The formation of glycocyamine in man and its urinary excretion

Glycocyamine was first isolated from human and dog urine and identified by Weber (1-3). He supported the view that glycocyamine is a normal precursor of creatine and that its appearance in urine (2) is “an overflow phenomenon of an intermediate metabolic product ...” He expressed no views on the mechanism of its formation

Bugs and Brains: The Microbiome & Dementia

Interest in the microbiome and its correlation with different neurological diseases has grown significantly over the past decade. The gut microbiome contains a vast array of diverse organisms living in the gastrointestinal (GI) tract. Predominantly composed of bacteria, the gut microbiome helps regulate homeostasis and metabolism in the host, aiding in immune system development as well as vitamin and nutrient absorption. Studies suggest that, in addition to providing humans with these physiological benefits, the gut microbiome is also linked to and communicates with the brain via the gut-brain axis (GBA). Long-standing research on the GBA has demonstrated that the GI tract and the central nervous system are interconnected through both neurological and immunological signaling pathways. Recent research is expanding our understanding of the microbiome and the GBA, revealing correlations between the microbiome impact on the GBA and neurological conditions such as Alzheimer’s dementia and Lewy body dementia, going as far as to identify and highlight specific microbial species that may serve as risk or protective factors for various forms of dementia. This letter aims to highlight the current findings and recommend the use of tools such as microbial cell-free DNA testing to gain a better understanding of the role of gut dysbiosis in dementia patients

A 275–425-GHz Tunerless Waveguide Receiver Based on AlN-Barrier SIS Technology

We report on a 275–425-GHz tunerless waveguide receiver with a 3.5–8-GHz IF. As the mixing element, we employ a high-current-density Nb–AlN–Nb superconducting–insulating– superconducting (SIS) tunnel junction. Thanks to the combined use of AlN-barrier SIS technology and a broad bandwidth waveguide to thin-film microstrip transition, we are able to achieve an unprecedented 43% instantaneous bandwidth, limited by the receiver's corrugated feedhorn. The measured double-sideband (DSB) receiver noise temperature, uncorrected for optics loss, ranges from 55 K at 275 GHz, 48 K at 345 GHz, to 72 K at 425 GHz. In this frequency range, the mixer has a DSB conversion loss of 2.3 1 dB. The intrinsic mixer noise is found to vary between 17–19 K, of which 9 K is attributed to shot noise associated with leakage current below the gap. To improve reliability, the IF circuit and bias injection are entirely planar by design. The instrument was successfully installed at the Caltech Submillimeter Observatory (CSO), Mauna Kea, HI, in October 2006

Diagnostic accuracy of qPCR and microscopy for cutaneous leishmaniasis in rural Ecuador: A Bayesian latent class analysis

Precisión diagnóstica; Leishmaniasis cutánea; Ecuador ruralPrecisió diagnòstica; Leishmaniosi cutània; Equador ruralDiagnostic accuracy; Cutaneous leishmaniasis; Rural EcuadorBackground Clinical and laboratory diagnosis of cutaneous leishmaniasis (CL) is hampered by under-ascertainment of direct microscopy. Methods This study compared the diagnostic accuracy of qPCR on DNA extracted from filter paper to the accuracy of direct smear slide microscopy in participants presenting with a cutaneous lesion suspected of leishmaniasis to 16 rural healthcare centers in the Ecuadorian Amazon and Pacific regions, from January 2019 to June 2021. We used Bayesian latent class analysis to estimate test sensitivity, specificity, likelihood ratios (LR), and predictive values (PV) with their 95% credible intervals (95%CrI). The impact of sociodemographic and clinical characteristics on predictive values was assessed as a secondary objective. Results Of 320 initially included participants, paired valid test results were available and included in the diagnostic accuracy analysis for 129 from the Amazon and 185 from the Pacific region. We estimated sensitivity of 68% (95%CrI 49% to 82%) and 73% (95%CrI 73% to 83%) for qPCR, and 51% (95%CrI 36% to 66%) and 76% (95%CrI 65% to 86%) for microscopy in the Amazon and Pacific region, respectively. In the Amazon, with an estimated disease prevalence among participants of 73%, negative PV for qPCR was 54% (95%CrI 5% to 77%) and 44% (95%CrI 4% to 65%) for microscopy. In the Pacific, (prevalence 88%) the negative PV was 34% (95%CrI 3% to 58%) and 37% (95%CrI 3% to 63%). The addition of qPCR parallel to microscopy in the Amazon increases the observed prevalence from 38% to 64% (+26 (95%CrI 19 to 34) percentage points). Conclusion The accuracy of either qPCR on DNA extracted from filter paper or microscopy for CL diagnosis as a stand-alone test seems to be unsatisfactory and region-dependent. We recommend further studies to confirm the clinically relevant increment found in the diagnostic yield due to the addition of qPCR

Structure and functional relevance of the Slit2 homodimerization domain

Slit proteins are secreted ligands that interact with the Roundabout (Robo) receptors to provide important guidance cues in neuronal and vascular development. Slit–Robo signalling is mediated by an interaction between the second Slit domain and the first Robo domain, as well as being dependent on heparan sulphate. In an effort to understand the role of the other Slit domains in signalling, we determined the crystal structure of the fourth Slit2 domain (D4) and examined the effects of various Slit2 constructs on chick retinal ganglion cell axons. Slit2 D4 forms a homodimer using the conserved residues on its concave face, and can also bind to heparan sulphate. We observed that Slit2 D4 frequently results in growth cones with collapsed lamellipodia and that this effect can be inhibited by exogenously added heparan sulphate. Our results show that Slit2 D4–heparan sulphate binding contributes to a Slit–Robo signalling mechanism more intricate than previously thought

'Magic coins' and 'magic squares': the discovery of astrological sigils in the Oldenburg Letters

Enclosed in a 1673 letter to Henry Oldenburg were two drawings of a series of astrological sigils, coins and amulets from the collection of Strasbourg mathematician Julius Reichelt (1637–1719). As portrayals of particular medieval and early modern sigils are relatively rare, this paper will analyse the role of these medals in medieval and early modern medicine, the logic behind their perceived efficacy, and their significance in early modern astrological and cabalistic practice. I shall also demonstrate their change in status in the late seventeenth century from potent magical healing amulets tied to the mysteries of the heavens to objects kept in a cabinet for curiosos. The evolving perception of the purpose of sigils mirrored changing early modern beliefs in the occult influences of the heavens upon the body and the natural world, as well as the growing interests among virtuosi in collecting, numismatics and antiquities

Robert P. T. Coffin Correspondence

Entries include letters on Wells and Bowdoin College stationery, a secret baked smelt recipe, a biographical review clipping from the Maine Library Bulletin, some transcripts of inscriptions, a newspaper award clipping with Coffin\u27s photographic image, newspaper review clippings with Coffin\u27s drawn and photographed portrait and a book image, correspondence about poems and readings on Maine State Library stationery, a hand written note from Coffin\u27s wife, several poems: the setting for the poem This is My Country and a newspaper clipping describing the shoreline play area of Coffin\u27s youth near Ragged Island, owned at the time of printing by Edna St. Vincent Millay, and a changeless dispute with the Maine Author Collection book gift policy of the Maine State Library that ... things that are free, are lightly esteemed ..