Explore the vast range of titles available.

Optical wave packets that are localized in space and time, but nevertheless overcome diffraction and travel rigidly in free space, are a long sought-after field structure with applications ranging from microscopy and remote sensing, to nonlinear and quantum optics. However, synthesizing such wave packets requires introducing non-differentiable angular dispersion with high spectral precision in two transverse dimensions, a capability that has eluded optics to date. Here, we describe an experimental strategy capable of sculpting the spatio-temporal spectrum of a generic pulsed beam by introducing arbitrary radial chirp via two-dimensional conformal coordinate transformations of the spectrally resolved field. This procedure yields propagation-invariant ‘space-time’ wave packets localized in all dimensions, with tunable group velocity in the range from 0.7 c to 1.8 c in free space, and endowed with prescribed orbital angular momentum. By providing unprecedented flexibility in sculpting the three-dimensional structure of pulsed optical fields, our experimental strategy promises to be a versatile platform for the emerging enterprise of space-time optics. Propagation-invariant wave packets confined in space and time can be useful for optical sensing, imaging, and nonlinear and quantum optics. Here the authors demonstrate control over the angular dispersion of optical wave packets in two-transverse dimensions to synthesize space-time wave packets localized in all dimensions.

Skyrmions, topologically non-trivial localized spin structures, are fertile ground for exploring emergent phenomena in condensed matter physics and next-generation magnetic-memory technologies. Although magnetics and optics readily lend themselves to two-dimensional realizations of spin texture, only recently have breakthroughs brought forth three-dimensional (3D) magnetic skyrmions, whereas their optical counterparts have eluded observation to date because their realization requires precise control over the spatiotemporal spectrum. Here, we demonstrate freely propagating 3D-localized optical skyrmionic structures with a non-trivial topological profile by imprinting meron polarization texture on open and closed spectral surfaces in the momentum-energy space of an ultrafast optical wave packet. Precise control over the spatiotemporal polarization texture of light – a key requisite for synthesizing 3D optical merons – is the product of synergy between novel methodologies in the modulation of light jointly in space and time, digital holography, and large-area birefringent metasurfaces. Our work advances the fields of polarization optics and topological photonics and may inspire new developments in imaging, metrology, optical communications, and quantum technologies. Recently, the increased capabilities in generating pulsed optical fields that are rigidly transported in linear media without diffraction or dispersion has opened the path to realisation of 3D optical skyrmionic structures. Here, the authors demonstrate 3D-localized optical merons by imprinting polarization textures onto the momentum-energy space of ultrafast light pulses.

Introducing elements into an optical cavity that modify the transverse spatial field structure can also impact the cavity spectral response. In particular, an intra-cavity spatial mode-converter is expected to induce modal runaway: unrestricted ladder-up in the modal order, concomitantly thwarting coherent field interference, thereby altogether suppressing the resonant response – a phenomenon that has yet to be observed in an optical cavity. Here we show that a single intra-cavity holographic phase mask placed in a compact free-standing planar Fabry-Pérot cavity renders the cavity spectral response resonance-free. By acting as a mode-converter on a basis of Laguerre-Gaussian (LG) modes, an incident broadband fundamental Gaussian mode exits the cavity in the form of a superposition of a large number of collinearly propagating broadband LG modes of fixed parity whose spectra coincide with that of the input. Crucially, the resonance-free spectral response is maintained while changing the cavity length by ~ 350%, raising the prospect of stable resonant optical sensors whose performance is impervious to length perturbations. Researchers demonstrate a resonance-free Fabry-Perot cavity using a single holographic phase mask. By converting Gaussian input into a broadband mix of Laguerre-Gaussian modes, the cavity remains stable despite  ~350% length changes, paving the way for highly reliable optical sensors.

Abstract Background Eosinophilic lung disease is a poorly understood inflammatory airway disease that results in substantial morbidity. Objective To describe clinical findings in dogs with eosinophilic lung disease defined on the basis of radiographic, bronchoscopic, and bronchoalveolar lavage fluid (BAL) analysis. Categories included eosinophilic bronchitis (EB), eosinophilic granuloma (EG), and eosinophilic bronchopneumopathy (EBP). Animals Seventy-five client owned dogs. Methods Medical records were retrospectively reviewed for dogs with idiopathic BAL fluid eosinophilia. Information abstracted included duration and nature of clinical signs, bronchoscopic findings, and laboratory data. Thoracic radiographs were evaluated for the pattern of infiltrate, bronchiectasis, and lymphadenomegaly. Results Thoracic radiographs were normal or demonstrated a bronchial pattern in 31 dogs assigned a diagnosis of EB. Nine dogs had intraluminal mass lesions and were bronchoscopically diagnosed with EG. The remaining 35 dogs were categorized as having EBP based on radiographic changes, yellow green mucus in the airways, mucosal changes, and airway collapse. Age and duration of cough did not differ among groups. Dogs with EB were less likely to have bronchiectasis or peripheral eosinophilia, had lower total nucleated cell count in BAL fluid, and lower percentage of eosinophils in BAL fluid compared to dogs in the other 2 groups. In contrast to previous reports, prolonged survival (>55 months) was documented in dogs with EG. Conclusions and Clinical Importance Dogs with eosinophilic lung disease can be categorized based on imaging, bronchoscopic and BAL fluid cytologic findings. Further studies are needed to establish response to treatment in these groups.

Invasive lionfish ( Pterois volitans/miles ) pose a serious threat to marine ecosystems throughout the western Atlantic Ocean and Caribbean Sea. The development of a fishery for lionfish has been proposed as a strategy for controlling populations; however, there is concern about consumption of this species by humans due to its high trophic position and potential for bioaccumulation of mercury. We analyzed total mercury (THg) in tissues of lionfish from two locations on the east coast of Florida. THg in lionfish increased with size and differed by location and sex. THg was highest in muscle tissue and was strongly positively correlated among tissues. THg in lionfish was lower than other commonly consumed marine fishes, and falls into Florida’s least restrictive advisory level. Consumption of lionfish poses a low risk and concerns over mercury bioaccumulation should not present a significant barrier to lionfish harvest.

Abstract Background Androgen-dependent cystinuria has been described in intact male dogs. Castration has been recommended to reduce urinary cystine excretion. Hypothesis/Objectives Urinary cystine/creatinine concentration will significantly decrease in dogs with suspected androgen-dependent (Type III) cystinuria after castration and will be associated with a lack of sonographic evidence of urolithiasis. Animals Six intact male dogs with cystine uroliths. Methods Prospective, observational study. Urinary amino acid/creatinine concentrations and abdominal ultrasound were evaluated at baseline (T0), 30 days (T30), and 90 days (T90) after castration and urolith removal. No dietary change was recommended unless urolith recurrence was noted. DNA was evaluated for the cystinuria-associated marker for Type III cystinuria. Results The median decline in urinary cystine/creatinine (uCys/creat) concentration from T0 to T30 was 577 nmol/mg (IQR, 415–969; p = 0.03), from T0 to T90 was 798 nmol/mg (IQR, 580–989; p = 0.03) and from T30 to T90 was 34 nmol/mg (IQR, 19.5–443; p = 0.03). Two dogs had small (2.5–3 mm) uroliths at T30, which resolved in one of them at T90. Both dogs with ultrasonographic evidence of recurrence at T30 were positive for the cystinuria-associated genetic marker, although no signs of lower urinary tract disease were noted in either dog. Three of 6 enrolled dogs were homozygous positive for the genetic marker. Conclusions and Clinical Importance Castration should be considered for intact male dogs with cystine urolithiasis.

Abstract Background Idiopathic inflammatory airway disease (IAD) in cats often is described as asthmatic (eosinophilic) or bronchitic (neutrophilic), but this designation requires collection of airway fluid and it fails to consider cats with mixed airway inflammation. Objective To identify clinical features that would differentiate inflammatory disease types. Animals Forty-nine cats with nonspecific airway inflammation identified by bronchoscopic bronchoalveolar lavage (BAL) between 2011 and 2018 were evaluated. Methods This is a retrospective study. Cats were categorized by BAL differential cytology as having eosinophilic (eosinophils >20% with neutrophils <14%, or eosinophils >50%), mixed (eosinophils 20%-50% and neutrophils >14% or discordant inflammation from 2 BAL sites), or neutrophilic (neutrophils >14% and eosinophils <20%) inflammation. Type and duration of presenting complaints, signalment, body condition score, respiratory rate, CBC results, bronchoscopy, BAL results (% recovery, total nucleated cell count, differential cell count), and radiographic findings were compared among groups. Results Idiopathic IAD was diagnosed in 49 cats, with BAL eosinophilic inflammation in 23, mixed inflammation in 14, and neutrophilic inflammation in 12. Cough was the predominant presenting complaint with no difference in duration of signs among groups (median, 5.5 months). Respiratory rate and effort also did not differ. Cats with eosinophilic inflammation were significantly younger (4.4 ± 3.3 years) than those with neutrophilic (8.0 ±5.6 years) or mixed inflammation (7.5 ± 4.0 years; P = .03). Results of CBC and interpretation of radiographic findings did not differ among groups. Conclusions and Clinical Importance Substantial overlap exists in clinical and radiographic findings in cats with various forms of idiopathic airway inflammation.

Domestic dog breeds exhibit remarkable morphological variations that result from centuries of artificial selection and breeding. Identifying the genetic changes that contribute to these variations could provide critical insights into the molecular basis of tissue and organismal morphogenesis. Bulldogs, French Bulldogs and Boston Terriers share many morphological and disease-predisposition traits, including brachycephalic skull morphology, widely set eyes and short stature. Unlike other brachycephalic dogs, these breeds also exhibit vertebral malformations that result in a truncated, kinked tail (screw tail). Whole genome sequencing of 100 dogs from 21 breeds identified 12.4 million bi-allelic variants that met inclusion criteria. Whole Genome Association of these variants with the breed defining phenotype of screw tail was performed using 10 cases and 84 controls and identified a frameshift mutation in the WNT pathway gene DISHEVELLED 2 (DVL2) (Chr5: 32195043_32195044del, p = 4.37 X 10-37) as the most strongly associated variant in the canine genome. This DVL2 variant was fixed in Bulldogs and French Bulldogs and had a high allele frequency (0.94) in Boston Terriers. The DVL2 variant segregated with thoracic and caudal vertebral column malformations in a recessive manner with incomplete and variable penetrance for thoracic vertebral malformations between different breeds. Importantly, analogous frameshift mutations in the human DVL1 and DVL3 genes cause Robinow syndrome, a congenital disorder characterized by similar craniofacial, limb and vertebral malformations. Analysis of the canine DVL2 variant protein showed that its ability to undergo WNT-induced phosphorylation is reduced, suggesting that altered WNT signaling may contribute to the Robinow-like syndrome in the screwtail breeds.

The primary aim of this study was to evaluate the effects of vasodilator administration on CT angiography (CTA) prostatic artery diameter and peak opacification in dogs with prostatic carcinoma prior to prostatic artery embolization (PAE). A prospective clinical trial was performed. Ten dogs with naturally occurring prostatic carcinoma and no evidence of cardiovascular disease were enrolled. Each dog underwent multiphase CTA of the prostate before and after IV vasodilator (glyceryl trinitrate [GTN] or clevidipine butyrate [clevidipine]) administration, and cardiovascular parameters were monitored. PAE was performed the following day. Prostatic arterial anatomy was characterized by CTA. Prostatic artery lumen diameter and peak opacification were measured on pre- and post-vasodilator CTA by a blinded radiologist. The percent change of these measurements was calculated and assessed for significance. Glyceryl trinitrate and clevidipine were administered in 5 dogs each with subsequent blood pressure reduction documented in all dogs. No significant difference was detected in prostatic artery diameter or peak opacification between pre- vs. post-vasodilator CTA. Good agreement in prostatic arterial branch number, origin, and course was documented between pre- and post-vasodilator CTA images. Study findings do not support the routine use of vasodilator administration during pre-PAE CTA in dogs, though larger sample sizes and protocol alterations may be needed to detect a clinically relevant utility.

Abstract Background Aspiration pneumonia (AP) and bronchopneumonia (BP) are poorly characterized diseases in cats that share clinical similarities to inflammatory airway disease (IAD). Objectives Describe clinicopathologic, radiographic, and microbiologic features in cats with AP and BP and compare findings to those in cats with IAD. Animals Thirty-three cats with AP and 26 with BP; 44 cats with IAD. Methods Retrospective case-control study. Results extracted for all cats included signalment, physical examination findings, historical details, and potential risk factors for aspiration. Diagnostic test results were summarized including CBC, bronchoalveolar (BAL) fluid analysis and microbial culture. Radiographs were reviewed in masked fashion and scored for severity. Results of BAL fluid analysis were assessed for evidence of septic inflammation. Results Cats with AP were less likely to be presented for evaluation of cough (P < .001) and more likely to be hypothermic (P = .01) than were cats with IAD or BP. Median duration of signs was significantly shorter in cats with AP (12 days) compared to cats with BP or IAD (270 and 180 days; P = .01). Radiographically, cats with AP were more likely to have an alveolar pattern and higher total score than were cats with BP or IAD. Mycoplasma spp. were the organisms most commonly cultured from BAL fluid in cats with BP, but were not cultured from any cats with AP. Conclusion and Clinical Importance Pneumonia must be distinguished from IAD in cats with cough and AP should be considered in cats with acute onset of tachypnea.