Gallium Accumulation Research Articles

Boosting lung accumulation of gallium with inhalable nano-embedded microparticles for the treatment of bacterial pneumonia

The potential of intra-venous gallium nitrate (GaN) administration against Pseudomonas aeruginosa pneumonia was recently demonstrated in mice and in cystic fibrosis (CF) patients. Likewise, the added value of direct lung delivery of Ga(III) has been shown in rats. Therefore, the design of a drug delivery system specifically engineered for Ga(III) inhalation is imperative to improve its accumulation in lungs. To this purpose, Ga(III) was efficiently encapsulated into hyaluronic acid/chitosan nanoparticles (Ga_HA/CS NPs), whose features were tuned to facilitate access to the target by overcoming mucus and biofilm surrounding bacteria. Then, to improve in vivo lung deposition, Ga_HA/CS NPs were engineered into mannitol-based NEM (Ga_Man NEM). The powders showed optimal in vitro aerosol performance, and sustained release kinetics in lung lining fluids. Moreover, good tolerability and antimicrobial properties were shown in vitro. Intratracheal insufflation of Ga_Man NEM in rats resulted in a significant improvement of Ga(III) persistence in the lungs coupled to a lower Ga(III) concentration in plasma and urine, compared to GaN solution. Noteworthy, the developed formulation significantly modifies the unfavorable Ga(III) kinetic increasing the Ga(III) to the lung and preventing Ga(III) accumulation in the kidney, key responsible for adverse effects, conclusively demonstrating the benefit of Ga_Man NEM to exploit the therapeutic effect of Ga(III) via inhalation route.

Induced Optical Losses in Optoelectronic Devices due Focused Ion Beam Damages

A study of damages caused by gallium focused ion beam (FIB) into III-V compounds is presented. Potential damages caused by local heating, ion implantation, and selective sputtering are presented. Preliminary analyzes shows that local heating is negligible. Gallium implantation is shown to occur over areas tens of nanometers thick. Gallium accumulation as well as selective sputtering during III-V compounds milling is expected. Particularly, for GaAs, this effect leads to gallium segregation and formation of metallic clusters. Microdisks resonators are fabricated using FIB milling with different emission currents to analyze these effects on a device. It is shown that for higher emission current, thus higher implantation doses, the cavity quality factor rapidly decreases due optical scattering losses induced by implanted gallium atoms.

Accumulation of gallium (Ga) and indium (In) in rice grains in Ga- and In-contaminated paddy soils

To understand the risk of two emerging contaminants, gallium (Ga) and indium (In) to humans via rice consumption, effects of soil properties and concentrations of spiked Ga/In on the accumulation of Ga and In in rice grains were investigated. A pot experiment was conducted, and paddy rice was grown in three soils with different pH values and Al availabilities (i.e., Pc, TWz and Cf), which were spiked with various Ga and In concentrations. The growth index and concentrations of Ga, In, and Al in plant tissues and soil pore water were measured. Results revealed that the concentrations of Ga and In in soil pore water increase with the spiking of Ga or In in all of the tested soils, but the biomass of roots and shoots does not significantly decrease. The accumulation of Ga in shoots and brown rice was significantly reduced in high available Al acidic soils (Pc soils), but this accumulation was significantly increased in low available Al acidic soils (TWz soils), which can be explained by the competitive uptake between Ga and Al by rice plants. The extent of competitive effects between In and Al was less than that between Ga and Al because of the lower solubility and translocation capability of In than those of Ga in soil–rice systems. However, significant differences in the concentrations of Ga and In in brown rice in neutral soils (Cf soils) among the Ga or In treatment were not observed. In addition, the iron plaque formed on the root surface can serve as a barrier to reduce the accumulation of Ga in rice plants. This study suggested that the risk of accumulation of Ga and In in rice grains should be of concern when paddy rice is grown in acidic Ga- or In-contaminated soils with low Al availability.

Unambiguously Enhanced Ultraviolet Luminescence of AlGaN Wavy Quantum Well Structures Grown on Large Misoriented Sapphire Substrate

AbstractHigh‐quality epitaxy consisting of Al1−xGaxN/Al1−yGayN multiple quantum wells (MQWs) with sharp interfaces and emitting at ≈280 nm is successfully grown on sapphire with a misorientation angle as large as 4°. Wavy MQWs are observed due to step bunching formed at the step edges. A thicker QW width accompanied by a greater accumulation of gallium near the macrostep edge than that on the flat‐terrace is observed on 4° misoriented sapphire, leading to the generation of potential minima with respect to their neighboring QWs. Consequently, a significantly enhanced photoluminescence intensity (at least ten times higher), improved internal quantum efficiency (six times higher at low excitation laser power), and a much longer carrier lifetime are achieved. Importantly, the wafer‐level output‐power of the ultraviolet light emitting diodes on 4° misoriented substrate is nearly increased by 2–3 times. This gain is attributed to the introduction of compositional inhomogeneities in AlGaN alloys induced by gallium accumulation at the step‐bunched region thus forming a lateral potential well for carrier localization. The experimental results are further confirmed by a numerical modeling in which a 3D carrier confinement mechanism is proposed. Herein, the compositional modulation in active region arising from the substrate misorientation provides a promising approach in the pursuit of high‐efficient ultraviolet emitters.

Mineralization zoning of coal-metal deposits in China

Substantive progress has been made in extracting germanium, gallium, rare earth elements (REEs), lithium, and other metals from coal. Coal deposits are becoming important sources of many strategic metal resources. However, ore deposit theory study for coal-metal resources has not been systematic. This paper summarizes the mineralization characteristics of germanium, gallium, lithium, and REEs in coal on the basis of previous research results and field investigations, including those on seven metallogenic zones of coal metal deposits in China. Coal-germanium deposits, products of magmatic hydrothermal activity, mainly occur in low rank coal in the areas of Erlian, the Hailaer Basin, Inner Mongolia, and the Sanjiang district in the Yunnan Province. Occasionally, rich-germanium-coal can be found in other areas. Coal-gallium deposits are mainly in the Permian coal of North China, Jurassic coal of Northwest China, and late-Permian coal of South China. The accumulation of gallium in coal is closely related to aluminum-containing minerals. Coal-lithium deposits mainly occur in the Zhungeer coal field, Inner Mongolia, the Pingshuo coal field, and the Jingcheng coal field in the Shanxi Province, and some coal fields in South China. Similarly to gallium, the accumulation of lithium in coal is also closely related to aluminum-containing minerals. Coal-REE deposits mainly occur in the Early Jurassic coal of the Erlian Basin and Inner Mongolia, and Late Permian coal in South China. REEs of Erlian basin coal likely entered in ionic forms in early stages of coal or peat bog formation. REEs of South China coal are likely associated with REE-rich trass volcanic ash which deposited synchronously with peat bog accumulation. Abundant abnormal metal elements in coal are important for classification of metallogenic zones. Regional tectonic background and evolution, characteristics of stratigraphic sedimentary environment, and coal quality are also important factors. (1) Delineation of germanium metallogenic zones in the coal follows the principles that: coal in the coal area should be low-metamorphic bituminous (long-flame) coal; the basement of the coal-bearing basin was broken and faults developed in the region; and there are obvious traces of hydrothermal intrusion in or around the coal measures in the zone. (2) Delineation of gallium metallogenic zones in coal is based on these traits: an obvious gallium source should exist in the region; the provenance area has favorable weathering and denudation conditions; and an aluminum-gallium formation under strong leaching is contained within. (3) Delineation of lithium metallogenic zones in coal requires: relatively clear sources of lithium in the zones; favorable weathering and denudation conditions in the provenance area; and aluminum-lithium containing rocks under strong leaching. (4) Delineation of rare earth mineralization zones in coal is based on: large scale volcanic eruptions in or near peat bogs during the accumulation period, with tuff in the coal-bearing strata; and hydrothermal intrusion into coal-measure strata during the peat bog period or early coal-forming period. According to the principles above, seven coal-metal metallogenic zones were identified, including: (1) the Erlian Basin-Hailaer Basin coal-germanium and REE deposit zone; (2) the Tianshan coal-gallium deposit zone; (3) the South-Yinshan coal-gallium-lithium deposit zone; (4) the East-Taihang Mountain coal-gallium deposit zone; (5) the Qilian-Qinling coal-gallium-lithium deposit zone; (6) the Sichuan-Yunnan-Guangxi coal-gallium-lithium and REE deposit zone; and (7) the Sanjiang (west Yunnan Province) germanium deposit zone.

Influence of Cu on Ga diffusion during post-selenizing the electrodeposited Cu/In/Ga metallic precursor process

Gallium accumulation, caused by faster reaction of indium with Se than gallium with Se, is a critical issue for post-selenization process, which limits the optimization of surface energy bandgap and open circuit voltage of CIGSe thin film solar cell. In this study, large-grained and compact CIGSe thin film was successful fabricated by electrodeposition and a three-step vapor Se/N2/vapor Se reaction process. The influence of the Cu content on gallium diffusion and grain growth of CIGSe thin film was studied. The compositions, element distributions, and morphologies of CIGSe thin films were studied. The results revealed that the gallium diffused homogenizely through the film with Cu/(In+Ga) < 0.9, while accumulated at the back contact region with Cu/(In+Ga) > 0.9. Single phase and large-grained CIGSe thin films were obtained with Cu/(In+Ga) ratios between 0.78 and 0.9. Cu(In,Ga)Se2 solar cells made with the CIGSe thin films presented highest efficiency of 11.22%. The solar cell based on the single phase and large-grained CIGSe absorber with Cu/(In+Ga) = 0.85 presents highest conversion efficiency of 11.22%, fill factor of 63.83% and VOC of 514 mV.

A case of neurosarcoidosis with recurrent brainstem infarction, obstructive hydrocephalus and brainstem atrophy

We report the case of a 42-year-old female with neurosarcoidosis who was hospitalized in year 2017 for gait disturbance. In 2011, she suddenly had vertigo that lasted for a few days. In 2013, she noticed left hemiplegia. A brain MRI revealed an acute infarction on the right side of the upper pons extending longitudinally from the ventral surface. In 2017, she again had left lower limb paralysis. A Brain MRI showed another infarction on the right side of the mid-pons. Hydrocephalus and brainstem atrophy were also noted. The patient was referred to our hospital. Upon neurological examination, she presented with down beat nystagmus, muscle weakness on the left side, and a broad-based spastic gait. CSF findings included an increased number of cells and protein levels with decreased glucose levels. A contrast-enhanced MRI revealed basilar meningitis causing hydrocephalus. A contrast CT scan revealed inguinal lymph node swelling, and scintigram found gallium accumulation. We diagnosed sarcoidosis via a lymph node biopsy. We speculate that chronic basilar meningitis obstructed the patient's branching penetrating arteries inducing infarction together with obstruction of the spinal fluid flow causing hydrocephalus and cerebral atrophy.

Interaction of liquid water with the p-GaInP2(100) surface covered with submonolayer oxide.

High-resolution surface-sensitive synchrotron radiation photoelectron spectroscopy was used to study the interaction of water with the p-GaInP2(100) surface covered with submonolayer residual native oxide in order to get insight into water dissociation at the solar water-splitting photocathodes in real liquid environment. In the surface-sensitive valence band spectra features related to Ga-OH, In-OH, and H-In-OH bonds appear after emersion of the p-GaInP2(100) surface from liquid water at room temperature. Indium core levels remain intact after emersion, while the gallium core levels indicate transformation of gallium oxides to hydroxides, as well as the accumulation of metallic gallium. Surface sensitive P 2p core level spectra indicate formation of P-H bonds after emersion. These changes of the surface chemical bonds can be attributed to the dissociation of the water molecules on the p-GaInP2(100) surface, leading to the subsequent transformation of surface oxides to hydroxides. Interaction of water with the p-GaInP2(100) surface covered with submonolayer residual native oxide causes an increase in the work function by 80 meV and a modification of the valence band edge spectrum, which is evidence of a change of the surface dipole due to the charge redistribution induced by the transformation of the surface oxides to hydroxides.

Growth of AlGaN under the conditions of significant gallium evaporation: Phase separation and enhanced lateral growth

The growth kinetics of AlGaN in NH3 MBE under significant Ga desorption was studied. It was found that the addition of gallium stimulates 2D growth and provides better morphology of films compared to pure AlN. The effect was experimentally observed at up to 98% desorption of the impinging gallium. We found that under the conditions of significant thermal desorption, larger amounts of gallium were retained at lateral boundaries of 3D surface features than at flat terraces because of the higher binding energy of Ga atoms at specific surface defects. The selective accumulation of gallium resulted in an increase in the lateral growth component through the formation of the Ga-enriched AlGaN phase at boundaries of 3D surface features. We studied the temperature dependence of AlGaN growth rate and developed a kinetic model analytically describing this dependence. As the model was in good agreement with the experimental data, we used it to estimate the increase in the binding energy of Ga atoms at surface defects compared to terrace surface sites using data on the Ga content in different AlGaN phases. We also applied first-principles calculations to the thermodynamic analysis of stable configurations on the AlN surface and then used these surface configurations to compare the binding energy of Ga atoms at terraces and steps. Both first-principles calculations and analytical estimations of the experimental results gave similar values of difference in binding energies; this value is 0.3 eV. Finally, it was studied experimentally whether gallium can act as a surfactant in AlN growth by NH3 MBE at elevated temperatures. Gallium application has allowed us to grow a 300 nm thick AlN film with a RMS surface roughness of 2.2 Å over an area of 10 × 10 μm and a reduced density of screw dislocations.

A crab-like fluorescent probe for Ga(III) detection in body fluids and biological tissues

The application of Ga-based compounds in medical and industrial fields could induce accumulation of gallium in the human body, and further exert certain Ga-toxic effect on health. So it is very important for gallium detection in biological aspects and different environments. Fluorescent analysis owning various merits surpass other analytic methods and received great attention recently. In this work, a biomimetic crab-like fluorescent probe denoted as NL was designed and successfully synthesized, which can selectively recognize Ga3+ from other metal ions in acetate buffer/DMSO (v/v=1/1, pH=5. 2), and the limit of detection was 12. 89nM. Moreover, this probe can detect Ga3+ in complex environments, such as human serum and urine, pork, rabbit kidney and rabbit liver, and even in simulated pollution water. Besides, the proposed method can provide portable test for Ga3+ and reach a detection limit to 1. 2mg/Kg by naked eye under ultraviolet irradiation, which is lower than the toxic concentration (4mg/Kg) of Ga3+ permitted in organs. The results indicated that NL can be further applied in clinical examination and environmental detection, and the biomimetic designing can provide reference to the development of other fluorescent sensors.

Synchrotron Photoemission Spectroscopy Study of p-GaInP2(100) Electrodes Emersed from Aqueous HCl Solution under Cathodic Conditions

(Photo)electrochemical processes occurring under cathodic polarization at the p-GaInP2(100)/1 M HClaq solution interface were investigated in detail by high-resolution surface sensitive synchrotron-radiation photoemission spectroscopy. It was found that on application of the cathodic bias in the dark to the p-GaInP2(100)/1 M HClaq solution interface the electrochemical processes are started at a bias of about −1.0 V vs reversible hydrogen electrode (RHE), where cathodic current passing through the semiconductor/electrolyte interface starts to rise. Under higher cathodic bias applied in the dark, hydroxyl groups and metallic gallium are accumulated at the surface, which is accompanied by a decrease in work function of the semiconductor. Accumulation of hydroxyl groups can be related only to splitting of water molecules at the semiconductor/electrolyte interface, since the aqueous HCl solution contains no hydroxyl groups intrinsically. Accumulation of hydroxyl groups and metallic gallium is accelerated under visible light illumination, which indicates participation of photogenerated electrons in the surface electrochemical reactions. The formation of the metallic gallium without simultaneous metallic indium formation testifies that the In–P bonds of the GaInP2 compound are more stable against cathodic corrosion than the Ga–P bonds.

Primary Adrenal Leiomyosarcoma in an Aged Japanese Woman: A Rare Case Report

Primary adrenal leiomyosarcoma is an extremely rare tumor. Here, we report the case of a primary adrenal leiomyosarcoma in an 81-year-old woman. Computed tomography showed a right adrenal tumor (7 cm). There were no abnormal findings on physical examination and her serum adrenal hormone levels were normal. However, 67Gallium scintigraphy showed gallium accumulation at the site of a right adrenal tumor, and malignancy was suspected. The right adrenal tumor was surgically removed and histological examination revealed that it was a leiomyosarcoma. After surgical treatment, the patient was administered different types of chemotherapy but she died of local recurrence 1 year later

A Comparative Photoelectron Spectroscopic Analysis of MBE and MOCVD Grown Epitaxial GaN Films

The report presents X-Ray Photoelectron Spectroscopic analysis of as-received and cleaned MBE and MOCVD grown undoped epitaxial GaN films. We correlate observed changes in electronic structure and surface properties after employing a newly derived approach to clean GaN surfaces. The adopted approach is a combination of two different standard cleaning procedures consisting of ex-situ wet chemical (HCl) etching followed by an in-situ ultrahigh vacuum anneal (up to 750 °C), and successfully yielded a clean and stoichiometric GaN surface. The method was employed to investigate cleanliness of MBE and MOCVD grown GaN films and it was observed that major contaminants such as carbon and oxygen were significantly removed from the surface. XPS analysis revealed that MBE grown films show higher amount of surface contamination than the MOCVD grown films but can also be cleaned more efficiently. Thermal annealing (≥ 750 °C) resulted in the dissociation of GaN bonds and accumulation of metallic gallium on the surface on MOCVD grown GaN films, which was confirmed by core level as well as the valence band spectra. The n O/n N ratio of the films reduced drastically from 1.79 to 0.04 and 0.73 to 0.09 after cleaning with the stoichiometry (N:Ga) of 1.0 ± 0.04 and 1.1 ± 0.05 for MBE and MOCVD grown GaN films respectively. The VB maximum position of MBE and MOCVD grown films was observed to be shifted from 2.9 ± 0 eV to 2.2 ± 0.1 eV and 2.8 ± 0.1 eV to 1.4 ± 0.1 eV after cleaning of the surface.

Thermal etching process of microscale pits on the GaAs(001) surface

AbstractWhen a GaAs(001) substrate is heated up to 650 °C in a scanning electron microscope (SEM) vacuum chamber with vacuum range from 10–4 Torr to 10–5 Torr, real‐time SEM observation reveals microscale pits on GaAs substrate surface. The annealing process of GaAs substrate in vacuum causes excess evaporation of arsenic and accumulation of gallium as liquid droplets on the surface. As the function of electrochemical drills, the gallium droplets etch away GaAs beneath the surface to make microscale holes on GaAs substrate. With small amount of oxygen in the chamber acting as etching catalyst, gallium droplets etch GaAs much faster than in ultra‐high vacuum (UHV) MBE chamber. This process provides an easy technique to fabricate microscale pits on GaAs(001) surface.magnified imageTop view of microscale pits, (a) 8000× magnification view of pit; (b) 15000× magnification view of pit.(© 2012 WILEY‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

Analysis of Focused Ion Beam Damages in Optoelectronic Devices Fabrication

A study of the damages caused by gallium focused ion beam (FIB) is presented. Potential damages caused by local heating, ion implantation, and selective sputtering are presented. Preliminary analysis shows that local heating is negligible. Gallium implantation is shown to occur over areas tens of nanometers thick. Gallium accumulation as well as selective sputtering during III-V compound milling is expected. Particularly, for GaAs, this effect leads to gallium segregation and the formation of metallic clusters. Microdisks resonators are fabricated using FIB milling of different emission currents. It is shown that for higher emission current, thus higher implantation doses, the cavity quality factor rapidly decreases.

Microstructural and electrical characteristics of rapidly annealed Ni/Mo Schottky rectifiers on cleaned n-type GaN (0001) surface

We have investigated the electrical and microstructural properties of Ni/Mo Schottky rectifiers to n-type GaN by current–voltage (I–V) and transmission electron microscopy (TEM) before and after annealing at 600 °C. The obtained barrier height for as-deposited Ni/Mo contact is 0.66 eV. It is observed that the barrier height increases with annealing temperature up to 500 °C, reaching a maximum value of 0.75 eV at this temperature. However, the Schottky barrier height of the Ni/Mo Schottky contact slightly decreased to 0.67 eV (I–V) when the contact was annealed at 600 °C. According to the HRTEM, STEM and EDX analysis, the formation of Ga-Ni interfacial layer at the interface results in the accumulation of gallium vacancies near the surface of the GaN layer. This could be the reason for increase in barrier heights upon annealing at elevated temperatures. The variation in the measured barrier height after annealing at 600 °C may be due to the formation of native oxide layer at the interface compared to the 500 °C annealed contact.

The gallium complex KP46 exerts strong activity against primary explanted melanoma cells and induces apoptosis in melanoma cell lines

The antineoplastic properties of gallium are well documented. Owing to their robust accumulation of gallium, melanoma cells should be amenable to gallium-based anticancer drugs. With the aim of improving the disappointingly low activity of inorganic gallium salts, we have developed the orally bioavailable gallium complex KP46 [tris(8-quinolinolato)gallium(III)] that had already been successfully studied in a phase I clinical trial. To assess its therapeutic potential in malignant melanoma, its antiproliferative effects were investigated in series of human cell lines and primary explanted melanoma samples by means of the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and the Human Tumor Cloning Assay, respectively. When compared with other cell lines, the majority of melanoma cells rank among the KP46-sensitive cell lines (50% inhibitory concentration values: 0.8-3.7 micromol/l). Clinically achievable concentrations of KP46 proved to be highly effective in melanoma cells from primary explants of cutaneous and lymph node metastases. Colony growth was inhibited in 10 of 10 specimens by 5 micromol/l KP46 (corresponding to the steady-state plasma concentration measured earlier in a study patient) and in four of 10 specimens by 0.5 micromol/l KP46. In-vitro potency of KP46 is higher than that of dacarbazine or fotemustine and comparable with that of cisplatin. The effects induced by KP46 in melanoma cell lines involve cell-cycle perturbations (S-phase arrest) and apoptosis (activation of caspase-9, PARP [poly(ADP-ribose) polymerase] cleavage, formation of apoptotic bodies). No effects on DNA secondary structure could be observed in an electrophoretic mobility shift assay using double-stranded plasmid DNA. Thus, further studies on the therapeutic applicability of KP46 in malignant melanoma are warranted.

Running Droplets of Gallium from Evaporation of Gallium Arsenide

High-temperature annealing of gallium arsenide in vacuum causes excess evaporation of arsenic, with accumulation of gallium as liquid droplets on the surface. Using real-time in situ surface electron microscopy, we found that these droplets spontaneously run across the crystal surface. Running droplets have been seen in many systems, but they typically require special surface preparation or gradient forces. In contrast, we show that noncongruent evaporation automatically provides a driving force for running droplets. The motion is predicted and observed to slow and stop near a characteristic temperature, with the speed increasing both below and above this temperature. The same behavior is expected to occur during the evaporation of similar III-V semiconductors such as indium arsenide.

Steroid treatment deteriorated ventricular tachycardia in a patient with right ventricle-dominant cardiac sarcoidosis

We report a case of a patient with cardiac sarcoidosis presenting with a non-sustained ventricular tachycardia (VT), mimicking arrhythmogenic right ventricular cardiomyopathy. After the pathological diagnosis and confirmation of gallium-67 uptake by the myocardium, corticosteroid therapy was initiated. The myocardial gallium accumulation disappeared shortly after the treatment, but the VTs deteriorated into multifocal and sustained VTs almost all day. Those drug-refractory VTs were finally controlled with 3 catheter ablation sessions.

Bell-shaped sensory impairments of all modalities in a neurosarcoidosis patient

We describe a 45-year-old man with neurosarcoidosis complaining of bell-shaped tightening and pain with sensory disturbance of superficial and deep sensations. The patient showed subacute progressive sensory impairment in bilateral C7-Th12 dermatomes. Triceps and patellar tendon reflexes were decreased. Chest X-ray revealed bilateral hilar lymphadenopathy without pleural effusion. There was abnormal accumulation of gallium in the bilateral hilar lymph nodes, parotid glands, and lacrimal glands on scintigraphy. Examination of bronchoalveolar lavage fluid showed an elevated CD4/CD8 ratio. Transbronchial lung biopsy showed non-caseating granulomas with many epitheloid cells and occasional Langhans giant cells without any necrotic lesion. The tuberculin reaction was negative, and elevation of serum lysozyme and IgG level were seen. These findings fulfilled the clinical criteria for sarcoidosis. Spine MRI demonstrated no abnormality. Studies of short-latency somatosensory evoked potentials showed delayed N13 latency and absent N19 and N28 potentials bilaterally. A nerve conduction study revealed no abnormality. The patient's muscle strength was normal through the entire clinical course. Therefore, we consider that his sensory impairment was caused by peripheral neuropathy, especially in the dorsal root region. Neurosarcoidosis is important for differentiating bell-shaped sensory impairments of all modalities.