Architects and engineers are beginning to consider a new dimension of indoor air: the structure and composition of airborne microbial communities. A first step in this emerging field is to understand ...the forces that shape the diversity of bioaerosols across space and time within the built environment. In an effort to elucidate the relative influences of three likely drivers of indoor bioaerosol diversity – variation in outdoor bioaerosols, ventilation strategy, and occupancy load – we conducted an intensive temporal study of indoor airborne bacterial communities in a high‐traffic university building with a hybrid HVAC (mechanically and naturally ventilated) system. Indoor air communities closely tracked outdoor air communities, but human‐associated bacterial genera were more than twice as abundant in indoor air compared with outdoor air. Ventilation had a demonstrated effect on indoor airborne bacterial community composition; changes in outdoor air communities were detected inside following a time lag associated with differing ventilation strategies relevant to modern building design. Our results indicate that both occupancy patterns and ventilation strategies are important for understanding airborne microbial community dynamics in the built environment.
Driving assistance technology has gained traction in recent years and is becoming more widely used in vehicles. However, drivers usually experience a reduced sense of agency when driving assistance ...is active even though automated assistance improves driving performance by reducing human error and ensuring quick reactions. The present study examined whether driving assistance can maintain human sense of agency during early deceleration in the face of collision risk, compared with manual deceleration. In the experimental task, participants decelerate their vehicle in a driving simulator to avoid collision with a vehicle that suddenly cut in front of them and decelerated. In the assisted condition, the system performed deceleration 100 ms after the cut-in. Participants were instructed to decelerate their vehicle and follow the vehicle that cut-in. This design ensured that the deceleration assistance applied a similar control to the vehicle as the drivers intended to, only faster and smoother. Participants rated their sense of agency and their driving performance. The results showed that drivers maintained their sense of agency and improved driving performance under driving assistance. The findings provided insights into designing driving assistance that can maintain drivers’ sense of agency while improving future driving performance. It is important to establish a mode of joint-control in which the system shares the intention of human drivers and provides improved execution of control.
We have developed a neural network model capable of performing visual binding inspired by neuronal circuitry in the optic glomeruli of flies: a brain area that lies just downstream of the optic lobes ...where early visual processing is performed. This visual binding model is able to detect objects in dynamic image sequences and bind together their respective characteristic visual features—such as color, motion, and orientation—by taking advantage of their common temporal fluctuations. Visual binding is represented in the form of an inhibitory weight matrix which learns over time which features originate from a given visual object. In the present work, we show that information represented implicitly in this weight matrix can be used to explicitly count the number of objects present in the visual image, to enumerate their specific visual characteristics, and even to create an enhanced image in which one particular object is emphasized over others, thus implementing a simple form of visual attention. Further, we present a detailed analysis which reveals the function and theoretical limitations of the visual binding network and in this context describe a novel network learning rule which is optimized for visual binding.
Visual binding is the process of associating the responses of visual interneurons in different visual submodalities all of which are responding to the same object in the visual field. Recently ...identified neuropils in the insect brain termed
optic glomeruli
reside just downstream of the optic lobes and have an internal organization that could support visual binding. Working from anatomical similarities between optic and olfactory glomeruli, we have developed a model of visual binding based on common temporal fluctuations among signals of independent visual submodalities. Here we describe and demonstrate a neural network model capable both of refining selectivity of visual information in a given visual submodality, and of associating visual signals produced by different objects in the visual field by developing inhibitory neural synaptic weights representing the visual scene. We also show that this model is consistent with initial physiological data from optic glomeruli. Further, we discuss how this neural network model may be implemented in optic glomeruli at a neuronal level.
Background
Our goal was to study the utility of the routine use of the Gomori iron stain in the evaluation of leg biopsies of inflammatory lesions.
Methods
One hundred consecutive skin biopsies from ...the legs were evaluated with hematoxylin and eosin and Gomori iron stains. Iron positivity was semi‐quantitatively graded from trace to 4+.
Results
Forty‐two (42) cases were positive with the Gomori iron stain as follows: stasis dermatitis (14), Schamberg's disease (7), folliculitis (2), psoriasis (2), trauma (2), arthropod bite (2), allergic contact dermatitis (2), lichen simplex chronicus (1), senile purpura (1), vascular ectasia (1), lobular capillary hemangioma (1), scar (1), pretibial pigmented patches (1), tinea (1), lentigo maligna (1), traumatic fat necrosis (1), lichen planus (1) and fixed drug eruption (1). Twelve of 14 cases of stasis dermatitis had 2+ or greater iron staining; 8 cases were 3+ or 4+. All other diagnoses had trace or 1+ staining for iron except for one scar (2+). One of 19 samples (5.3%) of ‘normal’ leg skin controls showed iron stain positivity, and was graded as trace.
Conclusions
After correcting for iron staining in 5.3% of normal leg skin controls, we observed Gomori iron positivity in 36.7% of 100 consecutive leg biopsies. We suggest that routine application of an iron stain on biopsies of dermatoses from the legs is useful. Stasis dermatitis and Schamberg's disease are the most frequent iron positive diagnoses, and the diagnosis is aided by the pattern of hemosiderin deposition. Negative iron stain is also useful in suggesting the presence of melanin pigment in macrophages in lichenoid and other dermatoses. To confirm a truly negative iron stain, study of the section at ×400 rather than ×100 is recommended.
Cutaneous squamous cell carcinoma (SCC) has been classified into a large number of subtypes, which have been grouped according to malignant potential. We describe a new morphological variant ...containing areas of intermingled cytotrophoblast-like and syncytiotrophoblast-like cells and designate it "choriocarcinoma-like SCC." Furthermore, the neoplasm exhibits expression of human chorionic gonadotropin predominantly in the syncytiotrophoblast-like foci, mimicking the germ cell tumor. Human chorionic gonadotropin expression has been described in SCC from other organs, but not by cutaneous SCC, to our knowledge. This new variant could be misinterpreted as metastatic choriocarcinoma, especially in small punch biopsies. The frequency of this neoplasm and its malignant potential are undetermined.
Xanthomas of the skin may mimic balloon cell melanoma because 1) both lesions may exhibit a diffuse dermal proliferation of cytologically similar large vacuolated or clear cells with distinct ...cytoplasmic membranes, 2) dermal maturation (smaller deep dermal nuclei) is absent in both lesions, 3) melanin pigment is usually absent in balloon cell melanoma, 4) cellular atypia may be minimal in balloon cell melanoma, and 5) mitoses may be absent or rare in balloon cell melanoma. We report a unique xanthoma, which further simulated melanoma by exhibiting epidermotropism and a pseudonesting pattern at the dermal-epidermal junction. The correct diagnosis was made with an immunohistochemical panel revealing tumor cell positivity for CD68 and negativity for S-100 protein and MART-1. Immunohistochemical studies may be required in the critical differential diagnosis of epidermotropic xanthoma and amelanotic balloon cell melanoma.
Combined mastocytoma-junctional nevus Northcutt, Alan D; Tschen, Jaime A
The American journal of dermatopathology,
12/2004, Letnik:
26, Številka:
6
Journal Article
Recenzirano
A unique combined mastocytoma-junctional nevus presented as a 4-mm dark brown macule in the axilla of a 57-year-old white female. Histopathologic examination revealed a proliferation of mast cells ...partially or completely filling the dermal papillae, hyperpigmentation of the basal keratinocytes and mildly increased basal melanocytes. Overlying the mast cell proliferation, pigmented junctional nevus nests were present. The mast cells were strongly positive with Giemsa stain and mast cell tryptase immunohistochemical stain; nevomelanocytic cells were negative. Nevomelanocytes were strongly immunoreactive for S100, HMB-45, Mart-1, and tyrosinase; mast cells were negative. The clinicopathologic features suggested a synchronous proliferation of 2 cell types in the same small cutaneous field rather than a collision tumor. While the cutaneous mast cells probably originated as a disseminated clone, it is postulated that local mast cell growth factor induced nevomelanocytic proliferation and modulated mast cell growth. In fact, the tumor exhibited strong immunoreactivity for the mast cell growth factor receptor (CD117) in mast cells, basal melanocytes, and nevus nests. The incidence of dual mast cell-melanocytic tumors appears to be very low, as only 3 total cases have now been reported. However, since in patients with multiple mastocytomas only a small fraction of lesions are biopsied, the true incidence may be higher than supposed.
Axillary granular parakeratosis Northcutt, A D; Nelson, D M; Tschen, J A
Journal of the American Academy of Dermatology
24, Številka:
4
Journal Article
Recenzirano
The term axillary granular parakeratosis is proposed for a unique axillary eruption with distinct histopathologic features. Four middle-aged to elderly patients (three women, one man) had unilateral ...or bilateral, usually pruritic, hyperpigmented to bright red patches in the axillae. Biopsy specimens revealed severe compact parakeratosis with the stratum corneum measuring 80 to 250 microns in maximal thickness, maintenance of the stratum granulosum, remarkable retention of keratohyaline granules throughout the stratum corneum, and vascular proliferation and ectasia. A contact reaction to an antiperspirant/deodorant is suspected as the cause. We speculate that the offending agent alters the maturation sequence of the stratum granulosum and stratum corneum, possibly by interfering with the degradation of filaggrin precursor to filaggrin units.
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