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Direct air capture (DAC) aims to remove CO2 directly from the atmosphere. In this study, we have demonstrated proof-of-concept of a DAC process combining CO2 adsorption in a packed bed of amine-functionalized anion exchange resins (AERs) with a pH swing regeneration using an electrochemical cell (EC). The resin bed was regenerated using the alkaline solution produced in the cathodic compartment of the EC, while high purity CO2 (>95%) was desorbed in the acidifying compartment. After regenerating the AERs, some alkaline solution remained on the surface of the resins and provided additional CO2 capture capacity during adsorption. The highest CO2 capture capacity measured was 1.76 mmol·g-1 dry resins. Moreover, as the whole process was operated at room temperature, the resins did not show any apparent degradation after 150 cycles of adsorption-desorption. Furthermore, when the relative humidity of the air source increased from 33 to 84%, the water loss of the process decreased by 63%, while CO2 capture capacity fell 22%. Finally, although the pressure drop of the adsorption column (5 ± 1 kPa) and the energy consumption of the EC (537 ± 33 kJ·mol-1 at 20 mA·cm-2) are high, we have discussed the potential improvements toward a successful upscaling.

Objective: Navigated pedicle screw placement holds distinct advantages in spinal oncology. New implant materials such as carbon-fiber reinforced PEEK (CFRP) additionally increase the quality of radiological follow-up and adjuvant radiation therapy planning through the reduction of imaging artifacts [for full text, please go to the a.m. URL]

Objective: Fifty percent of Multiple Myeloma (MM) patients suffer from vertebral column lesions. Indications for spine surgery are made with restraint because of an allegedly high complication rate. Structured data assessing indications, strategies, and optimal timing of spine surgery is lacking. The [for full text, please go to the a.m. URL]

During electrochemical nutrient recovery, current and ion exchange membranes (IEM) are used to extract an ionic species of interest (e.g., ion) from a mixture of multiple ions. The species of interest (ion 1) has an opposing charge to the IEM. When ion 1 is extracted from the solution, the species fractions at the membrane and the adjunct boundary layers are affected. Hence, the species transport through the electrochemical system (ES) can no longer be described as electrodialysis-like. A dynamic state is observed in the compartments, where the ionic species are recovered. When the boundary layer-membrane interface is depleted, the IEM is at maximum current. If the ES is operated at a current higher than the maximum current, the fluxes of both ion 1 and other competing ions, with the same charge (ion 2), occur. This means, for example, ion 1 will be recovered, and the concentration of ion 2 will build up in time. Therefore, a steady state is never reached. Ideally, to prevent the effect of limiting current at the boundary layer-membrane interface, ES for nutrient recovery should be operated at low currents.

The atmospheric carbon dioxide (CO2) concentration has increased by nearly 49% compared to preindustrial levels. This increase is primarily ascribed to anthropogenic activities and has caused rapid climate change in recent years. Direct air capture (DAC) technologies, aiming to remove CO2 directly from the atmosphere, are indispensable for mitigating the climate risks. One of the most studied DAC technologies is wet scrubbing with alkaline hydroxide solutions (e.g., KOH). Recently, we developed an electrochemical system that can regenerate spent alkaline absorbents from DAC and desorb high-purity CO2 gas under atmospheric pressure. The electrochemical cell consisted of three compartments, i.e., an anode compartment, an “acidifying” compartment, and a cathode compartment (Figure 1). During the operation, protons (H+) produced from the H2 oxidation at the anode are transported to the acidifying compartment where the spent absorbent coming from the air contactor is fed. The decreasing pH of the acidifying solution facilitates the conversion of bicarbonate/carbonate ions to carbonic acid (H2CO3 *, including dissolved CO2). When the chemical potential of oversaturated H2CO3 * is higher than the partial pressure of CO2 in the gas phase, CO2 can be desorbed. In the cathode compartment, the K+ from acidifying compartment combines with the locally produced hydroxides (OH−) to regenerate the alkaline absorbent. Overall, the electrochemical cell creates a pH swing in two adjacent compartments. CO2 gas is desorbed at low pH while the alkaline absorbent is regenerated at high pH. In the acidifying compartment, the cations changed from K+ to H+ that can displace the equilibrium of the carbon species towards the desorption of CO2 gas. However, this phenomenon brings two limitations to large-scale application of the system. Firstly, the depleting of K+ and HCO3 -/CO3 2- leads to the decrease of conductivity of the acidifying solution, which induces the increase of ohmic losses in the cell. Moreover, the desorbed CO2 gas bubbles in the cell also contributes to the electrical resistance of the cell. Therefore, the current work investigates optimization strategies to reduce the energy consumption of the system. The first strategy is to desorb CO2 into a lower CO2 partial pressure gas phase instead of atmospheric pressure. A decrease in the CO2 partial pressure from 0.9 to 0.3 bar displayed a maximum increase of 13% in gas production due to higher driving force for desorption and a maximum decrease of 7% in cell potential due to reduced gas bubble presence in the cell. The second strategy adds background electrolyte (phosphate or sulfate) into the absorbent. The adding of background electrolyte provided extra conductivity in the acidifying solution when most of the K+ and CO2 have been removed. Furthermore, the background electrolyte reduced the pH of the acidifying solution, which benefits the desorption of CO2. The lowest specific energy consumption achieved in this study was 249 kJ mol-1 CO2 captured under 150 A m-2. This low energy consumption makes the technology competitive among its counterparts. Finally, an equilibrium model has been developed that simulates the performance of the system and indicates further improvement potentials. This work demonstrates the proof of concept of a novel electrochemical direct air capture process. Our main conclusions show that the process has a competent energy consumption and potential for upscaling with the tested optimization strategies. Figure 1

Objective: Acetazolamide, a carbonic anhydrase inhibitor, is widely used in neurosurgical practice for treatment of hydrocephalus and benign intracranial hypertension. However, its administration in head trauma patients is not recommended due to the vasodilatation properties of acetazolamide: according[for full text, please go to the a.m. URL], 68. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), 7. Joint Meeting mit der Society of British Neurological Surgeons (SBNS)

Objective: In previous experiments the increased brain edema in mice subjected to decompressive craniectomy after closed head injury has been documented 24h after injury. The goal of the current experiment was to analyze whether the problem of exacerbated brain swelling persists over the longer period[for full text, please go to the a.m. URL], 67. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC), 1. Joint Meeting mit der Koreanischen Gesellschaft für Neurochirurgie (KNS)

BACKGROUND: To evaluate postoperative lens opacifications in foldable hydrophilic intraocular lenses. PATIENTS AND METHODS: 12 patients (9 female; 3 male; mean age 77.5 +/- 3 years) were referred from one ophthalmologic surgeon because of opacification of IOLs and markedly decreased visual acuity. Time between implantation and explantation varied from 8 month to 3 years. IOL explantation was performed in all 12 patients and IOL were examined by light-, transmission- and scanning electron microscopy. RESULTS: IOL-explantation was uneventful in all 12 patients. The explanted IOLs showed crystalline deposits 0.5 to 2 microm in diameter immediately beneath the surface of the lens. Eight of 12 patients had elevated serum levels for glucose (6 patients with manifest diabetes mellitus, 2 patients with pathological elevated levels for glucose). CONCLUSIONS: Postoperative opacification of hydrogel foldable lenses (Hydroview(R)) are apperantly caused by formation of crystalline deposits beneath the lens surface. These deposits may be associated with metabolic disorders, e.g. diabetes mellitus.

H(2) can be produced from organic matter with a microbial electrolysis cell (MEC). To decrease MEC capital costs, a cathode is needed that is made of low-cost material and produces H(2) at high rate. A microbial biocathode is a low-cost candidate, but suffers from a long startup and a low H(2) production rate. In this study, the effects of cathode potential and carbon source on microbial biocathode startup were investigated. Application of a more negative cathode potential did not decrease the startup time of the biocathode. If acetate instead of bicarbonate was used as carbon source, the biocathode started up more than two times faster. The faster startup was likely caused by a higher biomass yield for acetate than for bicarbonate, which was supported by thermodynamic calculations. To increase the H(2) production rate, a flow through biocathode fed with acetate was investigated. This biocathode produced 2.2 m(3) H(2) m(-3) reactor day(-1) at a cathode potential of -0.7 V versus NHE, which was seven times that of a parallel flow biocathode of a previous study.

Coiled tubing logging (CTL) or conveying electric logging tools with coiled tubing (CT) was first adopted as a technique during the late 1980s. With this technique, the rigidity of the CT allowed conventional logging tools to be pushed into highly deviated and horizontal wellbores, which were otherwise inaccessible at that time. The advent of wireline tractor technology has since provided an alternative to log some well profiles without employing CT at all. CTL still provides a superior solution for many well types and operations. Some of the advantages of the technique, which make it relevant even today, include the ability to pump while logging, efficacy in openhole environments, and overall robustness of the downhole system. CTL, as a technique, however, comes with some complexities. Operationally, many of these complexities revolve around the logging head adapter, which is the component that connects the logging tools to the CT cable assembly. Over the years, tool designs have evolved to incorporate several feature upgrades, which are aimed at improving overall system performance and reliability. A novel tool design, which addresses the significant downtime associated with building the logging head assembly during CTL operations was recently introduced into service. The rugged system, with its unique injector stab-through feature, can be used during CT-assisted well-logging and wired-perforating operations. Several case histories have demonstrated that the system results in improved overall performance through reduced operating time without compromising tool reliability and function.

This paper, for the first time, describes the development of a microbial biocathode for hydrogen production that is based on a naturally selected mixed culture of electrochemically active micro-organisms. This is achieved through a three-phase biocathode startup procedure that effectively turned an acetate- and hydrogen-oxidizing bioanode into a hydrogen-producing biocathode by reversing the polarity of the electrode. The microbial biocathode that was obtained in this way had a current density of about -1.2 A/Nm2 at a potential of -0.7 V. This was 3.6 times higher than that of a control electrode (-0.3 A/m2). Furthermore, the microbial biocathode produced about 0.63 m3 H2/m3 cathode liquid volume/day at a cathodic hydrogen efficiency of 49% during hydrogen yield tests, whereas the control electrode produced 0.08 m3 H2/m3 cathode liquid volume/day at a cathodic hydrogen efficiency of 25%. The effluent of the biocathode chamber could be used to inoculate another electrochemical cell that subsequently also developed an identical hydrogen-producing biocathode (-1.1 A/m2 at a potential of -0.7 V). Scanning electron micrographs of both microbial biocathodes showed a well-developed biofilm on the electrode surface.