealed. In order to understand the detailed transport mechanism, edge-fluorinated ZGNRs with different widths and fluorination degrees are investigated. Periodic density functional theory (DFT) is employed to determine their thermodynamic stabilities and electronic structures. The associated transport models of the selected structures are subsequently constructed. The combination of a non-equilibrium Green's function (NEGF) and a standard Landauer equation is applied to investigate the global transport properties, such as the total current-bias voltage dependence. By projecting the corresponding lesser Green's function on the atomic orbital basis and their spatial derivatives, the local current density maps of the selected systems are calculated. Our results suggest that specific fluorination patterns and fluorination degrees have significant impacts on conductivity. The conjugated π system is the dominate electron flux migration pathway, and the edge effect of the ZGNRs can be well observed in the local transport properties. In addition, with an asymmetric fluorination pattern, one can trigger spin-dependent transport properties, which shows its great potential for spintronics applications.

We carried out first-principles calculations to simulate Ag 2 ZnSnS 4 and Ag 2 CdSnS 4 and calculated enthalpies of different plausible structural models (kesterite-type, stannite-type, wurtzkesterite-type, wurtzstannite-type, and GeSb-type) to identify low- and high-pressure phases. For Ag 2 ZnSnS 4 , we predict the following transition: kesterite-type→[8.2GPa]→ GeSb-type. At the transition pressure, the electronic structure changes from semiconducting to metallic. For Ag 2 CdSnS 4 , we cannot decide which of the experimentally observed structures (kesterite-type or wurtzkesterite-type) is the ground-state structure because their energy difference is too small. At 4.7 GPa, however, we predict a transition to the GeSb-type structure with metallic character for both structures. Regarding the sensitivity of the material to disorder, a major drawback for solar cell applications, Ag 2 CdSnS 4 behaves similar to Cu 2 ZnSnS 4 , both showing a high tendency to cationic disorder. In contrast, the disordered structures in Ag 2 ZnSnS 4 are much higher in energy, and therefore, the material is less affected by disorder., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

In this contribution, we present theoretical modeling of the interaction between rare gas matrices and a trifluoride guest anion, as well as its quantitative effect on measured vibrational spectra. Using a combination of coupled-cluster electronic structure calculations and a many-body potential expansion coupled with permutation invariant polynomial fitting and anharmonic vibrational spectrum simulations, we shed light on the origin of the trifluoride matrix effects observed experimentally. The theoretical spectra are found to reproduce accurately the measured data while providing deeper insights into the effects of the guest-host interaction. The investigations reveal that neon can only stabilize trifluoride in hexagonal cavities formed by double vacancies, while argon can host the anion in a variety of cavities ranging from zero to two defects in the matrix. The origin of this structural variability can be traced back to the disparate strengths of the host-host interactions in neon and argon. The present work demonstrates the importance of theoretical modeling to complement matrix isolation experiments, which alone do not provide direct information about the structure of the matrices or about the physical origin of their interaction and of their spectroscopic signature.

During the past decades π-conjugated bi-radicals have attracted increasing attention, due to the existence of two close-in-energy resonant electronic configurations with very distinct characteristics: the open-shell bi-radical and the closed-shell quinoidal. The chemical design of the bi-radical structure has been shown to be very effective to shift the balance towards one, or the other, electronic distribution. Some reports have experimentally studied the analogous 1D oligomers and polymers, however, only the open-shell multi-radical configuration has been detected, and it is yet not very clear which structural and chemical parameters are relevant in such extended systems. In this work, via first principles quantum chemical simulations, we study a series of π-conjugated 1D polymers based on triarylmethyl radicals with different chemical functionalization. We find that dihedral angles of the aryl rings connecting the radical centres are the key conformational parameter determining the electronic balance. This provides a simple recipe to use chemical functionalization of aryl rings as a tool to shift the system towards either the electron paired or unpaired configurations. Additionally, we find such conformational control is also effective under the effect of thermal fluctuations, which highlights its potential technological applicability., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)