The non-Newtonian rheology of dilute colloidal suspensions

The non-Newtonian rheology is calculated numerically to second order in the volume fraction in steady simple shear flows for Brownian hard spheres in the presence of hydrodynamic and excluded volume interactions. Previous analytical and numerical results for the low-shear structure and rheology are confirmed, demonstrating that the viscosity shear thins proportional to Pe2, where Pe is the dimensionless shear rate or Péclet number, owing to the decreasing contribution of Brownian forces to the viscosity. In the large Pe limit, remnants of Brownian diffusion balance convection in a boundary-layer in the compressive region of the flow. In consequence, the viscosity shear thickens when this boundary-layer coincides with the near-contact lubrication regime of the hydrodynamic interaction. Wakes are formed at large Pe in the extensional zone downstream from the reference particle, leading to broken symmetry in the pair correlation function. As a result of this asymmetry and that in the boundary-layer, finite normal stress differences are obtained as well as positive departures in the generalized osmotic pressure from its equilibrium value. The first normal stress difference changes from positive to negative values as Pe is increased when the hard-sphere limit is approached. This unusual effect is caused by the hydrodynamic lubrication forces that maintain particles in close proximity well into the extensional quadrant of the flow. The study demonstrates that many of the non-Newtonian effects observed in concentrated suspensions by experiments and by Stokesian dynamics simulations are present also in dilute suspensions

A survey of tourism management attitudes to renewable energy supply in Primorsko-Goranska county (Croatia)

The paper presents the methodology of a conducted questionnaire survey and the results regarding energy consumption in the tourism of Primorsko-Goranska County (Croatia). The attitudes about energy consumption management and practical aspects concerning consumption are highlighted. The pool consists of three major groups of tourism objects: hotels and related facilities, camping parks and marinas. The plan was to analyze 91 tourism object, but only from 30 objects was achieved the response (33% rate). Largest share of the pool is located in the coastal area (73%), and much smaller shares are in the mountain region (13%) and the islands (13%). The results of analysis show that the largest amount of energy is used for interior heating/cooling (26,0%) and food purposes (24,5%), then for the illumination (17,3%), hot water (17,0%), laundering and ironing (10,4%), cleaning and waste disposal (2,6%) and other (2,1%). The attitudes about saving are emphasized and 96,7% of surveyed managers suppose that it is possible to manage the energy consumption and that energy increasingly influences their sustainable business activities. Information technology equipment for energy consumption control was installed in 16,7% of facilities and only 13,3% of businesses were exploiting renewable energy sources (RES) in 2007

Reductive and Oxidative DNA Damage by Photoactive Platinum(II) Intercalators

Several photoactive platinum R-diimine intercalators have been prepared to develop new probes of DNA oxidation and reduction chemistry. Five water-soluble bis(mes')Pt(II) complexes (mes') N,N,N,3,5-pentamethylaniline) with various aromatic α-diimine ligands (dppz= dipyridophenazine, np = naphtha[2,3-f][1,ω]phenanthroline, CN-np = naphtho[2,3-f][1,10]phenanthroline-9-carbonitrile, CN_2-np = naphtho[2,3-f][1,10]phenanthroline-9,14-dicarbonitrile, and bp = benzo-[f][1,10]phenanthroline) were synthesized. The complex [(np)Pt(mes')_2]Cl_2 was also characterized by X-ray crystallography, and the crystal structure shows that the ortho-methyl groups of the mes' ligands conveniently block substitution at the vacant sites of platinum without overlapping with the intercalating α-diimine ligand. The Pt(II) complexes were found to have excited-state oxidation and reduction potentials of -0.6 to -1.0 and 1.0 to 1.5 V versus NHE, respectively, making them potent photoreductants as well as photooxidants. Many of the complexes are found to promote the photooxidation of N^2-cyclopropyldeoxyguanosine (d^(Cp)G). Photoexcited [(dppz)Pt(mes')_2]^(2+) is found to be most efficient in this photooxidation, as well as in the photoreduction of N^4-cyclopropylcytidine (^(Cp)C); these modified nucleosides rapidly decompose in a ring-opening reaction upon oxidation or reduction. Photoexcited [(dppz)Pt(mes')_2]Cl_2, upon intercalation into the DNA π stack, is found, in addition, to promote reductive and oxidative damage within the DNA duplex, as is also probed using the kinetically fast electron and hole traps, ^(Cp)C and ^(Cp)G. These Pt complexes may therefore offer useful reactive tools to compare and contrast directly reductive and oxidative chemistry in double helical DNA

Electoral officials can do little to combat information which undermines elections

As the 2020 presidential election approaches, there is growing concern over disinformation about the electoral process which may work to undermine the legitimacy of the election’s outcome. In new research, Brian Calfano, Richard Harknett, Gregory Winger, and Jelena Vicic surveyed nearly 9,000 Americans to determine the effect of messaging from Secretaries of State to counter disinformation. They find that attempts to correct disinformation by Secretaries of State about elections are generally ineffective, regardless of whether someone is a Republican or Democratic voter

Reporting government reactions to claims of electoral fraud can help maintain public trust in the media.

The 2020 US Presidential election campaigns have raised questions about the media and its credibility among US citizens. While many view the media as an important part of democracy, there is also an awareness of its role in furthering political divisions. Brian Calfano, Richard Harknett, Gregory Winger and Jelena Vicic examine the crucial relationship between the government and the media, and its broader implications for restoring faith in election coverage

ANTENATAL DETECTION OF CHROMOSOMAL ABNORMALITIES COMBINING QF-PCR AND CYTOGENETIC ANALYSIS

Aim: To compare the diagnostic values and limitations of quantitative fluorescent polymerase chain reaction (QF-PCR) and conventional cytogenetic analysis in prenatal diagnosis of chromosomal abnormalities. Methods: A prospective study included simultaneous QF-PCR and cytogenetic analysis of 133 prenatal samples routinely obtained by amniocentesis or chorionic villus sampling (CVS). Additionally, QF-PCR analysis was performed on 14 tissue samples collected after termination of pregnancy (TOP) for which karyotyping could not be performed due to culture failure. Results: Among 133 analyzed prenatal samples, chromosomal abnormalities were diagnosed in 12 cases (9%), including 10 cases of numerical chromosomal aberrations and two cases with unbalanced structural rearrangements. Nine out of 12 chromosomal abnormalities were also detected with QF-PCR. However, all cases of major aneuploidies were successfully disclosed with QF-PCR, resulting in 100% detection rate for chromosomes 21, 18, 13, X and Y. Using a set of markers specific for chromosomes 21, 18 and 13, QF-PCR analysis of tissues collected after TOP revealed chromosomopathy in 21.4% of cases (two cases of trisomy 18 and one triploidy). A comparison of STR markers confirmed monozygosity in two monochorionic/diamniotic twin pregnancies. Conclusion: QF-PCR has been shown as a rapid and reliable method for prenatal diagnosis of the most common chromosomal aneuploidies, and as an adequate alternative to conventional karyotyping in cases where cytogenetic analysis is not possible due to failure of culturing process. However, conventional cytogenetics still presents a gold standard for the detection of structural aberrations and rare aneuploidies

Seasonal influenza vaccine performance and the potential benefits of mRNA vaccines

Influenza remains a public health threat, partly due to suboptimal effectiveness of vaccines. One factor impacting vaccine effectiveness is strain mismatch, occurring when vaccines no longer match circulating strains due to antigenic drift or the incorporation of inadvertent (eg, egg-adaptive) mutations during vaccine manufacturing. In this review, we summarize the evidence for antigenic drift of circulating viruses and/or egg-adaptive mutations occurring in vaccine strains during the 2011-2020 influenza seasons. Evidence suggests that antigenic drift led to vaccine mismatch during four seasons and that egg-adaptive mutations caused vaccine mismatch during six seasons. These findings highlight the need for alternative vaccine development platforms. Recently, vaccines based on mRNA technology have demonstrated efficacy against SARS-CoV-2 and respiratory syncytial virus and are under clinical evaluation for seasonal influenza. We discuss the potential for mRNA vaccines to address strain mismatch, as well as new multi-component strategies using the mRNA platform to improve vaccine effectiveness

[1,2-Bis­(diisopropyl­phosphan­yl)ethane-κ2 P,P′]dichloridonickel(II)

In the crystal structure of title compound, [NiCl2(C14H32P2)], the NiII atom lies on a twofold rotation axis and shows a slightly distorted square-planar coordination geometry, with a dihedral angle of 10.01 (8)° between the cis-Cl—Ni—Cl and cis-P—Ni—P planes. There is no significant inter­molecular inter­action except very weak C—H⋯Cl inter­actions. The crystal studied was a racemic twin

[1,2-Bis­(diisopropyl­phosphan­yl)ethane-κ2 P,P′]dichloridonickel(II)–9H-carbazole (1/2)

In the title compound, [NiCl2(C14H32P2)]·2C12H9N, the neutral [Ni(dppe)Cl2] complex [dppe is 1,2-bis­(diisopropyl­phosphan­yl)ethane] consists of a tetracoordinated Ni2+ cation and has a crystallographic twofold axis passing through the metal atom and the mid-point of the CH2—CH2 bond of the dppe ligand. The metal atom shows slight tetra­hedral distortion from an ideal square-planar coordination geometry, as reflected in the dihedral angle between NiCl2 and NiP2 planes of 15.32 (2)°. The 9H-carbazole ring system is essentially planar (r.m.s. deviation = 0.022 Å). In the crystal packing, there are two symmetry-related 9H-carbazole mol­ecules between two adjacent NiII complexes, with an angle between the carbazole mean planes of ca 77°

Inhibition of DNA Methylation Alters Chromatin Organization, Nuclear Positioning and Activity of 45S rDNA Loci in Cycling Cells of Q. robur

Around 2200 copies of genes encoding ribosomal RNA (rRNA) in pedunculate oak, Quercus robur, are organized into two rDNA loci, the major (NOR-1) and the minor (NOR-2) locus. We present the first cytogenetic evidence indicating that the NOR-1 represents the active nucleolar organizer responsible for rRNA synthesis, while the NOR-2 probably stays transcriptionally silent and does not participate in the formation of the nucleolus in Q. robur, which is a situation resembling the well-known phenomenon of nucleolar dominance. rDNA chromatin topology analyses in cycling root tip cells by light and electron microscopy revealed the minor locus to be highly condensed and located away from the nucleolus, while the major locus was consistently associated with the nucleolus and often exhibited different levels of condensation. In addition, silver precipitation was confined exclusively to the NOR-1 locus. Also, NOR-2 was highly methylated at cytosines and rDNA chromatin was marked with histone modifications characteristic for repressive state. After treatment of the root cells with the methylation inhibitor 5-aza-2'-deoxycytidine, we observed an increase in the total level of rRNA transcripts and a decrease in DNA methylation level at the NOR-2 locus. Also, NOR-2 sites relocalized with respect to the nuclear periphery/nucleolus, however, the relocation did not affect the contribution of this locus to nucleolar formation, nor did it affect rDNA chromatin decondensation, strongly suggesting that NOR-2 has lost the function of rRNA synthesis and nucleolar organization