It is shown that some well-known and some new cyclic codes with orthogonal parity-check equations... more It is shown that some well-known and some new cyclic codes with orthogonal parity-check equations can be constructed in the finite-field transform domain. It is also s hown that, for some binary linear cyclic codes, the performance of the iterative decoder can be improved by substituting some of the dual code codewords in the parity-check matrix with other dual code
The Hamming weight enumerator function of the formally self-dual even, binary extended quadratic ... more The Hamming weight enumerator function of the formally self-dual even, binary extended quadratic residue code of prime p = 8m + 1 is given by Gleason's theorem for singly-even code. Using this theorem, the Hamming weight distribution of the extended quadratic residue is completely determined once the number of codewords of Hamming weight j Aj, for 0 j 2m, are known. The smallest prime for which the Hamming weight distribution of the corresponding extended quadratic residue code is unknown is 137. It is shown in this paper that, for p = 137 A2m = A34 may be obtained without the need of exhaustive codeword enumeration. After the remainder of Aj required by Gleason's theorem are computed and independently verified using their congru- ences, the Hamming weight distributions of the binary augmented and extended quadratic residue codes of prime 137 are derived.
Pituitary gland is an uncommon site of a primary cancer. Of more than 600 cases of pituitary tumo... more Pituitary gland is an uncommon site of a primary cancer. Of more than 600 cases of pituitary tumors seen at the KFSH&RC between 1975 to 1998 only 3 patients had primary pituitary cancer. We have previously reported a case of pituitary fibrosarcoma arising as a rare complication of external radiotherapy (ERT) for GH-secreting pituitary adenoma (PA) [1]. We report now 2 cases of ACTH-producing primary pituitary carcinoma (ACTH-PPC); their follow-up data provide information on the natural history of this cancer. Patient #1; a 46 year old lady with Cushing's disease (CD) presented with an enlarged right cervical lymph node (LN) 2 years after having undergone a partial hypophysectomy through transsphenoidal surgery (PHYPX/TSS) and ERT for an invasive pituitary tumor. Patient #2; a 26 year old man presented with CD and underwent bilateral adrenalectomy (ADx) and pituitary ERT. Thirty-nine months later he developed Nelson's syndrome and a PHYPX/TSS was performed. Incidentally disco...
(+)-Gossypol was isolated from the bark of Thespesia populnea and tested for its ability to inhib... more (+)-Gossypol was isolated from the bark of Thespesia populnea and tested for its ability to inhibit the fertility of male hamsters. Male hamsters of proven fertility were treated orally for 54 days with 40 mg/kg of (+)-gossypol, 40 mg/kg of racemic gossypol, or 5% gum acacia (vehicle control) and were mated with estrous female hamsters during the fourth and seventh weeks of treatment. Both the control and the (+)-gossypol-treated animals exhibited normal fertility throughout the experiment. The racemic gossypol-treated animals were infertile when evaluated during both the fourth and seventh weeks of treatment. Morphologic examination of the testicular tissue could not explain the loss of fertility. These data demonstrate the inability of (+)gossypol to decrease male fertility and suggest that the activity of racemic gossypol may be due primarily to the presence of the (-) optical isomer.
Homozygous sickle cell disease in the eastern province of Saudi Arabia is clinically mild. Circul... more Homozygous sickle cell disease in the eastern province of Saudi Arabia is clinically mild. Circulating fetal hemoglobin levels of 16.0 +/- 7.4% were found in these anemic patients, but only 1.09 +/- 0.97% in their sickle trait parents. To determine whether these sickle cell anemia patients inherit an increased capacity to synthesize fetal hemoglobin, a radioimmunoassay of fetal and adult hemoglobin was performed on erythroid progenitor (BFU-E)-derived erythroblasts from Saudi Arabian sickle cell patients and their parents. Mean fetal hemoglobin content per BFU-E-derived erythroblast from Saudi Arabian sickle cell patients was 6.2 +/- 2.4 pg/cell or 30.4 +/- 8.6% fetal hemoglobin (normal 1.1 +/- 0.7 pg/cell and 5.1 +/- 1.8%). Linear regression analysis of % HbF in peripheral blood versus % HbF per BFU-E-derived cell showed a positive correlation with an r of 0.65. The variance of the intrinsic capacity to produce HbF may account for almost 40% (r2) of the variance of circulating feta...
The laparoscopic approach for adrenalectomy is now widely accepted and preferred over the convent... more The laparoscopic approach for adrenalectomy is now widely accepted and preferred over the conventional open approach. We describe our experience of adreanalectomy and compare the results of open and laparoscopic approach. From March 1999 to March 2002, we performed 23 adrenalectomies. An anterior transabdominal approach was used for the open procedure, and a lateral transperitoneal approach for the laparoscopic procedure. Data from both groups were analyzed and compared. There was no difference in tumor size or pathology between two groups. The tumor size was smaller, operative time was longer and estimated blood loss was less in the laparoscopic procedure group, however these differences were statistically insignificant. The mean length of hospital stay was shorter (5.1 vs. 9.2 days, P<0.01), the mean use of postoperative narcotic analgesia was less (4.2 vs. 8.1 injections, P<0.05), and the mean time for resumption of oral intake was faster (1.17 vs. 2 days, P<0.01) in the...
A 17-year old single woman had mandibulectomy twice at two different outside hospitals for a left... more A 17-year old single woman had mandibulectomy twice at two different outside hospitals for a left mandibular mass 16 months prior to presentation. She was left with a foul smelling, disfiguring, draining sinus. Evaluation at the outside hospital showed diffuse skeletal &amp;amp;amp;amp;amp;amp;amp;amp;quot;lytic ...
2010 IEEE International Conference on Communication Systems, 2010
Abstract The paper presents closed-form expressions for the detection, and false alarm probabilit... more Abstract The paper presents closed-form expressions for the detection, and false alarm probabilities for spectrum sensing detection in Additive White Gaussian Noise (AWGN) based on the Multitaper Spectrum Estimation Method (MTM) using Neyman-Pearson ...
A new method of finding binary cyclic codes from the finite-field transform domain is presented. ... more A new method of finding binary cyclic codes from the finite-field transform domain is presented. These cyclic codes have sparse parity-check matrix and thus are suitable for iterative decoding. Some interesting properties of the proposed construction method include the knowledge of the minimum distance and the ability to trade the increase in code dimension with a reduction in the parity-check matrix sparsity. By means of simulations, we show that the error correcting performance of the codes under iterative decoding is very close to the sphere-packing-bound constrained for binary transmission.
2006 IEEE Information Theory Workshop - ITW '06 Chengdu, 2006
ABSTRACT An efficient algorithm to count all codewords of given weight and a method to deduce the... more ABSTRACT An efficient algorithm to count all codewords of given weight and a method to deduce the modular congruence of the weight distributions of the binary quadratic double-circulant codes are presented. Using this algorithm, we give the weight distribution of the quadratic double-circulant code of length 168 and that of the extended quadratic-residue code of the same length. The weight distributions of these two inequivalent codes of length 168, which were previously unknown, are independently verified and proved to be accurate using the modular congruence method
2010 IEEE International Conference on Wireless Communications, Networking and Information Security, 2010
Abstract-We present 75 codes over finite field IF16 which improve on the best known codes of the ... more Abstract-We present 75 codes over finite field IF16 which improve on the best known codes of the same length and rate. These codes are generalised algebraic geometry codes constructed using function fields with many places of small degree with a technique originally ...
The journal of physical chemistry. B, Jan 22, 2013
Water in the presence of electrolytes plays an important role in biological and industrial proces... more Water in the presence of electrolytes plays an important role in biological and industrial processes. The properties of water, such as the intermolecular coupling, Fermi resonance (FR), hydrogen-bonding, and Raman cross section were investigated by measuring the Raman spectra in the OD and OH stretch regions in presence of alkali halides (NaX; X = F, Cl, Br, I). It is observed that the changes in spectral characteristics by the addition of NaX in D2O are similar to those obtained by the addition of H2O in D2O. The spectral width decreases significantly by the addition of NaX in D2O (H2O) than that in the isotopically diluted water. Quantitative estimation, on the basis of integrated Raman intensity, revealed that the relative Raman cross section, σ(H)/σ(b) (σ(H) and σ(b) are the average Raman cross section of water in the first hydration shell of X(-) and in bulk, respectively), in D2O and H2O is higher than those in the respective isotopically diluted water. These results suggest t...
The hydration energy of an ion largely resides within the first few layers of water molecules in ... more The hydration energy of an ion largely resides within the first few layers of water molecules in its hydration shell. Hence, it is important to understand the transformation of water properties, such as hydrogen-bonding, intermolecular vibrational coupling, and librational freedom in the hydration shell of ions. We investigated these properties in the hydration shell of mono- (Cl(-) and I(-)) and bivalent (SO4(2-) and CO3(2-)) anions by using Raman multivariate curve resolution (Raman-MCR) spectroscopy in the OH stretch, HOH bend, and [bend+librational] combination bands of water. Raman-MCR of aqueous Na-salt (NaCl, NaI, Na2SO4, and Na2CO3) solutions provides ion-correlated spectra (IC-spectrum) which predominantly bear the vibrational characteristics of water in the hydration shell of respective anions. Comparison of these IC-spectra with the Raman spectrum of bulk water in different spectral regions reveals that the water is vibrationally decoupled with its neighbors in the hydrat...
CCL21 acting through CCR7, is termed a homeostatic chemokine. Based on its role in concerting imm... more CCL21 acting through CCR7, is termed a homeostatic chemokine. Based on its role in concerting immunological responses and its proposed involvement in tissue remodeling, we hypothesized that this chemokine could play a role in myocardial remodeling during left ventricular (LV) pressure overload. Our main findings were: (i) Serum levels of CCL21 were markedly raised in patients with symptomatic aortic stenosis (AS, n = 136) as compared with healthy controls (n = 20). (ii) A CCL21 level in the highest tertile was independently associated with all-cause mortality in these patients. (iii) Immunostaining suggested the presence of CCR7 on macrophages, endothelial cells and fibroblasts within calcified human aortic valves. (iv). Mice exposed to LV pressure overload showed enhanced myocardial expression of CCL21 and CCR7 mRNA, and increased CCL21 protein levels. (v) CCR7-/- mice subjected to three weeks of LV pressure overload had similar heart weights compared to wild type mice, but increas...
Skin development is governed by complex programs of gene activation and silencing, including micr... more Skin development is governed by complex programs of gene activation and silencing, including microRNA-dependent modulation of gene expression. Here, we show that miR-214 regulates skin morphogenesis and hair follicle (HF) cycling by targeting β-catenin, a key component of the Wnt signaling pathway. miR-214 exhibits differential expression patterns in the skin epithelium, and its inducible overexpression in keratinocytes inhibited proliferation, which resulted in formation of fewer HFs with decreased hair bulb size and thinner hair production. The inhibitory effects of miR-214 on HF development and cycling were associated with altered activities of multiple signaling pathways, including decreased expression of key Wnt signaling mediators β-catenin and Lef-1, and were rescued by treatment with pharmacological Wnt activators. Finally, we identify β-catenin as one of the conserved miR-214 targets in keratinocytes. These data provide an important foundation for further analyses of miR-21...
2003 International Conference on Geometric Modeling and Graphics, 2003. Proceedings, 2003
Page 1. Saudi Arabian License Plate Recognition System Muhammad Sarfraz, Mohammed Jameel Ahmed, a... more Page 1. Saudi Arabian License Plate Recognition System Muhammad Sarfraz, Mohammed Jameel Ahmed, and Syed A. Ghazi Department of Information and Computer Science, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia. ...
It is shown that some well-known and some new cyclic codes with orthogonal parity-check equations... more It is shown that some well-known and some new cyclic codes with orthogonal parity-check equations can be constructed in the finite-field transform domain. It is also s hown that, for some binary linear cyclic codes, the performance of the iterative decoder can be improved by substituting some of the dual code codewords in the parity-check matrix with other dual code
The Hamming weight enumerator function of the formally self-dual even, binary extended quadratic ... more The Hamming weight enumerator function of the formally self-dual even, binary extended quadratic residue code of prime p = 8m + 1 is given by Gleason's theorem for singly-even code. Using this theorem, the Hamming weight distribution of the extended quadratic residue is completely determined once the number of codewords of Hamming weight j Aj, for 0 j 2m, are known. The smallest prime for which the Hamming weight distribution of the corresponding extended quadratic residue code is unknown is 137. It is shown in this paper that, for p = 137 A2m = A34 may be obtained without the need of exhaustive codeword enumeration. After the remainder of Aj required by Gleason's theorem are computed and independently verified using their congru- ences, the Hamming weight distributions of the binary augmented and extended quadratic residue codes of prime 137 are derived.
Pituitary gland is an uncommon site of a primary cancer. Of more than 600 cases of pituitary tumo... more Pituitary gland is an uncommon site of a primary cancer. Of more than 600 cases of pituitary tumors seen at the KFSH&RC between 1975 to 1998 only 3 patients had primary pituitary cancer. We have previously reported a case of pituitary fibrosarcoma arising as a rare complication of external radiotherapy (ERT) for GH-secreting pituitary adenoma (PA) [1]. We report now 2 cases of ACTH-producing primary pituitary carcinoma (ACTH-PPC); their follow-up data provide information on the natural history of this cancer. Patient #1; a 46 year old lady with Cushing's disease (CD) presented with an enlarged right cervical lymph node (LN) 2 years after having undergone a partial hypophysectomy through transsphenoidal surgery (PHYPX/TSS) and ERT for an invasive pituitary tumor. Patient #2; a 26 year old man presented with CD and underwent bilateral adrenalectomy (ADx) and pituitary ERT. Thirty-nine months later he developed Nelson's syndrome and a PHYPX/TSS was performed. Incidentally disco...
(+)-Gossypol was isolated from the bark of Thespesia populnea and tested for its ability to inhib... more (+)-Gossypol was isolated from the bark of Thespesia populnea and tested for its ability to inhibit the fertility of male hamsters. Male hamsters of proven fertility were treated orally for 54 days with 40 mg/kg of (+)-gossypol, 40 mg/kg of racemic gossypol, or 5% gum acacia (vehicle control) and were mated with estrous female hamsters during the fourth and seventh weeks of treatment. Both the control and the (+)-gossypol-treated animals exhibited normal fertility throughout the experiment. The racemic gossypol-treated animals were infertile when evaluated during both the fourth and seventh weeks of treatment. Morphologic examination of the testicular tissue could not explain the loss of fertility. These data demonstrate the inability of (+)gossypol to decrease male fertility and suggest that the activity of racemic gossypol may be due primarily to the presence of the (-) optical isomer.
Homozygous sickle cell disease in the eastern province of Saudi Arabia is clinically mild. Circul... more Homozygous sickle cell disease in the eastern province of Saudi Arabia is clinically mild. Circulating fetal hemoglobin levels of 16.0 +/- 7.4% were found in these anemic patients, but only 1.09 +/- 0.97% in their sickle trait parents. To determine whether these sickle cell anemia patients inherit an increased capacity to synthesize fetal hemoglobin, a radioimmunoassay of fetal and adult hemoglobin was performed on erythroid progenitor (BFU-E)-derived erythroblasts from Saudi Arabian sickle cell patients and their parents. Mean fetal hemoglobin content per BFU-E-derived erythroblast from Saudi Arabian sickle cell patients was 6.2 +/- 2.4 pg/cell or 30.4 +/- 8.6% fetal hemoglobin (normal 1.1 +/- 0.7 pg/cell and 5.1 +/- 1.8%). Linear regression analysis of % HbF in peripheral blood versus % HbF per BFU-E-derived cell showed a positive correlation with an r of 0.65. The variance of the intrinsic capacity to produce HbF may account for almost 40% (r2) of the variance of circulating feta...
The laparoscopic approach for adrenalectomy is now widely accepted and preferred over the convent... more The laparoscopic approach for adrenalectomy is now widely accepted and preferred over the conventional open approach. We describe our experience of adreanalectomy and compare the results of open and laparoscopic approach. From March 1999 to March 2002, we performed 23 adrenalectomies. An anterior transabdominal approach was used for the open procedure, and a lateral transperitoneal approach for the laparoscopic procedure. Data from both groups were analyzed and compared. There was no difference in tumor size or pathology between two groups. The tumor size was smaller, operative time was longer and estimated blood loss was less in the laparoscopic procedure group, however these differences were statistically insignificant. The mean length of hospital stay was shorter (5.1 vs. 9.2 days, P<0.01), the mean use of postoperative narcotic analgesia was less (4.2 vs. 8.1 injections, P<0.05), and the mean time for resumption of oral intake was faster (1.17 vs. 2 days, P<0.01) in the...
A 17-year old single woman had mandibulectomy twice at two different outside hospitals for a left... more A 17-year old single woman had mandibulectomy twice at two different outside hospitals for a left mandibular mass 16 months prior to presentation. She was left with a foul smelling, disfiguring, draining sinus. Evaluation at the outside hospital showed diffuse skeletal &amp;amp;amp;amp;amp;amp;amp;amp;quot;lytic ...
2010 IEEE International Conference on Communication Systems, 2010
Abstract The paper presents closed-form expressions for the detection, and false alarm probabilit... more Abstract The paper presents closed-form expressions for the detection, and false alarm probabilities for spectrum sensing detection in Additive White Gaussian Noise (AWGN) based on the Multitaper Spectrum Estimation Method (MTM) using Neyman-Pearson ...
A new method of finding binary cyclic codes from the finite-field transform domain is presented. ... more A new method of finding binary cyclic codes from the finite-field transform domain is presented. These cyclic codes have sparse parity-check matrix and thus are suitable for iterative decoding. Some interesting properties of the proposed construction method include the knowledge of the minimum distance and the ability to trade the increase in code dimension with a reduction in the parity-check matrix sparsity. By means of simulations, we show that the error correcting performance of the codes under iterative decoding is very close to the sphere-packing-bound constrained for binary transmission.
2006 IEEE Information Theory Workshop - ITW '06 Chengdu, 2006
ABSTRACT An efficient algorithm to count all codewords of given weight and a method to deduce the... more ABSTRACT An efficient algorithm to count all codewords of given weight and a method to deduce the modular congruence of the weight distributions of the binary quadratic double-circulant codes are presented. Using this algorithm, we give the weight distribution of the quadratic double-circulant code of length 168 and that of the extended quadratic-residue code of the same length. The weight distributions of these two inequivalent codes of length 168, which were previously unknown, are independently verified and proved to be accurate using the modular congruence method
2010 IEEE International Conference on Wireless Communications, Networking and Information Security, 2010
Abstract-We present 75 codes over finite field IF16 which improve on the best known codes of the ... more Abstract-We present 75 codes over finite field IF16 which improve on the best known codes of the same length and rate. These codes are generalised algebraic geometry codes constructed using function fields with many places of small degree with a technique originally ...
The journal of physical chemistry. B, Jan 22, 2013
Water in the presence of electrolytes plays an important role in biological and industrial proces... more Water in the presence of electrolytes plays an important role in biological and industrial processes. The properties of water, such as the intermolecular coupling, Fermi resonance (FR), hydrogen-bonding, and Raman cross section were investigated by measuring the Raman spectra in the OD and OH stretch regions in presence of alkali halides (NaX; X = F, Cl, Br, I). It is observed that the changes in spectral characteristics by the addition of NaX in D2O are similar to those obtained by the addition of H2O in D2O. The spectral width decreases significantly by the addition of NaX in D2O (H2O) than that in the isotopically diluted water. Quantitative estimation, on the basis of integrated Raman intensity, revealed that the relative Raman cross section, σ(H)/σ(b) (σ(H) and σ(b) are the average Raman cross section of water in the first hydration shell of X(-) and in bulk, respectively), in D2O and H2O is higher than those in the respective isotopically diluted water. These results suggest t...
The hydration energy of an ion largely resides within the first few layers of water molecules in ... more The hydration energy of an ion largely resides within the first few layers of water molecules in its hydration shell. Hence, it is important to understand the transformation of water properties, such as hydrogen-bonding, intermolecular vibrational coupling, and librational freedom in the hydration shell of ions. We investigated these properties in the hydration shell of mono- (Cl(-) and I(-)) and bivalent (SO4(2-) and CO3(2-)) anions by using Raman multivariate curve resolution (Raman-MCR) spectroscopy in the OH stretch, HOH bend, and [bend+librational] combination bands of water. Raman-MCR of aqueous Na-salt (NaCl, NaI, Na2SO4, and Na2CO3) solutions provides ion-correlated spectra (IC-spectrum) which predominantly bear the vibrational characteristics of water in the hydration shell of respective anions. Comparison of these IC-spectra with the Raman spectrum of bulk water in different spectral regions reveals that the water is vibrationally decoupled with its neighbors in the hydrat...
CCL21 acting through CCR7, is termed a homeostatic chemokine. Based on its role in concerting imm... more CCL21 acting through CCR7, is termed a homeostatic chemokine. Based on its role in concerting immunological responses and its proposed involvement in tissue remodeling, we hypothesized that this chemokine could play a role in myocardial remodeling during left ventricular (LV) pressure overload. Our main findings were: (i) Serum levels of CCL21 were markedly raised in patients with symptomatic aortic stenosis (AS, n = 136) as compared with healthy controls (n = 20). (ii) A CCL21 level in the highest tertile was independently associated with all-cause mortality in these patients. (iii) Immunostaining suggested the presence of CCR7 on macrophages, endothelial cells and fibroblasts within calcified human aortic valves. (iv). Mice exposed to LV pressure overload showed enhanced myocardial expression of CCL21 and CCR7 mRNA, and increased CCL21 protein levels. (v) CCR7-/- mice subjected to three weeks of LV pressure overload had similar heart weights compared to wild type mice, but increas...
Skin development is governed by complex programs of gene activation and silencing, including micr... more Skin development is governed by complex programs of gene activation and silencing, including microRNA-dependent modulation of gene expression. Here, we show that miR-214 regulates skin morphogenesis and hair follicle (HF) cycling by targeting β-catenin, a key component of the Wnt signaling pathway. miR-214 exhibits differential expression patterns in the skin epithelium, and its inducible overexpression in keratinocytes inhibited proliferation, which resulted in formation of fewer HFs with decreased hair bulb size and thinner hair production. The inhibitory effects of miR-214 on HF development and cycling were associated with altered activities of multiple signaling pathways, including decreased expression of key Wnt signaling mediators β-catenin and Lef-1, and were rescued by treatment with pharmacological Wnt activators. Finally, we identify β-catenin as one of the conserved miR-214 targets in keratinocytes. These data provide an important foundation for further analyses of miR-21...
2003 International Conference on Geometric Modeling and Graphics, 2003. Proceedings, 2003
Page 1. Saudi Arabian License Plate Recognition System Muhammad Sarfraz, Mohammed Jameel Ahmed, a... more Page 1. Saudi Arabian License Plate Recognition System Muhammad Sarfraz, Mohammed Jameel Ahmed, and Syed A. Ghazi Department of Information and Computer Science, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia. ...
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Papers by Mohammed Ahmed