Phylogenetic Complexity of Morphologically Identified Anopheles squamosus in Southern Zambia

Despite dramatic reductions in malaria cases in the catchment area of Macha Hospital, Choma District, Southern Province in Zambia, prevalence has remained near 1-2% by RDT for the past several years. To investigate residual malaria transmission in the area, this study focuses on the relative abundance, foraging behavior, and phylogenetic relationships of Anopheles squamosus specimens. In 2011, higher than expected rates of anthropophily were observed among "zoophilic" An. squamosus, a species that had sporadically been found to contain Plasmodium falciparum sporozoites. The importance of An. squamosus in the region was reaffirmed in 2016 when P. falciparum sporozoites were detected in numerous An. squamosus specimens. This study analyzed Centers for Disease Control (CDC) light trap collections of adult mosquitoes from two collection schemes: one performed as part of a reactive-test-and-treat program and the second performed along a geographical transect. Morphological identification, molecular verification of anopheline species, and blood meal source were determined on individual samples. Data from these collections supported earlier studies demonstrating An. squamosus to be primarily exophagic and zoophilic, allowing them to evade current control measures. The phylogenetic relationships generated from the specimens in this study illustrate the existence of well supported clade structure among An. squamosus specimens, which further emphasizes the importance of molecular identification of vectors. The primarily exophagic behavior of An. squamosus in these collections also highlights that indoor vector control strategies will not be sufficient for elimination of malaria in southern Zambia.

1169Interim analysis of data from a long-term, extension trial of tafamidis meglumine in patients with transthyretin amyloid cardiomyopathy

Background

Transthyretin amyloid cardiomyopathy (ATTR-CM), is an underdiagnosed, fatal disease caused by the deposition of transthyretin amyloid fibrils in the heart leading to heart failure. The Transthyretin Cardiomyopathy Clinical Trial (ATTR-ACT), an international, multi-center, double-blind, placebo-controlled, randomized study, demonstrated the efficacy and safety of tafamidis treatment for patients with ATTR-CM due to variant (ATTRm) or wild-type (ATTRwt) TTR.

Purpose

This is a pooled analysis of data from ATTR-ACT and interim data from the ongoing, long-term, extension study to evaluate longer term data on the efficacy of tafamidis in patients with ATTR-CM.

Methods

Patients who completed ATTR-ACT (which had a duration of 30 months) were eligible to be enrolled in a long-term, extension study in which patients either continued to receive tafamidis meglumine at the same dose (the tafamidis/tafamidis [T/T] group) or, for patients previously treated with placebo, were randomised (in a 1:2 ratio) to tafamidis meglumine 20 mg or 80 mg (the placebo/tafamidis [P/T] group) for up to 60 months. The primary efficacy outcome was all-cause mortality. This analysis combined data from the completed ATTR-ACT with interim data from the extension study (cut-off date: 15 Feb, 2018), and included patients treated with tafamidis meglumine across the two studies with a median follow up of 36 months.

Results

All-cause mortality was significantly lower in the T/T group (n=264; 88 events, 33.3%) compared with the P/T group (n=177; 88 events, 50.3%); hazard ratio (95% CI), 0.64 (0.47, 0.85); P=0.001. In the subgroup of ATTRwt patients, all-cause mortality was significantly reduced in the T/T group (55/201; 27.4%) compared with the P/T group (60/134; 44.8%); 0.64 (0.44, 0.92); P=0.002. In the 106 (24.0%) ATTRm patients, there was a trend towards a reduction in all-cause mortality in the T/T group (33/63; 52.4%) compared with the P/T group (29/43; 67.4%); 0.66 (0.39, 1.09); P=0.17. In patients who were NYHA Class I or II at baseline, all-cause mortality was significantly reduced in the T/T group (38/186; 20.4%) compared with the P/T group (45/114; 39.5%); 0.49 (0.32, 0.75); P=0.001. In those patients with more severe symptoms at baseline (NYHA Class III), there were fewer deaths in the T/T group (50/78; 64.1%) compared with the P/T group (44/63; 69.8%); 0.80 (0.53, 1.21), but this difference was not statistically significant (P=0.50).

Conclusions

In ATTR-ACT, tafamidis was shown to significantly improve survival, functional capacity, and quality of life in patients with ATTR-CM. This pooled analysis with data from the ongoing extension study further supports the efficacy of tafamidis in patients over a longer period of time and the importance of early diagnosis and treatment.

Acknowledgement/Funding

This study was sponsored by Pfizer.

Acoustic buffeting by infrasound in a low vibration facility

Measurement instruments and fabrication tools with spatial resolution on the atomic scale require facilities that mitigate the impact of vibration sources in the environment. One approach to protection from vibration in a building's foundation is to place the instrument on a massive inertia block, supported on pneumatic isolators. This opens the questions of whether or not a massive floating block is susceptible to acoustic forces, and how to mitigate the effects of any such acoustic buffeting. Here this is investigated with quantitative measurements of vibrations and sound pressure, together with finite element modeling. It is shown that a particular concern, even in a facility with multiple acoustic enclosures, is the excitation of the lowest fundamental acoustic modes of the room by infrasound in the low tens of Hz range, and the efficient coupling of the fundamental room modes to a large inertia block centered in the room.

Intermodal energy transfer in a tapered optical fiber: optimizing transmission

We present an experimental and theoretical study of the energy transfer between modes during the tapering process of an optical nanofiber through spectrogram analysis. The results allow optimization of the tapering process, and we measure transmission in excess of 99.95% for the fundamental mode. We quantify the adiabaticity condition through calculations and place an upper bound on the amount of energy transferred to other modes at each step of the tapering, giving practical limits to the tapering angle.

A low-loss photonic silica nanofiber for higher-order modes

Optical nanofibers confine light to subwavelength scales, and are of interest for the design, integration, and interconnection of nanophotonic devices. Here we demonstrate high transmission (> 97%) of the first family of excited modes through a 350 nm radius fiber, by appropriate choice of the fiber and precise control of the taper geometry. We can design the nanofibers so that these modes propagate with most of their energy outside the waist region. We also present an optical setup for selectively launching these modes with less than 1% fundamental mode contamination. Our experimental results are in good agreement with simulations of the propagation. Multimode optical nanofibers expand the photonic toolbox, and may aid in the realization of a fully integrated nanoscale device for communication science, laser science or other sensing applications.

Scanning tunneling spectroscopy and vortex imaging in the iron pnictide superconductor BaFe1.8Co0.2As2

We present an atomic resolution scanning tunneling spectroscopy study of superconducting BaFe1.8Co0.2As2 single crystals in magnetic fields up to 9 T. At zero field, a single gap with coherence peaks at Delta=6.25 meV is observed in the density of states. At 9 and 6 T, we image a disordered vortex lattice, consistent with isotropic, single flux quantum vortices. Vortex locations are uncorrelated with strong-scattering surface impurities, demonstrating bulk pinning. The vortex-induced subgap density of states fits an exponential decay from the vortex center, from which we extract a coherence length xi=27.6+/-2.9 A, corresponding to an upper critical field Hc2=43 T.

Coincidence of checkerboard charge order and antinodal state decoherence in strongly underdoped superconducting Bi2Sr2CaCu2O8 + delta)

The doping dependence of nanoscale electronic structure in superconducting Bi(2)Sr(2)CaCu(2)O(8 + delta) is studied by scanning tunneling microscopy. At all dopings, the low energy density-of-states modulations are analyzed according to a simple model of quasiparticle interference and found to be consistent with Fermi-arc superconductivity. The superconducting coherence peaks, ubiquitous in near-optimal tunneling spectra, are destroyed with strong underdoping and a new spectral type appears. Exclusively in regions exhibiting this new spectrum, we find local "checkerboard" charge ordering of high energy states, with a wave vector of Q = (+/- 2pi/4.5a(0),0); (0, +/- 2pi/4.5a(0)) +/- 15%. Surprisingly, this spatial ordering of high energy states coexists harmoniously with the low energy Bogoliubov quasiparticle states.

Relating atomic-scale electronic phenomena to wave-like quasiparticle states in superconducting Bi2Sr2CaCu2O8+delta

The electronic structure of simple crystalline solids can be completely described in terms either of local quantum states in real space (r-space), or of wave-like states defined in momentum-space (k-space). However, in the copper oxide superconductors, neither of these descriptions alone may be sufficient. Indeed, comparisons between r-space and k-space studies of Bi2Sr2CaCu2O8+delta (Bi-2212) reveal numerous unexplained phenomena and apparent contradictions. Here, to explore these issues, we report Fourier transform studies of atomic-scale spatial modulations in the Bi-2212 density of states. When analysed as arising from quasiparticle interference, the modulations yield elements of the Fermi-surface and energy gap in agreement with photoemission experiments. The consistency of numerous sets of dispersing modulations with the quasiparticle interference model shows that no additional order parameter is required. We also explore the momentum-space structure of the unoccupied states that are inaccessible to photoemission, and find strong similarities to the structure of the occupied states. The copper oxide quasiparticles therefore apparently exhibit particle-hole mixing similar to that of conventional superconductors. Near the energy gap maximum, the modulations become intense, commensurate with the crystal, and bounded by nanometre-scale domains. Scattering of the antinodal quasiparticles is therefore strongly influenced by nanometre-scale disorder.

Imaging quasiparticle interference in Bi2Sr2CaCu2O8+delta

Scanning tunneling spectroscopy of the high-Tc superconductor Bi2Sr2CaCu2O8+delta reveals weak, incommensurate, spatial modulations in the tunneling conductance. Images of these energy-dependent modulations are Fourier analyzed to yield the dispersion of their wavevectors. Comparison of the dispersions with photoemission spectroscopy data indicates that quasiparticle interference, due to elastic scattering between characteristic regions of momentum-space, provides a consistent explanation for the conductance modulations, without appeal to another order parameter. These results refocus attention on quasiparticle scattering processes as potential explanations for other incommensurate phenomena in the cuprates. The momentum-resolved tunneling spectroscopy demonstrated here also provides a new technique with which to study quasiparticles in correlated materials.

Imaging the granular structure of high-Tc superconductivity in underdoped Bi2Sr2CaCu2O8+delta

Granular superconductivity occurs when microscopic superconducting grains are separated by non-superconducting regions; Josephson tunnelling between the grains establishes the macroscopic superconducting state. Although crystals of the copper oxide high-transition-temperature (high-Tc) superconductors are not granular in a structural sense, theory suggests that at low levels of hole doping the holes can become concentrated at certain locations resulting in hole-rich superconducting domains. Granular superconductivity arising from tunnelling between such domains would represent a new view of the underdoped copper oxide superconductors. Here we report scanning tunnelling microscope studies of underdoped Bi2Sr2CaCu2O8+delta that reveal an apparent segregation of the electronic structure into superconducting domains that are approximately 3 nm in size (and local energy gap <50 meV), located in an electronically distinct background. We used scattering resonances at Ni impurity atoms as 'markers' for local superconductivity; no Ni resonances were detected in any region where the local energy gap Delta > 50 +/- 2.5 meV. These observations suggest that underdoped Bi2Sr2CaCu2O8+delta is a mixture of two different short-range electronic orders with the long-range characteristics of a granular superconductor.

A four unit cell periodic pattern of quasi-particle states surrounding vortex cores in Bi2Sr2CaCu2O8+delta

Scanning tunneling microscopy is used to image the additional quasi-particle states generated by quantized vortices in the high critical temperature superconductor Bi2Sr2CaCu2O8+delta. They exhibit a copper-oxygen bond-oriented "checkerboard" pattern, with four unit cell (4a0) periodicity and a approximately 30 angstrom decay length. These electronic modulations may be related to the magnetic field-induced, 8a0 periodic, spin density modulations with decay length of approximately 70 angstroms recently discovered in La1.84Sr0.16CuO4. The proposed explanation is a spin density wave localized surrounding each vortex core. General theoretical principles predict that, in the cuprates, a localized spin modulation of wavelength lambda should be associated with a corresponding electronic modulation of wavelength lambda/2, in good agreement with our observations.

Chondrocyte death precedes structural damage in blunt impact trauma

Joint impact trauma has been shown to cause fissures, fibrillation, and other structural damage of the cartilage or subchondral bone. Previous studies used impact energies sufficient to fracture the underlying bone. Under these circumstances, the initial influence of impact trauma on cellular components and cartilage structure is unknown. The goal of this study was to determine whether an impact trauma first causes cellular or structural damage to a cartilage layer. Such damage might be the starting point of degenerative changes found in osteoarthrosis. Porcine patellas (n = 12) were subjected to standardized low-impact loading of three magnitudes with a spherical impactor attached to a drop tower device (0.06, 0.1, and 0.2 J). India ink staining and scanning electron microscopic analysis were used for analysis and showed no evidence of gross structural disruption. Chondrocyte viability assessed with thiazole blue staining and propidium iodide counterstaining was reduced significantly in the tangential and middle zones with increasing impact energy. These results indicate that chondrocyte death may precede excessive structural damage reported in earlier studies and might be a crucial factor in posttraumatic osteoarthrosis.

The role of visual attention in saccadic eye movements

The relationship between saccadic eye movements and covert orienting or visual spatial attention was investigated in two experiments. In the first experiment, subjects were required to make a saccade to a specified location while also detecting a visual target presented just prior to the eye movement. Detection accuracy was highest when the location of the target coincided with the location of the saccade, suggesting that subjects use spatial attention in the programming and/or execution of saccadic eye movements. In the second experiment, subjects were explicitly directed to attend to a particular location and to make a saccade to the same location or to a different one. Superior target detection occurred at the saccade location regardless of attention instructions. This finding shows that subjects cannot move their eyes to one location and attend to a different one. The result of these experiments suggest that visuospatial attention is an important mechanism in generating voluntary saccadic eye movements.

Recognition memory and attentional selection: serial scanning is not enough

In two experiments, using memory sets of up to 10 letters, the response competition paradigm was employed to investigate the extent to which extraneous visual stimuli interfere with or affect the process of memory search. It was assumed that if selective attention could exclude the effect of noise letters from a Sternberg-type memory comparison process, then there would be an increase in intercept for the reaction time-set size functions but no increase in slope. This result was obtained. However, a large difference in response times to both positive and negative set targets was found when the accompanying noise letters indicated a competing response, as opposed to when they indicated the same response as the target. This implies rapid identification of the nature of both target and noise, independent of a serial comparison process. A modification of a dual process model (Juola, Fischler, Wood, & Atkinson, 1971) in which stimuli activate a familiarity value independent of memory search was suggested to account for these results.

Hyperpyrexia associated with intravenous cimetidine therapy. Report of a case

Fever as a drug reaction is common. It has, however, not been widely recognized as a complication of cimetidine therapy. We observed a patient who, during the administration of intravenous cimetidine, became hyperpyretic and confused. Six hours after cimetidine therapy was discontinued, he became afebrile. The potential for hyperpyrexia to occur with cimetidine should be considered in patients with unexplained fever who are receiving this drug.

Conjunction of color and form without attention: evidence from an orientation-contingent color aftereffect

According to feature-integration theory (Treisman & Gelade, 1980), separable features such as color and shape exist in separate maps in preattentive vision and can be integrated only through the use of spatial attention. Many perceptual aftereffects, however, which are also assumed to reflect the features available in preattentive vision, are sensitive to conjunctions of features. One possible resolution of these views holds that adaptation to conjunctions depends on spatial attention. We tested this proposition by presenting observers with gratings varying in color and orientation. The resulting McCollough aftereffects were independent of whether the adaptation stimuli were presented inside or outside of the focus of spatial attention. Therefore, color and shape appear to be conjoined preattentively, when perceptual aftereffects are used as the measure. These same stimuli, however, appeared to be separable in two additional experiments that required observers to search for gratings of a specified color and orientation. These results show that different experimental procedures may be tapping into different stages of preattentive vision.

Recognition memory and attentional selection: Serial scanning is not enough

In two experiments, using memory sets of up to 10 letters, the response competition paradigm was employed to investigate the extent to which extraneous visual stimuli interfere with or affect the process of memory search. It was assumed that if selective attention could exclude the effect of noise letters from a Sternberg-type memory comparison process, then there would be an increase in intercept for the reaction time-set size functions but no increase in slope. This result was obtained. However, a large difference in response times to both positive and negative set targets was found when the accompanying noise letters indicated a competing response, as opposed to when they indicated the same response as the target. This implies rapid identification of the nature of both target and noise, independent of a serial comparison process. A modification of a dual process model (Juola, Fischler, Wood, & Atkinson, 1971) in which stimuli activate a familiarity value independent of memory search was suggested to account for these results.

Conjunction of color and form without attention: Evidence from an orientation-contingent color aftereffect

According to feature-integration theory (Treisman & Gelade, 1980), separable features such as color and shape exist in separate maps in preattentive vision and can be integrated only through the use of spatial attention. Many perceptual aftereffects, however, which are also assumed to reflect the features available in preattentive vision, are sensitive to conjunctions of features. One possible resolution of these views holds that adaptation to conjunctions depends on spatial attention. We tested this proposition by presenting observers with gratings varying in color and orientation. The resulting McCollough aftereffects were independent of whether the adaptation stimuli were presented inside or outside of the focus of spatial attention. Therefore, color and shape appear to be conjoined preattentively, when perceptual aftereffects are used as the measure. These same stimuli, however, appeared to be separable in two additional experiments that required observers to search for gratings of a specified color and orientation. These results show that different experimental procedures may be tapping into different stages of preattentive vision.

Event-related potentials elicited by automatic targets: a dual-task analysis

The role of limited capacity processes in the detection of automatic targets was investigated in a dual-task paradigm using both behavioral and event-related brain potential (ERP) measures. An automatic detection task was paired with another concurrent discrimination while the relative importance of each task was systematically varied. The resulting performance operating characteristic (POC) showed that both the speed and accuracy of automatic detection responses were affected by the allocation of attention. Reductions in the accuracy of each task were accompanied by reductions in the amplitude of a late-positive component of the ERP (P300). In addition, the latency of the P300 component elicited by automatic targets was increased in dual-task conditions. A comparison of behavioral and ERP measures suggested the involvement of two separate limited-capacity processes in automatic detection: one concerned with the formation of an episodic representation of target occurrence and the other with the execution of rapid motor responses.

Event-related potentials elicited by automatic targets: A dual-task analysis

The role of limited capacity processes in the detection of automatic targets was investigated in a dual-task paradigm using both behavioral and event-related brain potential (ERP) measures. An automatic detection task was paired with another concurrent discrimination while the relative importance of each task was systematically varied. The resulting performance operating characteristic (POC) showed that both the speed and accuracy of automatic detection responses were affected by the allocation of attention. Reductions in the accuracy of each task were accompanied by reductions in the amplitude of a late-positive component of the ERP (P300). In addition, the latency of the P300 component elicited by automatic targets was increased in dual-task conditions. A comparison of behavioral and ERP measures suggested the involvement of two separate limited-capacity processes in automatic detection: one concerned with the formation of an episodic representation of target occurrence and the other with the execution of rapid motor responses.

The component structure of event-related slow potentials: task, ISI, and warning stimulus effects on the 'E' wave

Two experiments were conducted to investigate the role of task variables and ISI length on the late component of the event-related slow potential (ERSP) recorded during various two-stimulus anticipation tasks. In the first experiment, a two-component ERSP was observed during short (1 sec) and long (4 sec) ISI conditions. The first component was generally Fz dominant and independent of task variables. The second component was generally Cz dominant and most prominent when an immediate motor response was required. A second experiment was successful in eliciting large second ERSP components even in the absence of response requirements. In this experiment, the topography of the second component was not exclusively Cz dominant; rather, it was task dependent, and achieved Fz dominance under delayed-response conditions. Heart rate, monitored concurrently with the EEG, also reflected the change in experimental conditions by the enhancement of a mid-ISI acceleratory component. The data are discussed with respect to a multiple-component model of slow potential activity during periods in which subjects anticipate significant events.

Interaction between global and local levels of a form

Two experiments investigated a model for global procedence, which states that global aspects of a form are invariably recognized prior to local levels. Experiment 1 showed that speed of recognition was approximately the same for global and local levels of a form. Experiment 2 independently manipulated the "quality" of information at global and local levels by distorting the forms. Either local or global precedence could be obtained depending on which level was distorted. These results suggest that the specific interaction between local and global levels will depend on the relative visibility or quality of form information at each level.

Lack of glucagon response to hypoglycemia in diabetic autonomic neuropathy

Glucagon response to insulin hypoglycemia was tested in diabetics with autonomic neuropathy (N=9), diabetics without neuropathy (N=8), and normals (N=9). With similar levels of hypoglycemia, growth hormone and plasma cortisol increased in all groups. The glucagon response in normals (121+/-19 vs. 308+/-30 pg./ml., mean+/-S.E.M. of baseline vs. hypoglycemia peak) was significantly less in nonneuropathic diabetics than in normals (128+/-13 vs. 209+/-30) and absent in neuropathic diabetes (128+/-23 vs. 115+/-20). Arginine stimulation produced a glucagon response in the neuropathic diabetics (106+/-16 vs. 523+/-103). The data indicate that the capacity to release glucagon during hypoglycemia is lost in diabetic neuropathy while glucagon responsiveness to arginine is retained. Neuropathy in diabetes may contribute to metabolic instability.

Multiple gastric polyps and parathyroid adenomas. Report of two cases

Two cases of multiple gastric polyps associated with parathyroid adenomas are presented. A review of the literature revealed four patients with multiple gastric polyps and multiple endocrine adenomatosis. The possiblity of multiple gastric polyps as a variant of the MEA syndrome complex is explored. Emphasis is placed on the need for thorough endocrine evaluation in patients with multiple gastric polyps.

Real-time fourier spectroscopy

The operation and performance of a system to perform Fourier spectroscopy in real time is described. The interferogram is sampled and the spectrum is simultaneously synthesized by the summation of a series of cosine functions with amplitudes and frequencies determined by the sample points. A digital memory oscilloscope performs the summation, and the spectral distribution is presented at 1000 points. An error of 2% of the full scale output can be expected and is caused by several inaccuracies in the components of the system. Several ir spectra were investigated, and the results produced by the real-time system are compared with those obtained with a digital and a special purpose analog computer.

Real-time spectral synthesis in Fourier spectroscopy

A real-time technique to synthesize the spectral distribution from the corresponding interferogram is described. A portable real-time synthesizer has been constructed and test results are presented. Functions with known spectra and an actual interferogram have been used for purposes of evaluation.