Multisensory-inspired modeling and neural correlates for two key binocular interactions.

Most binocular vision models assume that the two eyes sum incompletely. However, some facilitatory cortical neurons fire for only one eye, but amplify their firing rates if both eyes are stimulated. These 'binocular gate' neurons closely resemble subthreshold multisensory neurons. Binocular amplification for binocular gate neurons follows a power law, with a compressive exponent. Unexpectedly, this rule also applies to facilitatory true binocular neurons; although driven by either eye, binocular neurons are well modeled as gated amplifiers of their strongest monocular response, if both eyes are stimulated. Psychophysical data follows the same power law as the neural data, with a similar exponent; binocular contrast sensitivity can be modeled as a gated amplification of the more sensitive eye. These results resemble gated amplification phenomena in multisensory integration, and other non-driving modulatory interactions that affect sensory processing. Models of incomplete summation seem unnecessary for V1 facilitatory neurons or contrast sensitivity. However, binocular combination of clearly visible monocular stimuli follows Schrödinger's nonlinear magnitude-weighted average. We find that putatively suppressive binocular neurons closely follow Schrödinger's equation. Similar suppressive multisensory neurons are well documented but seldom studied. Facilitatory binocular neurons and mildly suppressive binocular neurons are likely neural correlates of binocular sensitivity and binocular appearance respectively.

Malaria trends in districts that were targeted and not-targeted for seasonal malaria chemoprevention in children under 5 years of age in Guinea, 2014-2021.

BACKGROUND: Seasonal malaria chemoprevention (SMC) is a main intervention to prevent and reduce childhood malaria. Since 2015, Guinea has implemented SMC targeting children aged 3-59 months (CU5) in districts with high and seasonal malaria transmission. OBJECTIVE: We assessed the programmatic impact of SMC in Guinea's context of scaled up malaria intervention programming by comparing malaria-related outcomes in 14 districts that had or had not been targeted for SMC. METHODS: Using routine health management information system data, we compared the district-level monthly test positivity rate (TPR) and monthly uncomplicated and severe malaria incidence for the whole population and disaggregated age groups (<5 years and ≥5 years of age). Changes in malaria indicators through time were analysed by calculating the district-level compound annual growth rate (CAGR) from 2014 to 2021; we used statistical analyses to describe trends in tested clinical cases, TPR, uncomplicated malaria incidence and severe malaria incidence. RESULTS: The CAGR of TPR of all age groups was statistically lower in SMC (median=-7.8%) compared with non-SMC (median=-3.0%) districts. Similarly, the CAGR in uncomplicated malaria incidence was significantly lower in SMC (median=1.8%) compared with non-SMC (median=11.5%) districts. For both TPR and uncomplicated malaria incidence, the observed difference was also significant when age disaggregated. The CAGR of severe malaria incidence showed that all age groups experienced a decline in severe malaria in both SMC and non-SMC districts. However, this decline was significantly higher in SMC (median=-22.3%) than in non-SMC (median=-5.1%) districts for the entire population, as well as both CU5 and people over 5 years of age. CONCLUSION: Even in an operational programming context, adding SMC to the malaria intervention package yields a positive epidemiological impact and results in a greater reduction in TPR, as well as the incidence of uncomplicated and severe malaria in CU5.

Color Vision Testing, Standards, and Visual Performance of the U.S. Military.

INTRODUCTION: Color vision deficiency (CVD) is a disqualifying condition for military special duty occupations. Color vision testing and standards vary slightly among the U.S. military branches. Paper-based pseudoisochromatic plates (PIPs) remain a screening tool. Computer-based color vision tests (CVTs), i.e., the Cone Contrast Test (CCT), the Colour Assessment and Diagnosis (CAD) test, and the Waggoner Computerized Color Vision Test (WCCVT), are now replacing the Farnsworth Lantern Test (FALANT) and its variants to serve as a primary or secondary test in the U.S. Armed Forces. To maintain consistency in recruitment, performance, and safety, the study objectives were to examine military color vision testing, passing criteria, and color discrimination performance. METHODS: Study participants were 191 (17% female) students, faculty, and staff of the U.S. Air Force Academy and the Naval Aerospace Medical Institute. All subjects performed six CVTs, and 141 participants completed two additional military relevant color discrimination tasks. Friedman non-parametric test and Wilcoxon signed-rank post hoc test with Bonferroni adjusted P values were used to compare CVTs and standards. Analysis of variance and Bonferroni adjusted post hoc test were used to describe effects on color discrimination performance. RESULTS: The Heidelberg Multicolor-Moreland and Rayleigh (HMC-MR) anomaloscope diagnosed 58 CVD (30.4%). There were no statistically significant differences in identifying red-green CVD by the HMC-MR, CCT, CAD, WCCVT, and PIP tests (P = .18), or classifying deutan, protan, and normal color vision (CVN) by the HMC-MR and the CVT (P = .25). Classification of tritan CVD was significantly different depending on which CVT was used (P < .001). Second, overall passing rates were 79.1% on the CAD (≤6 standard normal unit (SNU)), 78.5% on the combined PIP/FALANT, 78.0% on the CCT (≥55%), and 75.4% on the WCCVT (mild) military standards. The CVTs and the PIP/FALANT standards were not significantly different in number of personnel selected, but CAD and CCT passed significantly more individuals than WCCVT (P = .011 and P = .004, respectively). The previous U.S. Air Force standard (CCT score ≥75%) passed significantly fewer individuals relative the U.S. Navy pre-2017 PIP/FALANT or the current CVT standards (P ≤ .001). Furthermore, for those who failed the PIP (<12/14), the FALANT (9/9 or ≥16/18) agreed with the CVTs on passing the same CVN (n = 5); however, it also passed moderate-to-severe CVD who did not pass WCCVT (n = 6), CCT (n = 3), and CAD (n = 1). Lastly, moderate/severe CVD were significantly slower and less accurate than the "mild" CVD or CVN in the two color discrimination tasks (P < .001). In comparison to CVN in the in-cockpit display color discrimination task, mild CVD (CCT ≥55% and <75%) were significantly slower by 1,424 ± 290 milliseconds in reaction time (P < .001) while maintaining accuracy. CONCLUSIONS: CVTs are superior to paper-based PIP in diagnosing, classifying, and grading CVD. Relative to the PIP/FALANT standard in personnel selection, the current U.S. military CVT passing criteria offer comparable passing rates but are more accurate in selecting mild CVD. Nevertheless, military commanders should also consider specific operational requirements in selecting mild CVD for duty as reduced job performance may occur in a complex color critical environment.

Folded metallodendrons: shell-selective metal coordination and conformational properties.

The synthesis, structure, and conformational properties of folded metallodendrons are described. The enhanced coordination ability of oxazoline-functionalized pyridyl-2,6-dicarboxamides, compared with pyridyl-2.6-diarylamides, permits unique metals to be installed at the peripheral and focal shells of the dendron. Circular dichroism (CD) studies and X-ray crystallography indicate that the intrinsic helical preference of the parent dendron is not perturbed by coordination. However, the CD spectra become insensitive to temperature due to an increase in structural rigidity that occurs upon metal coordination. [structure: see text]

Structural impact of coordinating a helical 2,6-pyridyl diamide with divalent metals.

[Structure: see text] The structural consequences of coordinating 2,6-bis[2-((4S)-4-methyl-4,5-dihydro-1,3-oxazol-2-yl)phenyl]carbamoylpyridines, 2, with divalent metals such as Cu(II), Ni(II), and Zn(II) are reported. Metal coordination occurs under mild conditions in a manner that preserves the helical bias of the parent ligand in the solid state and in solution. 1H NMR line-shape analysis indicates that metal coordination increases the helical interconversion barrier, thus rigidifying the dynamic helicity of 2.

Synthesis and selected reactions of a bicyclic sultam having sulfur at the apex position.

A practical synthesis of the bicyclic dienyl sultam 9 has been developed. The viable route involved several key steps. Of these, ring-closing metathesis represented by the conversion of 19 to 20 had to be implemented in advance of the assembly of other rings such as is present in 15. Product 20 was used as the template for more advanced framework construction, as in 16. The second double bond was best introduced by a bromination-dehydrobromination sequence, the 2-fold loss of HBr being achieved most reliably by the use of tetra-n-butylammonium fluoride in CH2Cl2 or DMSO. The direct irradiation of 9 gave rise to the endo-oriented cyclobutene derivative 30. The title diene is not a ready participant in Diels-Alder reactions. When heated with endo-bornyltriazolinedione in ethyl acetate solution, conversion to a 1:1 mixture of 33 and its diastereomer occurred as confirmed by X-ray crystallographic analysis. From the mechanistic perspective, this transformation constitutes an interesting example of a stereocontrolled and regioselective [2+2] cycloaddition followed by a vinylcyclobutane-cyclohexene rearrangement. Products 30 and 33 constitute examples of strained sulfonamides featuring a norbornyl-like structural component.

The influence of sterics on the formation of polar 1-D hydrogen-bonded networks.

Polar, noncentrosymmetric packing of directional, 1-D hydrogen-bonded networks of chiral, 4-amino-2,6-bis(oxazolinyl)pyridines (ampybox) occurs for isopropyl-substituted ampybox; in contrast, 1-D networks of methyl-substituted ampybox pack in an antiparallel arrangement.

Dynamic helical chirality of an intramolecularly hydrogen-bonded bisoxazoline.

The synthesis and conformational properties of 2,6-bis-[2-((4S)-4-methyl-4,5-dihydro-1,3-oxazol-2-yl)phenyl]carbam oylpyridines, 2, have been described. Bisoxazoline 2a was prepared in five steps from 2-nitrobenzoyl chloride in an overall yield of 71%. In contrast to related structures such as 1, bisoxazoline 2a exhibits a highly biased P-type helical conformation in solution and in the solid state. In the crystal lattice, 2a further assembles into a left-handed helical superstructure aligned along the crystallographic c axis. The barrier to helical interconversion, as measured by line-shape analysis of the temperature-dependent (1)H NMR spectra of thiobenzyl derivative 2b, was determined to be quite low ((Delta)G(++) = 12.3 kcal/mol), indicating the presence of a highly dynamic helical chirality.