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.

Pre-Drilling Prediction Techniques on the High-Temperature High-Pressure Hydrocarbon Reservoirs Offshore Hainan Island,China

Decreasing the risks and geohazards associated with drilling engineering in high-temperature high-pressure(HTHP) geologic settings begins with the implementation of pre-drilling prediction techniques(PPTs). To improve the accuracy of geopressure prediction in HTHP hydrocarbon reservoirs offshore Hainan Island, we made a comprehensive summary of current PPTs to identify existing problems and challenges by analyzing the global distribution of HTHP hydrocarbon reservoirs, the research status of PPTs, and the geologic setting and its HTHP formation mechanism. Our research results indicate that the HTHP formation mechanism in the study area is caused by multiple factors, including rapid loading, diapir intrusions, hydrocarbon generation, and the thermal expansion of pore fluids. Due to this multi-factor interaction, a cloud of HTHP hydrocarbon reservoirs has developed in the Ying-Qiong Basin, but only traditional PPTs have been implemented, based on the assumption of conditions that do not conform to the actual geologic environment, e.g., Bellotti's law and Eaton's law. In this paper, we focus on these issues, identify some challenges and solutions, and call for further PPT research to address the drawbacks of previous works and meet the challenges associated with the deepwater technology gap. In this way, we hope to contribute to the improved accuracy of geopressure prediction prior to drilling and provide support for future HTHP drilling offshore Hainan Island.

Wireless contactless pressure measurement of an LC passive pressure sensor with a novel antenna for high-temperature applications

In this paper, a novel antenna is proposed for high-temperature testing, which can make the high-temperature pressure characteristics of a wireless passive ceramic pressure sensor demonstrated at up to a temperature of 600℃. The design parameters of the antenna are similar to those of the sensor, which will increase the coupling strength between the sensor and testing antenna. The antenna is fabricated in thick film integrated technology, and the properties of the alumina ceramic and silver ensure the feasibility of the antenna in high-temperature environments. The sensor, coupled with the ceramic antenna, is investigated using a high-temperature pressure testing platform. The experimental measurement results show that the pressure signal in a harsh environment can be detected by the frequency diversity of the sensor.

High-Temperature Overpressure Basin Reservoir and Pressure Prediction Model

Yinggehai Basin locates in the northern South China Sea. Since the Cainozoic Era, crust has several strong tension: the basin subsides quickly, the deposition is thick, and the crust is thin. In the central basin, formation pressure coefficient is up to 2.1;Yinggehai Basin is a fomous high-temperature overpressure basin.YinggehaiBasin’s in-depth, especially high-temperature overpressure stratum has numerous large-scale exploration goals. As a result of high-temperature overpressure basin’s perplexing geological conditions and geophysical analysis technical limitations, this field of gas exploration can’t be carried out effectively, which affects the process of gas exploration seriously. A pressure prediction model of the high-temperature overpressure basin in different structural positions is summed up by pressure forecast pattern research in recent years, which can be applied to target wells pre-drilling pressure prediction and post drilling pressure analysis of Yinggehai Basin. The model has small erroneous and high rate of accuracy. The Yinggehai Basin A well drilling is successful in 2010, and gas is discovered in high-temperature overpressure stratum, which proved that reservoir can be found in high-temperature overpressure stratum. It is a great theoretical breakthrough of reservoir knowledge.

Isolated Solid-State Packaging Technology of High-Temperature Pressure Sensor

The principle of miniature isolated solid-state encapsulation technology of high-temperature pressure sensor and the structure of packaging are discussed, including static electricity bonding, stainless steel diaphragm selection and rippled design, laser welding, silicon oil infilling, isolation and other techniques used in sensor packaging, which can affect the performance of the sensor. By adopting stainless steel diaphragm and high-temperature silicon oil as isolation materials, not only the encapsulation of the sensor is as small as 15 mm in diameter and under 1 mA drive, its full range output is 72 mV and zero stability is 0.48% F.S/mon, but also the reliability of the sensor is improved and its application is widely broadened.

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.

Revisiting normal perfusion pressure breakthrough in light of hemorrhage-induced vasospasm

Cerebral arteriovenous malformations(AVMs) have abnormally enlarged arteries and veins prone to spontaneous hemorrhage.Immediately following surgical excision of a cerebral AVM,even normal brain tissue surrounding the lesion is subject to hemorrhage,a phenomenon termed normal perfusion pressure breakthrough(NPPB) syndrome.According to this theory,arteries supplying cerebral AVMs become dilated and lose their capacity to dilate or constrict to autoregulate pressure.Acutely after removal of a cerebral AVM,excessive blood pressure in these arterial feeders can cause normal brain tissue to bleed.However,this theory remains controversial.We present a patient with a cerebral AVM that demonstrated cerebrovascular reactivity and argues against an assumption underlying the theory of NPPB syndrome.

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.

Coefficient of earth pressure at rest for normal,consolidated soils

In this study consecutive consolidated isotropically drained triaxial tests for the coefficient of earth pressure at rest(K_0) were carried out to investigate its rules of evolution as well as its strength characteristics for normal,consolidated saturated silt under high pressure.The tests results indicate that:1) for normal,consolidated saturated silt,K_0 values increase as the consolidation stress increases at high pressure levels,while the nonlinear characteristics of K_0 are inconspicuous compared to cohesive soils;2) the Jaky and Roscoe equations,used to calculate K_0,are only suitable for certain soils,but cannot represent these values for normal, consolidated saturated silt due to the variation in bilinear strength at high pressure;and 3) there are close relations between the nonlinear characteristics of K_0 and the void ratio,measured in the tests.Both share the same functional form while under pressure. Based on our experimental results,we developed an empirical linear model to interpret the rules of nonlinear variation for the coefficient of earth pressure at rest.

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.

Normal Perfusion Pressure Breakthrough Following AVM Resection: A Case Report and Review of the Literature

Objective: To report a patient’s clinical course illustrative of the NPPB mechanism for hyperperfusion-induced injury. Methods: A 65-year-old female presented with a severe headache and was found to have a 6-cm right parietal AVM on imaging. The patient underwent staged, pre-operative embolization and the AVM was surgically resected without intra-operative complication. After the patient emerged from anesthesia she exhibited left hemiplegia and hemispatial neglect. Her systolic blood pressure (SBP) at that time was between 110-120 mmHg. SBP was reduced to 90-100 mmHg and the patient’s symptoms resolved shortly thereafter. The patient’s strict blood pressure goal was relaxed the next morning. However, with her SBP 110-120 mmHg in the ensuing hours, the patient’s left-sided neglect and hemiparesis returned. Her SBP was reduced again to 90-100 mmHg, leading to resolution of her symptoms. Results: This patient’s clinical course supports the NPPB theory of hyperperfusion-induced injury. Despite CT imaging demonstrating no residual AVM following resection, the patient developed neurological deficits in the immediate postoperative period. Aggressive systemic hypotension improved clinical symptoms repeatedly, whereas a brief period of normotension triggered a return of neurological deficits. As a result, there was a direct correlation between fluctuations of neurological status and SBP. This case suggests that the intrinsic autoregulatory capacity was altered in our patient, and that aggressive hypotension was necessary to compensate for diminished autonomic reactivity. Conclusions: This case provides further evidence that NPPB plays a role in hyperperfusion-induced injury following AVM excision and that blood pressure control is vital in managing hyperemic complications following complete resection of cerebral AVMs.

Attenuation-type and failure-type curve models on accumulated pore water pressure in saturated normal consolidated clay

Based on dynamic triaxial test results of saturated soft clay, similarities of variations between accumulated pore water pressure and accumulated deformation were analyzed. The Parr＇s equation on accumulated deformation was modified to create an attenuation-type curve model on accumulated pore water pressure in saturated normal consolidation clay. In this model, dynamic strength was introduced and a new parameter called equivalent dynamic stress level was added. Besides, based on comparative analysis on variations between failure-type and attenuatiun-type curves, a failure-type curve model was created on accumulated pore water pressure in saturated normal consolidation clay. Two models can take cycle number, coupling of static and dynamic deviator stress, and consolidation way into consideration. The models are verified by test results. The correlation coefficients are more than 0.98 for optimization of test results based on the two models, and there is good agreement between the optimized and test curves, which shows that the two models are suitable to predict variations of accumulated pore water pressure under different loading cases and consolidation ways. In order to improve prediction accuracy, it is suggested that loading cases and consolidation ways should be consistent with in-situ conditions when dynamic triaxial tests are used to determine the constants in the models.

Unveiling the silent link:Normal-tension glaucoma's enigmatic bond with cardiac blood flow

This comprehensive review embarks on a captivating journey into the complex relationship between cardiology and normal-tension glaucoma(NTG),a condition that continues to baffle clinicians and researchers alike.NTG,characterized by optic nerve damage and visual field loss despite normal intraocular pressure,has long puzzled clinicians.One emerging perspective suggests that alterations in ocular blood flow,particularly within the optic nerve head,may play a pivotal role in its pathogenesis.While NTG shares commonalities with its high-tension counterpart,its unique pathogenesis and potential ties to cardiovascular health make it a fascinating subject of exploration.It navigates through the complex web of vascular dysregulation,blood pressure and perfusion pressure,neurovascular coupling,and oxidative stress,seeking to uncover the hidden threads that tie the heart and eyes together in NTG.This review explores into the intricate mechanisms connecting cardiovascular factors to NTG,shedding light on how cardiac dynamics can influence ocular health,particularly in cases where intraocular pressure remains within the normal range.NTG's enigmatic nature,often characterized by seemingly contradictory risk factors and clinical profiles,underscores the need for a holistic approach to patient care.Drawing parallels to cardiac health,we examine into the shared vascular terrain connecting the heart and the eyes.Cardiovascular factors,including systemic blood flow,endothelial dysfunction,and microcirculatory anomalies,may exert a profound influence on ocular perfusion,impacting the delicate balance within the optic nerve head.By elucidating the subtle clues and potential associations between cardiology and NTG,this review invites clinicians to consider a broader perspective in their evaluation and management of this elusive condition.As the understanding of these connections evolves,so too may the prospects for early diagnosis and tailored interventions,ultimately enhancing the quality of life for those living with NTG.

Measurement of Episcleral Venous Pressure in Normal Chinese People

<正> Purpose: To measure episcleral venous pressure (EVP) in normal Chinese people. Methods: EVP was measured in 110 eyes of 74 subjects distributed in seven age groups from 10 to 80 years using episcleral venomanometer (EV-310). The differences in EVP values were analyzed with age and either eye.Results: EVP values of the 110 eyes appeared as normal distribution. The value x±SD was (9. 11±1. 22) mmHg, and the 95% normal value range was 6. 73 mmHg ~ 11. 50 mmHg. No statistically significant difference of EVP was found in the seven age groups. And there was no statistically significant difference of EVP between the right and left eyes. Conclusions: The value x ?SD of EVP in Chinese normal eyes is 9. 11 mmHg±1.22 mmHg. The normal value of EVP does not vary with age and either eye. Eye Science 2000; 16: 172- 175.

What is ＂normal＂ intraoperative blood pressure and do deviations from it really affect postoperative outcome？

In our clinical practice, we are accustomed to dealing with perioperative hemodynamic and blood pressure changes on a daily basis. Intraoperative blood pressure variations outside of the accepted ＂normal＂ physiologic ranges are in fact very common.

Resection of Multiple Neurinomas of the Cauda Equina Improves Normal Pressure Hydrocephalus

Normal pressure hydrocephalus (NPH) is a treatable neurological condition characterized by dementia, gait disturbances, and urinary incontinence. This case study aimed to evaluate the effectiveness of surgical intervention in treating NPH associated with spinal cord tumors. A patient suffering with NPH underwent a spinal tap procedure and surgical resectioning of three neurinomas on the cauda equina. The patient exhibited marked improvement in neurological and motor symptoms related to NPH following surgical intervention. These findings suggest that surgical resectioning of neurinomas is an effective intervention for treating NPH associated with spinal cord tumors.

Normal Pressure Hydrocephalus: A Simple Hypothesis

Normal pressure hydrocephalus is a devious phenomenon. It is a disease that is difficult to diagnose and difficult to treat, the only treatment being a ventriculo-peritoneal shunt, though good shunting results rarely pass a 70% level of effectiveness. We need to understand its pathophysiology better before things will improve. Although some colleagues know it as a possible “reversible dementia” others hardly know about its existence. Solutions would also have value for the general understanding of hydrocephalus of other types. Many theories have been published recently in the search for the missing pieces in this puzzle and I feel that my own postulations could turn out to be useful. After years of diagnosing and operating on hydrocephalus patients I propose that: 1) There is reason to believe that patients with the Apoprotein E3/3 genotype and a high head size percentile are particularly vulnerable to developing idiopathic normal pressure hydrocephalus (iNPH). 2) The classical theory that the arachnoid granulations (AG) transport cerebrospinal fluid (CSF) into the venous circulation is wrong. I postulate, that the AG essentially are sensors, registering the pressure differences between the CSF in the subarachnoidal space at the top of the skull and the venous pressure in the sagittal sinus. The AG’s endothelium produces nitric oxide (NO) as a messenger that is received by the vagus nerve at the jugular foramen. 3) The disease has its fundamental pathology in the subpial space in the large cisternas and along the large vessels under the brain. Here the intravenous absorption of cerebrospinal fluid (CSF) takes place. Cerebrospinal fluid is transported into the subpial venules and veins, driven by the pulse pressure of the subpial arteries. Morphological changes in the pial/subpial anatomy explain the existence of acquired normal pressure hydrocephalus (aNPH).

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.

Relationship between cardiovascular risk factors and traditional Chinese constitution in subjects with high-normal blood pressure

Objective: We explored the relationship between traditional Chinese constitution and risk factors for cardiovascular disease in subjects with high-normal blood pressure (BP). Methods: The traditional Chinese constitution of 80 subjects with high-normal BP was judged by questionnaires and interviews. Measurements of cardiovascular and metabolic health in- cluded BP, body weight, body mass index (BMI), low-density lipoprotein cholesterol (LDL-C), 2-hour oral glucose tolerance test (OGTT2h), and waist cir- cumference. Statistical relationships between cardiovascular disease risk factors and specific Chinese constitution were evaluated by univariate and multivariate analyses. Results: Ping He, Tan Shi, and Yin Xu were the dominant constitutions in subjects with high-normal blood pressure. There were significant differences in weight, LDL-C, BMI, OGTT2h, and waist circumference between Tan Shi and Ping He (P P < 0.05), and weight, BMI, waist circumference, SBP, and LDL-C between Tan Shi and Yin Xu constitutions (P < 0.01). Logistic regression found a strong association between the Tan Shi constitution and LDL-C in subjects with high-normal blood pressure. Conclusion: Ping He, Tan Shi, and Yin Xu are the principle traditional Chinese constitutions in subject with high-normal blood pressure. The Tan Shi constitution is associated with multiple risk factors for cardiovascular disease (LDL-C, BMI, body weight, and waist circumference), while OGTT2h is closely related to the Yin Xu constitution.

Sediment Compaction and Pore Pressure Prediction in Deepwater Basin of the South China Sea: Estimation from ODP and IODP Drilling Well Data

Overpressure in deepwater basins not only causes serious soft sediment deformation, but also significantly affects the safety of drilling operations. Therefore, prediction of overpressure in sediments has become an important task in deepwater oil exploration and development. In this study, we analyze the drilling data from ODP Leg 184 Sites 1144, 1146, and 1148, and IODP Leg 349 Sites U1431, U1432, U1433, and U1435 to study the sediment compaction and controls in the northern South China Sea. Sedimentation rate, sediment content, distribution area, and buried depth are the factors that influence sediment compaction in the deepwater basin of the South China Sea. Among these factors, the sediment content is the most important. The fitted normal compacted coefficients and mudline porosity for an interval of 50 m shows disciplinary variation versus depth. The pore pressure predicted from different fitted results shows varying overpressure situations. The normal compaction trend from Site 1144 reflects the porosity variation trend in stable deposition basins in the northern South China Sea. The predicted pore pressure shows overpressure at Site 1144, which is attributed to compaction disequilibrium. Nevertheless, the mixed lithology column may influence the predicted overpressure at Site 1148, which is responsible for the confusing result. Above all, we find that sediment compaction should serve as a proxy for pore pressure in the deepwater basin of the South China Sea.