Current research of idiopathic normal pressure hydrocephalus:Pathogenesis,diagnosis and treatment

Idiopathic normal pressure hydrocephalus(iNPH)is caused by impaired cerebrospinal fluid absorption in the elderly;it is a surgically treatable form of dementia.Gait disturbance,dementia,and urinary incontinence are the triad of signs for iNPH.In addition to these clinical findings,imaging studies show characteristic ventricular enlargement.High Evans Index and‘disproportionately enlarged subarachnoid hydrocephalus’are other well-known imaging findings of iNPH.If the tap test shows improved symptoms,shunt surgery is performed.The disease was first described by Hakim and Adams in 1965,followed by the publication of the first,second,and third editions of the guidelines in 2004,2012,and 2020,respectively.Recent studies signal the glymphatic system and classical cerebrospinal fluid(CSF)absorption from the dural lymphatics as aetiological mechanisms of CSF retention.Research is also underway on imaging test and biomarker developments for more precise diagnosis,shunting technique options with fewer sequelae and complications,and the influence of genetics.Particularly,the newly introduced‘suspected iNPH’in the third edition of the guidelines may be useful for earlier diagnosis.However,less well-studied areas remain,such as pharmacotherapy in non-operative indications and neurological findings other than the triadic signs.This review briefly presents previous research on these and future issues.

Decomposition of CFC and Halon waste gases in normal-pressure plasma reactors

The normal pressure decomposition of CF 2Cl 2 and CF 2ClBr in air by non equilibrium plasma was studied. The pressure of CF 2Cl 2 and CF 2ClBr was 2.67×10 3Pa, added the dry air to 1.01×10 5 Pa, discharged by corona or DBD, 11.5% of CF 2ClBr was decomposed by corona after 120s discharge, more than 85% of CF 2Cl 2 and 95% of CF 2ClBr were decomposed by DBD after 10s discharge respectively. The main products were CF 2O, Cl 2 and Br 2.

Influence of Transverse Normal Pressure on Deformation Behavior of Sheet Metal

To investigate the influence of magnitude and distribution of the transverse normal pressure on deformation behavior of sheet metal,viscous pressure bulge test (VPB) of overlapping sheet metals is proposed,where the overlapped sheet metal is deformed under the dual-sided normal pressure provided by viscous medium and the overlapping sheet.The transverse normal pressure loading features provided by overlapping sheet metals are first simulated by DEFORM-2D.It shows that the magnitude and space distribution of transverse normal pressure are dependent on strain hardening exponent n-,strength coefficient K-and thickness t-values of the overlapping sheet metal.Based on the stress,deviator stress and strain distribution resulted from the finite element simulation,it indicated that the uniform transverse normal pressure has no effect on deviator stress,the figure and strain distribution of bulge specimens have no change.The non-uniform transverse normal pressure can remarkably change the figure and metal flow of specimens,and the formability of sheet metal can be improved by controlling the transverse normal pressure distribution.

Boundary normal pressure-based electrical conductivity reconstruction for magneto–acoustic tomography with magnetic induction

As a kind of multi-physics imaging approach integrating the advantages of electrical impedance tomography and ul- trasound imaging with the improved spatial resolution and image contrast, magneto-acoustic tomography with magnetic induction （MAT-MI） is demonstrated to have the capability of electrical impedance contrast imaging for biological tissues with conductivity differences. By being detected with a strong directional transducer, abrupt pressure change is proved to be generated by the gradient of the induced Lorentz force along the force direction at conductivity boundary. A simplified boundary normal pressure （BNP）-based conductivity reconstruction algorithm is proposed and the formula for conductivity distribution inside the object with the clear physical meaning of pressure derivative, is derived. Numerical simulations of acoustic pressure and conductivity reconstruction are conducted based on a 2-layer eccentric cylindrical phantom model using Hilbert transform. The reconstructed two-dimensional conductivity images accord well with the model, thus success- fully making up the deficiency of only imaging conductivity boundary in traditional MAT-MI. The proposed method is also demonstrated to have a spatial resolution of one wavelength. This study provides a new method of reconstructing accurate electrical conductivity and suggests the potential applications of MAT-MI in imaging biological tissues with conductivity difference.

Research on Pore Pressure-Depth Characteristics in Normal Pressure Reservoir, Bohai Sea Oilfield

In normal pressure of reservoir, formation pressure and depth can not fully reflect the linear relationship between the formation pressure with depth, the change rule of reservoir measured formation pressure and often reduced pressure, understanding unclear cause fluid properties. By introducing basic principles of hydrostatics. The relationship between pressure coefficient and mathematical depth is discussed by mathematical induction analysis of measured pressure data of nearly 50 normal pressure reservoirs in Bohai Oilfield. The results show that the reservoir pressure data is linearly distributed with depth, and the pressure coefficient is inversely proportional to depth. When the depth becomes shallower, the pressure coefficient increases and approaches the reservoir level. As the depth increases, the pressure coefficient decreases and approaches the hydrostatic pressure coefficient infinitely. The study can more accurately analyze the reservoir pressure changes, which is helpful to study the oil and water distribution, reservoir connectivity and fluid properties of atmospheric pressure reservoirs.

SEQUENTIAL INTRAOCULAR PRESSURE MEASUREMENTS IN SUSPECTED OPEN-ANGLE GLAUCOMA

Objective To evaluate the variations of intraocular pressure （lOP） in suspected open-angle glaucoma （OAG） patients. Methods The variations of lOP were measured in 216 eyes of suspected OAG patients at 4-hour intervals for 48 h. Based on the results of the serial lOP measurements, optic disc changed and visual field defected, the patients were diagnosed as primary OAG （ POAG ）, normal tension glaucoma （NTG）, ocular hypertension （ OHT） , or physiologic cup （PC）. Results After the serial lOP measurements, 16. 7% of the suspected OAG patients were diagnosed as POAG, 32. 4% as NTG, 24. 5% as OHT, and 26. 4% as PC. The highest percentages of the POAG group had peak lOP at 8 AM （19. 4% ） and their trough lOP at 10 PM （27. 8% ） ; the NTG group had peak lOP at 12 AM （18. 6% ） and their trough lOP at 12 PM （22. 9% ） ; the OHT group had peak lOP at 4 AM （22. 6% ） and their trough lOP at 10 PM （26. 4% ） ; and the PC group had peak lOP at 4 AM （ 21. 1% ） and their trough lOP at 12 PM （ 21. 1% ）. The percentages of peak lOP outside clinic （ 8 AM - 4 PM） in the POAG, NTG, OHT and PC groups were 55. 6%, 50. 0%, 58. 4% and 45. 7%, respectively. The mean magnitude of variance was 5. 1 - 6. 7 mmHg in those suspected OAG patients. There was a strong positive correlation in lOP between both eyes at each time point of measurement and the variation curves of the right and left eyes had parallel profiles in those suspected OAG patients. Conclusion Serial measurement of lOP is still needed, in order not to miss the peak and the trough lOP readings in suspected OAG patients, which helps in better management of glaucoma.

A new extraction process of refractory gold arsenosulfide concentrates

A new hydrometallurgical process for the refractory gold arsenosulfideconcentrates under normal temperature and pressure was presented. The experimental results of arefractory gold concentrate show that the total consumption of NaOH in alkaline leaching is only 40%of those theoretically calculated under the conditions of full oxidization at the same oxidation ofarsenic to ar-senate and sulfur to sulfate. After alkaline leaching, cyanidation and adsorptionwere carried out for 24 h. The dissolution of gold by NaCN is increased to 95.3% from 12.8% beforepretreatment, and meanwhile 99.3% of the adsorption of gold by activated charcoal. The consumptionof NaCN for one ton ore is 10 kg, which is 1.2 times less than that before pretreatment. As it iscarried out under normal temperature and pressure, the investment of installations is alsodecreased.

Experimental Study on Pull-out Behavior of Different Geotextiles

The pullout testing of geosynthetics is essential for studying interface interaction in the soil-reinforcement system. In this paper, a new method for testing interface properties of geotextiles is proposed. The interface frictional characters of two kinds of geotextiles (woven and needle-punched nonwoven) are investigated through pullout test. Nonwoven specimen has more wide variety of displacement along length than that of woven under the same pressure because of their different extensibility. The greater the elongation and deformation of specimens, the more evident the variations of displacement along reinforcement from front to pullout end. The greater the normal pressure, the smaller the displacement of every position along length with the same pullout load. The study focuses on the effects of the tensile modulus and the difference of pullout response between woven and nonwoven geotextiles.

Comparison of corneal biomechanical properties in normal tension glaucoma patients with different visual field progression speed

AIM：To compare the corneal biomechanical properties difference by ocular response analyzer（ORA） in normal tension glaucoma（NTG） patients with different visual field（VF） progression speed. METHODS：NTG patients with well-controlled Goldmann applanation tonometer（GAT） who routinely consulted Kitasato University Hospital Glaucoma Department between January 2010 and February 2014 were enrolled.GAT and ORA parameters including corneal compensated intraocular pressure（lOPcc）,Goldmann estimated intraocular pressure（lOPg）,corneal hysteresis（CH）,corneal resistance factor（CRF） were recorded.VF was tested by Swedish interactive threshold algorithm（SITA）-standard 30-2 fields.All patients underwent VF measurement regularly and GAT did not exceed 15 mm Hg at any time during the 3y follow up.Patients were divided into four groups according to VF change over 3y,and ORA findings were compared between the upper 25th percentile group（slow progression group） and the lower 25th percentile group（rapid progression group）.RESULTS：Eighty-two eyes of 56 patients were studied.There were 21 eyes（21 patients） each in rapid and slow progression groups respectively.GAT,lOPcc,lOPg,CH,CRF were 12.1＋1.4 mm Hg,15.8±1.8 mm Hg,12.8±2.0 mm Hg,8.4±1.1 mm Hg,7.9±1.3 mm Hg respectively in rapid progression group and 11.5±1.3 mm Hg,13.5±2.1 mm Hg,11.2±1.6 mm Hg,9.3±1.1 mm Hg,8.2±0.9 mm Hg respectively in slow progression group（P=0.214,〈0.001,0.007,0.017,0.413,respectively）.In bivariate correlation analysis,lOPcc,lOPcc-GAT and CH were significant correlated with m△MD（r =-0.292,-0.312,0.228 respectively,P =0.008,0.004,0.039 respectively）.CONCLUSION：Relatively rapid VF progression occurred in NTG patients whose lOPcc are rather high,CH are rather low and the difference between lOPcc and GAT are relatively large.Higher lOPcc and lower CH are associated with VF progression in NTG patients.This study suggests that GAT measures might underestimate the IOP in such patients.

Markers for neural degeneration and regeneration:novel highly sensitive methods for the measurement of thrombin and activated protein C in human cerebrospinal fluid

Inflammation and coagulation are tightly interconnected in the pathophysiology of neuronal diseases.Thrombin,a pro-coagulant serine protease is associated with neurodegeneration and its indirect inhibitor,activated protein C(aPC),is considered neuroprotective.While levels of thrombin and aPC activity are readily measured in the blood,similar assays in the cerebrospinal fluid(CSF)have not been described.The aim of this study was to establish a specific and sensitive enzymatic assay to measure both thrombin and aPC activity in the CSF.CSF was collected from 14 patients with suspected normal pressure hydrocephalus served as a control group,while seven patients with central nervous system infections served as an acute neuro-inflammatory study group and one sample of CSF following traumatic lumbar puncture served as a positive control.Thrombin and aPC activities were measured by fluorescence released by specific proteolytic cleavage in the presence of endopeptidase and amino-peptidase inhibitors to ensure specificity.Specificity of the method was verified by thrombin and serine-protease inhibitors N-alpha-((2-naphthylsulfinyl)glycyl)-DL-p-amidinophenylalanylpiperidine and phenylmethanesulfonyl fluoride.Inhibition of thrombin activity by CSF samples and levels of specific thrombin inhibitors were also assessed.Thrombin and aPC activities were reliably measured and were significantly higher in the CSF of patients with central nervous system infections compared to normal pressure hydrocephalus controls,suggesting the involvement of these factors in neuro-inflammation.CSF thrombin activity levels in the presence of known thrombin concentration were high in patients with central nervous system infections,and low in normal pressure hydrocephalus patients.Quantification of endogenous thrombin inhibitors protease nexin 1,amyloid precursor protein and anti-thrombin III in CSF by western blot indicated a significant elevation of amyloid precursor protein in infectious CSF.In conclusion,this study describes a novel and sensitive assay aimed at the detection of thrombin and aPC activity in CSF.This method may be useful for measuring these factors that reflect degenerative and protective influences of coagulation on neurological disorders.The study procedure was approved by the Ethics Committee of the Chaim Sheba Medical Center(approval No.4245-17-SMC)on October 18,2018.

Nonlinear Out-of-Plane Mechanical Behaviours of Rectangular Woven Composite Flexible Skin Under Uniform Normal Pressure

This paper seeks to investigate nonlinear out-of-plane mechanical behaviours of woven composite flexible skin(WCFS)through experimental and theoretical methods.Firstly,quasi-static experiments are carried out on rectangular WCFSs with different aspect ratios under uniform normal pressure to measure out-of-plane deformation and failure loads.Afterwards,a new three-parameter geometric model is presented to describe 3D geometry of pressurized WCFS,and thus,a nonlinear mechanical model is deduced for depicting the relationship between pressure and out-of-plane displacement.The application of the aforementioned models for experimental results shows that the new models have adequately and logically depicted deformation geometry and nonlinear mechanical characteristics.

Hakim-Adams syndrome secondary to syphilis

Normal pressure hydrocephalus (NPH) secondary to syphilis is an atypical form of neurosyphilis with an unusual clinical presentation and uncommon neuroimaging findings. A case of Syndrome de Hakim-Adams occurring in a 79-year-old male was admitted for investigation of a dementia syndrome. The patient presented with clinical features and neuroimaging compatible with NPH. Syphilis serology was reactive and compatible with active disease. The patient was treated with crystalline penicillin (4 million units every 4 hours for 21 days) and was assessed again after three months, when his cognition and gait had improved and the urinary incontinence had resolved. According to this information, we describe a case of syphilis mimicking normal pressure hydrocephalus, making clear the importance of the investigation of sexually transmitted diseases in the differential diagnosis of dementia, even in patients without established risk supposedly.

Management of Idiopathic Chronic Hydrocephalus of the Adult in Guinea: A Prospective Study in 16 Patients

Object: Incidence of Idiopathic chronic hydrocephalus of the adult (ICHA) is increasing in Guinea due to the aging of the population. The goal of this study was to describe its epidemiology, clinical presentation, and surgical outcome in a low-resource medical environment. Method: Sixteen patients operated for a probable ICHA were prospectively studied according to a uniform protocol from June 2019 to December 2020. On computerized tomography, all operated patients had a clinical triad of gait disturbance, incontinence, dementia associated with ventriculomegaly, and transependymal edema. In addition, all patients underwent a single lumbar tap, improved clinically, and were subsequently offered a shunt consisting of a simple catheter in 37.5% and a non-adjustable high-pressure valve in 62.5%. Result: The mean age was 68.31 ± 10.4 (range 49 - 89). The sex ratio H/F was 1.67/1. Clinically, the most frequent comorbidity was a combination of hypertension and diabetes in 56.5% of cases. The mean time to diagnosis was 8.31 ± 2.75 months (range 3 - 14). The immediate postoperative mortality was 12.5% from a status epilepticus and pulmonary sepsis. In addition, we observed 2 cases of chronic subdural hematoma (12.5%) and 2 cases of shunt dysfunction (12.5%) in the first three months. The functional outcome was good in 23% of patients at one month (N = 13), 50% at three months (N = 10), and 87.5% at six months (N = 8). Conclusion: In carefully selected cases, the surgical outcome of ICHA in Guinea is comparable to high-income countries. Efforts need to be put in helping patients get covered with universal insurance and generally promote Neurosurgery in the country to improve the quality of care.

Analysis of related factors affecting prognosis of shunt surgery in patients with secondary normal pressure hy- drocephalus

Objective： The management of se- condary normal pressure hydrocephalus （sNPH） is controversial. Many factors may affect the surgery effect. The purpose of this study was to identify the possible fac- tors influencing prognosis and provide theoretical basis for clinical treatment of sNPH. Methods： A retrospective study was carried out to investigate the results of 31 patients with sNPH who under- went ventriculoperitoneal shunt surgery from January 2007 to December 2011. We processed the potential influencing factors by univariate analysis and the result further by mul- tivariate logistic regression analysis. Results： Factors including age, disease duration and Glasgow coma scale （GCS） score before surgery significantly influenced the prognosis of sNPH （P〈0.05）. Further logistic regression analysis showed that all the three factors are independent influencing factors. Conclusion： Age, disease duration and GCS score before surgery have positive predictive value in estimating favorable response to surgical treatment for sNPH.

Fractal-like Kinetic Characteristics of Coalbed Methane Hydrate Dissociation at Normal Pressure

Surface modality of coalbed methane hydrate and fractal-like kinetic characteristics of the hydrate dissociation at normal pressure have been studied by using fractal geometry theory. The results show that the surface modality of coalbed methane hydrate has fractal characteristic, and the dissociation kinetics of coalbed methane hydrate is fractal-like. Moreover, a new kinetic model for coalbed methane hydrate dissociation was proposed, and its reliability was validated.

Carbon dots/Bi_(2)WO_(6) composite with compensatory photo-electronic effect for overall water photo-splitting at normal pressure

Overall water photo-splitting is a prospective ideal pathway to produce ultra-clean H_(2) energy by semiconductors.However,the band structure of many semiconductors cannot satisfy the requirement of H_(2) and O_(2) production at the same time.Herein,we illustrate that carbon dots(CDs)/Bi_(2)WO_(6) photocatalyst with compensatory photo-electronic effect has enhanced activity for overall water photo-splitting without any sacrificial agent.In this complex photocatalytic system,the photo-potential provided by CDs makes the CDs/Bi2WO6(C-BWO)composite could satisfy the band structure conditions for overall water photo-splitting.The C-BWO composite(3 wt%CDs content)exhibits optimized hydrogen evolution(oxygen evolution)of 0.28μmol/h(0.12μmol/h)with an approximate 2:1(H_(2):O_(2))stoichiometry at normal pressure.We further employed the in-situ transient photovoltage(TPV)technique to study the photoelectron extraction and the interface charge transfer kinetics of this composite catalyst.

Cognitive Impairment in Idiopathic Normal Pressure Hydrocephalus

Idiopathic normal pressure hydrocephalus(iNPH)is a significant cause of the severe cognitive decline in the elderly population.There is no cure for iNPH,but cognitive symptoms can be partially alleviated through cerebrospinal fluid(CSF)diversion.In the early stages of iNPH,cognitive deficits occur primarily in the executive functions and working memory supported by frontostriatal circuits.As the disease progresses,cognition declines continuously and globally,leading to poor quality of life and daily functioning.In this review,we present recent advances in understanding the neurobiological mechanisms of cognitive impairment in iNPH,focusing on(1)abnormal CSF dynamics,(2)dysfunction of frontostriatal and entorhinal-hippocampal circuits and the default mode network,(3)abnormal neuromodulation,and(4)the presence of amyloid-βand tau pathologies.

Cerebrospinal fluid biomarkers in idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is characterized by abnormal cerebrospinal fluid (CSF) flow and consequent cerebral ventricular enlargement due to imbalance of CSF production and absorption. The typical triad symptoms, namely cognitive decline, gait disturbance, and urinary incontinence, are thought to be caused by disruption of CSF circulation. However, some patients may still experience symptomatic progression after functional shunting, suggesting that iNPH is far more complicated than a simple disorder of CSF circulation. Moreover, the diagnostic workup of iNPH can be challenging due to symptomatic and neuroimaging overlaps with other neurological disorders, such as Alzheimer's disease. Furthermore, accumulating studies indicate that the pathogenesis of iNPH might relate to multiple mechanisms, including abnormalities of brain development, brain extracellular matrix, synaptic function, blood flow, and cerebral metabolism. Therefore, iNPH is not an isolated entity in occurrence and development. Nevertheless, different pathogeneses may result in protein content changes in CSF, and the biomarkers in CSF may reflect the possible mechanisms involving the etiology of iNPH and are potentially useful in assisting the diagnosis and treatment selection. In this review, we summarize the main findings of CSF biomarkers and aim to outline a possible synthetic profile in assisting iNPH diagnosis and therapeutic options.

Radiological biomarkers of idiopathic normal pressure hydrocephalus:new approaches for detecting concomitant Alzheimer’s disease and predicting prognosis

Idiopathic normal pressure hydrocephalus(iNPH)is a clinical syndrome characterized by cognitive decline,gait disturbance,and urinary incontinence.As iNPH often occurs in elderly individuals prone tomany types of comorbidity,a differential diagnosis with other neurodegenerative diseases is crucial,especially Alzheimer’s disease(AD).A growing body of published work provides evidence of radiological methods,including multimodal magnetic resonance imaging and positron emission tomography,which may help noninvasively differentiate iNPH from AD or reveal concurrent AD pathology in vivo.Imaging methods detecting morphological changes,white matter microstructural changes,cerebrospinal fluid circulation,and molecular imaging have been widely applied in iNPH patients.Here,we review radiological biomarkers using different methods in evaluating iNPH pathophysiology and differentiating or detecting concomitant AD,to noninvasively predict the possible outcome postshunt and select candidates for shunt surgery.

In-situ transient photovoltage study on interface electron transfer regulation of carbon dots/NiCo_(2)O_(4) photocatalyst for the enhanced overall water splitting activity

Photocatalytic hydrogen production by overall water solar-splitting is a prospective strategy to solve energy crisis.However,the rapid recombination of photogenerated electron–hole pairs deeply restricts photocatalytic activity of catalysts.Here,the in-situ transient photovoltage(TPV)technique was developed to investigate the interfacial photogenerated carrier extraction,photogenerated carrier recombination and the interfacial electron delivery kinetics of the photocatalyst.The carbon dots/NiCo_(2)O_(4)(CDs/NiCo_(2)O_(4))composite shows weakened recombination rate of photogenerated carriers due to charge storage of CDs,which enhances the photocatalytic water decomposition activity without any scavenger.CDs can accelerate the interface electron extraction about 0.09 ms,while the maximum electron storage time by CDs is up to 0.7 ms.The optimal CDs/NiCo_(2)O_(4)composite(5 wt.%CDs)displays the hydrogen production of 62µmol·h^(−1)·g^(−1) and oxygen production of 29µmol·h^(−1)·g^(−1) at normal atmosphere,which is about 4 times greater than that of pristine NiCo_(2)O_(4).This work provides sufficient evidence on the charge storage of CDs and the interfacial charge kinetics of photocatalysts on the basis of in-situ TPV tests.