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International audience; Results from the Sample Analysis at Mars (SAM)-evolved gas analyzer (EGA) on board the Mars Science Laboratory Curiosity rover constrained the alteration history and habitability potential of rocks sampled across the Siccar Point unconformity in Gale crater.The Glasgow member (Gm) mudstone just below the unconformity had evidence of acid sulfate or Si-poor brine alteration of Fe-smectite to Fe amorphous phases, leaching loss of Fe-Mg-sulfate and exchange of unfractionated sulfur 34S (δ34S=2±7‰) with enriched 34S (20±5‰, V-CDT). Carbon abundances did not significantly change (322-661 μgC/g) consistent with carbon stabilization by amorphous Al- and Fe-hydroxide phases. The Gm mudstone had no detectable oxychlorine and extremely low nitrate. Nitrate (0.06 wt.% NO3), oxychlorine (0.13 wt% ClO4), high C (1472 μg C/g), and low Fe/Mg-sulfate concentration (0.24 wt.% SO3) depleted in 34S (δ34S = -27‰ ± 7), were detected in the Stimson formation (Sf) eolian sandstone above the unconformity. Redox disequilibrium through the detections of iron sulfide and sulfate supported limited aqueous processes in the Sf sandstone. Si-poor brines or acidic fluids altered the Gm mudstone just below the unconformity but did not alter underlying Gm mudstones further from the contact. Chemical differences between the Sf and Gm rocks suggested that fluid interaction was minimal between the Sf and Gm rocks. These results suggested that the Gm rocks were altered by subsurface fluids after the Sf placement. Aqueous processes along the unconformity could have provided habitable conditions and in some cases, C and N levels could have supported heterotrophic microbial populations.

Curiosity, the Mars Science Laboratory (MSL) rover, landed on Mars in August 2012 to investigate the ~3.5-billion-year-old (Ga) fluvio-lacustrine sedimentary deposits of Aeolis Mons (informally known as Mount Sharp) and the surrounding plains (Aeolis Palus) in Gale crater. After nearly nine years, Curiosity has traversed over 25 km, and the Chemistry and Mineralogy (CheMin) X-ray diffraction instrument on-board Curiosity has analyzed 30 drilled rock and three scooped soil samples to date. The principal strategic goal of the mission is to assess the habitability of Mars in its ancient past. Phyllosilicates are common in ancient Martian terrains dating to ~3.5–4 Ga and were detected from orbit in some of the lower strata of Mount Sharp. Phyllosilicates on Earth are important for harboring and preserving organics. On Mars, phyllosilicates are significant for exploration as they are hypothesized to be a marker for potential habitable environments. CheMin data demonstrate that ancient fluvio-lacustrine rocks in Gale crater contain up to ~35 wt. % phyllosilicates. Phyllosilicates are key indicators of past fluid–rock interactions, and variation in the structure and composition of phyllosilicates in Gale crater suggest changes in past aqueous environments that may have been habitable to microbial life with a variety of possible energy sources.

Akaganeite, a Cl-bearing Fe(III) (hydr)oxide, has been reported in several locations on Mars, including Yellowknife Bay in Gale crater and Robert Sharp crater, but formation conditions remain unknown. We investigated akaganeite precipitation as a function of solution pH and chloride concentration. Akaganeite was synthesized through hydrolysis of Fe(III) perchlorate in the presence of 0.02, 0.05 and 0.1 M chloride and at initial solution pH of 1.6, 4, 6 and 8 at 90 deg C. Mineralogy of the precipitated Fe(III) (hydr)oxides was characterized by X-ray diffraction (XRD), infrared spectroscopy and Mossbauer spectroscopy and total chloride and perchlorate contents were determined by ion chromatography. XRD revealed that akaganeite formed alone or in mixtures with ferrihydrite, hematite and/or goethite at initial pH 1.6 with 0.02, 0.05 and 0.1 M Cl- and at initial pH from 4 to 8 with 0.05 and 0.1 M Cl-. Mossbauer parameters for akaganeite and ferrihydrite were similar to nanophase Fe(III) oxide reported on Mars. Infrared analysis revealed that akaganeite bands at ~2 and ~2.45 μm were sensitive to amount of akaganeite, total chloride content and presence of other Fe(III) (hydr)oxides. The obtained results indicate that akaganeite in Yellowknife Bay likely formed under acidic to alkaline (1.6 0.05 M Cl- by the dissolution of basaltic minerals. Akaganeite in Robert Sharp crater may have formed in acidic pH < 4 solutions with ~ 0.1 M Cl- through oxidative dissolution of Fe(II) sulfides and/or oxidizing dissolution of basalts in localized acidic solutions.

The Sample Analysis at Mars (SAM) instrument on the Curiosity rover has detected evidence of oxychlorine compounds (i.e., perchlorates and chlorates) in Gale crater, which has implications for past habitability, diagenesis, aqueous processes, interpretation of in situ organic analyses, understanding the martian chlorine cycle, and hazards and resources for future human exploration. Pure oxychlorines and mixtures of oxychlorines with Mars-analog phases have been analyzed for their oxygen (O ) and hydrogen chloride (HCl) releases on SAM laboratory analog instruments in order to constrain which phases are present in Gale crater. These studies demonstrated that oxychlorines evolve O releases with peaks between ~200 and 600 C, although the thermal decomposition temperatures and the amount of evolved O decrease when iron phases are present in the sample. Mg and Fe oxychlorines decompose into oxides and release HCl between ~200 and 542 C. Ca, Na, and K oxychlorines thermally decompose into chlorides and do not evolve HCl by themselves. However, the chlorides (original or from oxychlorine decomposition) can react with water-evolving phases (e.g., phyllosilicates) in the sample and evolve HCl within the temperature range of SAM (, The research reviewed in this paper was funded by the Mars Science Laboratory (MSL) project office. M.-P.Z. acknowledges funding from the Ministerio de Ciencia e Innovación (ref. PID2019-104205GB-C21).

Changes in weight, feeding rate, and sensitivity of some gustatory receptors have been studied over the course of the last larval instar of Spodoptera exempta. Sucrose, meso-inositol and adenosine were used as the test stimuli on the maxillary sensilla styloconica. Noticeable changes were found only with the response to adenosine, and none of the changes in receptor response were correlated with weight changes, feeding rates, cessation of feeding or transition into the prepupal phase. ZUSAMMENFASSUNG VERANDERUNGEN IN DER FUTTERAUFNAHME UND DER REZEPTOR-EMPFINDLICHKEIT DER LETZTSTADIUM-RAUPE VON SPODOPTERA EXEMPTA Veranderungen im Gewicht, in der Futteraufnahme und in der Empfindlichkeit einiger Geschmacksrezeptoren wurden wahrend des letzten Raupenstadiums von Spodoptera exempta untersucht. Rohrzucker, Meso-Inositol und Adenosin wurden als Testreize fur die Sensilla styloconica der Unterkiefer verwendet. Merkliche Veranderungen wurden nur in der Reaktion auf Adenosin gefunden. Keine der Veranderungen der Rezeptorreaktion war korreliert mit Gewichtsveranderungen, mit Futteraufnahme oder mit dem Ubergang ins Vorpuppenstadium.

Electrophysiological recording with salicin and caffein from mouthpart receptors (labrum, maxillae, labial palpi) of sixth instar Spodoptera exempta (Wlk.) (Noctuidae) indicate the presence of receptors to these compounds in the maxillary sensilla styloconica. Feeding tests have confirmed that inhibition of feeding is produced by these two compounds, and ablation experiments suggest the presence of other, still unlocated, sucrose, salicin and caffein receptors. RESUME ETUDE AVEC LA SALICINE ET LA CAFEINE DES RECEPTEURS DES SUBSTANCES INHIBANT LA PRISE DE NOURRITURE CHEZ LE DERNIER STADE LARVAIRE DE SPODOPTERA EXEMPTA (LEP. NOCTUIDAE). L'enregistrement electrophysiologique des recepteurs des pieces buccales (labre, maxilles, palpes labiaux) des larves du sixieme stade de Spodoptera exempta en presence de salieme et de caffeine, revele l'existence de recepteurs a ces composes sur les sensilles styloconiques maxillaires. Des tests de prise de nourriture ont confirme que l'inhibition de l'alimentation est provoquee par ces deux composes, et des experiences d'ablation suggerent la presence d'autres recepteurs, non encore localises, au sucrose, a la salicine et a la cafeine.

Rhythmic activity, having a period similar to that of the pumping behaviour of the intact barnacle, can be recorded from the isolated ventral ganglion ofBalanus hameri. Evidence is presented for a rhythm generated presynaptically by PSP's which have an excitatory effect on one set of neurones and an inhibitory effect on an out of phase set of neurones. Electric shocks give results suggesting that the rhythm arises through a relaxation oscillator mechanism, and lesion experiments suggest that the rhythm arises in the central region of the ganglion. Deafferentation indicates that the rhythm's generation is entirely endogenous, although it can be affected by sensory input from the cirri.

Anatomical studies on the 6 posterior cirri of the barnacle,Balanus hameri, have revealed the presence of a number of bipolar and multipolar sensory neurons in the coxopodite-basipodite-ramal (CBR) region which appear to function as proprioceptors. The cells are associated with two simple strands which terminate on the surface of the flexor muscles or on the hypodermis.

A 27 year old man had attacks of violence for three years before he died in 1945. Necropsy revealed multiple cavernous angiomata of the brain. This man's daughter died in 1969 at the age of 28 years after a year of intermittent headaches. Necropsy showed a large cavernous angioma in the right temporal lobe. Until now the literature has contained only scanty circumstantial evidence for a familial occurrence of cavernous angiomata of the brain.

We report a case of the brown bowel syndrome presenting as major dilatation of the colon which resembled 'toxic dilatation' and necessitated subtotal colectomy. We confirm the reported association between the brown bowel syndrome, malabsorption, and hypovitaminosis E. Furthermore we document failure of the brown pigmentation to resolve after six months in spite of vitamin E supplements and correction of the malabsorption. Finally we suggest that, although the brown bowel syndrome is rare, it should be considered in cases of major colonic dilatation where the patient is or may be suffering from a malabsorption syndrome, and where the sigmoidoscopic appearances do not suggest severe inflammatory bowel disease.

Summary Two cases of sudden death due to perforation of a benign oesophageal ulcer into a major blood vessel are reported. In one man, anaemia and aspiration pneumonitis dominated the clinical picture. He had an oesophageal stricture and a chronic peptic ulcer associated with an incarcerated hiatus hernia. Death was due to haemorrhage caused by perforation of the ulcer into the thoracic aorta. The second patient presented with confusion and falls, backache and indigestion. She had a hiatus hernia and a large benign chronic oesophageal ulcer. Death was due to perforation of the ulcer into the left pulmonary vein. The cases are presented for their rarity, to illustrate the complex and late presentation of problems in geriatric medicine, and as a reminder that reflux oesophagitis can be dangerous.

Microwave and ultrasonic reflections from a liquid surface have been studied to determine the feasibility of their use in measuring liquid flow. Reflected ultrasonic pulses appear useful for measuring the change between static levels of large dimensions. However, for measuring small continuous changes the accuracy is not satisfactory. Microwave reflections provide an output that can be used for the measurement of total change in level or flow data.