Excitons in type-II quantum dots: Finite offsets

Quantum size effects for an exciton attached to a spherical quantum dot are calculated by a variational approach. The band line-ups are assumed to be type-II with finite offsets. The dependence of the exciton binding energy upon the dot radius and the offsets is studied for different sets of electron and hole effective masses

Binding Energy of Hydrogen-Like Impurities in Quantum Well Wires of InSb/GaAs in a Magnetic Field

The binding energy of a hydrogen-like impurity in a thin size-quantized wire of the InSb/GaAs semiconductors with Kane’s dispersion law in a magnetic fieldBparallel to the wire axis has been calculated as a function of the radius of the wire and magnitude ofB, using a variational approach. It is shown that when wire radius is less than the Bohr radius of the impurity, the nonparabolicity of dispersion law of charge carriers leads to a considerable increase of the binding energy in the magnetic field, as well as to a more rapid growth of binding energy with growth ofB

The neurobiology of Etruscan shrew active touch

The Etruscan shrew, Suncus etruscus, is not only the smallest terrestrial mammal, but also one of the fastest and most tactile hunters described to date. The shrew's skeletal muscle consists entirely of fast-twitch types and lacks slow fibres. Etruscan shrews detect, overwhelm, and kill insect prey in large numbers in darkness. The cricket prey is exquisitely mechanosensitive and fast-moving, and is as big as the shrew itself. Experiments with prey replica show that shape cues are both necessary and sufficient for evoking attacks. Shrew attacks are whisker guided by motion- and size-invariant Gestalt-like prey representations. Shrews often attack their prey prior to any signs of evasive manoeuvres. Shrews whisk at frequencies of approximately 14 Hz and can react with latencies as short as 25–30 ms to prey movement. The speed of attacks suggests that shrews identify and classify prey with a single touch. Large parts of the shrew's brain respond to vibrissal touch, which is represented in at least four cortical areas comprising collectively about a third of the cortical volume. Etruscan shrews can enter a torpid state and reduce their body temperature; we observed that cortical response latencies become two to three times longer when body temperature drops from 36°C to 24°C, suggesting that endothermy contributes to the animal's high-speed sensorimotor performance. We argue that small size, high-speed behaviour and extreme dependence on touch are not coincidental, but reflect an evolutionary strategy, in which the metabolic costs of small body size are outweighed by the advantages of being a short-range high-speed touch and kill predator

Short-time dynamic patterns of bioaerosol generation and displacement in an indoor environment

Short-time dynamics and distribution of airborne biological and total particles were assessed in a large university hallway by particle counting using laser particle counters and impaction air samplers. Particle numbers of four different size ranges were determined every 2 minutes over several hours. Bioaerosols (culturable bacteria and fungi determined as colony-forming units) were directly collected every 5 minutes on Petri dishes containing the corresponding growth medium. Results clearly show distinct shorttime dynamics of particulate aerosols, both of biological and non-biological origin. These reproducible periodic patterns are closely related to periods when lectures are held in lecture rooms and the intermissions in between where students are present in the hallway. Peaks of airborne culturable bacteria were observed with a periodicity of 1 hour. Bioaerosol concentrations follow synchronously the variation in total number of particles. These highly reproducible temporal dynamics have to be considered when monitoring indoor environments with respect to air quality

Amphetamine-Like Analogues in Diabetes: Speeding towards Ketogenesis

Obesity is common in patients with type 1 and type 2 diabetes. Amphetamine-like analogues comprise the most popular class of weight loss medications. We present a case of a 34-year-old African American female with a history of type 1 diabetes, dyslipidemia, and obesity who developed diabetic ketoacidosis (DKA) after starting Diethylpropion for the purpose of weight loss. Shortly after starting Diethylpropion, she developed nausea, vomiting, and periumbilical pain. Blood work revealed glucose of 718 mg/dL, pH 7.32 (7.35–7.45), bicarbonate 16 mmol/L (22–29 mmol/L), and anion gap 19 mmol/L (8–16 mmol/L). Urine analysis demonstrated large amount of ketones. She was hospitalized and successfully treated for DKA. Diethylpropion was discontinued. Amphetamine-like analogues administration leads to norepinephrine release from the lateral hypothalamus which results in the appetite suppression. Peripheral norepinephrine concentration rises as well. Norepinephrine stimulates adipocyte lipolysis and thereby increases nonesterified fatty acids (NEFA) availability. It promotes β-oxidation of NEFA to ketone bodies while decreasing metabolic clearance rate of ketones. In the setting of acute insulin deficiency these effects are augmented. Females are more sensitive to norepinephrine effects compared to males. In conclusion, amphetamine-like analogues lead to a release of norepinephrine which can result in a clinically significant ketosis, especially in the setting of insulin deficiency

Dual Paraneoplastic Endocrine Syndromes Heralding Onset of Extrapulmonary Small Cell Carcinoma: A Case Report and Narrative Review

ObjectiveExtrapulmonary small cell carcinoma (EPSCC) is rare and frequent metastases at presentation can complicate efforts to identify a site of origin. In particular, SCC comprises <1% of prostate cancers and has been implicated in castration resistance.MethodsClinical, laboratory, imaging, and pathology data are presented.ResultsA 56-year-old man with locally advanced prostate adenocarcinoma on androgen deprivation therapy presented with a clogged nephrostomy tube. Laboratory results included calcium 13.8 mg/dL (8.5–10.5 mg/dL), albumin 3.6 g/dL (3.5–5 mg/dL), and potassium 2.8 mmol/L (3.5–5.2 mmol/L). Hypercalcemia investigation revealed intact PTH 19 pg/mL (16–87 pg/mL), 25-OH vitamin D 15.7 ng/mL (>30 ng/mL), and PTH-related peptide (PTHrP) 63.4 pmol/L (<2.3 pmol/L). Workup for hypokalemia yielded aldosterone 5.3 ng/dL (<31 ng/dL), renin 0.6 ng/mL/h (0.5–4 ng/mL/h), and 6:00 a.m. cortisol 82 µg/dL (6.7–22.6 µg/dL) with ACTH 147 pg/mL (no ref. range). High-dose Dexamethasone suppression testing suggested ACTH-dependent ectopic hypercortisolism. Contrast-enhanced CT findings included masses in the liver and right renal pelvis, a heterogeneous enlarged mass in the region of the prostate invading the bladder, bilateral adrenal thickening, and lytic lesions in the pelvis and spine. Liver biopsy identified epithelioid malignancy with Ki proliferation index 98% and immunohistochemical staining positive for synaptophysin and neuron-specific enolase, compatible with high-grade small cell carcinoma. Staining for ACTH was negative; no stain for CRH was available. Two weeks after chemotherapy, 6:00 a.m. cortisol normalized and CT scans showed universal improvement.ConclusionExtensive literature details paraneoplastic syndromes associated with SCC, but we report the first case of EPSCC diagnosed due to onset of dual paraneoplastic syndromes

Air pollution and respiratory health of children: the PEACE panel study in Prague, Czech Republic.

A multicentre study (Pollution Effects on Asthmatic Children in Europe (PEACE)) project investigated the relationship between the air pollution and daily variation of respiratory health in children with chronic respiratory symptoms. Data were collected on 66 children in Prague and 68 children in Benesov, Czech Republic. The panels were followed from January 17 to April 12, 1994. Respiratory symptoms and peak expiratory flow were recorded on a daily basis in a diary. Ambient air pollutants as well as meteorological parameters were measured at local monitoring stations on a daily basis. Mean particles with a 50% cut-off aerodynamic diameter of 10 μm (PM10) (SO2) levels were 53 (114) μg.m-3 and 50 (31) μg.m-3 in Prague and Benesov, respectively. The association between air pollution and health outcomes was analysed using time series regression models. Between air pollution and symptom prevalence a small association was found, also between air pollution and prevalence of medication use. No association of air pollution and peak flow or between air pollution and respiratory symptom incidence indicating an adverse effect could be detected. In conclusion, a small effect of air pollution on the prevalence of respiratory symptoms and medication use was detected

Characterisation of indoor particulate matter – Influence of indoor and outdoor sources

Μη διαθέσιμη περίληψηNot available summarizationΠαρουσιάστηκε στο: European Aerosol Conferenc