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The capacity to evaluate the outcomes of our actions is fundamental for adapting and optimizing behavior and depends on an action-monitoring system that assesses ongoing actions and detects errors. The neuronal network underlying this executive function, classically attributed to the rostral cingulate zone, is poorly characterized in humans, owing to the limited number of direct neurophysiological data. Using intracerebral recordings, we show that the leading role is played by the supplementary motor area (SMA), which rapidly evaluates successful and erroneous actions. The rostral part of medial prefrontal cortex, driven by the SMA, was activated later and exclusively in the case of errors. This suggests a hierarchical organization of the different frontal regions involved in implementation of action monitoring and error processing.

Abstract BACKGROUND No guidelines have been published regarding stereotactic radiosurgery (SRS) in the management of Spetzler-Martin grade I and II arteriovenous malformations (AVMs). OBJECTIVE To establish SRS practice guidelines for grade I-II AVMs on the basis of a systematic literature review. METHODS Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant search of Medline, Embase, and Scopus, 1986-2018, for publications reporting post-SRS outcomes in ≥10 grade I-II AVMs with a follow-up of ≥24 mo. Primary endpoints were obliteration and hemorrhage; secondary outcomes included Spetzler-Martin parameters, dosimetric variables, and “excellent” outcomes (defined as total obliteration without new post-SRS deficit). RESULTS Of 447 abstracts screened, 8 were included (n = 1, level 2 evidence; n = 7, level 4 evidence), representing 1102 AVMs, of which 836 (76%) were grade II. Obliteration was achieved in 884 (80%) at a median of 37 mo; 66 hemorrhages (6%) occurred during a median follow-up of 68 mo. Total obliteration without hemorrhage was achieved in 78%. Of 836 grade II AVMs, Spetzler-Martin parameters were reported in 680: 377 were eloquent brain and 178 had deep venous drainage, totaling 555/680 (82%) high-risk SRS-treated grade II AVMs. CONCLUSION The literature regarding SRS for grade I-II AVM is low quality, limiting interpretation. Cautiously, we observed that SRS appears to be a safe, effective treatment for grade I-II AVM and may be considered a front-line treatment, particularly for lesions in deep or eloquent locations. Preceding publications may be influenced by selection bias, with favorable AVMs undergoing resection, whereas those at increased risk of complications and nonobliteration are disproportionately referred for SRS.

Microfluidic systems are now being designed with precision as miniaturized fluid manipulation devices that can execute increasingly complex tasks. However, their operation often requires numerous external control devices owing to the typically linear nature of microscale flows, which has hampered the development of integrated control mechanisms. Here we address this difficulty by designing microfluidic networks that exhibit a nonlinear relation between the applied pressure and the flow rate, which can be harnessed to switch the direction of internal flows solely by manipulating the input and/or output pressures. We show that these networks— implemented using rigid polymer channels carrying water—exhibit an experimentally supported fluid analogue of Braess’s paradox, in which closing an intermediate channel results in a higher, rather than lower, total flow rate. The harnessed behaviour is scalable and can be used to implement flow routing with multiple switches. These findings have the potential to advance the development of built-in control mechanisms in microfluidic networks, thereby facilitating the creation of portable systems and enabling novel applications in areas ranging from wearable healthcare technologies to deployable space systems. Microfluidic systems controlled by a single driving pressure are programmed to exhibit complex flow-switching schemes and a fluid analogue of Braess’s paradox by exploiting fluid inertia and network design.

Abstract BACKGROUND Guidelines regarding stereotactic radiosurgery (SRS) for brain metastases are missing recently published evidence. OBJECTIVE To conduct a systematic review and provide an objective summary of publications regarding SRS in managing patients with 1 to 4 brain metastases. METHODS Using Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines, a systematic review was conducted using PubMed and Medline up to November 2016. A separate search was conducted for SRS for larger brain metastases. RESULTS Twenty-seven prospective studies, critical reviews, meta-analyses, and published consensus guidelines were reviewed. Four key points came from these studies. First, there is no detriment to survival by withholding whole brain radiation (WBRT) in the upfront management of brain metastases with SRS. Second, while SRS on its own provides a high rate of local control (LC), WBRT may provide further increase in LC. Next, WBRT does provide distant brain control with less need for salvage therapy. Finally, the addition of WBRT does affect neurocognitive function and quality of life more than SRS alone. For larger brain metastases, surgical resection should be considered, especially when factoring lower LC with single-session radiosurgery. There is emerging data showing good LC and/or decreased toxicity with multisession radiosurgery. CONCLUSION A number of well-conducted prospective and meta-analyses studies demonstrate good LC, without compromising survival, using SRS alone for patients with a limited number of brain metastases. Some also demonstrated less impact on neurocognitive function with SRS alone. Practice guidelines were developed using these data with International Stereotactic Radiosurgery Society consensus.

Stereotactic radiosurgery (SRS) is a standard option for brain metastases (BM). There is lack of consensus when patients have a systemic treatment, if a washout is necessary. The aim of this review is to analyze the toxicity of SRS when it is concurrent with chemotherapies, immunotherapy, and/or targeted therapies. From Medline and Embase databases, we searched for English literature published up to April 2020 according to the PRISMA guidelines, using for key words the list of the main systemic therapies currently in use And “radiosurgery,” “SRS,” “GKRS,” “Gamma Knife,” “toxicity,” “ARE,” “radiation necrosis,” “safety,” “brain metastases.” Studies reporting safety or toxicity with SRS concurrent with systemic treatment for BM were included. Of 852 abstracts recorded, 77 were included. The main cancers were melanoma, lung, breast, and renal carcinoma. These studies cumulate 6384 patients. The median SRS dose prescription was 20 Gy [12–30] .For some, they compared a concurrent arm with a non-concurrent or a SRS-alone arm. There were no skin toxicities, no clearly increased rate of bleeding, or radiation necrosis with significant clinical impact. SRS combined with systemic therapy appears to be safe, allowing the continuation of treatment when brain SRS is considered.

Background. Methanogens are antibiotic-resistant anaerobic archaea that escape routine detection in clinical microbiology. We hypothesized that methanogens are part of the anaerobic community that cause brain abscess. Methods. Methanogens were investigated in 1 index sample using specific polymerase chain reaction (PCR) sequencing and culture. The pathogenesis of a methanogen isolate was assessed in a mouse model. Archaea-specific quantitative (q) PCR and metagenomics were used to detect specific archaeal sequences in brain abscess samples and controls. Results. In 1 index sample, routine culture found Porphyromonas endodontalis and Streptococcus intermedius, and specific culture found Methanobrevibacter oralis susceptible to metronidazole and fusidic acid. Archaea-targeted PCR sequencing and metagenomics confirmed M. oralis along with 14 bacteria, including S. intermedius. Archaea-specific qPCR yielded archaea in 8/18 brain abscess specimens and 1/27 controls (P < .003), and metagenomics yielded archaea, mostly methanogens, in 28/32 brain abscess samples, and no archaea in 71 negative controls (P < 10−6). Infection of mice brains yielded no mortality in 14 controls and death in 17/22 M. oralis-inoculated mice (P < 10−6), 32/95 S. intermedius-inoculated mice (P < 10−6), and 75/104 mice inoculated with M. oralis mixed with S. intermedius (P < 10−6) 7 days post-inoculation. Conclusion. Methanogens belong to the anaerobic community responsible for brain abscess, and M. oralis may participate in the pathogenicity of this deadly infection. In mice, a synergy of M. oralis and S. intermedius was observed. Antibiotic treatment of brain abscess should contain anti-archaeal compounds such as imidazole derivatives in most cases.

The annual yield of bifacial photovoltaic systems is highly dependent on the albedo of the underlying soil. There are currently no published data about the albedo of red soil in western Africa. In this study, the impact of the albedo of red soil in Ghana on the energy yield of bifacial photovoltaic systems is analysed. A bifacial photovoltaic simulation model is created by combining the optical view factor matrix with an electrical output simulation. For an exact simulation, the albedo of red soil at three different locations in Ghana is measured for the first time. The average albedo of every red soil is clearly determined, as well as the measurement span including instrumentation uncertainty; values between 0.175 and 0.335 were measured. Considering these data, a state-of-the-art bifacial photovoltaic system with an average of 19.8% efficient modules in northern Ghana can achieve an annual energy yield of 508.8 kWh/m2 and a bifacial gain of up to 18.3% in comparison with monofacial photovoltaic panels. To summarise, red soil in two out of three locations in Ghana shows higher albedo values than most natural ground surfaces and therefore positively impacts the annual yield of bifacial photovoltaic systems.

Abstract BACKGROUND Radiosurgery is the main alternative to microsurgical resection for benign meningiomas. OBJECTIVE To assess the long-term efficacy and safety of radiosurgery for meningiomas with respect to tumor growth and prevention of associated neurological deterioration. Medium- to long-term outcomes have been widely reported, but no large multicenter series with long-term follow-up have been published. METHODS From 15 participating centers, we performed a retrospective observational analysis of 4565 consecutive patients harboring 5300 benign meningiomas. All were treated with Gamma Knife radiosurgery at least 5 years before assessment for this study. Clinical and imaging data were retrieved from each center and uniformly entered into a database by 1 author (A.S.). RESULTS Median tumor volume was 4.8 cm3, and median dose to tumor margin was 14 Gy. All tumors with imaging follow-up > 24 months were excluded. Detailed results from 3768 meningiomas (71%) were analyzed. Median imaging follow-up was 63 months. The volume of treated tumors decreased in 2187 lesions (58%), remained unchanged in 1300 lesions (34.5%), and increased in 281 lesions (7.5%), giving a control rate of 92.5%. Only 84 (2.2%) enlarging tumors required further treatment. Five- and 10-year progression-free survival rates were 95.2% and 88.6%, respectively. Tumor control was higher for imaging defined tumors vs grade I meningiomas (P > .001), for female vs male patients (P > .001), for sporadic vs multiple meningiomas (P > .001), and for skull base vs convexity tumors (P > .001). Permanent morbidity rate was 6.6% at the last follow-up. CONCLUSION Radiosurgery is a safe and effective method for treating benign meningiomas even in the medium to long term.