This review paper highlights the research on thrives for nitrate reduction by transition metal chalcogenides (TMCs) to produce ammonia. The exposure of humans to nitrate in the environment via public drinking water supplies is on the increase due to the elevated usage of inorganic fertilizers and animal manure in agricultural lands in various regions of the world. Many regions of the world has already set a permissible limit for nitrate in drinking water so as to prevent methemoglobinemia in children, birth defects, thyroid dysfunction and disease, various cancers, and cyanosis that culminates into asphyxia. Also, serious health disorders may occur due to ingestion of excess nitrate, such as cardiovascular disorder, genetic mutation, and diabetes. Recently, TMCs have attracted the keen interest of the scientists/researchers due to their unique tunable properties such as heterojunction formation with noble metals, morphological engineering through various synthesis techniques, elemental doping, and tunable edge active site and surface defects that induce active sites transformation at the basal planes. Irrespective of these unique surface properties, TMCs have the shortcomings of increasing surface hydrogen binding energy and Gibbs free energy change, which enhances charge-carrier separation and hydrogen evolution reaction (HER). Future research outlook should focus on the surface engineering of TMCs in terms of minimizing the formation of heterojunction, which will limit proton/electron-transfer kinetics, shifting the chemical equilibrium of HER through catalyst engineering that will mitigate the adsorption of hydrogen species, regulating the crystal phase, blocking the HER active sites, and introducing strain effects that will suppress HER and boost nitrogen reduction reaction (NRR). These strategies will suppress HER and increase the efficiency of NRR.

Ebstein anomaly is a rare congenital malformation defined by failed delamination and apical displacement of the tricuspid valve, which produces an atrialized segment of the right ventricle and variable right ventricular dysfunction. Its clinical expression is wide, ranging from severe neonatal cyanosis and heart failure, which carry high perinatal mortality, to incidental detection in adulthood. Because anatomy and physiology vary widely among patients, imaging is central to diagnosis, risk stratification, and treatment planning. Transthoracic echocardiography remains the first-line study and establishes the diagnosis through apical leaflet displacement, leaflet tethering, and right atrial dilation; three-dimensional and transesophageal echocardiography refine the assessment of leaflet morphology and the atrialized right ventricle. Cardiac magnetic resonance imaging quantifies right ventricular and right atrial volumes, ejection fraction, regurgitant volume, and myocardial fibrosis, and increasingly informs the timing of surgery; computed tomography is a complement when magnetic resonance is contraindicated or extracardiac anatomy must be defined. Management is guided by current European and North American congenital heart disease guidelines and is matched to symptom burden and anatomy. Transplacental non-steroidal anti-inflammatory drugs may relieve the circular shunt in selected fetuses. Cone reconstruction has become the preferred surgical repair, with valve replacement reserved for valves deemed unsuitable. Catheter-based options, including device closure of interatrial communications, accessory-pathway ablation, and transcatheter tricuspid valve-in-valve implantation, address specific problems in higher-risk patients, although dedicated transcatheter replacement remains investigational in this population. Long-term care depends on serial imaging to detect residual regurgitation, progressive ventricular dysfunction, and arrhythmia. This review summarizes the anatomy, pathophysiology, multimodality imaging, and contemporary therapy of Ebstein anomaly, with emphasis on how imaging findings translate into clinical decisions.

Ebstein's anomaly is an uncommon congenital defect of the tricuspid valve, marked by the apical displacement of the septal and posterior leaflets, leading to the "atrialization" of the right ventricle and subsequent dysfunction on the right side. Clinical manifestations vary from asymptomatic adults to neonates exhibiting severe cyanosis and heart failure. Advancements in diagnostic imaging, therapeutic interventions, and surgical techniques have significantly enhanced the prognosis for individuals afflicted by this historically serious condition. This review provides an in-depth examination of Ebstein's anomaly, discussing its embryological origins, underlying pathophysiology, clinical manifestations, diagnostic assessment, medical treatment protocols, and surgical interventions. Particular emphasis is placed on contemporary surgical options, including cone reconstruction, the Starnes procedure, one-and-a-half ventricle repair, and valve replacement.

Persistent pulmonary hypertension of the newborn (PPHN) arises from failure of the normal circulatory transition that occurs postnatally and is characterised by increased pulmonary vascular resistance, leading to significant respiratory distress and hypoxaemia. Oral sildenafil administration is a potential alternative treatment for PPHN, especially when inhaled nitric oxide is unavailable. A 72-hour-old term male neonate was referred on account of respiratory distress, and cyanosis was noticed at 30 minutes of life with RR of 76 bpm and SPO2 of 57% in room air. The baby was pale, cyanosed, icteric, and febrile (39.5°C). An initial assessment of Severe NNJ 20 to EONNS with background cyanotic congenital heart disease was made. An echocardiogram with colour Doppler interrogation confirmed the diagnosis of Persistent pulmonary hypertension of the newborn. The baby was commenced on compounded oral sildenafil @ 2mg/kg/dose 6 hourly in addition to oxygen therapy. Baby improved and was subsequently discharged home on oral sildenafil, which was discontinued after a normal repeat ECHO Scan done at 2 months of life. Oral compounded sildenafil was found to be a useful alternative in managing PPHN.

Abernethy malformation is a rare congenital extrahepatic portosystemic shunt (CEPSh) characterized by the diversion of portal venous blood away from the liver into the systemic circulation, resulting in a wide spectrum of hepatic, pulmonary, and systemic complications. Hepatopulmonary syndrome is an important but uncommon association that results from intrapulmonary vascular dilatation secondary to portosystemic shunting. We describe the case of a two-year-old female who was evaluated for recurrent respiratory tract infections, cyanosis, and digital clubbing. Radiologic assessment demonstrated a Type Ib Abernethy malformation characterized by the formation of a common spleno-mesenteric trunk draining directly into the inferior vena cava, complete diversion of portal venous flow, and the absence of intrahepatic portal venous radicals. CT pulmonary angiography further revealed dilated distal pulmonary vasculature compatible with hepatopulmonary syndrome. Prompt radiologic recognition of this rare vascular anomaly is crucial, particularly when pulmonary manifestations are present, as timely diagnosis and referral for definitive management, including liver transplantation, can significantly improve clinical outcomes.

Acquired methemoglobinemia is an uncommon but potentially life-threatening disorder characterized by oxidation of hemoglobin iron into the ferric state, resulting in impaired oxygen delivery and functional anemia. Patients may present with cyanosis, persistent hypoxemia, and discordance between pulse oximetry and arterial oxygen saturation (SaO2). Although medications and industrial chemicals are well-recognized causes, herbal and traditional remedies remain underreported aetiologies. A 35-year-old man presented with a sudden-onset generalized tonic-clonic seizure followed by persistent hypoxemia and peripheral cyanosis after ingestion of a home-prepared herbal (Ayurvedic) decoction. The blood sample demonstrated characteristic chocolate-brown discoloration. Oxygen saturation remained approximately 85% despite supplemental oxygen therapy. Arterial blood gas (ABG) analysis demonstrated preserved arterial oxygen tension (PaO2 167 mmHg) with a calculated SaO2 of 97.3%, indicating a characteristic saturation gap. Co-oximetry demonstrated a methemoglobin level of 19%. The diagnosis of methemoglobinemia was supported by refractory hypoxemia, cyanosis, chocolate-brown blood discoloration, saturation gap, and co-oximetry-confirmed methemoglobinemia (19%). The patient improved rapidly following treatment with intravenous methylene blue, anticonvulsants, and supportive care. There was a rapid disappearance of cyanosis; oxygen saturation returned to normal with full neurological recovery. This example highlights the importance of checking for methemoglobinemia in patients with symptoms of unexplained cyanosis, refractory hypoxemia, and a mismatch between pulse oximetry and arterial oxygen levels, particularly following exposure to herbal or traditional preparations. Recognition of these findings facilitated prompt diagnosis and treatment in our patient.

Pulmonary arteriovenous malformations (PAVMs) are rare vascular anomalies characterized by direct communication between the pulmonary arteries and veins, resulting in a right-to-left shunt and impaired gas exchange. Most cases are associated with hereditary hemorrhagic telangiectasia (HHT), while sporadic, complex lesions are uncommon and can be diagnostically challenging when clinical features overlap with more prevalent pulmonary disease. This is the case of a chronic smoker who was referred for pulmonary evaluation for suspected chronic obstructive pulmonary disease (COPD). She was found to have hypoxemia with cyanosis and digital clubbing. CT angiography (CTA) of the chest demonstrated right middle and right lower lobe PAVMs. Two consecutive interventions were performed to treat the malformations. She had persistent post-procedure hypoxemia, and a third intervention identified an additional large inferolateral right middle lobe PAVM with a smaller contributing branch, making this a case of a complex PAVM, which is an uncommon occurrence in patients without HHT.