Chalcopyrite solar cells achieve efficiencies above 23%. The latest improvements are due to post‐deposition treatments (PDT) with heavy alkalis. This study provides a comprehensive description of the effect of PDT on the chemical and electronic structure of surface and bulk of Cu(In,Ga)Se2. Chemical changes at the surface appear similar, independent of absorber or alkali. However, the effect on the surface electronic structure differs with absorber or type of treatment, although the improvement of the solar cell efficiency is the same. Thus, changes at the surface cannot be the only effect of the PDT treatment. The main effect of PDT with heavy alkalis concerns bulk recombination. The reduction in bulk recombination goes along with a reduced density of electronic tail states. Improvements in open‐circuit voltage appear together with reduced band bending at grain boundaries. Heavy alkalis accumulate at grain boundaries and are not detected in the grains. This behavior is understood by the energetics of the formation of single‐phase Cu‐alkali compounds. Thus, the efficiency improvement with heavy alkali PDT can be attributed to reduced band bending at grain boundaries, which reduces tail states and nonradiative recombination and is caused by accumulation of heavy alkalis at grain boundaries.

This review summarizes the current status of Cu(In,Ga)(S,Se) 2 (CIGS) thin film solar cell technology with a focus on recent advancements and emerging concepts intended for higher efficiency and novel applications. The recent developments and trends of research in laboratories and industrial achievements communicated within the last years are reviewed, and the major developments linked to alkali post deposition treatment and composition grading in CIGS, surface passivation, buffer, and transparent contact layers are emphasized. Encouraging results have been achieved for CIGS-based tandem solar cells and for improvement in low light device performance. Challenges of technology transfer of lab's record high efficiency cells to average industrial production are obvious from the reported efficiency values. One section is dedicated to development and opportunities offered by flexible and lightweight CIGS modules.

Flexible, lightweight Cu(In,Ga)Se2 (CIGS) solar cells grown on polymer substrates are a promising technology with fast growing market prospects. However, power conversion efficiencies of solar cells grown at low temperatures (≈450 °C) remain below the efficiencies of cells grown at high temperature on glass substrates. This contribution discusses the impact on cell efficiency of process improvements of low‐temperature CIGS deposition on flexible polyimide and glass substrates. Different strategies for incorporation of alkali elements into CIGS are evaluated based on a large number of depositions. Postdeposition treatment with heavy alkali (here RbF) enables a thickness reduction of the CdS buffer layer and increases the open‐circuit voltage. Na supply during 3rd stage CIGS deposition positively impacts the cell performance. Coevaporation of heavy alkali (e.g., RbF) during capping layer deposition mitigates the adverse shunting associated with high Cu contents, yielding highest efficiencies with near‐stoichiometric absorber compositions. Furthermore, optimization of the deposition sequence results in absorbers with a 1 µm wide notch region with nearly constant bandgap minimum. The improved processes result in a record cell efficiency of 20.8% for CIGS on flexible substrate.

Objective: In this study, we seek to analyze the determinants of the intracranial electroencephalography seizure onset pattern (SOP) and the impact of the SOP in predicting postsurgical seizure outcome. Methods: To this end, we analyzed 820 seizures from 252 consecutive patients explored by stereo-electroencephalography (total of 2148 electrodes), including various forms of focal refractory epilepsies. We used a reproducible method combining visual and time-frequency analyses. Results: We described eight SOPs: low-voltage fast activity (LVFA), preictal spiking followed by LVFA, burst of polyspikes followed by LVFA, slow wave/ DC shift followed by LVFA, sharp theta/alpha waves, beta sharp waves, rhythmic spikes/spike-waves, and delta-brush. LVFA occurred in 79% of patients. The seizure onset pattern was significantly associated with (1) underlying etiology (burst of polyspikes followed by LVFA with the presence of a focal cortical dysplasia, LVFA with malformation of cortical development, postvascular and undetermined epilepsies), (2) spatial organization of the epileptogenic zone (EZ; burst of polyspikes followed by LVFA with focal organization, slow wave/DC shift followed by LVFA with network organization), and (3) postsurgical seizure outcome (better outcome when LVFA present). Significance: This study demonstrates that the main determinants of the SOP are the underlying etiology and the spatial organization of the EZ. Concerning the postsurgical seizure outcome, the main determinant factor is the spatial organization of the EZ, but the SOP plays also a role, conferring better prognosis when LVFA is present. K E Y W O R D S epilepsy, epilepsy surgery, epileptogenic zone, focal drug-resistant epilepsy, SEEG, seizure onset | 85 SUPPORTING INFORMATION Additional supporting information may be found online in the Supporting Information section at the end of the article. How to cite this article: Lagarde S, Buzori S, Trebuchon A, et al. The repertoire of seizure onset patterns in human focal epilepsies: Determinants and prognostic values. Epilepsia. 2019;60:85-95.

Drug-refractory focal epilepsies are network diseases associated with functional connectivity alterations both during ictal and interictal periods. A large majority of studies on the interictal/resting state have focused on functional MRI-based functional connectivity. Few studies have used electrophysiology, despite its high temporal capacities. In particular, stereotactic-EEG is highly suitable to study functional connectivity because it permits direct intracranial electrophysiological recordings with relative large-scale sampling. Most previous studies in stereotactic-EEG have been directed towards temporal lobe epilepsy, which does not represent the whole spectrum of drug-refractory epilepsies. The present study aims at filling this gap, investigating interictal functional connectivity alterations behind cortical epileptic organization and its association with post-surgical prognosis. To this purpose, we studied a large cohort of 59 patients with malformation of cortical development explored by stereotactic-EEG with a wide spatial sampling (76 distinct brain areas were recorded, median of 13.2 per patient). We computed functional connectivity using non-linear correlation. We focused on three zones defined by stereotactic-EEG ictal activity: the epileptogenic zone, the propagation zone and the non-involved zone. First, we compared within-zone and between-zones functional connectivity. Second, we analysed the directionality of functional connectivity between these zones. Third, we measured the associations between functional connectivity measures and clinical variables, especially post-surgical prognosis. Our study confirms that functional connectivity differs according to the zone under investigation. We found: (i) a gradual decrease of the within-zone functional connectivity with higher values for epileptogenic zone and propagation zone, and lower for non-involved zones; (ii) preferential coupling between structures of the epileptogenic zone; (iii) preferential coupling between epileptogenic zone and propagation zone; and (iv) poorer post-surgical outcome in patients with higher functional connectivity of non-involved zone (within- non-involved zone, between non-involved zone and propagation zone functional connectivity). Our work suggests that, even during the interictal state, functional connectivity is reinforced within epileptic cortices (epileptogenic zone and propagation zone) with a gradual organization. Moreover, larger functional connectivity alterations, suggesting more diffuse disease, are associated with poorer post-surgical prognosis. This is consistent with computational studies suggesting that connectivity is crucial in order to model the spatiotemporal dynamics of seizures.10.1093/brain/awy214_video1awy214media15833456182001.

The hippocampus and amygdala are key brain structures of the medial temporal lobe, involved in cognitive and emotional processes as well as pathological states such as epilepsy. Despite their importance, it is still unclear whether their  neural activity can be recorded non-invasively. Here, using simultaneous intracerebral and magnetoencephalography (MEG) recordings in patients with focal drug-resistant epilepsy, we demonstrate a direct contribution of amygdala and hippocampal activity to surface MEG recordings. In particular, a method of blind source separation, independent component analysis, enabled activity arising from large neocortical networks to be disentangled from that of deeper structures, whose amplitude at the surface was small but significant. This finding is highly relevant for our understanding of hippocampal and amygdala brain activity as it implies that their activity could potentially be measured non-invasively.

Object The roles of the wait-and-see strategy and proactive Gamma Knife surgery (GKS) in the treatment paradigm for small intracanalicular vestibular schwannomas (VSs) is still a matter of debate, especially when patients present with functional hearing. The authors compare these 2 methods. Methods Forty-seven patients (22 men and 25 women) harboring an intracanalicular VS were followed prospectively. The mean age of the patients at the time of inclusion was 54.4 years (range 20–71 years). The mean follow-up period was 43.8 ± 40 months (range 9–222 months). Failure was defined as significant tumor growth and/or hearing deterioration that required microsurgical or radiosurgical treatment. This population was compared with a control group of 34 patients harboring a unilateral intracanalicular VS who were consecutively treated by GKS and had functional hearing at the time of radiosurgery. Results Of the 47 patients in the wait-and-see group, treatment failure (tumor growth requiring treatment) was observed in 35 patients (74%), although conservative treatment is still ongoing for 12 patients. Treatment failure in the control (GKS) group occurred in only 1 (3%) of 34 patients. In the wait-and-see group, there was no change in tumor size in 10 patients (21%), tumor growth in 36 patients (77%), and a mild decrease in tumor size in 1 patient (2%). Forty patients in the wait-and-see group were available for a hearing level study, which demonstrated no change in Gardner-Robertson hearing class for 24 patients (60%). Fifteen patients (38%) experienced more than 10 db of hearing loss and 2 of them became deaf. At 3, 4, and 5 years, the useful hearing preservation rates were 75%, 52%, and 41% in the wait-and-see group and 77%, 70%, and 64% in the control group, respectively. Thus, the chances of maintaining functional hearing and avoiding further intervention were much higher in cases treated by GKS (79% and 60% at 2 and 5 years, respectively) than in cases managed by the wait-and-see strategy (43% and 14% at 2 and 5 years, respectively). Conclusions These data indicate that the wait-and-see policy exposes the patient to elevated risks of tumor growth and degradation of hearing. Both events may occur independently in the mid-term period. This information must be presented to the patient. A careful sequential follow-up may be adopted when the wait-and-see strategy is chosen, but proactive GKS is recommended when hearing is still useful at the time of diagnosis. This recommendation may be a main paradigm shift in the practice of treating intracanalicular VSs.

OBJectiVe Gamma Knife surgery (GKS) is one of the surgical alternatives for the treatment of drug-resistant trigeminal neuralgia (TN). This study aims to evaluate the safety and efficacy of GKS in a large population of patients with TN with very long-term clinical follow-up. methOdS Between July 1992 and November 2010, 737 patients presenting with TN were treated using GKS. Data were collected prospectively and were further retrospectively evaluated at Timone University Hospital. The frequency and severity of pain, as well as trigeminal nerve function, were evaluated before GKS and regularly thereafter. Radiosurgery using the Gamma Knife (model B, C, 4C, or Perfexion) was performed with the help of both MR and CT targeting. A single 4-mm isocenter was positioned in the cisternal portion of the trigeminal nerve at a median distance of 7.6 mm (range 4-14 mm) anterior to the emergence of the nerve (retrogasserian target). A median maximum dose of 85 Gy (range 70-90 Gy) was prescribed. reSultS The safety and efficacy are reported for 497 patients with medically refractory classical TN who were never previously treated by GKS and had a follow-up of at least 1 year. The median age in this series was 68.3 years (range 28.1-93.2 years). The median follow-up period was 43.8 months (range 12-174.4 months). Overall, 456 patients (91.75%) were initially pain free in a median time of 10 days (range 1-180 days). Their actuarial probabilities of remaining pain free without medication at 3, 5, 7, and 10 years were 71.8%, 64.9%, 59.7%, and 45.3%, respectively. One hundred fifty-seven patients (34.4%) who were initially pain free experienced at least 1 recurrence, with a median delay of onset of 24 months (range 0.6-150.1 months). However, the actuarial rate of maintaining pain relief without further surgery was 67.8% at 10 years. The hypesthesia actuarial rate at 5 years was 20.4% and at 7 years reached 21.1%, but remained stable until 14 years with a median delay of onset of 12 months (range 1-65 months). Very bothersome facial hypesthesia was reported in only 3 patients (0.6%). cONcluSiONS Retrogasserian GKS proved to be safe and effective in the long term and in a very large number of patients. Even if the probability of long-lasting effects may be modest compared with microvascular decompression, the rarity of complications prompts discussion of using GKS as the pragmatic surgical first- or second-intention alternative for classical TN. However, a randomized trial, or at least a case-matched control study, would be required to compare with microvascular decompression.http://thejns.org/doi/abs/10.3171/2015.2.JNS142144