bluuebunny/crossref_metadata_2025 huggingface dataset:
A Randomised Comparative Study to Compare the Prophylactic use of Phenylephrine and Norepinephrine in Caesarean Delivery under Spinal Anaesthesia
Authors: Ali CV Soabir , Bajaj Jeetendra Kumar
Published: April 2023

Background:

To compare the efficacy and safety of prophylactic intravenous infusions of phenylephrine (0.1 mg/kg/min) and norepinephrine (NE) (0.05 mg/kg/min) for the management of maternal hypotension under spinal anesthesia for cesarean delivery.

Methods:

A prospective randomized comparative interventional study was conducted on 100 pregnant patients who underwent elective/emergency cesarean section under the sub-arachnoid block. The study patients were randomly allocated into two equal groups comprising of Group P (n = 50): who received phenylephrine 0.1 mg/kg/min infusion prophylactically and Group N (n = 50): who received norepinephrine 0.05 mg/kg/min infusion prophylactically. The data of outcome measures were compared among the two groups by SPSS ver 21.0.

Results:

A significant difference was seen in the incidence of bradycardia between groups P and N (20% vs 4%, P value = 0.028). The blood pressure was significantly higher in Group N (systolic-120.5 vs 104 mm of Hg, P = 0.026; diastolic-66 vs 61 mm of Hg, P = 0.019). Group N patients had no complications whereas Group P patients experienced nausea (8%) and vomiting (4%), P = 0.027. Neonatal outcomes in terms of Appearance, Pulse, Grimace, Activity, and Respiration (APGAR) score and umbilical arterial/venous blood gases were similar among the two groups (P > 0.05).

Conclusion:

In conclusion, the study results show that NE is better in maintaining the hemodynamic parameters (BP and HR) during spinal anesthesia for cesarean delivery with minimal side effects. It can be suggested that NE may be advantageous in pregnancies especially those complicated with pregnancy-induced hypertension.
Maternal Oxygenation and Neonatal Outcome in Pregnant Women with COVID-19: A Case Series of 20 Patients
Authors: Yamaguchi Takumi , Fujii Tomoaki , Hirate Hiroyuki , Ota Yusuke
Published: April 2023

Purpose:

Management of delivery in pregnant women with coronavirus disease 2019 (COVID-19) is mainly based on extrapolated evidence or expert opinion. This study aimed to assess the clinical manifestations and maternal and perinatal outcomes of COVID-19 during pregnancy.

Methods:

We retrospectively reviewed the cases of 20 pregnant women infected with the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Their demographic data and clinical characteristics, including symptoms, laboratory examination, and imaging findings, were evaluated. We also assessed the delivery method and timing and clinical courses of mothers, including oxygenation and treatment for COVID-19, as well as neonatal outcomes.

Results:

The most common symptoms were fever (65%) followed by cough (45%). Seven cases (35%) of preterm birth were observed. Eight patients (40%) required oxygen administration during pregnancy. Among them, two patients (10%) required a high-flow nasal cannula, and one patient (5%) required venovenous extracorporeal membrane oxygenation (VV-ECMO). No maternal death was observed; however, one instance of severe neonatal asphyxia and one intrauterine fetal death were observed.

Conclusion:

Although most pregnant women with COVID-19 were discharged without any major complications, some cases became severe. Therefore, the timing and method of delivery should be considered for each case to control maternal and infant respiratory conditions.
Combined Spinal-Epidural Anesthetic Management of Delivery for Marfan Syndrome: Case Report
Authors: Malinovic Matea , Babiash Kimberly , Newton Felecia
Published: April 2023

Pregnancy in a patient with Marfan syndrome is associated with risks, including cardiovascular complications. The hemodynamic changes of pregnancy during delivery are deleterious to Marfan syndrome patients. This case describes a Marfan syndrome parturient with dilated aortic root >45 mm who underwent neuraxial anesthesia and cesarean delivery. Anesthetic management focused on reducing hypertension and shear forces on the ascending aorta. A combined spinal-epidural with a reduced dose of hyperbaric bupivacaine was utilized for cesarean delivery. Multidisciplinary approaches are vital in the management of Marfan syndrome pregnancy and cardiovascular complications must be considered when planning for delivery and postpartum management. Anesthetic management must consider the hemodynamic changes in pregnancy and severity of Marfan syndrome cardiovascular involvement in the parturient as well as neonatal risks. Guideline development concerning anesthetic management for both the timing of delivery and aortic repair postpartum would be beneficial to Marfan syndrome parturients.
Vascular Clamps in Perimortem Caesarean Delivery in Parturients with Placenta Accreta Spectrum: Case Report and Literature Review
Authors: Dogra Sandipika , Surampadi Kameswari , Madapu DA Manokanth , Pandya Sunil T
Published: April 2023

The increasing incidence of caesarean section (CS) increases the risk for placenta accrete spectrum (PAS) conditions in pregnancy. The aortic vascular clamps can be used in low resource settings to minimise major obstetric haemorrhage in a parturient with PAS. We report one case of major obstetric haemorrhage attributable to PAS and other cases that had the potential to bleed post-return of spontaneous circulation (ROSC). The first case had torrential bleed following classical CS done for percreta leading to severe haemodynamic instability and a near arrest situation despite standard protocolised management. As a last resort to control catastrophic bleeding, the aortic vascular clamp was used to avert an imminent cardiac arrest, which successfully lead to effective resuscitation and later uneventful recovery. The second case was a perimortem caesarean delivery in a diagnosed case of placenta percreta where we contemplated to use this clamp during resuscitative hysterotomy [Perimortem caesarean delivery (PMCD)] as its usage is likely to confer haemodynamic stability post-ROSC bleeding. However, the patient could not be revived. We have found that in addition to anaesthetic and major haemorrhage management skills in tackling a massive obstetric haemorrhage, the availability of trained surgical teams for controlling ongoing haemorrhage is crucial for effective resuscitation. Using aortic and common iliac vascular clamps as a damage control measure also plays a very important role in controlling catastrophic maternal haemorrhage. With the growing incidence of PAS and uncontrolled bleeding in these parturients, the skilled anaesthetic and resuscitative skills of anaesthesiologists are futile if haemorrhage is not controlled. We found that the availability and use of the vascular clamps at the time of PMCD are very useful to control bleeding and help in effective resuscitation. Its use has a short learning curve and the personnel can be trained easily.
Comparison of Two Different Doses of Magnesium Sulfate as an Adjuvant to Intrathecal Bupivacaine in Patients with Pre-Eclampsia Undergoing Elective Cesarean Section: A Prospective Double-Blind Randomized Study
Authors: Tuteja Swapnil , Gupta Apoorva , Choudhary Savita , Panwar Roshni , Zala Rajeshwar , Bhokan Ravina
Published: April 2023

Background:

Intrathecal magnesium sulfate is now emerging as a safe and effective adjuvant for spinal anesthesia (SA). The aim of the present study was to compare the efficacy of two doses of intrathecal magnesium in parturients with pre-eclampsia.

Methods:

This prospective randomized double-blind study was conducted on 105 parturients undergoing elective cesarean section (CS) who were randomized into three groups of 35 each: Group C, M50, and M75. Group M50 and group M75 received 50 mg of 50% (0.1 ml) and 75 mg of 50% (0.15 ml) magnesium sulfate, respectively. All of the groups received 10 mg of 0.5% heavy bupivacaine with normal saline accordingly to make a total volume of 2.2 ml. The sensory and motor block characteristics, visual analogue scale (VAS) score, post-operative analgesic requirements, hemodynamic parameters, and adverse effects were compared.

Results:

The sensory and motor block characteristics were significantly delayed in group M75 compared to group M50 and the control group (P < 0.05). VAS scores were significantly high in the control group up to 6 h as compared to group M50 and group M75 (P < 0.05). The time to first rescue analgesia was significantly extended in group M75 (222.86 ± 12.502 min) as compared to group M50 (221.14 ± 13.671 min) and the control group (127.43 ± 11.464 min) (
P
< 0.05)

Conclusion:

Intrathecal magnesium sulfate at doses of 50 mg and 75 mg in pre-eclamptic parturients undergoing elective CS results in prolonged duration of analgesia, decreased VAS scores and also delays the first rescue analgesic requirement with a favorable adverse effect profile in terms of decreased incidence of nausea and shivering.
Apparent Acquired Resistance to Local Anesthetics in a Pregnant Patient: Coincidence or a Novel Entity?—A Case Report
Authors: Jaya Lalwani , Sashank Ayalasomayajula , Sruthi Katari
Published: April 2023

We present a case of a 28-year-old pregnant patient in labor with two prior cesarean sections with a history of both successful and failed spinal anesthesia in her first and second pregnancies, respectively. This time, attempts at spinal anesthesia failed twice despite ruling out the common causes such as technical or drug error. Surgery was ultimately performed under general anesthesia uneventfully. While technical factors may contribute substantially to failure of spinal anesthesia, the sequence of events in this case, viz. one successful subarachnoid block followed by two unsuccessful ones three and seven years apart, supported by investigative evidence, indicates a possible acquired resistance to local anesthetics.
Pregnancy-Induced Pituitary Apoplexy: Two Lives at Stake
Authors: Faisal Izhar , Kaushik Teshi , Ganjoo Pragati , Jagetia Anita
Published: April 2023

Pituitary apoplexy in a pregnant woman is a devastating condition that develops secondary to a massive increase in the size of the pituitary gland and hyperplasia of lactotroph cells caused by high estrogen levels of pregnancy. The resultant sudden hemorrhage or infarction into the pituitary gland or a tumor leads to gland destruction with serious consequences like acute adrenal insufficiency, circulatory shock, neurological deterioration, and visual loss. Prompt handling of complications is necessary to prevent maternal and fetal mortality. Resuscitation is aimed at the early correction of hemodynamic instability, fluid-electrolyte abnormalities, hormone deficiencies, and intracranial hypertension. Urgent decompressive pituitary surgery may be required if the patient has rapidly declining vision and neurological status. Management of such patients is challenging and requires multi-disciplinary collaboration. We describe here the emergency handling of pituitary apoplexy in a pregnant woman.
Antichlamydia Antibodies and Sperm Quality among Male Partners of Infertile Couples in Nigeria
Authors: Olibe AO , Udealor PC , Ugwu EO , Iyoke CA , Ugwu AO , Eleje GU , Umeh UA , Iloghalu EI , Agu PU , Obioha KC , Onwuka CI
Published: April 2023

ABSTRACT

Background:

The impact of Chlamydia trachomatis on semen quality has been studied with varied results.

Aim:

To determine the prevalence of antichlamydial antibodies and their relationship with sperm quality among male partners of infertile couples in Enugu, South-East Nigeria.

Materials and Methods:

It was a cross-sectional study of infertile male partners of couples attending infertility clinics at the University of Nigeria Teaching Hospital (UNTH) Ituku-Ozalla, Enugu, Nigeria. Their sera were assayed for antichlamydial antibodies, and semen analysis and culture were done for each participant.

Results:

Two hundred and eighty-two (282) male partners of infertile couples were studied. Infertility was commoner among participants aged 40 years or more (45.1%) and was mainly of the “primary type” (62.1%). Antichlamydia antibody was detected in 156 (55.3%) participants and was significantly associated with sperm quality (P = 002; OR = 2.294; 95% CI = 1.36–3.88). Overall, 81 (28.7%) had abnormal sperm quality. The sperm count, progressive motility, and vitality were significantly lower in participants with abnormal sperm quality than those with normal sperm quality (P < 0.001) while morphology, volume, and liquefaction time did not differ significantly (P > 0.05). Staphylococcus aureus was the predominant organism isolated from culture (122/282, 43.3%) while Streptococcus species were the least (4/262, 1.4%). There was significantly more Staphylococcus aureus isolated from the semen of participants that were seropositive to antichlamydial antibodies than those that were seronegative (80/156, 51.3% vs. 42/126, 33.3%; OR = 2.105; 95% CI = 1.30–3.42; P = 0.003).

Conclusion:

The prevalence of antichlamydial antibodies among male partners of infertile couples in Enugu, Nigeria is high and there is a significant association with sperm quality, sperm count, and bacterial isolates in seminal culture. Male partners of infertile couples in Enugu should be screened for antichlamydial antibodies and appropriate treatment offered wherever indicated. There is a need for increased public awareness and advocacy campaigns on the impact of Chlamydia infection on male factor infertility. This primary preventive measure may help in reducing the burden of Chlamydia infection and male factor infertility.
The Effects of Nursing Interventions on the Level of Anxiety and Care Burden of the Caregivers of Bedridden Patients
Authors: Bayrak B , Özkan ÇG , Demirbag BC
Published: April 2023

ABSTRACT

Background:

Taking care of bedridden patients at home is a very difficult task for caregivers. In this care process, caregivers can be supported with the interventions given by the nurses at home.

Aim:

This study mainly aimed to compare the anxiety and care burden levels of caregivers of bedridden patients at home after nursing interventions which a personal care handbook, regular home visits, and telephone counseling.

Subject and Methods:

To proceed with this study, 51 caregivers have included in this study between January 1 and July 21, 2018. The Barthel Index for Activities of Daily Living (BIADL) was used to measure levels of independence in patient’s activities, State and Trait Anxiety Scale (SAI and TAI) was used to measure the anxiety levels, and Burden Interview (BI) care burden problems of caregivers who participated in the study. Also, Sociodemographic Characteristics Form was used for demographic data of patients and caregivers.

Results:

The analysis of the responses showed the proportions of the caregivers who had lower SAI- TAI and BI scores after taking nursing intervention at home. The state anxiety level of caregivers (pre-test: Mean; 54.06+-7.97; post-test: Mean; 38.43+-6.41) and the trait anxiety level of the caregivers (pre-test: Mean; 51.45+-5.94; post-test: Mean; 41.59+-7.05) and the burden level of caregivers (pre-test: Mean; 75.75+-11.41; post-test: Mean; 57.69+-13.39) was determined. The differences between the pre and post-test mean scores of SAI, TAI, and BI were statistically significant (P < 0.05).

Conclusions:

Our study highlights that the burden and anxiety levels of the caregivers had lower post-test levels than the pre-test levels.
The Effects of Radiotherapy on Arterial Diameters in Patients with High-Grade Glial Tumors Who Have Undergone Adjuvant Radiotherapy
Authors: Karaca F , Menteş S , Boğa Z , Akkaya H , Keskin S , Gülek B
Published: April 2023

ABSTRACT

Background and Aims:

Our purpose was to evaluate the M2 branch of the middle cerebral artery (MCA) in high-grade glial tumor patients who undergo adjuvant radiotherapy (RT). For this purpose, the diameter of the M2 branch was measured and evaluated by means of contrast-enhanced magnetic resonance imaging (CE-MRI) before and after RT. Post-radiotherapeutical measurements were made 1, 3, 5, and 7 months after the procedure; and vascular diameter alterations were evaluated.

Materials and Methods:

CE-MRI examinations were performed on the 32 patients enrolled in the study, who had undergone radiotherapy of the temporoparietal region. MRI examinations were performed prior to RT (RT0) and 1 (RT1), 3 (RT2), 5 (RT3), and 7 (RT4) months after RT. The M2 branch of the MCA was evaluated on MRI images, and the vessel diameter was measured in millimeters (mm), and then comparisons were made.

Results:

Statistically significant results were obtained during RT0-RT1, RT0-RT2, RT0-RT3, RT0-RT4, RT1-RT2, RT2-RT4, and RT3-RT4, and comparisons of the diameters of the M2 branch of the right MCA were performed (P < 0.05). When the same measurements and comparisons were made for the M2 branch of the left MCA, statistically significant results were found for the RT1-RT2, RT1-RT3, and RT1-RT4 comparisons (P < 0.05).

Conclusion:

Our study showed that the MCA M2 branch diminished in size following RT. This was demonstrated by means of CE-MRI controls performed up to 7 months after the completion of the RT procedures.
Determinants of Blood Pressure Control among Hypertensive Patients Attending a Rural Teaching Hospital in Southern Nigeria
Authors: Oseni TIA , Emonriken A , Ahmed SD , Dic-Ijiewere M
Published: April 2023

ABSTRACT

Background:

Hypertension (HTN) is the commonest cardiovascular risk factor in sub-Saharan Africa. It is a global public health threat, often associated with significant morbidities and mortality with rising prevalence both in rural and semi-urban areas of economically disadvantaged countries.

Aim:

This study aimed to assess the determinants of blood pressure control among patients with hypertension receiving care at the Irrua Specialist Teaching Hospital in Southern Nigeria.

Patients and Methods:

A cross-sectional study of 502 consenting hypertensive adults receiving care at the Irrua Specialist Teaching Hospital, Irrua in Edo State, South-south Nigeria. A pre-tested semi-structured interviewer-administered questionnaire was used to collect data which was analyzed using SPSS version 21 and the level of significance was set at P < 0.05.

Results:

Five hundred and two participants (226 males, 276 females) completed the study with a mean age of 52.98 ± 12.82 years. Optimal blood pressure control was found in 15.5% of the study participants. Blood pressure control was significantly associated with being married (OR 1.549, CI: 1.040-2.309), having a monthly household income of over N50,000 (OR 1.691, CI: 0.999-2.863), engaging in physical activity (OR = 1.537, CI: 0.989-2.388), and not being obese evidenced by a normal Waist Hip Ratio (OR = 2.276, CI: 1.555-3.332).

Conclusion:

Blood pressure control to target goal was low in the study population and achieved only in less than one-fifth of respondents on antihypertensive therapy. Numerous socio-demographic and lifestyle variables were shown to be associated with blood pressure control. Physicians should emphasize medication adherence and lifestyle modification approaches in hypertensive adults.
Evaluation of Immediate Implant Placement with Osteotome Sinus Floor Elevation without Graft Material
Authors: Tamer Y
Published: April 2023

ABSTRACT

Background:

Significant difficulties can be encountered when installing posterior maxillary implants. Osteotome sinus floor elevation (OSFE) enables insertion of implants with insufficient bone height at the posterior maxilla using a special instrument known as the “osteotom.”

Aim:

This study aimed to evaluate the implant survival rates and radiographical bone gain data after OSFE with simultaneous implant placement performed without grafting material. Further, we have discussed whether the osteotom tapping distance to sinus floor affects the amount of new bone gain (NBG).

Materials and Methods:

Forty dental implants were inserted in 36 patients (20 women and 16 men) aged between 24 and 80 years (mean = 55.7 years). Residual bone height and NBG were analyzed using a commercially available software program on panoramic films.

Results:

The mean residual bone height at the intended implant sites was 5.4 mm ± 2.2 mm, ranging from 3.5 mm to 6.9 mm. The mean NBG was 1.5 mm ± 0.87 mm, ranging from 0.1 mm to 4 mm. At 64.4 months of follow-up, one implant had been lost in the osseointegration period. The remaining 39 implants were in function, with a survival rate of 97.5%. No significant difference was seen between the osteotome tapping distance to sinus floor and NBG at the implant apex (P = 0.395).

Conclusion:

OSFE without using bone grafts with simultaneous implant installation is a safe and reliable method with successful long-term results for he rehabilitation of edentulous posterior maxillae.
Evaluation of Steroid Therapy in COVID-19 Patients; in the Right Dose at the Right Time to the Right Patients
Authors: Ayyıldız A , Yıldırım ÖT , Uçan A , Ayyıldız FA
Published: April 2023

ABSTRACT

Background:

Although there is still no universally accepted treatment agent, steroids have been administered chronologically at every dose and at every stage of the COVID-19 pandemic.

Aim:

We aimed to evaluate the clinical efficacy of high-dose steroid therapy and its effect on mortality in COVID-19 patients with severe pneumonia, severe Acute Respiratory Distress Syndrome (ARDS), and septic shock.

Patients and Methods:

Patients with severe pneumonia, septic shock, and ARDS due to COVID-19 who were followed up in the intensive care unit were retrospectively reviewed.

Results:

The study population was divided into two groups; the methylprednisolone pulse group (MP) (n = 55) and the dexamethasone group (Dex) (n = 39). When the values before and after treatment were compared; there was a statistically significant increase in the neutrophil/lymphocyte ratio after treatment in the MP group (p = 0.006). Although it was not statistically significant in the MP group, There was a numerical increase in D-dimer levels (p = 0.28). Thromboembolic complications developed in 2 patients in the MP group. The mortality outcomes of the groups were statistically similar (p = 0.943).

Conclusion:

We recommend steroids use in the condition that it is indicated in the critically ill group with the poor general condition. Since there is no significant difference between high-dose pulse steroid treatment and standard treatment doses, we think that the risk of complications should not be taken into account and high doses should not be used.
Apoptosis in Physiological Root Resorption of Primary Teeth
Authors: Turan Y , Akal N , Yildirim B , Kaymaz F , Baris E
Published: April 2023

ABSTRACT

Background:

During physiological root resorption of deciduous teeth, apoptotic cell death triggered by physiological processes might play a role in physiological root resorption in addition to collagen destruction. Little information has been obtained about the sequence of events and the mechanism responsible for the physiological death of pulp tissue cells.

Aim:

This study evaluated apoptotic cell death in the pulp tissue of deciduous teeth that showed various levels of physiological root resorption. The role of apoptosis in pulp tissue elimination during the physiological resorption of deciduous teeth was also examined.

Materials and Methods:

For orthodontic reasons, 12 healthy permanent teeth and the pulp of 34 healthy deciduous teeth showing signs of early and advanced root resorption were extracted. To detect apoptotic cells in the pulp tissue, the terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) method and transmission electron microscopy (TEM) were used. The apoptotic index (AI) values of the study groups were determined using the TUNEL method. This technique required calculating the Apoptag positive(+) fibroblast cell ratio in accordance with the total number of cells.

Results:

No statistically significant differences were found for the AI values of each study group (p>0.05). Apoptosis was detected in the vascular endothelial cells, the mononuclear inflammatory cells, and the odontoblasts of the connective pulp tissue. In the pulp tissue, evaluated using TEM, various pulp cells were observed at distinct stages of apoptosis.

Conclusion:

The similarity between the AI values for both study groups suggested that in early and advanced stages of resorption, apoptosis may contribute to the regulation of the pulp cell population in a way that does not relate to the physiological process of deciduous teeth root resorption.
Mask-Associated Dry Eye (MADE) in Healthcare Professionals Working at COVID-19 Pandemic Clinics
Authors: Celik E , Polat E , Gunder EK , Barut E , Gonen T
Published: April 2023

ABSTRACT

Background:

Healthcare professionals working at COVID-19 pandemic clinics have to work with masks during long hours. After the widespread use of masks in the community, many mask-related side effects were reported to clinics. The increase in the number of applicants with dry eye symptoms due to mask use in ophthalmology clinics has led to the emergence of the concept of mask-associated dry eye (MADE). We think that it would be valuable to evaluate ocular surface tests with a comparative study using healthcare professionals working in pandemic clinics, which we think is the right study group to examine the effects of long-term mask use.

Aims:

We aimed to evaluate the mask-associated dry eye (MADE) symptoms and findings in healthcare professionals who have to work prolonged time with face masks in coronavirus disease 2019 (COVID-19) pandemic clinics.

Patients and Methods:

In this prospective, observational comparative clinical study, healthcare professionals who use the mask for a long time and work in COVID-19 pandemic clinics were compared with an age and sex-matched control group consisting of short-term masks users, from April 2021 to November 2021. All participants underwent the Ocular Surface Disease Index (OSDI) questionnaire, tear film break-up time (T-BUT), Oxford staining score, Schirmer’s test I, and meibography with infrared transillumination.

Results:

The long-term mask user group consisted of 64 people, while the short-term mask user group consisted of 66 people (260 eyes, total). The OSDI score and Schirmer I measurement were not statistically different between the two groups. T-BUT was statistically significantly shorter in the long-term group (P: 0.008); lid parallel-conjunctival fold, Oxford staining score, and upper and lower lid meibography score were found to be significantly higher in the long-term group (P < 0.001, P: 0.004, P: 0.049, P: 0.044, respectively).

Conclusion:

Healthcare professionals with longer mask-wearing times are at greater risk of ocular surface damage. It may be considered to prevent this damage by blocking airflow to the ocular surface, such as by wearing a face mask properly or fitting it over the nose with surgical tape. Those who have to work with a mask for a long time during the COVID-19 pandemic should keep in mind the ophthalmology follow-up for eye comfort and ocular surface health.
Normal Central Foveal Thickness in a Thousand Eyes of Healthy Patients in Sub Saharan Africa Using Fourier Domain Optical Coherence Tomography
Authors: Oderinlo O , Bogunjoko T , Hassan AO , Idris O , Dalley A , Oshunkoya L , Odubela T
Published: April 2023

ABSTRACT

Background:

Optical coherence tomography provides high resolution in vivo images of the retina which are essential for diagnosis and follow up of patients with retina disorders like macula edema and exudative age-related macular degeneration. Establishing the normal range of central fovea values in our population provides vital baseline data for comparison.

Aim:

To report the range of normal central fovea thickness measurements in eyes of healthy hospital patients in sub-Saharan Africa using a commercially available Fourier domain optical coherence tomography (OCT) scan.

Patients and Methods:

A retrospective non-comparative review of case files of a thousand consecutive healthy patients who had retina OCT scans between January 2015 and December 2019 was done.

Results:

Data from 1000 consecutive eyes of 500 healthy patients were used for the study. There were 181 females and 319 males. The mean central foveal thickness was 239.48 microns (μm), with a minimum thickness of 200.0 μm and maximum thickness of 297.0 μm. Males had significantly (P < 0.001) thicker mean CFT (mean CFT = 241.77 μm) compared with females (mean CFT = 235.43 μm). The mean CFT increased with age of participants by 0.139 μm (P < 0.001) for every year of life below 70.

Conclusion:

The mean central foveal thickness (CFT) in eyes of healthy patients in our study was 239.48 μm with a range from 200 μm to 297.0 μm. Males had thicker mean CFT compared with females and there was a significant increase in mean CFT by 0.139 μm (P < 0.001) for every year of life below 70.
Retained Lumbar Intradural Bullet Fragment with Neurological Recovery after Delayed Removal of Bullet: Case Report and Literature Review
Authors: Ibebuike KE
Published: April 2023

ABSTRACT

Civilian gunshot wound (GSW) to the spine is expected to increase in our environment due to the recent surge in violence and firearm attacks in the society either by herdsmen, bandits, unknown gunmen, or from exchange of gun fire with security personnel in response to insecurity issues. The management of GSW in the spine remains controversial, with no clear recommendations for surgical intervention by spine surgeons. In light of this, we report a case of civilian GSW to the lumbar spine in a 47-year-old female with resultant immediate paraplegia. Neuroradiological studies revealed a large bullet lodged in the left L2/3 spinal canal. There was a 4-week wait for consent for surgery to be obtained, with no improvement in motor function during the period. She underwent laminectomy and duratomy with removal of the bullet. Motor function returned 3 weeks after the surgery, and she was discharged home 8 weeks after the surgery, actively mobilizing on a Zimmer frame. The case report demonstrates the beneficial role of surgical intervention in properly selected patients, with resultant satisfactory functional neurological recovery.
Relapse of Melanoma Presenting as Jejunal Intussusception
Authors: Özdede M , Güven AT , Yerebakan MB
Published: April 2023

ABSTRACT

Melanoma is a relatively rare tumour with tendency to metastasize to the gastrointestinal tract. Metastasis to the intestine constitutes a majority of the gastrointestinal tract melanoma metastases and confers a poor prognosis. While post-mortem studies detect that more than half of the melanoma patients have gastrointestinal tract metastasis, only minority are diagnosed, and even rarer present with intussusception. Intussusception, mainly a paediatric entity, is also seen among adult patients with underlying inflammatory bowel disease or tumour. In this report, we describe a patient with a melanoma in remission who presented with intestinal obstruction after months of vague abdominal complaints. Laparotomy revealed jejunal intussusception and histopathological staining confirmed the melanoma diagnosis. No other distant metastases other than the jejunum were revealed after extensive investigation.
The Lynchpin—A Novel Geometry for Modular, Tangential,
Omnidirectional Flight
Authors: Howard Terrence Dashon , Molter Christian , Seely Chris Dale , Yee Jeff
Published: April 2023

A novel geometry for a six degrees of freedom (6DOF) unmanned aerial vehicle
(UAV) rotary wing aircraft is introduced and a flight mechanical analysis is
conducted for an aircraft built in accordance to the thrust vectors of the
proposed geometry. Furthermore, the necessary mathematical operations and
control schemes are derived to fly an aircraft with the proposed geometry. A
system identification of the used propulsion system with the necessary thrust
reversal in the form of bidirectional motors and propellers was conducted at a
whirl tower. The design of the first prototype aircraft is presented as well as
the first flight test results. It could be demonstrated that an aircraft with
the thrust vectors oriented according to the proposed geometry works
sufficiently and offers unique maneuvering capabilities that cannot be reached
with a conventional design. The biggest limiting factor could be identified to
be the latency resulting from the time needed to reverse the direction of
rotation of the bidirectional propellers. Special operational handling
considerations for a manually flown 6DOF vehicle are summarized, and different
approaches to control such a vehicle are described. Different mission scenarios
and applications for a single aircraft in this design are concluded. Due to the
symmetrical properties of the proposed geometry, several aircraft can also be
connected at different orientations in flight. Consequently, the possibilities
of docking in midair are illustrated, and possible mission scenarios for a group
of aircraft, working together collaboratively, are presented. Especially when
operated autonomously in a group of aircraft, new possibilities evolve from the
capability of the proposed geometry to bond in different orientations.
Torque Distribution Control Strategy of Electric Wheel Loader with Multiple Drive Motors Based on Optimal Motor Efficiency
Authors: Wang Yang Yang , Hu Yulun , Ming Qiaohong
Published: April 2023

Wheel loaders are widely used in construction projects. In order to reduce pollution and energy consumption, major wheel loader manufacturers are developing electric powertrain technology. Our main research goal is to reduce the energy consumption of a pure electric loader. This study is intended to build a vehicle simulation model of a multiple drive motor electric loader. According to the common working conditions and empirical formulas of the loader, the simulation data of the electric loader are calculated. The torque distribution control strategy based on the optimal efficiency of the motor is designed for the multiple drive motor electric loader and is compared with the equal proportion distribution control and the axle load ratio distribution control through simulation analysis. The simulation results show that the proposed torque distribution control strategy based on motor optimal efficiency can reduce energy consumption by 7–12%.
Pre-emptive Braking Control for Stability Improvement of Autonomous
Vehicles on a Curved Road Based on Vehicle-to-Everything
Technology
Authors: Huang Chaoqun , Lai Fei
Published: April 2023

Vehicle-to-everything (V2X) technology has played an important role in improving
the active safety of autonomous vehicles. In order to improve the stability of
the autonomous vehicle on the curved road, this article presents a pre-emptive
braking control method based on V2X technology. Instead of using the active
safety system to try to stabilize the vehicle in case of danger, the pre-emptive
braking action is proposed to reduce the vehicle speed in advance to a level
that allows safe navigation of the turn to avoid danger. It is assumed that the
friction and curvature of the curved road ahead can be obtained through V2X
technology. Combined with a linear two degrees of freedom (2-DOF) bicycle model,
an optimal control method is adopted to calculate the front and rear wheel
steering angles to track the centerline of the curve lane. A more complex
vehicle dynamics model established earlier is selected for simulation analysis
to verify the proposed control method. The results show that the proposed
control method can improve greatly the stability of the autonomous vehicle on
the curved road.
Implementation of the Correction Algorithm in an Environment with
Dynamic Actors
Authors: Omwansa Mark , Meyer Richard
Published: April 2023

Safe navigation of an autonomous vehicle (AV) requires a fast and correct
perception of its driving environment. Meaning, the AV needs to persistently
detect and track moving objects around it with high accuracy for safe
navigation. These tasks of detection and tracking are performed by the AV
perception system that utilizes data from sensors such as LIDARs, radars, and
cameras. The majority of AVs are typically fitted with multiple sensors to
create redundancy and avoid dependence on a single sensor. This strategy has
been shown to yield accurate perception results when the sensors work well and
are calibrated correctly. However, over time, the cumulative use of the AV or
poor placement of sensors may lead to faults that need correcting. This article
proposes an online algorithm that corrects the faulty perception of an AV by
determining a set of transformations that would align a cluster of measurements,
from a moving vehicle in the scene to a corresponding detection in an image
taken by the synchronized, forward-facing camera of the AV. The correction
algorithm is first tested, assuming the availability of ground truth information
to correct the LIDAR, and then tested with camera images which are used to
determine ground truth. The comparison metric between expected and optimal
parameters is the mean absolute error (MAE). The translation, scale, and
orientation errors between the expected and optimal parameters when using ground
truth data in the correction algorithm are 9.41 × 10–4 m, 3.84 ×
10–7, and 3.82 × 10–2 degrees, respectively; and the
errors for camera images are 0.414 m, 0.017, and 0.007 degrees,
respectively.
Letter from the Special Issue Editors
Authors: Hu Xiaosong , Xu Bin
Published: April 2023

Letter from the Special Issue Editors
Experimental Investigation and Analysis of Homogeneous Charge Compression Ignition in a Two-Stroke Free-Piston Engine
Authors: Schneider Stephan , Friedrich Horst E.
Published: April 2023

The present paper deals with the experimental investigation of homogeneous charge compression ignition in a free-oscillating two-stroke free-piston engine. The Free Piston Linear Generator (FPLG), which is being developed at the German Aerospace Center (DLR), is an innovative internal combustion engine for the generation of electrical power. This concept can for example be used in hybrid electric vehicles, as an auxiliary power unit or in combined heat and power units. The FPLG consists of three main components. In the two-stroke combustion unit, heat is released by burning a fuel-air mixture and a piston is accelerated. This energy is then converted into electric energy in the second component, the linear generator. This subsystem consists of electromagnetic coils as a stator and permanent magnets as a mover. The mover is rigidly coupled to the combustion piston. The third component, the gas spring, serves as an intermediate energy storage and reverses the piston motion by decelerating it. With this arrangement, the piston oscillates freely between the compression chamber of the combustion unit and the gas spring with no mechanical coupling like a crank shaft. Due to the free piston movement, the top and bottom dead centers and consequently for example the compression ratio are no longer fixed. This freedom and the use of a fully variable valve train provide the opportunity for a fundamental optimization of the internal combustion process.

The homogeneous charge compression ignition (HCCI) is one advantageous combustion process which leads to low raw emissions and high efficiencies. As a basis to utilize a HCCI process, the paper firstly presents a strategy for the transition between the spark ignition mode and HCCI-mode in the FPLG using the high variability of the engine concept. The auto ignition of the lean fuel-air mixture is enabled by the adaption of the compression ratio and an internal exhaust gas recirculation. The latter is accomplished by an early intake valve opening and intermediate storage of combustion gases in the intake manifold. Additionally, the challenges that come with a freely oscillating piston will be discussed here. In the analysis of the experimental results, the pressure curve and free piston movement will be discussed in detail. Due to the free piston movement stochastic variations in the ignition can be equalized by the system without external control. This effect and the measured efficiencies show the promising potential for the HCCI process in free-piston engines.
Research on Method for Classifying Injury Severity Using Motorcycle Accident Data for ISO 26262
Authors: Arai Yuji , Hasegawa Makoto , Harigae Takeshi
Published: April 2023

ISO 26262 was established in 2011 as a functional safety standard for passenger cars. In this standard, ASILs (Automotive Safety Integrity Levels) representing safety levels for passenger cars are determined by evaluating the hazardous events associated with each item constituting an electrical and/or electronic safety-related system according to three evaluation criteria including injury severity. On the other hand, motorcycles will be included in the scope of application of ISO 26262 in the next revision. It is expected that a severity evaluation for motorcycles will be needed because motorcycles are clearly different from passenger cars in vehicle mass and structure. Therefore, this study focused on severity class evaluation for motorcycles. A method of classifying injury severity according to vehicle speed was developed on the basis of accident data. In addition, a severity table for motorcycles classifying injury severity according to vehicle speed for each accident type was produced using accident data involved with motorcycles in Japan.
Detailed Diesel Combustion and Soot Formation Analysis with Improved Wall Model Using Large Eddy Simulation
Authors: Zhou Beini , Horikoshi Masahiro , Kikusato Akira , Kusaka Jin , Daisho Yasuhiro , Sato Kiyotaka , Fujimoto Hidefumi
Published: April 2023

A mixed time-scale subgrid large eddy simulation was used to simulate mixture formation, combustion and soot formation under the influence of turbulence during diesel engine combustion. To account for the effects of engine wall heat transfer on combustion, the KIVA code's standard wall model was replaced to accommodate more realistic boundary conditions. This were carried out by implementing the non-isothermal wall model of Angelberger et al. with modifications and incorporating the log law from Pope's method to account for the wall surface roughness. Soot and NOx emissions predicted with the new model are compared to experimental data acquired under various EGR conditions.
Acceleration Performance Analysis for Rubber V-Belt CVT with Belt Tension Clutching
Authors: Okimura Yusuke , Sakamoto Moriyuki , Itoo Seiji , Yamasaki Akiyuki
Published: April 2023

The power train system for Utility Vehicles (UVs) or All-Terrain Vehicles (ATVs) mainly consists of a rubber V-belt CVT. The adjustment of the CVT specification requires many steps to realize the shifting operations of the CVT so as to satisfy the acceleration feeling of the driver.

In this paper, we report on the simulation technology that predicts the transient behavior during an acceleration of the vehicle equipped with a belt tension clutching CVT, which has both functions of the shift operation and the clutch action. By using the developed simulation technique, it has become possible to adjust the CVT specifications efficiently.
Development of Black Surface Treatment Applicable to Bolts for Motorcycles
Authors: Yoshida Hiroyuki , Hirayama Hiroshi , Mochizuki Shinsuke , Inoue Manabu , Kato Yasuhiro , Inomata Toshiki
Published: April 2023

A black surface treatment without using hexavalent chromium and applicable to bolts of motorcycles has been developed. The surface treatment also satisfies the requirements of bolts for motorcycles such as fastening performance, corrosion resistance, weather resistance and appearance of outer finish.

There is a method of coating a black chemical conversion film using trivalent chromium on the zinc-plated surface as one of the surface treatments that do not use the hexavalent chromium. Such a black film, however, is thinner than the film using hexavalent chromium, and unable to ensure satisfactory black appearance. Meanwhile, although the dip-coating using a black paint can provide a sufficient black color, it is necessary to apply coating two times to eliminate an irregular color. As a result, thick paint films are formed on the roots of thread, making it difficult to fit into the internal thread. To simultaneously solve the above-mentioned two issues, two measures were executed. One was to apply the black film using trivalent chromium as an undercoat of dip-coating. The second was to develop paints that the amount of pigments in paints was adjusted on the assumption of the color of the undercoat. Thus a proper fit of thread was ensured when fastening in addition to a satisfactory black appearance even with the dip-coating only once. Also, the friction coefficient was controlled at an appropriate level by the selection of friction modifier. Moreover, the adhesion was improved by the enhancement of anchor effect of coating with the elimination of finishing process of the black chemical conversion film, and the requested corrosion resistance was achieved.
Influence of Ca-, Mg- and Na-Based Engine Oil Additives on Abnormal Combustion in a Spark-Ignition Engine
Authors: Miura Kenta , Shimizu Kento , Hayakawa Norikuni , Miyasaka Tomomi , Iijima Akira , Shoji Hideo , Utaka Toshimasa , Tamura Kazushi , Kamano Hideki
Published: April 2023

One issue of downsized and supercharged engines is low-speed pre-ignition (LSPI) that occurs in the low-speed and high-load operating region. One proposed cause of LSPI is the influence of the engine oil and its additives. However, the effect of engine oil additives on pre-ignition and the mechanism involved are still not fully understood. This study investigated the influence of engine oil additives on abnormal combustion in a spark-ignition engine. A four-stroke air-cooled single-cylinder engine with a side valve arrangement was used in conducting combustion experiments. The research methods used were in-cylinder pressure analysis, in-cylinder visualization and absorption spectroscopic analysis. Engine oil additives were mixed individually at a fixed concentration into a primary reference fuel with an octane number of 50 and their effect on knocking was investigated.
Application of Adaptive Idle Speed Control on V2 Engine
Authors: Yin Jie , Syu Yong Fu , Chen Bo-Chiuan , Wu Yuh-Yih , Liang Yao Chung , Tsai Hsien-Chi
Published: April 2023

This paper develops an adaptive idle speed control strategy for a V2, 1000 cc four-stroke, water-cooled, port injection SI engine. In order to verify the proposed strategy, the non-dimensional engine model including charging and torque dynamics is established in Matlab/Simulink software based on previously experimental verification. The integration of dynamics above will be a multi-input-single-output (MISO) system, which inputs are throttle angle and spark advance angle, and the output is engine speed. The proposed adaptive controller is developed on the model-based structure. The system parameters are updated by recursive least square (RLS) method so the system is able to represent the actual operation. The updated system parameters adjust control gain by derivation of closed-loop gain and pole placement. This research also applies RLS method in torque load identification, and uses feedforward control module to calculate the desired throttle opening for the corresponding engine torque. The feedforward throttle control makes controller less angle of spark advance, therefore, the tracking time could be reduced. In order to verify the proposed adaptive idle speed controller performance, the conventional proportional integral derivative (PID) idle speed controller is established. The results show the proposed feedforward adaptive controller can obviously improve about 40% of tracking time with ramps load. In addition, when the water pump load is added, the proposed strategy can also improve about 20%. Finally, the results of the proposed strategy are also improved comparing to the conventional PID control as deposits happen.