Explore the vast range of titles available.

Helicobacter pylori (Hp) infection in diabetic patients has been related to impaired gastric clearance of bacteria due to autonomic neuropathy. Gastrointestinal dysfunction has been described in primary autonomic failure (AF). The aim of the study was to evaluate, for the first time, the presence of Hp infection and gastric function in patients with primary AF Twelve patients with primary AF (aged 58-78), 31 healthy controls (aged 48-75) and 31 patients affected by type 2 diabetes (aged 46-75) were studied. A 13C-urea breath test was performed to assess the presence of Hp infection. To evaluate gastric function, AF patients underwent two non-invasive tests: 1) 13C-octanoic acid breath test (OBT) to evaluate gastric emptying, and 2) electrogastrogram (EGG) to evaluate gastric electrical activity. Hp infection was found in 100% of AF patients, in 48% of controls and in 71% of diabetic patients (p = 0.02 between groups). Electrical or mechanical gastric function was altered in 50% of AF patients. In particular, 1) after OBT, half-time gastric emptying was delayed in 6 out of 12 patients, and 2) EGG showed the presence of gastric dysrhythmias in 6 out of 12 patients. In conclusion, Hp infection was detected in all AF patients studied; as previously demonstrated in diabetes, such a finding might be related to autonomic neuropathy causing mechanical or electrical gastric dysfunction. Hp detection might be important for the gastrointestinal and extradigestive complications of such infection.

Emissions reduction and greenhouse gas removal from the atmosphere are both necessary to achieve net-zero emissions and limit climate change 1 . There is thus a need for improved sorbents for the capture of carbon dioxide from the atmosphere, a process known as direct air capture. In particular, low-cost materials that can be regenerated at low temperatures would overcome the limitations of current technologies. In this work, we introduce a new class of designer sorbent materials known as ‘charged-sorbents’. These materials are prepared through a battery-like charging process that accumulates ions in the pores of low-cost activated carbons, with the inserted ions then serving as sites for carbon dioxide adsorption. We use our charging process to accumulate reactive hydroxide ions in the pores of a carbon electrode, and find that the resulting sorbent material can rapidly capture carbon dioxide from ambient air by means of (bi)carbonate formation. Unlike traditional bulk carbonates, charged-sorbent regeneration can be achieved at low temperatures (90–100 °C) and the sorbent’s conductive nature permits direct Joule heating regeneration 2 , 3 using renewable electricity. Given their highly tailorable pore environments and low cost, we anticipate that charged-sorbents will find numerous potential applications in chemical separations, catalysis and beyond. Charged-sorbents are a new class of designer sorbent materials for the capture of carbon dioxide from the atmosphere, and can be regenerated at low temperatures with direct heating generation using renewable electricity.

The process of carbon capture and sequestration has been proposed as a method of mitigating the build-up of greenhouse gases in the atmosphere. If implemented, the cost of electricity generated by a fossil fuel-burning power plant would rise substantially, owing to the expense of removing CO 2 from the effluent stream. There is therefore an urgent need for more efficient gas separation technologies, such as those potentially offered by advanced solid adsorbents. Here we show that diamine-appended metal-organic frameworks can behave as ‘phase-change’ adsorbents, with unusual step-shaped CO 2 adsorption isotherms that shift markedly with temperature. Results from spectroscopic, diffraction and computational studies show that the origin of the sharp adsorption step is an unprecedented cooperative process in which, above a metal-dependent threshold pressure, CO 2 molecules insert into metal-amine bonds, inducing a reorganization of the amines into well-ordered chains of ammonium carbamate. As a consequence, large CO 2 separation capacities can be achieved with small temperature swings, and regeneration energies appreciably lower than achievable with state-of-the-art aqueous amine solutions become feasible. The results provide a mechanistic framework for designing highly efficient adsorbents for removing CO 2 from various gas mixtures, and yield insights into the conservation of Mg 2+ within the ribulose-1,5-bisphosphate carboxylase/oxygenase family of enzymes. A cooperative insertion mechanism for CO 2 adsorption is shown to generate highly efficient adsorbents for carbon capture applications. Efficient CO 2 absorption in a metal-organic framework Advanced solid adsorbents are being investigated as potential agents for efficient gas separation technologies that could help make carbon capture technologies more economical. This paper probes the mechanism of carbon dioxide adsorption of a previously reported diamine-appended metal-organic framework. This material demonstrates unusual and potentially practically useful adsorption properties. The authors find that CO 2 adsorbs through insertion into the highly stable metal-amine bonds of the metal-organic framework. As a consequence of the homogenous and perfect spacing of amines, as dictated by the framework's topology, the insertion of a single CO 2 molecule induces neighbouring sites to also adsorb CO 2 in an unprecedented chain reaction process.

Enzymatic haem and non-haem high-valent iron–oxo species are known to activate strong C–H bonds, yet duplicating this reactivity in a synthetic system remains a formidable challenge. Although instability of the terminal iron–oxo moiety is perhaps the foremost obstacle, steric and electronic factors also limit the activity of previously reported mononuclear iron( IV )–oxo compounds. In particular, although nature's non-haem iron( IV )–oxo compounds possess high-spin S  = 2 ground states, this electronic configuration has proved difficult to achieve in a molecular species. These challenges may be mitigated within metal–organic frameworks that feature site-isolated iron centres in a constrained, weak-field ligand environment. Here, we show that the metal–organic framework Fe 2 (dobdc) (dobdc 4−  = 2,5-dioxido-1,4-benzenedicarboxylate) and its magnesium-diluted analogue, Fe 0.1 Mg 1.9 (dobdc), are able to activate the C–H bonds of ethane and convert it into ethanol and acetaldehyde using nitrous oxide as the terminal oxidant. Electronic structure calculations indicate that the active oxidant is likely to be a high-spin S  = 2 iron( IV )–oxo species. Selective functionalization of light hydrocarbons is a challenging but desirable transformation. Now a family of Fe( II )-based metal–organic frameworks has been shown to convert ethane into ethanol and acetaldehyde using N 2 O. Electronic structure calculations indicate that the active Fe oxidant in the MOF is a high-spin S  = 2 iron( II )–oxo species.

The process of carbon capture and sequestration has been proposed as a method of mitigating the build-up of greenhouse gases in the atmosphere. If implemented, the cost of electricity generated by a fossil fuel-burning power plant would rise substantially, owing to the expense of removing C[O.sub.2] from the effluent stream. There is therefore an urgent need for more efficient gas separation technologies, such as those potentially offered by advanced solid adsorbents. Here we show that diamine-appended metal-organic frameworks can behave as 'phase-change' adsorbents, with unusual step-shaped C[O.sub.2] adsorption isotherms that shift markedly with temperature. Results from spectroscopic, diffraction and computational studies show that the origin of the sharp adsorption step is an unprecedented cooperative process in which, above a metal-dependent threshold pressure, C[O.sub.2] molecules insert into metal-amine bonds, inducing a reorganization of the amines into well-ordered chains of ammonium carbamate. As a consequence, large C[O.sub.2] separation capacities can be achieved with small temperature swings, and regeneration energies appreciably lower than achievable with state-of-the-art aqueous amine solutions become feasible. The results provide a mechanistic framework for designing highly efficient adsorbents for removing C[O.sub.2] from various gas mixtures, and yield insights into the conservation of [Mg.sup.2+] within the ribulose-1,5-bisphosphate carboxylase/oxygenase family of enzymes.

Emissions reduction and greenhouse gas removal from the atmosphere are both necessary to achieve net-zero emissions and limit climate change. There is thus a need for improved sorbents for the capture of carbon dioxide from the atmosphere, a process known as direct air capture. In particular, low-cost materials that can be regenerated at low temperatures would overcome the limitations of current technologies. In this work, we introduce a new class of designer sorbent materials known as ‘charged-sorbents’. These materials are prepared through a battery-like charging process that accumulates ions in the pores of low-cost activated carbons, with the inserted ions then serving as sites for carbon dioxide adsorption. We use our charging process to accumulate reactive hydroxide ions in the pores of a carbon electrode, and find that the resulting sorbent material can rapidly capture carbon dioxide from ambient air by means of (bi)carbonate formation. Unlike traditional bulk carbonates, charged-sorbent regeneration can be achieved at low temperatures (90–100 °C) and the sorbent’s conductive nature permits direct Joule heating regeneration using renewable electricity. Given their highly tailorable pore environments and low cost, we anticipate that charged-sorbents will find numerous potential applications in chemical separations, catalysis and beyond.