Generation of integer and fractional vortex beams based on liquid crystal electronically reconfigurable spiral phase plates.

The manufacturing and characterization of a large-size 72-electrode liquid crystal-based reconfigurable spiral phase plate (SPP) is presented. The SPP is addressed by a custom-made driver with 72 independent channels, which allows for the generation of any arbitrary integer or fractional optical vortex beam with topological charges ranging from -24 to +24. The 25 mm diameter device is fabricated using direct laser writing, leading to a fill factor over 99%. The device performance and flexibility exceed previous transparent reconfigurable SPP in terms of size, tuning range, and fill factor. The device and the light path have been simulated using the angular spectrum propagation method, showing excellent correspondence.

Reconfigurable perfect vortex beam generator based on a liquid crystal spiral phase plate.

A transmissive adaptable optical setup to generate a range of perfect vortex beams (PVBs) carrying different topological charges (TC) without using moving parts is presented. The setup is composed of an ad hoc transparent reconfigurable liquid crystal (LC) spiral phase plate (SPP), a refractive axicon and a convergent refractive lens. The LC SPP electrodes are manufactured ablating indium-tin oxide (ITO) glass substrates using direct laser writing (DLW) resulting in a very high fill factor device. In-house tailored electronics drive the 72 LC SPP electrodes giving rise to 72 different configurations with orbital angular momentum. In this work, the generation of PVBs with 36 positive or 36 negative TCs using this optical setup is accomplished.

Flourishing During the COVID-19 Pandemic: A Longitudinal Study in South Africa.

In this longitudinal study, we examine changes in psychological distress and multidimensional well-being from before to during the COVID-19 pandemic among South African adults. As a secondary purpose, we explore whether pre-pandemic flourishing is protective against subsequent psychological distress during the public health crisis. The analytic sample (n = 293; Mage = 44.27, SD = 14.28; female = 65.19%) completed measures of anxiety symptoms, depression symptoms, and well-being shortly before the stringent nationwide lockdown started in South Africa (T1). A follow-up assessment was completed approximately 6 months later (T2). Paired samples t-tests supported very small improvements in anxiety (d = -0.09) and depression symptoms (d = -0.13). For domains of well-being, small increases were found in close social relationships (d = 0.25) and financial and material stability (d = 0.19). Positive changes in the domains of character and virtue (d = 0.10) and meaning and purpose (d = 0.07) were very small. Changes in physical and mental health (d = -0.03) and life satisfaction and happiness (d = 0.02) were more negligible. Results from the generalized linear models indicated that continuous scores of secure flourishing assessed before the COVID-19 pandemic were associated with lower subsequent psychological distress (particularly depression symptoms) during the public health crisis. We discuss the implications of the findings for the development and delivery of interventions to promote and sustain human flourishing during public health crises, especially in contexts of social-structural vulnerability.

Positron emission tomography and its role in the assessment of vulnerable plaques in comparison to other imaging modalities.

The diagnosis and management of vulnerable plaques are topics of high interest in the cardiovascular field. Although imaging techniques like computed tomography angiography (MCTA) and ultrasonography (USG) can structurally evaluate atherosclerotic plaques, they are limited in examining internal cellular processes. Positron emission tomography (PET) molecular imaging, on the other hand, can highlight these cellular processes, including inflammation, angiogenesis, and lipid oxidation. Magnetic resonance imaging (MRI) is also a valuable non-invasive imaging technique that can provide detailed anatomical and functional information on the cardiovascular system. In this review, we compare the advantages and drawbacks of MCTA, USG and MRI imaging techniques with PET molecular imaging in evaluating vulnerable plaques. PET imaging allows physicians to measure different pathophysiological events within the plaque using intravenous radiotracers, of which 18F-fluorodeoxyglucose (18F-FDG) is the most validated one. By using 18F-FDG, physicians can understand the formation of the plaque, assess the accumulation of macrophages, and predict major cardiovascular events. However, some limitations exist in using 18F-FDG, including myocardial uptake and low sensitivity in imaging coronary arteries. We also mention other radiotracers that can help in evaluating vulnerable plaques, including 18F-NaF. Although PET imaging is still challenging, it has shown promise in evaluating vulnerable plaques and could be used to intervene in high-risk patients before major cardiovascular events occur.

Influence of low concentrations of an acid preservative on sponge cakes under different storage conditions.

In a previous study, we demonstrated the efficiency of an acid test preservative at concentrations higher than 10 g/kg of product. The aim of the current study has been to assay, in a pilot plant, a preservative at lower and different doses than tested in the aforementioned study, in contrast with different storage temperature and relative humidity (RH) conditions and to check the possibilities of the growth of molds with a toxigenic capacity. The effect of the test preservative is not demonstrable at very low concentrations, as occurs in batch 2. In this case, the influence of the other storage parameters, temperature and RH, has a mixed effect, which makes it difficult to draw conclusions about the convenience of the preservative. In our opinion, the minimal concentration of the test preservative to reach readable results is 4 g/kg, but it is not enough to guarantee a longer shelf life. Regarding the mycotoxigenic study, the majority of molds obtained in the isolations from the cakes after their macroscopic identification corresponded to the genera Aspergillus and Penicillium. Only 5 turned out to be mycotoxigenic, with citrinin and viridicatumtoxin being detected.

Prenatal growth of the human mandibular condylar cartilage.

The question of whether the condylar cartilage possesses a growth potential like that of the long bone growth plates has been the subject of contrasting viewpoints. We have recently established that the thickness of the human tibial growth plate progressively decreases during the second half of the fetal period, but that the changes in the total human condylar thickness do not correlate with fetal age or weight. The present study examined the change in the thickness of the human mandibular condyle layers during the fetal growth of the mandible. Mandibles were obtained from autopsy of 19 human fetuses ranging in fetal age from 18 to 41 weeks. The total length of the mandible, the lengths of the mandibular body and of the ramus were measured, as well as the gonial angles. The total thickness of the condyle, and the thickness of the articular, progenitor, cartilage, chondroblast, and hypertrophic chondrocyte layers were measured on the central segment of central sagittal sections of the mandibular condylar cartilage. The total mandible, the corpus and the ramus lengths increased linearly with the age of the fetus and they all correlated strongly with fetal weight. However, changes in the total condylar thickness and in the thickness of the cartilage layer (chondroblast plus hypertrophic chondrocytes) did not correlate with fetal weight or mandibular length. The thickness of the articular layer increased with weight, but changes in the progenitor layer were independent of corporal and mandibular growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Solitary fibrous tumor of the mesentery.

We report a solitary fibrous tumor of the abdominal cavityt that presented as a encapsulated mass attached to the mesentery in a 33-yr-old man. Histologically, the lesion showed a disorganized arrangement of spindle cells in a collagenous background and prominent vascular channels of varying size. Tumor cells showed immunohistochemical reactivity for vimentin only. Cytokeratins and CD34 were negative. This report further extends the anatomic range of solitary fibrous tumor, a neoplasm that must be included in the differential diagnosis of well-defined abdominal masses. The behavior of this mesenteric solitary fibrous tumor has been benign.