International journal of clinical and experimental medicine, 2013
In the pediatric hematology-oncology population, lumbar punctures (LP's) are commonly perform... more In the pediatric hematology-oncology population, lumbar punctures (LP's) are commonly performed to administer intrathecal chemotherapy and obtain CSF samples. Difficult LP's can arise due to obesity, fibrous tissue formation due to repeated LP procedures, or spinal abnormalities. For difficult LP's that require imaging-guidance, fluoroscopy is generally?? Fluoroscopy, however, subjects the patient and healthcare providers to radiation while also potentially increasing procedure cost and time. We retrospectively studied the utility of ultrasound-guidance to facilitate LP in 4 pediatric hematology-oncology patients. All 4 patients had a history of difficult LP and 3 of 4 had previously required use of fluoroscopy. With the use of ultrasound, the LP was successfully performed in all 4 patients with one attempt (number of attempts not recorded in one patient). Procedure time was less than 20 minutes in all 4 patients. Our preliminary data suggests that ultrasound may be an e...
Summary The continuum damage mechanics is used to describe the constitutive behavior of UD lamina... more Summary The continuum damage mechanics is used to describe the constitutive behavior of UD laminate with damage. The progressive fiber fracture, as it is affected by interface strength, debonding growth and matrix cracking, is considered as a main damage mechanism causing the stiffness reduction. The internal state variable that accounts for fiber fracture is formulated within the used theory. The
The effects of extreme environmental conditions on damage evolution and lifetime of long fiber po... more The effects of extreme environmental conditions on damage evolution and lifetime of long fiber polymer based composites are studied experimentally and theoretically. The exposure to salt water is the extreme environmental conditions that are considered in this study. The ...
Permian and Paleocene-Eocene limestone outcrops are exposed in Western Salt Range that contains c... more Permian and Paleocene-Eocene limestone outcrops are exposed in Western Salt Range that contains colossal quantity of mineable aggregates. Engineering properties of Wargal and Lockhart formations, Sakesar Limestone and Kalabagh Conglomerate indicated that these crushed rock aggregates could safely be used in civil work projects. Values calculated for Permian and Paleocene-Eocene limestone resources for specific gravity, water absorption, soundness, Los Angeles abrasion test, Proctor test, optimum moisture content, California bearing ratio and bitumen adhesion were much below the prescribed standards. These aggregates exhibited excellent petrographic properties and were innocuous in plain cement concrete. Moreover, they found to be hydrophobic in nature and therefore, their bond with bitumen would be durable. Development of quarries, following the environmental codes, around Dhak Pass area would provide low cost good quality crushed rock aggregate resources for Mianwali, Jhang, Bhakka...
The Kawagarh Formation is dominantly composed of limestone with subordinate dolomite and marl. It... more The Kawagarh Formation is dominantly composed of limestone with subordinate dolomite and marl. It was deposited in warm tropical homoclinal ramp settings at 23˚S latitude when the Indian Peninsula collided with the Kohistan Island Arc at ca. 65 Ma. The present study involves detailed sampling of eight stratigraphic sections, petrographic analysis (n=880), XRD (n=15), major (Ca and Mg) and minor (Sr, Na, Mn and Fe) trace element geochemistry (n=110), and stable isotopic (δ18O and δ13C) signatures (n=32). The petrographic studies demonstrate that Kawagarh Formation has been subjected to complex diagenetic history including compaction, minor dripstone, meniscus cementation and dolomitization. Close packing of grains, point contacts, dissolution seams and stylolites indicate effects of both mechanical and chemical compaction. Mostly dissolution seams are parallel to bedding and may have dolomite or clays. Stable isotope analyses indicate depleted δ18O signatures (-3.70 to -7.81‰ PDB) of...
Present studies document the temporal variations in petrographic, geochemical and isotopic signat... more Present studies document the temporal variations in petrographic, geochemical and isotopic signatures observed a thick siliciclastic and carbonate succession in Kawagarh Formation (Late Turonian to Lower Maastrichtian), Hazara Basin, NW Lesser Himalayas, Pakistan. In Lower Maastrichtian, the Hazara Basin exposed when Indian Plate established its contact in the north with Kohistan Island Arc. The Kawagarh Formaion is composed of limestone with subordinate dolomite/dolostone and marls. The limestone is fine grained and breaks with conchoidal fractures. The dolomite in all the studied sections of Kawagarh Formation is fine crystalline to coarse crystalline. The crystal texture of the dolomite in replacement mosaics varies from hypidiotopic to idiotopic. Minor amounts of dolomite crystals are xenotopic. At places, turbid cores, rhombic to irregular in shape were observed. Major and trace element studies (Ca, Mg, Sr, Na, Mn and Fe), stable isotopes (δ18O and δ13C) and X-ray diffraction a...
Diaphragmatic injuries are quite uncommon and often result from either blunt or penetrating traum... more Diaphragmatic injuries are quite uncommon and often result from either blunt or penetrating trauma. Diaphragmatic ruptures are usually associated with abdominal trauma; however, it can occur in isolation. Acute traumatic rupture of the diaphragm may go unnoticed and there is often a delay between the injury and the diagnosis. Patients present with non-specific symptoms and may complain of chest pain, abdominal pain, dyspnoea, tachypnoea and cough, heartburn and symptoms of gastro-oesophageal reflux. Respiratory distress and faeco-pneumothorax have been reported. We present an interesting case of traumatic diaphragmatic hernia presenting 5 years after a road traffic accident as acute abdomen and massive haematemesis due to strangulated gangrenous gastric hernia.
International Journal of Business and Management, 2010
... 42 An Investigative Relationship between Efforts-Rewards Model and Job Stress in Private Educ... more ... 42 An Investigative Relationship between Efforts-Rewards Model and Job Stress in Private Educational Institutions: A Validation Study Saif ur Rehman Federal Government College of Commerce Sector H-8/4 Islamabad, Pakistan E-mail: saifurahman_fg@yahoo.com ...
Making correct decisions is an integral part of surgical competency and excellence. The learning ... more Making correct decisions is an integral part of surgical competency and excellence. The learning of this expert skill takes years to accumulate during training. To date there has not been an attempt to accelerate this learning process by developing a tool. In our present study we develop a self-appraisal computer software learning and assessment decision-making tool for laparoscopic surgery. It aims to accumulate several years of varied surgical experience, so the trainee can start to learn the complexities of surgical decision making in various types of cases. In this study we aim to validate the tool. Three decision-making modules were developed in a computer program for laparoscopic cholecystectomy: knowledge of operation, operative surgical technique and operative task completion. The latter two modules were based on answering questions based on watching recorded live operations from a library of 100 recorded laparoscopic cholecystectomies of various grades. The questions were devised by two experienced surgeons with more than 14 years postgraduate surgical experience. To validate the tool two groups with varying surgical experience were assessed: intermediate and expert surgeons. These groups were determined by the number of laparoscopic cholecystectomies performed as well as of number of years of operative surgical experience. A total of 20 subjects were assessed, 12 intermediate and 8 experts surgeons. Mean time to perform the programme was 21 min (range 18-45 min). Using the Mann-Whitney test, p < 0.05, construct validity was demonstrated in the surgical technique and completion of task modules as well as the total combined scores. Our computer-based decision-making learning tool for laparoscopic cholecystectomy seems to have face, content, concurrent and construct validities. Surgical decision making is a multifaceted process; by assessing how and why decisions are made effectively, focussed surgical training may be achieved. We aim in the future to determine if the self-appraisal decision-making tool improves or accelerates surgical training.
The Journal of Thoracic and Cardiovascular Surgery, 1997
The first objective was to determine the effect of inherited differences in the classic pathway c... more The first objective was to determine the effect of inherited differences in the classic pathway complement protein C4 on complement activation by heparin-protamine complexes in cardiac surgery. Specifically, we hypothesized that patients with heterozygous C4A null phenotype (A0BB), who have decreased amounts of C4A, may have increased complement activation because of reduced clearance of heparin-protamine complexes. The second objective was to determine whether heparin-protamine-induced complement activation correlated with postoperative pulmonary shunt fractions. C4 typing was performed by agarose gel immunofixation and crossed immunoelectrophoresis. Complement activation was measured by radioimmunoassay of C3a and C4a before cardiopulmonary bypass, after bypass, and after protamine infusion. Shunt fractions were calculated from blood gases. Of the 79 patients, 18 expressed heterozygous C4A null allele (A0BB), 16 had heterozygous C4B null allele (AAB0), three had homozygous C4B null alleles (AA00), and the rest expressed both C4A and C4B alleles (AABB). Patients with heterozygous C4A null allele had significantly increased plasma levels of C4a after protamine neutralization of heparin (C4a of 2862 +/- 375 ng/ml; mean +/- standard error of the mean) when compared with patients with normal expression of C4 alleles (AABB) (C4a of 1580 +/- 141 ng/ml) or heterozygous C4B null allele (C4a 1526 +/- 208 ng/ml). Pulmonary shunt fractions obtained after the operation correlated with the classic pathway complement activation by heparin-protamine complexes, but not with alternative pathway complement activation during cardiopulmonary bypass. Patients with heterozygous C4A null phenotype have increased complement activation by heparin-protamine complexes during cardiac operations, possibly because of their defective clearance. The classic pathway complement activation by heparin-protamine interaction correlates with postoperative pulmonary shunt fractions.
To evaluate the effects of dexmedetomidine on hypoxic pulmonary vasoconstriction (HPV) and oxygen... more To evaluate the effects of dexmedetomidine on hypoxic pulmonary vasoconstriction (HPV) and oxygenation during one-lung ventilation (OLV) in adults undergoing thoracic surgery. Prospective, randomized, double-blinded trial. Tertiary care, University-based hospital. Nineteen adult patients undergoing thoracic surgery requiring OLV. During inhalational anesthesia with desflurane, patients were randomized to receive either dexmedetomidine (bolus dose of 0.3 μg/kg followed by an infusion of 0.3 μg/kg/hr) or saline placebo. Three arterial blood gas samples (ABG) were obtained to evaluate the effects of dexmedetomidine on oxygenation. Secondary outcomes included differences in hemodynamic parameters (heart rate and mean arterial pressure), end-tidal desflurane concentration required to maintain the bispectral index (BIS) at 40-60, supplemental fentanyl to maintain hemodynamic stability, and phenylephrine to keep the mean arterial pressure (MAP) within 10% of baseline values. Oxygenation during OLV did not change following the administration of dexmedetomidine (PaO2/FiO2 ratio of 188 ± 115 in dexmedetomidine patients versus 135 ± 70 mmHg in placebo patients). There were no differences in hemodynamic variables or depth of anaesthesia between the two groups. With the administration of dexmedetomidine, there was a decrease in the expired concentration of desflurane required to maintain the BIS at 40-60 when compared with the control group (4.5 ± 0.8% versus 5.1 ± 0.8%). In patients receiving dexmedetomidine, fentanyl requirements were decreased when compared to placebo (2.7 μg/kg/patient versus 3.1 μg/kg/patient). However, more patients receiving dexmedetomidine required phenylephrine to maintain hemodynamic stability (6 of 9 patients versus 3 of 10 patients) and the total dose of phenylephrine was greater in patients receiving dexmedetomidine when compared with placebo 10.3 μg/kg/patient versus 1.1 μg/kg/patient). Dexmedetomidine does not adversely affect oxygenation during OLV in adults undergoing thoracic surgical procedures. The improvement in oxygenation in the dexmedetomidine patients may be related to a decrease in the requirements for inhalational anaesthetic agents thereby limiting its effects on HPV.
International journal of clinical and experimental medicine, 2013
In the pediatric hematology-oncology population, lumbar punctures (LP's) are commonly perform... more In the pediatric hematology-oncology population, lumbar punctures (LP's) are commonly performed to administer intrathecal chemotherapy and obtain CSF samples. Difficult LP's can arise due to obesity, fibrous tissue formation due to repeated LP procedures, or spinal abnormalities. For difficult LP's that require imaging-guidance, fluoroscopy is generally?? Fluoroscopy, however, subjects the patient and healthcare providers to radiation while also potentially increasing procedure cost and time. We retrospectively studied the utility of ultrasound-guidance to facilitate LP in 4 pediatric hematology-oncology patients. All 4 patients had a history of difficult LP and 3 of 4 had previously required use of fluoroscopy. With the use of ultrasound, the LP was successfully performed in all 4 patients with one attempt (number of attempts not recorded in one patient). Procedure time was less than 20 minutes in all 4 patients. Our preliminary data suggests that ultrasound may be an e...
Summary The continuum damage mechanics is used to describe the constitutive behavior of UD lamina... more Summary The continuum damage mechanics is used to describe the constitutive behavior of UD laminate with damage. The progressive fiber fracture, as it is affected by interface strength, debonding growth and matrix cracking, is considered as a main damage mechanism causing the stiffness reduction. The internal state variable that accounts for fiber fracture is formulated within the used theory. The
The effects of extreme environmental conditions on damage evolution and lifetime of long fiber po... more The effects of extreme environmental conditions on damage evolution and lifetime of long fiber polymer based composites are studied experimentally and theoretically. The exposure to salt water is the extreme environmental conditions that are considered in this study. The ...
Permian and Paleocene-Eocene limestone outcrops are exposed in Western Salt Range that contains c... more Permian and Paleocene-Eocene limestone outcrops are exposed in Western Salt Range that contains colossal quantity of mineable aggregates. Engineering properties of Wargal and Lockhart formations, Sakesar Limestone and Kalabagh Conglomerate indicated that these crushed rock aggregates could safely be used in civil work projects. Values calculated for Permian and Paleocene-Eocene limestone resources for specific gravity, water absorption, soundness, Los Angeles abrasion test, Proctor test, optimum moisture content, California bearing ratio and bitumen adhesion were much below the prescribed standards. These aggregates exhibited excellent petrographic properties and were innocuous in plain cement concrete. Moreover, they found to be hydrophobic in nature and therefore, their bond with bitumen would be durable. Development of quarries, following the environmental codes, around Dhak Pass area would provide low cost good quality crushed rock aggregate resources for Mianwali, Jhang, Bhakka...
The Kawagarh Formation is dominantly composed of limestone with subordinate dolomite and marl. It... more The Kawagarh Formation is dominantly composed of limestone with subordinate dolomite and marl. It was deposited in warm tropical homoclinal ramp settings at 23˚S latitude when the Indian Peninsula collided with the Kohistan Island Arc at ca. 65 Ma. The present study involves detailed sampling of eight stratigraphic sections, petrographic analysis (n=880), XRD (n=15), major (Ca and Mg) and minor (Sr, Na, Mn and Fe) trace element geochemistry (n=110), and stable isotopic (δ18O and δ13C) signatures (n=32). The petrographic studies demonstrate that Kawagarh Formation has been subjected to complex diagenetic history including compaction, minor dripstone, meniscus cementation and dolomitization. Close packing of grains, point contacts, dissolution seams and stylolites indicate effects of both mechanical and chemical compaction. Mostly dissolution seams are parallel to bedding and may have dolomite or clays. Stable isotope analyses indicate depleted δ18O signatures (-3.70 to -7.81‰ PDB) of...
Present studies document the temporal variations in petrographic, geochemical and isotopic signat... more Present studies document the temporal variations in petrographic, geochemical and isotopic signatures observed a thick siliciclastic and carbonate succession in Kawagarh Formation (Late Turonian to Lower Maastrichtian), Hazara Basin, NW Lesser Himalayas, Pakistan. In Lower Maastrichtian, the Hazara Basin exposed when Indian Plate established its contact in the north with Kohistan Island Arc. The Kawagarh Formaion is composed of limestone with subordinate dolomite/dolostone and marls. The limestone is fine grained and breaks with conchoidal fractures. The dolomite in all the studied sections of Kawagarh Formation is fine crystalline to coarse crystalline. The crystal texture of the dolomite in replacement mosaics varies from hypidiotopic to idiotopic. Minor amounts of dolomite crystals are xenotopic. At places, turbid cores, rhombic to irregular in shape were observed. Major and trace element studies (Ca, Mg, Sr, Na, Mn and Fe), stable isotopes (δ18O and δ13C) and X-ray diffraction a...
Diaphragmatic injuries are quite uncommon and often result from either blunt or penetrating traum... more Diaphragmatic injuries are quite uncommon and often result from either blunt or penetrating trauma. Diaphragmatic ruptures are usually associated with abdominal trauma; however, it can occur in isolation. Acute traumatic rupture of the diaphragm may go unnoticed and there is often a delay between the injury and the diagnosis. Patients present with non-specific symptoms and may complain of chest pain, abdominal pain, dyspnoea, tachypnoea and cough, heartburn and symptoms of gastro-oesophageal reflux. Respiratory distress and faeco-pneumothorax have been reported. We present an interesting case of traumatic diaphragmatic hernia presenting 5 years after a road traffic accident as acute abdomen and massive haematemesis due to strangulated gangrenous gastric hernia.
International Journal of Business and Management, 2010
... 42 An Investigative Relationship between Efforts-Rewards Model and Job Stress in Private Educ... more ... 42 An Investigative Relationship between Efforts-Rewards Model and Job Stress in Private Educational Institutions: A Validation Study Saif ur Rehman Federal Government College of Commerce Sector H-8/4 Islamabad, Pakistan E-mail: saifurahman_fg@yahoo.com ...
Making correct decisions is an integral part of surgical competency and excellence. The learning ... more Making correct decisions is an integral part of surgical competency and excellence. The learning of this expert skill takes years to accumulate during training. To date there has not been an attempt to accelerate this learning process by developing a tool. In our present study we develop a self-appraisal computer software learning and assessment decision-making tool for laparoscopic surgery. It aims to accumulate several years of varied surgical experience, so the trainee can start to learn the complexities of surgical decision making in various types of cases. In this study we aim to validate the tool. Three decision-making modules were developed in a computer program for laparoscopic cholecystectomy: knowledge of operation, operative surgical technique and operative task completion. The latter two modules were based on answering questions based on watching recorded live operations from a library of 100 recorded laparoscopic cholecystectomies of various grades. The questions were devised by two experienced surgeons with more than 14 years postgraduate surgical experience. To validate the tool two groups with varying surgical experience were assessed: intermediate and expert surgeons. These groups were determined by the number of laparoscopic cholecystectomies performed as well as of number of years of operative surgical experience. A total of 20 subjects were assessed, 12 intermediate and 8 experts surgeons. Mean time to perform the programme was 21 min (range 18-45 min). Using the Mann-Whitney test, p < 0.05, construct validity was demonstrated in the surgical technique and completion of task modules as well as the total combined scores. Our computer-based decision-making learning tool for laparoscopic cholecystectomy seems to have face, content, concurrent and construct validities. Surgical decision making is a multifaceted process; by assessing how and why decisions are made effectively, focussed surgical training may be achieved. We aim in the future to determine if the self-appraisal decision-making tool improves or accelerates surgical training.
The Journal of Thoracic and Cardiovascular Surgery, 1997
The first objective was to determine the effect of inherited differences in the classic pathway c... more The first objective was to determine the effect of inherited differences in the classic pathway complement protein C4 on complement activation by heparin-protamine complexes in cardiac surgery. Specifically, we hypothesized that patients with heterozygous C4A null phenotype (A0BB), who have decreased amounts of C4A, may have increased complement activation because of reduced clearance of heparin-protamine complexes. The second objective was to determine whether heparin-protamine-induced complement activation correlated with postoperative pulmonary shunt fractions. C4 typing was performed by agarose gel immunofixation and crossed immunoelectrophoresis. Complement activation was measured by radioimmunoassay of C3a and C4a before cardiopulmonary bypass, after bypass, and after protamine infusion. Shunt fractions were calculated from blood gases. Of the 79 patients, 18 expressed heterozygous C4A null allele (A0BB), 16 had heterozygous C4B null allele (AAB0), three had homozygous C4B null alleles (AA00), and the rest expressed both C4A and C4B alleles (AABB). Patients with heterozygous C4A null allele had significantly increased plasma levels of C4a after protamine neutralization of heparin (C4a of 2862 +/- 375 ng/ml; mean +/- standard error of the mean) when compared with patients with normal expression of C4 alleles (AABB) (C4a of 1580 +/- 141 ng/ml) or heterozygous C4B null allele (C4a 1526 +/- 208 ng/ml). Pulmonary shunt fractions obtained after the operation correlated with the classic pathway complement activation by heparin-protamine complexes, but not with alternative pathway complement activation during cardiopulmonary bypass. Patients with heterozygous C4A null phenotype have increased complement activation by heparin-protamine complexes during cardiac operations, possibly because of their defective clearance. The classic pathway complement activation by heparin-protamine interaction correlates with postoperative pulmonary shunt fractions.
To evaluate the effects of dexmedetomidine on hypoxic pulmonary vasoconstriction (HPV) and oxygen... more To evaluate the effects of dexmedetomidine on hypoxic pulmonary vasoconstriction (HPV) and oxygenation during one-lung ventilation (OLV) in adults undergoing thoracic surgery. Prospective, randomized, double-blinded trial. Tertiary care, University-based hospital. Nineteen adult patients undergoing thoracic surgery requiring OLV. During inhalational anesthesia with desflurane, patients were randomized to receive either dexmedetomidine (bolus dose of 0.3 μg/kg followed by an infusion of 0.3 μg/kg/hr) or saline placebo. Three arterial blood gas samples (ABG) were obtained to evaluate the effects of dexmedetomidine on oxygenation. Secondary outcomes included differences in hemodynamic parameters (heart rate and mean arterial pressure), end-tidal desflurane concentration required to maintain the bispectral index (BIS) at 40-60, supplemental fentanyl to maintain hemodynamic stability, and phenylephrine to keep the mean arterial pressure (MAP) within 10% of baseline values. Oxygenation during OLV did not change following the administration of dexmedetomidine (PaO2/FiO2 ratio of 188 ± 115 in dexmedetomidine patients versus 135 ± 70 mmHg in placebo patients). There were no differences in hemodynamic variables or depth of anaesthesia between the two groups. With the administration of dexmedetomidine, there was a decrease in the expired concentration of desflurane required to maintain the BIS at 40-60 when compared with the control group (4.5 ± 0.8% versus 5.1 ± 0.8%). In patients receiving dexmedetomidine, fentanyl requirements were decreased when compared to placebo (2.7 μg/kg/patient versus 3.1 μg/kg/patient). However, more patients receiving dexmedetomidine required phenylephrine to maintain hemodynamic stability (6 of 9 patients versus 3 of 10 patients) and the total dose of phenylephrine was greater in patients receiving dexmedetomidine when compared with placebo 10.3 μg/kg/patient versus 1.1 μg/kg/patient). Dexmedetomidine does not adversely affect oxygenation during OLV in adults undergoing thoracic surgical procedures. The improvement in oxygenation in the dexmedetomidine patients may be related to a decrease in the requirements for inhalational anaesthetic agents thereby limiting its effects on HPV.
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