High MPI Research Articles

Transformer for low concentration image denoising in magnetic particle imaging.

Objective.Magnetic particle imaging (MPI) is an emerging tracer-basedin vivoimaging technology. The use of MPI at low superparamagnetic iron oxide nanoparticle concentrations has the potential to be a promising area of clinical application due to the inherent safety for humans. However, low tracer concentrations reduce the signal-to-noise ratio of the magnetization signal, leading to severe noise artifacts in the reconstructed MPI images. Hardware improvements have high complexity, while traditional methods lack robustness to different noise levels, making it difficult to improve the quality of low concentration MPI images.Approach.Here, we propose a novel deep learning method for MPI image denoising and quality enhancing based on a sparse lightweight transformer model. The proposed residual-local transformer structure reduces model complexity to avoid overfitting, in which an information retention block facilitates feature extraction capabilities for the image details. Besides, we design a noisy concentration dataset to train our model. Then, we evaluate our method with both simulated and real MPI image data.Main results.Simulation experiment results show that our method can achieve the best performance compared with the existing deep learning methods for MPI image denoising. More importantly, our method is effectively performed on the real MPI image of samples with an Fe concentration down to 67μgFeml-1.Significance.Our method provides great potential for obtaining high quality MPI images at low concentrations.

High Performance MPI over the Slingshot Interconnect

High Performance MPI over the Slingshot Interconnect

Dietary polyphosphate has a greater effect on renal damage and FGF23 secretion than dietary monophosphate.

Phosphate (Pi)-containing food additives are used in several forms. Polyphosphate (PPi) salt has more harmful effects than monophosphate (MPi) salt on bone physiology and renal function. This study aimed to analyze the levels of parathyroid hormone PTH and fibroblast growth factor 23 (FGF23) and the expression of renal / intestinal Pi transport-related molecules in mice fed with an MPi or PPi diet. There were no significant differences in plasma Pi concentration and fecal Pi excretion levels between mice fed with the high-MPi and PPi diet. However, more severe tubular dilatation, interstitial fibrosis, and calcification were observed in the kidneys of mice fed with the high PPi diet versus the MPi diet. Furthermore, there was a significant increase in serum FGF23 levels and a decrease in renal phosphate transporter protein expression in mice fed with the PPi diet versus the MPi diet. Furthermore, the high MPi diet was associated with significantly suppressed expression and activity of intestinal alkaline phosphatase protein. In summary, PPi has a more severe effect on renal damage than MPi, as well as induces more FGF23 secretion. Excess FGF23 may be more involved in inflammation, fibrosis, and calcification in the kidney. J. Med. Invest. 69 : 173-179, August, 2022.

Reconfigurable switches for high performance and flexible MPI collectives

AbstractThere has been much effort in offloading MPI collective operations into hardware. But while NIC‐based collective acceleration is well‐studied, offloading their processing into the switching fabric, despite numerous advantages, has been much more limited. A major problem with fixed logic implementations is that either only a fraction of the possible collective communication is accelerated or that logic is wasted in the applications that do not need a particular capability. Using reconfigurable logic has numerous advantages: exactly the required operations can be implemented; the level of desired performance can be specified; and new, possibly complex, operations can be defined and implemented. We have designed an in‐switch collective accelerator, MPI‐FPGA, and demonstrated its use with seven MPI collectives and over a set of benchmarks and proxy applications (MiniApps). The accelerator uses a novel two‐level switch design containing fully pipelined vectorized aggregation logic units. Essential to this work is providing support for sub‐communicator collectives that enables communicators of arbitrary shape, and that is scalable to large systems. A streaming interface improves the performance for long messages. While this reconfigurable design is generally applicable, we prototype it with an FPGA‐centric cluster. A sample MPI‐FPGA design in a direct network achieves considerable speedups over conventional clusters in the most likely scenarios. We also present results for indirect networks with reconfigurable high‐radix switches and show that this approach is competitive with SHArP technology for the subset of operations that SHArP supports. MPI‐FPGA is fully integrated into MPICH and is transparent to MPI applications.

TyphicIleal Perforation at Kati Chu-BSS for Diagnostic and Therapeutic Aspects (Mali)

Ileal perforation of typhus origin is a common and serious complication of typhoid fever in tropical environments. It is one of the main causes of morbidity in surgery in Mali. However, it would be preventable if salmonellosis were properly managed upstream, and if our living environments were cleaned up. The purpose of this study is to report on the experience of the Kati UHC General Surgery Department in the management of peritonitis by typhic perforation and to assess its prognosis. Patients and Method: This is a retrospective descriptive study that took place from January 2007 to December 2020 in the General Surgery department of the Hospitalo-University BSS Center of Kati (Mali). We have included patients who have undergone peritonitis with confirmed typhic ileal perforation with laparotomy. The other etiologies of peritonitis by ileal perforation were not retained. Results: In 14 years, we collected 89 cases of peritonitis by typhic ileal perforation. It accounted for 3.14% (89/2829) of surgical procedures, 37.5% (89/1181) of visceral surgical emergencies and 27.6% (89/322) of all acute peritonitis causes combined. There were 70 men against 29 women; the sex ratio was 2.4 with an average age of 25.8 years (extremes 8 years to 65 years). Anastomosis resetions (ileo ileal and ileocolic) predominated in 71.8% of patients. However, the ileo stoma was performed in 5.6%. A significant relationship (p 0.05) was observed between high mortality and MPI score > 26. Morbidity was 39.4% with mortality of 15.7%. The average length of stay in hospital was 12.2 days. Conclusion: Typhoid ileal perforation is common in young male adolescents in visceral surgery. This pathology generates significant morbidity. However with the extension of hand washing after Ebola disease its frequency has dropped.

Independent risk factors for a small placenta and a small-for-gestational-age infant at 35-41weeks of gestation: An association with circulating angiogenesis-related factor levels at 19-31weeks of gestation.

Our aim was to investigate the effects of angiogenesis-related factor levels at 19-25 and 26-31weeks of gestation (WG) on the later occurrence of a small-for-gestational-age (SGA) placenta (small placenta) or an SGA infant delivered at 35-41WG. We measured plasma levels of soluble fms-like tyrosine kinase 1 (sFlt-1) and placental growth factor (PlGF), and the serum level of soluble endoglin (sEng) in 679 pregnant women with blood sampling at both 19-25 and 26-31WG in a prospective study. A small placenta and an SGA infant were defined as <10th percentile, respectively. Multivariate logistic regression analyses were performed using maternal factors, a high mean pulsatility index (high mPI) of the uterine artery in the second trimester, and angiogenesis-related factor levels. Regarding the occurrence of a small placenta, low PlGF at 19-25WG (adjusted odds ratio [95% confidence interval]: 2.4 [1.01-5.7]) and a high mPI (2.5 [1.4-4.3]) were independent risk factors. Moreover, low PlGF at 26-31WG (3.3 [1.5-7.0]) was also an independent risk factor after adjusting for the effect of mPI. Concerning the occurrence of an SGA infant, a high mPI (2.8 [1.6-5.2]) and high sEng at 26-31WG (2.3 [1.2-4.5]) were independent risk factors. Low levels of PlGF at 19-25 and 26-31WG were independent risk factors for a small placenta at ≥35WG; and a high sEng at 26-31WG was an independent risk factor for an SGA infant at ≥35WG.

Primary peritoneal drainage in critically ill patients of perforation peritonitis (an experience of 60 cases)

Background: Objective of the present study was to evaluate applicability of Primary Peritoneal Drainage (PPD) under LA in critically ill patients as pre-laparotomy support when laparotomy under GA could not be done. Also to assess outcome in terms of survival, patients needing definitive surgery and complications associated with the procedure on immediate and follow up basis.Methods: A prospective designed study including 60 critically ill patients admitted and diagnosed as perforation peritonitis were subjected to PPD under LA as per inclusion and exclusion criteria, at GMC Jammu, Jammu and Kashmir, India from November 2013 to October 2015.Results: The average age of patients was 53.43 years (20-80 years) with M:F ration of 7:3. All patients presented in shock with very high ASA, combined and MPI scores. 40 patients died after PPD/laparotomy and 20 patients survived. From amongst survivors, 08 (40%) patients required no further treatment and 12 (60%) survivors required definitive laparotomy and treatment of the cause. Overall mortality was 66.67%, attributed to extraordinary delay in presentation, old age, High ASA and other score.Conclusions: From the present study it was concluded that in adults the procedure did not proved comparable to standard surgical intervention as definite procedure but it did proved to be an effective modality of resuscitation and patient stabilization unlike in NEC of infants; PPD under LA. Overall the procedure is a low cost intervention and provide cheaper alternative to sustain and improvise the status of patient with a possibility of widespread applicability in low resource situations provided interdepartmental support from ICU, Dialysis and CCU is available.

Evaluation of the coronary circulation and calcification in children on regular hemodialysis.

The objective of this study was to evaluate the coronary circulation and calcification in children with end-stage renal disease (ESRD) on hemodialysis. A total of 50 children with ESRD and 50 healthy controls were enrolled in the study. Cardiac functions and coronary blood flow were evaluated with conventional and tissue Doppler echocardiography. Coronary artery calcification (CAC) was evaluated using high-resolution multidetector computed tomography (CT). The hyperemic coronary flow volume (CFV) and coronary flow reserve were significantly lower in the patient group than in the controls, while there was no significant difference in the baseline CFV between the two groups. Hypertension was present in 60% and CAC was observed in 20% of the children in the patient group. CAC was present in 30% of the children in the hypertensive subgroup. The left ventricle myocardial performance index (LV MPI), CAC score, duration of hypertension and level of diastolic blood pressure were independent predictors of the coronary blood flow, and LV MPI, serum parathyroid hormone, duration of dialysis and E'/A' mitral valve were independent predictors of coronary calcification. High diastolic blood pressure, long duration of hypertension, high LV MPI and increased CAC scores are independent risk factors for impaired coronary blood flow in children with ESRD.

Laparoscopic versus Open Omental Patch Repair for Early Presentation of Perforated Peptic Ulcer: Matched Retrospective Cohort Study.

Introduction. The aim of this study was to compare the outcomes between laparoscopic and open omental patch repair (LOPR versus OR) in patients with similar presentation of perforated peptic ulcer (PPU). The secondary aim was to evaluate the outcomes according to the severity of peritonitis. Methods. All patients who underwent omental patch repair at two university-affiliated institutes between January 2010 and December 2014 were reviewed. Matched cohort between LOPR and OR groups was achieved by only including patients that had ulcer perforation <2 cm in size and symptoms occurring <48 hours. Outcome measures were defined in accordance with length of stay (LOS), postoperative complications, and mortality. Results. 148 patients met the predefined inclusion criteria with LOPR performed in 40 patients. Outcome measures consistently support laparoscopic approach but only length of hospital stay (LOS) achieved statistical significance (LOPR 4 days versus OR 5 days, p < 0.01). In a subgroup analysis of patients with MPI score >21, LOPR is also shown to benefit, particularly resulting in significant shorter LOS (4 days versus 11 days, p < 0.01). Conclusion. LOPR offers improved short-term outcomes in patients who present within 48 hours and with perforation size <2 cm. LOPR also proved to be more beneficial in high MPI cases.

Evaluation of the Mannheim’s Peritonitis Index in Predicting Mortality in Patients with Perforative Peritonitis

Aim: To study the applicability of the Mannheim's peritonitis index in predicting mortality in patients with perforative peritonitis. Methods: A total of 50 patients diagnosed as perforative peritonitis based on history, clinical examination, and plain skiagram abdomen erect antero-posterior view were studied. The Mannheim's peritonitis index was calculated at first laparotomy. Results: Overall post-operative mortality rate was 10%. Middle age population (35-55 years) was predominantly affected (48%) with male preponderance (75%). Peptic ulcer perforation was the most common cause of peritonitis. Malignant perforation of hollow viscus accounted for only 4% of cases. Mean MPI Score of survivors was 22.04, and that of non survivors was 33.2. Mortality rate was highest in patients with high MPI Score. Conclusion: Mannheim's peritonitis index is easy to use, with all variables easily available at first laparotomy, with reproducible results and is a reliable predictor of mortality.

Evaluation of the Mannheim's Peritonitis Index in Predicting Mortality in Patients with Perforative Peritonitis

&lt;p&gt;&lt;strong&gt;Aim:&lt;/strong&gt; To study the applicability of the Mannheim's peritonitis index in predicting mortality in patients with perforative peritonitis.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods:&lt;/strong&gt; A total of 50 patients diagnosed as perforative peritonitis based on history, clinical examination, and plain skiagram abdomen erect antero-posterior view were studied. The Mannheim's peritonitis index was calculated at first laparotomy.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results:&lt;/strong&gt; Overall post-operative mortality rate was 10%. Middle age population (35-55 years) was predominantly affected (48%) with male preponderance (75%). Peptic ulcer perforation was the most common cause of peritonitis. Malignant perforation of hollow viscus accounted for only 4% of cases. Mean MPI Score of survivors was 22.04, and that of non survivors was 33.2. Mortality rate was highest in patients with high MPI Score.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusion:&lt;/strong&gt; Mannheim's peritonitis index is easy to use, with all variables easily available at first laparotomy, with reproducible results and is a reliable predictor of mortality.&lt;/p&gt;

Parallel DNS for vortex structure of late stages of flow transition

A new DNS using compact high order scheme and MPI parallel computation has been conducted with 1920 × 241 × 128 grid points for non-linear stages of flow transition. The coherent vortex structure of the late flow transition stages and the mechanism of formation of single vortex ring, multiple vortex rings, and small length scales are discussed. The ring-like vortex formation from the Λ-vortex is the result of the interaction of two pairs of counter-rotating primary and secondary streamwise vortices. The formation of the multiple ring structure follows the first Helmholtz vortex conservation law. A bridge must be formed to link two Λ-vortex legs. The bridge finally develops as a new ring. This process keeps going onto form a multiple ring structure. The U-shaped vortices are part of existing coherent large vortex structure. Actually, the U-shaped vortex, which is a third level vortex, serves as a second neck to supply vorticity to the multiple rings. The multiple ring-like vortex structure is found quite stable and can travel for a long distance. The “hairpin vortex breakdown” does not happen. The small vortices can be found on the bottom of the boundary layer near the wall surface. It is believed that the small vortices are generated by the interaction of higher level vortices with the solid wall, but not by the “vortex breakdown”.

P-126 Diagnosis of Cardiac Amyloidosis with Quantitative Analysis of Myocardial Technetium-99m-Pyrophosphate Scintigraphy

Objective: To determine the correlation of Duke treadmill score with gated SPECT-MPI in patients evaluated for chest pain. Methods: We conducted a retrospective study on 200 consecutive patients referred to our imaging laboratory for evaluation of chest pain by using stress MPI from January to August 2008. DTS was calculated after exercise testing and categorized as low, moderate and high subgroups. Subsequent gated SPECT-MPI was performed and stratified according to severity of perfusion defect. Spearmans rho was applied to determine the correlation. Results: The overall result shows positive linear correlation between DTS and MPI (p 0.001). Out of 200 patients, 136 (68%) had low DTS, 51 (25.5%) had moderate and 13 (6.5%) had high DTS respectively. In low DTS group 129 (95%) patients had low risk MPI and 7 (5%) had intermediate risk MPI. In moderate risk DTS group 25 (49%) had low risk MPI whereas 15 (29.5%) and 11 (21.5%) had intermediate and high risk MPI respectively. In high DTS group all 13 patients had high risk MPI. Conclusion: On the basis of our findings it can be hypothesized that patients with high DTS can be referred for coronary angiography without imaging and patients with low DTS can be followed on medical management. However for definite conclusion diagnostic accuracy need to be determine in further studies.

New techniques for simulating high performance MPI applications on large storage networks

In this paper we present new techniques for simulating high performance MPI applications on large storage networks. Performance analysis of high performance application on large storage networks is a very complex and time-consuming task. However, modelling and studying the behaviour of any application on complex network architectures is crucial to obtain good performance. The goal of this work is to predict both scalability degree and performance of any high computing applications on any network architecture. A very interesting feature of this work is that our approach does not require to modify the application in order to simulate its behaviour. Also, there is no need to modify the simulator code to test different architectures. It can be done just creating a new configuration file. In order to perform those analyses we have used SIMCAN, a simulation tool to analyzing high-performance I/O architectures, developed at University Carlos III de Madrid. To validate this work we have used the BIPS3D application on several hardware-based architectures and on our simulator. The comparative results of those environments are presented to show the accuracy and efficiency of our approach.

A High Performance MPI for Parallel and Distributed Computing

A High Performance MPI for Parallel and Distributed Computing

Viral Hepatitis

Viral Hepatitis

An Ultrahigh Performance MPI Implementation on SGI® ccNUMA Altix® Systems

The SGI Message Passing Toolkit (MPT) software has implemented algorithms that provide extremely high-performance message passing on SGI Altix systems based on the SGI NUMAlinkTM interconnect technology. Using Linux OS infrastructure and SGI XPMEM cross-host memory-mapping software, SGI MPI delivers extremely high MPI performance on shared-memory single host/SMP Altix systems as well as multihost superclusters. This paper outlines the Altix hardware features, OS features, and library software algorithms that have been developed to provide the low-latency and high-bandwidth capabilities. We present high-performance features like direct copy send/receive, collectives, and the ultralow-latency SHMEMTM data transfer library. We include MPI benchmark results, including an MPI ping pong latency that ranges from 1.2 to 2.3 microseconds on a 512-CPU Altix system with 1.5 GHz Intel Itanium 2 Processors.

Myocardial performance index, a Doppler-derived index of global left ventricular function, predicts congestive heart failure in elderly men

There is limited data on echocardiographic and Doppler indices of cardiac function as predictors for congestive heart failure (CHF) in the general population. Myocardial performance index (MPI, also denoted TEI-Doppler index) reflects both left ventricular (LV) systolic and diastolic function. We compared eight different echocardiographic and Doppler indices of cardiac function as predictors of CHF using a population-based cohort of 552 seventy-year-old men without CHF and significant valve disease at baseline (median follow-up time 8.2 years). In a stepwise multivariable Cox proportional-hazard analysis including the different indices of cardiac function, high MPI (above the 90th percentile of MPI [> or =0.91]), abnormal LV wall motion score index and a pseudo-normalized/restrictive E/A-ratio pattern independently predicted future CHF morbidity. After adding traditional CHF risk factors (age, previous myocardial infarction, hypertension, diabetes mellitus, hyperlipidaemia, smoking, LV hypertrophy and body mass index) to the above model, only a high MPI remained a significant predictor (hazard ratio 4.72, 95% CI 1.75-12.76, p=0.002). MPI provides important prognostic information for the risk of future CHF, beyond other measurements of cardiac function and traditional heart failure risk factors in elderly men. MPI seems to be a clinically relevant indicator of cardiac function and may prove to be a valuable tool in assessing the risk of future CHF.

Mandibular two-implant telescopic overdentures.

To stabilize mandibular overdentures in edentulous patients, various connector types which can be attached to between two and four implants placed in the anterior mandible are possible. Treatment using non-rigid telescopic connectors on two interforaminal implants for overdenture stabilization began in 1989. The objective of this study is to investigate soft- and hard-tissue conditions as well as prosthesis function after a period of 10 years. This also involved an evaluation of correlations between radiographic and clinical parameters. Twenty-three subjects with 46 interforaminal implants (ITI solid screw implants, 12 mm in length, 4.1 mm in diameter; 10.4 years in situ, range, 8-12.8 years) were investigated. Modified plaque index (mPI), sulcus fluid flow rate (SFFR), modified sulcus bleeding index (mBI), probing depth (PD), distance from implant crown margin to the coronal border of the peri-implant mucosa (DIM), attachment level (AL), width of keratinized mucosa (KM), Periotest values (PTVs) and prosthesis function were evaluated. In the radiographic evaluation, the distance between implant shoulder and first crestal bone-implant contact (DIB) in mm and the horizontal bone loss (HBL) in mm were measured. The relatively high mPI scores (mean, 0.82; score, 0 in 44.4%; SD, 0.83) did not result in increased SFFR scores (mean, 12; min, 3, max, 38; SD, 7.43) or higher mBI scores (mean, 0.35; score, 0 in 70.8%; SD, 0.59), which was commensurate with healthy peri-implant mucosa. A mean PD value of 2.15 mm (min, 1 mm; max, 5 mm; SD, 0.96) and a mean DIM value of 0.28 mm (min, 0 mm; max, 2 mm; SD, 0.52) were measured. The implants were stable, showing a mean Periotest value of -1.91 (max, 02, min, -6; SD, 1.76). A mean DIB of 3.19+/-0.95 mm (range, 1.3-5.16 mm) and a mean HBL of 1.6+/-1.52 mm (range, 0.28-8.33 mm) were calculated. A correlation was found between DIB and the parameters SFFR (P=0.060), DIM (P=0.042), AL (P=0.050) and especially PTV (P<0.01), leading to the assumption that these clinical parameters may be useful indicators of peri-implant bone loss. The results of the 10-year follow-up examination show that non-rigid telescopic connectors with two interforaminal implants for overdenture stabilization appear to be an efficient and effective long-term treatment modality in severely resorbed edentulous mandibles. Particularly in geriatric patient treatment this concept may provide advantages in terms of handling, cleaning and long-term satisfaction.

Using the Memory Channel Network

Digital has announced and shipped this first-generation, high-performance network for clusters, the Memory Channel for PCI network, and all SMP AlphaServers running Digital Unix support it. Digital has publicly demonstrated Memory Channel-connected systems running Windows/NT. The Memory Channel network does not require functionality beyond the PCI bus specification and works with any system having a PCI I/O slot. Production Memory Channel clusters can be as large as eight nodes (limited only by first-generation hardware) of 12 processors each (96 processors). One such cluster installed at Supercomputing 95 ran clusterwide applications using High Performance Fortran, PVM, and MPI. A four-node, 48 processor Memory Channel cluster, using Oracle Parallel Server, has held the record for TPC-C benchmarks since its introduction in April 1996. The same Memory Channel network used to connect this high-end database configuration also cost-effectively supports configuration of two-node, single-processor clusters. Latency over Memory Channel for a one-way, user-process-to-user-process message is 2.9 microseconds. The processor overhead is less than 150 ns for a 32-byte message. Standard message-passing APIs benefit greatly from this underlying capability.