Characterizing the graded structure of false killer whale (Pseudorca crassidens) vocalizations

The vocalizations from two, captive false killer whales (Pseudorca crassidens) were analyzed. The structure of the vocalizations was best modeled as lying along a continuum with trains of discrete, exponentially damped sinusoidal pulses at one end and continuous sinusoidal signals at the other end. Pulse trains were graded as a function of the interval between pulses where the minimum interval between pulses could be zero milliseconds. The transition from a pulse train with no inter-pulse interval to a whistle could be modeled by gradations in the degree of damping. There were many examples of vocalizations that were gradually modulated from pulse trains to whistles. There were also vocalizations that showed rapid shifts in signal type--for example, switching immediately from a whistle to a pulse train. These data have implications when considering both the possible function(s) of the vocalizations and the potential sound production mechanism(s). A short-time duty cycle measure was developed to characterize the graded structure of the vocalizations. A random sample of 500 vocalizations was characterized by combining the duty cycle measure with peak frequency measurements. The analysis method proved to be an effective metric for describing the graded structure of false killer whale vocalizations.

Generalization of 'same-different' classification abilities in bottlenosed dolphins

Two bottlenosed dolphins taught to classify pairs of three-dimensional objects as either same or different were tested with novel stimulus sets to determine how well their classification abilities would generalize. Both dolphins were immediately able to classify novel pairs of planar objects, differing only in shape, as same or different. When tested on sets of three objects consisting of either all different objects or of two identical objects and one different object, both dolphins proved to be able to classify 'all different' sets as different and 'not all different' sets as same, at levels significantly above chance. These data suggest that dolphins can use knowledge about similarity-based classification strategies gained from previous training to perform successfully in a variety of novel same-different classification tasks. Visual classificatory abilities of dolphins appear to be comparable to those that have been demonstrated in primates.

Basal forebrain stimulation changes cortical sensitivities to complex sound

Experience affects how brains respond to sound. Here, we examined how the sensitivity and selectivity of auditory cortical neuronal responses were affected in adult rats by the repeated presentation of a complex sound that was paired with basal forebrain stimulation. The auditory cortical region that was responsive to complex sound was 2-5 five times greater in area in paired-stimulation rats than in naive rats. Magnitudes of neuronal responses evoked by complex sounds were also greatly increased by associative pairing, as were the percentages of neurons that responded selectively to the specific spectrotemporal features that were paired with stimulation. These findings demonstrate that feature selectivity within the auditory cortex can be flexibly altered in adult mammals through appropriate intensive training.

Participation of membrane sulfhydryl groups in the epididymal maturation of human and rabbit spermatozoa

Changes in the concentration of -SH groups on the human and rabbit spermatozoal membrane and during epididymal maturation were studied by means of a new fluorescent probe, carboxyphenylmaleimide (CPhM), which reacts specifically with -SH groups. Binding of CPhM did not modify oxygen uptake, motility, or viability of the sperm cells used, but produced a characteristic increase in fluorescence. By analysis of this increase it was possible to calculate the presence of 35 +/- 4.2 and 55 +/- 8 nmoles of exposed -SH groups/10(8) rabbit and human ejaculated spermatozoa, respectively. Caput epididymal cells bound significantly more CPhM than did cauda epididymal cells or ejaculated spermatozoa (155 +/- 22, 78 +/- 11, and 35 +/- 4.2 nmoles/10(8) cells, respectively, in rabbit cells; and 184, 110 +/- 18, and 55 +/- 8 nmoles/10(8) cells, respectively, in humans cells). In addition to the differences in number of exposed -SH groups observed between human and rabbit sperm cells, the behavior of these membrane-reactive groups when ethylenediaminetetraacetate and/or zinc were added to the incubation media indicates that the participation of membrane--SH groups in sperm physiology is species-specific.

Environmental constraints on sound transmission by humpback whales

Singing humpback whales in Hawaii produce a variety of sounds at high source levels (ca. 185 dB re: 1 microPa), in coastal waters 15-500 m deep. These sounds are attenuated and distorted as they propagate away from a singer, limiting the utilizable range of the sounds. In the current study, simulations based on normal-mode theory were used to investigate how the effects of shallow-water propagation constrain humpback whales' use of sound. It is shown that humpbacks can greatly affect transmission range by adjusting their positions and sounds in response to environmental factors. Source depth, in particular, is shown to be a major determinant of which frequencies propagate the farthest. A preliminary analysis of range-dependent distortion suggests that spectral cues can potentially provide listening whales with information about how far a sound has traveled.

Spectrotemporal sensitivities in rat auditory cortical neurons

Studies in several mammalian species have demonstrated that auditory cortical neurons respond strongly to single frequency-modulated (FM) sweeps, and that most responses are selective for sweep direction and/or rate. In the present study, we used extracellular recordings to examine how neurons in the auditory cortices of anesthetized rats respond to continuous, periodic trains of FM sweeps (described previously by deCharms et al., Science 280 (1998) pp. 1439-1444, as moving auditory gratings). Consistent with previous observations in owl monkeys, we found that the majority of cortical neurons responded selectively to trains of either up-sweeps or down-sweeps; selectivity for down-sweeps was most common. Periodic responses were typically evoked only by sweep trains with repetition rates less than 12 sweeps per second. Directional differences in responses were dependent on repetition rate. Our results support the proposal that a combination of both spectral and temporal acoustic features determines the responses of auditory cortical neurons to sound, and add to the growing body of evidence indicating that the traditional view of the auditory cortex as a frequency analyzer is not sufficient to explain how the mammalian brain represents complex sounds.

The neural network classification of false killer whale (Pseudorca crassidens) vocalizations

This study reports the use of unsupervised, self-organizing neural network to categorize the repertoire of false killer whale vocalizations. Self-organizing networks are capable of detecting patterns in their input and partitioning those patterns into categories without requiring that the number or types of categories be predefined. The inputs for the neural networks were two-dimensional characterization of false killer whale vocalization, where each vocalization was characterized by a sequence of short-time measurements of duty cycle and peak frequency. The first neural network used competitive learning, where units in a competitive layer distributed themselves to recognize frequently presented input vectors. This network resulted in classes representing typical patterns in the vocalizations. The second network was a Kohonen feature map which organized the outputs topologically, providing a graphical organization of pattern relationships. The networks performed well as measured by (1) the average correlation between the input vectors and the weight vectors for each category, and (2) the ability of the networks to classify novel vocalizations. The techniques used in this study could easily be applied to other species and facilitate the development of objective, comprehensive repertoire models.

Eight-plate epiphysiodesis

Aims

Guided growth using eight-plates is commonly used for correction of angular limb deformities in growing children. The principle is of tethering at the physeal periphery while enabling growth in the rest of the physis. The method is also applied for epiphysiodesis to correct limb-length discrepancy (LLD). Concerns have been raised regarding the potential of this method to create an epiphyseal deformity. However, this has not been investigated. The purpose of this study was to detect and quantify the occurrence of deformities in the proximal tibial epiphysis following treatment with eight-plates.

Patients and Methods

A retrospective study was performed including 42 children at a mean age of 10.8 years (3.7 to 15.7) undergoing eight-plate insertion in the proximal tibia for correction of coronal plane deformities or LLD between 2007 and 2015. A total of 64 plates were inserted; 48 plates (34 patients) were inserted to correct angular deformities and 16 plates (8 patients) for LLD. Medical records, Picture Archive and Communication System images, and conventional radiographs were reviewed. Measurements included interscrew angle, lateral and medial plateau slope angles measured between the plateau surface and the line between the ends of the physis, and tibial plateau roof angle defined as 180° minus the sum of both plateau angles. Measurements were compared between radiographs performed adjacent to surgery and those at latest follow-up, and between operated and non-operated plateaus. Statistical analysis was performed using BMDP Statistical Software.

Results

Slope angle increased in 31 (49.2%) of operated epiphyses by a mean of 5° (1° to 23°) compared with 29 (31.9%) in non-operated epiphyses (p = 0.043). Roof angle decreased in 29 (46.0%) of operated tibias and in 25 (27.5%) of non-operated ones by a mean of 5° (1° to 18°) (p = 0.028). Slope angle change frequency was similar in patients with LLD, varus and valgus correction (p = 0.37) but roof angle changes were slightly more frequent in LLD (p = 0.059) and correlated with the change in inter screw angles (r = 0.74, p = 0.001).

Conclusion

The use of eight-plates in the proximal tibia for deformity correction and limb-length equalization causes a change in the bony morphology of the tibial plateau in a significant number of patients and the effect is more pronounced in the correction of LLD. Cite this article: Bone Joint J 2018;100-B:1112–16.

A computational model of mechanisms controlling experience-dependent reorganization of representational maps in auditory cortex

Cortical representations of sound can be modified by repeatedly pairing presentation of a pure tone with electrical stimulation of neuromodulatory neurons located in the basal forebrain (Bakin & Weinberger, 1996; Kilgard & Merzenich, 1998a). We developed a computational model to investigate the possible effects of basal forebrain modulation on map reorganization in the auditory cortex. The model is a self-organizing map with acoustic response characteristics mimicking those observed in the mammalian auditory cortex. We simulated the effects of basal forebrain modulation, using parameters intrinsic to the self-organizing map, such as the learning rate (controlling the adaptability of map nodes) and the neighborhood function (controlling the excitability of map nodes). Previous research has suggested that both parameters can be useful for characterizing the effects of neuromodulation on plasticity (Kohonen, 1993; Myers et al., 1996; Myers, Ermita, Hasselmo, & Gluck, 1998). The model successfully accounts for experimentally observed effects of pairing basal forebrain stimulation with the presentation of a single tone, but not of two tones, suggesting that auditory cortical plasticity is constrained in ways not accounted for by current theories. Despite this limitation, the model provides a useful framework for describing experience-induced changes in auditory representations and for relating such changes to variations in the excitability and adaptability of cortical neurons produced by neuromodulation.

HUMAN PAPILLOMAVIRUS HPV-16 DNA AS AN EPITHELIOTROPIC VIRUS THAT INDUCES HYPERPROLIFERATION IN SQUAMOUS PENILE TISSUE

The prevalence of human papillomavirus HPV-16DNA sequences in 57 penile carcinoma biopsies was examined using the polymerase chain reaction (PCR) with type specific internal probes, employing HPV consensus primers from the L1 region. The cases comprised 39 typical squamous cell carcinoma and 18 specimens with different subtype. PCR products were analyzed and HPV-16DNA was detected in a high percentage of specimens. Thirty-eight biopsies were HPV-16DNA positive. This determination was correlated with cellular differentiation and growth pattern. Our data corroborates that squamous cell carcinoma was invariably associated with HPV-16DNA.

Understanding auditory distance estimation by humpback whales: a computational approach

Ranging, the ability to judge the distance to a sound source, depends on the presence of predictable patterns of attenuation. We measured long-range sound propagation in coastal waters to assess whether humpback whales might use frequency degradation cues to range singing whales. Two types of neural networks, a multi-layer and a single-layer perceptron, were trained to classify recorded sounds by distance traveled based on their frequency content. The multi-layer network successfully classified received sounds, demonstrating that the distorting effects of underwater propagation on frequency content provide sufficient cues to estimate source distance. Normalizing received sounds with respect to ambient noise levels increased the accuracy of distance estimates by single-layer perceptrons, indicating that familiarity with background noise can potentially improve a listening whale's ability to range. To assess whether frequency patterns predictive of source distance were likely to be perceived by whales, recordings were pre-processed using a computational model of the humpback whale's peripheral auditory system. Although signals processed with this model contained less information than the original recordings, neural networks trained with these physiologically based representations estimated source distance more accurately, suggesting that listening whales should be able to range singers using distance-dependent changes in frequency content.

Ca2+/calmodulin system: participation in the progesterone-induced facilitation of lordosis behavior in the ovariectomized estrogen-primed rat

We studied the effect some drugs that participate in the Ca2+/ calmodulin system have on the progesterone (P) facilitation of lordosis behavior in ovariectomized estradiol (E2) primed rats. We injected rats 44 h after E2 priming with 2 mg P together with various dosages of one of the following compounds: pentobarbital, trifluoperazine (TPZ), promethazine (PMZ), Chlorpromazine (CPZ), haloperidol (HAL), pimozide (PIM), and verapamil (VER). Then 4 h after treatment, animals were tested for sexual behavior, expressed as the lordosis quotient (LQ). All drugs at 4 mg/kg or higher inhibited lordosis, but only HAL, PIM, and VER were active at 1 mg/kg. The maximum level of activity was shown by PIM, although at the dose of 8 mg/kg no statistical differences were found between this compound and TPZ or HAL. Pentobarbital (25 mg/kg) showed no significant difference from saline-treated controls. The activity of the tested drugs on the facilitation of sexual behavior appears to be related to their efficiency as inhibitors of calmodulin (CaM)-dependent phosphodiesterase and as ligands for the Ca(2+)-CaM complex.

Passivation of Layered Gallium Telluride by Double Encapsulation with Graphene

Layered semiconductor gallium telluride (GaTe) undergoes a rapid structural transition to a degraded phase in ambient conditions, limiting its utility in devices such as optical switches. In this work, we demonstrate that the degradation process in GaTe flakes can be slowed down dramatically via encapsulation with graphene. Through examining Raman signatures of degradation, we show that the choice of substrate significantly impacts the degradation rate and that the process is accelerated by the transfer of GaTe to hydrophilic substrates such as SiO₂/Si. We find that double encapsulation with both top and bottom graphene layers can extend the lifetime of the material for several weeks. The photoresponse of flakes encapsulated in this way is only reduced by 17.6 ± 0.4% after 2 weeks, whereas unencapsulated flakes display no response after this time. Our results demonstrate the potential for alternative, van der Waals material-based passivation strategies in unstable layered materials and highlight the need for careful selection of substrates for 2D electronic devices.

Microsomal and plasma membrane sialyltransferase activity in rat epididymis

3H-sialyl residues transfer by subcellular epididymal fractions [plasma membrane (PM), microsomes (MI), and mitochondria (MT)] to both endogenous and exogenous acceptors was studied. Their fraction purity was valued (5' nucleotidase and glucose 6-phosphatase activities). The glycoprotein or glycolipid N-acetyl neuraminyl transferase activity in microsomes were 5 times higher in caput than in cauda (624 to 125 pmoles/30 min/mg protein). PM activity also was higher in caput. In MT fraction, the activity was smaller. Two mechanisms related to spermatozoa glycoprotein changes during maturation are proposed: secretion to the lumen of molecules previously glycosilated in microsomes and transialylation to spermatozoa from membranal ectoenzymes localized on the surface of the epididymal epithelium.

Participation of DNA structure on sperm chromatin organization

The in vitro interaction between purified bovine liver and sperm DNA with somatic histones, to form nucleosomes, and with bovine and salmon protamines were studied. DNAse or microccocal nuclease digestion of liver DNA-histone reassociated chromatin produced the expected polynucleosome type of fragments. Electrophoretic patterns of digested sperm-DNA nucleosomes were different. Micrococcal nuclease digestion produced mainly fragments smaller than 100 bp and some nucleosome-type particles. Under DNAse activity most of the products were smaller than 100 bp, indicating an increased susceptibility of the sperm DNA-histone complexes to the hydrolytic activity of both nucleases, particularly toward DNAse I. This differential susceptibility was confirmed by sucrose gradient spectrophotometric analysis. Acridine orange (AO) staining of histone-DNA reassociated nucleosomes showed significant differences in fluorescence intensity, sperm DNA-histone complexes being almost twice as fluorescent as liver DNA-histone complexes. On the contrary, liver DNA/protamine complexes stained with AO were consistently more fluorescent than sperm DNA-protamine complexes. Finally, no differences in either fluorescence intensity or spectra were observed when liver and sperm DNA were stained with AO after interaction with salmon protamines. The data suggest that sperm DNA has important structural characteristics that differentiates it from somatic DNA. These differences seem to be species specific and must surely play an important role on the determination of the dramatic sequence of that participates sperm chromatin organization.

PROSTATIC CANCER/BENIGN PROSTATIC HYPERTROPHY. SUBCELLULAR DISTRIBUTION OF ESTRADIOL/ANDROGEN RECEPTORS

Six microsomal population of estradiol and androgen receptors have been characterized in human benign prostatic hypertrophy (BPH) and prostate cancer (PCa). Estradiol receptor (ER) and androgen receptors (AR) were extracted using 0.6 M KCL and determined by the dextran-coated charcoal method. ER and AR levels were smaller in BPH plasma membranes (PM) than in Pca cases. For functions 3, 4, 6, the ER values in PCa were 25-38% less with regard to BPH ER values. Whereas in PCa, AR values obtained in all fractions were higher when compared to BPH AR values. In benign prostatic hypertrophy and prostatic cancer, ER and AR levels were significantly higher in the nuclear fraction. In the nuclear fraction, ER and AR levels in BPH and PCa were significantly different. The subcellular distribution of AR and ER in BPH and PCa constitutes a reservation mechanism and processing a receptors for their continued growth.

Impact of Polymer Residue Level on the In-Plane Thermal Conductivity of Suspended Large-Area Graphene Sheets

The presence of polymer transfer residues on graphene surfaces is a major bottleneck to overcome for the commercial and industrial viability of devices incorporating graphene layers. In particular, how clean the surface must be to recover high (>2500 W/mK) thermal conductivity and maximize the heat spreading capability of graphene for thermal management applications remains unclear. Here, we present the first systematic study of the impact of different levels of polymer residues on the in-plane thermal conductivity (κ_r) of single-layer graphene (SLG) fabricated by chemical vapor deposition (CVD). Control over the quantity of surface residue was achieved by varying the length of time each sample was rinsed in toluene to remove the poly(methyl methacrylate) (PMMA) support layer. The level of residue contamination was assessed using atomic force microscopy (AFM) and optical characterization. The thermal conductivity of the suspended SLG was measured using an optothermal Raman technique. We observed that the presence of polymer surface residue has a significant impact on the thermal properties of SLG, with the most heavily contaminated sample exhibiting a κ_r as low as (905 +155/-100) W/mK. Even without complete eradication of surface residues, a thermal conductivity as high as (3100 +1400/-900) W/mK was recovered, where the separation between adjacent clusters was sufficiently large (>700 nm). The proportion of the SLG surface covered by residues and the mean separation distance between clusters were found to be key factors in determining the level of κ_r suppression. This work has important implications for future large-scale graphene fabrication and transfer, particularly where graphene is to be used as a heat spreading layer in devices. The possibility of new opportunities for manipulation of the thermal properties of SLG via PMMA nanopatterning is also raised.

Effect of cupric ions on the initiation protein synthesis rate in the human endometrium

The effect of cupric ions on the initiation protein synthesis rate of the human endometrium was studied. Addition of copper to the complete ribosomal system decreased the binding of [3H]Met-tRNA(i) to the isolated ribosomes with a plateau at about 70% inhibition with concentrations higher than 150 microM. The initiation activity was GTP-dependent with a maximum at 2 mM. This activity was very rapid, requiring 5 min to complete the reaction. Incubation of isolated initiation factors with copper (300 microM) inhibited the formation of the ternary complex. When the complete system was reconstituted with salt-washed ribosomes after ternary complex formation, no significant change on the inhibition pattern was observed. Addition of initiation factors to 5-min preincubated salt-washed ribosomes with 300 microM copper, after the elimination of excess copper, induced only a 12% decrease on Met-tRNA(i) binding. This effect was not modified by the presence of Sparsomycin, an elongation inhibitor. It was concluded that copper interferes with the initiation process, probably at the ternary complex formation level.