Eric Chappel

• PhD
• R&D Project Manager at Debiotech

Les dispositifs microfluidiques actifs ou passifs tels que les micropompes, les microvalves, les mixeurs, Les Labs-on-Chips… présentent un chemin fluidique souvent compliqué. Le calcul des pertes de charges et donc de la résistance hydrodynamique des différents éléments le long de ces chemins fluidiques est une étape clé pour assurer la bonne fonct...

The displacement micropump with passive check valves is an attractive solution for precise insulin infusion in patients with type I diabetes. Unlike most insulin pumps that push insulin from a cartridge using a piston, a displacement micropump will first pull insulin from the reservoir before infusing it into the patient. This dual sequence introdu...

Drug Delivery Devices and Therapeutic Systems examines the current technology and innovations moving drug delivery systems (DDS) forward. The book provides an overview on the therapeutic use of drug delivery devices, including design, applications, and a description of the design of each device. While other books focus on the therapy, the primary e...

Implantable drug delivery systems (IDDS) allow for reduced medication doses that decrease the systemic side effects associated with oral, transdermal, or parenteral drug delivery routes. Localized and controlled drug delivery helps maintain the drug concentration within the therapeutic window and improves patient compliance by the limitation of rep...

Advances in microelectromechanical system (MEMS) technology associated with the search for effective drug delivery systems to improve the treatment of various medical conditions have stimulated the development of innovative microfluidic devices during the last decades. This chapter reviews the most advanced micropump designs dedicated to drug deliv...

A delivery system configured to be secured on a patient skin which comprises a first container having a first variable volume; a second container having a second variable volume; and a skin adherable unit configured to secure the first container and the second container to the patient skin. The medical device may further comprise a containers' inte...

The present disclosure relates to an indicator device which comprises one or several plungers inside an elongated cavity. Said indicator device, is intended to provide to the user at least one information related to the current status of a delivery system. The indicator device comprises at least one movable element configured to reach pre-determine...

Cette troisième et dernière partie de l'article propose une revue des difficultés liées à la compréhension des équations en physique avec, comme mise en perspective, une présentation des répercussions possibles de ce type d'analyse sur l'enseignement des mathématiques et de la physique.

Some drug delivery devices can infuse at a flow rate as low as a few microliters per hour or less. Using a micro flowmeter may be an effective solution for a steady flow, but pulsatile flows are trickier to measure. We will present you some tips to assess the delivery accuracy of your device whatever the flow profile. Particular attention is paid t...

Pour illustrer la Problématique du transfert des mathématiques à la physique, le concept d'équation est étudié en détail à partir d'une revue de la littérature scientifique, en s'appesantissant notamment sur les différentes questions que soulève une équation en physique et la diversité des interventions que peut proposer un enseignant pour en facil...

Le concept d’équation, qui servira de fil rouge tout au long de l’article, n’a pas la même signification en mathématiques et en physique. De nombreuses recherches ont analysé, de manière globale, les différents types de difficultés scolaires associées avec ce transfert de notions entre mathématiques et physique. Cette première partie présente tout...

Some Drug Delivery Devices can infuse at a flow rate as low as a few microliters per hour or less. Using a micro flowmeter may be an effective solution for a steady flow, but pulsatile flows are trickier to measure. We will present you some tips to assess the delivery accuracy of your device whatever the flow profile. Particular attention is paid t...

The invention relates to a pumping device including a pump (1) comprising—a pumping chamber (11) having a variable volume, —an inlet (2) communicating with the pumping chamber (11) and comprising a valve, —an outlet (5) communicating with the pumping chamber and comprising a valve, —an actuator adapted to change the volume of the pumping chamber, —...

Helium is a low-density, inert, monoatomic gas that is widely used in medical applications. In respiratory care, Helium is mainly used as an adjunct therapy for patients with severe upper airway obstruction and asthma. To better understand the action mechanism of helium, the physical properties of several therapeutic gas mixtures with helium are ca...

Alarm fatigue in the hospital environment is a recurring problem that can be solved through technical, human, or organizational considerations. The use of technical factors to get a robust alarm management system is illustrated here by two case studies related to air-in-line detection in peritoneal dialysis and insulin pump occlusion management. Ai...

Passive flow control regulators, also known as passive flow control or autoregulated or pressure-compensated valves, deliver, without external control and energy consumption, a constant flow rate regardless of pressure variations.

Passive valves that deliver a constant flow rate regardless of inlet pressure changes have numerous applications in research, industry, and medical fields. The present article describes a passive spring valve that can be adjusted manually to deliver the required flow rate. The valve consists of a movable rod with an engraved microchannel. The fluid...

Based on our experience in microsystems and bioMEMS, we will share here some best practices and insights about the typical challenges and pitfalls you may encounter in the development process of a microfluidic device.

Table of Content of the book "Drug Delivery Devices and Therapeutic Systems"

The test in the production of microfluidic devices dedicated to medical applications poses several challenges in terms of contamination, reliability, and cost. The present article describes the Design-for-Testability approach used to make an insulin MEMS micropump that can be fully tested in production in a few seconds. Each key functional paramete...

The present invention concerns a medical pump comprising : a . A hard housing comprising a top ( 24 ) and bottom ( 1 ) hard shells , within which a rigid wall ( 3 ) and a movable mem brane ( 2 ) create three distinct chambers ; wherein i . said movable membrane tightly separates said second ( 29 ) and third ( 22 ) chambers ii . said first and third...

Microfluidics refers to the science of handling fluids in microstructures and has been widely used in the medical field to miniaturize conventional drug delivery systems, bioassays, and diagnostics. Microfluidic technology provides improved mass transfer, mixing time, and heat exchange; precise flow control; higher precision; greater reliability an...

The present invention describes the improvements due to alternated actuation cycles to reduce the delivery errors related to the pumping chamber elasticity , the actuator relaxation or hysteresis. The method actuates a pumping device with an optimal driving voltage profile , wherein the pumping device comprises a pumping chamber including a pumping...

The device presented is designed to cause , in a mode of operation referred to as “ normal ” mode , a fluid to flow along this fluid path successively through the first cavity , the filter , the second cavity then the flow restrictor . The device is also designed to cause , in a mode of operation referred to as “ purge ” mode , a fluid to flow alon...

Acknowledgment to Reviewers of Micromachines in 2020

Acknowledgment to Reviewers of Sensors in 2020

This review gives an overview of passive constant flow regulators dedicated to microfluidic applications. Without external control and energy consumption, these devices deliver a constant flow rate regardless of pressure variations, making them very attractive for various microfluidic applications, including drug delivery, flow chemistry, point-of-...

Rigorous peer-review is the corner-stone of high-quality academic publishing. The editorial team greatly appreciates the reviewers who contributed their knowledge and expertise to the journal’s editorial process over the past 12 months. In 2018, a total of 588 papers were published in the journal, with a median time to first decision of 15 days and...

Dear colleagues, In this Special Issue, we invite researchers to submit original research papers, review articles, and short communications addressing technical challenges in developing and manufacturing microfluidic devices for medical and diagnostics applications. The papers can cover all aspects of medical microfluidic devices, including but not...

An infusion device comprises a housing, a cavity arranged into the housing, a reservoir comprising an internal compartment and arranged into the housing, a fluid pathway comprising an outlet in fluid communication with the reservoir internal compartment, a vent device configured for communicating ambient air into the cavity, and a removably occludi...

Passive implantable or portable infusion pumps comprise an energy source to pressurize a drug and a fluidic restriction to determine the delivery rate. MEMS technology enables the design of microfluidic chips that can passively regulate the flow rate and therefore limit the impact of pressure variations on flow accuracy. The device is a triple-stac...

The present invention concerns a medical pump comprising: a. A hard housing comprising a tap (24) and bottom (1) hard shells, within which a rigid wall (3) and a movable membrane (2) create three distinct chambers; wherein i. said movable membrane tightly separates said second (29) and third (22) chambers ii. said first and third chambers have a wa...

Overdrainage in upright position is one of the most prevalent issues in treating hydrocephalus with a cerebrospinal fluid (CSF) shunt. Anti-siphon devices (ASDs) are employed to reduce this problem. A novel microelectromechanical system (MEMS)-based valve, termed Chronoflow device, aims to regulate CSF drainage indifferently of the body posture. Wi...

Acknowledgement to Reviewers of Sensors in 2019

A delivery system configured to be secured on a patient skin which comprises a first container having a first variable volume; a second container having a second variable volume; and a skin adherable unit configured to secure the first container and the second container to the patient skin. The medical device may further comprise a containers' inte...

A delivery system configured to be secured on a patient skin which comprises a first container having a first movable wall and a first storage compartment intended to store a medical fluid; a second container having a second movable wall and a second storage compartment; and a skin adherable unit configured to secure the first container and the sec...

A microfluidic radial diffuser typically comprises a hole in a membrane facing a concentric pillar separated by a small gap where the fluid is forced to flow radially between the membrane and the pillar. Such diffusers are notably used to make passive flow rectification valves for drug delivery devices, wherein several holes are machined into a fle...

The present disclosure relates to an indicator device which comprises one or several plungers inside an elongated cavity. Said indicator device, is intended to provide to the user at least one information related to the current status of a delivery system. The indicator device comprises at least one movable element configured to reach pre-determine...

The present invention relates to an indicator device which comprises one or several plungers inside an elongated cavity. Said indicator device, is intended to provide to the user at least one information related to the current status of a delivery device. The indicator device comprises at least one plunger configured to reach pre-determined positio...

Today, there is a growing interest in providing a wearable injector platform dedicated to the delivery of viscous formulations of drugs. Many bolus injectors, e.g. Pushtronex® system for evolocumab, Onpro® system for pegfilgrastim or Herceptin® SC for trastuzumab, comprise a complex engine that moves a plunger inside a cylindrical reservoir filled...

The present invention describes the improvements due to alternated actuation cycles to reduce the delivery errors related to the pumping chamber elasticity, the actuator relaxation or hysteresis. The method actuates a pumping device with an optimal driving voltage profile, wherein the pumping device comprises a pumping chamber including a pumping m...

In this article is discussed a novel wearable injector technology, which utilises a propellant vapour system to drive the injection, making the device both space- and cost-efficient.

Rigorous peer-review is the corner-stone of high-quality academic publishing[...]

Flow control valves comprise a silicon flexible membrane that deflects against a substrate, usually made of glass, containing pillars, an outlet hole, and anti-stiction features. However, there is a strong interest in using silicon instead of glass as substrate material, as it would simplify the process flow by allowing the use of well controlled a...

Flow control valves comprise a silicon flexible membrane that deflects against a substrate, usually made of glass, containing pillars, an outlet hole, and anti-stiction features. However, there is a strong interest in using silicon instead of glass as substrate material, as it would simplify the process flow by allowing the use of well controlled a...

The invention concerns a flow regulator, made of a stack of 3 plates, respectively a top plate including a flexible membrane (1), a middle plate (2) with pillars and through holes and a bottom plate (3) with fluidic ports, micro channels and through holes (8,9,12). The principle is based on the deformation of the membrane due to the pressure of the...

Numerical simulations based on the classical Marmarou’s model have been carried out to analyse the dynamics of hydrocephalus valves. The evolution of the intracranial pressure in various case studies has been determined with a specific focus on flow control valves. It has been shown that their capability to prevent postural under- and over-drainage...

Passive flow control valves are usually intended to deliver or drain a fluid at a constant rate independently of pressure variations. Microfluidic devices made of a stack of two plates are considered here: the first plate comprises a flexible silicon membrane having through holes while the second plate is a rigid substrate with a cavity, an outlet...

The present invention describes several methods based on the combination of device setting change with patient postural change to make fast and reliable hydrocephalus valve adjustment. The monitoring and the analysis of the pressure gradient values during these changes allow the tuning of the device, the characterization of a patient physiological...

A numerical model based on equivalent electrical networks has been built to simulate the dynamic behavior of a positive-displacement MEMS micropump dedicated to insulin delivery. This device comprises a reservoir in direct communication with the inlet check valve, a pumping membrane actuated by a piezo actuator, two integrated piezoresistive pressu...

The device presented is designed to cause, in a mode of operation referred to as "normal" mode, a fluid to flow along this fluid path successively through the first cavity, the filter, the second cavity then the flow restrictor. The device is also designed to cause, in a mode of operation referred to as "purge" mode, a fluid to flow along this same...

Electrical equivalent networks have been used to simulate a piezoelectric driven MEMS micropump dedicated to insulin delivery. The numerical model has been validated using experimental data. The pressure profiles delivered by integrated sensors are intended to be analyzed in a continuous way during the therapy. Any failure like occlusion, valve lea...

Passive flow regulators are usually intended to deliver or drain a fluid at a constant rate independently from pressure variations. Microfluidic devices made of a stack of two plates are considered here: the first plate comprises a flexible silicon membrane having through holes while the second plate is a rigid substrate with a cavity, an outlet ho...

A passive valve able to deliver a constant flow rate independently of inlet pressure changes is proposed. The valve, which comprises a hollow cylinder, a piston engraved with a helical groove, a spring and two fluidic connectors, is adapted by design to high pressures and high flow rates. However, it has been shown that this technology is also suit...

Electrical equivalent networks have been used to simulate a piezoelectric driven MEMS micropump dedicated to insulin delivery. The numerical model has been validated using experimental data. The pressure profiles delivered by integrated sensors are intended to be analyzed in a continuous way during the therapy. Any failure like occlusion, valve lea...

Passive flow regulators are usually intended to deliver or drain a fluid at a constant rate independently from pressure variations. Microfluidic devices made of a stack of two plates are considered here: the first plate comprises a flexible silicon membrane having through holes while the second plate is a rigid substrate with a cavity, an outlet ho...

A method actuates a pumping device that has an optimal driving voltage. The pumping device includes a pumping chamber that has a pumping membrane, an inlet and an outlet chamber, a voltage controlled actuator connected to the pumping membrane, a stop position defined by a mechanical stop, and a sensor for determining whether the pumping membrane ha...

The present invention concerns a medical pump comprising: a. A hard housing comprising a top (24) and bottom (1) hard shells, within which a rigid wall (3) and a movable membrane (2) create three distinct chambers; wherein i. said movable membrane tightly separates said second (29) and third (22) chambers ii. said first and third chambers have a wa...

The present invention relates to infusion systems and more precisely to the detection of dysfunctions in the performance or efficiency of such systems.

The present invention describes a valve for controlling the passage of a microfluidic system. Said valve comprises a first valve element (103) and a second valve element (104, 105) with respective first and second contact surfaces which are placed opposite to each other in such a way as to control a fluid flow through said passage. Said first valve...

An adjustable passive flow regulator may be used in the field of drug delivery (liquid or gaseous, e.g. for pain management) or for draining cerebrospinal fluid (CSF) for hydrocephalus patient.

Improved glycemic control with insulin pump therapy in patients with type 1 diabetes mellitus has shown gradual reductions in nephropathy and retinopathy. More recently, the emerging concept of the artificial pancreas, comprising an insulin pump coupled to a continuous glucose meter and a control algorithm, would become the next major breakthrough...

PROBLEM TO BE SOLVED: To provide several improvements with respect to state-of-the-art devices and methods.SOLUTION: The present invention relates to a pumping device including a pump 1, the pump 1 comprising: a pumping chamber 11 having a variable volume; an inlet 2 communicating with the pumping chamber 11 and including a valve; an outlet 5 commu...

The regulator comprises at least a cylinder (2) with a fluid inlet connector (1) for receiving fluid at an inlet pressure and a fluid outlet connector (4) for delivering fluid, at least one chamber (3), a rod (5) in said cylinder with one side submitted to the inlet pressure and the other side submitted to the outlet pressure generating a net force...

The invention concerns a flow regulator, made of a stack of 3 plates, respectively a top plate including a flexible membrane (1), a middle plate (2) with pillars and through holes and a bottom plate (3) with fluidic ports, micro channels and through holes (8,9,12). The principle is based on the deformation of the membrane due to the pressure of the...

The invention relates to a method for detecting abnormality of at least one function of an infusion assembly. The infusion assembly comprises pumping equipment comprising a pump (1), wherein the pumping equipment further comprises a pumping chamber (11), an inlet (2), an outlet (5), an actuator, a fluid path, a pressure sensor (4) and a processing...

The concept of artificial pancreas, which comprises an insulin pump, a continuous glucose meter and a control algorithm, is a major step forward in managing patient with type 1 diabetes mellitus. The stability of the control algorithm is based on short-term precision micropump to deliver rapid-acting insulin and to specific integrated sensors able...

Passive flow regulators are usually intended to deliver or drain a fluid at a constant rate independently from pressure variations. New designs of passive flow regulators made of a stack of a silicon membrane anodically bonded to a Pyrex substrate are proposed. A first design has been built for the derivation of cerebrospinal fluid (CSF) towards pe...

The concept of artificial pancreas, which comprises an insulin pump, a continuous glucose meter and a control algorithm, is a major step forward in managing patient with type 1 diabetes mellitus. The stability of the control algorithm is based on short-term precision micropump to deliver rapid-acting insulin and to specific integrated sensors able...

Debiotech SA, une entreprise spécialisée dans la conception d'instruments médicaux, développe actuellement une micropompe de type patch destinée au traitement du diabète. Cette pompe est construite à partir d'un composant MEMS qui possède un actionneur piezo-électrique externe capable de délivrer une force importante tout en ayant une course très f...

A fluid flow regulator (1) of the passive type is disclosed which has a fluid inlet adapted to be connected to a fluid reservoir and a fluid outlet (13) adapted to be connected to a patient's body. The regulator comprises a rigid substrate (2) and a resilient membrane (3) tightly linked together so as to define a cavity (6) there between which is d...

The micro-pump has a pumping chamber (4) communicating with exterior via a flexible diaphragm (2). The diaphragm is secured to an actuator (5) e.g. piezoelectric bi-morph or multi-morph actuator or shape memory alloy actuator, arranged at the exterior of the micro-pump. The diaphragm is secured to the actuator by an element that is in the form of a...

Sensor for dynamically detecting the residual liquid volume V res of a collapsible reservoir (1,3) characterized by the fact that it is adapted to detect a threshold pressure P th which corresponds to a phase within said reservoir (1,3) when only said residual liquid volume V res remains, said residual volume V res corresponding to a safety volume...

The present invention describes the improvements due to alternated actuation cycles to reduce the delivery errors related to the pumping chamber elasticity, the actuator relaxation or hysteresis. The method actuates a pumping device with an optimal driving voltage profile, wherein the pumping device comprises a pumping chamber including a pumping m...

Method for detecting possible under or over delivery of a micropump having at least an inlet valve, a pumping chamber with an inner pressure sensor and an outlet valve, said method comprising the determination of the pump tightness via the measurement of the pressure change in said pumping chamber during at least part of the pumping cycle when the...

A device for delivering a liquid including a pump, and an anti-siphon valve external to the pump is disclosed. The anti-siphon valve includes an inlet channel connected to the outlet duct of the pump, and an outlet channel, between which a seat and a moving member are disposed that are suitable for co-operating together and that define, between the...

Diabetes is a chronic condition that occurs when the pancreas does not produce enough insulin or when the body cannot effectively use the insulin it produces. Several medical devices are commonly used to inject insulin into the patients: syringes, pens, conventional pumps. The presentation deals with a new insulin pump concept, based on MEMS techno...

Infusion Micro-Pump Development Using MEMS Technology

We report on original industrialized functional testing methods for insulin micropumps. A specific Design-For-Test associated with the analysis of the integrated pressure sensor signal, during a specific actuation profile, allows a complete characterization of the pump functionality in few seconds. All critical failures due to fabrication and assem...

A method of measuring a volume in a fluid flow micromechanical device includes: a) providing and positioning an optical apparatus for measuring the profile of a surface; b) providing a device for acquiring and processing the images coming from the optical apparatus for measuring a profile; c) placing the moving member in a first position and then i...

We report on the fabrication of the first MEMS micropump including an integrated pressure sensor. The signal of this sensor allows direct insight into the pump's operating dynamics and enables real-time self-monitoring. We demonstrate the changes in the sensor signal under different pumping conditions, including the presence of air in the pumping c...

Flow regulator for the infusion of medicaments, comprising, in succession, a substrate (1), a channel (5), a spacer (3) and a membrane (4), the latter having at least one hole (6) communicating with the channel (5), characterized in that the regulator is produced from at least two separate elements (1-4), the first element comprising the membrane (...

Les actionneurs électromagnétiques sont très largement utilisés à l’échelle macroscopique. La force motrice d’un actionneur électromagnétique résulte de l’interaction entre des aimants permanents et le champ magnétique induit par le courant circulant dans une bobine. Cette force sans contact confère à ce type d’actionneur une densité d’énergie élev...

Mixed Layered Oxide Phases NaxLi1-xNiO2: A Detailed Description of Their Preparation and Structural and Magnetic Identification. — The title compounds (0 ≤ x ≤ 0.3 and 0.8 ≤ x ≤ 1.0) are synthesized by solid state reactions of Na2O2, NiO, and LiOH·H2O (680 °C, 24 h). The samples are characterized by powder XRD and magnetic measurements. The Li-rich...

The mixed layered oxide phases NaxLi1−xNiO2 were prepared and characterised by X-ray diffraction, chemical analysis and a thorough magnetic study. Single phase compounds were obtained for the nominal compositions 0⩽x⩽0.3 and 0.8⩽x⩽1.0. The chemical analysis reveals that only up to 6% of sodium can actually be substituted for lithium in the lithium-...

The use of a compact disc pickup head is investigated here for the measurement of membrane displacements during the actuation of a MEMS micropump. CD pickup heads have been already employed for autocollimation, profilometry, Raman spectrometry, interferometry, the monitoring of AFM cantilevers or fetal heartbeats. This technology, developed in the...

In the Li1-xNaxNiO2 solid solutions, three different single-phase regions exist: for xgreater than or equal to0.9, for xapproximate to0.7, and for xless than or equal to0.3. Although the intermediate compound does not show the cooperative Jahn-Teller transition of NaNiO2, its magnetic properties remain very similar, particularly with respect to the...

DEBIOTECH has developed a high-accuracy silicon mi-cropump for drug delivery and liquid micro dosing. The microsystem has the capability of ensuring a constant stroke volume in the range of 150 nl independent of external conditions such as the outlet pressure, the temperature and the liquid viscosity. The pump chip is the heart of a novel, highly m...

Structural changes occurring upon electrochemical delithiation in LixCo1−yFeyO2 solid solutions have been examined using in-situ electrochemical X-ray diffraction on plastic batteries, for y = 0.1, 0.2, 0.4 and 0.7. Two key points are emphasised in this study: (i) the influence of partial iron substitution on the LixCoO2 phase diagram, especially r...

Structural changes occurring upon electrochemical delithiation in Li x Co 12y Fe y O 2 solid solutions have been examined using in-situ electrochemical X-ray diffraction on plastic batteries, for y ~ 0.1, 0.2, 0.4 and 0.7. Two key points are emphasised in this study: (i) the influence of partial iron substitution on the Li x CoO 2 phase diagram, es...

LiNi1−yFeyO2 samples were prepared either by nitrate or oxide methods. Using X-ray diffraction and Rietveld refinements, we show that single-phase products, iso-structural to LiNiO2 (R−3m space group) can be obtained in the 0≤y≤0.3 range. From AC magnetic susceptibility and magnetisation measurements, we have determined the role of the extra 3d cat...

Susceptibility, high-field magnetization and submillimeter wave electron spin resonance measurements of layered quasi-stoichiometric Li1-xNi1+xO2 are reported and compared to isomorphic NaNiO2. A new mechanism of magnetic frustration induced by the excess Ni ions always present in the Li layers is proposed. We finally comment on the possible realiz...

Layered LiFe1-xCoxO2 compounds have been studied by powder- neutron diffraction in the temperature range 1.5 100 K and at room temperature. The Bragg reflections of LiFe1-xCoxO2 can he indexed in the R-3m space group. At low temperatures, for x < 0.6 samples, an A-type AF structure is observed with a propagation vector k = [00(1)/(2)] and a magneti...

Mixed lithium-transition metal oxides LiFe1-xCoxO2 (0 less than or equal to x less than or equal to 1) have been studied by powder neutron diffraction in the temperature range 1.5-100 K and at room temperature. The low-temperature data analysis of the high-flux neutron diffraction patterns reveals an antiferromagnetic arrangement with a propagation...

Ball-milling induces high values of microstrain and a rapid decrease of the crystallite size in SmCo5 powders. However, milling is found to be less aggressive to SmCo5 when it is milled together with a ceramic antiferromagnet, such as NiO. In addition, as the milling proceeds, SmCo5 particles are progressively surrounded and soldered to NiO, finall...

The room-temperature coercivity, HC, and squareness, MR/MS (remanence/saturation magnetizations), of permanent magnet, SmCo5 powders have been enhanced by ball milling with antiferromagnetic NiO (with Néel temperature, TN = 590 K). This enhancement is observed in the as-milled state. However, when the milling of SmCo5 is carried out with an antifer...

The low field magnetic susceptibility and X-band ESR spectra of quasi-stoichiometric Li1−xNi1+xO2 samples have been measured. The anomaly around 240K, observed in Li0.98Ni1.02O2 under a 1mT field, disappears under the conventional magnetic fields used in ESR or susceptibility measurements. We comment on the distribution of extra Ni ions in the lith...