Hemodynamics and arrhythmia disorder caused by lithium poisoning: A case report. / 锂中毒导致心律失常、血流动力学障碍1例.

Bipolar affective disorder refers to a category of mood disorders characterized clinically by the presence of both manic or hypomanic episodes and depressive episodes. Lithium stands out as the primary pharmacological intervention for managing bipolar affective disorder. However, its therapeutic dosage closely approaches toxic levels. Toxic symptoms appear when the blood lithium concentration surpasses 1.4 mmol/L, typically giving rise to gastrointestinal and central nervous system reactions. Cardiac toxicity is rare but serious in cases of lithium poisoning. The study reports a case of a patient with bipolar affective disorder who reached a blood lithium concentration of 6.08 mmol/L after the patient took lithium carbonate sustained-release tablets beyond the prescribed dosage daily and concurrently using other mood stabilizers. This resulted in symptoms such as arrhythmia, shock, impaired consciousness, and coarse tremors. Following symptomatic supportive treatment, including blood dialysis, the patient's physical symptoms gradually improved. It is necessary for clinicians to strengthen the prevention and recognition of lithium poisoning.

Case Report on High Dose Lithium Treatment for Post-COVID Depression, Recurrent Fevers, and Skin Lesions.

This is a case of a 35-year-old woman who presented with an 18-month history of post (long)-COVID depression and exhaustion along with recurrent fevers and treatment-resistant skin boils, all of which abated with lithium treatment at a serum level of 1.14 mmol/L, and all of which worsened when the lithium serum level was lowered to 0.8. This paper illustrates Lithium's effectiveness in the treatment of post (long)-COVID syndrome, though a higher serum concentration may be required.

[Determination of trace anions in battery-grade lithium carbonate by double-inhibition on-line matrix-removal ion chromatography].

A method was developed for the determination of trace anions in battery-grade lithium carbonate. In this method, lithium carbonate was dissolved in ultrapure water with ultrasound assistance, and its matrix was removed using an on-line matrix-removal method. In the matrix-removal process, the sample was first passed through an ADRS600(4 mm) suppressor (suppressor current, 150 mA; external water flow rate, 2 mL/min). Hydrogen and lithium ions were then completely exchanged via the ion-exchange membrane in the suppressor, converting the lithium carbonate into carbonic acid. The carbonic acid entered the waste-liquid channel in the form of carbon dioxide through a CRD 200(4 mm) carbonate removal device to remove the lithium carbonate matrix. Finally, the target anions were automatically enriched on an IonPac UTAC-LP2 concentration column (35 mm×3 mm) and automatically transferred to a chromatographic system using valve-switching technology. The chromatographic system featured an IonPac AG18 column (50 mm×2 mm) as the protection column and an IonPac AS18 column (250 mm×2 mm) as the analytical column. The column temperature was 30 ℃, gradient elution was performed using KOH solution as the eluent, and the pump flow rate was 0.30 mL/min. An ADRS600(2 mm) suppressor, suppressor current of 25 mA, injection volume of 250 µL, and conductance detector were also used. The results showed good linear relationships (r≥ 0.999) for F-, Cl-, [Formula: see text] in their respective concentration ranges. The limits of detection (LODs) and quantification (LOQs) were 0.05-0.88 and 0.15-2.92 µg/L, respectively. Lithium carbonate samples were tested six consecutive times, and the relative standard deviations (RSDs) of the peak areas of each ion were less than 0.73%. The same lithium carbonate samples were injected after 0, 2, 4, 8, 12, 18, and 24 h, and the RSD of the peak areas of each ion was less than 0.96%. The average recoveries ranged from 93.3% to 99.3%, and the RSDs (n=6) of samples spiked at three levels were in the range of 0.97%-3.45%. The proposed method has a low method limit of quantification of only 0.5 mg/kg for each ion analyzed and is capable of the simultaneous analysis of multiple ions. Thus, it is suitable for the detection of trace anions in battery-grade lithium carbonate.

Chronic Lithium Intoxication: A Challenging Diagnosis.

Lithium has been used in clinical practice since the 1970s. This medication is commonly used to treat and prevent bipolar disorder, but it has a narrow therapeutic index, making toxicity a frequent occurrence. Chronic lithium intoxication can arise due to progressive accumulation, particularly in contexts of dehydration. The effects of chronic lithium intoxication on the nervous, renal, and cardiac systems, as well as on the thyroid and parathyroid glands, are well documented in the literature. The authors present the case of a 66-year-old woman with schizoaffective psychosis and chronic kidney disease, admitted due to altered mental status and dysarthria. Notwithstanding an earlier clinical recommendation to cease lithium administration more than a year ago, the patient continued its usage, culminating in neurological, cardiac, renal, and endocrine manifestations. Although the diagnosis was delayed, her clinical progression was favorable, obviating the need for renal replacement therapy. This case highlights the importance of a detailed medical history and the diagnostic challenges in clinical practice. The use of this drug without proper monitoring can lead to multisystem dysfunction.

Rich-Carbonyl Carbon Catalysis Facilitating the Li2 CO3 Decomposition for Cathode Lithium Compensation Agent.

The active lithium loss of lithium-ion batteries can be well addressed by adding a cathode lithium compensation agent. Due to the poor conductivity and electrochemical activity, lithium carbonate (Li2 CO3 ) is not considered as a candidate. Herein, an effective cathode lithium compensation agent, the recrystallized Li2 CO3 combined with large specific surface area disordered porous carbon (R-LCO@SPC) is prepared. The screened SPC makes it easier for nano-sized Li2 CO3 to adsorb and decompose on carbon substrate, meantime, exposing plenty of catalytic active sites of C═O, which can significantly improve the electrochemical activity and conductivity of Li2 CO3 , thus greatly reducing the decomposition potential of Li2 CO3 (4.0 V) and releasing high irreversible capacity (580 mAh g-1 ) compared to the unmodified Li2 CO3 (nearly no capacity above 4.6 V). Meantime, the Li2 CO3 can disappear completely without any by-product after the initial cycle accompanied by partially dissolved in electrolyte, optimizing the composition of SEI. The resultant lithium compensation agent applied to LMFP//graphite full cell exhibits a 19.1% increase in energy density, enhancing the rate and cycling performance, demonstrating great practical applications potential in high energy density lithium-ion batteries.

Amorphization of Inorganic Solid Electrolyte Interphase Components and Its Impact on Enhancing Their Transport and Mechanical Properties.

The safety and cycle life of lithium-ion batteries (LIBs) are largely determined by the solid electrolyte interphase (SEI) formed on the surface of the anode. However, there is still a lack of understanding regarding the structure and properties of the individual SEI components. Among others, lithium oxide (Li2O), lithium carbonate (Li2CO3), and lithium fluoride (LiF) are known to be the main components of the inorganic SEI layer in conventional LIBs, but their intrinsic protective roles remain controversial. Herein, we present the transformational effects of their amorphous phase on the mechanical and transport characteristics, based on first-principles calculations. Our studies clearly demonstrate that their amorphous phases exhibit significantly improved Li-ion conductivity when compared to the crystalline structures. Additionally, among them, amorphous LiF emerges as a frontrunner for fast Li+ ion transportation, reversing the conventionally understood hierarchy. Under ambient conditions, the amorphous phases of LiF, Li2O, and Li2CO3 are thermodynamically unstable and tend to undergo recrystallization. However, this work highlights that exceptionally ductile and resilient amorphous phases can form if SEI formation and growth would involve some admixing of lithiophilic impurities like nitrogen (N) within the host matrices.

Study on Early Hydration Mechanism of Double-Liquid Grouting Material Modified by Composite Early Strength Agent.

To achieve an adjustable setting time and significantly improved early strength of a new type of sulphoaluminate cement-based double-liquid grouting material (SACDL), the effects of calcium formate, sodium sulfate, lithium carbonate, and a composite early strength agent on the setting hardening and early hydration behavior of SACDL paste were studied by means of setting time, fluidity, compressive strength, and viscosity tests. The results showed that the adsorption and osmosis of calcium formate, the complex decomposition of sodium sulfate, the precipitation polarization of lithium carbonate and the synergistic action of the composite early strength agent could accelerate the early hydration rate of SACDL, shorten the coagulation time, and improve the early strength of SACDL. The composite effect of 0.8% calcium formate and 0.5% sodium sulfate is the most significant in promoting coagulation and early strength; the initial setting time and final setting time of the slurry were shortened to 5 min and 10 min, respectively; and the 3 h compressive strength was capable of reaching 16.7 MPa, 31% higher than that of the blank group. In addition, X-ray diffraction and SEM morphology observation were used to study the composition of the hydration products and the evolution of the microstructure, which revealed the early hydration mechanism of SACDL under the synergistic effect of the composite early strength agent: (1) The solubility of tricalcium aluminate (C3A) and dihydrate gypsum (CaSO4·2H2O) increased under the low content composite early strength agent condition, which increased the ettringite (AFt) formation rate. HCOO- was able to penetrate the hydration layers of tricalcium silicate (C3S) and dicalcium silicate (C2S), accelerating the dissolution of C3S and C2S and promoting the early hydration of SACDL. (2) Under the condition of a high dosage of the composite early strength agent, the further increase in Ca2+ concentration promoted the crystallization nodules and precipitation of CH and accelerated the formation of calcium silicate hydrate (C-S-H) gel. C-S-H was filled between a large number of rod-like AFt crystals, thus making the structure more dense.

Multi-trial, aggregated, individual participant data mega-analysis of short-term antidepressant versus mood stabilizer monotherapy of bipolar type II major depressive episode.

BACKGROUND: Few studies have systematically examined the safety and effectiveness of antidepressant versus mood stabilizer monotherapy of bipolar II depression. To date, there are no aggregated or mega-analyses of prospective trials of individual participant-level data (IPD) to inform future treatment guidelines on the relative safety and effectiveness of antidepressant or lithium monotherapy. METHODS: Data from a series of four independent, similarly designed trials of antidepressant or lithium monotherapy (where longitudinal IPD were available) (n = 393) were aggregated into an IPD dataset (i.e., mega-analysis). Hierarchical log-linear growth models were used to analyze primary outcome of change over time in Hamilton Rating Scale for Depression (HRSD) scores; while secondary outcomes examined Clinical Global Impressions severity (CGI/S) and change (CGI/C) scores, and change over time in Young Mania Rating (YMR) scores. RESULTS: Relative to lithium monotherapy, antidepressant monotherapy demonstrated significantly greater symptom reduction on HRSD scores across time (b = -2.33, t = -6.68, p < 0.0001), significantly greater symptom reduction on the CGI/S across time (b = -0.414, t = -6.32, p < 0.001), and a significant improvement in CGI/C across time (b = -0.47, t = -7.43, p < 0.0001). No differences were observed in change over time for YMR scores between antidepressant and lithium monotherapy (b = 0.06, t = 0.49, p = 0.62). CONCLUSION: Findings from this IPD mega-analysis of bipolar II depression trials suggest a divergence from current evidence-based guidelines recommending combined mood stabilizer plus antidepressant therapy. The current mega-analysis suggests that antidepressant monotherapy may provide superior short-term effectiveness without clinically meaningful increase in treatment-emergent hypomanic symptoms compared to lithium monotherapy.

Electrolyte-Impregnated Mesoporous Hollow Microreactor to Supplement an Inner Reaction Pathway for Boosting the Cyclability of Li-CO2 Batteries.

Li-CO2 batteries that integrate energy storage with greenhouse gas fixation have received a great deal of attention in the pursuit of carbon neutrality. However, cyclic accumulation of the insulative and insoluble Li2CO3 on the cathode surface severely restrains the battery cyclability, especially under a high depth of discharge/charge. Herein, we design and fabricate a microreactor-type catalyst by embedding Ru nanoparticles into the shells of mesoporous hollow carbon spheres. We show that both the hollow cavity and mesoporous shell are indispensable for concertedly furnishing a high activity to catalyze reversible Li2CO3 formation/decomposition. This unique structure ensures that the Ru sites masked by exterior Li2CO3 deposits during charging can resume the redox process of discharge by working with the prestored electrolyte to establish an inner reaction path. The thus fabricated Li-CO2 batteries demonstrate remarkable cyclability of 1085 cycles under 0.5 Ah g-1 and 326 cycles under 2 Ah g-1 at 1 A g-1, outshining most of the literature reports. This study highlights a smart catalyst design to boost the reversibility and cyclability of Li-CO2 batteries through an "in & out" strategy.

Lithium-Associated Generalized Ostraceous Psoriasis Treated with Adalimumab: A Case Report.

Ostraceous psoriasis is a rare variant of psoriasis, characterized by severe hyperkeratotic lesions resembling an oyster shell. Adalimumab is a biological agent that antagonizes tumor necrosis factor (TNF) and is used clinically in plaque psoriasis. Some medications such as lithium carbonate (LC) may aggravate or trigger psoriasis. Here, we describe a case of generalized ostraceous psoriasis associated with lithium carbonate, whose lesions completely improved after discontinuing lithium carbonate and using adalimumab.

Valproate and lithium: Old drugs for new pharmacological approaches in brain tumors?

Beyond its use as an antiepileptic drug, over time valproate has been increasingly used for several other therapeutic applications. Among these, the antineoplastic effects of valproate have been assessed in several in vitro and in vivo preclinical studies, suggesting that this agent significantly inhibits cancer cell proliferation by modulating multiple signaling pathways. During the last years various clinical trials have tried to find out if valproate co-administration could enhance the antineoplastic activity of chemotherapy in glioblastoma patients and in patients suffering from brain metastases, demonstrating that the inclusion of valproate in the therapeutic schedule causes an improved median overall survival in some studies, but not in others. Thus, the effects of the use of concomitant valproate in brain cancer patients are still controversial. Similarly, lithium has been tested as an anticancer drug in several preclinical studies mainly using the unregistered formulation of lithium chloride salts. Although, there are no data showing that the anticancer effects of lithium chloride are superimposable to the registered lithium carbonate, this formulation has shown preclinical activity in glioblastoma and hepatocellular cancers. However, few but interesting clinical trials have been performed with lithium carbonate on a very small number of cancer patients. Based on published data, valproate could represent a potential complementary therapeutic approach to enhance the anticancer activity of brain cancer standard chemotherapy. Same advantageous characteristics are less convincing for lithium carbonate. Therefore, the planning of specific phase III studies is necessary to validate the repositioning of these drugs in present and future oncological research.

Study of Lithium Biodistribution and Nephrotoxicity in Skin Melanoma Mice Model: The First Step towards Implementing Lithium Neutron Capture Therapy.

Boron neutron capture therapy (BNCT) is one of the promising treatment methods for malignant melanoma. The main issue of this technology is the insufficient selectivity of 10B accumulation in tumor cells. As a result of the neutron absorption by boron, an 84% energy release occurred within the cell by the nuclear reaction 10B (n, α)7Li, which lead to tumor cell death. The use of lithium instead of boron brings a new unique opportunity-local 100% energy release-since all products of the 6Li (n, α)3H reaction have high linear energy transfer characteristics. The aim of this study was to determine the concentrations of Li in the tumor, skin, blood, brain and kidney in experimental animals with B16 melanoma and to analyze the potential Li toxicity after lithium carbonate administration at single doses of 300 and 400 mg/kg. Lithium carbonate was chosen since there is a long-term experience of its use in clinical practice for the treatment of psychiatric disorders. The inductively coupled plasma atomic emission spectrometry was used to evaluate Li concentrations in tissue samples. The accumulation efficiency of Li in the tumor was the highest at a time point of 30 min (22.4 µg/g; at a dose of 400 mg/kg). Despite the high lithium accumulation in the kidneys, the pathological changes in kidney tissues were not found. Thus, lithium may actually be used for the Li-NCT development and future studies can be conducted using 6Li and following irradiation of tumor cells using the schemes of lithium administration tested in this work.

"Addressing the core trait of bipolar disorder": A concept analysis of mood-stabilizing drugs.

OBJECTIVE: The term "mood stabilizer" is controversial in the literature and criticized for being imprecise and overly inclusive, having its retirement suggested to avoid misuse. Nevertheless, it continues to be employed as it may still carry important meaning. METHODS: We employed document analysis for reviewing relevant definitions of mood stabilizer employed in the literature. Then, we clarify the meanings associated with the term by employing evolutionary concept analysis. Based on its results, we present a theoretical model for a mood stabilizer and further match it with evidence gathered from published meta-analyses and other sources for drugs used in the treatment of bipolar disorder. RESULTS: Concept analysis unearthed four attributes of a mood stabilizer that were nested into the following ascending hierarchy: "not worsening," "acute effects," "prophylactic effects," and "advanced effects." "Prophylactic effects" were often considered the core aspect of a legitimate mood stabilizer. CONCLUSION: The proposed model uses a hierarchy of attributes that take into account the complexity of the term and help to determine whether a drug is a mood stabilizer. Prophylaxis is pivotal to the concept, whose utility lies in implying a drug able to truly treat bipolar disorder, as opposed to merely targeting symptoms. Consistent use of the term could encourage investigation of drugs that modify long-term outcomes and illness trajectory, instead of simply approaching symptom clusters.

Insights into Chronic Lithium Toxicity - A Case Report.

BACKGROUND: Bipolar disorder is a chronic psychological disorder, and lithium remains the mainstay of therapy. Lithium toxicity can be acute or chronic and the effects may be disabling or life-threatening. The presence of risk factors can increase the chances of lithium toxicity in a patient on long-term lithium therapy. We hereby report a case of chronic lithium toxicity in a patient with a known case of bipolar disorder. CASE PRESENTATION: A 44-year-old female patient with a known case of bipolar disorder presented with altered sensorium, seizures, and renal insufficiency. On admission, the patient was severely dehydrated and the serum lithium level was 3.43 mEq/L. Hemodialysis was performed and she improved gradually. CONCLUSION: Lithium has constantly proven to be beneficial in lowering suicide rates in bipolar disorder patients over the years since its approval. However, its use is limited due to the risk of toxicity. The chances of developing toxicity are higher in patients on long-term lithium therapy. Patients with high risk factors for toxicity should be monitored frequently as the effects of lithium toxicity can be fatal.

Stainless Steel-Like Passivation Inspires Persistent Silicon Anodes for Lithium-Ion Batteries.

Passivation of stainless steel by additives forming mass-transport blocking layers is widely practiced, where Cr element is added into bulk Fe-C forming the Cr2 O3 -rich protective layer. Here we extend the long-practiced passivation concept to Si anodes for lithium-ion batteries, incorporating the passivator of LiF/Li2 CO3 into bulk Si. The passivation mechanism is studied by various ex situ characterizations, redox peak contour maps, thickness evolution tests, and finite element simulations. The results demonstrate that the passivation can enhance the (de)lithiation of Li-Si alloys, induce the formation of F-rich solid electrolyte interphase, stabilize the Si/LiF/Li2 CO3 composite, and mitigate the volume change of Si anodes upon cycling. The 3D passivated Si anode can fully retain a high capacity of 3701 mAh g-1 after 1500 cycles and tolerate high rates up to 50C. This work provides insight into how to construct durable Si anodes through effective passivation.

Lithium carbonate in amyotrophic lateral sclerosis patients homozygous for the C-allele at SNP rs12608932 in UNC13A: protocol for a confirmatory, randomized, group-sequential, event-driven, double-blind, placebo-controlled trial.

BACKGROUND: Given the large genetic heterogeneity in amyotrophic lateral sclerosis (ALS), it seems likely that genetic subgroups may benefit differently from treatment. An exploratory meta-analysis identified that patients homozygous for the C-allele at SNP rs12608932, a single nucleotide polymorphism in the gene UNC13A, had a statistically significant survival benefit when treated with lithium carbonate. We aim to confirm the efficacy of lithium carbonate on the time to death or respiratory insufficiency in patients with ALS homozygous for the C-allele at SNP rs12608932 in UNC13A. METHODS: A randomized, group-sequential, event-driven, double-blind, placebo-controlled trial will be conducted in 15 sites across Europe and Australia. Patients will be genotyped for UNC13A; those homozygous for the C-allele at SNP rs12608932 will be eligible. Patients must have a diagnosis of ALS according to the revised El Escorial criteria, and a TRICALS risk-profile score between -6.0 and -2.0. An expected number of 1200 patients will be screened in order to enroll a target sample size of 171 patients. Patients will be randomly allocated in a 2:1 ratio to lithium carbonate or matching placebo, and treated for a maximum duration of 24 months. The primary endpoint is the time to death or respiratory insufficiency, whichever occurs first. Key secondary endpoints include functional decline, respiratory function, quality of life, tolerability, and safety. An interim analysis for futility and efficacy will be conducted after the occurrence of 41 events. DISCUSSION: Lithium carbonate has been proven to be safe and well-tolerated in patients with ALS. Given the favorable safety profile, the potential benefits are considered to outweigh the burden and risks associated with study participation. This study may provide conclusive evidence about the life-prolonging potential of lithium carbonate in a genetic ALS subgroup. TRIAL REGISTRATION: EudraCT number 2020-000579-19 . Registered on 29 March 2021.

Titration Mass Spectroscopy (TMS): A Quantitative Analytical Technology for Rechargeable Batteries.

Development of high-energy-density rechargeable battery systems not only needs advanced qualitative characterizations for mechanism exploration but also requires accurate quantification technology to quantitatively elucidate products and fairly assess numerous modification strategies. Herein, as a reliable quantification technology, titration mass spectroscopy (TMS) is developed to accurately quantify O-related anionic redox reactions (Li-O2 battery and nickel-cobalt-manganese (NCM)/Li-rich cathodes), parasitic carbonate deposition and decomposition (derived from air-exposure degradation and electrolyte oxidation), and dead Li0 formation (Li-metal battery and over-discharged graphite anode). TMS technology can harvest key information on products (e.g., quantification of oxidized lattice oxygen and solid electrolyte interphase (SEI)/cathode electrolyte interphase (CEI) components) and guide corresponding design strategy by enhancing understanding of the mechanism (e.g., clearly distinguish the catalytic target of highly oxidative Ni4+ on the NCM cathode). Not limited as a rigid quantification tool for widely known products/mechanisms, TMS technology has been demonstrated as a powerful and versatile tool for the investigations of advanced batteries.

Later onset of Childhood Disintegrative Disorder (CDD): a case report.

Childhood Disintegrative Disorder (CDD) is a rare condition characterized by regression of developmental and behavioral functioning after a period of apparently normal development, with an age of onset around 4 years. CDD is not included within the latest edition of the Diagnostic and Statistical Manual of Mental Disorders. We present a case report of an 11-year-old male who achieved normal development for up to 7 years followed by a deterioration of previously acquired linguistic, intellectual, and social skills. Following treatment with lithium carbonate combined with risperidone, the patient experienced a reduction in irritability and aggression. CDD is a rare condition; therefore, the data presented may be useful to investigate its characteristics of the onset, to improve the understanding of the aspects of differentiation from the Autism Spectrum Disorder and finally to propose the possibility of treatment.

Carbonate-superstructured solid fuel cells with hydrocarbon fuels.

A basic requirement for solid oxide fuel cells (SOFCs) is the sintering of electrolyte into a dense impermeable membrane to prevent the mixing of fuel and oxygen for a sufficiently high open-circuit voltage (OCV). However, herein, we demonstrate a different type of fuel cell, a carbonate-superstructured solid fuel cell (CSSFC), in which in situ generation of superstructured carbonate in the porous samarium-doped ceria layer creates a unique electrolyte with ultrahigh ionic conductivity of 0.17 S⋅cm-1 at 550 °C. The CSSFC achieves unprecedented high OCVs (1.051 V at 500 °C and 1.041 V at 550 °C) with methane fuel. Furthermore, the CSSFC exhibits a high peak power density of 215 mW⋅cm-2 with dry methane fuel at 550 °C, which is higher than all reported values of electrolyte-supported SOFCs. This provides a different approach for the development of efficient solid fuel cells.

Pristine Surface of Ni-Rich Layered Transition Metal Oxides as a Premise of Surface Reactivity.

The surface reactivity of Ni-rich layered transition metal oxides is instrumental to the performance of batteries based on these positive electrode materials. Most often, strong surface modifications are detailed with respect to a supposed ideal initial state. Here, we study the LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode material in its pristine state, hence before any contact with electrolyte or cycling, thanks to advanced microscopy and spectroscopy techniques to fully characterize its surface down to the nanometer scale. Scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS), solid-state nuclear magnetic resonance (SS-NMR), and X-ray photoelectron spectroscopy (XPS) are combined and correlated in an innovative manner. The results demonstrate that in usual storage conditions after synthesis, the extreme surface is already chemically different from the nominal values. In particular, nickel is found in a reduced state compared to the bulk value, and a Mn enrichment is determined in the first few nanometers of primary particles. Further exposition to humid air allows for quantifying the formed lithiated species per gram of active material, identifying their repartition and proposing a reaction path in relation with the instability of the surface.