Background: Her-2/neu, the human epidermal growth factor receptor-2, is an oncogene reported to be excessively expressed in gastric cancer. This over-expression is a criteria for treatment with trastuzumab. An antigen linked to nuclear proliferation is Ki-67, and the level of gastric cancer aggression is reflected in its expression. Objective: To determine the expression of Her-2 and Ki-67 in gastric cancer formalin-fixed paraffin-embedded (FFPE) tissue blocks and their correlation with histological grades at the Uganda Cancer Institute pathology laboratory, with each block representing one gastric cancer case. Methods: A laboratory cross-sectional study was conducted among 75 endoscopic gastric cancer patient cases. Each case was assessed utilizing immunohistochemistry (IHC) for the expression of Her-2 and Ki-67. Spearman correlation coefficient was used to ascertain the expression and its correlation to histological grades. Results: The age range of gastric cancer cases was 26 to 80 years, with a mean age of 54. Poorly differentiated histology (43%) was the most profound. Her-2 over-expression was 20%. High Ki-67 expression was 56%, and the low Ki-67 expression was 7%. Her-2 overexpression correlated significantly with moderate differentiation (rs = 0.336, p = 0.003) and poor differentiation (rs = -0.229, p = 0.048). A significant correlation between moderate differentiation of gastric carcinoma with low intensity of Ki-67 staining was noted (rs = 0.255, p = 0.028). Conclusion: The aggressiveness of gastric cancer may be indicated by the over-expression of Her-2 and a high Ki-67. What This Study Adds: This study provides additional information on the relevance of Her-2 and a high Ki-67 over-expression in diagnosis, prognostic monitoring, and management of gastric cancer in Uganda.
Purpose: Head and Neck squamous cell carcinoma (HNSCC) is the seventh most common cancer in the world. The prognosis of patients with HNSCC remains unsatisfactory, with a 5 -years survival rate of only approximately 50%. In western Uganda, the 1 -year survival rate is only 1%. Programmed cell death ligand 1 (PD -L1) and p16 have been shown to predict the progression of HNSCC lesions, prognosticate survival, reveal new therapeutic targets, and predict response to therapeutic agents. HNSCC patients with positive PD -L1 expression have been reported to benefit from immunotherapy; however, data on PD -L1 expression in HNSCC in Uganda and Africa are still lacking. This study aimed to determine the expression of PD -L1 in HNSCC and its association with p16 expression in Southwestern Uganda. Patients and Methods: We retrospectively studied 165 formalin-fixed paraffin -embedded specimens from the head and neck region with a previous histological diagnosis of squamous cell carcinoma (SCC). The specimens were retrieved from June 2012 to June 2022. Hematoxylin and eosin (H&E) staining was performed to confirm the diagnosis, followed by immunohistochemical (IHC) staining for PD -L1 and p16 using the laboratory developed technique. Results: Of the 165 specimens included in the study, 80% of source patients were male and the majority (51.5%) were older than 60 years. The oral cavity was the predominant site (51.52%). PD -L1 was expressed in 32.1% (95% C.l: 25.4-39.68) of the specimens, whereas p16 was expressed in 16.36% (95% C.l: 11.4-22.9). There was a statistically significant association between PD -L1 and p16 expression. Conclusion: The prevalence of PD -L1 expression in HNSCC in southwestern Uganda is low, implying that a number of patients with HNSCC can benefit from immunotherapy. PD -L1 expression may predict p16 expression and therefore HPV infection in HNSCC.
Purpose: Formalin-fixed tissue biopsies submitted to the Histopathology Laboratory were explored for possible use in the GeneXpert MTB/Rifampicin assay for EPTB diagnosis, therefore this study aimed to determine the diagnostic utility of the GeneXpert MTB/RIF assay in EPTB detection in formalin-fixed paraffin-embedded tissue biopsies using Ziehl-Neelsen (ZN) and Haematoxylin and Eosin (H&E) staining as a composite reference standard. Methods: A total of 89 selected archived formalin-fixed paraffin-embedded tissues with histological features of tuberculosis were included in the study. ZN and H&E staining were performed as a composite reference standard, followed by GeneXpert MTB/RIF assay as diagnostic test. Data were analysed using STATA software version 17.0. Results: Of the 89 specimens enrolled, 55% were male. The Lymph node was the commonest site (64%). 15/89 (16.9%) cases were positive for ZN, 45/89 (50.6%) were positive for H&E and 27/89 (30.3%) were positive for GeneXpert. The overall sensitivity and specificity of GeneXpert were 48.94% (95% CI: 38.55%-59.32%) and 90.48% (95% CI: 84.38%-96.57%), respectively, in lymph node tissues, were 52.94% (95% CI: 39.98%-65.90%) and 82.61% (95% CI: 72.77%-92.45%), respectively, and in Non-Lymph node tissues, were 38.46% (95% CI: 21.61%-55.32%) and 100% (95% CI: 100%-100%), respectively. Conclusion: The GeneXpert MTB/RIF assay is a potential tool for diagnosing EPTB in FFPE tissues and may be used in the development of an algorithm in the histopathology laboratory.
Background: Thyroid nodules are the most common thyroid disease and its incidence has been rising throughout the world. Thus, this study aimed to assess the patterns of fine needle aspiration cytology-diagnosed thyroid nodules among clinically suspected patients.Methods: A prospective cross-sectional study was conducted from April 2021 to March 2022 using 424 study participants who were referred to undergo fine needle aspiration cytology examination and were consecutively included. Moreover, two FNAC smears were prepared and stained using Wright and Giemsa staining solutions and then examined by an experienced licensed pathologist. Multivariate logistic regression was used to determine the association of socio-demographic and clinical variables with nodules. P-value < 0.05 was considered to be statistically significant.Results: The overall magnitude of benign and malignant nodules was 60.4% and 16.5% respectively. Moreover, the magnitude of atypical of undetermined significance or follicular lesion of undetermined significance (AUS/FLUS) and follicular neoplasm or suspicious of follicular neoplasm (FN/SFN) was 3.54% and 1.42% respectively. The magnitude of malignant thyroid nodules was 5.9% for malignant secondary adenocarcinoma, 3.5% for papillary thyroid carcinoma, 2.6% for Non-Hodgkin lymphoma, 2.4% for medullary thyroid carcinoma, 1.4% of an undifferentiated malignant thyroid tumor and 0.7% of Hodgkin lymphoma respectively. Multivariate logistic regression showed that age categories between 0 and 15 years and between 16 and 30 years, and nodule size >2.5cm were significantly associated with malignant thyroid nodules.Conclusion: The magnitude of benign and malignant tumors was 60.4% and 16.5% respectively. Being younger and having nodule size >2.5cm were significantly associated with malignant thyroid nodules. Therefore, fine needle aspiration cytology examination has a crucial role in the diagnosis and management of benign and malignant thyroid nodules.
Purpose: There is a documented association between cervical cancer and metabolic syndrome. In this study, we determined the association between lipids, insulin-like growth factor binding protein-3 (IGFBP-3) and treatment outcomes for cervical lesions at Mbarara Regional Referral Hospital (MRRH) in south western Uganda.Patients and Methods: In this prospective cohort study, we recruited 94 cases and 94 controls at the cervical cancer clinic of MRRH, and followed them for 12 months. Cases were confirmed with cytology and/or histology. With consent, we collected demographic data and measured lipids and IGFBP-3 both at baseline and after 12 months. The lipid profile was measured using a Cobas 6000 Chemistry Analyzer, whereas IGFBP-3 was measured using a MAGLUMI fully automated chemiluminescence immunoassay analyzer. Abnormal values for lipids were defined using WHO recommended cut-offs. IGFBP-3 concentrations were divided into two categories of low concentration (<3.29 g/mL) and raised concentration (>= 3.29 mu g/mL). Statistical analyses were conducted in STATA version 17 using logistic regression analysis. A p-value of <0.05 was taken to be statistically significant.Results: The average (mean +/- SD) age of our participants was 38.7 +/- 8.2 years for controls and 34.5 +/- 7.8 years for cases. The average serum IGFBP-3 concentration was 3.769 +/- 1.098 g/mL among cases with cleared lesions and 3.505 +/- 0.979 mu g/mL among cases whose lesions persisted. A serum IGFBP-3 concentration of less than 3.291 mu g/mL was likely to be associated with clearance of cervical lesions (AOR 1.65, p=0.67), although this was not statistically significant. A serum triglyceride concentration of 35-135 mg/dL was also likely to be associated with clearance of cervical lesions (AOR 2.41, p=0.46), although this was also not statistically significant.Conclusion: Although not statistically significant, reduced serum concentrations of IGFBP-3 and triglyceride may be associated with clearance of cervical lesions. Lipid management may be of benefit in the treatment of cervical lesions.
Introduction: In clinical laboratory, the performance of the hematology analyzer should be checked routinely to ensure the desired quality. Therefore, the aim of the study was to assess the analytical performance of hematology analyzer using sigma metrics.Methods: The study included all daily internal quality control (IQC) data of hematology analyzer prospectively from August to October 2022. Data was collected using record formats by trained laboratory professionals. The sigma values of each CBC parameter were calculated using the formula: Sigma = (TEa - Bias) / CV. The TEa data were adopted from five different guidelines to calculate sigma value of the laboratory based on different specification. The bias of all complete blood count (CBC) parameters was calculated from the laboratory mean of the daily IQC data and the target value of the manufacturer in the insert kit. A coefficient of variations was also calculated using IQC data.Results: The current study found that sigma value of the analyzer varied based on source of TEa. Except HCT out 5 parameters included based on CLIA guideline, except MCV, MCHC, RDW, MPV and Basophil out of 15 parameters included based on EFLM 2022 minimum guideline, except Hb and PLT out of 9 parameters included based on SOTA guideline other parameters meets minimum specification (<3 sigma value). On the other hand, all parameters included in Rilibak and Standards of Spanish guideline achieved minimum specification (>3 sigma value).Conclusion: Sigma values of the CBC parameters have significantly varied depends on the TEa sources. So, it is recommended laboratory to use alternative sigma value based on its preference. Additionally, it is suggested that the laboratory to design local Westgard rules for each parameter based on sigma value.
Pleomorphic adenoma (PA) is a common benign tumor of the salivary glands, but its occurrence in the minor salivary glands of the upper lip is rare. In the a case report of a 24-year-old female with PA of the minor salivary glands in the upper lip, exhibiting unique histological characteristics such as features resembling schwannoma, keratinization, myxolipomatous, oncocytic, and mucinous traits resembling mucoepidermoid carcinoma. The main symptom of this condition is a gradual painless enlargement of the affected area. Histopathological analysis confirmed the diagnosis of PA. This case highlights the importance of public education in recognizing and treating painless masses. Further research is needed to explore PA's histological and molecular characteristics to establish prognostic factors such as the risk of recurrence.
Background: The significance of quality in laboratories necessitates the implementation of comprehensive quality management throughout the entire laboratory process, encompassing the pre-analytical to post-analytical phases. The pre-analytical phase, which plays a crucial role in laboratory services, is particularly significant, as it is responsible for approximately 70% of errors. Enhancing the quality of the pre-analytical phase is essential to ensure the effectiveness of laboratory services and safeguard patient safety. Objective: The objective of this study was to assess errors made in the request format and phlebotomy procedures during the collection of blood samples for hematology laboratory tests between April and June 2019. Methods: A cross-sectional study was carried out at Hawassa University College of Medicine and Health Sciences on 393 samples with their respective request forms. The study employed a systematic sampling technique and utilized well-structured checklists to gather all the necessary data for hematology laboratory tests, including a thorough evaluation of the requested form. Data analysis was performed using the Statistical Package for Social Sciences (SPSS) software version 21. Results: A total of 393 hematological samples from their respective request forms were analyzed in this study. Generally, the request forms did not contain all the necessary information, and each form had at least one error. The study also revealed the occurrence of pre-analytical errors in phlebotomy practice. These errors included prolonged tourniquet application (26.2%), improper identification (22.9%), inadequate cleaning of the vein puncture site (62.8%), unsafe needle removal and blood transfer to test tubes (6.6%), and improper mixing of collected blood samples (41.5%). Conclusion: The findings of this study revealed a substantial occurrence of pre-analytical errors in the hematology laboratory department. Therefore, it is crucial to prioritize the correct execution and utilization of phlebotomy procedures as well as request format to enhance quality assurance in hematology laboratory units.
Infectious diseases are considered a major cause of death globally, accounting for one-third of all deaths. Traditionally, microbiological approaches to diagnose infectious diseases have been labor-intensive and time-consuming; molecular methods significantly improve on these constraints. DNA microarray is a novel and advanced diagnostic test for infectious disease that is designed for specific identification of a wide variety of organisms simultaneously. Microarray has various advanced applications in infectious disease diagnostics, including the 2019 pandemic COVID 19, detection of food-borne infectious agents, and detection of Neisseria meningitidis. The aim of this review is to provide updated application of DNA microarray techniques for the diagnosis of infectious diseases and to explore the development of new DNA microarray methods. In conclusion, DNA microarray techniques are the future rapid and accurate diagnostic tool for infectious disease diagnosis and detection of antimicrobial resistance.
Given the growing impact of antimicrobial resistance, improvements in diagnosis and treatment of the most common outpatient infection, urinary tract infection (UTI), are of great interest to stakeholders. Regulatory authorities have long accepted a microbial threshold of 105 CFU/mL as the standard for diagnosing UTI based on standard urine cultures. However, microbial thresholds considered clinically relevant remain in dispute. The aim of this systematic scoping review is to assess the evidence supporting a threshold of 105 CFU/mL, to review microbial threshold guidelines, and highlight knowledge gaps in the diagnosis of UTI. A total of 36 guidelines containing 144 recommendations were identified with 64% of guidelines (n = 23) and 58% of recommendations (n = 83) published in the last six years (2016-2023). Recommendations have changed over time and across variables including the geographical location of the guideline, urine specimen collection method, patient sex, and category of UTI. Guidelines uniformly agreed with suprapubic needle specimen collection; however, there was no consensus for midstream collected urine samples. Guideline microbial thresholds for clinical UTI diagnosis were higher for women at average risk (105 CFU/mL) than for men (102 to 105 CFU/mL) and high-risk patients (102 to 104 CFU/mL). Guidelines relied heavily on 48 research articles from 20 author teams published between 1956 and 2019 and recommendations frequently cited 23 research articles by 15 author teams published between 1956 and 2013. Evidence supporting 105 CFU/mL threshold originated in the mid-1950s from 4 research articles, whereas 18 frequently cited peer-reviewed publications focused their research on the clinical relevance of lower thresholds (101 to <105 CFU/mL). This review demonstrates a lack of consensus for urine culture microbial threshold recommendations for the clinical diagnosis of UTI. Guidelines are primarily based upon sparse and dated evidence. Additional research is needed to inform clinically meaningful diagnostic microbial thresholds in the diagnosis of UTI.
Background: Although based on a single system, each laboratory should have their own quality management system, in Ethiopia, quality management systems in medical laboratories were introduced in 2009 with the aim of improving the quality of services. Objective: This review was designed to evaluate the status of quality management practice and challenges among medical laboratories in Ethiopia.Methods: A systematic qualitative review of the literature was made by searching the international electronic bibliographic database of PubMed (NML), web of science (TS), google scholar, African journals online (AJOL) and Cochrane Library.Results: Thirty-six full-text articles, which were published between 2010 and 2022, were included in this review. In this review, 33 of 36 (91.7%) studies showed that status of quality management practice in Ethiopian medical laboratories was limited. As a result, the quality of medical laboratories was inadequate. The main challenges were problems associated with laboratory professionals (35/ 36=97.2%), inadequate support from management bodies (21/36=58.3%), limited on-job training access (8 /36=22.2%) and high workload (5/36=13.8%). Conclusion: The status of quality management practice among medical laboratories in Ethiopia is limited. The main quality compromising factors were problems associated with laboratory professionals, inadequate support from management bodies, high workload, and limited on-job training access. Therefore, all responsible stakeholders should focus on ensuring Quality Management Systems and the system should be applied in all Medical laboratories. Only this will ensure the improvement of quality within medical laboratories across Ethiopia.
Background: Significant advances have been achieved in the clinical implementation of digital pathology (DP) whole slide imaging (WSI). However, the workflow of the reporting process and the full integration of this technology into the lab and hospital information system have not been sufficiently addressed. There is not sufficient vendor and industry consideration for this in the development and implementation process. Methods: Exploring the requirements of direct integration of WSI with the lab and hospital information systems, demonstrating the workflow, challenges and best practices. Mapping and refining the process of movement of the digital slides. The anatomical pathology team, in collaboration with information technology and the vendor, establish the required scripts in order to enable direct integration, therefore allowing the laboratory a highly automated system of case, slide, and report movement. Results: Direct integration was achieved fulfilling the required goals specified by the workflow mapping. An automated case movement process was established in order to enable the pathologist a work management process from the digital platform. The integration errors and challenges were audited and reported. Conclusion: WSI digital pathology integration is achievable; however, it requires significant resource allocation adding to the technology acquirement.
To satisfy the increasing unique characteristics of high precision and heavy-load performance in industrial equipment, a novel self-evolution hourglass worm drive is proposed in this paper. It is consisted of an involute helical beveloid (IHB) gear and an oblique planar enveloping (OPE) hourglass worm, and this worm drive gradually evolves from a local conjugate hourglass worm drive with point contact in the initial meshing state, and a middle meshing state (MES) hourglass worm drive with short-line contact with continuous operation and wear, as well as the finally evolves into a toroidal involute (TI) hourglass worm drive with line contact. According to the differential geometry theory and the spatial meshing principle, the mathematical models of this novel self-evolution hourglass worm drive are established in each evolution stage, the theory of backlash-adjustable is confirmed with introducing a pair of transition tooth surfaces, and the meshing contact area evolution mechanism was defined and elaborated. In addition, the meshing performance evolution of the contact area and the bearing capacity are simulated by numerical analysis including tooth contact analysis and finite element analysis. The analysis results show that with the continuous evolution, the contact area keeps increasing, and the bearing capacity also keeps improving. This study will provide a theoretical basis for the industrial application of this novel hourglass worm drive.
Reliability of machine tools has attracted much attention both in academia and industry. The loading device is very important for the reliability study of CNC machine tools as it can apply multi-axis dynamic forces to the spindle to replace cutting tests. A loading device based on the redundantly actuated parallel manipulator (R5LD) with strong loading capability is proposed in this paper. Firstly, to evaluate the loading capability, this paper proposes new transmission indices for redundantly actuated parallel manipulators (PMs). Besides, the prescribed flexible orientation workspace and regular workspace are defined for the loading device. Then, the corresponding performance atlases are represented graphically in the design space. The structure parameters of the R5LD are achieved in the optimum region of performance atlases. Finally, the R5LD with the optimum parameters is compared with the loading device based on the corresponding non-redundant PM. The R5LD has a larger regular workspace and better transmission performance. The additional UPS chain of the R5LD makes the configuration more symmetrical, balances forces distribution among chains, and strengthens the loading capability of the loading device.
The elderly and those with underlying chronic diseases (i.e., comorbidities) such as pulmonary, cardiovascular, metabolic, and renal diseases, increase their susceptibility to sepsis, including COVID-19. The SARS-CoV-2 virus damages pulmonary cells, causing acute respiratory distress syndrome (ARDS) and hypoxia. It further damages endothelial cells, altering clotting mechanisums causing intravascular hemolysis, microvascular thrombosis, and micro-embolization, contributing to the risk of death. Approximately 75% of the immune system functions of humans depend on vitamin D and the availability of sufficient amounts of vitamin D metabolites [vitamin D and 25(OH)D] concentrations to enter immune cells from the bloodstream. Such concentrations are achievable through sun exposure, targeted food fortification programs, and adequate daily or weekly vitamin D supplements. That would allow for generating 1,25(OH)2D (non-hormonal form of calcitriol) intracellularly in peripheral target cells like immune cells. This enables immune cells' physiological functions, including intracrine/autocrine and paracrine signaling processes. This initiates and maintains robust immune functions, such as forming antibodies and antimicrobial peptides, suppressing inflammation, and increasing the expression of anti-inflammatory and antioxidant genes, thus, strengthening immune functions. The opposite occurs in hypovitaminosis D, increasing vulnerability to infections and dying from it. Therefore, governments should make the population sufficient with immunoceuticals-micronutrients, especially vitamin D, and other micronutrients: the most cost-effective intervention to keep the population healthy. The cost of such interventions are minuscule compared to the expenses related to increased hospitalizations and premature deaths. Supposed such a program was implemented in mid-2020 as the author proposed, we estimated that 50% of hospitalizations (and the associated healthcare costs) and a third of deaths from COVID could have been prevented. Described herein are cost-effective strategies using vitamin D to achieve and sustain serum D3 and 25(OH)D concentrations crucial for maintaining a robust immune system, improving general health, minimizing disease severities and deaths, and reducing healthcare costs.
Primary intraosseous meningioma is a rare tumor arising commonly from the calvarial bone. Here, we report a case of primary intraosseous meningioma which presented as a Bifrontal skull mass in a 30-year-old woman who presented with a progressive forehead enlargement and headache of 3 years duration. Brain CT shows hyperostosis of the frontal bone and microscopy shows intertrabecular syncytial proliferation of oval to spindle cells at the area forming whorl. Even though it is rare, PIM is the most common subtype of extradural meningioma.
: Hydatid cyst of the breast is a very rare disease that predominantly affects endemic regions. Breast hydatid cysts can occur alone or as a component of widespread hydatidosis. Histopathology is the best diagnostic method for hydatid cysts of the breast, but fine needle aspiration cytology can be utilized in preoperative diagnosis. Here we report, a case of a female patient who was diagnosed with Hydatid cyst of the breast Postoperatively in Wolaita Sodo University teaching hospital, southern Ethiopia. Preoperatively the patient was diagnosed with tuberculous mastitis and she took the full course of Anti Tuberculous treatment. After completing the treatment there was no improvement. The cyst was removed surgically and histopathology confirmed the disease to be Hydatid cyst of the breast.
Background: Hereditary spherocytosis is a type of hemolytic anemia characterized by a clinically heterogeneous, genetically defined red blood cell membrane abnormality that results in hemolytic crisis. The inheritance of HS is autosomal dominant in 80% of affected individuals and recessive genes or sporadic type in the remaining 20%. Objective: The main aim of this study was to determine the magnitude of immune hereditary spherocytosis among human immunodeficiency virus-infected adults at the University of Gondar comprehensive specialized hospital in northwest Ethiopia from March to April 2021. Methods: An institution-based cross-sectional study was conducted on 358 human immunodeficiency virus-infected adults selected by systematic random sampling at the University of Gondar comprehensive specialized hospital from March to April 2021. Data for socio-demographic data were collected by structured pretested questionnaire. Five ml of venous blood was drawn from each participant and analyzed by Unicel DHX 800 hematology analyzer, and blood film examination and antihuman globulin test were performed to exclude immune hemolytic anemia. Data was entered into Epidata version 4.6 and analyzed by STATA version 14. Descriptive statistics were computed and drawn in charts and graphs. Results: The prevalence of hereditary spherocytosis was 2 of 358 participants. Both individuals who developed hereditary spherocytosis were females and in the age group of 22 to 35. The overall prevalence of anemia was 91 (25.42%). Of those anemic study population 3 (3.29%), 28 (30.77%), and 60 (65.93%), respectively, had severe, moderate, and mild anemia. Conclusion and Recommendation: Hereditary spherocytosis is a less frequent condition in human immunodeficiency virusinfected adults. In these patients, early detection and treatment are necessary at the familial level by using a test algorithm.
The design and analysis of multi-loop metamorphic mechanisms are challenging in the research of metamorphic mechanisms. Inspired by the parallelogram mechanism, this paper proposes a metamorphic mechanism by adding a link to the parallelogram mechanism and changing the properties of some kinematic joints. The metamorphic mechanism has two loops and is composed of six links connected by six revolute joints and one prismatic joint. The topological structure of the metamorphic mechanism is represented by a directed graph, and the multiple bifurcation of the metamorphic mechanism is analyzed by using screw theory and high-order kinematics. The metamorphic mechanism has six bifurcation points and four different motion branches, including one parallelogram branch, one isosceles trapezoid branch and two oscillating block branches. Meanwhile, by combining these metamorphic mechanisms, some novel metamorphic mechanisms with variable sizes and different configurations can be obtained. The metamorphic mechanism proposed in this paper provides a fresh perspective on how to design new metamorphic mechanisms.
This paper proposes a seamless mode shift control strategy for a Simpson planetary gearset based dual motor powertrain (SPGDMP) which has 6 driving modes. The dynamic model of SPGDMP is built, where the rotational inertia of transmission components, the flexibility of shafts, dynamic response of motor torque and brake pressure, and stick-slipping friction phenomenon of brake are considered. A seamless mode shift control strategy is proposed to avoid power interruption and reduce the vehicle jerk. The mode shift is decoupled to the torque transition process and speed transition process, which lowers the control difficulty. The step function is used to produce the smooth transition trajectories of torque and speed, which eliminates the large vehicle jerk induced by the unsmooth driving torque. In the speed transition process, a combination of speed feedback and torque feedforward control strategy is proposed to track the designed motor speed trajectory and the driver's input torque simultaneously. The simulation results demonstrate that the proposed mode shift control strategy can reduce the peak-to-peak value of vehicle jerk to a value below 2 m/s(3).
